Pathogen hijacks programmed cell death signaling by arginine ADPR-deacylization of caspases.

Caspases are evolutionarily conserved cysteine proteases that are essential for regulating cell death and are involved in multiple development and disease processes, including immunity. Here, we show that the bacterial type III secretion system (T3SS) effector CopC (Chromobacterium outer protein C) from the environmental pathogen Chromobacterium violaceum attacks caspase-3/-7/-8/-9 by ADPR-deacylization to dysregulate programmed cell death, including apoptosis, necroptosis, and pyroptosis. This modification involves ADP-ribosylation- and deamination-mediated cyclization on Arg207 of caspase-3 by a mechanism that requires the eukaryote-specific protein calmodulin (CaM), leading to inhibition of caspase activity. The manipulation of cell death signaling by CopC is essential for the virulence of C. violaceum in a mouse infection model. CopC represents a family of enzymes existing in taxonomically diverse bacteria associated with a wide spectrum of eukaryotes ranging from humans to plants. The unique activity of CopC establishes a mechanism by which bacteria counteract host defenses through a previously unrecognized post-translational modification.

African swine fever virus infection regulates pyroptosis by cleaving gasdermin A via active caspase-3 and caspase-4.

African swine fever, caused by the African swine fever virus (ASFV), is a viral hemorrhagic disease that affects domestic pigs and wild boars. ASFV infection causes extensive tissue damage, and the associated mechanism is poorly understood. Pyroptosis is characterized by the activation of inflammatory caspases and pore formation in the cellular plasma membrane, resulting in the release of inflammatory cytokines and cell damage. How ASFV infection regulates pyroptosis remains unclear. Here, using siRNA assay and overexpression methods, we report that ASFV infection regulated pyroptosis by cleaving the pyroptosis execution protein gasdermin A (GSDMA). ASFV infection activated caspase-3 and caspase-4, which specifically cleaved GSDMA at D75-P76 and D241-V242 to produce GSDMA into five fragments, including GSDMA-N1-75, GSDMA-N1-241, and GSDMA-N76-241 fragments at the N-terminal end of GSDMA. Only GSDMA-N1-241, which was produced in the late stage of ASFV infection, triggered pyroptosis and inhibited ASFV replication. The fragments, GSDMA-N1-75 and GSDMA-N76-241, lose the ability to induce pyroptosis. Overall ASFV infection differentially regulates pyroptosis by GSDMA in the indicated phase, which may be conducive to its own replication. Our findings reveal a novel molecular mechanism for the regulation of pyroptosis.

Activation of innate immune receptor TLR9 by mitochondrial DNA plays essential roles in the chemical long-term depression of hippocampal neurons.

Synaptic plasticity is believed to be the cellular basis for experience-dependent learning and memory. Although long-term depression (LTD), a form of synaptic plasticity, is caused by the activity-dependent reduction of cell surface α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors (AMPA receptors) at postsynaptic sites, its regulation by neuronal activity is not completely understood. In this study, we showed that the inhibition of toll-like receptor-9 (TLR9), an innate immune receptor, suppresses N-methyl-d-aspartate (NMDA)-induced reduction of cell surface AMPA receptors in cultured hippocampal neurons. We found that inhibition of TLR9 also blocked NMDA-induced activation of caspase-3, which plays an essential role in the induction of LTD. siRNA-based knockdown of TLR9 also suppressed the NMDA-induced reduction of cell surface AMPA receptors, although the scrambled RNA had no effect on the NMDA-induced trafficking of AMPA receptors. Overexpression of the siRNA-resistant form of TLR9 rescued the AMPA receptor trafficking abolished by siRNA. Furthermore, NMDA stimulation induced rapid mitochondrial morphological changes, mitophagy, and the binding of mitochondrial DNA (mtDNA) to TLR9. Treatment with dideoxycytidine and mitochondrial division inhibitor-1, which block mtDNA replication and mitophagy, respectively, inhibited NMDA-dependent AMPA receptor internalization. These results suggest that mitophagy induced by NMDA receptor activation releases mtDNA and activates TLR9, which plays an essential role in the trafficking of AMPA receptors during the induction of LTD.

Cleavage of protein kinase c δ by caspase-3 mediates proinflammatory cytokine-induced apoptosis in pancreatic islets.

In type 1 diabetes (T1D), autoreactive immune cells infiltrate the pancreas and secrete proinflammatory cytokines that initiate cell death in insulin producing islet ß-cells. Protein kinase C δ (PKCδ) plays a role in mediating cytokine-induced ß-cell death; however, the exact mechanisms are not well understood. To address this, we used an inducible ß-cell specific PKCδ KO mouse as well as a small peptide inhibitor of PKCδ. We identified a role for PKCδ in mediating cytokine-induced ß-cell death and have shown that inhibiting PKCδ protects pancreatic ß-cells from cytokine-induced apoptosis in both mouse and human islets. We determined that cytokines induced nuclear translocation and activity of PKCδ and that caspase-3 cleavage of PKCδ may be required for cytokine-mediated islet apoptosis. Further, cytokine activated PKCδ increases activity both of proapoptotic Bax with acute treatment and C-Jun N-terminal kinase with prolonged treatment. Overall, our results suggest that PKCδ mediates cytokine-induced apoptosis via nuclear translocation, cleavage by caspase-3, and upregulation of proapoptotic signaling in pancreatic ß-cells. Combined with the protective effects of PKCδ inhibition with δV1-1, the results of this study will aid in the development of novel therapies to prevent or delay ß-cell death and preserve ß-cell function in T1D.

Classical apoptotic stimulus, staurosporine, induces lytic inflammatory cell death, PANoptosis.

Innate immunity is the body's first line of defense against disease, and regulated cell death is a central component of this response that balances pathogen clearance and inflammation. Cell death pathways are generally categorized as non-lytic and lytic. While non-lytic apoptosis has been extensively studied in health and disease, lytic cell death pathways are increasingly implicated in infectious and inflammatory diseases and cancers. Staurosporine (STS) is a well-known inducer of non-lytic apoptosis. However, in this study, we observed that STS also induces lytic cell death at later timepoints. Using biochemical assessments with genetic knockouts, pharmacological inhibitors, and gene silencing, we identified that STS triggered PANoptosis via the caspase-8/RIPK3 axis, which was mediated by RIPK1. PANoptosis is a unique, lytic, innate immune cell death pathway initiated by innate immune sensors and driven by caspases and RIPKs through PANoptosome complexes. Deletion of caspase-8 and RIPK3, core components of the PANoptosome complex, protected against STS-induced lytic cell death. Overall, our study identifies STS as a time-dependent inducer of lytic inflammatory cell death, PANoptosis. These findings emphasize the importance of understanding trigger- and time-specific activation of distinct cell death pathways to advance our understanding of the molecular mechanisms of innate immunity and cell death for clinical translation.

PA-824 inhibits porcine epidemic diarrhea virus infection in vivo and in vitro by inhibiting p53 activation.

Porcine epidemic diarrhea virus (PEDV) is a type A coronavirus that causes severe watery diarrhea in piglets, resulting in severe economic losses worldwide. Therefore, new approaches to control PEDV infection are essential for a robust and sustainable pig industry. We screened 314 small-molecule drug libraries provided by Selleck and found that four drugs had obviously inhibitory effects on PEDV in Vero cells. PA-824, which had the highest SI index and the most reliable clinical safety, was selected for in vivo experiments. Animal attack tests showed that PA-824 effectively alleviated the clinical signs, intestinal pathological changes, and inflammatory responses in lactating piglets after PEDV infection. To further investigate the antiviral mechanism of PA-824, we measured the inhibitory effect of PA-824 on PEDV proliferation in a dose-dependent manner. By exploring the effect of PA-824 on the PEDV life cycle, we found that PA-824 acted directly on viral particles and hindered the adsorption, internalization, and replication phases of the virus, followed by molecular docking analysis to predict the interaction between PA-824 and PEDV non-structural proteins. Finally, we found that PA-824 could inhibit the apoptotic signaling pathway by suppressing PEDV-induced p53 activation. These results suggest that PA-824 could be protective against PEDV infection in piglets and could be developed as a drug or a feed additive to prevent and control PEDV diseases.IMPORTANCEPEDV is a highly contagious enteric coronavirus that widely spread worldwide, causing serious economic losses. There is no drug or vaccine to effectively control PEDV. In this study, we found that PA-824, a compound of mycobacteria causing pulmonary diseases, inhibited PEDV proliferation in both in vitro and in vivo. We also found that PA-824 directly acted on viral particles and hindered the adsorption, internalization, and replication stages of the virus. In addition, we found that PA-824 could inhibit the apoptotic signaling pathway by inhibiting PEDV-induced p53 activation. In conclusion, it is expected to be developed as a drug or a feed additive to prevent and control PEDV diseases.

TMEM16A regulates satellite cell mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.

It has been documented that caspase 3 activity is necessary for skeletal muscle regeneration, but how its activity is regulated is largely unknown. Our previous report shows that intracellular TMEM16A, a calcium activated chloride channel, significantly regulates caspase 3 activity in myoblasts during skeletal muscle development. By using a mouse line with satellite cell (SC)-specific deletion of TMEM16A, we examined the role of TMEM16A in regulating caspase 3 activity in SC (or SC-derived myoblast) as well as skeletal muscle regeneration. The mutant animals displayed apparently impaired regeneration capacity in adult muscle along with enhanced ER stress and elevated caspase 3 activity in Tmem16a-/- SC derived myoblasts. Blockade of either excessive ER stress or caspase 3 activity by small molecules significantly restored the inhibited myogenic differentiation of Tmem16a-/- SCs, indicating that excessive caspase 3 activity resulted from TMEM16A deletion contributes to the impaired muscle regeneration and the upstream regulator of caspase 3 was ER stress. Our results revealed an essential role of TMEM16A in satellite cell mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.

Design, in silico evaluation, and in vitro verification of new bivalent Smac mimetics with pro-apoptotic activity.

Bivalent Smac mimetics have been shown to possess binding affinity and pro-apoptotic activity similar to or more potent than that of native Smac, a protein dimer able to neutralize the anti-apoptotic activity of an inhibitor of caspase enzymes, XIAP, which endows cancer cells with resistance to anticancer drugs. We design five new bivalent Smac mimetics, which are formed by various linkers tethering two diazabicyclic cores being the IAP binding motifs. We built in silico models of the five mimetics by the TwistDock workflow and evaluated their conformational tendency, which suggests that compound 3, whose linker is n-hexylene, possess the highest binding potency among the five. After synthesis of these compounds, their ability in tumour cell growth inhibition and apoptosis induction displayed in experiments with SK-OV-3 and MDA-MB-231 cancer cell lines confirms our prediction. Among the five mimetics, compound 3 displays promising pro-apoptotic activity and deserves further optimization.

In-Depth Characterization of Apoptosis N-Terminome Reveals a Link Between Caspase-3 Cleavage and Posttranslational N-Terminal Acetylation.

The N termini of proteins contain information about their biochemical properties and functions. These N termini can be processed by proteases and can undergo other co- or posttranslational modifications. We have developed LATE (LysN Amino Terminal Enrichment), a method that uses selective chemical derivatization of α-amines to isolate the N-terminal peptides, in order to improve N-terminome identification in conjunction with other enrichment strategies. We applied LATE alongside another N-terminomic method to study caspase-3-mediated proteolysis both in vitro and during apoptosis in cells. This has enabled us to identify many unreported caspase-3 cleavages, some of which cannot be identified by other methods. Moreover, we have found direct evidence that neo-N-termini generated by caspase-3 cleavage can be further modified by Nt-acetylation. Some of these neo-Nt-acetylation events occur in the early phase of the apoptotic process and may have a role in translation inhibition. This has provided a comprehensive overview of the caspase-3 degradome and has uncovered previously unrecognized cross talk between posttranslational Nt-acetylation and caspase proteolytic pathways.

Effect of Selective Lesions of Nucleus Accumbens µ-Opioid Receptor-Expressing Cells on Heroin Self-Administration in Male and Female Rats: A Study with Novel Oprm1-Cre Knock-in Rats.

The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-based Oprm1-Cre knock-in transgenic rat that provides cell type-specific genetic access to MOR-expressing cells. After performing anatomic and behavioral validation experiments, we used the Oprm1-Cre knock-in rats to study the involvement of NAc MOR-expressing cells in heroin self-administration in male and female rats. Using RNAscope, autoradiography, and FISH chain reaction (HCR-FISH), we found no differences in Oprm1 expression in NAc, dorsal striatum, and dorsal hippocampus, or MOR receptor density (except dorsal striatum) or function between Oprm1-Cre knock-in rats and wildtype littermates. HCR-FISH assay showed that iCre is highly coexpressed with Oprm1 (95%-98%). There were no genotype differences in pain responses, morphine analgesia and tolerance, heroin self-administration, and relapse-related behaviors. We used the Cre-dependent vector AAV1-EF1a-Flex-taCasp3-TEVP to lesion NAc MOR-expressing cells. We found that the lesions decreased acquisition of heroin self-administration in male Oprm1-Cre rats and had a stronger inhibitory effect on the effort to self-administer heroin in female Oprm1-Cre rats. The validation of an Oprm1-Cre knock-in rat enables new strategies for understanding the role of MOR-expressing cells in rat models of opioid addiction, pain-related behaviors, and other opioid-mediated functions. Our initial mechanistic study indicates that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in male and female rats.SIGNIFICANCE STATEMENT The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-based Oprm1-Cre knock-in transgenic rat that provides cell type-specific genetic access to brain MOR-expressing cells. After performing anatomical and behavioral validation experiments, we used the Oprm1-Cre knock-in rats to show that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in males and females. The new Oprm1-Cre rats can be used to study the role of brain MOR-expressing cells in animal models of opioid addiction, pain-related behaviors, and other opioid-mediated functions.

Irradiated riboflavin over nonradiated one: Potent antimigratory, antiproliferative and cytotoxic effects on glioblastoma cells.

Riboflavin is a water-soluble yellowish vitamin and is controversial regarding its effect on tumour cells. Riboflavin is a powerful photosensitizer that upon exposure to radiation, undergoes an intersystem conversion with molecular oxygen, leading to the production of ROS. In the current study, we sought to ascertain the impact of irradiated riboflavin on C6 glioblastoma cells regarding proliferation, cell death, oxidative stress and migration. First, we compared the proliferative behaviour of cells following nonradiated and radiated riboflavin. Next, we performed apoptotic assays including Annexin V and caspase 3, 7 and 9 assays. Then we checked on oxidative stress and status by flow cytometry and ELISA kits. Finally, we examined inflammatory change and levels of MMP2 and SIRT1 proteins. We caught a clear antiproliferative and cytotoxic effect of irradiated riboflavin compared to nonradiated one. Therefore, we proceeded with our experiments using radiated riboflavin. In all apoptotic assays, we observed a dose-dependent increase. Additionally, the levels of oxidants were found to increase, while antioxidant levels decreased following riboflavin treatment. In the inflammation analysis, we observed elevated levels of both pro-inflammatory and anti-inflammatory cytokines. Additionally, after treatment, we observed reduced levels of MMP2 and SIRT. In conclusion, radiated riboflavin clearly demonstrates superior antiproliferative and apoptotic effects on C6 cells at lower doses compared to nonradiated riboflavin.

Understanding the molecular mechanism of regeneration through apoptosis-induced compensatory proliferation studies - updates and future aspects.

AICP is a crucial process that maintaining tissue homeostasis and regeneration. In the past, cell death was perceived merely as a means to discard cells without functional consequences. However, during regeneration, effector caspases orchestrate apoptosis, releasing signals that activate stem cells, thereby compensating for tissue loss across various animal models. Despite significant progress, the activation of Wnt3a by caspase-3 remains a focal point of research gaps in AICP mechanisms, spanning from lower to higher regenerative animals. This inquiry into the molecular intricacies of caspase-3-induced Wnt3a activation contributes to a deeper understanding of the links between regeneration and cancer mechanisms. Our report provides current updates on AICP pathways, delineating research gaps and highlighting the potential for future investigations aimed at enhancing our comprehension of this intricate process.

Apoptosis and eryptosis: similarities and differences.

Eryptosis is a regulated cell death (RCD) of mature erythrocytes initially described as a counterpart of apoptosis for enucleated cells. However, over the recent years, a growing number of studies have emphasized certain differences between both cell death modalities. In this review paper, we underline the hallmarks of eryptosis and apoptosis and highlight resemblances and dissimilarities between both RCDs. We summarize and critically discuss differences in the impact of caspase-3, Ca2+ signaling, ROS signaling pathways, opposing roles of casein kinase 1α, protein kinase C, Janus kinase 3, cyclin-dependent kinase 4, and AMP-activated protein kinase to highlight a certain degree of divergence between apoptosis and eryptosis. This review emphasizes the crucial importance of further studies that focus on deepening our knowledge of cell death machinery and identifying novel differences between cell death of nucleated and enucleated cells. This might provide evidence that erythrocytes can be defined as viable entities capable of programmed cell destruction. Additionally, the revealed cell type-specific patterns in cell death can facilitate the development of cell death-modulating therapeutic agents.

Cleaved caspase-3 is present in the majority of glial cells in the intact rat spinal cord during postnatal life.

Cell death is an essential process that occurs during the development of the central nervous system. Despite the availability of a wide range of commercially produced antibodies against various apoptotic markers, data regarding apoptosis in intact spinal cord during postnatal development and adulthood are mostly missing. We investigated apoptosis in rat spinal cord at different stages of ontogenesis (postnatal days 8, 29, and 90). For this purpose, we applied immunofluorescent detection of two widely used apoptotic markers, cleaved caspase-3 (cC3) and cleaved poly(ADP-ribose) polymerase (cPARP). Surprisingly, we found significant discrepancy between the number of cC3+ cells and PARP+ cells, with a ratio between 500:1 and 5000:1 in rat spinal cord at all postnatal time points. The majority of cC3+ cells were glial cells and did not exhibit an apoptotic phenotype. In contrast with in vivo results, in vitro analysis of primary cell cultures derived from neonatal rat spinal cord and treated with the apoptotic inductor staurosporine revealed a similar onset of occurrence of both cC3 and cPARP in cells subjected to apoptosis. Gene expression analysis of spinal cord revealed elevated expression of the Birc4 (XIAP), Birc2, and Birc5 (Survivin) genes, which are known potent inhibitors of apoptosis. Our data indicate that cC3 is not an exclusive marker of apoptosis, especially in glial cells, owing its possible presence in inhibited forms and/or its participation in other non-apoptotic roles. Therefore, cPARP appears to be a more appropriate marker to detect apoptosis.

Exploring the induction of endometrial epithelial cell apoptosis in clinical-type endometritis in yaks through the cyt-c/caspase-3 signaling axis.

Endometritis is a significant contributor to reduced productivity in yaks in Tibet, China. The Cyt-c/Caspase-3 signaling axis plays a crucial role in the mitochondrial pathway that triggers cell apoptosis due to endogenous factors. In this study, we examined the endometrial epithelial tissue of yaks with endometritis using pathological examination, immunohistochemical analysis, TUNEL staining, qRT-PCR, and Western blot. The results indicated significant changes in the apoptotic factors of the Cyt-c/Caspase-3 signaling axis. The expression levels of Bak1, Bax, Cyt-c, Apaf-1, Caspase-9, and Caspase-3 were significantly increased (P < 0.05), while the expression level of Bcl-2 was significantly decreased. Immunohistochemistry results revealed significant increase in Bak1, Bax, Cyt-c, Apaf-1, Caspase-9, and Caspase-3 expression in the cytoplasm compared to the healthy group, except for Bcl-2, which showed a significant decrease. Pathological section analysis demonstrated that clinical endometritis in yaks led to structural damage, bleeding, congestion, and inflammatory cell infiltration in the endometrial epithelium. Our study findings indicated that clinical endometritis in yaks can modulate apoptosis of endometrial epithelial cells via the Cyt-c/Caspase-3 signaling pathway, resulting in different levels of damage. This research is pioneering in exploring cell apoptosis induced by clinical endometritis in yaks, offering novel insights and potential strategies for the future prevention and treatment of endometritis in yaks.

Ruthenium(II) complex with 2-mercaptothiazoline ligand induces selective cytotoxicity involving DNA damage and apoptosis in melanoma cells.

Melanoma is the most aggressive and lethal type of skin cancer due to its characteristics such as high metastatic potential and low response rate to existing treatment modalities. In this way, new drug prototypes are being studied to solve the problem of treating patients with melanoma. Among these, ruthenium-based metallopharmaceuticals may be promising alternatives due to their antitumor characteristics and low systemic toxicity. In this context, the present study evaluated the antineoplastic effect of the ruthenium complex [Ru(mtz)(dppe)2]PF6-2-mercaptothiazoline-di-1,2-bis(diphenylphosphine) ethaneruthenium(II), namely RuMTZ, on human melanoma (A-375) and murine (B16-F10) cells, considering different approaches. Through XTT colorimetric and clonogenic efficiency assays, the complex revealed the selective cytotoxic activity, with the lowest IC50 (0.4 µM) observed for A375 cells. RuMTZ also induced changes in cell morphology, increased cell population in the sub-G0 phase and inhibiting cell migration. The levels of γH2AX and cleaved caspase 3 proteins were increased in both cell lines treated with RuMTZ. These findings indicated that the cytotoxic activity of RuMTZ on melanoma cells is related, at least in part, to the induction of DNA damage and apoptosis. Therefore, RuMTZ exhibited promising antineoplastic activity against melanoma cells.

Effect of post-gastrulation exposure to acrylamide on chick embryonic development.

The critical developmental stages of the embryo are strongly influenced by the dietary composition of the mother. Acrylamide is a food contaminant that can form in carbohydrate-rich foods that are heat-treated. The aim of this study was to investigate the toxicity of a relatively low dose of acrylamide on the development of the neural tube in the early stage chick embryos. Specific pathogen-free fertilized eggs (n = 100) were treated with acrylamide (0.1, 0.5, 2.5, 12.5 mg/kg) between 28-30th hours of incubation and dissected at 48th hours. In addition to morphological and histopathological examinations, proliferating cell nuclear antigen (PCNA) and caspase 3 were analyzed immunohistochemically. The brain and reproductive expression gene (BRE) was analyzed by RT-PCR. Acrylamide exposure had a negative effect on neural tube status even at a very low dose (0.1 mg/kg) (p < 0.05). Doses of 0.5 mg/kg and above caused a delay in neural tube development (p < 0.05). Crown-rump length and somite count decreased dose-dependently, while this decrease was not significant in the very low dose group (p > 0.05), which was most pronounced at doses of 2.5 and 12.5 mg/kg (p < 0.001). Acrylamide exposure dose-dependently decreased PCNA and increased caspase 3, with this change being significant at doses of 0.5 mg/kg and above (p < 0.001). BRE was downregulated at all acrylamide exposures except in the very low dose group (0.1 mg/kg). In conclusion, we find that acrylamide exposure (at 0.5 mg/kg and above) in post-gastrulation delays neural tube closure in chicken embryos by suppressing proliferation and apoptosis induction and downregulating BRE gene expression.

Diphenyl Diselenide Through Reduction of Inflammation, Oxidative Injury and Caspase-3 Activation Abates Doxorubicin-Induced Neurotoxicity in Rats.

Neurotoxicity associated with chemotherapy is a debilitating side effect of cancer management in humans which reportedly involves inflammatory and oxidative stress responses. Diphenyl diselenide (DPDS) is an organoselenium compound which exhibits its anti-tumoral, anti-oxidant, anti-inflammatory and anti-mutagenic effects. Nevertheless, its possible effect on chemotherapy-induced neurotoxicity is not known. Using rat model, we probed the behavioral and biochemical effects accompanying administration of antineoplastic agent doxorubicin (7.5 mg/kg) and DPDS (5 and 10 mg/kg). Anxiogenic-like behavior, motor and locomotor insufficiencies associated with doxorubicin were considerably abated by both DPDS doses with concomitant enhancement in exploratory behavior as demonstrated by reduced heat maps intensity and enhanced track plot densities. Moreover, with exception of cerebral glutathione (GSH) level, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, biochemical data demonstrated reversal of doxorubicin-mediated decline in cerebral and cerebellar antioxidant status indices and the increase in acetylcholinesterase (AChE) activity by both doses of DPDS. Also, cerebellar and cerebral lipid peroxidation, hydrogen peroxide as well as reactive oxygen and nitrogen species levels were considerably diminished in rats administered doxorubicin and DPDS. In addition, DPDS administration abated myeloperoxidase activity, tumour necrosis factor alpha and nitric oxide levels along with caspase-3 activity in doxorubicin-administered rats. Chemoprotection of doxorubicin-associated neurotoxicity by DPDS was further validated by histomorphometry and histochemical staining. Taken together, DPDS through offsetting of oxido-inflammatory stress and caspase-3 activation elicited neuroprotection in doxorubicin-treated rats.

Modeling the heterogeneous apoptotic response of caspase-mediated signaling in tumor cells.

Resisting apoptosis is a hallmark of cancer. For this reason, it may be possible to force cancer cells to die by targeting components along the apoptotic signaling pathway. However, apoptosis signaling is challenging to understand due to dynamic and complex behaviors of ligands, receptors, and intracellular signaling components in response to cancer therapy. In this work, we forecast the apoptotic response based on the combined impact of these features. We expanded a previously established mathematical model of caspase-mediated apoptosis to include extracellular activation and receptor dynamics. In addition, three potential threshold values of caspase-3 necessary for the activation of apoptosis were selected to forecast which cells become apoptotic over time. We first vary ligand and receptor levels with the number of intracellular signaling proteins remaining consistent. Then, we vary the intracellular protein molecules in each simulated tumor cell to forecast the response of a heterogeneous population. By leveraging the benefits of computational modeling, we investigate the combined effect of several factors on the onset of apoptosis. This work provides quantitative insights for how the apoptotic signaling response can be forecasted, and precisely triggered, amongst heterogeneous cells via extracellular activation.

Mode of cell death in the penile cavernous tissue of type 1 diabetes mellitus rats.

BACKGROUND: Diabetes mellitus commonly causes endothelial cell and smooth muscle cell death in penile cavernous tissue. AIM: The study sought to study the mode of cell death in the penile cavernous tissue in type 1 diabetic rats. METHODS: A total of 36 Sprague Dawley rats 10 weeks of age were randomly divided into 2 groups: a normoglycemic group and type 1 diabetic group (intraperitoneal injection of Streptozotocin (STZ), 60 mg/kg). We randomly selected 6 rats from each group for tests at the end of 11, 14, and 18 weeks of age, respectively. All rats were able to eat and drink freely. The ratio of maximum intracavernous pressure to mean arterial pressure, concentration of serum testosterone, level of nitric oxide in the penile cavernosum, and expression of active caspase-1 (pyroptosis) and active caspase-3 (apoptosis) were determined. OUTCOMES: At the end of weeks 4 and 8 of type 1 diabetes, the proportions of endothelial cells and smooth muscle cells undergoing apoptosis and pyroptosis in penile cavernous tissue are different. RESULTS: The ratio of maximum intracavernous pressure to mean arterial pressure and nitric oxide levels were significantly lower in the 4- and 8-week diabetic groups than in the normoglycemic group (P < .01). Penile endothelial cell pyroptosis (5.67 ± 0.81%), smooth muscle cell apoptosis (23.72 ± 0.48%), total cell pyroptosis (9.67 ± 0.73%), and total apoptosis (10.52 ± 1.45%) were significantly greater in the 4-week diabetic group than in the normoglycemic group (P < .01). The proportion of endothelial cell pyroptosis (24.4 ± 3.69%), endothelial cell apoptosis (22.13 ± 2.43%), total cell pyroptosis (14.75 ± 0.93%), and total apoptosis (14.82 ± 1.08%) in the penile tissues of the 8-week diabetic group were significantly greater than those in the normoglycemic group (P < .01).The 8-week survival proportions of diabetic endothelial cells (38.86 ± 8.85%) and smooth muscle cells (44.46 ± 2.94%) was significantly lower than the 4-week survival proportions of endothelial cells (93.17 ± 8.07%) and smooth muscle cells (75.12 ± 4.76%) (P < .05). CLINICAL TRANSLATION: Inhibition of cell death by different methods at different stages may be the key to the treatment of type 1 diabetes-induced erectile dysfunction. STRENGTHS AND LIMITATIONS: The effect of type 1 diabetes on other types of cell death in penile cavernous tissue needs further study. CONCLUSION: The mode of death of endothelial cells in the cavernous tissue of the penis in the early stage in diabetic rats is dominated by pyroptosis, and the death of smooth muscle cells is dominated by apoptosis. Endothelial cell and smooth muscle cell death are not consistent at different stages of diabetes progression.