GSDMD in peripheral myeloid cells regulates microglial immune training and neuroinflammation in Parkinson's disease

Inhibiting ceramide synthase 5 expression in microglia decreases neuroinflammation after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202510000-00026/figure1/v/2024-11-26T163120Z/r/image-tiff Microglia, the resident monocyte of the central nervous system, play a crucial role in the response to spinal cord injury. However, the precise mechanism remains unclear. To investigate the molecular mechanisms by which microglia regulate the neuroinflammatory response to spinal cord injury, we performed single-cell RNA sequencing dataset analysis, focusing on changes in microglial subpopulations. We found that the MG1 subpopulation emerged in the acute/subacute phase of spinal cord injury and expressed genes related to cell pyroptosis, sphingomyelin metabolism, and neuroinflammation at high levels. Subsequently, we established a mouse model of contusive injury and performed intrathecal injection of siRNA and molecular inhibitors to validate the role of ceramide synthase 5 in the neuroinflammatory responses and pyroptosis after spinal cord injury. Finally, we established a PC12-BV2 cell co-culture system and found that ceramide synthase 5 and pyroptosis-associated proteins were highly expressed to induce the apoptosis of neuron cells. Inhibiting ceramide synthase 5 expression in a mouse model of spinal cord injury effectively reduced pyroptosis. Furthermore, ceramide synthase 5-induced pyroptosis was dependent on activation of the NLRP3 signaling pathway. Inhibiting ceramide synthase 5 expression in microglia in vivo reduced neuronal apoptosis and promoted recovery of neurological function. Pla2g7 formed a "bridge" between sphingolipid metabolism and ceramide synthase 5-mediated cell death by inhibiting the NLRP3 signaling pathway. Collectively, these findings suggest that inhibiting ceramide synthase 5 expression in microglia after spinal cord injury effectively suppressed microglial pyroptosis mediated by NLRP3, thereby exerting neuroprotective effects.

Astrocyte-derived CCL5-mediated CCR5+ neutrophil infiltration drives depression pathogenesis

Cross-talk between the nervous and immune systems is involved in neurological diseases. However, their potential interplay in depression has yet to be elucidated. Here, using single-cell RNA and neutrophil SMART RNA sequencing, we showed that CCR5+ neutrophils were significantly increased in patients with depression and preferentially migrated to the hippocampus in a mouse model of depression. Infiltrated neutrophils engulf neuronal spines and subsequently promote depressive symptoms in male mice. Furthermore, by genetic or pharmacologic disruption, we identified a chemotactic effect of the astrocyte-derived chemokine CCL5 on mediating the infiltration of CCR5+ neutrophils and behavioral disorders in male depressed mice. Our findings therefore highlight the critical role of neutrophils in depression pathogenesis and astrocytes in mediating the dysregulation of innate immune responses and suggest that inhibition of CCL5/CCR5-mediated neutrophil infiltration represents a potential therapeutic strategy for noninfectious brain diseases such as depression.

GL-V9 inhibits Caspase-11 activation-induced pyroptosis by suppressing ALOX12-mediated lipid peroxidation to alleviate sepsis

BACKGROUND AND PURPOSE

Sepsis, caused by pathogen infection, poses a serious threat to human life. While the link between sepsis and pyroptosis via Caspase-11 non-canonical inflammasome activation is known, effective treatments remain lacking. Previous studies have confirmed that GL-V9 has antifibrotic and antitumor activities, but whether it has a therapeutic effect on sepsis is unclear. The aim of this study was to investigate the anti-inflammatory activity of GL-V9 and its possible mechanism.

EXPERIMENTAL APPROACH

The caecal ligation and puncture (CLP) model was used to assess the antiseptic effects of GL-V9 in vivo. Mouse bone marrow derived macrophages (BMDMs) and murine macrophages line J774A.1 also served as an in vitro Caspase-11 activation induced pyroptosis model. Cellular functions and molecular mechanism were analysed using cell viability assay, PI uptake assay, western blotting, immunofluorescence and co-immunoprecipitation.

KEY RESULTS

GL-V9 reduced tissue damage and mortality in mice with sepsis, and decreased the secretion of inflammatory factors in vivo. In vitro, GL-V9 suppressed Caspase-11-induced pyroptosis and prevented the release of LPS from early endosomes. Mechanistic studies revealed that GL-V9 limits Caspase-11 activation by inhibiting ALOX12-mediated lipid peroxidation. Further studies confirmed that GL-V9 did not further alleviate the symptoms and inflammatory response of septic mice in Alox12 deficient mice.

CONCLUSION AND IMPLICATIONS

GL-V9 exerts a powerful anti-sepsis effect in vivo, which is associated with the inhibition of Caspase-11 activation. Mechanistically, GL-V9 may block LPS release from early endosomes by inhibiting ALOX12-mediated lipid peroxidation. This suggests that GL-V9 is a potential candidate for the treatment of sepsis.

Glucose Metabolic Reprogramming in Microglia: Implications for Neurodegenerative Diseases and Targeted Therapy

As intrinsic immune cells in the central nervous system, microglia play a crucial role in maintaining brain homeostasis. Microglia can transition from homeostasis to various responsive states in reaction to different external stimuli, undergoing corresponding alterations in glucose metabolism. In neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), microglial glucose metabolic reprogramming is widespread. This reprogramming leads to changes in microglial function, exacerbating neuroinflammation and the accumulation of pathological products, thereby driving the progression of neurodegeneration. This review summarizes the specific alterations in glucose metabolism within microglia in AD, PD, ALS, and MS, as well as the corresponding treatments aimed at reprogramming glucose metabolism. Compounds that inhibit key glycolytic enzymes like hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2), or activate regulators of energy metabolism such as AMP-activated protein kinase (AMPK), have shown significant potential in the treatment of various neurodegenerative diseases. However, current research faces numerous challenges, including side effects and blood-brain barrier (BBB) penetration of compounds. Screening relevant drugs from natural products, especially flavonoids, is a reliable approach. On the one hand, longtime herbal medical practices provide a certain degree of assurance regarding clinical safety, and their chemical properties contribute to effective BBB permeability. On the other hand, the concurrent anti-tumor and anti-neuroinflammatory activities of flavonoids suggest that regulation of glucose metabolism reprogramming might be a potential common mechanism of action. Notably, considering the dynamic nature of microglial metabolism, there is an urgent need to develop technologies for real-time monitoring of glucose metabolism processes, which would significantly advance research in this field.

Wolfberry (Lycium barbarum) glycopeptide attenuates dopaminergic neurons loss by inhibiting lipid peroxidation in Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disorder characterized clinically by motor dysfunction due to gradual loss of dopaminergic neurons in the nigrostriatal system. Currently, medications such as levodopa preparations, offer only temporary symptomatic relief without preventing neuronal loss or halting disease progression. In traditional Chinese medicine (TCM), a particular type of wolfberry or goji berry, the fruit of Lycium barbarum L., has been historically regarded for its neuroprotective properties, potentially offering therapeutic benefits for PD. However, scientific validation of these effects remains limited.

PURPOSE

This study aims to investigate the neuroprotective effects of wolfberry glycopeptide (WGP) on PD progression in various animal models, and to elucidate the underlying mechanisms responsible for its therapeutic action.

STUDY DESIGN

Diverse canonical animal models, including 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, 6-hydroxydopamine (6-OHDA)-treated rats, and α-synuclein overexpressed hSNCAA53T mice, were used to evaluate WGP's anti-PD efficacy. Behavioral deficits and pathological damage to dopaminergic neurons were assessed to determine WGP's neuroprotective potential.

METHODS

After establishing the animal models and administering WGP treatment, PD-like behaviors were assessed using pole test, rotarod test and gait analysis. Dopaminergic neurons loss in the midbrain and striatum was detected by means of immunohistochemistry, immunofluorescence and Western blot analysis. Inflammatory markers in these brain regions were measured by ELISA.

RESULTS

WGP treatment significantly alleviated motor deficits as well as progressive dopaminergic neurons loss. Mechanistically, WGP exerted its neuroprotective effects by regulating iron homeostasis, specifically through the modulation of key proteins such as TFRC, FTH1, and FPN. This function contributed to reducing the accumulation of lipid peroxidation in nigrostriatal system, thereby mitigating neuroinflammation and neuronal degeneration.

CONCLUSION

Our findings underscore the innovative potential of WGP as a neuroprotective agent in PD, with a unique mechanism of action targeting iron homeostasis and lipid peroxidation-driven neurodegeneration. This study advances the understanding of TCM's therapeutic contributions to neurodegeneration and positions WGP as a strong candidate for further clinical development in PD treatment.

Identification of two repurposed drugs targeting GSDMD oligomerization interface I to block pyroptosis

As an executor of pyroptosis, gasdermin D (GSDMD) plays a critical role in inflammatory diseases and cancer. Thus, GSDMD is currently being widely explored as a drug target. Existing inhibitors targeting GSDMD, such as necrosulfonamide, disulfiram, and fumarate, primarily prevent pyroptosis by modifying human/mouse C191/C192 in the N-terminal fragment of GSDMD. However, cysteine modification can prevent the function of important proteins or enzymes, thereby leading to adverse reactions. Here, we chose an alternative key intervention site for GSDMD activation, which is located at the oligomerization interface I of its pore-forming structure. Through high-throughput virtual and experimental screening and in combination with efficacy and pharmacological validation, we have identified two safe, specific "repurposed drugs" that potently suppress GSDMD-mediated pyroptosis. Moreover, the candidates exhibited synergistic therapeutic effects of "1 + 1>2" in murine sepsis and tumorigenesis models. These recently identified GSDMD inhibitors hold great promise for clinical translation in the development of anti-inflammatory and anti-cancer immunotherapies.

Neuroinflammation in Age-Related Neurodegenerative Diseases: Role of Mitochondrial Oxidative Stress

A shared hallmark of age-related neurodegenerative diseases is the chronic activation of innate immune cells, which actively contributes to the neurodegenerative process. In Alzheimer's disease, this inflammatory milieu exacerbates both amyloid and tau pathology. A similar abnormal inflammatory response has been reported in Parkinson's disease, with elevated levels of cytokines and other inflammatory intermediates derived from activated glial cells, which promote the progressive loss of nigral dopaminergic neurons. Understanding the causes that support this aberrant inflammatory response has become a topic of growing interest and research in neurodegeneration, with high translational potential. It has been postulated that the phenotypic shift of immune cells towards a proinflammatory state combined with the presence of immunogenic cell death fuels a vicious cycle in which mitochondrial dysfunction plays a central role. Mitochondria and mitochondria-generated reactive oxygen species are downstream effectors of different inflammatory signaling pathways, including inflammasomes. Dysfunctional mitochondria are also recognized as important producers of damage-associated molecular patterns, which can amplify the immune response. Here, we review the major findings highlighting the role of mitochondria as a checkpoint of neuroinflammation and immunogenic cell deaths in neurodegenerative diseases. The knowledge of these processes may help to find new druggable targets to modulate the inflammatory response.

Myeloid gasdermin D drives early-stage T cell immunity and peripheral inflammation in a mouse model of Alzheimer's disease

BACKGROUND

It is now realized that peripheral inflammation and abnormal immune responses, especially T cells, contribute to the development of Alzheimer's disease (AD). Gasdermin D (GSDMD) -mediated pyroptosis has been associated with several neuroinflammatory diseases, but whether GSDMD is involved in the peripheral inflammation and T cell immunity during AD remains unclear.

METHODS

We dynamically investigated GSDMD activation in the peripheral and central nervous system of 5×FAD mouse model and dissected the role of myeloid GSDMD using genetic knockout mice, especially its influence on peripheral T cell responses and AD inflammation. RNA sequencing and in vitro coculture were used to elucidate the underlying immune mechanisms involved. Targeted inhibitor experiments and clinical correlation analysis were used to further verify the function of GSDMD in AD.

RESULTS

In the present study, caspase activated GSDMD in the spleen of 5×FAD mice earlier than in the brain during disease progression. Loss of myeloid cell GSDMD was shown to impair early-stage effector T cell activation in the periphery and prevent T cell infiltration into the brain, with an overall reduction in neuroinflammation. Furthermore, myeloid cell GSDMD induced T cell PD-1 expression through the IL-1β/NF-κB pathway, restricting regulatory T cells. The administration of a GSDMD inhibitor combined with an anti-PD-1 antibody was found to mitigate the development of AD-associated inflammation. In some AD patients, plasma sPD-1 is positively correlated with IL-Iβ and clinical features.

CONCLUSIONS

Our study systematically identified a role for GSDMD in the AD-related peripheral inflammation and early-stage T cell immunity. These findings also suggest the therapeutic potential of targeting GSDMD for the early intervention in AD.

Pyroptosis: Induction and inhibition strategies for immunotherapy of diseases

Cell death is a central process for organismal health. Pyroptosis, namely pyroptotic cell death, is recognized as a critical type that disrupts membrane and triggers pro-inflammatory cytokine secretion via gasdermins, providing a robust form of cytolysis. Meanwhile, along with the thorough research, a great deal of evidence has demonstrated the dual effects of pyroptosis in host defense and inflammatory diseases. More importantly, the recent identification of abundant gasdermin-like proteins in bacteria and fungi suggests an ancient origin of pyroptosis-based regulated cell death in the life evolution. In this review, we bring a general overview of pyroptosis pathways focusing on gasdermin structural biology, regulatory mechanisms, and recent progress in induction and inhibition strategies for disease treatment. We look forward to providing an insightful perspective for readers to comprehend the frame and challenges of the pyroptosis field, and to accelerating its clinical application.

"Glycans in Trained Immunity: Educators of innate immune memory in homeostasis and disease"

Trained Immunity is defined as a biological process normally induced by exogenous or endogenous insults that triggers epigenetic and metabolic reprogramming events associated with long-term adaptation of innate immune cells. This trained phenotype confers enhanced responsiveness to subsequent triggers, resulting in an innate immune "memory" effect. Trained Immunity, in the past decade, has revealed important benefits for host defense and homeostasis, but can also induce potentially harmful outcomes associated with chronic inflammatory disorders or autoimmune diseases. Interestingly, evidence suggest that the "trainers" prompting trained immunity are frequently glycans structures. In fact, the exposure of different types of glycans at the surface of pathogens is a key driver of the training phenotype, leading to the reprogramming of innate immune cells through the recognition of those glycan-triggers by a variety of glycan-binding proteins (GBPs) expressed by the immune cells. β-glucan or mannose-enriched structures in Candida albicans are some of the examples that highlight the potential of glycans in trained immunity, both in homeostasis and in disease. In this review, we will discuss the relevance of glycans exposed by pathogens in establishing key immunological hubs with glycan-recognizing receptors expressed in immune cells, highlighting how this glycan-GBP network can impact trained immunity. Finally, we discuss the power of glycans and GBPs as potential targets in trained immunity, envisioning potential therapeutic applications.

NLRP3 inflammasome activation and pyroptosis are dispensable for tau pathology

Background

Neuroinflammation is widely recognized as a key factor in the pathogenesis of Alzheimer's disease (AD), alongside ß-amyloid deposition and the formation of neurofibrillary tangles. The NLR family pyrin domain containing 3 (NLRP3) inflammasome, part of the innate immune system, has been implicated in the neuropathology of both preclinical amyloid and tau transgenic models. Activation of the NLRP3 pathway involves an initial priming step, which increases the expression of Nlrp3 and interleukin (IL)-1β, followed by the assembly of the NLRP3 inflammasome complex, comprising NLRP3, ASC, and caspase-1. This assembly leads to the proteolytic maturation of the pro-inflammatory cytokines IL-1β and IL-18. Additionally, the NLRP3 inflammasome induces Gasdermin D (GSDMD) cleavage, forming membrane pores through which IL-1β and IL-18 are secreted. Inhibition of NLRP3 has been shown to enhance plaque clearance by modulating microglial activation. Furthermore, blocking NLRP3 in tau transgenic mice has been found to reduce tau phosphorylation by affecting the activity of certain tau kinases and phosphatases.

Methods

In this study, organotypic brain slice cultures from P301S transgenic mice were treated with lipopolysaccharide (LPS) plus nigericin as a positive control or exposed to tau seeds (K18) to evaluate NLRP3 inflammasome activation. The effect of tau seeding on NLRP3 activity was further examined using Meso Scale Discovery (MSD) assays to measure IL1β secretion levels in the presence and absence of NLRP3 inhibitors. The role of NLRP3 activity was investigated in full-body Nlrp3 knockout mice crossbred with the tau transgenic P301S model. Additionally, full-body and microglia-selective Gsdmd knockout mice were crossbred with P301S mice, and tau pathology and neurodegeneration were evaluated at early and late stages of the disease using immunohistochemistry and biochemical assays.

Results

Activation of the NLRP3 pathway was observed in the mouse organotypic slice culture (OSC) model following stimulation with LPS and nigericin or exposure to tau seeds. However, Nlrp3 deficiency did not mitigate tauopathy or neurodegeneration in P301S mice in vivo, showing only a minor effect on plasma neurofilament (NF-L) levels. Consistently, Gsdmd deficiency did not alter tau pathology in P301S mice. Furthermore, neither full-body nor microglia-selective Gsdmd deletion had an impact on neuronal pathology or the release of pro-inflammatory cytokines.

Conclusion

The absence of key components of the NLRP3 inflammasome pathway did not yield a beneficial effect on tau pathology or neurodegeneration in the preclinical Tau-P301S mouse model of AD. Nonetheless, organotypic slice cultures could serve as a valuable ex vivo mechanistic model for evaluating NLRP3 pathway activation and pharmacological inhibitors.

Mitophagy and cGAS-STING crosstalk in neuroinflammation

Mitophagy, essential for mitochondrial health, selectively degrades damaged mitochondria. It is intricately linked to the cGAS-STING pathway, which is crucial for innate immunity. This pathway responds to mitochondrial DNA and is associated with cellular stress response. Our review explores the molecular details and regulatory mechanisms of mitophagy and the cGAS-STING pathway. We critically evaluate the literature demonstrating how dysfunctional mitophagy leads to neuroinflammatory conditions, primarily through the accumulation of damaged mitochondria, which activates the cGAS-STING pathway. This activation prompts the production of pro-inflammatory cytokines, exacerbating neuroinflammation. This review emphasizes the interaction between mitophagy and the cGAS-STING pathways. Effective mitophagy may suppress the cGAS-STING pathway, offering protection against neuroinflammation. Conversely, impaired mitophagy may activate the cGAS-STING pathway, leading to chronic neuroinflammation. Additionally, we explored how this interaction influences neurodegenerative disorders, suggesting a common mechanism underlying these diseases. In conclusion, there is a need for additional targeted research to unravel the complexities of mitophagy-cGAS-STING interactions and their role in neurodegeneration. This review highlights potential therapies targeting these pathways, potentially leading to new treatments for neuroinflammatory and neurodegenerative conditions. This synthesis enhances our understanding of the cellular and molecular foundations of neuroinflammation and opens new therapeutic avenues for neurodegenerative disease research.

GSDMD protects intestinal epithelial cells against bacterial infections through its N-terminal activity impacting intestinal immune homeostasis

The intestinal mucosal barrier serves as a vital guardian for gut health, maintaining a delicate equilibrium between gut microbiota and host immune homeostasis. Recent studies have found the intricate roles of Gasdermin D (GSDMD), a key executioner of pyroptosis downstream of the inflammasome, within the intestine, including controlling colitis in intestinal macrophage and the regulatory function in goblet cell mucus secretion. Thus, the exact role and nature of GSDMD's regulatory function in maintaining intestinal immune homeostasis and defending against pathogens remain elucidation. Here, we uncover that GSDMD plays a key role in defending against intestinal Citrobacter rodentium infection, with high expression in intestinal epithelial and lamina propria myeloid cells. Our results show that GSDMD specifically acts in intestinal epithelial cells to fight the infection, independently of its effects on antimicrobial peptides or mucin secretion. Instead, the resistance is mediated through GSDMD's N-terminal fragments, highlighting its importance in intestinal immunity. However, the specific underlying mechanism of GSDMD N-terminal activity in protection against intestinal bacterial infections still needs further study to clarify in the future.

Causal role of myeloid cells in Parkinson's disease: Mendelian randomization study

BACKGROUND

Previous studies have observed elevated myeloid cells in the peripheral blood of patients with Parkinson's disease (PD), but the causal relationship between them remains to be elucidated. We investigated whether there is a causal relationship between different subtypes of peripheral blood myeloid cells and PD using Mendelian randomization (MR) combined with bioinformatics analysis. Exploring the etiology of PD from the perspective of genetics can remove confounding factors and provide a more reliable theoretical basis for elucidating the pathogenesis of PD.

METHODS

Comprehensive two-sample MR analysis and sensitivity analyses were conducted to explore the causal associations between 64 myeloid cell signatures and PD risk. The Venn diagram and protein-protein interaction network analysis of instrumental variables (IV) corresponding genes were used to further investigate the potential mechanism of myeloid cells influencing the pathogenesis of PD.

RESULTS

We investigated the impact of four immunophenotypes on the risk of PD, including Im MDSC% CD33dim HLA DR- CD66b- (relative count), CD33dim HLA DR+ CD11b+% CD33dim HLA DR+ (relative count), and CD11b on Mo MDSC (MFI) and CD11b on CD33br HLA DR+ CD14dim (MFI), while an immunophenotype's protective effect on PD was observed CD45 on Im MDSC (MFI). The results of bioinformatics analysis showed that CD33, NTRK2, PLD2, GRIK2 and RELN had protein interactions with the risk genes of PD.

CONCLUSIONS

Our study has demonstrated a close genetic correlation between different subtypes of myeloid cells and PD, providing guidance for early identification and immunotherapeutic development in patients with PD.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Hypoxia inducible factor-1α regulates microglial innate immune memory and the pathology of Parkinson's disease

Neuroinflammation is one of the core pathological features of Parkinson's disease (PD). Innate immune cells play a crucial role in the progression of PD. Microglia, the major innate immune cells in the brain, exhibit innate immune memory effects and are recognized as key regulators of neuroinflammatory responses. Persistent modifications of microglia provoked by the first stimuli are pivotal for innate immune memory, resulting in an enhanced or suppressed immune response to second stimuli, which is known as innate immune training and innate immune tolerance, respectively. In this study, LPS was used to establish in vitro and in vivo models of innate immune memory. Microglia-specific Hif-1α knockout mice were further employed to elucidate the regulatory role of HIF-1α in innate immune memory and MPTP-induced PD pathology. Our results showed that different paradigms of LPS could induce innate immune training or tolerance in the nigrostriatal pathway of mice. We found that innate immune tolerance lasting for one month protected the dopaminergic system in PD mice, whereas the effect of innate immune training was limited. Deficiency of HIF-1α in microglia impeded the formation of innate immune memory and exerted protective effects in MPTP-intoxicated mice by suppressing neuroinflammation. Therefore, HIF-1α is essential for microglial innate immune memory and can promote neuroinflammation associated with PD.

Ferroptosis: Iron-mediated cell death linked to disease pathogenesis

Ferroptosis is an iron-mediated regulatory cell death pattern characterized by oxidative damage. The molecular regulating mechanisms are related to iron metabolism, lipid peroxidation, and glutathione metabolism. Additionally, some immunological signaling pathways, such as the cyclic GMP-AMP synthase-stimulator ofinterferon genes axis, Janus kinase-signal transducer and activator of transcription 1 axis, and transforming growth factor beta 1-Smad3 axis may also participate in the regulation of ferroptosis. Studies have shown that ferroptosis is closely related to many diseases such as cancer, neurodegenerative diseases, inflammatory diseases, and autoimmune diseases. Considering the pivotal role of ferroptosis-regulating signaling in the pathogenesis of diverse diseases, the development of ferroptosis inducers or inhibitors may have significant clinical potential for the treatment of the aforementioned conditions.

Gasdermin and MLKL necrotic cell death effectors: Signaling and diseases

Diverse inflammatory conditions, from infections to autoimmune disease, are often associated with cellular damage and death. Apoptotic cell death has evolved to minimize its inflammatory potential. By contrast, necrotic cell death via necroptosis and pyroptosis-driven by membrane-damaging MLKL and gasdermins, respectively-can both initiate and propagate inflammatory responses. In this review, we provide insights into the function and regulation of MLKL and gasdermin necrotic effector proteins and drivers of plasma membrane rupture. We evaluate genetic evidence that MLKL- and gasdermin-driven necrosis may either provide protection against, or contribute to, disease states in a context-dependent manner. These cumulative insights using gene-targeted mice underscore the necessity for future research examining pyroptotic and necroptotic cell death in human tissue, as a basis for developing specific necrotic inhibitors with the potential to benefit a spectrum of pathological conditions.

The pyroptosis mediated biomarker pattern: an emerging diagnostic approach for Parkinson's disease

BACKGROUND

Parkinson's disease (PD) affects 1% of people over 60, and long-term levodopa treatment can cause side effects. Early diagnosis is of great significance in slowing down the pathological process of PD. Multiple pieces of evidence showed that non-coding RNAs (ncRNAs) could participate in the progression of PD pathology. Pyroptosis is known to be regulated by ncRNAs as a key pathological feature of PD. Therefore, evaluating ncRNAs and pyroptosis-related proteins in serum could be worthy biomarkers for early diagnosis of PD.

METHODS

NcRNAs and pyroptosis/inflammation mRNA levels were measured with reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Luciferase assays were performed to confirm GSDME as a target of miR-675-5p and HMGB1 as a target of miR-1247-5p. In the serum of healthy controls (n = 106) and PD patients (n = 104), RT-qPCR was utilized to assess miR-675-5p, miR-1247-5p, and two related ncRNAs (circSLC8A1and lncH19) levels. The enzyme-linked immunosorbent assay measured serum levels of pyroptosis-related proteins in controls (n = 54) and PD patients (n = 70).

RESULTS

Our data demonstrated that miR-675-5p and miR-1247-5p significantly changed in PD neuron and animal models. Overexpressed miR-675-5p or downregulated miR-1247-5p could regulate pyroptosis and inflammation in PD neuron models. Using the random forest algorithm, we constructed a classifier based on PD neuron-pyroptosis pathology (four ncRNAs and six proteins) having better predictive power than single biomarkers (AUC = 92%). Additionally, we verified the performance of the classifier in early-stage PD patients (AUC ≥ 88%).

CONCLUSION

Serum pyroptosis-related ncRNAs and proteins could serve as reliable, inexpensive, and non-invasive diagnostic biomarkers for PD.

LIMITATIONS

All participants were from the same region. Additionally, longitudinal studies in the aged population are required to explore the practical application value of the classifier.