Lytic Death Research Articles

ZBP1-driven cell death in severe influenza.

Influenza A virus (IAV) infections can cause life-threatening illness in humans. The severity of disease is directly linked to virus replication in the alveoli of the lower respiratory tract. In particular, the lytic death of infected alveolar epithelial cells (AECs) is a major driver of influenza severity. Recent studies have begun to define the molecular mechanisms by which IAV triggers lytic cell death. Z-form nucleic-acid-binding protein 1 (ZBP1) senses replicating IAV and drives programmed cell death (PCD) in infected cells, including apoptosis and necroptosis in AECs and pyroptosis in myeloid cells. Necroptosis and pyroptosis, both lytic forms of death, contribute to pathogenesis during severe infections. Pharmacological blockade of necroptosis shows strong therapeutic potential in mouse models of lethal influenza. We suggest that targeting ZBP1-initiated necroinflammatory cell lysis, either alone or in combination antiviral drugs, will provide clinical benefit in severe influenza.

Inhibition of ZFP281/ZNF281-RIPK1/RIPK3/MLKL signaling in hepatocytes by pterostilbene relieves hepatic lipometabolic disorder and inflammation in non-alcoholic steatohepatitis.

Non-alcoholic steatohepatitis (NASH) is the most common cause of chronic liver diseases with its pathophysiological mechanism poorly understood. In this work, serological, histological, molecular biological, biochemical, and immunological methods were applied to explore the pathological significance and action of zinc finger protein 281 (ZFP281 in mouse, ZNF281 in human) and targeted strategies. We reported that ZFP281/ZNF281 abundance in hepatocytes was positively correlated with the progression of NASH. Hepatocyte-specific knockdown of Zfp281 prevented mice from NASH diet-induced liver injury, steatosis, inflammation, and fibrosis. Consistently, the metabolic syndromes in NASH mice, characterized by obesity, hyperglycemia, insulin resistance, and hyperlipidemia, were also relieved by hepatocyte-specific Zfp281 deficiency. Mechanistically, incremental ZNF281 led to the upregulation of proinflammatory signaling, receptor-interacting protein kinase 1 (RIPK1)/RIPK3/mixed lineage kinase domain like pseudokinase (MLKL) axis in hepatocytes bearing free fatty acid stress. Activated MLKL translocated to the mitochondrial membrane, disrupting mitochondrial fatty acid β-oxidation and facilitating lipid accumulation in hepatocytes exposed to free fatty acid stimulation; also, MLKL in activated form orientated to the plasma membrane, triggering the lytic death mode in hepatocytes and launching hepatocellular proinflammatory responses. Moreover, we screened a ZFP281 inhibitor, pterostilbene, and demonstrated that pterostilbene, by inhibiting ZFP281 elevation in NASH livers, reduced hepatocyte injury, steatosis, inflammatory responses and fibrogenesis. In conclusion, this work proposes that induction of ZFP281/ZNF281-RIPK1/RIPK3/MLKL signaling disrupts fatty acid metabolism, promoting lipid accumulation, and triggers proinflammatory cell death, accelerating hepatic necroinflammation. Our work identifies ZFP281/ZNF281 as a promising target as well as pterostilbene as a potential strategy for NASH managing.

NETosis Impact on Tumor Biology, Radiation, and Systemic Therapy Resistance.

Neutrophil extracellular trap (NET)osis via lytic neutrophil death or neutrophil activation is associated with standard cancer therapies, notably including radiotherapy; is immunosuppressive; and may enhance metastasis and treatment resistance. This emerging area of research should be prioritized in drug development and standard of care treatment paradigms including radiation therapy, chemotherapy, and immunotherapy. See related article by Teijeira et al., p. 4131.

Gasdermin E dictates inflammatory responses by controlling the mode of neutrophil death

Both lytic and apoptotic cell death remove senescent and damaged cells in living organisms. However, they elicit contrasting pro- and anti-inflammatory responses, respectively. The precise cellular mechanism that governs the choice between these two modes of death remains incompletely understood. Here we identify Gasdermin E (GSDME) as a master switch for neutrophil lytic pyroptotic death. The tightly regulated GSDME cleavage and activation in aging neutrophils are mediated by proteinase-3 and caspase-3, leading to pyroptosis. GSDME deficiency does not alter neutrophil overall survival rate; instead, it specifically precludes pyroptosis and skews neutrophil death towards apoptosis, thereby attenuating inflammatory responses due to augmented efferocytosis of apoptotic neutrophils by macrophages. In a clinically relevant acid-aspiration-induced lung injury model, neutrophil-specific deletion of GSDME reduces pulmonary inflammation, facilitates inflammation resolution, and alleviates lung injury. Thus, by controlling the mode of neutrophil death, GSDME dictates host inflammatory outcomes, providing a potential therapeutic target for infectious and inflammatory diseases.

Gasdermin D activation in oligodendrocytes and microglia drives inflammatory demyelination in progressive multiple sclerosis

Neuroinflammation coupled with demyelination and neuro-axonal damage in the central nervous system (CNS) contribute to disease advancement in progressive multiple sclerosis (P-MS). Inflammasome activation accompanied by proteolytic cleavage of gasdermin D (GSDMD) results in cellular hyperactivation and lytic death. Using multiple experimental platforms, we investigated the actions of GSDMD within the CNS and its contributions to P-MS. Brain tissues from persons with P-MS showed significantly increased expression of GSDMD, NINJ1, IL-1β, and −18 within chronic active demyelinating lesions compared to MS normal appearing white matter and nonMS (control) white matter. Conditioned media (CM) from stimulated GSDMD+/+ human macrophages caused significantly greater cytotoxicity of oligodendroglial and neuronal cells, compared to CM from GSDMD-/- macrophages. Oligodendrocytes and CNS macrophages displayed increased Gsdmd immunoreactivity in the central corpus callosum (CCC) of cuprizone (CPZ)-exposed Gsdmd+/+ mice, associated with greater demyelination and reduced oligodendrocyte precursor cell proliferation, compared to CPZ-exposed Gsdmd-/- animals. CPZ-exposed Gsdmd+/+ mice exhibited significantly increased G-ratios and reduced axonal densities in the CCC compared to CPZ-exposed Gsdmd-/- mice. Proteomic analyses revealed increased brain complement C1q proteins and hexokinases in CPZ-exposed Gsdmd-/- animals. [18F]FDG PET imaging showed increased glucose metabolism in the hippocampus and whole brain with intact neurobehavioral performance in Gsdmd-/- animals after CPZ exposure. GSDMD activation in CNS macrophages and oligodendrocytes contributes to inflammatory demyelination and neuroaxonal injury, offering mechanistic and potential therapeutic insights into P-MS pathogenesis.

Control of Cell Death in Health and Disease.

Apoptosis, necroptosis, and pyroptosis are genetically programmed cell death mechanisms that eliminate obsolete, damaged, infected, and self-reactive cells. Apoptosis fragments cells in a manner that limits immune cell activation, whereas the lytic death programs of necroptosis and pyroptosis release proinflammatory intracellular contents. Apoptosis fine-tunes tissue architecture during mammalian development, promotes tissue homeostasis, and is crucial for averting cancer and autoimmunity. All three cell death mechanisms are deployed to thwart the spread of pathogens. Disabling regulators of cell death signaling in mice has revealed how excessive cell death can fuel acute or chronic inflammation. Here we review strategies for modulating cell death in the context of disease. For example, BCL-2 inhibitor venetoclax, an inducer of apoptosis, is approved for the treatment of certain hematologic malignancies. By contrast, inhibition of RIPK1, NLRP3, GSDMD, or NINJ1 to limit proinflammatory cell death and/or the release of large proinflammatory molecules from dying cells may benefit patients with inflammatory diseases.

Intracellular replication of Pseudomonas aeruginosa in epithelial cells requires suppression of the caspase-4 inflammasome.

Pathogenesis of Pseudomonas aeruginosa infections can include bacterial survival inside epithelial cells. Previously, we showed that this involves multiple roles played by the type three secretion system (T3SS), and specifically the effector ExoS. This includes ExoS-dependent inhibition of a lytic host cell response that subsequently enables intracellular replication. Here, we studied the underlying cell death response to intracellular P. aeruginosa, comparing wild-type to T3SS mutants varying in capacity to induce cell death and that localize to different intracellular compartments. Results showed that corneal epithelial cell death induced by intracellular P. aeruginosa lacking the T3SS, which remains in vacuoles, correlated with the activation of nuclear factor-κB as measured by p65 relocalization and tumor necrosis factor alpha transcription and secretion. Deletion of caspase-4 through CRISPR-Cas9 mutagenesis delayed cell death caused by these intracellular T3SS mutants. Caspase-4 deletion also countered more rapid cell death caused by T3SS effector-null mutants still expressing the T3SS apparatus that traffic to the host cell cytoplasm, and in doing so rescued intracellular replication normally dependent on ExoS. While HeLa cells lacked a lytic death response to T3SS mutants, it was found to be enabled by interferon gamma treatment. Together, these results show that epithelial cells can activate the noncanonical inflammasome pathway to limit proliferation of intracellular P. aeruginosa, not fully dependent on bacterially driven vacuole escape. Since ExoS inhibits the lytic response, the data implicate targeting of caspase-4, an intracellular pattern recognition receptor, as another contributor to the role of ExoS in the intracellular lifestyle of P. aeruginosa. IMPORTANCE Pseudomonas aeruginosa can exhibit an intracellular lifestyle within epithelial cells in vivo and in vitro. The type three secretion system (T3SS) effector ExoS contributes via multiple mechanisms, including extending the life of invaded host cells. Here, we aimed to understand the underlying cell death inhibited by ExoS when P. aeruginosa is intracellular. Results showed that intracellular P. aeruginosa lacking T3SS effectors could elicit rapid cell lysis via the noncanonical inflammasome pathway. Caspase-4 contributed to cell lysis even when the intracellular bacteria lacked the entire T33S and were consequently unable to escape vacuoles, representing a naturally occurring subpopulation during wild-type infection. Together, the data show the caspase-4 inflammasome as an epithelial cell defense against intracellular P. aeruginosa, and implicate its targeting as another mechanism by which ExoS preserves the host cell replicative niche.

Altered growth and death in dilution-based viral predation assays.

Viral lysis of phytoplankton is one of the most common forms of death on Earth. Building on an assay used extensively to assess rates of phytoplankton loss to predation by grazers, lysis rates are increasingly quantified through dilution-based techniques. In this approach, dilution of viruses and hosts are expected to reduce infection rates and thus increase host net growth rates (i.e., accumulation rates). The difference between diluted and undiluted host growth rates is interpreted as a measurable proxy for the rate of viral lytic death. These assays are usually conducted in volumes ≥ 1 L. To increase throughput, we implemented a miniaturized, high-throughput, high-replication, flow cytometric microplate dilution assay to measure viral lysis in environmental samples sourced from a suburban pond and the North Atlantic Ocean. The most notable outcome we observed was a decline in phytoplankton densities that was exacerbated by dilution, instead of the increased growth rates expected from lowered virus-phytoplankton encounters. We sought to explain this counterintuitive outcome using theoretical, environmental, and experimental analyses. Our study shows that, while die-offs could be partly explained by a 'plate effect' due to small incubation volumes and cells adhering to walls, the declines in phytoplankton densities are not volume-dependent. Rather, they are driven by many density- and physiology-dependent effects of dilution on predation pressure, nutrient limitation, and growth, all of which violate the original assumptions of dilution assays. As these effects are volume-independent, these processes likely occur in all dilution assays that our analyses show to be remarkably sensitive to dilution-altered phytoplankton growth and insensitive to actual predation pressure. Incorporating altered growth as well as predation, we present a logical framework that categorizes locations by the relative dominance of these mechanisms, with general applicability to dilution-based assays.

Malignant human thyroid neoplasms associated with blood parasitic (haemosporidian) infection

A retrospective investigation of archival cytology specimens obtained and verified by a fine-needle aspiration biopsy from patients with follicular, papillary, and medullary human thyroid cancers revealed haemosporidian (blood parasitic) infection in thyrocytes (schizogony) and erythrocytes. The exoerythrocytic stage of infection is represented by finding microschizonts. Cytologic material was stained with RomanowskyGiemsa dye in medical laboratories. Original specimens were stained (re-stained) with Schiff reagent according to the Feulgen method to clarify location of thyrocyte DNA and hemosporidian pathogens, wherein fuchsine was incorporated into DNA molecules after they were hydrolyzed by hydrochloric acid to stain specimens into red-violet color. An intentionally unstained hemosporidian protoplasm during blood parasitic infection was observed as a light band around erythrocyte nuclei. In follicular thyroid cancer, thyrocyte Feulgen staining revealed nuclear DNA and parasitic DNA (haemosporidium nuclei) as punctate inclusions and rings diffusely distributed in the thyrocyte cytoplasm. The thyrocyte cytoplasm and nuclei were vacuolated, with thyrocyte nuclei being deformed, flattened, and displaced to the cell periphery. The erythrocytes contained haemosporidian nuclei (DNA). In papillary thyroid cancer, we were able to localize the nuclear DNA of thyrocytes and the parasitic DNA as punctate inclusions diffusely distributed in the thyrocyte cytoplasm. Two or more polymorphic nuclei may be positioned eccentrically in the hyperplastic cytoplasm. Haemosporidian microschizonts were found circumnuclearly in thyrocytes as well as an exoerythrocytic stage in the blood. In medullary thyroid cancer, the hyperplastic cytoplasm of thyrocytes contained eccentrically located nuclei (DNA) of thyrocytes and small haemosporidian nuclei (DNA), which may occupy the whole thyrocyte. There were thyrocytes with vacuolated cytoplasm and prominent nuclear polymorphism. The size of hyperplastic nuclei was several times larger than that of normal thyrocyte nuclei. The color of stained thyrocyte cytoplasmic and nuclear vacuoles was less red-violet compared with that of surrounding tissues, which potentially indicates the presence of parasitic DNA inside them. The intra-erythrocyte nuclear haemosporidian material of varying sizes in papillary and medullary cancers may evidence about various species and/or pathogen generation. Intracellular parasitism of haemosporidian infection in thyrocytes (schizogony) associated with three thyroid cancer types leads to marked thyrocyte cytoplasmic hyperplasia, cytoplasmic vacuolization, and nuclear vacuolization. Multinucleated thyrocytes with incomplete cytokinesis emerge. Nuclear deformation occurs, which leads to decreased nucleus size, flattening and displacement to the cell periphery, with high risk of DNA mutations and deletions in affected cells, reaching a neoplastic level.

Systematic pan-cancer analysis identifies gasdermin B as an immunological and prognostic biomarker for kidney renal clear cell carcinoma.

Gasdermin (GSDM)-mediated cell lytic death plays an essential role in immunity and tumorigenesis. Despite the association of gasdermin B (GSDMB) with the tumorigenesis of various cancers, whether GSDMB functions as a prognostic biomarker in renal cell carcinoma remains poorly understood. Here, we explored the potential immunological functions and the prognostic value of GSDMB across multiple tumors with The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, including analyzing the relationship between GSDMB expression and prognosis, tumor-immune system interactions, immunomodulators, and immune cell infiltration of different tumors. Importantly, elevated expression of GSDMB is an essential factor for the poor prognosis of kidney renal clear cell carcinoma (KIRC) patients, suggesting that it might be helpful to predict a survival benefit from a clinical therapy regimen. Furthermore, GSDMB expression promoted the level of CD4+ T-cell infiltration of the tumors but is significantly negatively associated with immature dendritic cells (iDCs) in KIRC. Additionally, we identified TNFRSF25 and TNFSF14 as immunostimulators highly correlated with GSDMB expression. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses showed that GSDMB and its interacting proteins might affect tumor growth through the serine metabolism pathway. Our current results demonstrate a promising therapeutic strategy targeting GSDMB and provide new insights into GSDMB as an immunological and prognostic biomarker for KIRC.

CASP4 can be a diagnostic biomarker and correlated with immune infiltrates in gliomas.

Gliomas are the most common and invasive malignant tumors that originate in the central nervous system. Currently, the primary treatment modality for gliomas is maximum surgical resection, supplemented by radiotherapy and chemotherapy. However, the long-term survival rate has not signifificantly increased. Pyroptosis is a new form of programmed lytic death that has been recently discovered. Caspase 4 (CASP4) plays a key role in pyroptosis. Many studies have shown that pyroptosis is not only related to inflflammation but is also closely related to the occurrence and development of most tumors. This study aimed to prove that CASP4 has a key role in the mechanism of gliomas. We used expression data from The Cancer Genome Atlas and the Chinese Glioma Genome Atlas to explore the relationship between CASP4 expression and glioma prognosis. The differential expression of CASP4 in gliomas and normal tissues was fifirst tested, and then the connection between CASP4 and tumor prognosis was explored. The relationship between CASP4 expression and immune cell infifiltration was also investigated. Finally, the possible pathways were analyzed using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis. CASP4 was highly expressed and associated with a signifificantly lower survival rate in patients with glioma. It could also inflfluence immune cell infifiltration by releasing cytokines. CASP4 can be a diagnostic biomarker and is a promising therapeutic target for gliomas.

Disulfiram attenuates hypoxia-induced pulmonary hypertension by inhibiting GSDMD cleavage and pyroptosis in HPASMCs

BackgroundPulmonary hypertension (PH) is characterized by progressive pulmonary arterial remodelling, associated with different severities of inflammation and altered immune processes. Disulfiram eliminates the formation of N-gasdermin D (GSDMD) plasma membrane pores to prevent pyroptosis. Pyroptosis is a form of lytic cell death characterized by inflammasome activation and proinflammatory cytokine release that acts in the development of PH. We sought to investigate whether disulfiram could alleviate hypoxia-induced PH by inhibiting pyroptosis.MethodsTo investigate whether disulfiram alleviates the progression of pulmonary hypertension, rodents were exposed to chronic hypoxia (10% oxygen, 4 weeks) to induce PH. The severity of PH was assessed by measuring right ventricular systolic pressure, mean pulmonary artery pressure, and the degree of right ventricular hypertrophy. Western blotting was used to measure proteins associated with the pyroptosis pathway, and ELISA was performed to measure the secretion of IL-18 and IL-1β, both of which are the primary methods for assessing pyroptosis.ResultsIL-18 and IL-1β concentrations were higher in patients with PH than in normal controls. Disulfiram suppressed the progression of PH in mice and rats through the alleviation of pulmonary arterial remodelling. Pyroptosis-related proteins and the inflammasome were activated in rodent models of PH. Disulfiram inhibited the processing of GSDMD into N-GSDMD and attenuated the secretion of IL-1β and IL18. In vivo experiments showed that disulfiram also inhibited lytic death in HPASMCs.ConclusionsDisulfiram treatment reduces PH progression through suppressing vascular remodelling by inhibiting GSDMD cleavage and pyroptosis. It might become a novel therapeutic option for the treatment of PH.

Caspase-1: A Promising Target for Preserving Blood-Brain Barrier Integrity in Acute Stroke.

The blood–brain barrier (BBB) acts as a physical and biochemical barrier that plays a fundamental role in regulating the blood-to-brain influx of endogenous and exogenous components and maintaining the homeostatic microenvironment of the central nervous system (CNS). Acute stroke leads to BBB disruption, blood substances extravasation into the brain parenchyma, and the consequence of brain edema formation with neurological impairment afterward. Caspase-1, one of the evolutionary conserved families of cysteine proteases, which is upregulated in acute stroke, mainly mediates pyroptosis and compromises BBB integrity via lytic cellular death and inflammatory cytokines release. Nowadays, targeting caspase-1 has been proven to be effective in decreasing the occurrence of hemorrhagic transformation (HT) and in attenuating brain edema and secondary damages during acute stroke. However, the underlying interactions among caspase-1, BBB, and stroke still remain ill-defined. Hence, in this review, we are concerned about the roles of caspase-1 activation and its associated mechanisms in stroke-induced BBB damage, aiming at providing insights into the significance of caspase-1 inhibition on stroke treatment in the near future.

Neutrophil and remnant clearance in immunity and inflammation

Neutrophil-centred inflammation and flawed clearance of neutrophils cause and exuberate multiple pathological conditions. These most abundant leukocytes exhibit very high daily turnover in steady-state and stress conditions. Various armours including oxidative burst, NETs and proteases function against pathogens, but also dispose neutrophils to spawn pro-inflammatory responses. Neutrophils undergo death through different pathways upon ageing, infection, executing the intruder's elimination. These include non-lytic apoptosis and other lytic deaths including NETosis, necroptosis and pyroptosis with distinct disintegration of the cellular membrane. This causes release and presence of different intracellular cytotoxic, and tissue-damaging content as cell remnants in the extracellular environment. The apoptotic cells and apoptotic bodies get cleared with non-inflammatory outcomes, while lytic deaths associated remnants including histones and cell-free DNA cause pro-inflammatory responses. Indeed, the enhanced frequencies of neutrophil-associated proteases, cell-free DNA and autoantibodies in diverse pathologies including sepsis, asthma, lupus and rheumatoid arthritis, imply disturbed neutrophil resolution programmes in inflammatory and autoimmune diseases. Thus, the clearance mechanisms of neutrophils and associated remnants are vital for therapeutics. Though studies focused on clearance mechanisms of senescent or apoptotic neutrophils so far generated a good understanding of the same, clearance of neutrophils undergoing distinct lytic deaths, including NETs, are being the subjects of intense investigations. Here, in this review, we are providing the current updates in the clearance mechanisms of apoptotic neutrophils and focusing on not so well-defined recognition, uptake and degradation of neutrophils undergoing lytic death and associated remnants that may provide new therapeutic approaches in inflammation and autoimmunity.

Regulated lytic cell death in breast cancer.

Breast cancer (BC) is a very common cancer among women and one of the primary causes of death in women worldwide. Because BC has different molecular subtypes, the challenges associated with targeted therapy have increased significantly, and the identification of new therapeutic targets has become increasingly urgent. Blocking apoptosis and inhibiting cell death are important characteristics of malignant tumours, including BC. Under adverse conditions, including exposure to antitumour therapy, inhibition of cell death programmes can promote cancerous transformation and the survival of cancer cells. Therefore, inducing cell death in cancer cells is fundamentally important and provides new opportunities for potential therapeutic interventions. Lytic forms of cell death, primarily pyroptosis, necroptosis and ferroptosis, are different from apoptosis owing to their characteristic lysis, that is, the production of cellular components, to guide beneficial immune responses, and the application of lytic cell death (LCD) in the field of tumour therapy has attracted considerable interest from researchers. The latest clinical research results confirm that lytic death signalling cascades involve the BC cell immune response and resistance to therapies used in clinical practice. In this review, we discuss the current knowledge regarding the various forms of LCD, placing a special emphasis on signalling pathways and their implications in BC, which may facilitate the development of novel and optimal strategies for the clinical treatment of BC.

554P Phase I clinical trial of OBP-301, a novel telomerase-specific oncolytic virus, in combination with radiotherapy in esophageal cancer patients

OBP-301 is a novel condition-restricted, replication-competent adenovirus derived from human adenovirus type 5 that incorporates a human telomerase reverse transcriptase (hTERT) promoter. This construct causes tumor-specific viral replication and lytic death of a variety of cancer cells, and safety of OBP-301 monotherapy has been confirmed in patients with solid tumor in phase I clinical trial. We conducted phase I clinical trial to evaluate safety, tolerability and efficacy of OBP-301 in combination with radiotherapy.

Quantitative Confocal Microscopy for Grouping of Dose-Response Data: Deciphering Calcium Sequestration and Subsequent Cell Death in the Presence of Excess Norepinephrine.

Fluorescent calcium (Ca2+) imaging is one of the preferred methods to record cellular activity during in vitro preclinical studies, high-content drug screening, and toxicity analysis. Visualization and analysis for dose-response data obtained using high-resolution imaging remain challenging, due to the inherent heterogeneity present in the Ca2+ spiking. To address this challenge, we propose measurement of cytosolic Ca2+ ions using spinning-disk confocal microscopy and machine learning-based analytics that is scalable. First, we implemented uniform manifold approximation and projection (UMAP) for visualizing the multivariate time-series dataset in the two-dimensional (2D) plane using Python. The dataset was obtained through live imaging experiments with norepinephrine-induced Ca2+ oscillation in HeLa cells for a large range of doses. Second, we demonstrate that the proposed framework can be used to depict the grouping of the spiking pattern for lower and higher drug doses. To the best of our knowledge, this is the first attempt at UMAP visualization of the time-series dose response and identification of the Ca2+ signature during lytic death. Such quantitative microscopy can be used as a component of a high-throughput data analysis workflow for toxicity analysis.

An in-host HIV-1 infection model incorporating quiescent and activated CD4[formula omitted] T cells as well as CTL response

A mathematical model is proposed to capture the implication of quiescent and activated CD4+ T cells as well as the cytotoxic T lymphocyte (CTL) response on HIV-1 infection in an early stage. It underlies the different mechanisms behind the productive and latent infection, whereby virion-cell contact, cell-cell contact, immune response, slow-kinetic viral reverse transcription in quiescent cells, lytic death, pyroptosis, and virus survival play their significant role within. The existence, uniqueness, and global stability of both the virus-free and endemic equilibrium with respect to the magnitudes of the basic reproduction ratio are studied. Due to technical difficulties in revealing the close form of the endemic equilibrium, determining the whole picture of forward bifurcation around the virus-free states is accomplished with the aid of bifurcation theory. The sufficient condition for the forward bifurcation is satisfied by the choices of the parameter values, and simulations are presented to illustrate the analytical findings. In an effort to study which parameters can be attacked through the applications of RTIs, PIs, and vaccination toward foremost reduction of the basic reproduction ratio, a local sensitivity analysis is presented. Finally, a model version combining productive and latent infection, also treating disparate time scales from CD4+ T cells and CTLs as well as virions is studied. As long as any solution trajectory is initiated around the stable part of the critical manifold, it approaches and stays around the manifold and eventually lands in the manifold when the lifespans of CTLs and virions are comparably small. If the corresponding basic reproduction ratio is sufficiently large, then not only does the endemic equilibrium locate in the unstable part of the critical manifold, but all the solution trajectories (from the stable part) converge to the equilibrium due to global stability, indicating the existence of canards.

Effects of Wild Yam Root (Dioscorea villosa) Extract on the Gene Expression Profile of Triple-negative Breast Cancer Cells

Wild yam extract [Dioscorea villosa, (WYE)] is consistently lethal at low IC50s across diverse cancer-lines in vitro. Unlike traditional anti-cancer botanicals, WYE contains detergent saponins which reduce oil-water interfacial tensions causing disintegration of lipid membranes and causing cell lysis, creating an interfering variable. Here, we evaluate WYE at sub-lethal concentrations in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Quantification of saponins, membrane potential, lytic death and sub-lethal WYE changes in whole transcriptomic (WT) mRNA, miRNAs and biological parameters were evaluated. WYE caused 346 differentially expressed genes (DEGs) out of 48,226 transcripts tested; where up-regulated DEGS reflect immune stimulation, TNF signaling, COX2, cytokine release and cholesterol/steroid biosynthesis. Down-regulated DEGs reflect losses in cell division cycle (CDC), cyclins (CCN), cyclin-dependent kinases (CDKs), centromere proteins (CENP), kinesin family members (KIFs) and polo-like kinases (PLKs), which were in alignment with biological studies. Sub-lethal concentrations of WYE appear to evoke pro-inflammatory, steroid biosynthetic and cytostatic effects in TNBC cells.

Gasdermin Family: a Promising Therapeutic Target for Stroke.

Stroke is one of the leading causes of death worldwide and therapies are limited. According to the mechanisms underlying stroke, direct cell demise, destruction of organelles, blood-brain barrier disruption, neuroinflammation are potential therapeutic targets. Gasdermin (GSDM) family is a series of recently discovered proteins, which acts as the executor of pyroptosis and protagonist of membrane pore formation. It can be cleaved by inflammatory caspases that are activated by multi-protein complexes, named as inflammasomes, and divided into two domains. The N-terminal domain interacts with lipid localized in the plasma membrane as well as organelle membrane and perforates them. After the formation of pores, the dysfunctional structures suffer lytic death and their contents are released. In this review, we discuss the biological characteristic of GSDM family and their possible roles in stroke-induced brain injury, and based on the review, we hypothesize the feasibility of using GSDMs as a potential target for stroke treatment.