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Cisplatin-induced injury to renal proximal tubular cells stems from mitochondrial damage-induced apoptosis and inflammation. Dichloroacetate (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, a potential generator of ROS and ATP, protects against cisplatin-induced nephrotoxicity by promoting the TCA cycle. However, its effects on apoptotic pathways and ROS production in renal tubular cells remain unclear. Here, we investigated the detailed molecular mechanisms of the DCA's effects by immunoblot, RT-PCR, RNA-sequencing, and RNA-silencing in a murine renal proximal tubular (mProx) cell line and mouse kidneys. In mProx cells, DCA suppressed cisplatin-induced apoptosis by attenuating the JNK/14-3-3/Bax/caspase-9 and death receptor/ligand/caspase-8 pathways without impeding inflammatory signaling. RNA-sequencing demonstrated that DCA increased the cisplatin-reduced expression of cFLIP, a caspase-8 inactivator, and decreased the expression of almost all oxidative phosphorylation (OXPHOS) genes. DCA also increased NF-kB activation and ROS production, probably enhancing the cFLIP induction and OXPHOS gene reduction, respectively. Furthermore, cFLIP silencing weakened the DCA's anti-apoptotic effects. Finally, in mouse kidneys, DCA attenuated cisplatin-caused injuries such as functional and histological damages, caspase activation, JNK/14-3-3 activation, and cFLIP reduction. Conclusively, DCA mitigates cisplatin-induced nephrotoxicity by attenuating the JNK/14-3-3/Bax/caspase-9 pathway and inhibiting the caspase-8 pathways via cFLIP induction, probably outweighing the cisplatin plus DCA-derived cytotoxic effects including ROS. [ABSTRACT FROM AUTHOR]

Death receptor (DR) networks are controlled by the assembly of the Death-Inducing Signaling Complex (DISC) and complex II. The family of small molecules FLIPins (FLIP interactors) were developed to target the caspase-8/c-FLIPL heterodimer. FLIPin compounds were shown to promote apoptosis and caspase-8 activation at the DISC upon stimulation with death ligands (DLs) such as CD95L and TRAIL. To further investigate the role of FLIPin compounds in the DL-mediated cell death response, we analyzed their effects in combination with DLs and SMAC mimetics treatment. FLIPins were found to enhance cell viability loss and cell death induced by DL and SMAC mimetics in acute myeloid leukemia (AML), colon and pancreatic cancer cells. FLIPins enhanced both DL/BV6-induced apoptosis and DL/BV6/zVAD-fmk-induced necroptosis via an increase in complex II formation. Our results indicate that targeting the caspase-8/c-FLIPL heterodimer plays a prominent role in enhancing cell death induced by co-stimulation of DL/SMAC mimetics and opens new therapeutic strategies for targeting DR networks. [ABSTRACT FROM AUTHOR]

AbstractPurposeMethodsResultsConclusionThe purpose of this study was to investigate the role and mechanism of caspase-8 in the development of choroidal neovascularization induced by age-related macular degeneration, with the aim of identifying a potential therapeutic target for neovascular age-related macular degeneration.Mouse models of laser photocoagulation-induced choroidal neovascularization and hypoxic human choroidal endothelial cells were utilized to examine the involvement of caspase-8 in choroidal neovascularization development. The toll-like receptor 4/TIR domain-containing adaptor molecule 1/caspase-8 pathway was explored in hypoxic human choroidal endothelial cells to elucidate its contribution to pathological angiogenesis. Various experimental techniques, including inhibition assays and immunoblotting analysis, were employed to assess the effects and mechanisms of caspase-8 activation.Inhibition of caspase-8 demonstrated attenuated choroidal neovascularization development in mice subjected to laser photocoagulation. Activation of the toll-like receptor 4/TIR domain-containing adaptor molecule 1/caspase-8 pathway was observed in hypoxic human choroidal endothelial cells. Upon activation by the toll-like receptor 4/TIR domain-containing adaptor molecule 1 axis, caspase-8 directly cleaved caspase-1, leading to the cleavage of interleukin-1β and interleukin-18 by caspase-1. Consequently, activation of interleukin-1β and interleukin-18 through the toll-like receptor 4/TIR domain-containing adaptor molecule 1/caspase-8/caspase-1 pathway promoted the proliferative, migratory, and tube-forming abilities of hypoxic human choroidal endothelial cells.The findings of this study indicate that caspase-8 plays a crucial role in promoting choroidal neovascularization by activating interleukin-1β and interleukin-18 through the toll-like receptor 4/TIR domain-containing adaptor molecule 1/caspase-8/caspase-1 pathway in choroidal endothelial cells. Therefore, targeting caspase-8 may hold promise as a therapeutic approach for neovascular age-related macular degeneration. [ABSTRACT FROM AUTHOR]

Caspase-8, a renowned cysteine-aspartic protease within its enzyme family, initially garnered attention for its regulatory role in extrinsic apoptosis. With advancing research, a growing body of evidence has substantiated its involvement in other cell death processes, such as pyroptosis and necroptosis, as well as its modulatory effects on inflammasomes and proinflammatory cytokines. PANoptosis, an emerging concept of cell death, encompasses pyroptosis, apoptosis, and necroptosis, providing insight into the often overlapping cellular mortality observed during disease progression. The activation or deficiency of caspase-8 enzymatic activity is closely linked to PANoptosis, positioning caspase-8 as a key regulator of cell survival or death across various physiological and pathological processes. Aberrant expression of caspase-8 is closely associated with the development and progression of a range of inflammatory diseases, including immune system disorders, neurodegenerative diseases (NDDs), sepsis, and cancer. This paper delves into the regulatory role and impact of caspase-8 in these conditions, aiming to elucidate potential therapeutic strategies for the future intervention. [ABSTRACT FROM AUTHOR]

The incidence and mortality of breast cancer increase year by year, and it is urgent to find high-efficiency and low-toxicity anti-cancer drugs. Pterostilbene (PTE) is a natural product with antitumor activity, but the specific antitumor mechanism is not very clear. Aerobic glycolysis is the main energy supply for cancer cells. Pyroptosis is an inflammatory, programmed cell death. The aim of this study was to investigate the effect of PTE on glycolysis and pyroptosis in EMT6 and 4T1 cells and the specific mechanism, and to elucidate the role of pyruvate kinase 2 (PKM2), a key enzyme in glycolysis, in the antitumor role of PTE. Our study suggested that PTE induced pyroptosis by inhibiting tumor glycolysis. PKM2 played an important role in both the inhibition of glycolysis and the induction of pyroptosis by PTE. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusions Identifying the drive genes and inhibiting their significant signals were persistently the main concepts in cancer treatment. However, for oral cavity squamous cell carcinoma (OCSCC), the most influential genes for overall survival (OS) remain unclear.A total of 120 OCSCC patients with corresponding pathologic specimens were collected in Taiwan. Whole‐exome sequencing was done and the prognostic impact of each gene was analyzed. TCGA database was used to validate.The incidences of caspase‐8 mutation were 22.1% and 10.9% in the Taiwan and TCGA cohort, respectively. In the Taiwan cohort, caspase‐8 mutation was the most significant independent for OS with an adjusted hazard ratio (HR) ([95% CI]: 3.83 [1.84–7.99]). It was validated by the TCGA database (HR [95% CI]: 1.51 [1.00–2.29]). The 5‐year OSs of the patients with or without caspase‐8 mutation were 38.1% vs. 75.3% (p < 0.001) (HR [95% CI]: 3.264 [1.645–6.438]) in the Taiwan cohort, and 26.1% vs. 49.0% (p = 0.048) (1.513 [1.001–2.288]) in the TCGA cohorts, respectively. Caspase‐8 mutation was also individually associated with poor prognosis for TNM stage I/II/III/IV, respectively. CASP8 R127* and R494*, defined as pathogenic mutations in ClinVar, were presented in both cohorts.Caspase‐8 mutation was the most significant genetic alteration impacting prognosis. [ABSTRACT FROM AUTHOR]

Background: Breast cancer is the most diagnosed cancer in women. Its pathogenesis includes several pathways in cancer proliferation, apoptosis, and metastasis. Some clinical data have indicated the association between coffee consumption and decreased cancer risk. However, little data is available on the effect of coffee on breast cancer cells in vitro and in vivo. Methods: In our study, we assessed the effect of Turkish coffee and Fridamycin-H on different pathways in breast cancer, including apoptosis, proliferation, and oxidative stress. A human breast cancer cell line (MCF-7) was treated for 48 h with either coffee extract (5% or 10 v/v) or Fridamycin-H (10 ng/ml). Ehrlich solid tumors were induced in mice for in vivo modeling of breast cancer. Mice with Ehrlich solid tumors were treated orally with coffee extract in drinking water at a final concentration (v/v) of either 3%, 5%, or 10% daily for 21 days. Protein expression levels of Caspase-8 were determined in both in vitro and in vivo models using ELISA assay. Moreover, P-glycoprotein and peroxisome proliferator-activated receptor gamma (PPAR-γ) protein expression levels were analyzed in the in vitro model. β-catenin protein expression was analyzed in tumor sections using immunohistochemical analysis. In addition, malondialdehyde (MDA) serum levels were analyzed using colorimetry. Results: Both coffee extract and Fridamycin-H significantly increased Caspase-8, P-glycoprotein, and PPAR-γ protein levels in MCF-7 cells. Consistently, all doses of in vivo coffee treatment induced a significant increase in Caspase-8 and necrotic zones and a significant decrease in β- catenin, MDA, tumor volume, tumor weight, and viable tumor cell density. Conclusion: These findings suggest that coffee extract and Fridamycin-H warrant further exploration as potential therapies for breast cancer. [ABSTRACT FROM AUTHOR]

Abstract Cisplatin-induced injury to renal proximal tubular cells stems from mitochondrial damage-induced apoptosis and inflammation. Dichloroacetate (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, a potential generator of ROS and ATP, protects against cisplatin-induced nephrotoxicity by promoting the TCA cycle. However, its effects on apoptotic pathways and ROS production in renal tubular cells remain unclear. Here, we investigated the detailed molecular mechanisms of the DCA’s effects by immunoblot, RT-PCR, RNA-sequencing, and RNA-silencing in a murine renal proximal tubular (mProx) cell line and mouse kidneys. In mProx cells, DCA suppressed cisplatin-induced apoptosis by attenuating the JNK/14-3-3/Bax/caspase-9 and death receptor/ligand/caspase-8 pathways without impeding inflammatory signaling. RNA-sequencing demonstrated that DCA increased the cisplatin-reduced expression of cFLIP, a caspase-8 inactivator, and decreased the expression of almost all oxidative phosphorylation (OXPHOS) genes. DCA also increased NF-kB activation and ROS production, probably enhancing the cFLIP induction and OXPHOS gene reduction, respectively. Furthermore, cFLIP silencing weakened the DCA’s anti-apoptotic effects. Finally, in mouse kidneys, DCA attenuated cisplatin-caused injuries such as functional and histological damages, caspase activation, JNK/14-3-3 activation, and cFLIP reduction. Conclusively, DCA mitigates cisplatin-induced nephrotoxicity by attenuating the JNK/14-3-3/Bax/caspase-9 pathway and inhibiting the caspase-8 pathways via cFLIP induction, probably outweighing the cisplatin plus DCA-derived cytotoxic effects including ROS.

Abstract Caspase-8, a renowned cysteine-aspartic protease within its enzyme family, initially garnered attention for its regulatory role in extrinsic apoptosis. With advancing research, a growing body of evidence has substantiated its involvement in other cell death processes, such as pyroptosis and necroptosis, as well as its modulatory effects on inflammasomes and proinflammatory cytokines. PANoptosis, an emerging concept of cell death, encompasses pyroptosis, apoptosis, and necroptosis, providing insight into the often overlapping cellular mortality observed during disease progression. The activation or deficiency of caspase-8 enzymatic activity is closely linked to PANoptosis, positioning caspase-8 as a key regulator of cell survival or death across various physiological and pathological processes. Aberrant expression of caspase-8 is closely associated with the development and progression of a range of inflammatory diseases, including immune system disorders, neurodegenerative diseases (NDDs), sepsis, and cancer. This paper delves into the regulatory role and impact of caspase-8 in these conditions, aiming to elucidate potential therapeutic strategies for the future intervention.

Abstract Background Breast cancer is the most diagnosed cancer in women. Its pathogenesis includes several pathways in cancer proliferation, apoptosis, and metastasis. Some clinical data have indicated the association between coffee consumption and decreased cancer risk. However, little data is available on the effect of coffee on breast cancer cells in vitro and in vivo. Methods In our study, we assessed the effect of Turkish coffee and Fridamycin-H on different pathways in breast cancer, including apoptosis, proliferation, and oxidative stress. A human breast cancer cell line (MCF-7) was treated for 48 h with either coffee extract (5% or 10 v/v) or Fridamycin-H (10 ng/ml). Ehrlich solid tumors were induced in mice for in vivo modeling of breast cancer. Mice with Ehrlich solid tumors were treated orally with coffee extract in drinking water at a final concentration (v/v) of either 3%, 5%, or 10% daily for 21 days. Protein expression levels of Caspase-8 were determined in both in vitro and in vivo models using ELISA assay. Moreover, P-glycoprotein and peroxisome proliferator-activated receptor gamma (PPAR-γ) protein expression levels were analyzed in the in vitro model. β-catenin protein expression was analyzed in tumor sections using immunohistochemical analysis. In addition, malondialdehyde (MDA) serum levels were analyzed using colorimetry. Results Both coffee extract and Fridamycin-H significantly increased Caspase-8, P-glycoprotein, and PPAR-γ protein levels in MCF-7 cells. Consistently, all doses of in vivo coffee treatment induced a significant increase in Caspase-8 and necrotic zones and a significant decrease in β- catenin, MDA, tumor volume, tumor weight, and viable tumor cell density. Conclusion These findings suggest that coffee extract and Fridamycin-H warrant further exploration as potential therapies for breast cancer.

AbstractContext: Berberine (BBR) can regulate enteric glial cells (EGCs) and the gut vascular barrier (GVB).Objective: To explore whether BBR regulates GVB permeability via the S100B pathway.Materials and methods: GVB hyperpermeability in C57BL/6J mice was induced by burns or S100B enema. BBR (25 or 50 mg/kg/d, 3 d) was gavaged preburn. S100B monoclonal antibody (S100BmAb) was i.v. injected postburn. Mouse intestinal microvascular endothelial cells (MIMECs) were treated with S100B, S100B plus BBR, or Z-IETD-FMK. GVB permeability was assayed by FITC-dextran, S100B by ELISA, caspase-8, β-catenin, occludin and PV-1 by immunoblot.Results: Burns elevated S100B in serum and in colonic mucosa to a peak (147.00 ± 4.95 ng/mL and 160.30 ± 8.50 ng/mg, respectively) at 36 h postburn, but BBR decreased burns-induced S100B in serum (126.20 ± 6.30 or 90.60 ± 3.78 ng/mL) and in mucosa (125.80 ± 12.40 or 91.20 ± 8.54 ng/mg). Burns raised GVB permeability (serum FITC-dextran 111.40 ± 8.56 pg/mL) at 48 h postburn, but BBR reduced GVB permeability (serum FITC-dextran 89.20 ± 6.98 or 68.60 ± 5.50 ng/mL). S100B enema (1 μM) aggravated burns-raised GVB permeability (142.80 ± 8.07 pg/mL) and PV-1, but the effect of S100B was antagonized by BBR. Z-IETD-FMK (5 μM) increased S100B-induced permeability to FITC-dextran (205.80 ± 9.70 to 263.80 ± 11.04 AUs) while reducing β-catenin in MIMECs. BBR (5 μM) reduced S100B-induced permeability (104.20 ± 9.65 AUs) and increased caspase-8, β-catenin and occludin.Discussion and conclusion: BBR decreases burns-induced GVB hyperpermeability via modulating S100B/caspase-8/β-catenin pathway and may involve EGCs.

Epilepsy is one of the most frequently diagnosed neurological diseases, but the neurobiological basis of the disease remains poorly understood. Immunophenotyping CBA mice brain (NeuN and caspase-8) in parallel with hippocampal neurons’ functional status and survival rate assessment during acute epileptic PTZ-induced seizures is of particular interest. The aims of this study were to investigate the involvement of NeuN and caspase-8 in cell cycle regulation and the death of hippocampal neurons during PTZ-induced seizures in mice and to assess the therapeutic efficacy of Myricetin in the aforementioned experimental settings. Male CBA mice (n = 340) were divided into six groups to investigate the neuroprotective and antiepileptic effects of Myricetin and Valproic Acid in the PTZ-induced seizure model. Group I (control, n = 20) received a single intraperitoneal injection of NaCl 0.9% solution. Group II (PTZ only, n = 110) received a single intraperitoneal 45 mg/kg PTZ to induce seizures. Group III (Myricetin + PTZ, n = 90) was administered Myricetin orally at 200 mg/kg for 5 days, followed by a PTZ injection. Group IV (Valproic Acid + PTZ, n = 80) received intraperitoneal Valproic Acid at 100 mg/kg for 5 days, followed by PTZ. Group V (Myricetin + NaCl, n = 20) received Myricetin and NaCl. Group VI (Valproic Acid + NaCl, n = 20) received Valproic Acid and NaCl. Seizure severity was monitored using the modified Racine scale. Behavioral assessments included sensorimotor function tests, motor coordination using the rotarod test, and cognitive function via the Morris water maze. Brain tissues were collected and analyzed for oxidative stress markers, including malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Blood samples were analyzed for cytokine levels (IL-1β, IL-6, and TNF-α). Histological studies involved H&E and Nissl staining to evaluate general histopathology and neuronal density. Immunohistochemical analysis was conducted using antibodies against NeuN and caspase-8 to assess neuronal cell cycle regulation and apoptosis. PTZ-induced seizures caused significant oxidative stress and inflammation, leading to neuronal damage. Biochemical analyses showed elevated levels of MDA, SOD, GSH, IL-1β, IL-6, and TNF-α. Histological and immunohistochemical evaluations revealed a significant increase in caspase-8-positive neurons and a decrease in NeuN-positive neurons in the hippocampus and other brain regions, correlating with seizure severity. Myricetin and Valproic Acid treatments reduced oxidative stress markers and neuronal damage. Both treatments resulted in moderate neuronal protection, with fewer damaged neurons observed in the hippocampus, dentate gyrus, and other brain areas compared to the PTZ-only group. Summarizing, Myricetin administration showed promising neuroprotective effects. It significantly reduced oxidative stress markers, including MDA, and restored antioxidant enzyme activities (SOD and GSH), suggesting its antioxidative potential. Myricetin also effectively attenuated the elevation of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, indicating strong anti-inflammatory properties. Behavioral assessments revealed that Myricetin improved cognitive and motor functions in PTZ-treated mice, with notable reductions in seizure severity and mortality rates. Histological analyses supported these behavioral findings, with Nissl staining showing reduced neuronal damage and NeuN staining indicating better preservation of neuronal integrity in Myricetin-treated groups. Additionally, caspase-8 staining suggested a significant reduction in neuronal apoptosis.

Black rice bran (BRB) is well-known for its high antioxidant activity and its pivotal role in preventing colon cancer. The present study aims to investigate the effects of BRB administration on BALB/C mice induced with azoxymethane (AOM) and dextran sodium sulphate (DSS). The 24 mice were divided into three groups: the group induced by colon cancer (C+), the group induced by cancer and given the BRB diet (C+BRB), and the normal group (C−). Both the C− and C+ groups were given a standard AIN-93 M diet containing cellulose fiber. After 16 weeks, the mice were anesthetized, and the colonic tissue was identified for nodule distribution, histopathological observation, and mRNA expression analysis of proliferating cell nuclear antigen (PCNA), caspase-3, and caspase-8 genes using qRT PCR technique. Nodule distribution in the C+BRB group showed a significant decrease compared to the C+ group, with 1.65 ± 0.71 nodule/cm2 vs. 5.73 ± 2.93 nodule/cm2. Then, the colon weight was significantly decreased in the C+BRB group, at 0.19 ± 0.04 (g) compared to 0.25 ± 0.03 (g) in the C+ group. Also, the BRB diet in the C+BRB group significantly decreased PCNA mRNA expression compared to the C+ group, with values of 0.58 ± 0.09-fold change vs. 5.22 ± 0.80-fold change. Conversely, increased the mRNA expression of caspase-3 (0.91 ± 0.20-fold change vs. 0.36 ± 0.15-fold change) and caspase-8 (0.51 ± 0.18-fold change vs. 0.13 ± 0.31-fold change). In conclusion, administration of BRB inhibited the rate of cancer development by suppressing cancer cell proliferation and inducing apoptosis.

Enterovirus D68 (EV-D68) infection causes severe acute respiratory infection and severe neurological complications, such as acute flaccid myelitis (AFM), in children. However, although EV-D68 has pandemic potential, no effective drugs or vaccines are currently clinically available. Furthermore, EV-D68 infection-induced inflammatory response and cell death are not fully understood. In this study, we demonstrated that several inflammatory cytokines were upregulated in a multiplicity of infection (MOI) dependent manner in EV-D68-infected human rhabdomyosarcoma (RD) cells. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) confirmed that tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), C-C motif chemokine ligand-5 (CCL-5), and CXC motif chemokine ligand-5 (CXCL-5) mRNA levels were highly upregulated after EV-D68 infection. IL-1β processing and maturation mediated by caspase-8 was inhibited by the caspase-8 inhibitor Z-IETD-FMK. EV-D68 infection activates caspase-8 to mediate IL-1β maturation and secretion. Additionally, EV-D68 activated cell death-related proteins such as caspase-3, poly (ADP-ribose) polymerase 1 (PARP-1), phosphorylation of Mixed Lineage Kinase domain-like protein (pMLKL), and gasdermin E (GSDME). Thus, EV-D68 infection activates caspase-8, which triggers the necroptosis and apoptosis pathways. Overall, our data suggest that caspase-8 activation is associated with the inflammatory response and cell death in EV-D68-infected RD cells. This mechanism represents a novel target for the treatment of EV-D68 infection by inhibiting caspase-8 activation.

Aging is an irresistible natural law of the progressive decline of body molecules, organs, and overall function with the passage of time, resulting in eventual death. World Health Organization data show that aging is correlated with a wide range of common chronic diseases in the elderly, and is an essential driver of many diseases. Panax Ginseng C.A Meyer is an ancient herbal medicine, which has an effect of "long service, light weight, and longevity" recorded in the ancient Chinese medicine book "Compendium of Materia Medica." Ginsenoside Rg2, the main active ingredient of ginseng, also exerts a marked effect on the treatment of liver injury. However, it remains unclear whether Rg2 has the potential to ameliorate aging-induced liver injury. Hence, exploring the hepatoprotective properties of Rg2 and its possible molecular mechanism by Senescence Accelerate Mouse Prone 8 (SAMP8) and gut microbiota. Our study demonstrated that Rg2 can inhibit pyroptosis and apoptosis through caspase 8, and regulate the gut-liver axis to alleviate liver inflammation by changing the composition of gut microbiota, thus improving aging-induced liver injury. These findings provide theoretical support for the pharmacological effects of ginsenosides in delaying aging-induced liver injury. [ABSTRACT FROM AUTHOR]

The innate immune system serves as the first line of defense against β-coronaviruses (β-CoVs), a family of viruses that includes SARS-CoV-2. Viral sensing via pattern recognition receptors triggers inflammation and cell death, which are essential components of the innate immune response that facilitate viral clearance. However, excessive activation of the innate immune system and inflammatory cell death can result in uncontrolled release of proinflammatory cytokines, resulting in cytokine storm and pathology. PANoptosis, innate immune, inflammatory cell death initiated by innate immune sensors and driven by caspases and RIPKs through PANoptosome complexes, has been implicated in the pathology of viral infections. Therefore, understanding the molecular mechanisms regulating PANoptosis in response to β-CoV infection is critical for identifying new therapeutic targets that can mitigate disease severity. In the current study, we analyzed findings from a cell death-based CRISPR screen with archetypal β-CoV mouse hepatitis virus (MHV) as the trigger to characterize host molecules required for inflammatory cell death. As a result, we identified SMARCA4, a chromatin regulator, as a putative host factor required for PANoptosis in response to MHV. Furthermore, we observed that gRNA-mediated deletion of Smarca4 inhibited MHV-induced PANoptotic cell death in macrophages. These findings have potential translational and clinical implications for the advancement of treatment strategies for β-CoVs and other infections. [ABSTRACT FROM AUTHOR]

The inflammatory response is tightly regulated to eliminate invading pathogens and avoid excessive production of inflammatory mediators and tissue damage. Caspase‐8 is a cysteine protease that is involved in programmed cell death. Here we show the TRIF‐RIPK1‐Caspase‐8 is required for LPS‐induced CYLD degradation in macrophages. TRIF functions in the upstream of RIPK1. The homotypic interaction motif of TRIF and the death domain of RIPK1 are essential for Caspase‐8 activation. Caspase‐8 cleaves CYLD and the D235A mutant is resistant to the protease activity of Caspase‐8. TRIF and RIPK1 serve as substrates of Capase‐8 in vitro. cFLIP interacts with Caspase‐8 to modulate its protease activity on CYLD and cell death. Deficiency in TRIF, Caspase‐8 or CYLD can lead to a decrease or increase in the expression of genes encoding inflammatory cytokines. Together, the TRIF‐Caspase‐8 and CYLD play opposite roles in the regulation of TLR4 signalling. [ABSTRACT FROM AUTHOR]

Black rice bran (BRB) is well-known for its high antioxidant activity and its pivotal role in preventing colon cancer. The present study aims to investigate the effects of BRB administration on BALB/C mice induced with azoxymethane (AOM) and dextran sodium sulphate (DSS). The 24 mice were divided into three groups: the group induced by colon cancer (C+), the group induced by cancer and given the BRB diet (C+BRB), and the normal group (C−). Both the C− and C+ groups were given a standard AIN-93 M diet containing cellulose fiber. After 16 weeks, the mice were anesthetized, and the colonic tissue was identified for nodule distribution, histopathological observation, and mRNA expression analysis of proliferating cell nuclear antigen (PCNA), caspase-3, and caspase-8 genes using qRT PCR technique. Nodule distribution in the C+BRB group showed a significant decrease compared to the C+ group, with 1.65 ± 0.71 nodule/cm2 vs. 5.73 ± 2.93 nodule/cm2. Then, the colon weight was significantly decreased in the C+BRB group, at 0.19 ± 0.04 (g) compared to 0.25 ± 0.03 (g) in the C+ group. Also, the BRB diet in the C+BRB group significantly decreased PCNA mRNA expression compared to the C+ group, with values of 0.58 ± 0.09-fold change vs. 5.22 ± 0.80-fold change. Conversely, increased the mRNA expression of caspase-3 (0.91 ± 0.20-fold change vs. 0.36 ± 0.15-fold change) and caspase-8 (0.51 ± 0.18-fold change vs. 0.13 ± 0.31-fold change). In conclusion, administration of BRB inhibited the rate of cancer development by suppressing cancer cell proliferation and inducing apoptosis. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the effect of 3',4'-dihydroxyflavonol (DiOHF) on apoptosis in the cerebellum and hippocampus in rats with ischemia-reperfusion. A total of 38 Wistar albino male rats were used. Experimental groups were designed as Group 1-Sham; Group 2-Ischemia-reperfusion (IR), in which animals were anesthetized and carotid arteries ligated for 30 minutes (ischemia) and reperfused 30 minutes; Group 3- IR + DiOHF (10 mg/kg); Group 4- Ischemia + DiOHF (10 mg/kg) + reperfusion; Group 5-DiOHF + IR. DiOHF was supplemented as 10 mg/kg by intraperitoneal injection 30 minutes before IR. Following application, the animals were sacrificed under general anesthetic by cervical dislocation, and the cerebellum and hippocampus tissues were analyzed for apoptosis. IR significantly increased hippocampus and cerebellum apoptosis activity, confirmed by Hematoxylin-Eosin, TUNEL labeling, and Caspase-8 activity. However, these values were significantly suppressed by the administration of DiOHF, especially when used before the ischemia and reperfusion. The results of the study show that increased apoptosis in the cerebellum and hippocampus tissue was inhibited by intraperitoneal DiOHF supplementation. [ABSTRACT FROM AUTHOR]

Death receptor (DR) networks are controlled by the assembly of the Death-Inducing Signaling Complex (DISC) and complex II. The family of small molecules FLIPins (FLIP interactors) were developed to target the caspase-8/c-FLIPL heterodimer. FLIPin compounds were shown to promote apoptosis and caspase-8 activation at the DISC upon stimulation with death ligands (DLs) such as CD95L and TRAIL. To further investigate the role of FLIPin compounds in the DL-mediated cell death response, we analyzed their effects in combination with DLs and SMAC mimetics treatment. FLIPins were found to enhance cell viability loss and cell death induced by DL and SMAC mimetics in acute myeloid leukemia (AML), colon and pancreatic cancer cells. FLIPins enhanced both DL/BV6-induced apoptosis and DL/BV6/zVAD-fmk-induced necroptosis via an increase in complex II formation. Our results indicate that targeting the caspase-8/c-FLIPL heterodimer plays a prominent role in enhancing cell death induced by co-stimulation of DL/SMAC mimetics and opens new therapeutic strategies for targeting DR networks.

AbstractBackground Hyperthermia can play a synergistic role with chemotherapy in combination therapy. Although the association between caspase activation, apoptosis, and pyroptosis have been published for both cisplatin (CDDP) and hyperthermia therapies independently, the interactions between these molecular pathways in combination therapy are unknown. The present study aimed to investigate the possible interactions between caspase 8 activation, apoptosis, and pyroptosis in combination therapy.Methods Cells were treated with CDDP (15 µg/ml), followed by hyperthermia at optimized temperature (42.5 °C) in water-bath. After combination therapy, cell viability was analyzed by CCK-8, and cell death was analyzed by Annexin-V-FITC/PI and caspases activation. Immuno-staining and co-immuno-precipitation were used to examine the interaction between p62 and caspase-8. Pyroptosis was investigated by western blotting and transmission electron microscopy. E3 ligase Cullin 3 was knockdown by siRNA. In addition, caspase-8 activation was modulated by CRISPR-Cas9 gene-editing or pharmacological inhibition.Results Combination therapy promoted K63-linked polyubiquitination of caspase-8 and cellular accumulation of caspase-8. In turn, polyubiquitinated caspase-8 interacted with p62 and led to the activation of caspase-3. Knockdown of the E3 ligase Cullin 3 by siRNA reduced caspase-8 polyubiquitination and activation. In addition, combination therapy induced release of the pore-forming N-terminus from gasdermins and promoted pyroptosis along with caspase-8 accumulation and activation. Knockdown of caspase-8 by CRISPR/Cas9 based gene editing reduced the sensitivity of tumor cells to apoptosis and pyroptosis.Conclusions Our study presented a novel mechanism in which hyperthermia synergized with chemotherapy in promoting apoptosis and pyroptosis in a caspase-8 dependent manner.

Breast cancer is the second leading contributor to the age-standardized mortality rate, for both sexes and all ages worldwide. In Europe and the United States, it is the second leading cause of mortality, with an incidence rate of about 2.6 million cases per year. Noscapine, a well-known alkaloid used as a cough suppressant, demonstrated anti-tumor effects by triggering apoptosis in various cancer cell lines and has the potential to become another ally against breast, ovarian, colon, and gastric cancer, among other types of malignancy. Apoptosis plays a crucial role in the treatment of cancer. Noscapine affected BAX, CASP8, CASP9, NFKBIA, and RELA gene and protein expression in the MCF-7 and MDA-MB-231 cell lines. Gene expression was higher in tumor than in normal tissue, including the BAX expression levels in lung, ovary, endometrium, colon, stomach, and glioblastoma patients; BCL2L1 expression in endometrium, colon, and stomach patients; CASP8 gene expression levels in lung, endometrium, colon, stomach, and glioblastoma patients; RELA in colon, stomach, and glioblastoma patients; and NFKBIA in glioblastoma patients. It can be concluded that noscapine affected genes and proteins related to apoptosis in cancer cell lines and several types of cancer patients. [ABSTRACT FROM AUTHOR]

Temporomandibular joint osteoarthritis (TMJOA), prevalent in adolescents and the elderly, has serious physical and psychological consequences. TMJOA is a degenerative disease of the cartilage and bone, mostly driven by inflammation, and synoviocytes are the first and most important inflammatory factor releasers. Receptor‐interacting serine/threonine‐protein kinase (RIPK1) promotes inflammatory response and cell death during an array of illnesses. This research aimed to explore the impacts of RIPK1 inhibitor therapy in TMJOA and the mechanism of RIPK1 in inducing inflammation during TMJOA. Herein, inhibition of RIPK1 suppressed the elevated levels of inflammatory factors, nuclear factor kappa B (NF‐κB), along with markers of apoptosis and necroptosis after tumour necrosis factor (TNF)‐α/cycloheximide (CHX) treatment in synoviocytes. Moreover, inflammation models were constructed in vivo through complete Freund's adjuvant (CFA) induction and disc perforation, and the findings supported that RIPK1 inhibition protected TMJ articular cartilage against progressive degradation. RIPK1 regulates NF‐κB activation via cellular inhibitor of apoptosis proteins (cIAP), apoptosis via caspase‐8, and necroptosis via RIPK3/mixed lineage kinase domain‐like (MLKL) in synoviocytes, which in turn facilitates TMJOA inflammation progression. [ABSTRACT FROM AUTHOR]

Qingcong Zheng,1,&ast; Du Wang,2,&ast; Rongjie Lin,3,&ast; Yuchao Chen,4 Zixing Xu,1 Weihong Xu1 1Department of Orthopedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, People’s Republic of China; 2Arthritis Clinical and Research Center, Peking University People’s Hospital, Beijing, People’s Republic of China; 3Department of Orthopedic Surgery, Fujian Medical University Union Hospital, Fuzhou, People’s Republic of China; 4Department of Paediatrics, Fujian Provincial Hospital South Branch, Fuzhou, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zixing Xu; Weihong Xu, Email xuzixing@fjmu.edu.cn; xuweihong815@126.comBackground: Rheumatoid arthritis (RA) is one of the most common chronic inflammatory autoimmune diseases. However, the underlying molecular mechanisms of its pathogenesis are unknown. This study aimed to identify the common biomarkers of ferroptosis and pyroptosis in RA and screen potential drugs.Methods: The RA-related differentially expressed genes (DEGs) in GSE55235 were screened by R software and intersected with ferroptosis and pyroptosis gene libraries to obtain differentially expressed ferroptosis-related genes (DEFRGs) and differentially expressed pyroptosis-related genes (DEPRGs). We performed Gene Ontology (GO), Kyoto Encyclopedia of the Genome (KEGG), ClueGO, and Protein-Protein Interaction (PPI) analysis for DEFRGs and DEPRGs and validated them by machine learning. The microRNA/transcription factor (TF)-hub genes regulatory network was further constructed. The key gene was validated using the GSE77298 validation set, cellular validation was performed in in vitro experiments, and immune infiltration analysis was performed using CIBERSORT. Network pharmacology was used to find key gene-targeting drugs, followed by molecular docking and molecular dynamics simulations to analyze the binding stability between small-molecule drugs and large-molecule proteins.Results: Three hub genes (CASP8, PTGS2, and JUN) were screened via bioinformatics, and the key gene (CASP8) was validated and obtained through the validation set, and the diagnostic efficacy was verified to be excellent through the receiver operating characteristic (ROC) curves. The ferroptosis and pyroptosis phenotypes were constructed by fibroblast-like synoviocytes (FLS), and caspase-8 was detected and validated as a common biomarker for ferroptosis and pyroptosis in RA, and quercetin can reduce caspase-8 levels. Quercetin was found to be a potential target drug for caspase-8 by network pharmacology, and the stability of their binding was further verified using molecular docking and molecular dynamics simulations.Conclusion: Caspase-8 is an important biomarker for ferroptosis and pyroptosis in RA, and quercetin is a potential therapy for RA via targeting caspase-8 through ferroptosis and pyroptosis.Keywords: rheumatoid arthritis, ferroptosis, pyroptosis, caspase-8, quercetin

The incidence and mortality of breast cancer increase year by year, and it is urgent to find high-efficiency and low-toxicity anti-cancer drugs. Pterostilbene (PTE) is a natural product with antitumor activity, but the specific antitumor mechanism is not very clear. Aerobic glycolysis is the main energy supply for cancer cells. Pyroptosis is an inflammatory, programmed cell death. The aim of this study was to investigate the effect of PTE on glycolysis and pyroptosis in EMT6 and 4T1 cells and the specific mechanism, and to elucidate the role of pyruvate kinase 2 (PKM2), a key enzyme in glycolysis, in the antitumor role of PTE. Our study suggested that PTE induced pyroptosis by inhibiting tumor glycolysis. PKM2 played an important role in both the inhibition of glycolysis and the induction of pyroptosis by PTE.

Simple Summary: Despite the recent advancement in the treatment of ovarian cancer, it continues to be a largely incurable disease, plagued by de novo and acquired resistance to standard chemotherapeutics and novel second-line therapeutics. Therefore, identifying novel biomarkers and resistance mechanisms is critical to overcoming resistance, developing newer treatment strategies, and improving patient survival. In this study, we have demonstrated that low Caspase-8 expression correlates with poor prognosis in ovarian cancer patients. Moreover, the lack of Caspase-8 alters transcriptional regulation in ovarian cancer cells. In Caspase-8 knockout cells, increased BRD4 expression, increased CDK9 activity, and resistance to Carboplatin and Paclitaxel were observed. We have also shown that combining BRD4 inhibitors with Carboplatin, Paclitaxel, and CDK9 inhibitors synergistically sensitized these cells to undergo cell death. Ovarian cancer is one of the most lethal gynecological cancers worldwide, with approximately 70% of cases diagnosed in advanced stages. This late diagnosis results from the absence of early warning symptoms and is associated with an unfavorable prognosis. A standard treatment entails a combination of primary chemotherapy with platinum and taxane agents. Tumor recurrence following first-line chemotherapy with Carboplatin and Paclitaxel is detected in 80% of advanced ovarian cancer patients, with disease relapse occurring within 2 years of initial treatment. Platinum-resistant ovarian cancer is one of the biggest challenges in treating patients. Second-line treatments involve PARP or VEGF inhibitors. Identifying novel biomarkers and resistance mechanisms is critical to overcoming resistance, developing newer treatment strategies, and improving patient survival. In this study, we have determined that low Caspase-8 expression in ovarian cancer patients leads to poor prognosis. High-Grade Serous Ovarian Cancer (HGSOC) cells lacking Caspase-8 expression showed an altered composition of the RNA Polymerase II-containing transcriptional elongation complex leading to increased transcriptional activity. Caspase-8 knockout cells display increased BRD4 expression and CDK9 activity and reduced sensitivities to Carboplatin and Paclitaxel. Based on our work, we are proposing three potential therapeutic approaches to treat advanced ovarian cancer patients who exhibit low Caspase-8 expression and resistance to Carboplatin and/or Paclitaxel—combinations of (1) Carboplatin with small-molecule BRD4 inhibitors; (2) Paclitaxel with small-molecule BRD4 inhibitors, and (3) small-molecule BRD4 and CDK9 inhibitors. In addition, we are also proposing two predictive markers of chemoresistance—BRD4 and pCDK9. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) represents a promising anticancer agent, as it selectively induces apoptosis in transformed cells without altering the cellular machinery of healthy cells. Unfortunately, the presence of TRAIL resistance mechanisms in a variety of cancer types represents a major hurdle, thus limiting the use of TRAIL as a single agent. Accumulating studies have shown that TRAIL-mediated apoptosis can be facilitated in resistant tumors by combined treatment with antitumor agents, ranging from synthetic molecules to natural products. Among the latter, flavonoids, the most prevalent polyphenols in plants, have shown remarkable competence in improving TRAIL-driven apoptosis in resistant cell lines as well as tumor-bearing mice with minimal side effects. Here, we summarize the molecular mechanisms, such as the upregulation of death receptor (DR)4 and DR5 and downregulation of key anti-apoptotic proteins [e.g., cellular FLICE-inhibitory protein (c-FLIP), X-linked inhibitor of apoptosis protein (XIAP), survivin], underlying the TRAIL-sensitizing properties of different classes of flavonoids (e.g., flavones, flavonols, isoflavones, chalcones, prenylflavonoids). Finally, we discuss limitations, mainly related to bioavailability issues, and future perspectives regarding the clinical use of flavonoids as adjuvant agents in TRAIL-based therapies. [ABSTRACT FROM AUTHOR]

Purpose: Our study aims to investigate the effects of intracameral carbachol on oxidative stress and apoptosis in rat corneas. Methods: In this experimental study, 28 Wistar albino male rats were used. There were 9 rats in the carbachol group, 9 in the balanced salt solution (BSS) group, and 10 in the sham group. The carbachol group was injected with 0.01 cc of carbachol, and 0.01 cc of BSS was injected intracamerally into the BSS group. No drug was injected into the sham group, but the anterior chamber was entered with an empty syringe. Blood serum samples and corneas of rats were taken 1 week later. Caspase-3 and caspase-8 were immunohistochemically examined in rat corneal endothelial to investigate apoptosis. To determine oxidative stress in corneal endothelial tissue and serum, total antioxidant status (TAS), total oxidant stress (TOS), oxidative stress index (OSI), arylesterase (ARES), and paraoxonase (PON) levels were measured. Results: The mean OSI values in the rat serum of the carbachol group were significantly lower than those of the sham and BSS groups (P = 0.05 and P = 0.004, respectively). The mean TOS value of the carbachol group’s rat serum was significantly lower than the mean of the BSS group (P = 0.001). There was no significant difference in the mean TAS, TOS, OSI, ARES, and PON levels from the rat cornea of the carbachol, BSS, and sham groups (P > 0.05). All corneas in the carbachol group were caspase-3 negative, and a statistically significant difference was found among the sham, BSS, and carbachol groups (P = 0.002). No significant difference was observed among the sham, BSS, and carbachol corneas in caspase-8 staining (P = 0.094). Conclusion: Our study demonstrates that intracameral carbachol is a safe intracameral drug. Carbachol reduced oxidative stress in rat serum compared to rats injected with BSS and the sham group. In addition, carbachol did not increase oxidative stress in rat corneas compared to the BSS and sham groups. Similarly, immunohistochemical examination showed that car)bachol did not increase apoptosis in rat corneas and had a protective effect. [ABSTRACT FROM AUTHOR]

Background. Preservation and restoration of neurons in the ischemic penumbra by developing new methods for neuroprotection is one of the urgent issues of modern medicine. The purpose was to study the effect of different combinations of neuroprotectors with different mechanisms of action by analyzing markers of inflammation, endothelial dysfunction, and apoptosis in the blood serum of patients with ischemic stroke. Materials and methods. A randomized prospective controlled study was conducted on the use of neuroprotective complexes (NPC): NPC 1 (cerebrolysin + mexidol) and NPC 2 (cerebrolysin + citicoline), in patients with moderate and severe ische-mic stroke. They were randomly divided into groups: 1) comparison group — standard therapy; 2) NPC 1 along with standard treatment; 3) NPC 2 against the background of standard treatment. Laboratory studies on assessing interleukin-6, endothelin-1 and caspase-8 in blood serum were performed in dynamics, on days 1, 4 and 7. Results. In terms of anti-inflammatory activity, the therapy scheme, which included the administration of NPС 2, was 1.6–2.1 times (p

Aim. To study the regulation of apoptosis in the endometrium of women with chronic endometritis (CE) and external genital endometriosis (EGE) based on the study of the expression of its regulators such as transcription factor (NF-), Bcl-2 and Caspase-8. Materials and methods. The study evaluated the expression of apoptosis factors such as Caspase-8, NF-B transcription factor, and Bcl-2, in patients with chronic endometritis (CE, n=23), external genital endometriosis (EGE, n=20), and intact endometrium (control group; n=7). Statistically significant differences were found for all test markers (p0.05). Results. The increased expression of apoptosis factors is probably related to high endometrial pro-inflammatory activity in both CE and EGE. For EGE, this effect is more pronounced at the transcription level in the form of an increase in the expression of the transcription factor NF-B in both glandular and stromal endometrial cells. It is probably due to the systemic nature of the chronic inflammatory process. For CE, despite the antiapoptotic activity of Bcl-2, an increase in Caspase-8 expression in the endometrium may also indicate a predominance of innate immunity activation. Conclusion. The imbalance of pro- and antiapoptotic factors can be an inducer of both cytotoxic and cytoprotective mechanisms of EGE and CE. However, it requires further research.

Darbeli Elektromanyetik Alan (PEMF) düşük frekanslı elektromanyetik alan olup son yıllarda klinik araştırmalarda tedavi amaçlı uygulanmasına yönelik çalışmalar hız kazanmıştır. Farklı frekans, yoğunluk, dalga boyu ve sürelerde kematerapötik ilaçlarla birlikte uygulanan PEMF maruziyetinin beyin kanseri hücreleri dahil çeşitli kanser hücrelerinde apoptoz üzerine etkilerini değerlendiren çalışmalardan farklı olarak çalışmada sabit frekans ve yoğunlukta (50 Hz, 1 mT) uzun süre (48 saat) PEMF maruziyetinin SK-N-SH insan nöroblastoma hücresinde apoptoz mekanizmasına olası etkileri farklı tekniklerle araştırılmıştır. Hücreler kontrol grubu, PEMF maruziyetinin olmadığı SK-N-SH hücre grubu, ve PEMF’ye 48 saat maruz bırakılan SK-N-SH hücre grubu olmak üzere üçe ayrılmıştır. Hücre canlılığı, apoptoz tayini, kaspaz-8 mRNA düzeyi ve kaspaz-8 protein ekspresyonu sırasıyla alamar mavisi, akış sitometri, qRT-PCR ve Western-Blot teknikleriyle belirlenmiştir. Uzun süreli PEMF maruziyetinin insan nöroblastoma hücresinde hücre canlılığını belirgin şekilde azaltıp hücreleri daha fazla erken apoptoza uğratarak hücreleri apoptoza sürüklediği ve bu mekanizmanın kaspaz-8 mRNA düzeyinde ve protein ekspresyon seviyesinde artışla ilişkili olabileceği gösterilmiştir.

ABSTRACTSopF, a newly discovered effector secreted by Salmonella pathogenicity island-1 type III secretion system (T3SS1), was reported to target phosphoinositide on host cell membrane and aggravate systemic infection, while its functional relevance and underlying mechanisms have yet to be elucidated. PANoptosis (pyroptosis, apoptosis, and necroptosis) of intestinal epithelial cells (IECs) has been characterized as a pivotal host defense to limit the dissemination of foodborne pathogens, whereas the effect of SopF on IECs PANoptosis induced by Salmonella is rather limited. Here, we show that SopF can attenuate intestinal inflammation and suppress IECs expulsion to promote bacterial dissemination in mice infected with Salmonella enterica serovar Typhimurium (S. Typhimurium). We revealed that SopF could activate phosphoinositide-dependent protein kinase-1 (PDK1) to phosphorylate p90 ribosomal S6 kinase (RSK) which down-regulated Caspase-8 activation. Caspase-8 inactivated by SopF resulted in inhibition of pyroptosis and apoptosis, but promotion of necroptosis. The administration of both AR-12 (PDK1 inhibitor) and BI-D1870 (RSK inhibitor) potentially overcame Caspase-8 blockade and subverted PANoptosis challenged by SopF. Collectively, these findings demonstrate that this virulence strategy elicited by SopF aggregates systemic infection via modulating IEC PANoptosis through PDK1-RSK signaling, which throws light on novel functions of bacterial effectors, as well as a mechanism employed by pathogens to counteract host immune defense.

The canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) pathway involves a priming step to induce pro-IL-1β followed by a secondary signal such as K+ efflux to activate inflammasome formation. This then leads to the maturation of IL-1β and the formation of gasdermin D (GSDMD) pores that initiate pyroptosis and mediate IL-1β release. In contrast, primary human monocytes also engage an alternative pathway in response to toll-like receptor (TLR) 4 activation, without the need for a secondary signal. Data from a monocyte-like cell line suggest that the alternative pathway functions via the TLR adaptor protein TIR-domain-containing adapter-inducing interferon-b (TRIF), receptor-interacting protein kinase 1 (RIPK1), FAS-associated death domain (FADD) and caspase-8 upstream of NLRP3 activation, but in the absence of K+ efflux or pyroptosis. Usage of the alternative pathway by other members of the TLR family that induce IL-1β but do not signal through TRIF, has yet to be explored in primary human monocytes. Furthermore, the mechanism by which IL-1β is released from monocytes remains unclear. Therefore, this study investigated if the alternative NLRP3 inflammasome pathway is initiated following activation of TLRs other than TLR4, and if GSDMD was necessary for the release of IL-1β. Monocytes were stimulated with ligands that activate TLR1/2, TLR2/6, TLR4 and TLR7 and/or TLR8 (using a dual ligand). Similar to TLR4, all of the TLRs investigated induced IL-1β release in a NLRP3 and caspase-1 dependent manner, indicating that TRIF may not be an essential upstream component of the alternative pathway. Furthermore, inhibition of RIPK1 kinase activity had no effect on IL-1β release. Although IL-1β was released independently of K+ efflux and pyroptosis, it was significantly reduced by an inhibitor of GSDMD. Therefore, it is feasible that low level GSDMD pore formation may facilitate the release of IL-1β from the cell, but not be present in sufficient quantities to initiate pyroptosis. Together these data suggest that the alternative pathway operates independently of RIPK1 kinase activity, downstream of diverse TLRs including TLR4 in primary human monocytes and supports the potential for IL-1β release via GSDMD pores alongside other unconventional secretory pathways. [ABSTRACT FROM AUTHOR]

The immune system of multicellular organisms protects them from harmful microbes. To establish an infection in the face of host immune responses, pathogens must evolve specific strategies to target immune defense mechanisms. One such defense is the formation of intracellular protein complexes, termed inflammasomes, that are triggered by the detection of microbial components and the disruption of homeostatic processes that occur during bacterial infection. Formation of active inflammasomes initiates programmed cell death pathways via activation of inflammatory caspases and cleavage of target proteins. Inflammasome-activated cell death pathways such as pyroptosis lead to proinflammatory responses that protect the host. Bacterial infection has the capacity to influence inflammasomes in two distinct ways: activation and perturbation. In this review, we discuss how bacterial activities influence inflammasomes, and we discuss the consequences of inflammasome activation or evasion for both the host and pathogen. [ABSTRACT FROM AUTHOR]

Apoptosis is defined as programmed cell death, which regulates cellular functions and various physiological responses. Several studies reported that Caspase genes play important roles in the apoptosis and inflammation process. Caspase-8 (CASP8) is a member of the cysteine protease family and a key regulator gene in the induction of apoptosis. In present study, we aimed to investigate the possible associations between the CASP8; D302H (G>C) gene polymorphism and colorectal cancer risk and prognosis.

Abstract Mechanisms underlying the negative effects of obesity on the brain are still unknown. Obesity is associated with oxidative stress in the brain and neuroinflammation that promotes neurodegenerative diseases. Chronic low‐grade neuroinflammation in obesity could be associated with lower volumes of gray matter and lower neuronal density. If neuroinflammation mediated by the expression of cytokines and chemokines leads to apoptosis, this can be assessed by examining caspase expression. The aim of this study was to compare the expression of caspases in the 16 brains of donors with obesity/overweight (n = 8; Body Mass Index [BMI] = 31.6 ± 4.35 kg/m2; 2 females; Age = 52.9 ± 4.76 years) and normal weight (n = 8; BMI = 21.8 ± 1.5 kg/m2; 3 females; Age = 37.8 ± 19.2 years). Sixteen human brain samples were processed. Serial paraffin sections were examined by anti‐caspase immunochemistry (caspase‐3, caspase‐4, caspase‐6, caspase‐1, caspase‐8, and caspase‐9 antibodies). Postmortem samples of cerebral cortex tissue were captured as photomicrographs and the images obtained were analyzed using ImageJ software to obtain the percentage of positive caspase expression. Nonparametric Mann–Whitney U tests were performed to compare caspase expression between samples from donors with obesity/overweight and normal weight. Taking into consideration the immunohistochemistry results, the Search Tool for the Retrieval of Interacting Genes was used to model molecular interactions. Results showed that brain samples from individuals with obesity/overweight exhibited significantly greater values of positive expression for Caspase‐1 (U = 16.5, p = 0.05, Cohen d = 0.89) and −8 (U = 15, p = 0.03, Cohen d = 0.99) than those from donors with normal weight. This study contributes to the knowledge about the inflammatory effects of obesity/overweight on brain, suggesting the activation of the alternative inflammasome pathway in which interact caspase‐1 and ‐8.

Breast cancer is the second leading contributor to the age-standardized mortality rate, for both sexes and all ages worldwide. In Europe and the United States, it is the second leading cause of mortality, with an incidence rate of about 2.6 million cases per year. Noscapine, a well-known alkaloid used as a cough suppressant, demonstrated anti-tumor effects by triggering apoptosis in various cancer cell lines and has the potential to become another ally against breast, ovarian, colon, and gastric cancer, among other types of malignancy. Apoptosis plays a crucial role in the treatment of cancer. Noscapine affected BAX, CASP8, CASP9, NFKBIA, and RELA gene and protein expression in the MCF-7 and MDA-MB-231 cell lines. Gene expression was higher in tumor than in normal tissue, including the BAX expression levels in lung, ovary, endometrium, colon, stomach, and glioblastoma patients; BCL2L1 expression in endometrium, colon, and stomach patients; CASP8 gene expression levels in lung, endometrium, colon, stomach, and glioblastoma patients; RELA in colon, stomach, and glioblastoma patients; and NFKBIA in glioblastoma patients. It can be concluded that noscapine affected genes and proteins related to apoptosis in cancer cell lines and several types of cancer patients.

The potential health benefits of phytochemicals in preventing and treating diseases have gained increasing attention. Here, we proved that the methylated isoflavone prunetin possesses a reno-therapeutic effect against renal ischemia/reperfusion (I/R) insult by activating G protein-coupled receptor 30 (GPR30). After choosing the therapeutic dose of prunetin against renal I/R injury in the pilot study, male Sprague Dawley rats were allocated into 5 groups; viz., sham-operated (SO), SO injected with 1 mg/kg prunetin intraperitoneally for three successive days, untreated I/R, I/R treated with prunetin, and I/R treated with G-15, the selective GPR30 blocker, followed by prunetin. Treatment with prunetin reversed the I/R renal injury effect and majorly restored normal renal function and architecture. Mechanistically, prunetin restored the I/R-induced depletion of renal GPR30, an impact that was canceled by the pre-administration of G-15. Additionally, post-administration of prunetin normalized the boosted inflammatory markers indoxyl sulfate, TLR4, and TRIF and abrogated renal cell demise by suppressing necroptotic signaling, verified by the inactivation of p-RIPK1, p-RIPK3, and p-MLKL while normalizing the inhibited caspase-8. Besides, prunetin reversed the I/R-mediated mitochondrial fission by inhibiting the protein expression of PGMA5 and p-DRP-1. All these favorable impacts of prunetin were nullified by G-15. To sum up, prunetin exhibited a significant reno-therapeutic effect evidenced by the enhancement of renal morphology and function, the suppression of the inflammatory cascade indoxyl sulfate/TLR4/TRIF, which turns off the activated/phosphorylated necroptotic trajectory RIPK1/RIPK3/MLKL, while enhancing caspase-8. Additionally, prunetin opposed the mitochondrial fission pathway RIPK3/PGMA5/DRP-1, effects that are mediated via the activation of GPR30.

The canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) pathway involves a priming step to induce pro-IL-1β followed by a secondary signal such as K+ efflux to activate inflammasome formation. This then leads to the maturation of IL-1β and the formation of gasdermin D (GSDMD) pores that initiate pyroptosis and mediate IL-1β release. In contrast, primary human monocytes also engage an alternative pathway in response to toll-like receptor (TLR) 4 activation, without the need for a secondary signal. Data from a monocyte-like cell line suggest that the alternative pathway functions via the TLR adaptor protein TIR-domain-containing adapter-inducing interferon-β (TRIF), receptor-interacting protein kinase 1 (RIPK1), FAS-associated death domain (FADD) and caspase-8 upstream of NLRP3 activation, but in the absence of K+ efflux or pyroptosis. Usage of the alternative pathway by other members of the TLR family that induce IL-1β but do not signal through TRIF, has yet to be explored in primary human monocytes. Furthermore, the mechanism by which IL-1β is released from monocytes remains unclear. Therefore, this study investigated if the alternative NLRP3 inflammasome pathway is initiated following activation of TLRs other than TLR4, and if GSDMD was necessary for the release of IL-1β. Monocytes were stimulated with ligands that activate TLR1/2, TLR2/6, TLR4 and TLR7 and/or TLR8 (using a dual ligand). Similar to TLR4, all of the TLRs investigated induced IL-1β release in a NLRP3 and caspase-1 dependent manner, indicating that TRIF may not be an essential upstream component of the alternative pathway. Furthermore, inhibition of RIPK1 kinase activity had no effect on IL-1β release. Although IL-1β was released independently of K+ efflux and pyroptosis, it was significantly reduced by an inhibitor of GSDMD. Therefore, it is feasible that low level GSDMD pore formation may facilitate the release of IL-1β from the cell, but not be present in sufficient quantities to initiate pyroptosis. Together these data suggest that the alternative pathway operates independently of RIPK1 kinase activity, downstream of diverse TLRs including TLR4 in primary human monocytes and supports the potential for IL-1β release via GSDMD pores alongside other unconventional secretory pathways.

Background and Objectives: Natural products have proven to be a valuable source for the discovery of new candidate drugs for cancer treatment. This study aims to investigate the potential therapeutic effects of "Kerra™", a natural extract derived from a mixture of nine medicinal plants mentioned in the ancient Thai scripture named the Takxila Scripture, on HCT116 cells. Materials and Methods: In this study, the effect of the Kerra™ extract on cancer cells was assessed through cell viability assays. Apoptotic activity was evaluated by examining the apoptosis characteristic features. A proteomics analysis was conducted to identify proteins and pathways associated with the extract's mechanism of action. The expression levels of apoptotic protein markers were measured to validate the extract's efficacy. Results: The Kerra™ extract demonstrated a dose-dependent inhibitory effect on the cells, with higher concentrations leading to decreased cell viability. Treatment with the extract for 72 h induced characteristic features of early and late apoptosis, as well as cell death. An LC-MS/MS analysis identified a total of 3406 proteins. The pathway analysis revealed that the Kerra™ extract stimulated apoptosis and cell death in colorectal cancer cell lines and suppressed cell proliferation in adenocarcinoma cell lines through the EIF2 signaling pathway. Upstream regulatory proteins, including cyclin-dependent kinase inhibitor 1A (CDKN1A) and MYC proto-oncogene, bHLH transcription factor (MYC), were identified. The expressions of caspase-8 and caspase-9 were significantly elevated by the Kerra™ extract compared to the chemotherapy drug Doxorubicin (Dox). Conclusions: These findings provide strong evidence for the ability of the Kerra™ extract to induce apoptosis in HCT116 colon cancer cells. The extract's efficacy was demonstrated by its dose-dependent inhibitory effect, induction of apoptotic activity, and modulation of key proteins involved in cell death and proliferation pathways. This study highlights the potential of Kerra™ as a promising therapeutic agent in cancer treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Caspase-8 is a protease mediating the activation of the extrinsic apoptotic process that leads to programmed cellular death. Evasion of apoptosis is one of the key hallmarks of cancer and Caspase-8 has commonly been associated with an antitumor protective role. However, observations that several solid tumor types inconsistently display aberrantly high levels of Caspase-8 has fueled studies that challenge this dogma. In this review, we summarize the current state of the art on how tumors benefit from high levels of Caspase-8 expression. In addition, we discuss the mechanisms through which tumors are able to alter the function of Caspase-8 and turn a protective protein into an ally. Specifically, we focus on the role played by tyrosine kinases in inhibiting the enzymatic role of Caspase-8 and remodulating Caspase-8 function in cancer through tyrosine phosphorylation. Caspase-8 is a cysteine-aspartic acid protease that has been identified as an initiator caspase that plays an essential role in the extrinsic apoptotic pathway. Evasion of apoptosis is a hallmark of cancer and Caspase-8 expression is silenced in some tumors, consistent with its central role in apoptosis. However, in the past years, several studies reported an increased expression of Caspase-8 levels in many tumors and consistently identified novel "non-canonical" non-apoptotic functions of Caspase-8 that overall promote cancer progression and sustain therapy resistance. These reports point to the ability of cancer cells to rewire Caspase-8 function in cancer and raise the question of which are the signaling pathways aberrantly activated in cancer that may contribute to the hijack of Caspase-8 activity. In this regard, tyrosine kinases are among the first oncogenes ever identified and genomic, transcriptomic and proteomic studies indeed show that they represent a class of signaling molecules constitutively activated in most of the tumors. Here, we aim to review and discuss the role of Caspase-8 in cancer and its interplay with Src and other tyrosine kinases. [ABSTRACT FROM AUTHOR]

This research aimed to investigate the synergistic protective effect of exercise training and taurine on Akt–Foxo3a–Caspase-8 signaling related to infarct size and cardiac dysfunction. Therefore, 25 male Wistar rats with MI were divided into five groups: sham (Sh), control-MI(C-MI), exercise training-MI(Exe-MI), taurine supplementation-MI(Supp-MI), and exercise training + taurine-MI(Exe + Supp-MI). The taurine groups were given a 200 mg/kg/day dose of taurine by drinking water. Exercise training was conducted for 8 weeks (5 days/week), each session alternated 2 min with 25–30% VO2peak and 4 min with 55–60% VO2peak for 10 alternations. Then, the left ventricle tissue samples were taken from all groups. Exercise training and taurine activated Akt and decreased Foxo3a. Expression of the caspase-8 gene was increased in cardiac necrosis after MI, While, after 12 weeks of intervention decreased. Results exhibited that exercise training combined with taurine has a greater effect than either alone on activating the Akt–Foxo3a–caspase signaling pathway (P < 0.001). MI-induced myocardial injury leads to increase collagen deposition (P < 0.001) and infarct size and results in cardiac dysfunction via reduced stroke volume, ejection fraction, and fractional shortening (P < 0.001). Exercise training and taurine improved cardiac functional parameters (SV, EF, FS) and infarct size (P < 0.001) after 8 weeks of intervention in rats with MI. Also, the interaction of exercise training and taurine has a greater effect than alone on these variables. Interaction of exercise training with taurine supplementation induces a general amelioration of the cardiac histopathological profiles and improves cardiac remodeling via activating Akt–Foxo3a–Caspase-8 signaling with protective effects against MI. [ABSTRACT FROM AUTHOR]

Pulsed Electromagnetic Field (PEMF) is a low-frequency electromagnetic field that has gained popularity in clinical research in recent years for its potential therapeutic benefits. Unlike studies evaluating the effects of PEMF exposure combined with chemotherapeutic drugs at different frequencies, intensities, wavelengths and durations on apoptosis in various cancer cells, including brain cancer cells, in the study, the possible effects of long-term (48 hours) PEMF exposure at constant frequency and intensity (50 Hz, 1 mT) on the apoptosis mechanism in human neuroblastoma cells have been investigated by different techniques. Cells group is divided into three experimental groups as control, SK-N-SH cell group without PEMF exposure, and SK-N-SH cell group exposed to PEMF for 48 hours. Alamar blue, flow cytometry, qRT-PCR and Western-Blotting techniques were utilized to measure cell viability, apoptosis, mRNA level and protein expression of the caspase-8. It has been shown that longterm PEMF exposure significantly reduces cell viability in human neuroblastoma cells, inducing the cells to a significant amount of early apoptosis, and this mechanism may be explained by the increased mRNA and protein expression level of the caspase-8. [ABSTRACT FROM AUTHOR]

Abstract Background Caspase-8 (Casp8) acts as an initiator in cell apoptosis signaling. However, the role of Casp8 in tuning the tumor immune microenvironment remains controversial due to the complicated crosstalk between immune-tolerogenic apoptotic cell death and immunogenic cell death cascades. Methods The Cancer Genome Atlas (TCGA) and publicly accessible immune checkpoint blockade (ICB)-treated cohorts were used to investigate the clinical relevance of Casp8. A tumor-bearing mouse model was used to characterize changes in the tumor microenvironment and to explore the efficacy of ICB treatment under Casp8 knockout conditions. Results By exploring TCGA datasets, we showed that the expression level of Casp8 was associated with an immuno-hot microenvironment across various solid tumor types. Casp8 deficiency leads to decreased CD8+ T cell infiltration and resistance to anti-PD-L1 therapy in a mouse model. Mechanistically, Casp8 deficiency or pharmacological disruption results in impaired ecto-calreticulin transition in tumor cells, which in turn hampers antigen presentation in draining lymph nodes. Furthermore, radiotherapy restored sensitivity to anti-PD-L1 treatment via elevated calreticulin surface expression. Conclusions Our data revealed a causative role of Casp8 in modulating the immunogenicity of tumor cells and responsiveness to ICB immunotherapies and proposed radiotherapy as a salvage approach to overcome Casp8 deficiency-mediated ICB resistance.

Abstract Background Kawasaki disease (KD) is a kind of vasculitis with unidentified etiology. Given that the current diagnosis and therapeutic strategy of KD are mainly dependent on clinical experiences, further research to explore its pathological mechanisms is warranted. Methods Enzyme linked immunosorbent assay (ELISA) was used to measure the serum levels of SIGIRR, TLR4 and caspase-8. Western blotting was applied to determine protein levels, and flow cytometry was utilized to analyze cell apoptosis. Hematoxylin eosin (HE) staining and TUNEL staining were respectively used to observe coronary artery inflammation and DNA fragmentation. Results In this study, we found the level of SIGIRR was downregulated in KD serum and KD serum-treated endothelial cells. However, the level of caspase-8 was increased in serum from KD patients compared with healthy control (HC). Therefore, we hypothesized that SIGIRR-caspase-8 signaling may play an essential role in KD pathophysiology. In vitro experiments demonstrated that endothelial cell apoptosis in the setting of KD was associated with caspase-8 activation, and SIGIRR overexpression alleviated endothelial cell apoptosis via inhibiting caspase-8 activation. These findings were also recapitulated in the Candida albicans cell wall extracts (CAWS)-induced KD mouse model. Conclusion Our data suggest that endothelial cell apoptosis mediated by SIGIRR-caspase-8 signaling plays a crucial role in coronary endothelial damage, providing potential targets to treat KD.

Objective: Although our previous genome-wide association study (GWAS) has identified chromosome 2q33.1 as a susceptibility locus for non-small cell lung cancer (NSCLC), the causal variants remain unclear. The aims of this study were to identify the causal variants in 2q33.1 and to explore their biological functions in NSCLC. Methods: CCK-8, colony formation, EdU incorporation, Transwell, and quantitative real-time polymerase chain reaction assays were applied to examine variant function. The tumor xenograft model was used to examine variant function in vivo. Caspase-8 activity assays, flow cytometry analysis, and co-immunoprecipitation assays were used to explore the molecular mechanism. Results: The missense variant rs3769823 (A > G), which caused the substitution of lysine with arginine at amino acid 14 in caspase-8 (caspase-8K14R), was identified as a potential causal candidate in 2q33.1. Compared with the wild type caspase-8 (caspase-8WT) group, the caspase-8K14R group had higher expression of caspase-8 and cleaved caspase-8. Caspase-8K14R inhibited the proliferation and metastasis of human lung cancer cell lines in vitro. Moreover, caspase-8K14R repressed lung cancer cell growth in vivo. Mechanistically, caspase-8K14R was more sensitive than caspase-8WT to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis and showed higher binding of caspase-8 and FADD. Conclusions: These results suggested that rs3769823 is the causal variant in chromosome 2q33.1 and is involved in an apoptosis pathway, leading to a decreased risk of NSCLC.