Death Receptor Pathway Research Articles

Bio-mimetic strategies to re-activate apoptotic cell death for cancer treatments

Apoptosis is a crucial process to maintain the correct balance between healthy cells and committed-to-death cells in every tissue. The internal (or mitochondrial) and external (or death receptor) pathways are responsible for driving a series of molecular events that lead to apoptosis by releasing pro-apoptotic proteins, such as B-cell lymphoma-2 (BCL-2) homology 3 (BH3)-only proteins and second mitochondria-derived activator of caspases/diablo inhibitor of apoptosis protein-binding mitochondrial protein (SMAC/DIABLO), that in turn activate the caspase family of proteases. By counterbalancing the apoptogenic machinery, anti-apoptotic BCL-2 family members turn off pro-apoptotic signalling, favouring cell survival, a circumstance that is particularly pronounced in tumour cells in which apoptosis is deranged. Therefore, targeting the defective apoptotic process has become a viable therapeutic option for the treatment of several cancers and much effort is being made in the research and development of effective compounds. This review discussed and updated the most promising therapeutic strategies that target deranged apoptosis process in cancer by mimicking the pro-apoptotic effects of BH3-only and SMAC/DIABLO proteins.

Reverse hierarchical DED assembly in the cFLIP-procaspase-8 and cFLIP-procaspase-8-FADD complexes

cFLIP, a master anti-apoptotic regulator, targets the FADD-induced DED complexes of procaspase-8 in death receptor and ripoptosome signaling pathways. Several tumor cells maintain relatively high levels of cFLIP in achieving their immortality. However, understanding the three-dimensional regulatory mechanism initiated or mediated by elevated levels of cFLIP has been limited by the absence of the atomic coordinates for cFLIP-induced DED complexes. Here we report the crystal plus cryo-EM structures to uncover an unconventional mechanism where cFLIP and procaspase-8 autonomously form a binary tandem DED complex, independent of FADD. This complex gains the ability to recruit FADD, thereby allosterically modulating cFLIP assembly and partially activating caspase-8 for RIPK1 cleavage. Our structure-guided mutagenesis experiments provide critical insights into these regulatory mechanisms, elucidating the resistance to apoptosis and necroptosis in achieving immortality. Finally, this research offers a unified model for the intricate bidirectional hierarchy-based processes using multiprotein helical assembly to govern cell fate decisions.

Protective effects of dietary protein against nitrite stress in grass carp (Ctenopharyngodon idella): A new perspective

Protein constitutes the predominant essential nutrient in fish feed. Despite extensive research efforts on the dietary protein of fish, limited attention has focused on its potential antistress properties. Therefore, this study sought to examine the impact of dietary protein on the liver structure of grass carp (Ctenopharyngodon idella) and its underlying molecular mechanism after nitrite stress, with the objective of elucidating the role of dietary protein in the stress response of fish. Specifically, various levels of dietary protein (16 %, 19 %, 22 %, 25 %, 28 % and 31 %) were investigated for their effects on liver tissue damage, oxidative stress, endoplasmic reticulum (ER) stress, autophagy and apoptosis in grass carp after exposure to a nitrite solution at a concentration of 10 mg/L for a duration of 96 h.Our study revealed that exposure to nitrite solution resulted in liver structural damage in grass carp. However, 22–25 % dietary protein levels might attenuate the impact of nitrite stress by decreasing liver contents of nitric oxide (NO), peroxynitrite anion (ONOO-), reactive oxygen species (ROS), protein carbonyl (PC), and malondialdehyde (MDA), which is reflected in serum activities of glutamic oxalacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT). Histological analysis further supported the protective role of appropriate protein levels (22–28 %) in alleviating nitrite-induced liver tissue damage. Subsequent investigations demonstrated that optimal dietary protein levels decreased ER stress and autophagy in fish by modulating the expression of gene and protein involved in 78 kDa glucose regulated protein (GRP78) pathway and autophagosome formation process, respectively. Meanwhile, appropriate dietary protein levels decreased the activities of caspase-3, caspase-8 and caspase-9 by inhibiting both death receptor pathway and mitochondrial pathway associated with apoptosis. Finally, based on regression analysis of liver ONOO− content, the dietary protein requirement for grass carp (721–1381 g) under nitrite stress was determined to be 25.07 %. Overall, this study provides novel evidence that optimal protein levels can enhance the resistance of grass carp to nitrite stress and mitigate liver tissue damage by reducing oxidative stress cascade damage.

Fas/FasL-Mediated Apoptosis and Inflammation Contribute to Recovery from HSV-2-Mediated Spinal Cord Infection.

Herpes simplex virus type 2 (HSV-2) is a sexually transmitted pathogen that causes a persistent infection in sensory ganglia. The infection manifests itself as genital herpes but in rare cases it can cause meningitis. In this study, we used a murine model of HSV-2 meningitis to show that Fas and FasL are induced within the CNS upon HSV-2 infection, both on resident microglia and astrocytes and on infiltrating monocytes and lymphocytes. Mice lacking Fas or FasL had a more severe disease development with significantly higher morbidity, mortality, and an overall higher CNS viral load. In parallel, these Fas/FasL-deficient mice showed a severely impaired infection-induced CNS inflammatory response with lower levels of infiltrating CD4+ T-cells, lower levels of Th1 cytokines and chemokines, and a shift in the balance between M1 and M2 microglia/monocytes. In vitro, we confirmed that Fas and FasL is required for the induction of leucocyte apoptosis, but also show that the Fas/FasL pathway is required for adequate cytokine and chemokine production by glial cells. In summary, our data show that the Fas/FasL cell death receptor pathway is an important defense mechanism in the spinal cord as it down-regulates HSV-2-induced inflammation while at the same time promoting adequate anti-viral immune responses against infection.

FSH induces apoptosis in follicular granulosa cells of Tianzhu white yak and regulates the expression of Fas/FasL mRNA.

The Tianzhu white yak, a globally rare species, holds immense value as a source for yak materials. While the Fas/FasL pathway is pivotal in granulosa cells apoptosis, its precise molecular workings remain enigmatic. This study endeavours to decipher the role of follicle-stimulating hormone (FSH) in suppressing ovarian granulosa cells (GC) apoptosis in the Tianzhu white yak. Utilizing advanced cell culture techniques, we employed the MTT method, flow cytometry, fluorescence labelling and RT-PCR to investigate the apoptotic effects of FSH on yak GCs. Our results reveal that FSH's inhibitory effect on GC apoptosis follows a normal distribution pattern, peaking at an FSH concentration of 100 ng/mL with an apoptosis inhibition rate of 89.31%. When serum was withdrawn, an FSH concentration of 2 × 106 ng/mL reduced apoptosis by 72.84%. Annexin V-FITC staining revealed membrane invaginations, bubble and protrusion formation on the cell surface, and alterations in membrane structure and cell morphology. Flow cytometry analysis further demonstrated that FSH administration prior to early granulosa cell apoptosis had a more profound effect than during gradual apoptosis, both showing a suppressive effect on early follicular granulosa cell apoptosis. A transcription-level analysis conducted 3 h prior to serum withdrawal, with the addition of 100 ng/mL FSH, revealed intricate regulations in the expression of Fas/FasL. Notably, we observed a gradual increase in FasL expression over time, yet the presence of FSH effectively down-regulated FasL expression to baseline levels, without notable changes in Fas expression. Immunocytochemical analysis further confirmed the presence of both Fas and FasL on the cell membrane, nucleus and cytoplasm, with varying intensities depending on the duration of FSH treatment. Our findings suggest that FSH may suppress the apoptotic pathway in follicular primarily by down-regulating FasL expression, indicating that Fas-regulated mitochondrial pathways play a more prominent role compared to death receptor pathways. This study offers a fresh perspective on the mechanism underlying follicular atresia in Tianzhu white yaks and lays a solid theoretical foundation for the expansion of this endangered species' population.

Tabersonine Induces the Apoptosis of Human Hepatocellular Carcinoma In vitro and In vivo.

Tabersonine, a natural indole alkaloid derived from Apocynaceae plants, exhibits antiinflammatory and acetylcholinesterase inhibitory activities, among other pharmacological effects. However, its anti-tumor properties and the underlying molecular mechanisms remain underexplored. The present study aims to investigate the anti-tumor effects of tabersonine and its mechanisms in inducing apoptosis in hepatocellular carcinoma. The inhibitory effects of tabersonine on the viability and proliferation of liver cancer cells were evaluated using MTT assay and colony formation assay. AO/EB, Hoechst, and Annexin V-FITC/ PI staining techniques were employed to observe cell damage and apoptosis. JC-1 staining was used to detect changes in mitochondrial membrane potential. Western blot analysis was conducted to study the anti-tumor mechanism of tabersonine on liver cancer cells. Additionally, a xenograft model using mice hepatoma HepG2 cells was established to assess the anti-tumor potency of tabersonine in vivo. Our findings revealed that tabersonine significantly inhibited cell viability and proliferation, inducing apoptosis in liver cancer cells. Treatment with tabersonine inhibited Akt phosphorylation, reduced mitochondrial membrane potential, promoted cytochrome c release from mitochondria to the cytoplasm, and increased the ratio of Bax to Bcl-2. These findings suggested that tabersonine induces apoptosis in liver cancer cells through the mitochondrial pathway. Furthermore, tabersonine treatment activated the death receptor pathway of apoptosis. In vivo studies demonstrated that tabersonine significantly inhibited xenograft tumor growth. Our study is the first to demonstrate that tabersonine induces apoptosis in HepG2 cells through both mitochondrial and death receptor apoptotic pathways, suggesting its potential as a therapeutic agent candidate for hepatic cancer.

Molecular signatures in prion disease: altered death receptor pathways in a mouse model.

Prion diseases are transmissible and fatal neurodegenerative diseases characterized by accumulation of misfolded prion protein isoform (PrPSc), astrocytosis, microgliosis, spongiosis, and neurodegeneration. Elevated levels of cell membrane associated PrPSc protein and inflammatory cytokines hint towards the activation of death receptor (DR) pathway/s in prion diseases. Activation of DRs regulate, either cell survival or apoptosis, autophagy and necroptosis based on the adaptors they interact. Very little is known about the DR pathways activation in prion disease. DR3 and DR5 that are expressed in normal mouse brain were never studied in prion disease, so also their ligands and any DR adaptors. This research gap is notable and investigated in the present study. C57BL/6J mice were infected with Rocky Mountain Laboratory scrapie mouse prion strain. The progression of prion disease was examined by observing morphological and behavioural abnormalities. The levels of PrP isoforms and GFAP were measured as the marker of PrPSc accumulation and astrocytosis respectively using antibody-based techniques that detect proteins on blot and brain section. The levels of DRs, their glycosylation and ectodomain shedding, and associated factors warrant their examination at protein level, hence western blot analysis was employed in this study. Prion-infected mice developed motor deficits and neuropathology like PrPSc accumulation and astrocytosis similar to other prion diseases. Results from this research show higher expression of all DR ligands, TNFR1, Fas and p75NTR but decreased levels DR3 and DR5. The levels of DR adaptor proteins like TRADD and TRAF2 (primarily regulate pro-survival pathways) are reduced. FADD, which primarily regulate cell death, its level remains unchanged. RIPK1, which regulate pro-survival, apoptosis and necroptosis, its expression and proteolysis (inhibits necroptosis but activates apoptosis) are increased. The findings from the present study provide evidence towards the involvement of DR3, DR5, DR6, TL1A, TRAIL, TRADD, TRAF2, FADD and RIPK1 for the first time in prion diseases. The knowledge obtained from this research discuss the possible impacts of these 16 differentially expressed DR factors on our understanding towards the multifaceted neuropathology of prion diseases and towards future explorations into potential targeted therapeutic interventions for prion disease specific neuropathology.

Structural characterization of the polysaccharide from the black crystal region of Inonotus obliquus and its effect on AsPC-1 and SW1990 pancreatic cancer cell apoptosis

In this study, one water soluble polysaccharide (IOP1–1) with a weight average molecular weight of 6886 Da was obtained from the black crystal region of Inonotus obliquus by hot water extraction, DEAE-52 cellulose extraction and Sephadex-100 column chromatography purification. Structural analysis indicated that IOP1–1 was a glucan with a main chain composed of α-Glcp-(1 → 4)-α-Glcp-(1 → 4)-β-Glcp-(1 → 4)-β-Glcp-(1 → 4)-α-Glcp-(1 → 6)-β-Glcp-(1 → 4)-α-Glcp-(1 → 3)-β-Glcp-(1→. The CCK-8 assay results showed that IOP1–1 inhibited AsPC-1 and SW1990 pancreatic cancer cell proliferation in a concentration-dependent manner. Flow cytometric analysis revealed that IOP1–1 induced cell cycle arrest in AsPC-1 and SW1990 cells. Hoechst 33342 staining and Annexin V-FITC/PI double staining analysis showed that IOP1–1 could induce apoptosis in AsPC-1 and SW1990 cells. Furthermore, western blot analysis confirmed that IOP1–1 could induce apoptosis in AsPC-1 and SW1990 pancreatic cancer cells through three pathways: the mitochondrial pathway, the death receptor pathway, and endoplasmic reticulum stress. According to these research data, IOP1–1 may be utilized as an adjuvant treatment to anticancer medications, opening up new application prospects and opportunities.

Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV–visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

A macromolecular Gleditsia Saponin induces apoptosis of leukemia cells through Fas-mediated death receptor pathway and mitochondrial pathway

Gleditsia sinensis Lam., a natural product derived from medicine and food, exhibits outstanding biological activity, with its primary active component being triterpenoid saponin. In this study, a new macromolecular Gleditsia Saponin (GS) with a molecular weight of 27.562 kDa was extracted from Gleditsia sinensis Lam.. The study focused on examining the impact of GS on the suppression of cell growth and the initiation of apoptosis in leukemia K562 and L1210 cells. The results showed that GS notably suppressed the growth of leukemia cells in a manner reliant on concentration. Morphological and Annexin V-FITC/PI staining analyses revealed characteristic features of apoptosis in leukemia cells treated with GS. Moreover, cell cycle analysis indicated that GS effectively arrested leukemia cell progression at the G0/G1 phase. Mitochondrial membrane potential (ΔΨm) was disrupted, and abnormal accumulation of reactive oxygen species was also detected. In addition, GS could induce cell apoptosis through the Fas-mediated death receptor pathway and mitochondrial pathway, leading to the blocking of leukemia cells in the G1 phase. In summary, these results provide theoretical backing and fresh perspectives for the development and utilization of GS as a functional health food.

Effects of Hericium erinaceus polysaccharide in porcine IPEC-J2 intestinal epithelial cells against apoptosis induced by oxidative stress

This study was intended to investigate whether Hericium erinaceus polysaccharides (HEP) prevent oxidative stress and apoptosis of intestinal porcine epithelial cells from jejunum (IPEC-J2 cells) induced by hydrogen peroxide (H2O2). Crude HEP were extracted and purified by chromatography. The ultraviolet and infrared spectra and monosaccharide composition of HEP were analyzed. Reactive oxygen species (ROS) generation was quantified by flow cytometry method, and lactate dehydrogenase (LDH) and malondialdehyde (MDA) production were determined by TBARS. Also, apoptosis was analyzed by flow cytometry method and the apoptosis-related regulatory molecules were determined by microplate or western blotting method. Our results showed that pretreatment of IPEC-J2 cells with HEP significantly scavenged ROS and reduced LDH and MDA production. HEP also reduced apoptosis and kept polarity of the mitochondrial membrane potential. Moreover, HEP increased the content of caspase-3 and PARP, and protein expression of Bcl-2, while inhibited Bax and Bad and reduced the content of caspase-9 and release of CytC. Meanwhile, HEP inhibited the protein expression of TNFR1, FAS, and FASL, and decreased the content of caspase-8. The results indicated that HEP had a protective effect against oxidative stress in IPEC-J2 cells and the underlying mechanism was reducing apoptosis via mitochondrial and death receptor pathways.

Exploring the apoptotic effects of sericin on HCT116 cells through comprehensive nanostring transcriptomics and proteomics analysis

Sericin, a silk protein from Bombyx mori (silkworms), has many applications, including cosmetics, anti-inflammation, and anti-cancer. Sericin complexes with nanoparticles have shown promise for breast cancer cell lines. Apoptosis, a programmed cell death mechanism, stops cancer cell growth. This study found that Sericin urea extract significantly affected HCT116 cell viability (IC50 = 42.00 ± 0.002 µg/mL) and caused apoptosis in over 80% of treated cells. S-FTIR analysis showed significant changes in Sericin-treated cells' macromolecule composition, particularly in the lipid and nucleic acid areas, indicating major cellular modifications. A transcriptomics study found upregulation of the apoptotic signaling genes FASLG, TNFSF10, CASP3, CASP7, CASP8, and CASP10. Early apoptotic proteins also showed that BAD, AKT, CASP9, p53, and CASP8 were significantly upregulated. A proteomics study illuminated Sericin-treated cells' altered protein patterns. Our results show that Sericin activated the extrinsic apoptosis pathway via the caspase cascade (CASP8/10 and CASP3/7) and the death receptor pathway, involving TNFSF10 or FASLG, in HCT116 cells. Upregulation of p53 increases CASP8, which activates CASP3 and causes HCT116 cell death. This multi-omics study illuminates the molecular mechanisms of Sericin-induced apoptosis, sheds light on its potential cancer treatment applications, and helps us understand the complex relationship between silk-derived proteins and cellular processes.

Emerging role of vitamin D3 in alleviating intestinal structure injury caused by Aeromonas hydrophila in grass carp (Ctenopharyngodon idella)

Bacterial pathogens destroy the structural integrity of functional organs in fish, leading to severe challenges in the aquaculture industry. Vitamin D3 (VD3) prevents bacterial infections and strengthens immune system function via vitamin D receptor (VDR). However, the correlation between VD3/VDR and the structural integrity of functional organs remains unclarified. This study aimed to investigate the influence of VD3 supplementation on histological characteristics, apoptosis, and tight junction characteristics in fish intestine during pathogen infection. A total of 540 healthy grass carp (257.24 ± 0.63 g) were fed different levels of VD3 (15.2, 364.3, 782.5, 1,167.9, 1,573.8, and 1,980.1 IU/kg) for 70 d. Subsequently, fish were challenged with Aeromonas hydrophila, a pathogen that causes intestinal inflammation. Our present study demonstrated that optimal supplementation with VD3 (1) alleviated intestinal structural damage, and inhibited oxidative damage by reducing levels of oxidative stress biomarkers; (2) attenuated excessive apoptosis-related death receptor and mitochondrial pathway processes in relation to p38 mitogen-activated protein kinase signaling (P < 0.05); (3) enhanced tight junction protein expression by inhibiting myosin light chain kinase signaling (P < 0.05); and (4) elevated VDR isoform expression in fish intestine (P < 0.05). Overall, the results demonstrated that VD3 alleviates oxidative injury, apoptosis, and the destruction of tight junction protein under pathogenic infection, thereby strengthening pathogen defenses in the intestine. This finding supports the rationale for VD3 intervention as an essential practice in sustainable aquaculture.

Utilizing Chemotherapy to Enhance the Anti-Tumor Properties of Ex Vivo Expanded Gamma Delta (γδ) T Cells Against Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) is the second most common type of blood cancer in children with a high rate of treatment failure and aggressive relapse. While allogeneic HSCT offers a cure, limitations arise in achieving remission prior to transplant. Immunotherapy-based approaches can induce remission, gaining interest in AML. Here, we explore the use of gamma delta (γδ) T cells as a promising tool to fulfill this unmet need. Unlike predominant alpha beta (αβ) T cells, γδ T cells do not require antigen presentation and identify their targets in a major histocompatibility complex (MHC) independent manner. Allogeneic γδ T cells thus have minimal risk of causing graft-versus-host disease (GvHD), creating ‘off-the-shelf’ cellular therapeutics. This would be ideal to target AML, especially given the aggressive nature of relapsed disease. Cytotoxic mechanisms used by γδ T cells include recognition of cellular stress molecules such as NKG2D and DNAM-1 receptor ligands on target cells, activation of death receptor pathway through Fas-FasL and TRAIL-R interactions, as well as γδ ΤCR mediated killing through recognition of butyrophilins (BTNs) on target cells. These stress molecules are expressed on AML cells and can be further upregulated through chemotherapeutic agents such as azacitidine (a hypomethylating agent) and venetoclax (BCL-2 antagonist), drugs currently in use to treat relapsed AML. Here, we tested these drugs in combination with γδ T cells to target AML. Methods Our studies explored four different AML cell lines (Kasumi-1, Nomo-1, MV4-11 and MOLM13). Each one was respectively treated at their corresponding inhibitory concentration 25 (IC 25) and 50 (IC 50) of azacitidine and/or venetoclax for 24 hours. After treatment, AML cells were assessed by flow cytometry for expression of NKG2D and DNAM-1 ligands, death receptor pathway molecules (CD95, TRAIL-R1/R2) as well as the butyrophillins (BTN2A and BTN3A1) to elucidate which pathways are over-expressed, aiding in γδ T cell targeting and cytotoxicity. Next, we co-cultured AML cells pre-treated with azacitidine and/or venetoclax with γδ T cells and measured cytotoxicity using a flow cytometry-based assay and a bioluminescence assay. Results: Each cell line expressed a unique pattern of markers at baseline. Cell lines treated with azacitidine had a robust expression of the NKG2D ligands ULBP1, ULBP2/5/6 and ULBP3. Azacitidine also increased CD155 and TRAIL-R2 in Nomo-1 while CD112 increased in MOLM13. Most venetoclax-treated AML cells over-expressed BTN2A and BTN3A1 along with CD95 in MOLM13. Cell lines were then treated with a combination of both drugs. Dual treatment of cells resulted in a significant increase in expression of most NKG2D markers as well the death receptor Fas (CD95). Additionally, increase in CD155 as well as BTNs was seen in several cell lines. Importantly, azacitidine and venetoclax had minimal effects on the viability of γδ Τ cells when treated for 24 hours. In vitro cytotoxicity studies indicate increased cell death across multiple AML cell lines when γδ T cells were co-cultured with cells pretreated with azacitidine and venetoclax. Conclusions: Azacitidine and venetoclax treatment resulted in upregulation of several markers involved in γδ Τ cell-mediated cytotoxicity. Ex vivo expanded γδ Τ cells combined with chemotherapy-treated AML cells resulted in increased overall cytotoxicity, which is likely both additive and synergistic. Our next steps include preclinical validation of this combinatorial approach in an in-vivo mouse study.

A new insight into fluoride induces cardiotoxicity in chickens: Involving the regulation of PERK/IRE1/ATF6 pathway and heat shock proteins

Fluorosis poses a significant threat to human and animal health and is an urgent public safety concern in various countries. Subchronic exposure to fluoride has the potential to result in pathological damage to the heart, but its potential mechanism requires further investigation. This study investigated the effects of long-term exposure to sodium fluoride (0, 500, 1000, and 2000 mg/kg) on the hearts of chickens were investigated. The results showed that an elevated exposure dose of sodium fluoride led to congested cardiac tissue and disrupted myofiber organisation. Sodium fluoride exposure activated the ERS pathways of PERK, IRE1, and ATF6, increasing HSP60 and HSP70 and decreasing HSP90. The NF-κB pathway and the activation of TNF-α and iNOS elicited an inflammatory response. BAX, cytc, and cleaved-caspase3 were increased, triggering apoptosis and leading to cardiac injury. The abnormal expression of HSP90 and HSP70 affected the stability and function of RIPK1, RIPK3, and MLKL, which are crucial necroptosis markers. HSPs inhibited TNF-α-mediated necroptosis and apoptosis of the death receptor pathway. Sodium fluoride resulted in heart injury in chickens because of the ERS and variations in HSPs, inducing inflammation and apoptosis. Cardiac-adapted HSPs impeded the activation of necroptosis. This paper may provide a reference for examining the potential cardiotoxic effects of sodium fluoride.

Insights into mechanism of DNA damage and repair-apoptosis in digestive gland of female scallop Chlamys farreri under benzo[a]pyrene exposure during reproductive stage

As one of the most carcinogenic persistent organic pollutants (POPs), benzo[a]pyrene (B [a]P) brings high toxicity to marine bivalves. Digestive gland is the most important metabolism-related organ of aquatic animals. This study conducted the digestive gland transcriptome of Chlamys farreri under B[a]P treatment at reproductive stages. And the reproductive-stage dependence metabolism-DNA repair-apoptosis process of scallops under 0, 0.04, 0.4 and 4 μg/L B[a]P was studied by qRT-PCR. The results demonstrated that the detoxification metabolism was disturbed after ovulation except for CYP3A4. In antioxidant system, antioxidant enzyme CAT and GPX, and GGT1 (one of the non-enzymatic antioxidants synthesis gene) continuously served the function of antioxidant defense. Three types of DNA repair were activated under B[a]P stress, however, DNA strand breaks were still serious. B[a]P exposure weakened death receptor pathway as well as enhanced mitochondrial pathway, surprisingly suppressing apoptosis in scallops. In addition, ten indicators were screened by Spearman correlation analysis. This study will provide sound theoretical basis for bivalve toxicology and contribute to the biomonitoring of marine POPs pollution.

Potential pathway and mechanisms underlining the immunotoxicity of benzo[a]pyrene to Chlamys farreri.

The long-distance migration of polycyclic aromatic hydrocarbons (PAHs) promotes their release into the marine environment, posing a serious threat to marine life. Studies have shown that PAHs have significant immunotoxicity effects on bivalves, but the exact mechanism of immunotoxicity remains unclear. This paper aims to investigate the effects of exposure to 0.4, 2, and 10 μg/L of benzo(a)pyrene (B[a]P) on the immunity of Chlamys farreri under environmental conditions, as well as the potential molecular mechanism. Multiple biomarkers, including phagocytosis rate, metabolites, neurotoxicity, oxidative stress, DNA damage, and apoptosis, were adopted to assess these effects. After exposure to 0.4, 2, and 10 μg/L B[a]P, obvious concentration-dependent immunotoxicity was observed, indicated by a decrease in the hemocyte index (total hemocyte count, phagocytosis rate, antibacterial and bacteriolytic activity). Analysis of the detoxification metabolic system in C. farreri revealed that B[a]P produced B[a]P-7,8-diol-9,10-epoxide (BPDE) through metabolism, which led to an increase in the expression of protein tyrosine kinase (PTK). In addition, the increased content of neurotransmitters (including acetylcholine, γ -aminobutyric acid, enkephalin, norepinephrine, dopamine, and serotonin) and related receptors implied that B[a]P might affect immunity through neuroendocrine system. The changes in signal pathway factors involved in immune regulation indicated that B[a]P interfered with Ca2+ and cAMP signal transduction via the BPDE-PTK pathway or neuroendocrine pathway, resulting in immunosuppression. Additionally, B[a]P induced the increase in reactive oxygen species (ROS) content and DNA damage, as well as an upregulation of key genes in the mitochondrial pathway and death receptor pathway, leading to the increase of apoptosis rate. Taken together, this study comprehensively investigated the detoxification metabolic system, neuroendocrine system, and cell apoptosis to explore the toxic mechanism of bivalves under B[a]P stress.

Therapeutic Potential of Plant Metabolites in Bone Apoptosis: A Review.

Osteoporosis is one of the skeletal diseases of major health concern worldwide. Homeostasis of bone occurs with the help of cells, namely, osteoblasts and osteoclasts. Physiological and pathological conditions involve the death of the cells by apoptosis, autophagy, and necrosis. Apoptosis is a key factor in the growth, development, and maintenance of the skeleton. Apoptosis is generated by two pathways: the intrinsic (mitochondria) and extrinsic (death receptor) pathways. Osteoblast apoptosis is governed by the factors like B cell lymphoma 2 (Bcl-2) family proteins, extracellular signal-regulated kinase (ERK), mitogen-activated protein kinases (MAPK), phosphoinositide-3-kinase/ protein kinase B (PI3-K/Akt), Janus kinase 2 (JAK2), bone morphogenetic protein (BMP), and bone matrix protein. Cytokines interact with osteocytes and induce apoptosis. A pro-inflammatory signal stimulates osteocyte apoptosis and increases osteocyte cytokines production. Current therapies have adverse effects which limit their applications. Various plant metabolites have shown beneficial effects on bone. The present review converses about normal bone metabolism and the mechanism of apoptosis leading to bone deterioration. Furthermore, it discusses the role of plant metabolites on bone apoptosis with related indications of efficacy in various experimental models.

Cinobufagin: a promising therapeutic agent for cancer.

Cinobufagin is a natural active ingredient isolated from the traditional Chinese medicine Venenum Bufonis (Chinese: Chansu), which is the dried secretion of the postauricular gland or skin gland of the Bufo gargarizans Cantor or Bufo melanostictus Schneider. There is increasing evidence indicating that cinobufagin plays an important role in the treatment of cancer. This article is to review and discuss the antitumor pharmacological effects and mechanisms of cinobufagin, along with a description of its toxicity and pharmacokinetics. The public databases including PubMed, China National Knowledge Infrastructure and Elsevier were referenced, and 'cinobufagin', 'Chansu', 'Venenum Bufonis', 'anticancer', 'cancer', 'carcinoma', and 'apoptosis' were used as keywords to summarize the comprehensive research and applications of cinobufagin published up to date. Cinobufagin can induce tumour cell apoptosis and cycle arrest, inhibit tumour cell proliferation, migration, invasion and autophagy, reduce angiogenesis and reverse tumour cell multidrug resistance, through triggering DNA damage and activating the mitochondrial pathway and the death receptor pathway. Cinobufagin has the potential to be further developed as a new drug against cancer.

Methanol extracts of Undaria pinnatifida induces apoptosis via the death-receptor and Bcl-2 family pathway in human oral cancer cells

Methanol extracts of <i>Undaria pinnatifida</i> induces apoptosis via the death-receptor and Bcl-2 family pathway in human oral cancer cells