Candidalysin

The high-salt/hypotonic fractionation method for nuclear protein extraction is based on the differential solubility of cellular components. Cytoplasmic proteins are extracted first using a hypotonic buffer that causes cell swelling and membrane rupture, followed by centrifugation to separate the cytoplasmic supernatant from the nuclear pellet. The nuclear pellet is then subjected to high-salt extraction (e. g. , 0. 4 M (NH4)2SO4 or 1 M NaCl) to solubilize tightly bound nuclear matrix proteins, including transcription factors, histones, and structural proteins associated with chromatin and the nuclear scaffold. This approach allows for the isolation of both soluble cytoplasmic proteins and salt-resistant nuclear proteins while minimizing cross-contamination.

By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.

Mitochondrial membrane potential fluorescent assays estimate ΔΨm in living cells using lipophilic cationic dyes such as TMRM, TMRE, rhodamine 123, and JC-1, which accumulate in mitochondria according to membrane polarization; loss of signal after FCCP or CCCP treatment is interpreted as mitochondrial depolarization. TMRM/TMRE and rhodamine 123 are commonly used for semi-quantitative live-cell microscopy or flow cytometry, while JC-1 can report a shift from red aggregate fluorescence to green monomer fluorescence during depolarization; interpretation requires controls because dye concentration, quenching mode, cell type, dye efflux, and mitochondrial mass can affect fluorescence independently of ΔΨm.

Cytotoxicity assays are usually based on the assessment of cell membrane damage, which can also be indirectly detected by measuring cell viability. Detection methods include MTT assay, CKK-8 assay, LDH assay and ATP assay, etc.

Live/dead viability and cytotoxicity staining assays are based on the simultaneous detection of intracellular esterase activity in metabolically active (viable) cells and membrane integrity loss in non-viable cells. In commonly used dual-staining approaches, membrane-permeant fluorogenic substrates are converted by intracellular esterases into fluorescent products in live cells, while impermeant DNA-binding dyes selectively enter cells with compromised plasma membranes and label nucleic acids in dead or dying cells, enabling discrimination between viable and non-viable populations by fluorescence microscopy or flow cytometry.

Naïve CD4+ T-cell subset differentiation/polarization is an in vitro assay in which purified naïve CD4+ T cells are activated through TCR and CD28 costimulation and cultured with defined cytokines and neutralizing antibodies to generate Th0, Th1, Th2, Th17, or induced Treg-like populations. Differentiation is detected by subset-associated cytokines and transcription factors: IFN-γ/T-bet for Th1, IL-4/GATA3 for Th2, IL-17A/RORγt for Th17, and Foxp3 for induced Treg cells. The assay readout is usually generated by intracellular cytokine staining after restimulation, transcription-factor staining by flow cytometry, ELISA of secreted cytokines, or gene-expression analysis. The result reflects cytokine-directed lineage commitment or polarization rather than antigen-specific immune protection by itself.

Mitochondrial membrane potential staining measures the electrochemical polarization across the mitochondrial inner membrane in live cells using lipophilic cationic fluorescent probes; early rhodamine-based work showed that selective mitochondrial dye accumulation is lost when the mitochondrial transmembrane potential is dissipated. JC-1 reports mitochondrial polarization by shifting from green monomer fluorescence to red J-aggregate fluorescence as dye concentration increases within energized mitochondria; therefore, the red/green fluorescence ratio is used as a relative readout of mitochondrial membrane potential. TMRE or TMRM staining provides a single-channel relative readout because these cationic rhodamine esters accumulate in polarized mitochondria, and lower fluorescence indicates reduced mitochondrial polarization when acquisition and dye-loading conditions are controlled. Mitochondrial mass staining is commonly performed with MitoTracker Green FM or related MitoTracker dyes as

Zymosan-induced peritonitis is a sterile acute-inflammation model produced by intraperitoneal injection of zymosan, a yeast cell-wall particle preparation, followed by quantification of leukocyte recruitment and soluble inflammatory mediators in peritoneal lavage fluid. Low-dose zymosan peritonitis is commonly used as a self-resolving acute inflammation model in which neutrophil recruitment occurs early and monocyte/macrophage accumulation follows later. The assay readouts include total peritoneal leukocyte number, differential neutrophil and monocyte/macrophage counts, peritoneal cytokines and chemokines, plasma or peritoneal exudation, and optional lipidomic or metabolomic changes during inflammation and resolution. Early neutrophil recruitment after zymosan depends strongly on complement and mast-cell C5a receptor signaling, whereas later monocyte recruitment is linked to MCP-1/CCL2 production.

Ca²⁺ staining is an experimental technique that utilizes specific fluorescent probes (such as Fluo-4 AM, Fura-2, etc.) to qualitatively or quantitatively detect dynamic changes in intracellular Ca²⁺ concentrations; this is achieved by monitoring the changes in fluorescent signals generated when these probes bind to free intracellular calcium ions. The underlying principle relies primarily on the presence of chelating groups within the probe's molecular structure that possess high affinity for calcium ions.

The following protocol uses the MTT colorimetric assay as a classic literature-established method for assessing cell viability/metabolic activity in cultured mammalian cells. MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] is reduced by metabolically active cells to a colored formazan product; the amount of formazan is quantified spectrophotometrically and provides an indirect measure of metabolically active viable cells. Importantly, MTT reduction reflects cellular oxidoreductase/metabolic activity rather than an absolute direct count of living cells, so changes in cellular metabolism can alter the signal independently of cell number.