Caspase Inhibitor Research Articles

Impaired RelA signaling and lipid metabolism dysregulation in hepatocytes: driving forces in the progression of metabolic dysfunction-associated steatotic liver disease

RelA, also known as nuclear factor kappa B p65, plays a crucial role in the pathogenesis of various liver diseases. However, the specific role of RelA in hepatocytes during the progression of metabolic dysfunction-associated steatotic liver disease (MASLD) is not well understood. This study explored the relationship between impaired RelA signaling and lipid metabolism disorders in hepatocytes, and how they synergistically contribute to the advancement of MASLD. We assessed the changes, regulatory relationships, and impacts of RelA signaling and lipid metabolism remodeling on disease progression both in vitro and in vivo. During MASLD, there was a decrease in the expression of RelA and hepatocyte nuclear factor 1 alpha (HNF1α), with both factors showing mutual enhancement of each other’s expression under normal conditions. This synergistic effect was absent during hepatocyte steatosis. RelA or HNF1α depletion in hepatocytes intensified MASLD symptoms, whereas overexpression of RELA or treatment with necrostatin-1 (a necroptosis inhibitor) or Z-VAD (a caspase inhibitor) significantly mitigated these effects. Mechanistically, during hepatic steatosis, altered lipid profiles exhibited lipotoxicity, inducing hepatocyte apoptosis and necroptosis, whereas endoplasmic reticulum (ER) stress triggered lipid remodeling processes similar to those observed in MASLD. RelA signaling upregulated the expression of activating transcription factor 4 and glucose-regulated protein 78, thereby alleviating ER stress. Impaired RelA signaling remodeled the ER stress response and lipid metabolism, and enhanced lipid accumulation and lipid toxicity. In conclusion, impaired RelA signaling and disrupted lipid metabolism form a detrimental feedback loop in hepatocytes that promotes MASLD progression. Lipid accumulation suppresses RelA signaling, remodeling the ER stress response and exacerbating lipid metabolism disorder, ultimately leading to hepatocyte apoptosis and necroptosis.

Silica Nanoparticles Induce SH-SY5Y Cells Death Via PARP and Caspase Signaling Pathways.

A growing stream of research indicates that exposure to Silica nanoparticles (SiNPs) can cause nervous system damage, leading to the occurrence of neurodegenerative diseases such as Alzheimer's disease. However, the specific mechanism by which SiNPs cause neuroblast injury remains unclear and requires further research. This study established an in vitro experimental model of SH-SY5Y cells exposed to SiNPs and observed cell growth through an inverted fluorescence microscope. Cell viability was measured using an MTT assay. The intracellular ROS and Ca2+ levels were detected by flow cytometry. Cell apoptosis was observed using both Hoechst33342 staining and TUNEL staining. The activities of SOD and ATPase and the content of ATP in the cells were tested by biochemical methods. The genes including parp-1, aif, par, ucp2, vdac and prdx3 were explored using quantitative real-time PCR. The expressions of PARP, AIF, PAR, Caspase-3, Caspase-9 and Cyt C proteins were evaluated by Western Blot. The immunofluorescence technique was used to observe the distribution of Parthanatos-related proteins induced by SiNPs. The results showed that SiNPs reduced cell survival rate, induced excessive ROS and Ca2+ overload, decreased SOD activity, ATPase activity, intracellular and mitochondrial ATP content, increased the expression of mitochondrial function and PARP pathway related genes, as well as PARP and Caspase pathway protein expression, ultimately inducing cell apoptosis. As a further test of the roles of PARP and Caspase pathways in SiNPs induced SH-SY5Y cells death, we selected the PARP inhibitor Olaparib and Caspase inhibitor Z-VAD, and the above effects were significantly improved after treatment with the inhibitors. Conclusively, this study confirmed that SiNPs can generate excessive ROS production in SH-SY5Y cells, alter mitochondrial function, and induce cell death through Parthanatos and caspase dependent apoptotic pathways, which can coexist and interact with each other.

RNase L represses hair follicle regeneration through altered innate immune signaling.

Mammalian injury responses are predominantly characterized by fibrosis and scarring rather than functional regeneration. This limited regenerative capacity in mammals could reflect a loss of pro-regeneration programs or active suppression by genes functioning akin to tumor suppressors. To uncover programs governing regeneration in mammals, we screened transcripts in human subjects following laser rejuvenation treatment and compared them to mice with enhanced Wound Induced Hair Neogenesis (WIHN), a rare example of mammalian organogenesis. We found that Rnasel-/- mice exhibit an increased regenerative capacity, with elevated WIHN through enhanced IL-36α. Consistent with RNase L's known role to stimulate caspase-1, we found that pharmacologic inhibition of caspases promoted regeneration in an IL-36 dependent manner in multiple epithelial tissues. We identified a negative feedback loop, where RNase L activated caspase-1 restrains the pro-regenerative dsRNA-TLR3 signaling cascade through the cleavage of toll-like adaptor protein TRIF. Through integrated single-cell RNA sequencing and spatial transcriptomic profiling, we confirmed Oas & Il36 genes to be highly expressed at the site of wounding and are elevated in Rnasel-/- mice wounds. This work suggests that RNase L functions as a regeneration repressor gene, in a functional tradeoff that tempers immune hyper-activation during viral infection at the cost of inhibiting regeneration.

Licochalcone A Induces Uterine Leiomyoma Cell Apoptosis via the ROS-Mediated JNK Activation of the GRP78/NRF2 Pathway In Vitro and In Vivo

Licochalcone A (LicoA) possesses anti-tumor properties. However, the potential therapeutic effect of LicoA on uterine leiomyomas (ULs) remains unknown. In this study, the effects of LicoA on the proliferation of ULs and its underlying mechanism were explored. LicoA treatment significantly decreased the viability of uterine smooth muscle cells (UtSMCs) and ELT3 cells in a dose-dependent manner. The induction of ELT3 cell apoptosis by LicoA was accompanied by the increased generation of reactive oxygen species (ROS), elevated endoplasmic reticulum (ER) stress (GRP78/IRE1α/ATF6/CHOP), and the increased expression of proapoptotic proteins (c-caspase-3, c-caspase-9, and c-PARP). The ability of Z-VAD-FMK (a caspase inhibitor) and n-acetylcysteine (NAC; a cell membrane permeable antioxidant) to reverse LicoA-induced ROS-mediated ER stress pathways also observed. Furthermore, GRP78 or JNK knockdown was involved in LicoA-induced ROS-mediated ER stress and apoptosis in ELT3 cells. In immunodeficient mice, LicoA significantly suppressed the growth of ELT3 tumor cells, without toxicity. This study is the first to show that LicoA exerts anti-leiomyoma effects via the modulation of ROS-mediated ER stress-induced apoptosis through the JNK/GRP78/NRF2 signaling pathway.

CHMP4C promotes pancreatic cancer progression by inhibiting necroptosis via the RIPK1/RIPK3/MLKL pathway.

Pancreatic cancer (PC) cannot currently be completely cured and has a poor prognosis. Necroptosis is a distinct form of regulated cell death that differs from both necrosis and apoptosis. Understanding the role of necroptosis during PC progression would open new avenues for targeted therapy. The purpose of this study is to examine the impact of necroptosis on the progression of PC and related mechanisms. RNA sequencing was performed to identify necroptosis-related genes that are differentially expressed in PC tissues. The biological functions of CHMP4C and its necroptosis effects were determined in vitro and in vivo. RNA immunoprecipitation, MeRIP-qPCR, Co-immunoprecipitation assays were conducted to evaluate the interaction among CHMP4C, YBX1 and caspase-8 mRNA. Extracellular vesicles were isolated using the differential ultracentrifugation method. The expression of CHMP4C, p-MLKL and CD117 were detected on a PC tissue microarray using multiplex immunofluorescence staining. CHMP4C was significantly overexpressed in PC cells and tissues. It promoted cell growth and suppressed necroptosis of PC cells in both in vivo and in vitro settings. Mechanistically, CHMP4C interacted with YBX1 to mediate m5C modification of caspase-8 mRNA, resulting in increased caspase-8 expression and inhibition of RIPK1/RIPK3/MLKL pathway phosphorylation. Furthermore, CHMP4C promoted extracellular exocytosis of p-MLKL to further suppress necroptosis. Additionally, PC cells used CHMP4C within extracellular vesicles to recruit and stimulate mast cells (MCs), which in turn promoted PC cell proliferation. In PC tissues, the expression of CHMP4C showed a negative correlation with p-MLKL and a positive association with CD117. High expression levels of CHMP4C in patients were associated with poorer overall survival outcomes. CHMP4C promotes PC progression by inhibiting necroptosis, which has potential as a biomarker and therapeutic target in PC.

Transient upregulation of procaspase-3 during oligodendrocyte fate decisions.

Oligodendrocytes are generated throughout life and in neurodegenerative conditions from brain resident oligodendrocyte precursor cells (OPCs). The transition from OPC to oligodendrocyte involves a complex cascade of molecular and morphological states that position the cell to make a fate decision to integrate as a myelinating oligodendrocyte or die through apoptosis. Oligodendrocyte maturation impacts the cell death mechanisms that occur in degenerative conditions, but it is unclear if and how the cell death machinery changes as OPCs transition into oligodendrocytes. Here, we discovered that differentiating oligodendrocytes transiently upregulate the zymogen procaspase-3 in both female and male mice, equipping these cells to make a survival decision during differentiation. Pharmacological inhibition of caspase-3 decreases oligodendrocyte density, indicating that procaspase-3 upregulation is linked to successful oligodendrocyte generation. Moreover, using procaspase-3 as a marker, we show that oligodendrocyte differentiation continues in the aging cortex and white matter. Taken together, our data establish procaspase-3 as a differentiating oligodendrocyte marker and provide insight into the underlying mechanisms occurring during the decision to integrate or die.Significance statement Myelin dysfunction and oligodendrocyte death occur in several neurological disorders and with aging. While new oligodendrocytes can be generated from oligodendrocyte precursor cells throughout life and in neurodegenerative conditions, this process is inefficient with many differentiating oligodendrocytes failing to integrate and dying. Investigating the cellular checkpoints that regulate these fate decisions is complicated by a paucity of molecular markers precisely delineating differentiation stages. Here, we identify that oligodendrocytes transiently upregulate the zymogen procaspase-3 during differentiation, establishing procaspase-3 as a differentiating oligodendrocyte marker. Importantly, procaspase-3 upregulation equips differentiating oligodendrocytes for a fate decision between death or integration and promotes oligodendrocyte differentiation. Thus, our data uncover new insights into mechanisms guiding oligodendrocyte fate decisions.

The SERPINB4 gene mutation identified in twin patients with Crohn’s disease impaires the intestinal epithelial cell functions

Crohn’s disease (CD) is a chronic inflammatory autoimmune disease of unknown etiology. To identify new targets related to the initiation of CD, we screened a pair of twins with CD, which is a rare phenomenon in the Chinese population, for genetic susceptibility factors. Whole-exome sequencing (WES) of these patients revealed a mutation in their SERPINB4 gene. Therefore, we studied a wider clinical cohort of patients with CD or ulcerous colitis (UC), healthy individuals, and those with a family history of CD for this mutation by Sanger sequencing. The single-nucleotide difference in the SERPINB4 gene, which was unique to the twin patients with CD, led to the substitution of lysine by a glutamic acid residue. Functional analysis indicated that this mutation of SERPINB4 inhibited the proliferation, colony formation, wound healing, and migration of intestinal epithelial cells (IECs). Furthermore, mutation of SERPINB4 induced apoptosis and activated apoptosis-related proteins in IECs, and a caspase inhibitor significantly reduced these effects. Transcriptome sequencing revealed that the expression of genes encoding proinflammatory proteins (IL1B, IL6, IL17, IL24, CCL2, and CXCR2) and key proteins in the immune response (S100A9, MMP3, and MYC) was significantly upregulated during SERPINB4 mutant-induced apoptosis. Thus, the heterozygous SERPINB4 gene mutation causes the dysfunction of IECs, which would disrupt the intestinal epithelial barrier and contribute to the development of intestinal inflammation. The activation of SERPINB4 might represent a novel therapeutic target for inflammatory bowel disease.

Role of Caspase 3, Caspase 8 and Caspase 9 in Male Infertility and Sperm Cryoinjury: A Review

Apoptosis is an integral part of sperm development, quality control and differentiation. Caspases are proteolytic enzymes that play a key role in apoptosis. The aim of this review article is to analyze the role of caspases 3, 8 and 9 in male infertility and sperm cryopreservation. The review also discusses the effect of cryopreservation on the activation of caspases in sperm, leading to apoptosis and decreased sperm quality. Finally, the article explores the use of caspase inhibitors as a strategy to improve sperm cryopreservation protocols and preserve sperm quality. Caspase 3 is the dominant effector caspase, while caspase 8 and 9 are involved in the extrinsic and intrinsic apoptotic pathways, respectively. Increased activity of these caspases has been associated with various sperm quality issues, such as teratozoospermia, asthenozoospermia, oligozoospermia and reduced cryostability. The review emphasizes the importance of understanding the role of caspases in sperm apoptosis and their potential as diagnostic markers and therapeutic targets for male infertility and sperm cryopreservation.

Caspase Inhibition Restores Collagen I α1 and Fibronectin Release in Cigarette Smoke Extract-Exposed Human Lung Fibroblasts.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by obstructed airflow, airway remodeling, and inflammation, with cigarette smoke (CS) exposure being the main risk factor. While CS extract (CSE) has been shown to activate caspases in various cell types, the role of caspases in human lung fibroblasts (hLFs), in COPD remains poorly understood. Recent studies have linked caspases to extracellular matrix (ECM) remodeling in skin and kidney fibrosis. Caspase activation can be triggered by oxidative stress, with active caspase-3 executing the pore-forming protein gasdermin E (GSDME) in the cleaved N-terminal form GSDME-NT. We investigated whether CSE activates caspases and GSDME in hLFs, and their role in ECM remodeling. MRC-5 lung fibroblasts were treated with CSE with or without the antioxidant N-acetyl cysteine (NAC), and the caspase-8 inhibitor z-IETD-fmk. We measured the effects on caspase-1-8-3/7 activation, GSDME cleavage, ECM remodeling (procollagen Iα1, COLIα1, and fibronectin, FN), and mitochondrial superoxide (mSOX) generation. Key findings were validated in patient-derived hLFs (phLFs). Our results showed that CSE induced caspase-1-8-3/7 activation, mSOX generation, and decreased COLIα1 and FN levels in MRC-5. CSE caused caspase-8-dependent activation of caspase-3, leading to the GSDME cleavage. Treatment with NAC inhibited mSOX and caspase activation. Inhibition of caspase-8 and mSOX restored FN and COLIα1 levels. In phLFs, we confirmed caspase-1 and -8 activation, mSOX increase, COLIα1/FN decrease, and the effects of NAC. Our findings highlight the role of the axis caspase-8-3/7-GSDME and mSOX in regulating ECM protein, suggesting that these pathways may contribute to remodeling in COPD.

Necroptosis in obesity: a complex cell death event.

Obesity is an exceedingly prevalent and frequent health issue in today's society. Fat deposition is accompanied by low-grade inflammation in fat tissue and throughout the body, leading to metabolic disorders that ultimately promote the onset of obesity-related diseases. The development of obesity is accompanied by cell death events such as apoptosis as well as pyroptosis, however, the role of necroptosis in obesity has been widely reported in recent years. Necroptosis, a mode of cell death distinct from apoptosis and necrosis, is associated with developing many inflammatory conditions and their associated diseases. It also exhibits modulation of apoptosis and pyroptosis. It is morphologically similar to necroptosis, characterized by the inhibition of caspase-8, the formation of membrane pores, and the subsequent rupture of the plasma membrane. This paper focuses on the key pathways and molecules of necroptosis, exploring its connections with apoptosis and pyroptosis, and its implications in obesity. This paper posits that the modulation of necroptosis-related targets may represent a novel potential therapeutic avenue for the prevention and treatment of obesity-induced systemic inflammatory responses, and provides a synopsis of potential molecular targets that may prove beneficial in obesity-associated inflammatory diseases.

Anti-Inflammatory and Anticancer Effects of Kaurenoic Acid in Overcoming Radioresistance in Breast Cancer Radiotherapy.

Background/Objectives: Peroxisome proliferator-activated receptor γ (PPARγ) plays a key role in mediating anti-inflammatory and anticancer effects in the tumor microenvironment. Kaurenoic acid (KA), a diterpene compound isolated from Sphagneticola trilobata (L.) Pruski, has been demonstrated to exert anti-inflammatory, anticancer, and antihuman immunodeficiency virus effects. Methods: In this study, we identified KA as a novel activator of PPARγ with potent anti-inflammatory and antitumor effects both in vitro and in vivo. Given the potential of PPARγ regulators in overcoming radioresistance and chemoresistance in cancer therapies, we hypothesized that KA may enhance the efficacy of breast cancer radiotherapy. Results: In a lipopolysaccharide (LPS)-induced mouse inflammation model, KA treatment reduced the levels of pro-inflammatory cytokines, including COX-2, IL-6, IL-1β, and TNFα. In a xenograft mouse mode of breast cancer, KA treatment inhibited tumor growth. Specifically, KA treatment enhanced caspase-3 activity and cytotoxicity against MDA-MB-231 and MCF-7 breast cancer cells. When KA was co-treated with a caspase inhibitor, Z-VAD-FMK, caspase-dependent apoptosis was suppressed in these cells. KA was found to induce the generation of cytosolic calcium ions (Ca2+) and reactive oxygen species (ROS), triggering endoplasmic reticulum (ER) stress via the PERK-ATF4-CHOP axis. Hence, the ER stressor thapsigargin (TG) synergized with KA treatment to enhance apoptosis in these cells, while the loss of the PERK or CHOP function inhibited this phenomenon. KA treatment was shown to induce oxidative stress via the NADPH oxidase 4 (NOX4) and stimulate ROS production. Specifically, NOX4 knockdown (KD) and antioxidant treatment (N-acetyl cysteine or diphenyleneiodonium) suppressed such ER stress-mediated apoptosis by inhibiting KA-enhanced caspase-3 activity, cytotoxicity, and intracellular ROS production in the treated cells. In radioresistant MDA-MB-231R and MCF-7R cells, KA combined with 2 Gy radiation overcame radioresistance by upregulating PPARγ and modulating epithelial-mesenchymal transition (EMT) markers, such as E-cadherin, N-cadherin, and vimentin. In PPARγ KD MDA-MB-231R and MCF-7R cells, this phenomenon was inhibited due to reduced PPARγ and NOX4 expression. Conclusions: In conclusion, these findings demonstrated KA as a novel PPARγ regulator with promising potential to enhance the efficacy of breast cancer radiotherapy.

A Zeolitic Imidazolate Framework-Based Antimicrobial Peptide Delivery System with Enhanced Anticancer Activity and Low Systemic Toxicity.

The clinical efficacies of anticancer drugs are limited by non-selective toxic effects on healthy tissues and low bioavailability in tumor tissue. Therefore, the development of vehicles that can selectively deliver and release drugs at the tumor site is critical for further improvements in patient survival. We prepared a CEC nano-drug delivery system, CEC@ZIF-8, with a zeolite imidazole framework-8 (ZIF-8) as a carrier, which can achieve the response of folate receptor (FR). We characterized this system in terms of morphology, particle size, zeta potential, infrared (IR), x-ray diffraction (XRD), and transcriptome analysis, and examined the in vitro cytotoxicity and cellular uptake properties of CEC@ZIF-8 using cervical cancer cells. Lastly, we established a TC-1 tumor-bearing mouse model and evaluated its in vivo anti-cervical cancer activity. The CEC@ZIF-8 nano-delivery system had favorable biocompatibility, heat stability, and pH responsiveness, with a CEC loading efficiency of 12%, a hydrated particle size of 174 ± 5.8 nm, a zeta potential of 20.57 mV, and slow and massive drug release in an acidic environment (pH 5.5), whereas release was 6% in a neutral environment (pH 7.4). At the same time, confocal imaging and cell viability assays demonstrated greater intracellular accumulation and more potent cytotoxicity against cancer cells compared to free CEC. The mechanism was analyzed by a series of transcriptome analyses, which revealed that CEC@ZIF-8 NPs differentially regulate the expression levels of 1057 genes in cancer cells, and indicated that the enriched pathways were mainly cell cycle and apoptosis-related pathways via the enrichment analysis of the differential genes. Flow cytometry showed that CEC@ZIF-8 NPs inhibited the growth of HeLa cells by arresting the cell cycle at the G0/G1 phase. Flow cytometry also revealed that CEC@ZIF-8 NPs induced greater apoptosis rates than CEC, while unloaded ZIF-8 had little inherent pro-apoptotic activity. Furthermore, the levels of reactive oxygen species (ROS) were also upregulated by CEC@ZIF-8 NPs while ROS inhibitors and caspase inhibitors reversed CEC@ZIF-8 NPs-induced apoptosis. Finally, CEC@ZIF-8 NPs also reduced the growth rate of xenograft tumors in mice without the systemic toxicity observed with cisplatin treatment. The CEC@ZIF-8 nano-drug delivery system significantly enhanced the anti-cervical cancer effect of CEC both in vivo and in vitro, providing a more promising drug delivery system for clinical applications and tumor management. At the same time, this work demonstrates the clinical potential of CEC-loaded ZIF-8 nanoparticles for the selective destruction of tumor tissues.

Discovery of New Immunomodulatory Anticancer Thalidomide Analogs: Design, Synthesis, Biological Evaluation and In Silico Studies.

New thalidomide analogs have been designed and synthesized by hybridizing the immunomodulatory gutarimide moiety with three antiproliferative nuclei: quinazolinedione, phthalazinedione, and quinoxalinone. The biological results revealed the strong impact of quinazoline derivatives 7 a and 28, and phthalazine based 20 a against HepG-2, MCF-7, PC3, and HCT-116 cell lines, compared to thalidomide. In particular, compound 20 a was the most promising as it had far better biological activity than thalidomide with regard to inhibition of TNF-α, IL-6, caspase 3, COX-I/II, and VEGFR-2, as well as cell cycle arrest, and apoptosis rate enhancement in MCF-7 cells, the most sensitive cell line to the current new molecules. Compound 20 a caused reduction in levels of TNF-α and IL-6 by 75.22 % and 82.51 %, respectively. It elevated the caspase-3 level by 7.21-fold. Furthermore, IC50 against COX-I, COX-II, and VEGFR-2 were 0.65 μM, 0.33 μM, and 232 nM, respectively. In addition, it raised the apoptosis rate from 65.65 % to 99.89 %. Moreover, 20 a was further examined through a docking study and a 200 ns molecular dynamics simulation for its complex with VEGFR-2, along with computational ADME properties. This work suggests the high significance of compounds 20 a, 7 a and 28, as lead compounds for development of new effective immunomodulatory antitumor drugs.

Reduced GATA1 levels are associated with ineffective erythropoiesis in sickle cell anemia.

Ineffective erythropoiesis (IE) is defined as the abnormal differentiation and excessive destruction of erythroblasts in the marrow, accompanied by an expanded progenitor compartment and relative reduction in the production of reticulocytes. It is a defining feature of many types of anemia, including beta-thalassemia. GATA1 is an essential transcription factor for erythroid differentiation, known to be implicated in hematological conditions presenting with IE, including beta-thalassemia and congenital dyserythropoietic anemia. However, little is known about the role of GATA1 in the erythropoietic defects recently described in sickle cell anemia (SCA). In the present study, we performed a detailed characterization of the role of GATA1 and ineffective erythropoiesis in SCA using both invitro and in-vivo assay systems. We demonstrate a significant decrease in GATA1 protein levels during SCA erythropoiesis and a concomitant increase in oxidative stress. Furthermore, we found that an increase in the activity of the inflammatory caspase, caspase 1, was driving the decrease in GATA1 levels during SCA erythropoiesis and that, upon inhibition of caspase 1 activity, SCA erythropoiesis was rescued and GATA1 levels partially restored. Our study further elucidates the defect in erythropoiesis in SCA, and may therefore help in the development of novel approaches to normalise the bone marrow niche prior to stem cell transplantation, or facilitate the production of healthy stem cells for gene therapy.

Wild-Type p53 Regulates Apoptosis of Human Breast Cancer Cells.

The tumor suppressor wild-type p53 is known for its role in inducing apoptosis in tumor cells. This study investigated the relationship between wild-type p53 and protein phosphatase 1 (PP1) and caspase in promoting apoptosis of breast cancer cells. Human breast cancer cell lines MCF-7 and MDA-MB-231 obtained from the American Type Culture Collection were used in this study. Small interference RNAs (Si-RNA) and plasmids were used to regulate wild-type p53 expression in these two tumor cell lines through liposome-mediated transfection. GSK-2830371 (PP1 inhibitor) and zVAD (Caspase inhibitor) were employed to further verify the PP1 activating function of wild-type p53 in Caspase-dependent MCF-7 and MDA-MB-231 apoptosis. PP1 activity was quantitatively detected by phosphorus colorimetric assay. Co-immunoprecipitation (Co-IP), flow cytometry assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, Western blot, the real-time reverse transcriptase-polymerase chain reaction (RT-qPCR), and immunofluorescence staining were used to analyze cell apoptosis degree and marker protein expression. The expression level of PP1 in the breast cancer cells was successfully regulated by cell transfection. The phosphatase activity was increased, and obvious apoptotic cytological characteristics were observed in p53-overexpressed breast cancer cells. p53 knockdown/overexpression increased/decreased the level of B cell lymphoma 2 (Bcl-2), and decreased/increased levels of Caspase-3, cleaved Caspase-3, cleaved Caspase-8, Cytochrome C (Cyt-C), Truncated BID (tBid), Bcl-2-associated X (Bax), and cell apoptosis (p < 0.01). The promotion of proteins and apoptosis induced by p53 overexpression was reversed by GSK-2830371 or zVAD. Wild-type p53 might promote Caspase-dependent apoptosis of human breast cancer cells through PP1 activation.

TRIM7 ubiquitinates SARS-CoV-2 membrane protein to limit apoptosis and viral replication

SARS-CoV-2 is a highly transmissible virus that causes COVID-19 disease. Mechanisms of viral pathogenesis include excessive inflammation and viral-induced cell death, resulting in tissue damage. Here we show that the host E3-ubiquitin ligase TRIM7 acts as an inhibitor of apoptosis and SARS-CoV-2 replication via ubiquitination of the viral membrane (M) protein. Trim7-/- mice exhibit increased pathology and virus titers associated with epithelial apoptosis and dysregulated immune responses. Mechanistically, TRIM7 ubiquitinates M on K14, which protects cells from cell death. Longitudinal SARS-CoV-2 sequence analysis from infected patients reveal that mutations on M-K14 appeared in circulating variants during the pandemic. The relevance of these mutations was tested in a mouse model. A recombinant M-K14/K15R virus shows reduced viral replication, consistent with the role of K15 in virus assembly, and increased levels of apoptosis associated with the loss of ubiquitination on K14. TRIM7 antiviral activity requires caspase-6 inhibition, linking apoptosis with viral replication and pathology.

Ciliopathy interacts with neonatal anesthesia to cause non-apoptotic caspase-mediated motor deficits.

Increasing evidence suggests that anesthesia may induce developmental neurotoxicity, yet the influence of genetic predispositions associated with congenital anomalies on this toxicity remains largely unknown. Children with congenital heart disease often exhibit mutations in cilia-related genes and ciliary dysfunction, requiring sedation for their catheter or surgical interventions during the neonatal period. Here we demonstrate that briefly exposing ciliopathic neonatal mice to ketamine causes motor skill impairments, which are associated with a baseline deficit in neocortical layer V neuron apical spine density and their altered dynamics during motor learning.. These neuromorphological changes were linked to augmented non-apoptotic neuronal caspase activation. Neonatal caspase suppression rescued the spine density and motor deficits, confirming the requirement for sublethal caspase signaling in appropriate spine formation and motor learning. Our findings suggest that ciliopathy interacts with ketamine to induce motor impairments, which is reversible through caspase inhibition. Furthermore, they underscore the potential for ketamine- induced sublethal caspase responses in shaping neurodevelopmental outcomes.

Transient upregulation of procaspase-3 during oligodendrocyte fate decisions.

Oligodendrocytes are generated throughout life and in neurodegenerative conditions from brain resident oligodendrocyte precursor cells (OPCs). The transition from OPC to oligodendrocyte involves a complex cascade of molecular and morphological states that position the cell to make a fate decision to integrate as a myelinating oligodendrocyte or die through apoptosis. Oligodendrocyte maturation impacts the cell death mechanisms that occur in degenerative conditions, but it is unclear if and how the cell death machinery changes as OPCs transition into oligodendrocytes. Here, we discovered that differentiating oligodendrocytes transiently upregulate the zymogen procaspase-3, equipping these cells to make a survival decision during differentiation. Pharmacological inhibition of caspase-3 decreases oligodendrocyte density, indicating that procaspase-3 upregulation promotes differentiation. Moreover, using procaspase-3 as a marker, we show that oligodendrocyte differentiation continues in the aging cortex and white matter. Taken together, our data establish procaspase-3 as a differentiating oligodendrocyte marker and provide insight into the underlying mechanisms occurring during the decision to integrate or die.

The combination of venetoclax and quercetin exerts a cytotoxic effect on acute myeloid leukemia

Venetoclax is a BH3 mimetic that was recently approved for the treatment of acute myeloid leukemia (AML) treatment. However, the effect of venetoclax on AML remains limited, and a novel strategy is required. Here, we demonstrate for the first time that the cytotoxic effect of venetoclax drastically increased when by combined with the naturally occurring flavonoid quercetin. Combined treatment with venetoclax and quercetin caused most of AML KG-1 cells to exhibit a condensed morphology. Cell cycle analysis revealed that the combination strongly induced cell death. Caspase inhibitor blocked this cell death, and the combination induced poly (ADP-ribose) polymerase (PARP) cleavage, indicating that apoptosis was the primary mechanism. These effects were also observed in another AML cell line Kasumi-1 but not in chronic myeloid leukemia (CML) K562 cells. Public data analysis demonstrated that B-cell/CLL lymphoma 2 (Bcl-2) expression is increased in AML cells compared to other malignant tumors, and the survival and the growth of AML cell line depends on Bcl-2. We found that quercetin increased Bcl-2-associated X protein (Bax) expression in KG-1. Our study provides a novel function for quercetin and presents a promising strategy for AML treatment using venetoclax.

Necroptosis as a consequence of photodynamic therapy in tumor cells.

Photodynamic therapy (PDT) is an alternative to cancer treatment, demonstrating selectivity and significant cytotoxicity on malignant tissues. Such therapy involves two nontoxic components: photosensitizer (PS) and non-ionizing radiation. In optimal dosage combinations, PDT causes cellular and tissue effects by oxygen-dependent processes, leading tumor cells to regulated cell death pathways. Regulated necrosis, called necroptosis, can be triggered by PDT and is characterized by caspase-8 inhibition and RIPK1, RIPK3, and MLKL activities, leading to plasma membrane pores formation with subsequent cellular content release into the extracellular space. For this review, studies accessed by PubMed describing the relation between necroptosis and PDT were summarized. The results showed that PDT can trigger necroptosis mechanisms in different tumor cells. Moreover, a mix of different cell death types can co-occur. It is also important to highlight that necroptosis triggered by PDT is related to damage-associated molecular patterns (DAMPs) release, involving immunogenic cell death and vaccination. The cell death response is directly related to the photosensitizer chemical characteristics, concentration, incubation time, cellular location, and irradiation parameters. The synergism among all cell death types is an excellent advantage for avowing tumor resistance mechanisms and developing new solutions.