The Role of Mitochondria in Pyroptosis

Activating MC4R Promotes Functional Recovery by Repressing Oxidative Stress-Mediated AIM2 Activation Post-spinal Cord Injury

Spinal cord injury (SCI) is a destructive neurological trauma that induces permanent sensory and motor impairment as well as a deficit in autonomic physiological function. Melanocortin receptor 4 (MC4R) is a G protein-linked receptor that is extensively expressed in the neural system and contributes to inhibiting inflammation, regulating mitochondrial function, and inducing programmed cell death. However, the effect of MC4R in the modulation of oxidative stress and whether this mechanism is related to the role of absent in melanoma 2 (AIM2) in SCI are not confirmed yet. In the current study, we demonstrated that MC4R is significantly increased in the neurons of spinal cords after trauma and oxidative stimulation of cells. Further, activation of MC4R by RO27-3225 effectively improved functional recovery, inhibited AIM2 activation, maintained mitochondrial homeostasis, repressed oxidative stress, and prevented Drp1 translocation to the mitochondria. Meanwhile, treating Drp1 inhibitors would be beneficial in reducing AIM2 activation, and activating AIM2 could abolish the protective effect of MC4R on neuron homeostasis. In conclusion, we demonstrated that MC4R protects against neural injury through a novel process by inhibiting mitochondrial dysfunction, oxidative stress, as well as AIM2 activation, which may serve as an available candidate for SCI therapy.

Polyhexamethylene guanidine phosphate induces pyroptosis via reactive oxygen species-regulated mitochondrial dysfunction in bronchial epithelial cells

Pyroptosis is a form of programmed cell death characterized by gasdermin (GSDM)-mediated pore formation in the cell membrane, resulting in the release of pro-inflammatory cytokines and cellular lysis. Increasing evidence has shown that pyroptosis is responsible for the progression of various pulmonary disorders. The inhalation of polyhexamethylene guanidine (PHMG) causes severe lung inflammation and pulmonary toxicity; however, the underlying mechanisms are unknown. Therefore, in this study, we investigate the role of pyroptosis in PHMG-induced pulmonary toxicity. We exposed bronchial epithelial cells, BEAS-2B, to PHMG phosphate (PHMG-p) and evaluated cell death type, reactive oxygen species (ROS) levels, and relative expression levels of pyroptosis-related proteins. Our data revealed that PHMG-p reduced viability and induced morphological alterations in BEAS-2B cells. Exposure to PHMG-p induced excessive accumulation of mitochondrial ROS (mtROS) in BEAS-2B cells. PHMG-p activated caspase-dependent apoptosis as well as NLRP3/caspase-1/GSDMD-mediated- and caspase-3/GSDME-mediated pyroptosis through mitochondrial oxidative stress in BEAS-2B cells. Notably, PHMG-p reduced mitochondrial respiratory function and induced the translocation of Bax and cleaved GSDM into the mitochondria, leading to mitochondrial dysfunction. Our results enhanced our understanding of PHMG-p-induced lung toxicity by demonstrating that PHMG-p induces pyroptosis via mtROS-induced mitochondrial dysfunction in bronchial epithelial cells.

Novel Re(I) Complexes as Potential Selective Theranostic Agents in Cancer Cells and In Vivo in Caenorhabditis elegans Tumoral Strains

A series of rhenium(I) complexes of the type fac-[Re(CO)3(N^N)L]0/+, Re1-Re9, was synthesized, where N^N = benzimidazole-derived bidentate ligand with an ester functionality and L = chloride or pyridine-type ligand. The new compounds demonstrated potent activity toward ovarian A2780 cancer cells. The most active complexes, Re7-Re9, incorporating 4-NMe2py, exhibited remarkable activity in 3D HeLa spheroids. The emission in the red region of Re9, which contains an electron-deficient benzothiazole moiety, allowed its operability as a bioimaging tool for in vitro and in vivo visualization. Re9 effectivity was tested in two different C. elegans tumoral strains, JK1466 and MT2124, to broaden the oncogenic pathways studied. The results showed that Re9 was able to reduce the tumor growth in both strains by increasing the ROS production inside the cells. Moreover, the selectivity of the compound toward cancerous cells was remarkable as it did not affect neither the development nor the progeny of the nematodes.

Molecular mechanisms of mitochondria-mediated ferroptosis: a potential target for antimalarial interventions

Ferroptosis is an iron-dependent form of regulated cell death characterized by glutathione (GSH) depletion, glutathione peroxidase 4 (GPX4) inactivation, and the build-up of lipotoxic reactive species. Ferroptosis-targeted induction is a promising therapeutic approach for addressing antimalarial drug resistance. In addition to being the primary source of intracellular energy supply and reactive oxygen species (ROS) generation, mitochondria actively participate in diverse forms of regulated cell death, including ferroptosis. Altered mitochondrial morphology and functionality are attributed to ferroptosis. Diverse mitochondria-related proteins and metabolic activities have been implicated in fine-tuning the action of ferroptosis inducers. Herein, we review recent progress in this evolving field, elucidating the numerous mechanisms by which mitochondria regulate ferroptosis and giving an insight into the role of the organelle in ferroptosis. Additionally, we present an overview of how mitochondria contribute to ferroptosis in malaria. Furthermore, we attempt to shed light on an inclusive perspective on how targeting malaria parasites' mitochondrion and attacking redox homeostasis is anticipated to induce ferroptosis-mediated antiparasitic effects.

The Role Played by Mitochondria in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) refers to an endocrine disorder syndrome that are correlated with multiple organs and systems. PCOS has an effect on women at all stages of their lives, and it has an incidence nearly ranging from 6% to 20% worldwide. Mitochondrial dysfunctions (e.g., oxidative stress, dynamic imbalance, and abnormal quality control system) have been identified in patients and animal models of PCOS, and the above processes may play a certain role in the development of PCOS and its associated complications. However, their specific pathogenic roles should be investigated in depth. In this review, recent studies on the mechanisms of action of mitochondrial dysfunction in PCOS and its associated clinical manifestations are summarized from the perspective of tissues and organs, and some studies on the treatment of the disease by improving mitochondrial function are reviewed to highlight key role of mitochondrial dysfunction in this syndrome.

The Mechanism of Pyroptosis and Its Application Prospect in Diabetic Wound Healing

Pyroptosis defines a form of pro-inflammatory-dependent programmed cell death triggered by gasdermin proteins, which creates cytoplasmic pores and promotes the activation and accumulation of immune cells by releasing several pro-inflammatory mediators and immunogenic substances upon cell rupture. Pyroptosis comprises canonical (mediated by Caspase-1) and non-canonical (mediated by Caspase-4/5/11) molecular signaling pathways. Numerous studies have explored the contributory roles of inflammasome and pyroptosis in the progression of multiple pathological conditions such as tumors, nerve injury, inflammatory diseases and metabolic disorders. Accumulating evidence indicates that the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome results in the activation of pyroptosis and inflammation. Current evidence suggests that pyroptosis-dependent cell death plays a progressive role in the development of diabetic complications including diabetic wound healing (DWH) and diabetic foot ulcers (DFUs). This review presents a brief overview of the molecular mechanisms underlying pyroptosis and addresses the current research on pyroptosis-dependent signaling pathways in the context of DWH. In this review, we also present some prospective therapeutic compounds/agents that can target pyroptotic signaling pathways, which may serve as new strategies for the effective treatment and management of diabetic wounds.

Extracellular vesicles of Weizmannia coagulans lilac-01 reduced cell death of primary microglia and increased mitochondrial content in dermal fibroblasts in vitro

We investigated the properties of extracellular vesicles from the probiotic Weizmannia coagulans lilac-01 (Lilac-01EVs). The phospholipids in the Lilac-01EV membrane were phosphatidylglycerol and mitochondria-specific cardiolipin. We found that applying Lilac-01EVs to primary rat microglia in vitro resulted in a reduction in primary microglial cell death (P < .05). Lilac-01EVs, which contain cardiolipin and phosphatidylglycerol, may have the potential to inhibit cell death in primary microglia. The addition of Lilac-01EVs to senescent human dermal fibroblasts suggested that Lilac-01 EVs increase the mitochondrial content without affecting their membrane potential in these cells.

Construction of a Label-Detection Integrated Visual Probe to Reveal the Double-Edged Sword Principle of Ferroptosis in Liver Injury

Ferroptosis has been confirmed as a potential mediator and an indicator of the severity of liver injury. Despite the fruitful results, there are still two deficiencies in the research on the association between ferroptosis and liver injury. First, iron ions are usually selected as the target bioanalyte, but its detection based on a fluorescent probe is interfered with by specific chemical reaction mechanisms, leading to low sensitivity and poor physiological stability. Second, more efforts were focused on the harmful effects of ferroptosis on liver injury and less involved in the therapeutic value of ferroptosis for liver injury. Hence, in this work, we proposed a new nonreactive analyte (mitochondrial viscosity) as an analysis marker, which can circumvent the challenges caused by specific reaction mechanisms of iron ions. Meanwhile, we constructed a novel label-detection integrated visual probe (VPF) to explore the feasibility of ferroptosis in the treatment of liver injury. As expected, we not only successfully traced the dynamic changes in mitochondrial viscosity but also visualized the changes in cell morphology during induced and inhibited ferroptosis. Conspicuously, this work revealed that liver injury can be alleviated by regulating ferroptosis, confirming the therapeutic value of ferroptosis in liver injury. In addition, a complex biological communication network between ferroptosis and liver injury was constructed by western blotting, providing an important theoretical mechanism for revealing their double-edged sword relationship. This study not only provides a new strategy for studying the complex relationship between ferroptosis and liver injury but also facilitates the future treatment of liver injury.

The pathogenesis and potential therapeutic targets in sepsis

Sepsis is defined as "a life-threatening organ dysfunction caused by dysregulated host systemic inflammatory and immune response to infection." At present, sepsis continues to pose a grave healthcare concern worldwide. Despite the use of supportive measures in treating traditional sepsis, such as intravenous fluids, vasoactive substances, and oxygen plus antibiotics to eradicate harmful pathogens, there is an ongoing increase in both the morbidity and mortality associated with sepsis during clinical interventions. Therefore, it is urgent to design specific pharmacologic agents for the treatment of sepsis and convert them into a novel targeted treatment strategy. Herein, we provide an overview of the molecular mechanisms that may be involved in sepsis, such as the inflammatory response, immune dysfunction, complement deactivation, mitochondrial damage, and endoplasmic reticulum stress. Additionally, we highlight important targets involved in sepsis-related regulatory mechanisms, including GSDMD, HMGB1, STING, and SQSTM1, among others. We summarize the latest advancements in potential therapeutic drugs that specifically target these signaling pathways and paramount targets, covering both preclinical studies and clinical trials. In addition, this review provides a detailed description of the crosstalk and function between signaling pathways and vital targets, which provides more opportunities for the clinical development of new treatments for sepsis.

Research progress on the mechanism of curcumin in cerebral ischemia/reperfusion injury: a narrative review

Cerebral ischemia/reperfusion (I/R) injury can result in different levels of cerebral impairment, and in severe cases, death. Curcumin, an essential bioactive component of turmeric, has a rich history as a traditional medicine for various ailments in numerous countries. Experimental and clinical research has established that curcumin offers a protective effect against cerebral I/R injury. Curcumin exerts its protective effects by acting on specific mechanisms such as antioxidant, anti-inflammatory, inhibition of ferroptosis and pyroptosis, protection of mitochondrial function and structure, reduction of excessive autophagy, and improvement of endoplasmic reticulum (ER) stress, which ultimately help to preserve the blood-brain barrier (BBB) and reducing apoptosis. There is currently a shortage of drugs undergoing clinical trials for the treatment of cerebral I/R injury, highlighting the pressing need for research and development of novel treatments to address this injury. The primary objective of this study is to establish a theoretical basis for future clinical applications of curcumin by delineating the mechanisms and protective effects of curcumin against cerebral I/R injury. Adapted with permission from [1].

The diversified role of mitochondria in ferroptosis in cancer

Ferroptosis is a form of regulated cell death induced by iron-dependent lipid peroxidation, and it has been studied extensively since its discovery in 2012. Induced by iron overload and ROS accumulation, ferroptosis is modulated by various cellular metabolic and signaling pathways. The GSH-GPX4 pathway, the FSP1-CoQ10 pathway, the GCH1-BH4 pathway, the DHODH-CoQH2 system and the sex hormones suppress ferroptosis. Mitochondrial iron metabolism regulates ferroptosis and mitochondria also undergo a morphological change during ferroptosis, these changes include increased membrane density and reduced mitochondrial cristae. Moreover, mitochondrial energy metabolism changes during ferroptosis, the increased oxidative phosphorylation and ATP production rates lead to a decrease in the glycolysis rate. In addition, excessive oxidative stress induces irreversible damage to mitochondria, diminishing organelle integrity. ROS production, mitochondrial membrane potential, mitochondrial fusion and fission, and mitophagy also function in ferroptosis. Notably, some ferroptosis inhibitors target mitochondria. Ferroptosis is a major mechanism for cell death associated with the progression of cancer. Metastasis-prone or metastatic cancer cells are more susceptible to ferroptosis. Inducing ferroptosis in tumor cells shows very promising potential for treating drug-resistant cancers. In this review, we present a brief retrospect of the discovery and the characteristics of ferroptosis, then we discuss the regulation of ferroptosis and highlight the unique role played by mitochondria in the ferroptosis of cancer cells. Furthermore, we explain how ferroptosis functions as a double-edged sword as well as novel therapies aimed at selectively manipulating cell death for cancer eradication.

Diversity and complexity of cell death: a historical review

Death is the inevitable fate of all living organisms, whether at the individual or cellular level. For a long time, cell death was believed to be an undesirable but unavoidable final outcome of nonfunctioning cells, as inflammation was inevitably triggered in response to damage. However, experimental evidence accumulated over the past few decades has revealed different types of cell death that are genetically programmed to eliminate unnecessary or severely damaged cells that may damage surrounding tissues. Several types of cell death, including apoptosis, necrosis, autophagic cell death, and lysosomal cell death, which are classified as programmed cell death, and pyroptosis, necroptosis, and NETosis, which are classified as inflammatory cell death, have been described over the years. Recently, several novel forms of cell death, namely, mitoptosis, paraptosis, immunogenic cell death, entosis, methuosis, parthanatos, ferroptosis, autosis, alkaliptosis, oxeiptosis, cuproptosis, and erebosis, have been discovered and advanced our understanding of cell death and its complexity. In this review, we provide a historical overview of the discovery and characterization of different forms of cell death and highlight their diversity and complexity. We also briefly discuss the regulatory mechanisms underlying each type of cell death and the implications of cell death in various physiological and pathological contexts. This review provides a comprehensive understanding of different mechanisms of cell death that can be leveraged to develop novel therapeutic strategies for various diseases.

Sevoflurane preconditioning improves neuroinflammation in cerebral ischemia/reperfusion induced rats through ROS-NLRP3 pathway

AIM

We aimed to study the influence of sevoflurane on the nucleotide-binding domain and Leucine-rich repeat protein 3 (NLRP3) pathways in rats with cerebral ischemia/reperfusion (I/R) injury.

METHODS

Sixty Sprague-Dawley rats were equally divided into five groups randomly: sham-operated, cerebral I/R, sevoflurane (Sevo), NLRP3 inhibitor-treated (MCC950), and sevoflurane and NLRP3 inducer-treated groups. Rats' neurological functions were assessed using Longa scoring after 24 h of reperfusion, after which they were sacrificed, and cerebral infarction area was determined by triphenyl tetrazolium chloride staining. Pathological changes in damaged portions were assessed using hematoxylin-eosin and Nissl staining, and cell apoptosis was detected by terminal-deoxynucleotidyl transferase-mediated nick end labeling staining. Interleukin 1 beta (IL-1β), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18), malondialdehyde (MDA), and superoxide dismutase (SOD) levels in brain tissues were determined using enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. Protein levels of NLRP3, caspase-1, and IL-1β were determined by western blot.

RESULTS

Neurological function scores, cerebral infarction areas, and neuronal apoptosis index were decreased in the Sevo and MCC950 groups than in the I/R group. IL-1β, TNF-α, IL-6, IL-18, NLRP3, caspase-1, and IL-1β levels decreased in the Sevo and MCC950 groups (p < 0.05). ROS and MDA levels increased, but SOD levels increased in the Sevo and MCC950 groups than in the I/R group. NLPR3-inducer nigericin eliminated the protective effects of sevoflurane on cerebral I/R injury in rats.

CONCLUSION

Sevoflurane could alleviate cerebral I/R-induced brain damage by inhibiting the ROS-NLRP3 pathway.

Dexpramipexole ameliorates cognitive deficits in sepsis-associated encephalopathy through suppressing mitochondria-mediated pyroptosis and apoptosis

OBJECTIVES

This study was aimed at evaluating the effects of dexpramipexole (DPX) - a mitochondrial protectant that sustains mitochondrial function and energy production - on cognitive function in a mouse model of sepsis-associated encephalopathy (SAE) induced by peripheral administration of lipopolysaccharide (LPS) and examining the potential mechanisms.

METHODS

C57BL/6 male mice were randomized into one of four treatment protocols: Con+Sal, Con+DPX, LPS+Sal or LPS+DPX. The mice were intraperitoneally (i.p.) injected with LPS or equivalent volumes of normal saline once daily for 3 consecutive days. To evaluate the protective effects of DPX, we administered DPX or normal saline i.p. to the mice once daily for 6 consecutive days. Six mice in each group were decapitated on day 7, and each brain was rapidly removed and separated into two halves for biochemical and histochemical analysis. The remaining surviving mice in each group were subjected to behavioral tests from days 7 to 10.

RESULTS

Peripheral administration of LPS to mice led to learning and memory deficits in behavioral tests, which were associated with mitochondrial impairment and ATP depletion in the hippocampus. Repeated DPX treatment protected the mitochondria against LPS-induced morphological and functional impairment; inhibited the activation of the Nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome-caspase-1-dependent pyroptosis pathway and cytochrome c (Cyt-c)-caspase-3-dependent apoptosis pathway; and attenuated LPS-induced neuroinflammation and cell death in the hippocampus in SAE mice.

CONCLUSIONS

Mitochondria-mediated pyroptosis and apoptosis are involved in the pathogenesis of cognitive deficits in a mouse model of SAE and DPX protects mitochondria and suppresses the mitochondria-medicated pyroptosis and apoptosis pathways, and ameliorates LPS-induced neuroinflammation and cognitive deficits. This study provides theoretical evidence supporting DPX for the treatment of SAE.

A RIPK3-independent role of MLKL in suppressing parthanatos promotes immune evasion in hepatocellular carcinoma

Mixed lineage kinase domain-like (MLKL) is widely accepted as an executioner of necroptosis, in which MLKL mediates necroptotic signaling and triggers cell death in a receptor-interacting protein kinase 3 (RIPK3)-dependent manner. Recently, it is increasingly noted that RIPK3 is intrinsically silenced in hepatocytes, raising a question about the role of MLKL in hepatocellular carcinoma (HCC). This study reports a previously unrecognized role of MLKL in regulating parthanatos, a programmed cell death distinct from necroptosis. In HCC cells with intrinsic RIPK3 deficiency, knockout of MLKL impedes the orthotopic tumor growth, activates the anti-tumor immune response and enhances the therapeutic effect of immune checkpoint blockade in syngeneic HCC tumor models. Mechanistically, MLKL is required for maintaining the endoplasmic reticulum (ER)-mitochondrial Mg²⁺ dynamics in HCC cells. MLKL deficiency restricts ER Mg²⁺ release and mitochondrial Mg²⁺ uptake, leading to ER dysfunction and mitochondrial oxidative stress, which together confer increased susceptibility to metabolic stress-induced parthanatos. Importantly, pharmacological inhibition of poly(ADP-ribose) polymerase to block parthanatos restores the tumor growth and immune evasion in MLKL-knockout HCC tumors. Together, our data demonstrate a new RIPK3-independent role of MLKL in regulating parthanatos and highlight the role of MLKL in facilitating immune evasion in HCC.

The Role of Pyroptosis and Autophagy in Ischemia Reperfusion Injury

Pyroptosis is a process of programmed cell death mediated by gasdermin (GSDM) found in recent years. In the process of pyroptosis, caspase-1 or caspase-11/4/5 is activated, which cleaves gasdermin D and separates its N-terminal pore-forming domain (PFD). The oligomers of PFD bind to the cell membrane and form macropores on the membrane, resulting in cell swelling and membrane rupture. Increasing evidence indicates that pyroptosis is involved in many diseases, including ischemia reperfusion injury. Autophagy is a highly conserved catabolic process in eukaryotic cells. It plays an important role in the survival and maintenance of cells by degrading organelles, proteins, and macromolecules in the cytoplasm and recycling degradation products. Increasing evidence shows that dysfunctional autophagy participates in many diseases. Recently, autophagy and pyroptosis have been reported to play a vital role in the process of ischemia/reperfusion injury, but the related mechanisms are not completely clear. Therefore, this article reviews the role of autophagy and pyroptosis in ischemia–reperfusion injury and analyzes the related mechanisms to provide a basis for future research.

Germacrone induces caspase-3/GSDME activation and enhances ROS production, causing HepG2 pyroptosis

Liver cancer is a highly lethal malignancy. Despite considerable efforts made in recent years, the prognosis of patients with liver cancer remains poor. Curcuma zedoaria (known as Ezhu in Chinese) is widely prescribed in traditional Chinese medicine. Germacrone (GM) is a sesquiterpene constituent derived from the essential oil of Ezhu, and exerts anti-carcinogenic effects by inducing apoptosis in various cancer cells. The present study investigated the potential mechanism of GM in HepG2 cells. Cell Counting Kit-8, colony-formation and lactate dehydrogenase-release assays, as well as cell death assays using flow cytometry, were performed to evaluate HepG2 cell proliferation following GM treatment. HepG2 cells were transfected with caspase-3 small interfering RNA and then treated with GM. Caspase-3 expression levels were determined by reverse transcription-quantitative PCR and western blotting. The present study showed that GM inhibited the growth of HepG2 cells and induced the proteolytic cleavage of caspase 3, with concomitant cleavage of gasdermin E (GSDME), by markedly increasing the production of reactive oxygen species (ROS). This led to caspase 3-dependent cleavage of GSDME, thereby promoting pyroptosis in HepG2 cells. However, these changes were rescued by ROS scavengers, such as N-acetylcysteine. Furthermore, GM inhibited tumor growth by promoting the cleavage of caspase 3 and GSDME in HepG2 cell xenograft models. These results indicated that GM induced GSDME-dependent pyroptosis through caspase 3 activation, at least in part, by damaging the mitochondria and enhancing ROS production, thereby supporting the possible development of GM as a candidate for the prevention and treatment of liver cancer.

Programmed Cell Death Tunes Tumor Immunity

The demise of cells in various ways enables the body to clear unwanted cells. Studies over the years revealed distinctive molecular mechanisms and functional consequences of several key cell death pathways. Currently, the most intensively investigated programmed cell death (PCD) includes apoptosis, necroptosis, pyroptosis, ferroptosis, PANoptosis, and autophagy, which has been discovered to play crucial roles in modulating the immunosuppressive tumor microenvironment (TME) and determining clinical outcomes of the cancer therapeutic approaches. PCD can play dual roles, either pro-tumor or anti-tumor, partly depending on the intracellular contents released during the process. PCD also regulates the enrichment of effector or regulatory immune cells, thus participating in fine-tuning the anti-tumor immunity in the TME. In this review, we focused primarily on apoptosis, necroptosis, pyroptosis, ferroptosis, PANoptosis, and autophagy, discussed the released molecular messengers participating in regulating their intricate crosstalk with the immune response in the TME, and explored the immunological consequence of PCD and its implications in future cancer therapy developments.

Pyroptosis in neurodegenerative diseases: What lies beneath the tip of the iceberg?

Neurodegenerative diseases gradually receive attention with a rapidly aging global population. The hallmark of them is a progressive neuronal loss in the brain or peripheral nervous system due to complex reasons ranging from protein aggregation, immune dysregulation to abnormal cell death. The death style of nerve cell is no longer restricted to apoptosis, autophagy and necrosis as confirmed before. With the successive discoveries of the gasdermin (GSDM) protein family and key caspase molecules in the past several decades, pyroptosis emerges as a novel kind of programmed cell death. A substantial body of evidence has recognized the close connection between pyroptosis and the occurrence and development of neurodegenerative diseases. In this review, we summarize molecular mechanisms of pyroptosis, evidences for pyroptosis involvement in neurodegenerative diseases and finally we hope to provide a novel angle for clinical decision-making.

Nrf2 Inhibits the Progression of Parkinson’s Disease by Upregulating AABR07032261.5 to Repress Pyroptosis

Objective

Parkinson’s disease (PD) is associated with dysregulated neural cell death, such as pyroptosis, but its regulatory mechanisms are poorly understood. This study investigated roles of nuclear factor E2-related factor 2 (Nrf2) in regulating pyroptosis and PD development.

Methods

Cellular and rat PD models established by 6-OHDA exposure were subjected to Nrf2 overexpression. Neurobehavioral functions were assessed by the traction test, Morris Water Maze, and open field test. Cell proliferation was analyzed by MTS assay, while flow cytometry was applied to quantify levels of reactive oxygen species (ROS) and apoptosis. Nissl bodies in rat brains were detected by Nissl staining, and cell apoptosis in brain tissues was assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling. Differential expression of lncRNA and mRNA was characterized by deep sequencing.

Results

A cellular PD model was successfully established by inducing PC12 cell differentiation with nerve growth factor-β and exposing differentiated cells to 6-OHDA. Cells exhibited significantly increased ROS levels, enhanced pyroptosis, and inhibited Nrf2 phosphorylation. The rat PD model exhibited impaired muscle strength, increased pyroptosis, and repressed Nrf2 phosphorylation. Nrf2 overexpression effectively repressed pyroptosis in both cellular and rat PD models. Marked alterations of lncRNA and mRNA profiles were induced by Nrf2 overexpression in the cellular PD model, which involved multiple signaling pathways. Silencing of the lncRNA AABR07032261.5 significantly promoted pyroptosis in the cellular PD model.

Conclusion

Nrf2 suppressed PD pathogenesis in cellular and animal models by promoting AABR07032261.5, which repressed pyroptosis.

Quercetin Inhibits Pyroptosis in Diabetic Cardiomyopathy through the Nrf2 Pathway

The present study investigated whether quercetin promotes the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) to inhibit pyroptosis progression and ameliorate diabetic cardiomyopathy. We evaluated the protective effects of quercetin against diabetic cardiomyopathy by analyzing the expression of pyroptosis pathway proteins, myocardial cell apoptosis rate, degree of myocardial fibrosis, and serum inflammatory indices in the hearts of model rats with diabetes. We evaluated the expression of Nrf2 in the nucleus of cardiomyocytes and H9C2 cells to clarify the role of quercetin in promoting the nuclear translocation of Nrf2. In addition, we coincubated cardiomyocytes with the Nrf2 inhibitor ML385 to confirm that quercetin inhibits the diabetes-induced cardiomyocyte pyroptosis via the Nrf2 pathway. We found that quercetin promoted the nuclear translocation of Nrf2 in cardiac cells of diabetic rats, increased the expression of the antioxidant proteins HO-1, GCLC, and SOD, reduced the accumulation of ROS and the degree of cardiomyocyte apoptosis, and alleviated diabetes-induced cardiac fibrosis. The therapeutic effects of quercetin were further validated in H9C2 cardiomyocytes. Interestingly, ML385 prevented the beneficial effects of quercetin on diabetic cardiomyopathy, further indicating that the quercetin-mediated inhibition of pyroptosis requires the participation of the Nrf2 pathway. In conclusion, quercetin promoted the nuclear translocation of Nrf2, increased the expression of antioxidant factors in cells, and inhibited the progression of cell pyroptosis, thereby alleviating diabetic cardiomyopathy.

Methods for monitoring cancer cell pyroptosis

Pyroptosis is a form of proinflammatory cell death that depends on the gasdermin family of proteins. The main features of pyroptosis are altered membrane permeability, cell swelling, membrane rupture, and the ability to mobilize a strong immune response. The relationship between pyroptosis and cancer has become a popular topic in immunological research. Multiple strategies for inducing pyroptosis in cancer cells have been developed for cancer therapy, including chemotherapy, small molecule drugs, and nanomedicines. In this review, we systematically discuss recent advances in research on the mechanisms of pyroptosis, and compare pyroptosis with apoptosis and necroptosis from several aspects. The development of various experimental systems has accompanied rapid progress in this field, but little consensus on monitoring pyroptosis is currently available. We focus on techniques commonly used to monitor pyroptosis, and describe future techniques that may be used to increase our knowledge in this field. Overall, the advancement of pyroptosis detection methods will help researchers to better investigate the relationships between pyroptosis and various cancers, and should provide insights into the use of these promising tools for cancer treatments.

Mitochondria in Injury, Inflammation and Disease of Articular Skeletal Joints

Inflammation is an important biological response to tissue damage caused by injury, with a crucial role in initiating and controlling the healing process. However, dysregulation of the process can also be a major contributor to tissue damage. Related to this, although mitochondria are typically thought of in terms of energy production, it has recently become clear that these important organelles also orchestrate the inflammatory response via multiple mechanisms. Dysregulated inflammation is a well-recognised problem in skeletal joint diseases, such as rheumatoid arthritis. Interestingly osteoarthritis (OA), despite traditionally being known as a ‘non-inflammatory arthritis’, now appears to involve an element of chronic inflammation. OA is considered an umbrella term for a family of diseases stemming from a range of aetiologies (age, obesity etc.), but all with a common presentation. One particular OA sub-set called Post-Traumatic OA (PTOA) results from acute mechanical injury to the joint. Whether the initial mechanical tissue damage, or the subsequent inflammatory response drives disease, is currently unclear. In the former case; mechanobiological properties of cells/tissues in the joint are a crucial consideration. Many such cell-types have been shown to be exquisitely sensitive to their mechanical environment, which can alter their mitochondrial and cellular function. For example, in bone and cartilage cells fluid-flow induced shear stresses can modulate cytoskeletal dynamics and gene expression profiles. More recently, immune cells were shown to be highly sensitive to hydrostatic pressure. In each of these cases mitochondria were central to these responses. In terms of acute inflammation, mitochondria may have a pivotal role in linking joint tissue injury with chronic disease. These processes could involve the immune cells recruited to the joint, native/resident joint cells that have been damaged, or both. Taken together, these observations suggest that mitochondria are likely to play an important role in linking acute joint tissue injury, inflammation, and long-term chronic joint degeneration - and that the process involves mechanobiological factors. In this review, we will explore the links between mechanobiology, mitochondrial function, inflammation/tissue-damage in joint injury and disease. We will also explore some emerging mitochondrial therapeutics and their potential for application in PTOA.

Verification of ferroptosis and pyroptosis and identification of PTGS2 as the hub gene in human coronary artery atherosclerosis

Ferroptosis and pyroptosis have not been fully studied in atherosclerosis. We aimed to investigate the expression of ferroptosis-related and pyroptosis-related proteins in human coronary arteries and analyse correlation with severity of atherosclerosis and clarify the interactions between proteins and possible mechanisms of atherosclerosis. 40 human coronary artery specimens were employed. The atherosclerotic lesions were characterized by Haematoxylin and Eosin (H&E) staining. The expression of prostaglandin-endoperoxide synthase 2 (PTGS2), anti-acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), caspase-1, and NOD-like receptor protein 3 (NLRP3) were analysed by immunohistochemical assay. Correlations between expression of proteins and severity of atherosclerosis were assessed using Spearman correlation analysis. Bioinformatic and coexpression analyses were performed to study the possible pathways and interactions. In the present study, PTGS2, ACSL4, caspase-1, and NLRP3, were upregulated, while GPX4 was downregulated in the advanced stages of atherosclerosis. The severity of atherosclerosis was positively associated with the expression of PTGS2, ACSL4, caspase-1, and NLRP3 and negatively associated with the expression of GPX4. Biological processes of lipid metabolism and inflammation and C-type lectin receptor signaling pathway were enriched. The five proteins interacted with each other directly or indirectly and PTGS2 might be the hub gene of atherosclerosis. Ferroptosis and pyroptosis may regulate the occurrence and development of atherosclerosis. These findings may shed light on new ideas and potential targets for the prevention and treatment of coronary artery atherosclerosis and the proteins may be used as biomarkers for the severity of atherosclerosis.