Necroptosis in development, inflammation and disease

An acidic pH environment converts necroptosis to apoptosis

Cardiac ischemia results in anaerobic metabolism and lactic acid accumulation and with time, intracellular and extracellular acidosis. Ischemia and subsequent reperfusion injury (IRI) lead to various forms of programmed cell death. Necroptosis is a major form of programmed necrosis that worsens cardiac function directly and also promotes inflammation by the release of cellular contents. Potential effects of increasing acidosis on programmed cell death and their specific components have not been well studied. While apoptosis is caspase-dependent, in contrast, necroptosis is mediated by the receptor-interacting protein kinases 1 and 3 (RIPK1/3). In our study, we observed that at physiological pH = 7.4, caspase-8 inhibition did not prevent TNFα-induced cell death in mouse cardiac vascular endothelial cells (MVECs) but promoted necroptotic cell death. As expected, necroptosis was blocked by RIPK1 inhibition. However, at pH = 6.5, TNFα induced an apoptosis-like pattern which was inhibited by caspase-8 inhibition. Interestingly phosphorylation of necroptotic molecules RIPK1, RIPK3, and mixed lineage kinase domain-like protein (MLKL) was enhanced in an acidic pH environment. However, RIPK3 and MLKL phosphorylation was self-limited which may have limited their participation in necroptosis. In addition, an acidic pH promoted apoptosis-inducing factor (AIF) cleavage and nuclear translocation. AIF RNA silencing inhibited cell death, supporting the role of AIF in this cell death. In summary, our study demonstrated that the pH of the micro-environment during inflammation can bias cell death pathways by altering the function of necroptosis-related molecules and promoting AIF-mediated cell death. Further insights into the mechanisms by which an acidic cellular micro-environment influences these and perhaps other forms of regulated cell death, may lead to therapeutic strategies to attenuate IRI.

Autophagy-lysosomal-associated neuronal death in neurodegenerative disease

Autophagy, the major lysosomal pathway for degrading damaged or obsolete constituents, protects neurons by eliminating toxic organelles and peptides, restoring nutrient and energy homeostasis, and inhibiting apoptosis. These functions are especially vital in neurons, which are postmitotic and must survive for many decades while confronting mounting challenges of cell aging. Autophagy failure, especially related to the declining lysosomal ("phagy") functions, heightens the neuron's vulnerability to genetic and environmental factors underlying Alzheimer's disease (AD) and other late-age onset neurodegenerative diseases. Components of the global autophagy-lysosomal pathway and the closely integrated endolysosomal system are increasingly implicated as primary targets of these disorders. In AD, an imbalance between heightened autophagy induction and diminished lysosomal function in highly vulnerable pyramidal neuron populations yields an intracellular lysosomal build-up of undegraded substrates, including APP-βCTF, an inhibitor of lysosomal acidification, and membrane-damaging Aβ peptide. In the most compromised of these neurons, β-amyloid accumulates intraneuronally in plaque-like aggregates that become extracellular senile plaques when these neurons die, reflecting an "inside-out" origin of amyloid plaques seen in human AD brain and in mouse models of AD pathology. In this review, the author describes the importance of lysosomal-dependent neuronal cell death in AD associated with uniquely extreme autophagy pathology (PANTHOS) which is described as triggered by lysosomal membrane permeability during the earliest "intraneuronal" stage of AD. Effectors of other cell death cascades, notably calcium-activated calpains and protein kinases, contribute to lysosomal injury that induces leakage of cathepsins and activation of additional death cascades. Subsequent events in AD, such as microglial invasion and neuroinflammation, induce further cytotoxicity. In major neurodegenerative disease models, neuronal death and ensuing neuropathologies are substantially remediable by reversing underlying primary lysosomal deficits, thus implicating lysosomal failure and autophagy dysfunction as primary triggers of lysosomal-dependent cell death and AD pathogenesis and as promising therapeutic targets.

Preclinical Evaluation of Dihydropyrazole-Cored Positron Emission Tomography (PET) Ligands for Imaging of Receptor-Interacting Serine/Threonine Protein Kinase 1 (RIPK1) in the Brain

Receptor-interacting serine/threonine protein kinase 1 (RIPK1) has emerged as an important regulator of pathologic cell death and inflammation and is implicated in the pathologies of various central nervous system diseases. In this study, we reported the development of three potent dihydropyrazole-cored RIPK1 positron emission tomography (PET) ligands [18F]WL1-3. Among these, [18F]WL1 showed specific binding to RIPK1 in mouse brain sections in vitro through autoradiography and exhibited favorable brain kinetics in mice, characterized by a high initial uptake (brain2 min = 4.89% ID/g) and rapid washout (brain60 min = 0.21% ID/g). PET studies in rat brains revealed that [18F]WL1 could readily penetrate the brain with specific binding confirmed by inhibition effects of unlabeled WL1 and GSK'547. Notably, [18F]WL1 showed significant potential in imaging the alterations of RIPK1 in a rat brain of tumor necrosis factor α-induced systemic inflammatory response syndrome model. These findings may pave the way for the future design of potent RIPK1 PET ligands.

Targeting cell death in NAFLD: mechanisms and targeted therapies

Nonalcoholic fatty liver disease (NAFLD) is a group of chronic liver disease which ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) and is characterized by lipid accumulation, inflammation activation, fibrosis, and cell death. To date, a number of preclinical studies or clinical trials associated with therapies targeting fatty acid metabolism, inflammatory factors and liver fibrosis are performed to develop effective drugs for NAFLD/NASH. However, few therapies are cell death signaling-targeted even though the various cell death modes are present throughout the progression of NAFLD/NASH. Here we summarize the four types of cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis in the NAFLD and the underlying molecular mechanisms by which the pathogenic factors such as free fatty acid and LPS induce cell death in the pathogenesis of NAFLD. In addition, we also review the effects of cell death-targeted therapies on NAFLD. In summary, our review provides comprehensive insight into the roles of various cell death modes in the progression of NAFLD, which we hope will open new avenues for therapeutic intervention.

Structure-based discovery of a 4,5-Dihydropyrazole-cored PET ligand for imaging of receptor-interacting serine/threonine-protein kinase 1 (RIPK1) in the brain

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) regulates programmed cell death and inflammation, contributing to a wide range of human pathologies, including inflammatory disorders, neurodegenerative conditions, and cancer. Despite this, no RIPK1 positron emission tomography (PET) ligand with significant in vivo specificity has been reported to date. In this work, we designed and synthesized a new family of dihydropyrazole-cored ligands suitable for 18F-labeling at the late stage. Among these, WL8 showed a strong binding affinity to RIPK1 (EC50 = 19.9 nM, Kd = 25 nM) and was successfully labeled with 18F in the 6-position of pyridine ring, yielding a high radiochemistry yield of 27.9 % (decay-corrected) and a high molar activity of 18.8-31.2 GBq/μmol. In in vitro autoradiography, [18F]WL8 showed some specific binding in the brain sections of rats and lipopolysaccharide (LPS) model mice. Preliminary PET studies in rat brains revealed that [18F]WL8 could efficiently penetrate the blood-brain barrier and was rapidly washed out. As anticipated, [18F]WL8 exhibited a high initial uptake (brain2min = 4.80 % ID/g) in mouse brains, followed by a rapid washout (brain60min = 0.14 % ID/g), although no clear specific binding to RIPK1 was observed. Moderate in vivo stability was noted for [18F]WL8 in mouse brains with 35.2 % of the parent fraction remaining after 30 min post-administration. Altogether, our work broadens the landscape and offers a new chemotype for RIPK1 PET ligand development.

Mitochondrial calcium uniporter complex: Unveiling the interplay between its regulators and calcium homeostasis

The mitochondrial calcium uniporter complex (MCUc), serving as the specific channel for calcium influx into the mitochondrial matrix, is integral to calcium homeostasis and cellular integrity. Given its importance, ongoing research spans various disease models to understand the properties of the MCUc in pathophysiological contexts, but reported a different conclusion. Therefore, this review delves into the profound connection between MCUc-mediated calcium transients and cellular signaling pathways, mitochondrial dynamics, metabolism, and cell death. Additionally, we shed light on the recent advancements concerning the structural intricacies and auxiliary components of the MCUc in both resting and activated states. Furthermore, emphasis is placed on novel extrinsic and intrinsic regulators of the MCUc and their therapeutic implications across a spectrum of diseases. Meanwhile, we employed molecular docking simulations and identified candidate traditional Chinese medicine components with potential binding sites to the MCUc, potentially offering insights for further research on MCUc modulation.

Role of angiotensin converting enzyme in pathogenesis associated with immunity in cardiovascular diseases

Angiotensin converting enzyme (ACE) is not only a critical component in the renin-angiotensin system (RAS), but also suggested as an important mediator for immune response and activity, such as immune cell mobilization, metabolism, biogenesis of immunoregulatory molecules, etc. The chronic duration of cardiovascular diseases (CVD) has been increasingly considered to be triggered by uncontrolled pathologic immune reactions from myeloid cells and lymphocytes. Considering the potential anti-inflammatory effect of the traditional antihypertensive ACE inhibitor (ACEi), we attempt to elucidate whether ACE and its catalytically relevant substances as well as signaling pathways play a role in the immunity-related pathogenesis of common CVD, such as arterial hypertension, atherosclerosis and arrythmias. ACEi was also reported to benefit the prognoses of COVID-19-positive patients with CVD, and COVID-19 disease with preexisting CVD or subsequent cardiovascular damage is featured by a significant influx of immune cells and proinflammatory molecules, suggesting that ACE may also participate in COVID-19 induced cardiovascular injury, because COVID-19 disease basically triggers an overactive pathologic immune response. Hopefully, the ACE inhibition and manipulation of those associated bioactive signals could supplement the current medicinal management of various CVD and bring greater benefit to patients' cardiovascular health.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

RIPK3 and caspase-8 interpret cytokine signals to regulate ILC3 survival in the gut

Group 3 innate lymphoid cells (ILC3s) are abundant in the developing or healthy intestine to critically support tissue homeostasis in response to microbial colonization. However, intestinal ILC3s are reduced during chronic infections, colorectal cancer, or inflammatory bowel disease (IBD), and the mechanisms driving these alterations remain poorly understood. Here we employed RNA sequencing of ILC3s from IBD patients and observed a significant upregulation of RIPK3, the central regulator of necroptosis, during intestinal inflammation. This was modeled in mice where we found that intestinal ILC3s express RIPK3, with conventional (c)ILC3s exhibiting high RIPK3 and low levels of pro-survival genes relative to lymphoid tissue inducer (LTi)-like ILC3s. ILC3-specific RIPK3 is promoted by gut microbiota, further upregulated following enteric infection, and dependent upon IL-23R and STAT3 signaling. However, lineage-specific deletion of RIPK3 revealed a redundant role in ILC3 survival, due to a blockade of RIPK3-mediated necroptosis by caspase 8, which was also activated in response to enteric infection. In contrast, lineage-specific deletion of caspase 8 resulted in loss of cILC3s from the healthy intestine and all ILC3 subsets during enteric infection, which increased pathogen burdens and gut inflammation. This function of caspase 8 required catalytic activity induced by TNF or TL1A and was dispensable if RIPK3 was simultaneously deleted. Caspase 8 activation and cell death were associated with increased Fas on ILC3s, and the Fas-FasL pathway was upregulated by cILC3s during enteric infection, which could restrain the abundance of intestinal ILC3s. Collectively, these data reveal that interpretation of key cytokine signals controls ILC3 survival following microbial challenge, and that an imbalance of these pathways, such as in IBD or across ILC3 subsets, provokes depletion of tissue-protective ILC3s from the inflamed intestine.

No Time to Die: How Cytomegaloviruses Suppress Apoptosis, Necroptosis, and Pyroptosis

Viruses are obligate intracellular pathogens as their replication depends on the metabolism of the host cell. The induction of cellular suicide, known as programmed cell death (PCD), has the potential to hinder viral replication and act as a first line of defense against viral pathogens. Apoptosis, necroptosis, and pyroptosis are three important PCD modalities. Different signaling pathways are involved in their execution, and they also differ in their ability to cause inflammation. Cytomegaloviruses (CMV), beta-herpesviruses with large double-stranded DNA genomes, encode a great variety of immune evasion genes, including several cell death suppressors. While CMV inhibitors of apoptosis and necroptosis have been known and studied for years, the first pyroptosis inhibitor has been identified and characterized only recently. Here, we describe how human and murine CMV interfere with apoptosis, necroptosis, and pyroptosis signaling pathways. We also discuss the importance of the different PCD forms and their viral inhibitors for the containment of viral replication and spread in vivo.

Gas6-Axl signal promotes indoor VOCs exposure-induced pulmonary fibrosis via pulmonary microvascular endothelial cells-fibroblasts cross-talk

Volatile organic compounds (VOCs) as environmental pollutants were associated with respiratory diseases. Pulmonary fibrosis (PF) was characterized by an increase of extracellular matrix, leading to deterioration of lung function. The adverse effects on lung and the potential mechanism underlying VOCs induced PF had not been elucidated clearly. In this study, the indoor VOCs exposure mouse model along with an ex vivo biosensor assay was established. Based on scRNA-seq analysis, the adverse effects on lung and potential molecular mechanism were studied. Herein, the results showed that VOCs exposure from indoor decoration contributed to decreased lung function and facilitated pulmonary fibrosis in mice. Then, the whole lung cell atlas after VOCs exposure and the heterogeneity of fibroblasts were revealed. We explored the molecular interactions among various pulmonary cells, suggesting that endothelial cells contributed to fibroblasts activation in response to VOCs exposure. Mechanistically, pulmonary microvascular endothelial cells (MPVECs) secreted Gas6 after VOCs-induced PANoptosis phenotype, bound to the Axl in fibroblasts, and then activated fibroblasts. Moreover, Atf3 as the key gene negatively regulated PANoptosis phenotype to ameliorate fibrosis induced by VOCs exposure. These novel findings provided a new perspective about MPVECs could serve as the initiating factor of PF induced by VOCs exposure.

Cell Death and Survival Mechanisms in Cholangiocarcinogenesis

Cholangiocarcinoma (CCA) and other liver cancer subtypes often develop in damaged organs. Physiological agents or extrinsic factors, like toxins, can induce cell death in such tissues, triggering compensatory proliferation and inflammation. Depending on extracellular and intracellular factors, different mechanisms, like apoptosis, necroptosis, ferroptosis, or autophagy, can be triggered. Each of them can lead to protumorigenic or anti-tumorigenic events within a cell or through regulation of the microenvironment. However, the exact role of each cell death mechanism in CCA onset, progression, and treatment is not well known. Here, we summarize current knowledge of different cell death mechanisms in patients with CCA and preclinical CCA research. We discuss cell death-related drugs with relevance to CCA treatment and how they could be used in the future to improve targeted CCA therapy.

Oxidative cell death in cancer: mechanisms and therapeutic opportunities

Reactive oxygen species (ROS) are highly reactive oxygen-containing molecules generated as natural byproducts during cellular processes, including metabolism. Under normal conditions, ROS play crucial roles in diverse cellular functions, including cell signaling and immune responses. However, a disturbance in the balance between ROS production and cellular antioxidant defenses can lead to an excessive ROS buildup, causing oxidative stress. This stress damages essential cellular components, including lipids, proteins, and DNA, potentially culminating in oxidative cell death. This form of cell death can take various forms, such as ferroptosis, apoptosis, necroptosis, pyroptosis, paraptosis, parthanatos, and oxeiptosis, each displaying distinct genetic, biochemical, and signaling characteristics. The investigation of oxidative cell death holds promise for the development of pharmacological agents that are used to prevent tumorigenesis or treat established cancer. Specifically, targeting key antioxidant proteins, such as SLC7A11, GCLC, GPX4, TXN, and TXNRD, represents an emerging approach for inducing oxidative cell death in cancer cells. This review provides a comprehensive summary of recent progress, opportunities, and challenges in targeting oxidative cell death for cancer therapy.

Identification of programmed cell death-related genes and diagnostic biomarkers in endometriosis using a machine learning and Mendelian randomization approach

Background

Endometriosis (EM) is a prevalent gynecological disorder frequently associated with irregular menstruation and infertility. Programmed cell death (PCD) is pivotal in the pathophysiological mechanisms underlying EM. Despite this, the precise pathogenesis of EM remains poorly understood, leading to diagnostic delays. Consequently, identifying biomarkers associated with PCD is critical for advancing the diagnosis and treatment of EM.

Methods

This study used datasets from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs) following preprocessing. By cross-referencing these DEGs with genes associated with PCD, differentially expressed PCD-related genes (DPGs) were identified. Enrichment analyses for KEGG and GO pathways were conducted on these DPGs. Additionally, Mendelian randomization and machine learning techniques were applied to identify biomarkers strongly associated with EM.

Results

The study identified three pivotal biomarkers: TNFSF12, AP3M1, and PDK2, and established a diagnostic model for EM based on these genes. The results revealed a marked upregulation of TNFSF12 and PDK2 in EM samples, coupled with a significant downregulation of AP3M1. Single-cell analysis further underscored the potential of TNFSF12, AP3M1, and PDK2 as biomarkers for EM. Additionally, molecular docking studies demonstrated that these genes exhibit significant binding affinities with drugs currently utilized in clinical practice.

Conclusion

This study systematically elucidated the molecular characteristics of PCD in EM and identified TNFSF12, AP3M1, and PDK2 as key biomarkers. These findings provide new directions for the early diagnosis and personalized treatment of EM.

Identification of a marine-derived sesquiterpenoid, Compound-8, that inhibits tumour necrosis factor-induced cell death by blocking complex II assembly

BACKGROUND AND PURPOSE

Tumour necrosis factor (TNF) is a pleiotropic inflammatory cytokine that not only directly induces inflammatory gene expression but also triggers apoptotic and necroptotic cell death, which leads to tissue damage and indirectly exacerbates inflammation. Thus, identification of inhibitors for TNF-induced cell death has broad therapeutic relevance for TNF-related inflammatory diseases. In the present study, we isolated and identified a marine fungus-derived sesquiterpenoid, 9α,14-dihydroxy-6β-p-nitrobenzoylcinnamolide (named as Cpd-8), that inhibits TNF receptor superfamily-induced cell death by preventing the formation of cytosolic death complex II.

EXPERIMENTAL APPROACH

Marine sponge-associated fungi were cultured and the secondary metabolites were extracted to yield pure compounds. Cell viability was measured by ATP-Glo cell viability assay. The effects of Cpd-8 on TNF signalling pathway were investigated by western blotting, immunoprecipitation, and immunofluorescence assays. A mouse model of acute liver injury (ALI) was employed to explore the protection effect of Cpd-8, in vivo.

KEY RESULTS

Cpd-8 selectively inhibits TNF receptor superfamily-induced apoptosis and necroptosis. Cpd-8 prevents the formation of cytosolic death complex II and subsequent RIPK1-RIPK3 necrosome, while it has no effect on TNF receptor I (TNFR1) internalization and the formation of complex I in TNF signalling pathway. In vivo, Cpd-8 protects mice against TNF-α/D-GalN-induced ALI.

CONCLUSION AND IMPLICATIONS

A marine fungus-derived sesquiterpenoid, Cpd-8, inhibits TNF receptor superfamily-induced cell death, both in vitro and in vivo. This study not only provides a useful research tool to investigate the regulatory mechanisms of TNF-induced cell death but also identifies a promising lead compound for future drug development.

Sphingolipid metabolism and regulated cell death in malignant melanoma

Malignant melanoma (MM) is a highly invasive and therapeutically resistant skin malignancy, posing a significant clinical challenge in its treatment. Programmed cell death plays a crucial role in the occurrence and progression of MM. Sphingolipids (SP), as a class of bioactive lipids, may be associated with many kinds of diseases. SPs regulate various forms of programmed cell death in tumors, including apoptosis, necroptosis, ferroptosis, and more. This review will delve into the mechanisms by which different types of SPs modulate various forms of programmed cell death in MM, such as their regulation of cell membrane permeability and signaling pathways, and how they influence the survival and death fate of MM cells. An in-depth exploration of the role of SPs in programmed cell death in MM aids in unraveling the molecular mechanisms of melanoma development and holds significant importance in developing novel therapeutic strategies.

Exploring necrosis-associated mitochondrial gene signatures: revealing their role in prognosis and immunotherapy of renal clear cell carcinoma

Mitochondrial dysfunction and necrotic apoptosis, pivotal in therapeutic strategies for multiple diseases, lack comprehensive understanding in the context of renal clear cell carcinoma (ccRCC). This study explores their potential as valuable tools for ccRCC prediction, prevention, and personalized medical care. Transcriptomic and clinical datasets were acquired from the Cancer Genome Atlas (TCGA) repository. Mitochondrial and necrosis-associated gene sets were sourced from MitoCarta3.0 and the KEGG Pathway databases, respectively. Six necrosis-related mitochondrial genes (nc-MTGs) with prognostic significance were analyzed and screened, and a prognostic model was constructed. The accuracy of the model was verified using external data (E-MTAB-1980). TISCH was used to explore nc-MTGs at the cellular level. Finally, the expression level of BH3 interacting domain death agonist (BID) in ccRCC cell line was detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), and the effect of BID down-regulation on tumor cell migration was verified by transwell assays and wound-healing experiments. We established and validated a prognostic model for clear cell renal cell carcinoma (ccRCC) utilizing six necrosis-related mitochondrial genes (nc-MTGs), affirming its efficacy in evaluating tumor progression. RT-PCR results showed that BID expression was up-regulated in ccRCC tissues compared with controls and exhibited oncogenic effects. In vitro cell function experiments showed that BID may be an important factor affecting the migration of ccRCC. Our study is the first to elucidate the biological functions and prognostic significance of mitochondrial molecules related to necroptosis, providing a new way to evaluate mitochondrial therapeutics in patients with ccRCC.

Programmed cell death, from liver Ischemia-Reperfusion injury perspective: An overview

Liver ischemia-reperfusion injury (LIRI) commonly occurs in liver resection, liver transplantation, shock, and other hemorrhagic conditions, resulting in profound local and systemic effects via associated inflammatory responses and hepatic cell death. Hepatocyte death is a significant component of LIRI and its mechanism was previously thought to be limited to apoptosis and necrosis. With the discovery of novel types of programmed cell death (PCD), necroptosis, ferroptosis, pyroptosis, autophagy, NETosis, and parthanatos have been shown to be involved in LIRI. Understanding the mechanisms underlying cell death following LIRI is indispensable to mitigating the widespread effects of LIRI. Here, we review the roles of different PCD and discuss potential therapy in LIRI.

Research Progress on Micro(nano)plastic-Induced Programmed Cell Death Associated with Disease Risks

Due to their robust migration capabilities, slow degradation, and propensity for adsorbing environmental pollutants, micro(nano)plastics (MNPs) are pervasive across diverse ecosystems. They infiltrate various organisms within different food chains through multiple pathways including inhalation and dermal contact, and pose a significant environmental challenge in the 21st century. Research indicates that MNPs pose health threats to a broad range of organisms, including humans. Currently, extensive detection data and studies using experimental animals and in vitro cell culture indicate that MNPs can trigger various forms of programmed cell death (PCD) and can induce various diseases. This review provides a comprehensive and systematic analysis of different MNP-induced PCD processes, including pyroptosis, ferroptosis, autophagy, necroptosis, and apoptosis, based on recent research findings and focuses on elucidating the links between PCD and diseases. Additionally, targeted therapeutic interventions for these diseases are described. This review provides original insights into the opportunities and challenges posed by current research findings. This review evaluates ways to mitigate various diseases resulting from cell death patterns. Moreover, this paper enhances the understanding of the biohazards associated with MNPs by providing a systematic reference for subsequent toxicological research and health risk mitigation efforts.

VDX-111, a novel small molecule, induces necroptosis to inhibit ovarian cancer progression

Epithelial ovarian cancers that are nonhomologous recombination deficient, as well as those that are recurrent and in a platinum-resistant state, have limited therapeutic options. The objectives of this study were to characterize the mechanism of action and investigate the therapeutic potential of a small molecule, VDX-111, against ovarian cancer. We examined the ability of VDX-111 to inhibit the growth of a panel of ovarian cancer cell lines, focusing on BRCA wild-type lines. We found that VDX-111 causes a dose-dependent loss of cell viability across ovarian cancer cell lines. Reverse phase protein array (RPPA) analysis was used to identify changes in cell signaling in response to VDX-111 treatment. An RPPA analysis performed on cells treated with VDX-111 detected changes in cell signaling related to autophagy and necroptosis. Immunoblots of OVCAR3 and SNU8 cells confirmed a dose-dependent increase in LC3A/B and RIPK1. Incucyte live cell imaging was used to measure cell proliferation and death in response to VDX-111 alone and with inhibitors of apoptosis, necroptosis, and autophagy. Annexin/PI assays suggested predominantly nonapoptotic cell death, while real-time kinetic imaging of cell growth indicated the necroptosis inhibitor, necrostatin-1, attenuates VDX-111-induced loss of cell viability, suggesting a necroptosis-dependent mechanism. Furthermore, VDX-111 inhibited tumor growth in patient-derived xenograft and syngeneic murine models. In conclusion, the cytotoxic effects of VDX-111 seen in vitro and in vivo appear to occur in a necroptosis-dependent manner and may promote an antitumor immune response.

Spatiotemporal Control of Inflammatory Lytic Cell Death Through Optogenetic Induction of RIPK3 Oligomerization

Necroptosis is a programmed lytic cell death involving active cytokine production and plasma membrane rupture through distinct signaling cascades. However, it remains challenging to delineate this inflammatory cell death pathway at specific signaling nodes with spatiotemporal accuracy. To address this challenge, we developed an optogenetic system, termed Light-activatable Receptor-Interacting Protein Kinase 3 or La-RIPK3, to enable ligand-free, optical induction of RIPK3 oligomerization. La-RIPK3 activation dissects RIPK3-centric lytic cell death through the induction of RIPK3-containing necrosome, which mediates cytokine production and plasma membrane rupture. Bulk RNA-Seq analysis reveals that RIPK3 oligomerization results in partially overlapped gene expression compared to pharmacological induction of necroptosis. Additionally, La-RIPK3 activates separated groups of genes regulated by RIPK3 kinase-dependent and -independent processes. Using patterned light stimulation delivered by a spatial light modulator, we demonstrate precise spatiotemporal control of necroptosis in La-RIPK3-transduced HT-29 cells. Optogenetic control of proinflammatory lytic cell death could lead to the development of innovative experimental strategies to finetune the immune landscape for disease intervention.

Mitophagy-regulated Necroptosis plays a vital role in the nephrotoxicity of Fumonisin B1 in vivo and in vitro

Fumonisin B1 (FB1), one of the most widely distributed mycotoxins found in grains and feeds as contaminants, affects many organs including the kidney once ingested. However, the nephrotoxicity of FB1 remains to be further uncovered. The connection between necroptosis and nephrotoxicity of FB1 has been investigated in this study. The results showed that mice exposed to high doses of FB1 (2.25 mg/kg b.w.) developed kidney damage, with significant increases in proinflammatory cytokines (Il-6, Il-1β), kidney injury-related markers (Ngal, Ntn-1), and gene expressions linked to necroptosis (Ripk1, Ripk3, Mlkl). The concentration-dependent damage effects of FB1 on PK-15 cells contain cytotoxicity, cellular inflammatory response, and necroptosis. These FB1-induced effects can be neutralized by pretreatment with the necroptosis inhibitor Nec-1. Additionally, FB1 caused mitochondrial damage and mitophagy in vivo and in vitro, whereas Mdivi-1, a mitophagy inhibitor, prevented these effects on PK-15 cells as well as, more crucially, necroptosis. In conclusion, the RIPK1/RIPK3/MLKL signal route of necroptosis, which may be controlled by mitophagy, mediated nephrotoxicity of FB1. Our findings clarify the underlying molecular pathways of FB1-induced nephrotoxicity.

Therapeutic strategies of targeting non-apoptotic regulated cell death (RCD) with small-molecule compounds in cancer

Regulated cell death (RCD) is a controlled form of cell death orchestrated by one or more cascading signaling pathways, making it amenable to pharmacological intervention. RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis, facilitating development, and modulating immunity. Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival. Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse, comparable to apoptosis. Moreover, they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs. With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines, a growing number of small-molecule compounds targeting single or multiple pathways have been discovered, providing novel strategies for current cancer therapy. In this review, we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines, mainly including autophagy-dependent cell death, ferroptosis, cuproptosis, disulfidptosis, necroptosis, pyroptosis, alkaliptosis, oxeiptosis, parthanatos, mitochondrial permeability transition (MPT)-driven necrosis, entotic cell death, NETotic cell death, lysosome-dependent cell death, and immunogenic cell death (ICD). Furthermore, we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds. In brief, these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines, ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

A novel signature constructed by mitochondrial function and cell death-related gene for the prediction of prognosis in bladder cancer

Bladder urothelial carcinoma (BLCA) presents a persistent challenge in clinical management. Despite recent advancements demonstrating the BLCA efficacy of immune checkpoint inhibitors (ICI) in BLCA patients, there remains a critical need to identify and expand the subset of individuals who benefit from this treatment. Mitochondria, as pivotal regulators of various cell death pathways in eukaryotic cells, exert significant influence over tumor cell fate and survival. In this study, our objective was to investigate biomarkers centered around mitochondrial function and cell death mechanisms to facilitate prognostic prediction and guide therapeutic decision-making in BLCA. Utilizing ssGSEA and LASSO regression, we developed a prognostic signature termed mitochondrial function and cell death (mtPCD). Subsequently, we evaluated the associations between mtPCD score and diverse clinical outcomes, including prognosis, functional pathway enrichment, immune cell infiltration, immunotherapy response analysis and drug sensitivity, within high- and low-risk subgroups. Additionally, we employed single-cell level functional assays, RT-qPCR, and immunohistochemistry to validate the differential expression of genes comprising the mtPCD signature. The mtPCD signature comprises a panel of 10 highly influential genes, strongly correlated with survival outcomes in BLCA patients and exhibiting robust predictive capabilities. Importantly, individuals classified as high-risk according to mtPCD score displayed a subdued overall immune response, characterized by diminished immunotherapeutic efficacy. In summary, our findings highlight the development of a novel prognostic signature, which not only holds promise as a biomarker for BLCA prognosis but also offers insights into the immune landscape of BLCA. This paradigm may pave the way for personalized treatment strategies in BLCA management.

Redox modulator iron complexes trigger intrinsic apoptosis pathway in cancer cells

The emergence of multidrug resistance in cancer cells necessitates the development of new therapeutic modalities. One way cancer cells orchestrate energy metabolism and redox homeostasis is through overloaded iron pools directed by iron regulatory proteins, including transferrin. Here, we demonstrate that targeting redox homeostasis using nitrogen-based heterocyclic iron chelators and their iron complexes efficiently prevents the proliferation of liver cancer cells (EC50: 340 nM for IITK4003) and liver cancer 3D spheroids. These iron complexes generate highly reactive Fe(IV)=O species and accumulate lipid peroxides to promote oxidative stress in cells that impair mitochondrial function. Subsequent leakage of mitochondrial cytochrome c activates the caspase cascade to trigger the intrinsic apoptosis pathway in cancer cells. This strategy could be applied to leverage the inherent iron overload in cancer cells to selectively promote intrinsic cellular apoptosis for the development of unique iron-complex-based anticancer therapeutics.

The fate and function of non-coding RNAs during necroptosis

Necroptosis is a novel form of cell death which is activated when apoptotic cell death signals are disrupted. Accumulating body of observations suggests that noncoding RNAs, which are the lately discovered mystery of the human genome, are significantly associated with necroptotic signaling circuitry. The fate and function of miRNAs have been well documented in human disease, especially cancer. Recently, lncRNAs have gained much attention due to their diverse regulatory functions. Although available studies are currently based on bioinformatic analysis, predicted interactions desires further attention, as these hold significant promise and should not be overlooked. In the light of these, here we comprehensively review and discuss noncoding RNA molecules that play significant roles during execution of necroptotic cell death.

Cell death shapes cancer immunity: spotlighting PANoptosis

PANoptosis represents a novel type of programmed cell death (PCD) with distinctive features that incorporate elements of pyroptosis, apoptosis, and necroptosis. PANoptosis is governed by a newly discovered cytoplasmic multimeric protein complex known as the PANoptosome. Unlike each of these PCD types individually, PANoptosis is still in the early stages of research and warrants further exploration of its specific regulatory mechanisms and primary targets. In this review, we provide a brief overview of the conceptual framework and molecular components of PANoptosis. In addition, we highlight recent advances in the understanding of the molecular mechanisms and therapeutic applications of PANoptosis. By elucidating the complex crosstalk between pyroptosis, apoptosis and necroptosis and summarizing the functional consequences of PANoptosis with a special focus on the tumor immune microenvironment, this review aims to provide a theoretical basis for the potential application of PANoptosis in cancer therapy.

Necroptosis in bacterial infections

Necroptosis, a recently discovered form of cell-programmed death that is distinct from apoptosis, has been confirmed to play a significant role in the pathogenesis of bacterial infections in various animal models. Necroptosis is advantageous to the host, but in some cases, it can be detrimental. To understand the impact of necroptosis on the pathogenesis of bacterial infections, we described the roles and molecular mechanisms of necroptosis caused by different bacterial infections in this review.

Exploiting cell death and tumor immunity in cancer therapy: challenges and future directions

Cancer remains a significant global challenge, with escalating incidence rates and a substantial burden on healthcare systems worldwide. Herein, we present an in-depth exploration of the intricate interplay between cancer cell death pathways and tumor immunity within the tumor microenvironment (TME). We begin by elucidating the epidemiological landscape of cancer, highlighting its pervasive impact on premature mortality and the pronounced burden in regions such as Asia and Africa. Our analysis centers on the pivotal concept of immunogenic cell death (ICD), whereby cancer cells succumbing to specific stimuli undergo a transformation that elicits robust anti-tumor immune responses. We scrutinize the mechanisms underpinning ICD induction, emphasizing the release of damage-associated molecular patterns (DAMPs) and tumor-associated antigens (TAAs) as key triggers for dendritic cell (DC) activation and subsequent T cell priming. Moreover, we explore the contributions of non-apoptotic RCD pathways, including necroptosis, ferroptosis, and pyroptosis, to tumor immunity within the TME. Emerging evidence suggests that these alternative cell death modalities possess immunogenic properties and can synergize with conventional treatments to bolster anti-tumor immune responses. Furthermore, we discuss the therapeutic implications of targeting the TME for cancer treatment, highlighting strategies to harness immunogenic cell death and manipulate non-apoptotic cell death pathways for therapeutic benefit. By elucidating the intricate crosstalk between cancer cell death and immune modulation within the TME, this review aims to pave the way for the development of novel cancer therapies that exploit the interplay between cell death mechanisms and tumor immunity and overcome Challenges in the Development and implementation of Novel Therapies.

Apoptosis in post-streptococcal glomerulonephritis and mechanisms for failed of inflammation resolution

Post-streptococcal glomerulonephritis is a condition resulting from infection by group A beta-hemolytic streptococcus. The main mechanism involves the formation of immune complexes formed in the circulation or in situ on the glomerular basement membrane, which activates complement and causes various inflammatory processes. Cellular mechanisms have been reported in the induction of kidney damage represented by the infiltration of innate cells (neutrophils and monocyte/macrophages) and adaptive cells (CD4 + lymphocytes and CD8 + lymphocytes) of the immune system. These cells induce kidney damage through various mechanisms. It has been reported that nephritogenic antigens are capable of inducing inflammatory processes early, even before the formation of immune complexes. Usually, this disease progresses towards clinical and renal normalization; however, in a smaller number of patients, it evolves into chronicity and persistent kidney damage. Hypotheses have been proposed regarding the mechanisms underlying this progression to chronicity including failure to induce apoptosis and failure to phagocytose apoptotic cells, allowing these cells to undergo membrane permeabilization and release pro-inflammatory molecules into the environment, thereby perpetuating renal inflammation. Other mechanisms involved include persistent infection, genetic background of the host's complement system, tubulointerstitial changes, and pre-existing kidney damage due to old age and comorbidities.

Targeting immunogenic cell stress and death for cancer therapy

Immunogenic cell death (ICD), which results from insufficient cellular adaptation to specific stressors, occupies a central position in the development of novel anticancer treatments. Several therapeutic strategies to elicit ICD - either as standalone approaches or as means to convert immunologically cold tumours that are insensitive to immunotherapy into hot and immunotherapy-sensitive lesions - are being actively pursued. However, the development of ICD-inducing treatments is hindered by various obstacles. Some of these relate to the intrinsic complexity of cancer cell biology, whereas others arise from the use of conventional therapeutic strategies that were developed according to immune-agnostic principles. Moreover, current discovery platforms for the development of novel ICD inducers suffer from limitations that must be addressed to improve bench-to-bedside translational efforts. An improved appreciation of the conceptual difference between key factors that discriminate distinct forms of cell death will assist the design of clinically viable ICD inducers.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Targeting NF-κB in Hepatic Ischemia-Reperfusion Alleviation: from Signaling Networks to Therapeutic Targeting

Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver trauma, resection, and transplantation that can lead to liver dysfunction and failure. Scholars have proposed a variety of liver protection methods aimed at reducing ischemia-reperfusion damage, but there is still a lack of effective treatment methods, which urgently needs to find new effective treatment methods for patients. Many studies have reported that signaling pathway plays a key role in HIRI pathological process and liver function recovery mechanism, among which nuclear transfer factor-κB (NF-κB) signaling pathway is one of the signal transduction closely related to disease. NF-κB pathway is closely related to HIRI pathologic process, and inhibition of this pathway can delay oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction. In addition, NF-κB can also interact with PI3K/Akt, MAPK, and Nrf2 signaling pathways to participate in HIRI regulation. Based on the role of NF-κB pathway in HIRI, it may be a potential target pathway for HIRI. This review emphasizes the role of inhibiting the NF-κB signaling pathway in oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction in HIRI, as well as the effects of related drugs or inhibitors targeting NF-κB on HIRI. The objective of this review is to elucidate the role and mechanism of NF-κB pathway in HIRI, emphasize the important role of NF-κB pathway in the prevention and treatment of HIRI, and provide a theoretical basis for the target NF-κB pathway as a therapy for HIRI.

Research progress on morphology and mechanism of programmed cell death

Programmed cell death (PCD) is a basic process of life that is closely related to the growth, development, aging and disease of organisms and is one of the hotspots of life science research today. PCD is a kind of genetic control, autonomous and orderly important cell death that involves the activation, expression, and regulation of a series of genes. In recent years, with the deepening of research in this field, new mechanisms of multiple PCD pathways have been revealed. This article reviews and summarizes the multiple PCD pathways that have been discovered, analyses and compares the morphological characteristics and biomarkers of different types of PCD, and briefly discusses the role of various types of PCD in the diagnosis and treatment of different diseases, especially malignant tumors.

Emerging regulatory mechanisms in cardiovascular disease: Ferroptosis

Ferroptosis, distinct from apoptosis, necrosis, autophagy, and other types of cell death, is a novel iron-dependent regulated cell death characterized by the accumulation of lipid peroxides and redox imbalance with distinct morphological, biochemical, and genetic features. Dysregulation of iron homeostasis, the disruption of antioxidative stress pathways and lipid peroxidation are crucial in ferroptosis. Ferroptosis is involved in the pathogenesis of several cardiovascular diseases, including atherosclerosis, cardiomyopathy, myocardial infarction, ischemia-reperfusion injury, abdominal aortic aneurysm, aortic dissection, and heart failure. Therefore, a comprehensive understanding of the mechanisms that regulate ferroptosis in cardiovascular diseases will enhance the prevention and treatment of these diseases. This review discusses the latest findings on the molecular mechanisms of ferroptosis and its regulation in cardiovascular diseases, the application of ferroptosis modulators in cardiovascular diseases, and the role of traditional Chinese medicines in ferroptosis regulation to provide a comprehensive understanding of the pathogenesis of cardiovascular diseases and identify new prevention and treatment options.

Nanomaterials-induced programmed cell death: Focus on mitochondria

Nanomaterials are widely utilized in several domains, such as everyday life, societal manufacturing, and biomedical applications, which expand the potential for nanomaterials to penetrate biological barriers and interact with cells. Multiple studies have concentrated on the particular or improper utilization of nanomaterials, resulting in cellular death. The primary mode of cell death caused by nanotoxicity is programmable cell death, which includes apoptosis, ferroptosis, necroptosis, and pyroptosis. Based on our prior publications and latest research, mitochondria have a vital function in facilitating programmed cell death caused by nanomaterials, as well as initiating or transmitting death signal pathways associated with it. Therefore, this review takes mitochondria as the focal point to investigate the internal molecular mechanism of nanomaterial-induced programmed cell death, with the aim of identifying potential targets for prevention and treatment in related studies.

Synthesis and preclinical evaluation of 11C-labeled 7-Oxo-2,4,5,7-tetrahydro-6H-pyrazolo[3,4-c]pyridine radioligands for RIPK1 positron emission tomography imaging

Targeting receptor-interacting protein kinase 1 (RIPK1) has emerged as a promising therapeutic strategy for various neurodegenerative disorders. The development of a positron emission tomography (PET) probe for brain RIPK1 imaging could offer a valuable tool to assess therapeutic effectiveness and uncover the neuropathology associated with RIPK1. In this study, we present the development and characterization of two new PET radioligands, [11C]PB218 and [11C]PB220, which have the potential to facilitate brain RIPK1 imaging. [11C]PB218 and [11C]PB220 were successfully synthesized with a high radiochemical yield (34 % - 42 %) and molar activity (293 - 314 GBq/µmol). PET imaging characterization of two radioligands was conducted in rodents, demonstrating that both newly developed tracers have good brain penetration (maximum SUV = 0.9 - 1.0) and appropriate brain clearance kinetic profiles. Notably, [11C]PB218 has a more favorable binding specificity than [11C]PB220. A PET/MR study of [11C]PB218 in a non-human primate exhibited good brain penetration, desirable kinetic properties, and a safe profile, thus supporting the translational applicability of our new probe. These investigations enable further translational exploration of [11C]PB218 for drug discovery and PET probe development targeting RIPK1.

RIPK3 signaling and its role in regulated cell death and diseases

Receptor-interacting protein kinase 3 (RIPK3), a member of the receptor-interacting protein kinase (RIPK) family with serine/threonine protein kinase activity, interacts with RIPK1 to generate necrosomes, which trigger caspase-independent programmed necrosis. As a vital component of necrosomes, RIPK3 plays an indispensable role in necroptosis, which is crucial for human life and health. In addition, RIPK3 participates in the pathological process of several infections, aseptic inflammatory diseases, and tumors (including tumor-promoting and -suppressive activities) by regulating autophagy, cell proliferation, and the metabolism and production of chemokines/cytokines. This review summarizes the recent research progress of the regulators of the RIPK3 signaling pathway and discusses the potential role of RIPK3/necroptosis in the aetiopathogenesis of various diseases. An in-depth understanding of the mechanisms and functions of RIPK3 may facilitate the development of novel therapeutic strategies.

Zooming in and Out of Programmed Cell Death in Osteoarthritis: A Scientometric and Visualized Analysis

During the past decade, mounting evidence has increasingly linked programmed cell death (PCD) to the progression and development of osteoarthritis (OA). There is a significant need for a thorough scientometric analysis that recapitulates the relationship between PCD and OA. This study aimed to collect articles and reviews focusing on PCD in OA, extracting data from January 1st, 2013, to October 31st, 2023, using the Web of Science. Various tools, including VOSviewer, CiteSpace, Pajek, Scimago Graphica, and the R package, were employed for scientometric and visualization analyses. Notably, China, the USA, and South Korea emerged as major contributors, collectively responsible for more than 85% of published papers and significantly influencing research in this field. Among different institutions, Shanghai Jiao Tong University, Xi'an Jiao Tong University, and Zhejiang University exhibited the highest productivity. Prolific authors included Wang Wei, Wang Jing, and Zhang Li. Osteoarthritis and Cartilage had the most publications in this area. Keywords related to PCD in OA prominently highlighted 'chondrocytes', 'inflammation', and 'oxidative stress', recognized as pivotal mechanisms contributing to PCD within OA. This study presents the first comprehensive scientometric analysis, offering a broad perspective on the knowledge framework and evolving patterns concerning PCD in relation to OA over the last decade. Such insights can aid researchers in comprehensively understanding this field and provide valuable directions for future explorations.

The CaMK Family Differentially Promotes Necroptosis and Mouse Cardiac Graft Injury and Rejection

Organ transplantation is associated with various forms of programmed cell death which can accelerate transplant injury and rejection. Targeting cell death in donor organs may represent a novel strategy for preventing allograft injury. We have previously demonstrated that necroptosis plays a key role in promoting transplant injury. Recently, we have found that mitochondria function is linked to necroptosis. However, it remains unknown how necroptosis signaling pathways regulate mitochondrial function during necroptosis. In this study, we investigated the receptor-interacting protein kinase 3 (RIPK3) mediated mitochondrial dysfunction and necroptosis. We demonstrate that the calmodulin-dependent protein kinase (CaMK) family members CaMK1, 2, and 4 form a complex with RIPK3 in mouse cardiac endothelial cells, to promote trans-phosphorylation during necroptosis. CaMK1 and 4 directly activated the dynamin-related protein-1 (Drp1), while CaMK2 indirectly activated Drp1 via the phosphoglycerate mutase 5 (PGAM5). The inhibition of CaMKs restored mitochondrial function and effectively prevented endothelial cell death. CaMKs inhibition inhibited activation of CaMKs and Drp1, and cell death and heart tissue injury (n = 6/group, p < 0.01) in a murine model of cardiac transplantation. Importantly, the inhibition of CaMKs greatly prolonged heart graft survival (n = 8/group, p < 0.01). In conclusion, CaMK family members orchestrate cell death in two different pathways and may be potential therapeutic targets in preventing cell death and transplant injury.

Necroptosis contributes to non-alcoholic fatty liver disease pathoetiology with promising diagnostic and therapeutic functions

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent type of chronic liver disease. However, the disease is underappreciated as a remarkable chronic disorder as there are rare managing strategies. Several studies have focused on determining NAFLD-caused hepatocyte death to elucidate the disease pathoetiology and suggest functional therapeutic and diagnostic options. Pyroptosis, ferroptosis, and necroptosis are the main subtypes of non-apoptotic regulated cell deaths (RCDs), each of which represents particular characteristics. Considering the complexity of the findings, the present study aimed to review these types of RCDs and their contribution to NAFLD progression, and subsequently discuss in detail the role of necroptosis in the pathoetiology, diagnosis, and treatment of the disease. The study revealed that necroptosis is involved in the occurrence of NAFLD and its progression towards steatohepatitis and cancer, hence it has potential in diagnostic and therapeutic approaches. Nevertheless, further studies are necessary.

Progress of research on the relationship between efferocytosis and tumor

Tumors are genetic changes that develop in an organism as a result of many internal and external causes. They affect the biological behavior of cells, cause them to grow independently, and give rise to new, perpetually proliferating organisms. Recent research has supported the critical function of tumor-associated macrophages in the development, progression, and metastasis of tumors through efferocytosis. Yet, there is still much to learn about the mechanisms behind their contribution to tumor pathological processes. As a result, it's critical to actively investigate how cytosolic processes contribute to the growth of tumors and to create novel therapeutic approaches.

The broad impact of cell death genes on the human disease phenome

Cell death mediated by genetically defined signaling pathways influences the health and dynamics of all tissues, however the tissue specificity of cell death pathways and the relationships between these pathways and human disease are not well understood. We analyzed the expression profiles of an array of 44 cell death genes involved in apoptosis, necroptosis, and pyroptosis cell death pathways across 49 human tissues from GTEx, to elucidate the landscape of cell death gene expression across human tissues, and the relationship between tissue-specific genetically determined expression and the human phenome. We uncovered unique cell death gene expression profiles across tissue types, suggesting there are physiologically distinct cell death programs in different tissues. Using summary statistics-based transcriptome wide association studies (TWAS) on human traits in the UK Biobank (n ~ 500,000), we evaluated 513 traits encompassing ICD-10 defined diagnoses and laboratory-derived traits. Our analysis revealed hundreds of significant (FDR < 0.05) associations between genetically regulated cell death gene expression and an array of human phenotypes encompassing both clinical diagnoses and hematologic parameters, which were independently validated in another large-scale DNA biobank (BioVU) at Vanderbilt University Medical Center (n = 94,474) with matching phenotypes. Cell death genes were highly enriched for significant associations with blood traits versus non-cell-death genes, with apoptosis-associated genes enriched for leukocyte and platelet traits. Our findings are also concordant with independently published studies (e.g. associations between BCL2L11/BIM expression and platelet & lymphocyte counts). Overall, these results suggest that cell death genes play distinct roles in their contribution to human phenotypes, and that cell death genes influence a diverse array of human traits.

Sodium sulfite triggered hepatic apoptosis, necroptosis, and pyroptosis by inducing mitochondrial damage in mice and AML-12 cells

Sodium sulfite (SS) is a biological derivative of the air pollutant sulfur dioxide, and is often used as a food and pharmaceutical additive. Improper or excessive SS exposure in liver cell death. The phenomenon of simultaneous regulation of apoptosis, necroptosis, and pyroptosis is defined as PANoptosis. However, the specific types of programmed cell death (PCD) caused by SS and their interconnections remain unclear. In the present study, C57BL/6 mice were orally administered SS for 30 d, consecutively, to establish an in vivo mouse exposure model. AML-12 cells were treated with SS for 24 h to establish an in vitro exposure model. The results showed that SS-induced mitochondrial reactive oxygen species (mtROS) accumulation activated the BAX/Bcl-2/caspase 3 pathway to trigger apoptosis and RIPK1/RIPK3/p-MLKL to trigger necroptosis. Interestingly, ROS-activated p-MLKL perforated not the cell membrane as well as the lysosomal membrane. We determined that p-MLKL mediates lysosomal membrane permeabilization (LMP), resulting in cathepsin B (CTSB) release. Furthermore, knockdown of MLKL, a CTSB inhibitor (CA074-ME) and an NLRP3 inhibitor (MCC950) alleviated SS-induced pyroptosis. In summary, our study showed that SS induced apoptosis and necroptosis though mtROS accumulation, whereas the activation of p-MLKL mediated NLRP3-dependent pyroptosis by causing CTSB leakage through LMP. This study comprehensively explored the mechanism unerlying SS-induced PCD and provided an experimental basis for p-MLKL as a potential regulatory protein in PANoptosis.

Outer membrane vesicles of avian pathogenic Escherichia coli induce necroptosis and NF-κB activation in chicken macrophages via RIPK1 mediation

Outer membrane vesicles (OMVs) are soluble mediators secreted by Gram-negative bacteria that are involved in communication. They can carry a variety of harmful molecules, which induce cytotoxic responses and inflammatory reactions in the absence of direct host cell-bacterium interactions. We previously reported the isolation of OMVs from avian pathogenic Escherichia coli (APEC) culture medium by ultracentrifugation, and characterized them as a substance capable of inducing the production of pro-inflammatory cytokines and causing tissue damage. However, the specific mechanisms by which APEC-secreted OMVs activate host cell death signaling and inflammation are poorly understood. Here, we show that OMVs are involved in the pathogenesis of APEC disease. In an APEC/chicken macrophage (HD11) coculture system, APEC significantly promoted HD11 cell death and inflammatory responses by secreting OMVs. Using western blotting analysis and specific pathway inhibitors, we demonstrated that the induction of HD11 death by APEC OMVs is associated with the activation of receptor interacting serine/threonine kinase 1 (RIPK1)-, receptor interacting serine/threonine kinase 3 (RIPK3)-, and mixed lineage kinase like pseudokinase (MLKL)-induced necroptosis. Notably, necroptosis inhibitor-1 (Nec-1), an RIPK1 inhibitor, reversed these effects. We also showed that APEC OMVs promote the activation of the NF-κB signaling pathway, leading to the phosphorylation of IκB-α and p65, the increased nuclear translocation of p65, and the significant upregulation of interleukin 1β (IL-1β) and IL-6 transcription. Importantly, APEC OMVs-induced IL-1β and IL-6 mRNA expression and the activation of the NF-κB signaling pathway were similarly significantly inhibited by a RIPK1-specific inhibitor. Based on these findings, we have established that RIPK1 plays a dual role in HD11 cells necroptosis and the proinflammatory cytokine (IL-1β and IL-6) expression induced by APEC OMVs. RIPK1 mediated the induction of necroptosis and the activation of the NF-κB in HD11 cells via APEC OMVs. The results of this study provide a basis for further investigation of the contribution of OMVs to the pathogenesis of APEC.

Defective prelamin A processing promotes unconventional necroptosis driven by nuclear RIPK1

Defects in the prelamin A processing enzyme caused by loss-of-function mutations in the ZMPSTE24 gene are responsible for a spectrum of progeroid disorders characterized by the accumulation of farnesylated prelamin A. Here we report that defective prelamin A processing triggers nuclear RIPK1-dependent signalling that leads to necroptosis and inflammation. We show that accumulated prelamin A recruits RIPK1 to the nucleus to facilitate its activation upon tumour necrosis factor stimulation in ZMPSTE24-deficient cells. Kinase-activated RIPK1 then promotes RIPK3-mediated MLKL activation in the nucleus, leading to nuclear envelope disruption and necroptosis. This signalling relies on prelamin A farnesylation, which anchors prelamin A to nuclear envelope to serve as a nucleation platform for necroptosis. Genetic inactivation of necroptosis ameliorates the progeroid phenotypes in Zmpste24-/- mice. Our findings identify an unconventional nuclear necroptosis pathway resulting from ZMPSTE24 deficiency with pathogenic consequences in progeroid disorder and suggest RIPK1 as a feasible target for prelamin A-associated progeroid disorders.

Macrophage Tim-3 maintains intestinal homeostasis in DSS-induced colitis by suppressing neutrophil necroptosis

T-cell immunoglobulin domain and mucin domain-3 (Tim-3) is a versatile immunomodulator that protects against intestinal inflammation. Necroptosis is a type of cell death that regulates intestinal homeostasis and inflammation. The mechanism(s) underlying the protective role of macrophage Tim-3 in intestinal inflammation is unclear; thus, we investigated whether specific Tim-3 knockdown in macrophages drives intestinal inflammation via necroptosis. Tim-3 protein and mRNA expression were assessed via double immunofluorescence staining and single-cell RNA sequencing (sc-RNA seq), respectively, in the colonic tissues of patients with inflammatory bowel disease (IBD) and healthy controls. Macrophage-specific Tim3-knockout (Tim-3M-KO) mice were generated to explore the function and mechanism of Tim-3 in dextran sodium sulfate (DSS)-induced colitis. Necroptosis was blocked by pharmacological inhibitors of receptor-interacting protein kinase (RIP)1, RIP3, and reactive oxygen species (ROS). Additionally, in vitro experiments were performed to assess the mechanisms of neutrophil necroptosis induced by Tim-3 knockdown macrophages. Although Tim-3 is relatively inactive in macrophages during colon homeostasis, it is highly active during colitis. Compared to those in controls, Tim-3M-KO mice showed increased susceptibility to colitis, higher colitis scores, and increased pro-inflammatory mediator expression. Following the administration of RIP1/RIP3 or ROS inhibitors, a significant reduction in intestinal inflammation symptoms was observed in DSS-treated Tim-3M-KO mice. Further analysis indicated the TLR4/NF-κB pathway in Tim-3 knockdown macrophages mediates the TNF-α-induced necroptosis pathway in neutrophils. Macrophage Tim-3 regulates neutrophil necroptosis via intracellular ROS signaling. Tim-3 knockdown macrophages can recruit neutrophils and induce neutrophil necroptosis, thereby damaging the intestinal mucosal barrier and triggering a vicious cycle in the development of colitis. Our results demonstrate a protective role of macrophage Tim-3 in maintaining gut homeostasis by inhibiting neutrophil necroptosis and provide novel insights into the pathogenesis of IBD.

PARP5A and RNF146 phase separation restrains RIPK1-dependent necroptosis

Phase separation is a vital mechanism that mediates the formation of biomolecular condensates and their functions. Necroptosis is a lytic form of programmed cell death mediated by RIPK1, RIPK3, and MLKL downstream of TNFR1 and has been implicated in mediating many human diseases. However, whether necroptosis is regulated by phase separation is not yet known. Here, we show that upon the induction of necroptosis and recruitment by the adaptor protein TAX1BP1, PARP5A and its binding partner RNF146 form liquid-like condensates by multivalent interactions to perform poly ADP-ribosylation (PARylation) and PARylation-dependent ubiquitination (PARdU) of activated RIPK1 in mouse embryonic fibroblasts. We show that PARdU predominantly occurs on the K376 residue of mouse RIPK1, which promotes proteasomal degradation of kinase-activated RIPK1 to restrain necroptosis. Our data demonstrate that PARdU on K376 of mouse RIPK1 provides an alternative cell death checkpoint mediated by phase separation-dependent control of necroptosis by PARP5A and RNF146.

PUMA/RIP3 Mediates Chemotherapy Response via Necroptosis and Local Immune Activation in Colorectal Cancer

Induction of programmed cell death (PCD) is a key cytotoxic effect of anticancer therapies. PCD is not confined to caspase-dependent apoptosis, but includes necroptosis, a regulated form of necrotic cell death controlled by receptor-interacting protein (RIP) kinases 1 and 3, and mixed lineage kinase domain-like (MLKL) pseudokinase. Necroptosis functions as a defense mechanism against oncogenic mutations and pathogens and can be induced by a variety of anticancer agents. However, the functional role and regulatory mechanisms of necroptosis in anticancer therapy are poorly understood. In this study, we found that RIP3-dependent but RIP1-independent necroptosis is engaged by 5-fluorouracil (5-FU) and other widely used antimetabolite drugs, and functions as a major mode of cell death in a subset of colorectal cancer cells that express RIP3. We identified a novel 5-FU-induced necroptosis pathway involving p53-mediated induction of the BH3-only Bcl-2 family protein, p53 upregulated modulator of apoptosis (PUMA), which promotes cytosolic release of mitochondrial DNA and stimulates its sensor z-DNA-binding protein 1 (ZBP1) to activate RIP3. PUMA/RIP3-dependent necroptosis mediates the in vitro and in vivo antitumor effects of 5-FU and promotes a robust antitumor immune response. Our findings provide a rationale for stimulating necroptosis to enhance tumor cell killing and antitumor immune response leading to improved colorectal cancer treatments.

Exosomes derived from programmed cell death: mechanism and biological significance

Exosomes are nanoscale extracellular vesicles present in bodily fluids that mediate intercellular communication by transferring bioactive molecules, thereby regulating a range of physiological and pathological processes. Exosomes can be secreted from nearly all cell types, and the biological function of exosomes is heterogeneous and depends on the donor cell type and state. Recent research has revealed that the levels of exosomes released from the endosomal system increase in cells undergoing programmed cell death. These exosomes play crucial roles in diseases, such as inflammation, tumors, and autoimmune diseases. However, there is currently a lack of systematic research on the differences in the biogenesis, secretion mechanisms, and composition of exosomes under different programmed cell death modalities. This review underscores the potential of exosomes as vital mediators of programmed cell death processes, highlighting the interconnection between exosome biosynthesis and the regulatory mechanisms governing cell death processes. Furthermore, we accentuate the prospect of leveraging exosomes for the development of innovative biomarkers and therapeutic strategies across various diseases.