We express our sincere appreciation for the financial support received from the Connotation Construction Project of the 14th Five-Year Plan of the University of Tibetan Medicine (2022ZYYGH12), the 2022 Open Subjects of the Key Laboratory of Tibetan Medicine and Basic Education of the Ministry of Education at the University of Tibetan Medicine (ZYYJC-22-04), the Key Research and Development Program of Ningxia (2023BEG02012), and the Xinglin Scholar Research Promotion Project of Chengdu University of Traditional Chinese Medicine (XKTD2022013).

The compound solution, protein solution, and dye were introduced into a PBS solution. Subsequently, the samples underwent gradual heating using a digital heating shaking dry bath, and the thermal stability of the proteins was evaluated by measuring the change in fluorescence intensity within the complex system. The detailed steps are outlined below, and Figure 1 illustrates an overview of the protocol.
1. Solution preparation
<ol>
	<li>Prepare a 1 mM umbelliferone solution by adding 0.1 mg of umbelliferone to 616.75 &#181;L of DMSO solution (see Table of Materials).</li>
	<li>Prepare a 200 &#181;g/mL CD40 protein solution by adding 0.1 mg of CD40 to 500 &#181;L of ddH2O solution (see Table of Materials).</li>
	<li>Prepare a 500x orange dye solution by adding 1 &#181;L of 5000x orange dye to 9 &#181;L of phosphate-buffered saline (PBS) (see Table of Materials). 
	NOTE: Perform the above operations on ice, and since the pipette has a minimum range of 0.1 &#181;L, initially dilute the orange protein-dye by a factor of 10 to facilitate subsequent use.</li>
</ol>
2. Dye performance testing
<ol>
	<li>Add the 500x orange dye to a PBS solution and dilute it to achieve dye: PBS ratios of 1:500, 1:1000, 1:2000, and 1:4000. 
	NOTE: Ensure that the final concentration of DMSO does not exceed 2% (v/v).</li>
	<li>Turn on the fluorescent microplate reader and preheat it for 10 min.</li>
	<li>Open the computer and the data acquisition software in sequence (see Table of Materials).</li>
	<li>Click on Instrument, choose the corresponding fluorescence microplate model, and select OK in the data acquisition software. 
	NOTE: Wait for the fluorescence microplate to finish preheating and display the temperature on the panel before opening the data acquisition software to ensure a successful connection between the instrument and the software.</li>
	<li>Click on Acquisition Settings and select Fluorescence in the data acquisition software.</li>
	<li>Edit the program in the Wavelengths interface: Lm1 = 470 nm, 570 nm, and then select OK. 
	NOTE: The orange dye can be excited with UV light at 300 nm or visible light at 470 nm, and emission can be measured at 570 nm.</li>
	<li>Add different concentrations of orange dye (1:500, 1:1000, 1:2000, and 1:4000) and PBS to 96-well plates at 100 &#181;L/well. 
	NOTE: Dissolve the solution in DMSO before adding it to PBS, and vortex it at 2000 x g thoroughly during the preparation process to ensure complete dissolution due to the dye&#39;s tendency to precipitate.</li>
	<li>Place the 96-well plate into the detection stage of the instrument, click on the Read button in the data acquisition software, and measure the fluorescence of each dye concentration 13 times at room temperature, with an interval of 2 min each time.</li>
	<li>Click on the Export button after each determination, select Export to XML XLS TXT, choose All Plates, then select Plate in Output Format, and finally click on OK to save the data in a folder in &#34;XLS&#34; format for further analysis. 
	NOTE: These steps help determine the impact of continuous measurement on the autofluorescence of the orange dye at room temperature and identify the optimal staining concentration.</li>
	<li>Turn on the digital heating shaking dry bath, set the heating temperature to 35 &#176;C, and the heating time to 2 min.</li>
	<li>Prepare the optimal dilution ratio of dye in a 1.5 mL microcentrifuge tube and place it in the digital heating shaking dry bath for 2 min.</li>
	<li>Add PBS solution and the staining solution, heated at 35 &#176;C, to the 96-well plate at a volume of 100 &#181;L per well.</li>
	<li>Place the 96-well plate into the detection stage of the instrument, and click on the Read button in the data acquisition software.</li>
	<li>Set the heating temperature to 40 &#176;C and the heating time to 2 min.</li>
	<li>Pipette the dye solution in the 96-well plate back into the 1.5 mL microcentrifuge tube and heat it in the instrument for 2 min.</li>
	<li>Repeat the operations of steps 2.12-2.15 and step 2.9 to test the absorbance of the dye solution at 35 &#176;C, 40 &#176;C, 45 &#176;C, 50 &#176;C, 55 &#176;C, 60 &#176;C, 65 &#176;C, 70 &#176;C, 75 &#176;C, 80 &#176;C, 85 &#176;C, 90 &#176;C, and 95 &#176;C, respectively. 
	NOTE: These steps help determine the stability of the autofluorescence of the orange dye under continuous heating in a gradient from 35 &#176;C to 95 &#176;C. It is crucial to work swiftly to avoid rapid temperature drops or adding the wrong liquid, which could lead to experimental errors.</li>
</ol>
3. Detection of the temperature melting (Tm) of the protein
<ol>
	<li>Combine CD40 protein and orange dye with PBS solution to achieve final concentrations of 5 &#181;g/mL, 10 &#181;g/mL, 15 &#181;g/mL, 20 &#181;g/mL, and 1:500, respectively.</li>
	<li>Repeat the operations outlined in steps 2.2-2.6 and steps 2.10-2.16 to assess the absorbance of the CD40 protein solution at temperatures of 35 &#176;C, 40 &#176;C, 45 &#176;C, 50 &#176;C, 55 &#176;C, 60 &#176;C, 65 &#176;C, 70 &#176;C, 75 &#176;C, 80 &#176;C, 85 &#176;C, 90 &#176;C, and 95 &#176;C, respectively.</li>
	<li>Reiterate step 2.9 to save and analyze the data, and subsequently calculate the Tm value using data analysis software (see Table of Materials).</li>
	<li>Add CD40 protein, umbelliferone, and orange dye to the PBS solution to obtain final concentrations of 5 &#181;g/mL, 10 &#181;g/mL, 15 &#181;g/mL, 20 &#181;g/mL, 10 &#181;M, and 1:500, respectively. 
	NOTE: Vigorous vortexing during solution preparation is essential to ensure even distribution of the dye, CD40 protein, and umbelliferone in PBS.</li>
	<li>Repeat the operations of steps 3.2-3.3&#160;to measure the absorbance of the CD40-umbelliferone complexes solution at temperatures of 35 &#176;C, 40 &#176;C, 45 &#176;C, 50 &#176;C, 55 &#176;C, 60 &#176;C, 65 &#176;C, 70 &#176;C, 75 &#176;C, 80 &#176;C, 85 &#176;C, 90 &#176;C, and 95 &#176;C, respectively. 
	NOTE: These steps were conducted to determine the Tm values of CD40 protein and CD40-umbelliferone complexes, aiming to identify the optimal CD40 protein binding concentration to umbelliferone.</li>
</ol>

High-Sensitivity Detection of Compound-Protein Binding Using Fluorescence

<ol>
	<li>Cairang, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+on+the+standardization+of+clinical+application+of+Tibetan+medicine+&amp;#34;five+roots&amp;#34.">Study on the standardization of clinical application of Tibetan medicine &amp;#34;five roots&amp;#34.</a> Guid J Trad Chin Med Pharm. 28 (11), 133136 (2022).</li><li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Xigui+extract+on+immunosuppressive+mice+induced+by+cyclophosphamide.">Effects of Xigui extract on immunosuppressive mice induced by cyclophosphamide.</a> Chin J Hosp Pharm. 37 (03), 244-247 (2017).</li><li>Lu, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Vicatia+thibertica+de+boiss+on+immunologic+and+hematopoietic+function+of+mice.">Effects of Vicatia thibertica de boiss on immunologic and hematopoietic function of mice.</a> J Dali Univ. 2 (02), 6-10 (2017).</li><li>Dong, S., Zhang, X., Hu, Y., Gong, X., Yang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+constituents,+quality+control+and+pharmacology+research+progress+of+Xigui.">Chemical constituents, quality control and pharmacology research progress of Xigui.</a> Chin J Ethnomed Ethnopharm. 27 (13), 40-42 (2018).</li><li>Lu, Z., Zhang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+total+flavone+extract+from+Shuiqin+(Oenanthe+Javanica)+on+immune+function+of+immunosuppression+mice.">Effects of total flavone extract from Shuiqin (Oenanthe Javanica) on immune function of immunosuppression mice.</a> Chin J Trad Med Sci Technol. 23 (04), 423-425 (2016).</li><li>Vonderheide, R. 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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IFN&#947;+and+CCL2+cooperate+to+redirect+tumor-infiltrating+monocytes+to+degrade+fibrosis+and+enhance+chemotherapy+efficacy+in+pancreatic+carcinoma.">IFN&#947; and CCL2 cooperate to redirect tumor-infiltrating monocytes to degrade fibrosis and enhance chemotherapy efficacy in pancreatic carcinoma.</a> Cancer Discov. 6 (4), 400-413 (2016).</li><li>He, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+roles+of+regulatory+B+cells+in+cancer.">The roles of regulatory B cells in cancer.</a> J Immunol Res. 2014, 215471 (2014).</li><li>Eliopoulos, A. 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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-density+miniaturized+thermal+shift+assays+as+a+general+strategy+for+drug+discovery.">High-density miniaturized thermal shift assays as a general strategy for drug discovery.</a> J Biomol Screen. 6 (6), 429-440 (2001).</li><li>Gorny, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+nano-differential+scanning+fluorimetry+and+microscale+thermophoresis+to+investigate+VDAC1+interaction+with+small+molecules.">Combining nano-differential scanning fluorimetry and microscale thermophoresis to investigate VDAC1 interaction with small molecules.</a> J EnzymeInhib Med Chem. 38 (1), 2121821 (2023).</li><li>Freire, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+denaturation+methods+in+the+study+of+protein+folding.">Thermal denaturation methods in the study of protein folding.</a> Methods Enzymol. 259, 144-168 (1995).</li><li>Phiri, M. J., Mofokeng, J. P., Phiri, M. M., Mngomezulu, M., Tywabi-Ngeva, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical,+thermal+and+morphological+properties+of+polybutylene+succinate-waste+pineapple+leaf+fibres+composites.">Chemical, thermal and morphological properties of polybutylene succinate-waste pineapple leaf fibres composites.</a> Heliyon. 9 (11), 21238 (2023).</li><li>Zhou, C., Yu, M., Li, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparation+of+three+measuring+methods+for+thermodynamic+stability+of+protein.">Comparation of three measuring methods for thermodynamic stability of protein.</a> Anal Test Technol Instruments. 27 (04), 252-259 (2021).</li><li>Hou, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salidroside+intensifies+mitochondrial+function+of+CoCl2-damaged+HT22+cells+by+stimulating+PI3K-AKT-MAPK+signaling+pathway.">Salidroside intensifies mitochondrial function of CoCl2-damaged HT22 cells by stimulating PI3K-AKT-MAPK signaling pathway.</a> Phytomedicine. 109, 154568 (2023).</li><li>Wang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salidroside,+a+phenyl+ethanol+glycoside+from+Rhodiola+crenulata,+orchestrates+hypoxic+mitochondrial+dynamics+homeostasis+by+stimulating+Sirt1/p53/Drp1+signaling.">Salidroside, a phenyl ethanol glycoside from Rhodiola crenulata, orchestrates hypoxic mitochondrial dynamics homeostasis by stimulating Sirt1/p53/Drp1 signaling.</a> J Ethnopharmacol. 293, 115278 (2022).</li><li>Magnez, R., Bailly, C., Thuru, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microscale+thermophoresis+as+a+tool+to+study+protein+interactions+and+their+implication+in+human+diseases.">Microscale thermophoresis as a tool to study protein interactions and their implication in human diseases.</a> Int J Mol Sci. 23 (14), 7672 (2022).</li><li>Kamat, V., Rafique, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Designing+binding+kinetic+assay+on+the+bio-layer+interferometry+(BLI)+biosensor+to+characterize+antibody-antigen+interactions.">Designing binding kinetic assay on the bio-layer interferometry (BLI) biosensor to characterize antibody-antigen interactions.</a> Anal Biochem. 536, 16-31 (2017).</li><li>Freyer, M. 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The authors have nothing to disclose.

DSF, also known as the thermal shift assay or thermal fluorescence assay, is a technique employed to detect the process of thermal denaturation of proteins in samples by monitoring changes in the fluorescence signal of the test sample or dye during a slow, programmed temperature increase. Initially established by Pantoliano14, DSF serves as a high-throughput method. The main procedure involves elevating the temperature on a computer-controlled heated plate, emitting excitation light using a long-wavelength ultraviolet lamp, and capturing changes in fluorescent signal intensity resulting from the binding of fluorescent dyes to proteins through a charge-coupled device phase-forming camera.
The Tm value, a crucial indicator characterizing the higher-level structure of proteins, represents the temperature corresponding to half of the denaturation of the protein drug during a temperature increase. Higher Tm values suggest a greater temperature requirement for protein denaturation, indicating a more stable protein structure. The currently recognized method for detecting Tm values is differential scanning calorimetry (DSC), which was initiated in the 1960s15. DSC measures the difference in power delivered to the object being tested and a reference object as a function of temperature under programmed temperature control to obtain the amount of heat absorbed and discharged. It stands as the gold standard for thermal stability analysis16,17.
DSF has gained widespread use due to three advantages over DSC: (1) Less sample consumption: DSC typically requires a sample volume of 400 &#181;L, while DSF requires only 20-25 &#181;L. (2) Larger concentration range: DSC generally requires protein concentrations of 0.2-2 mg/mL to obtain a significant denaturation peak, whereas DSF can analyze samples in the range of 0.005-200 mg/mL. (3) Higher sample throughput: DSC can analyze only one sample at a time, while DSF can simultaneously scan up to 96 or more samples18. Due to these advantages, DSF is widely utilized in the study of protein stability, protein structure and conformation, protein-ligand interactions, and the effects of protein stabilizers, inhibitors, cofactors, and more.
In addition to DSF and DSC, several other molecular interaction techniques exist. Surface plasmon resonance (SPR) is an optical phenomenon occurring at the interface of two media and can be induced by photons or electrons. It involves total reflection when light is emitted from an optically dense medium into an optically sparse medium. The angle at which surface plasmon resonance occurs is known as the SPR angle. SPR biosensors utilize changes in SPR angles to monitor intermolecular interactions in real-time19,20. MicroScale thermophoresis (MST) is a technique for analyzing biomolecular interactions by detecting changes in the size, charge, and hydration layer of biomolecules caused by binding. It records fluorescence changes in the region irradiated by an infrared laser inside the sample before, during, and after the laser is turned on, allowing for relatively rapid determinations21. Bio-layer interferometry (BLI) measures sensor surface reactions by tracking displacement changes in the interferometry spectrum. In BLI experiments, one molecule is immobilized on the surface of a submersible sensor to detect another molecule that can bind to it. The binding interaction induces interference displacement, and real-time monitoring of this displacement change yields the binding curve22. Isothermal titration calorimetry (ITC) quantifies biomolecular interactions by directly measuring the heat released or absorbed during biomolecular binding. It provides comprehensive thermodynamic information about molecular interactions23. Compared to these molecular interaction technologies, DSF has lower requirements for instruments, consumables, and operating techniques. It can efficiently detect interactions between compounds and proteins in most laboratories.
The operational procedure of DSF technology is relatively straightforward. Initially, white matter samples, reaction buffers, fluorescent dyes, and candidate ligands are combined into a reaction system. This system is then transferred to a fluorescence PCR instrument where heating and detection conditions for fluorescence determination are set up24,25. The most commonly used protein-dye for DSF is currently orange dye, and the detection instrument is typically a fluorescence quantitative PCR instrument26. However, due to the excitation wavelength of orange dye being 470 nm and the emission wavelength being 570 nm, not all fluorescence quantitative PCR instruments on the market are a perfect match. Therefore, this study adopts a fluorescent microplate reader as a new detection instrument to explore protein-ligand interactions.
This approach offers two main advantages over DSF using a fluorescent quantitative PCR instrument. Firstly, the wavelength range of the fluorescent enzyme marker can be customized, making it more compatible with the dye&#39;s wavelength range and ensuring more accurate fluorescence detection. Secondly, the program of a fluorescence quantitative PCR instrument cannot be stopped once initiated, making it challenging to troubleshoot any problems during the heating process. In contrast, a fluorescent microplate reader allows for the elimination of interference by iteratively modifying the system ratio and detection conditions throughout the detection process. However, the use of a fluorescent microplate reader for DSF also comes with certain disadvantages, notably the relatively large amount of sample required, typically ranging from 50-200 &#181;L, while traditional DSF typically utilizes 20-25 &#181;L of sample.
In this article, the validation of DSF based on a fluorescent microplate reader was conducted for detecting Tm using CD40 protein and umbelliferone within the concentration range of 5-20 &#181;g/mL. The results demonstrated the method&#39;s high specificity and accuracy, affirming its suitability for Tm detection. Subsequent comparison of Tm detection results at different sample concentrations revealed a decreasing trend in the Tm value of CD40 protein as the concentration increased, suggesting a potential concentration effect on Tm detection (Figure 3). Furthermore, the study detected an increase in the Tm value of CD40 protein after the addition of umbelliferone to the system compared to before the addition. This indicates that umbelliferone possesses the ability to bind to CD40 protein, leading to an enhancement in the thermal stability of CD40 protein upon their combination (Figure 3).
The critical steps in the protocol were identified as steps 2.7 to 2.16, the successful completion of which directly influences the subsequent detection of protein fluorescence. In summary, this study established a novel DSF detection method based on DSF technology principles, utilizing CD40 protein and umbelliferone as an example. The method effectively analyzed the binding force between proteins and ligands using a fluorescent microplate reader. Furthermore, this technique can be extended for the analysis of protein stability and research into protein structure, deepening the application of DSF technology in studying cell signaling pathways and exploring disease pathogenesis.

Vicatia thibetica H. Boissieu, a plant in the umbelliferous family, is commonly used in Tibetan medicine and represents one of the essential components of the five basic ingredients (Polygonatum sibiricum Delar. ex Redoute, Asparagus cochinchinensis (Lour.) Merr, Vicatia thibetica H. Boissieu, Oxybaphus himalaicus Edgew., and Gymnadenia conopsea (L.) R. Br.)1. Mainly distributed in southwest China, such as northwest Yunnan, western Sichuan, Tibet, and other areas, its dried root serves as a local substitute for Angelica1. The root, known for its fragrance, is often utilized as a stew seasoning, and the leaves, referred to as Tibetan celery, contribute to delectable dishes. Thus, Vicatia thibetica holds significance not only as a unique medicinal plant but also as a food source in Tibet.
Both domestic and international research indicates that Vicatia thibetica possesses blood-replenishing and qi (power or energy)-invigorating properties, beneficial for regulating menstruation. It is employed to address symptoms of irregular menstrual dysmenorrhea caused by palpitation and blood deficiency, exhibiting pharmacological effects such as antioxidant regulation of body immunity2. The alcohol extract of Vicatia thibetica has demonstrated the ability to restore body mass and organ index in immunocompromised mice induced by cyclophosphamide. Additionally, it increases the activity of superoxide dismutase in serum and reduces the content of malondialdehyde, suggesting an improvement in antioxidant capacity and a balancing effect on lipid peroxidation2,3. Simultaneously, it enhances the number of blood cells and hemoglobin, which not only objectively reflects the body&#39;s hematopoietic function but also plays a crucial role in the immune system2,3.
Umbelliferone, characterized by acicular crystals and a bitter taste, possesses a small molecular weight, is volatile, and can be distilled with steam. It sublimates easily, has low solubility in water, and high solubility in organic matter. As one of the main chemical components of Vicatia thibetica, umbelliferone exhibits immunomodulatory effects on cellular immunity, humoral immunity, and non-specific immunity in hydrocortisone-induced immunosuppression mouse models4,5.
The cell surface molecule CD40, a member of the tumor necrosis factor receptor superfamily, is widely expressed in immune cells6. Its homologous ligand, CD154, also known as CD40L, is a type II transmembrane protein expressed by activated T lymphocytes. CD40 activation has the capacity to up-regulate the expression of co-stimulatory molecules on the surface of dendritic cells (DC) and monocytes. This process promotes the antigen presentation function of major histocompatibility complex (MHC) molecules and further activates CD8+ T cells7.
Macrophages play a crucial role in the formation and regulation of the tumor microenvironment, and CD40 activation can enhance the remodeling of the tumor microenvironment by macrophages8. CD40 signal activation significantly influences the proliferation and activation of B cells. B cells, when activated by CD40, can function as effective antigen-presenting cells. They present antigens, generate effector T cell activity, and thereby contribute to anti-tumor effects9. Moreover, CD40 activation in tumor cells can induce apoptosis and inhibit tumor growth10. CD40 primarily transduces signals by controlling the activity of non-receptor tyrosine protein kinases, including Lyn, Fyn, Syk, and others. Additionally, it has the ability to stimulate Bcl-xL, Cdk4, and Cdk6 proteins, activate Rel/NF-kB transcription factors, and phosphorylate CG-2 and PI3K10.
The Differential Scanning Fluorescence (DSF) method is widely employed to assess the impact of various environmental conditions, such as buffer composition, temperature, and small molecule ligands, on the thermal stability of protein structures. The commonly utilized dye for DSF is an orange, environmentally sensitive, hydrophobic dye. Under normal conditions, the protein structure is folded, concealing its hydrophobic segment internally. As the temperature increases, the protein&#39;s hydrophobic region becomes more exposed, resulting in a gradual breakdown of the natural protein structure. The dye selectively binds to this exposed protein portion, amplifying its fluorescence. Tm values are then calculated by monitoring changes in the fluorescence signal detection11. To a certain extent, variations in Tm values can gauge shifts in protein stability due to mutations, changes in buffers, or ligand binding. Furthermore, it can indicate structural alterations during the protein folding process12. This approach offers precise data, a broad temperature range, high sensitivity, and minimal protein sample loss13.
In this study, fluorescence determination was conducted using a fluorescent microplate reader instead of a fluorescence quantitative polymerase chain reaction (PCR) apparatus. This modification enables DSF detection in laboratories lacking a fluorescent quantitative PCR instrument, making the method less complex and reducing the steps required for instrument setup, thereby simplifying the experimental process. However, there are certain drawbacks to this approach. While the complexity is reduced, the procedure becomes more cumbersome. Manual fluorescence detection at different temperatures is necessary, and automatic and continuous collection of fluorescence from the system cannot be achieved. Thus, this study utilized the DSF technique to explore the interaction between CD40 protein and umbelliferone, providing novel insights into the molecular mechanisms of Tibetan medicine.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>CD40 protein</td>
			<td>MedChemExpress</td>
			<td>HY-P75408</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Boster Biological Technology Co., Ltd</td>
			<td>PYG0040</td>
			<td></td>
		</tr>
		<tr>
			<td>FlexStation 3 multifunctional microplate reader</td>
			<td>Shanghai Meigu Molecular Instruments Co., LTD</td>
			<td>FlexStation 3</td>
			<td></td>
		</tr>
		<tr>
			<td>OriginPro 8 software</td>
			<td>OriginLab Corporation</td>
			<td>v8.0724(B724)</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (1x)</td>
			<td>Gibco</td>
			<td>8120485</td>
			<td></td>
		</tr>
		<tr>
			<td>SoftMax Pro 7.1</td>
			<td>Shanghai Meigu Molecular Instruments Co., LTD</td>
			<td>SoftMax Pro 7.1</td>
			<td></td>
		</tr>
		<tr>
			<td>SSYPRO orange dye</td>
			<td>Sigma</td>
			<td>S5942</td>
			<td></td>
		</tr>
		<tr>
			<td>Umbelliferone</td>
			<td>Shanghai Yuanye Biotechnology Co.</td>
			<td>B21854</td>
			<td></td>
		</tr>
	</tbody>
</table>

detection of cd40 protein-umbelliferone interaction via differential scanning fluorescence

The investigation of interactions between different molecules is a crucial aspect of understanding disease pathogenesis and screening for drug targets. Umbelliferone, an active ingredient in Tibetan medicine Vicatia thibetica, exhibits an immunomodulatory effect with an unknown mechanism. The CD40 protein is a key target in the immune response. Therefore, this study employs the principle of differential scanning fluorescence technology to analyze the interactions between CD40 protein and umbelliferone using fluorescent enzyme markers. Initially, the stability of the protein fluorescent orange dye was experimentally verified, and the optimal dilution ratio of 1:500 was determined. Subsequently, it was observed that the temperature melting (Tm) value of CD40 protein tended to decrease with an increase in concentration. Interestingly, the interaction between CD40 protein and umbelliferone was found to enhance the thermal stability of CD40 protein. This study represents the first attempt to detect the binding potential of small molecule compounds and proteins using fluorescence microplates and fluorescent dyes. The technique is characterized by high sensitivity and accuracy, promising advancements in the fields of protein stability, protein structure, and protein-ligand interactions, thus facilitating further research and exploration.

The orange dye consistently exhibited stable fluorescence excitation at Ex = 470 nm and Em = 570 nm, both at room temperature and elevated temperatures. An optimal dilution ratio of 1:500 was determined (Figure 2A,B). Detection of the Tm value proved challenging when the concentration of CD40 protein was below 15 &#181;g/mL (Figure 3A,B). However, at a concentration of 15 &#181;g/mL, a stable Tm value of 51.82 &#176;C was detectable, which decreased to 45.79 &#176;C with an increase in CD40 protein concentration (Figure 3C,D).

As depicted in Figure 3, it is evident that CD40 protein binding to umbelliferone influences the Tm value of CD40 protein. Specifically, Tm values of CD40 protein at concentrations of 15 &#181;g/mL and 20 &#181;g/mL, as well as 10 &#181;M umbelliferone, increased to 62.08 &#176;C and 65.27 &#176;C, respectively.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66610/66610fig1.jpg" /> 
Figure 1: Overview of the protocol. Flowchart of the process of recording the binding capacity of CD40 protein to umbelliferone based on the DSF principle using a fluorescent microplate reader. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66610/66610fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66610/66610fig2.jpg" /> 
Figure 2: Screening of orange dye dilution ratios and stability tests. (A) Fluorescence stability of dyes with different dilution ratios at room temperature. (B) Fluorescence stability of dyes with a dilution ratio of 1:500 at 35-95 &#176;C. The error bars denote mean &#177; SEM, n = 4. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66610/66610fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66610/66610fig3.jpg" /> 
Figure 3: Result plots of using a fluorescent microplate reader to record the binding capacity of CD40 protein to umbelliferone according to the DSF principle. (A-D) Tm Profiles of 5 &#181;g/mL, 10 &#181;g/mL, 15 &#181;g/mL, 20 &#181;g/mL CD40 Protein and CD40 + 10 &#181;M umbelliferone, respectively. The error bars denote mean &#177; SEM, n = 4. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66610/66610fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Author Spotlight: Streamlining PCR Methods for Enhanced Accessibility and Efficiency at JoVE.com

Author Spotlight: Streamlining PCR Methods for Enhanced Accessibility and Efficiency

This protocol describes a unique method for detecting the binding between compounds and protein molecules, offering the advantages of minimal protein sample loss and high data accuracy.

Detection of CD40 Protein-Umbelliferone Interaction via Differential Scanning Fluorescence

The investigation of interactions between different molecules is a crucial aspect of understanding disease pathogenesis and screening for drug targets. ...

detection-cd40-protein-umbelliferone-interaction-via-differential

Nanyang Technological University

Research

JoVE Journal

Medicine

391 Views.  University of Tibetan Medicine. This protocol describes a unique method for detecting the binding between compounds and protein molecules, offering the advantages of minimal protein sample loss and high data accuracy.

Video: Author Spotlight: Streamlining PCR Methods for Enhanced Accessibility and Efficiency

Multispectral Real-time Fluorescence Imaging for Intraoperative Detection of the Sentinel Lymph Node in Gynecologic Oncology

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical excision of the tumor with a full lymphadenectomy in the drainage area of the tumor. However, removal of lymph nodes is associated with increased morbidity due to infection, wound breakdown and lymphedema.4,5 As an alternative, the sentinel lymph node procedure (SLN) was developed several decades ago to detect the first draining lymph node from the tumor.6 In case of lymphogenic dissemination, the SLN is the first lymph node that is affected (Figure 1). Hence, if the SLN does not contain metastases, downstream lymph nodes will also be free from tumor metastases and need not to be removed. The SLN procedure is part of the treatment for many tumor types, like breast cancer and melanoma, but also for cancer of the vulva and cervix.7 The current standard methodology for SLN-detection is by peritumoral injection of radiocolloid one day prior to surgery, and a colored dye intraoperatively. Disadvantages of the procedure in cervical and vulvar cancer are multiple injections in the genital area, leading to increased psychological distress for the patient, and the use of radioactive colloid.
Multispectral fluorescence imaging is an emerging imaging modality that can be applied intraoperatively without the need for injection of radiocolloid. For intraoperative fluorescence imaging, two components are needed: a fluorescent agent and a quantitative optical system for intraoperative imaging. As a fluorophore we have used indocyanine green (ICG). ICG has been used for many decades to assess cardiac function, cerebral perfusion and liver perfusion.8 It is an inert drug with a safe pharmaco-biological profile. When excited at around 750 nm, it emits light in the near-infrared spectrum around 800 nm. A custom-made multispectral fluorescence imaging camera system was used.9.
The aim of this video article is to demonstrate the detection of the SLN using intraoperative fluorescence imaging in patients with cervical and vulvar cancer. Fluorescence imaging is used in conjunction with the standard procedure, consisting of radiocolloid and a blue dye. In the future, intraoperative fluorescence imaging might replace the current method and is also easily transferable to other indications like breast cancer and melanoma.

Fluorescence imaging is a promising innovative modality for image-guided surgery in surgical oncology. In this video we describe the technical procedure for detection of the sentinel lymph node using fluorescence imaging as showcased in gynecologic oncologicy. A multispectral fluorescence camera system, together with the fluorescent agent indocyanine green, is applied.

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical ...

Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy

Confocal laser scanning microscopy (CLSM) of natural heterogeneous biofilm is today facilitated by a comprehensive range of staining techniques, one of them being fluorescence in situ hybridization (FISH).1,2 We performed a pilot study in which oral biofilm samples collected from fixed orthodontic appliances (palatal expanders) were stained by FISH, the objective being to assess the three-dimensional organization of natural biofilm and plaque accumulation.3,4 FISH creates an opportunity to stain cells in their native biofilm environment by the use of fluorescently labeled 16S rRNA-targeting probes.4-7,19 Compared to alternative techniques like immunofluorescent labeling, this is an inexpensive, precise and straightforward labeling technique to investigate different bacterial groups in mixed biofilm consortia.18,20 General probes were used that bind to Eubacteria (EUB338 + EUB338II + EUB338III; hereafter EUBmix),8-10 Firmicutes (LGC354 A-C; hereafter LGCmix),9,10 and Bacteroidetes (Bac303).11 In addition, specific probes binding to Streptococcus mutans (MUT590)12,13 and Porphyromonas gingivalis (POGI)13,14 were used. The extreme hardness of the surface materials involved (stainless steel and acrylic resin) compelled us to find new ways of preparing the biofilm. As these surface materials could not be readily cut with a cryotome, various sampling methods were explored to obtain intact oral biofilm. The most workable of these approaches is presented in this communication. Small flakes of the biofilm-carrying acrylic resin were scraped off with a sterile scalpel, taking care not to damage the biofilm structure. Forceps were used to collect biofilm from the steel surfaces. Once collected, the samples were fixed and placed directly on polysine coated glass slides. FISH was performed directly on these slides with the probes mentioned above. Various FISH protocols were combined and modified to create a new protocol that was easy to handle.5,10,14,15 Subsequently the samples were analyzed by confocal laser scanning microscopy. Well-known configurations3,4,16,17 could be visualized, including mushroom-style formations and clusters of coccoid bacteria pervaded by channels. In addition, the bacterial composition of these typical biofilm structures were analyzed and 2D and 3D images created.

We present a protocol for structural and compositional analysis of natural oral biofilm from orthodontic appliances with in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). Oral biofilm samples were collected from palatal expanders, scraping acrylic-resin flakes off their surface and referring them for molecular processing.

Confocal laser scanning microscopy (CLSM) of natural heterogeneous biofilm is today facilitated by a comprehensive range of staining techniques, one of ...

Experimental Generation of Carcinoma-Associated Fibroblasts (CAFs) from Human Mammary Fibroblasts

Carcinomas are complex tissues comprised of neoplastic cells and a non-cancerous compartment referred to as the 'stroma'. The stroma consists of extracellular matrix (ECM) and a variety of mesenchymal cells, including fibroblasts, myofibroblasts, endothelial cells, pericytes and leukocytes 1-3.
The tumour-associated stroma is responsive to substantial paracrine signals released by neighbouring carcinoma cells. During the disease process, the stroma often becomes populated by carcinoma-associated fibroblasts (CAFs) including large numbers of myofibroblasts. These cells have previously been extracted from many different types of human carcinomas for their in vitro culture. A subpopulation of CAFs is distinguishable through their up-regulation of &alpha;-smooth muscle actin (&alpha;-SMA) expression4,5. These cells are a hallmark of 'activated fibroblasts' that share similar properties with myofibroblasts commonly observed in injured and fibrotic tissues 6. The presence of this myofibroblastic CAF subset is highly related to high-grade malignancies and associated with poor prognoses in patients.
Many laboratories, including our own, have shown that CAFs, when injected with carcinoma cells into immunodeficient mice, are capable of substantially promoting tumourigenesis 7-10. CAFs prepared from carcinoma patients, however, frequently undergo senescence during propagation in culture limiting the extensiveness of their use throughout ongoing experimentation. To overcome this difficulty, we developed a novel technique to experimentally generate immortalised human mammary CAF cell lines (exp-CAFs) from human mammary fibroblasts, using a coimplantation breast tumour xenograft model.
In order to generate exp-CAFs, parental human mammary fibroblasts, obtained from the reduction mammoplasty tissue, were first immortalised with hTERT, the catalytic subunit of the telomerase holoenzyme, and engineered to express GFP and a puromycin resistance gene. These cells were coimplanted with MCF-7 human breast carcinoma cells expressing an activated ras oncogene (MCF-7-ras cells) into a mouse xenograft. After a period of incubation in vivo, the initially injected human mammary fibroblasts were extracted from the tumour xenografts on the basis of their puromycin resistance 11.
We observed that the resident human mammary fibroblasts have differentiated, adopting a myofibroblastic phenotype and acquired tumour-promoting properties during the course of tumour progression. Importantly, these cells, defined as exp-CAFs, closely mimic the tumour-promoting myofibroblastic phenotype of CAFs isolated from breast carcinomas dissected from patients. Our tumour xenograft-derived exp-CAFs therefore provide an effective model to study the biology of CAFs in human breast carcinomas. The described protocol may also be extended for generating and characterising various CAF populations derived from other types of human carcinomas.

Experimental Generation of Carcinoma-Associated Fibroblasts CAFs from Human Mammary Fibroblasts

Carcinoma-associated fibroblasts (CAFs) rich in myofibroblasts present within the tumour stroma, play a major role in driving tumour progression. We developed a coimplantation tumour xengraft model for experimentally generating CAFs from human mammary fibroblasts. The protocol describes how to establish CAF myofibroblasts that acquire an ability to promote tumourigenesis.

Carcinomas are complex tissues comprised of neoplastic cells and a non-cancerous compartment referred to as the 'stroma'. The stroma consists of ...

NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited for studies of cardiac metabolism, which require the heart to perform work within the context of physiologic preload and afterload pressures. Neely introduced modifications to the Langendorff technique to establish appropriate left ventricular (LV) preload and afterload pressures3. The model is known as the isolated LV working heart model and has been used extensively to study LV performance and metabolism4-6. This model, however, does not provide a properly loaded right ventricle (RV). Demmy et al. first reported a biventricular model as a modification of the LV working heart model7, 8. They found that stroke volume, cardiac output, and pressure development improved in hearts converted from working LV mode to biventricular working mode8. A properly loaded RV also diminishes abnormal pressure gradients across the septum to improve septal function. Biventricular working hearts have been shown to maintain aortic output, pulmonary flow, mean aortic pressure, heart rate, and myocardial ATP levels for up to 3 hours8.
When studying the metabolic effects of myocardial injury, such as ischemia, it is often necessary to identify the location of the affected tissue. This can be done by imaging the fluorescence of NADH (the reduced form of nicotinamide adenine dinucleotide)9-11, a coenzyme found in large quantities in the mitochondria. NADH fluorescence (fNADH) displays a near linearly inverse relationship with local oxygen concentration12 and provides a measure of mitochondrial redox state13. fNADH imaging during hypoxic and ischemic conditions has been used as a dye-free method to identify hypoxic regions14, 15 and to monitor the progression of hypoxic conditions over time10.
The objective of the method is to monitor the mitochondrial redox state of biventricular working hearts during protocols that alter the rate of myocyte metabolism or induce hypoxia or create a combination of the two. Hearts from New Zealand white rabbits were connected to a biventricular working heart system (Hugo Sachs Elektronik) and perfused with modified Krebs-Henseleit solution16 at 37 &deg;C. Aortic, LV, pulmonary artery, and left &amp; right atrial pressures were recorded. Electrical activity was measured using a monophasic action potential electrode. To image fNADH, light from a mercury lamp was filtered (350&plusmn;25 nm) and used to illuminate the epicardium. Emitted light was filtered (460&plusmn;20 nm) and imaged using a CCD camera. Changes in the epicardial fNADH of biventricular working hearts during different pacing rates are presented. The combination of the heart model and fNADH imaging provides a new and valuable experimental tool for studying acute cardiac pathologies within the context of realistic physiological conditions.

The objective is to monitor the mitochondrial redox state of isolated hearts within the context of physiologic preload and afterload pressures. A biventricular working rabbit heart model is presented. High spatiotemporal resolution fluorescence imaging of NADH is used to monitor the mitochondrial redox state of epicardial tissue.

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited ...

Intraoperative Detection of Subtle Endometriosis: A Novel Paradigm for Detection and Treatment of Pelvic Pain Associated with the Loss of Peritoneal Integrity

Endometriosis is a common disease affecting 40 to 70% of reproductive-aged women with chronic pelvic pain (CPP) and/or infertility. The purpose of this study was to demonstrate the use of a blue dye (methylene blue) to stain peritoneal surfaces during laparoscopy (L/S) to detect the loss of peritoneal integrity in patients with pelvic pain and suspected endometriosis. Forty women with CPP and 5 women without pain were evaluated in this pilot study. During L/S, concentrated dye was sprayed onto peritoneal surfaces, then aspirated and rinsed with Lactated Ringers solution. Areas of localized dye uptake were evaluated for the presence of visible endometriotic lesions. Areas of intense peritoneal staining were resected and some fixed in 2.5% buffered gluteraldehyde and examined by scanning (SEM) electron microscopy. Blue dye uptake was more common in women with endometriosis and chronic pelvic pain than controls (85% vs. 40%). Resection of the blue stained areas revealed endometriosis by SEM and loss of peritoneal cell-cell contact compared to normal, non-staining peritoneum. Affected peritoneum was associated with visible endometriotic implants in most but not all patients. Subjective pain relief was reported in 80% of subjects. Based on scanning electron microscopy, we conclude that endometrial cells extend well beyond visible implants of endometriosis and appear to disrupt the underlying mesothelium. Subtle lesions of endometriosis could therefore cause pelvic pain by disruption of peritoneal integrity, allowing menstrual or ovulatory blood and associated pain factors access to underlying sensory nerves. Complete resection of affected peritoneum may provide a better long-term treatment for endometriosis and CPP. This simple technique appears to improve detection of subtle or near invisible endometriosis in women with CPP and minimal visual findings at L/S and may serve to elevate diagnostic accuracy for endometriosis at laparoscopy.

Loss of peritoneal integrity provides a new paradigm to understand and treat chronic pelvic pain in women with mild forms of endometriosis and can be easily detected using intraoperative instillation of dye at the time of laparoscopy.

Endometriosis is a  common disease affecting 40 to 70% of reproductive-aged women with chronic  pelvic pain (CPP) and/or infertility. The purpose of this ...

Cerenkov Luminescence Imaging (CLI) for Cancer Therapy Monitoring

In molecular imaging, positron emission tomography (PET) and optical imaging (OI) are two of the most important and thus most widely used modalities1-3. PET is characterized by its excellent sensitivity and quantification ability while OI is notable for non-radiation, relative low cost, short scanning time, high throughput, and wide availability to basic researchers. However, both modalities have their shortcomings as well. PET suffers from poor spatial resolution and high cost, while OI is mostly limited to preclinical applications because of its limited tissue penetration along with prominent scattering optical signals through the thickness of living tissues.
 Recently a bridge between PET and OI has emerged with the discovery of Cerenkov Luminescence Imaging (CLI)4-6. CLI is a new imaging modality that harnesses Cerenkov Radiation (CR) to image radionuclides with OI instruments. Russian Nobel laureate Alekseyevich Cerenkov and his colleagues originally discovered CR in 1934. It is a form of electromagnetic radiation emitted when a charged particle travels at a superluminal speed in a dielectric medium7,8. The charged particle, whether positron or electron, perturbs the electromagnetic field of the medium by displacing the electrons in its atoms. After passing of the disruption photons are emitted as the displaced electrons return to the ground state. For instance, one 18F decay was estimated to produce an average of 3 photons in water5. 
 Since its emergence, CLI has been investigated for its use in a variety of preclinical applications including in vivo tumor imaging, reporter gene imaging, radiotracer development, multimodality imaging, among others4,5,9,10,11. The most important reason why CLI has enjoyed much success so far is that this new technology takes advantage of the low cost and wide availability of OI to image radionuclides, which used to be imaged only by more expensive and less available nuclear imaging modalities such as PET.
 Here, we present the method of using CLI to monitor cancer drug therapy. Our group has recently investigated this new application and validated its feasibility by a proof-of-concept study12. We demonstrated that CLI and PET exhibited excellent correlations across different tumor xenografts and imaging probes. This is consistent with the overarching principle of CR that CLI essentially visualizes the same radionuclides as PET. We selected Bevacizumab (Avastin; Genentech/Roche) as our therapeutic agent because it is a well-known angiogenesis inhibitor13,14. Maturation of this technology in the near future can be envisioned to have a significant impact on preclinical drug development, screening, as well as therapy monitoring of patients receiving treatments.

Cerenkov Luminescence Imaging CLI for Cancer Therapy Monitoring

Use of Cerenkov Luminescence Imaging (CLI) for monitoring preclinical cancer treatment is described here. This method takes advantage of Cerenkov Radiation (CR) and optical imaging (OI) to visualize radiolabeled probes and thus provides an alternative to PET in preclinical therapeutic monitoring and drug screening.

In  molecular imaging, positron emission tomography (PET) and optical imaging (OI)  are two of the most important and thus most widely used modalities1-3. ...

Detection of Architectural Distortion in Prior Mammograms via Analysis of Oriented Patterns

We demonstrate methods for the detection of architectural distortion in prior mammograms of interval-cancer cases based on analysis of the orientation of breast tissue patterns in mammograms. We hypothesize that architectural distortion modifies the normal orientation of breast tissue patterns in mammographic images before the formation of masses or tumors. In the initial steps of our methods, the oriented structures in a given mammogram are analyzed using Gabor filters and phase portraits to detect node-like sites of radiating or intersecting tissue patterns. Each detected site is then characterized using the node value, fractal dimension, and a measure of angular dispersion specifically designed to represent spiculating patterns associated with architectural distortion.
Our methods were tested with a database of 106 prior mammograms of 56 interval-cancer cases and 52 mammograms of 13 normal cases using the features developed for the characterization of architectural distortion, pattern classification via quadratic discriminant analysis, and validation with the leave-one-patient out procedure. According to the results of free-response receiver operating characteristic analysis, our methods have demonstrated the capability to detect architectural distortion in prior mammograms, taken 15 months (on the average) before clinical diagnosis of breast cancer, with a sensitivity of 80% at about five false positives per patient.

Detection of Architectural Distortion in Prior Mammograms via Analysis of Oriented Patterns

We demonstrate methods for the detection of architectural distortion in prior mammograms. Oriented structures are analyzed using Gabor filters and phase portraits to detect sites of radiating tissue patterns. Each site is characterized and classified using measures to represent spiculating patterns. The methods should assist in the detection of breast cancer.

We demonstrate methods for the detection of architectural distortion in prior mammograms of interval-cancer cases based on analysis of the orientation of ...

Three-dimensional Co-culture Model for Tumor-stromal Interaction

Cancer progression (initiation, growth, invasion and metastasis) occurs through interactions between malignant cells and the surrounding tumor stromal cells. The tumor microenvironment is comprised of a variety of cell types, such as fibroblasts, immune cells, vascular endothelial cells, pericytes and bone-marrow-derived cells, embedded in the extracellular matrix (ECM). Cancer-associated fibroblasts (CAFs) have a pro-tumorigenic role through the secretion of soluble factors, angiogenesis and ECM remodeling. The experimental models for cancer cell survival, proliferation, migration, and invasion have mostly relied on two-dimensional monocellular and monolayer tissue cultures or Boyden chamber assays. However, these experiments do not precisely reflect the physiological or pathological conditions in a diseased organ. To gain a better understanding of tumor stromal or tumor matrix interactions, multicellular and three-dimensional cultures provide more powerful tools for investigating intercellular communication and ECM-dependent modulation of cancer cell behavior. As a platform for this type of study, we present an experimental model in which cancer cells are cultured on collagen gels embedded with primary cultures of CAFs.

Here we present a protocol to co-culture in three-dimensions, which is useful for investigating multicellular interactions and extracellular matrix-dependent modulation of cancer cell behavior. In this experimental model, cancer cells are cultured on collagen gels embedded with human cancer-associated fibroblasts.

Cancer progression (initiation, growth, invasion and metastasis) occurs through interactions between malignant cells and the surrounding tumor stromal ...

Fluorescence-mediated Tomography for the Detection and Quantification of Macrophage-related Murine Intestinal Inflammation

Murine models of disease are indispensable to scientific research. However, many diagnostic tools such as endoscopy or tomographic imaging are not routinely employed in animal models. Conventional experimental readouts often rely on post mortem and ex vivo analyses, which prevent intra-individual follow-up examinations and increase the number of study animals needed. Fluorescence-mediated tomography enables the non-invasive, repetitive, quantitative, three-dimensional assessment of fluorescent probes. It is highly sensitive and permits the use of molecular makers, which allows for the specific detection and characterization of distinct molecular targets. In particular, targeted probes represent an innovative tool for analyzing gene activation and protein expression in inflammation, autoimmune disease, infection, vascular disease, cell migration, tumorigenesis, etc. In this article, we provide step-by-step instructions on this sophisticated imaging technology for the in vivo detection and characterization of inflammation (i.e., F4/80-positive macrophage infiltration) in a widely used murine model of intestinal inflammation. This technique might also be used in other research areas, such as immune cell or stem cell tracking.

Target-specific probes represent an innovative tool for analyzing molecular mechanisms, such as protein expression in various types of disease (e.g., inflammation, infection, and tumorigenesis). In this study, we describe a quantitative three-dimensional tomographic assessment of intestinal macrophage infiltration in a murine model of colitis using F4/80-specific fluorescence-mediated tomography.

Murine models of disease are indispensable to scientific research. However, many diagnostic tools such as endoscopy or tomographic imaging are not ...

Differential Effects of Lipid-lowering Drugs in Modulating Morphology of Cholesterol Particles

Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to moderate level of increase in high-density lipoprotein (HDL) cholesterol in plasma. However, a possible role of these drugs in altering morphology and distribution of cholesterol particles is poorly understood. Here, we describe the in vitro evaluation of lipid-lowering drug effects in modulating morphological features of cholesterol particles using the plaque array method in combination with imaging flow cytometry. Image analyses of the cholesterol particles indicated that lovastatin, simvastatin, ezetimibe, and atorvastatin induce the formation of both globular and linear strand-shaped particles, whereas niacin, fibrates, fluvastatin, and rosuvastatin induce the formation of only globular-shaped particles. Next, purified very low-density lipoprotein (VLDL) and LDL particles incubated with these drugs showed changes in the morphology and image texture of cholesterol particles subpopulations. Furthermore, screening of 50 serum samples revealed the presence of a higher level of linear shaped HDL cholesterol particles in subjects with dyslipidemia (mean of 18.3%) compared to the age-matched normal (mean of 11.1%) samples. We also observed considerable variations in lipid-lowering drug effects on reducing linear shaped LDL and HDL cholesterol particles formation in serum samples. These findings indicate that lipid-lowering drugs, in addition to their cell-mediated hypolipidemic effects, may directly modulate morphology of cholesterol particles by a non-enzymatic mechanism of action. The outcomes of these results have potential to inform diagnosis of atherosclerosis and predict optimal lipid-lowering therapy.

The objective of this study was to evaluate in vitro lipid-lowering drug effects in modulating the morphology of cholesterol particles. Comparison of lipid-lowering drugs revealed variations in their effect in modulating the morphological features of cholesterol particles.