Tovophyllin A

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.

Annexin V-based apoptosis assays rely on the detection of phosphatidylserine (PS) externalization from the inner leaflet of the plasma membrane to the outer leaflet, an early biochemical hallmark of apoptosis. Fluorescently labeled Annexin V binds PS in a calcium-dependent manner, enabling identification of early apoptotic cells by flow cytometry or fluorescence microscopy. When combined with a membrane-impermeant DNA-binding dye (e. g. , propidium iodide), this approach allows discrimination between viable (Annexin V−/dye−), early apoptotic (Annexin V+/dye−), and late apoptotic or necrotic (Annexin V+/dye+) cell populations by assessing membrane integrity and PS exposure.

The NLRP3 inflammasome is a cytosolic innate immune signaling platform that integrates priming signals and danger-signal activation to promote caspase-1 activation, maturation of IL-1β and IL-18, and gasdermin D-mediated pyroptotic cell death. The core experimental logic is to determine whether inflammatory disease phenotypes are driven by increased NLRP3 expression, ASC-containing inflammasome assembly, caspase-1 cleavage, GSDMD cleavage, and extracellular release of IL-1β/IL-18 rather than by nonspecific cell injury alone. The pathway is strongly linked to inflammation-related disease phenotypes because monosodium urate crystals activate NALP3/NLRP3 inflammasome signaling in gout-like crystal inflammation, cholesterol crystals activate NLRP3 inflammasomes in atherogenesis models, and DSS-induced intestinal inflammation has been reported to involve NLRP3 inflammasome activity. However, experimental colitis studies also show context-dependent protective effects of NLRP3 inflammasome co

Breast cancer is a heterogeneous cancer, and it has been distinguished into four subtypes: luminal A, luminal B, HER2-positive and basal-like. Molecular mutations, epigenetic alterations, hormone exposure and immune microenvironment are related to the progression of breast cancer.

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.

Apoptosis, also called programmed cell death, is generally characterized by distinct morphological characteristics.

TUNEL staining detects DNA strand breaks by using terminal deoxynucleotidyl transferase to add labeled nucleotides to exposed 3′-OH DNA termini, generating either microscopic staining in fixed cells or tissue sections, or fluorescence/cytometric signal in cell suspensions. TUNEL positivity reflects DNA fragmentation but should not be interpreted alone as definitive apoptosis, because TUNEL can also label necrotic, autolytic, mechanically damaged, or DNA-repair-associated DNA breaks.

Lipopolysaccharide (LPS)-induced endotoxemia is a widely used in vivo model of acute systemic inflammation in which LPS, a Gram-negative bacterial endotoxin, activates innate immune signaling primarily through TLR4, leading to rapid and transient induction of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β in circulation and tissues. This cytokine surge is commonly used as a measurable readout of systemic inflammatory activation and immune dysregulation, and is typically assessed within hours after intraperitoneal LPS administration in mouse models of endotoxemia. The model captures key features of systemic inflammatory response syndrome, including cytokine release, immune cell activation, and downstream tissue responses, and has been used to evaluate anti-inflammatory interventions such as cytokine modulation, lipid mediators, and immune cell-targeting therapies.

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.

Cotton pellet granuloma is a classical in vivo chronic inflammation model used to evaluate the anti-inflammatory potential of test substances by measuring their ability to inhibit granuloma tissue formation around an implanted foreign body (cotton pellet) in rodents. The method is based on the biological response to a sterile implanted material, which induces proliferative phase inflammation characterized by fibroblast proliferation and collagen-rich granuloma formation, and the final readout reflects the extent of chronic inflammatory tissue growth surrounding the pellet. In multiple preclinical pharmacological evaluations, inhibition of cotton pellet-induced granuloma formation has been used as an indicator of anti-inflammatory activity in both synthetic and natural product screening contexts.

Human pluripotent stem cells are directed toward midbrain dopaminergic neurons by first inducing a neural floor-plate-like progenitor state, then patterning cells with ventralizing SHH signaling and midbrain/WNT-FGF cues, and finally maturing progenitors into neurons expressing dopaminergic markers such as TH, NURR1/NR4A2, PITX3, DAT/SLC6A3, VMAT2/SLC18A2, GIRK2/KCNJ6, FOXA2, LMX1A, and EN1. The main readouts are loss of pluripotency, acquisition of FOXA2+/LMX1A+ midbrain floor-plate progenitors, emergence of βIII-tubulin+/MAP2+ neurons, and production of TH+ dopaminergic neurons with molecular, dopamine-release, and electrophysiological features of midbrain dopaminergic identity.

Carrageenan-induced paw edema is an acute inflammation model in which intraplantar injection of carrageenan induces localized inflammatory swelling characterized by vascular permeability, leukocyte infiltration, and production of inflammatory mediators such as prostaglandins and cytokines, making it widely used to evaluate anti-inflammatory agents in vivo. The resulting paw volume or thickness increase is quantified over time as a direct readout of inflammatory intensity and drug efficacy, typically reflecting cyclooxygenase-mediated prostaglandin-driven edema formation and immune cell recruitment in peripheral tissue[20].

Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos

Inhalation toxicity studies expose rodents to a controlled aerosol, vapor, gas, or smoke atmosphere and assess respiratory and systemic toxicity using exposure-atmosphere characterization, clinical observations, body and organ weights, bronchoalveolar lavage fluid, histopathology, blood chemistry, hematology, and, when included, molecular endpoints such as transcriptomics, proteomics, lipidomics, or tissue burden analysis. The primary biological readouts are airway irritation, pulmonary inflammation, cytotoxicity, altered surfactant or lipid homeostasis, impaired particle clearance, and tissue remodeling, reflected by BALF cell differentials, BALF protein, LDH, phosphatase activities, cytokines, lung weight, microscopic respiratory-tract lesions, and retained lung burden.