Activation of the executioner caspases-3 and -7 promotes microglial pyroptosis in models of multiple sclerosis

Luteolin alleviates cadmium-induced metabolism disorder through antioxidant and anti-inflammatory mechanisms in chicken kidney

Cadmium (Cd) is a common environmental pollutant associated with an increased incidence of renal metabolic diseases. Luteolin (Lut), a natural flavonoid, is widely used for its multifaceted therapeutic properties in inflammatory diseases. However, whether Lut protects against Cd-induced nephrotoxicity is still equivocal. The present study investigated the effects of Lut supplementation on renal oxidative stress, inflammation and metabolism and their related mechanisms. Therefore, 40 chickens were treated with Cd and/or Lut with automatic water and free food intake for 1 mo and then the kidney tissues were collected to explore this issue. In this study, Cd exposure induced renal glycolipid metabolism disorders and resultant kidney damage by periodic acid Schiff (PAS) staining, Oil Red O staining, total cholesterol (TC), triglyceride (TG), and glucose (Glu) levels in kidney, which were significantly ameliorated by Lut. Moreover, Lut also normalized the expression levels of factors related to Cd-disturbed glycolipid metabolism, improving metabolic homeostasis, and contributing to alleviating kidney damage. Furthermore, Lut demonstrated therapeutic potential against Cd-induced renal oxidative stress and inflammation by enhancing antioxidant capacity and inhibiting cytokine production in the kidney tissues. Mechanistically, Lut activated the AMPK/SIRT1/FOXO1 signaling pathway, attenuating oxidative stress and inflammatory responses, ameliorating the metabolic disturbance. In conclusion, these observations demonstrate that Lut treatment activates AMPK/SIRT1/FOXO1 signaling pathway, decreases oxidative stress and inflammation response, which may contribute to prevent Cd-induced metabolism disorder and consequent kidney damage.

Complicated Role of Post-translational Modification and Protease-Cleaved Fragments of Tau in Alzheimer's Disease and Other Tauopathies

Tau, a microtubule-associated protein predominantly localized in neuronal axons, plays a crucial role in promoting microtubule assembly, stabilizing their structure, and participating in axonal transport. Perturbations in tau's structure and function are implicated in the pathogenesis of neurodegenerative diseases collectively known as tauopathies, the most common disorder of which is Alzheimer's disease (AD). In tauopathies, it has been found that tau has a variety of post-translational modification (PTM) abnormalities and/or tau is cleaved into a variety of fragments by some specific proteolytic enzymes; however, the precise contributions of these abnormal modifications and fragments to disease onset and progression remain incompletely understood. Herein, we provide an overview about the involvement of distinctive abnormal tau PTMs and different tau fragments in the pathogenesis of AD and other tauopathies and discuss the involvement of proteolytic enzymes such as caspases, calpains, and asparagine endopeptidase in mediating tau cleavage while also addressing the intercellular transmission role played by tau. We anticipate that further exploration into PTMs and fragmented forms of tau will yield valuable insights for diagnostic approaches and therapeutic interventions targeting AD and other related disorders.

Upregulation of circ0000381 attenuates microglial/macrophage pyroptosis after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202406000-00041/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

Neuroinflammation exacerbates secondary damage after spinal cord injury, while microglia/macrophage pyroptosis is important to neuroinflammation. Circular RNAs (circRNAs) play a role in the central nervous system. However, the functional role and mechanism of circRNAs in regulating microglia/macrophage pyroptosis after spinal cord injury are still poorly studied. In the present study, we detected microglia/macrophage pyroptosis in a female rat model of spinal cord injury, along with upregulated levels of circ0000381 in the spinal cord. Our further experimental results suggest that circ0000381 may function as a sponge to sequester endogenous microRNA423-3p (miR-423-3p), which can increase the expression of NOD-like receptor 3 (NLRP3), a pyroptosis marker. Therefore, upregulation of circ0000381 may be a compensatory change after spinal cord injury to attenuate microglia/macrophage pyroptosis. Indeed, knockdown of circ0000381 expression exacerbated microglia/macrophage pyroptosis. Collectively, our findings provide novel evidence for the upregulation of circ0000381, which may serve as a neuroprotective mechanism to attenuate microglia/macrophage pyroptosis after spinal cord injury. Accordingly, circ0000381 may be a novel therapeutic target for the treatment of spinal cord injury.

Sigma-1 Receptor Inhibition Reduces Mechanical Allodynia and Modulate Neuroinflammation in Chronic Neuropathic Pain

Neuropathic pain is one of the most debilitating forms of chronic pain, resulting from an injury or disease of the somatosensory nervous system, which induces abnormal painful sensations including allodynia and hyperalgesia. Available treatments are limited by severe side-effects and reduced efficacy in the chronic phase of the disease. Sigma-1 receptor (σ1R) has been identified as a chaperone protein, which modulate opioid receptors activities and the functioning of several ion channels, exerting a role in pain transmission. As such, it represents a druggable target to treat neuropathic pain. This study aims at investigating the therapeutic potential of the novel compound (+)-2R/S-LP2, a σ1R antagonist, in reducing painful behaviour and modulating the neuroinflammatory environment. We showed that repeated administration of the compound significantly inhibited mechanical allodynia in neuropathic rats, increasing the withdrawal threshold as compared to CCI-vehicle rats. Moreover, we found that (+)-2R/S-LP2-mediated effects resolve the neuroinflammatory microenvironment by reducing central gliosis and pro-inflammatory cytokines expression levels. This effect was coupled with a significant reduction of connexin 43 (Cx43) expression levels and gap junctions/hemichannels mediated microglia-to-astrocyte communication. These results suggest that inhibition of σ1R significantly attenuates neuropathic pain chronicization, thus representing a viable effective strategy.

Role of pyroptosis in the pathogenesis of various neurological diseases

Pyroptosis, an inflammatory programmed cell death process, has recently garnered significant attention due to its pivotal role in various neurological diseases. This review delves into the intricate molecular signaling pathways governing pyroptosis, encompassing both caspase-1 dependent and caspase-1 independent routes, while emphasizing the critical role played by the inflammasome machinery in initiating cell death. Notably, we explore the Nucleotide-binding domain leucine-rich repeat (NLR) containing protein family, the Absent in melanoma 2-like receptor family, and the Pyrin receptor family as essential activators of pyroptosis. Additionally, we comprehensively examine the Gasdermin family, renowned for their role as executioner proteins in pyroptosis. Central to our review is the interplay between pyroptosis and various central nervous system (CNS) cell types, including astrocytes, microglia, neurons, and the blood-brain barrier (BBB). Pyroptosis emerges as a significant factor in the pathophysiology of each cell type, highlighting its far-reaching impact on neurological diseases. This review also thoroughly addresses the involvement of pyroptosis in specific neurological conditions, such as HIV infection, drug abuse-mediated pathologies, Alzheimer's disease, and Parkinson's disease. These discussions illuminate the intricate connections between pyroptosis, chronic inflammation, and cell death in the development of these disorders. We also conducted a comparative analysis, contrasting pyroptosis with other cell death mechanisms, thereby shedding light on their unique aspects. This approach helps clarify the distinct contributions of pyroptosis to neuroinflammatory processes. In conclusion, this review offers a comprehensive exploration of the role of pyroptosis in various neurological diseases, emphasizing its multifaceted molecular mechanisms within various CNS cell types. By elucidating the link between pyroptosis and chronic inflammation in the context of neurodegenerative disorders and infections, it provides valuable insights into potential therapeutic targets for mitigating these conditions.

Caspase cleavage of gasdermin E causes neuronal pyroptosis in HIV-associated neurocognitive disorder

Despite effective antiretroviral therapies, 20-30% of persons with treated HIV infection develop a neurodegenerative syndrome termed HIV-associated neurocognitive disorder (HAND). HAND is driven by HIV expression coupled with inflammation in the brain but the mechanisms underlying neuronal damage and death are uncertain. The inflammasome-pyroptosis axis coordinates an inflammatory type of regulated lytic cell death that is underpinned by the caspase-activated pore-forming gasdermin proteins. The mechanisms driving neuronal pyroptosis were investigated herein in models of HAND, using multi-platform molecular and morphological approaches that included brain tissues from persons with HAND and simian immunodeficiency virus (SIV)-infected non-human primates as well as cultured human neurons. Neurons in the frontal cortices from persons with HAND showed increased cleaved gasdermin E (GSDME), which was associated with β-III tubulin degradation and increased HIV levels. Exposure of cultured human neurons to the HIV-encoded viral protein R (Vpr) elicited time-dependent cleavage of GSDME and Ninjurin-1 (NINJ1) induction with associated cell lysis that was inhibited by siRNA suppression of both proteins. Upstream of GSDME cleavage, Vpr exposure resulted in activation of caspases-1 and 3. Pretreatment of Vpr-exposed neurons with the caspase-1 inhibitor, VX-765, reduced cleavage of both caspase-3 and GSDME, resulting in diminished cell death. To validate these findings, we examined frontal cortical tissues from SIV-infected macaques, disclosing increased expression of GSDME and NINJ1 in cortical neurons, which was co-localized with caspase-3 detection in animals with neurological disease. Thus, HIV infection of the brain triggers the convergent activation of caspases-1 and -3, which results in GSDME-mediated neuronal pyroptosis in persons with HAND. These findings demonstrate a novel mechanism by which a viral infection causes pyroptotic death in neurons while also offering new diagnostic and therapeutic strategies for HAND and other neurodegenerative disorders.

Gasdermin D activation in oligodendrocytes and microglia drives inflammatory demyelination in progressive multiple sclerosis

Neuroinflammation coupled with demyelination and neuro-axonal damage in the central nervous system (CNS) contribute to disease advancement in progressive multiple sclerosis (P-MS). Inflammasome activation accompanied by proteolytic cleavage of gasdermin D (GSDMD) results in cellular hyperactivation and lytic death. Using multiple experimental platforms, we investigated the actions of GSDMD within the CNS and its contributions to P-MS. Brain tissues from persons with P-MS showed significantly increased expression of GSDMD, NINJ1, IL-1β, and -18 within chronic active demyelinating lesions compared to MS normal appearing white matter and nonMS (control) white matter. Conditioned media (CM) from stimulated GSDMD+/+ human macrophages caused significantly greater cytotoxicity of oligodendroglial and neuronal cells, compared to CM from GSDMD-/- macrophages. Oligodendrocytes and CNS macrophages displayed increased Gsdmd immunoreactivity in the central corpus callosum (CCC) of cuprizone (CPZ)-exposed Gsdmd+/+ mice, associated with greater demyelination and reduced oligodendrocyte precursor cell proliferation, compared to CPZ-exposed Gsdmd-/- animals. CPZ-exposed Gsdmd+/+ mice exhibited significantly increased G-ratios and reduced axonal densities in the CCC compared to CPZ-exposed Gsdmd-/- mice. Proteomic analyses revealed increased brain complement C1q proteins and hexokinases in CPZ-exposed Gsdmd-/- animals. [18F]FDG PET imaging showed increased glucose metabolism in the hippocampus and whole brain with intact neurobehavioral performance in Gsdmd-/- animals after CPZ exposure. GSDMD activation in CNS macrophages and oligodendrocytes contributes to inflammatory demyelination and neuroaxonal injury, offering mechanistic and potential therapeutic insights into P-MS pathogenesis.

Remote limb ischemic postconditioning inhibits microglia pyroptosis by modulating HGF after acute ischemia stroke

The repetitive inflation-deflation of a blood pressure cuff on a limb is known as remote limb ischemic postconditioning (RIPostC). It prevents brain damage induced by acute ischemia stroke (AIS). Pyroptosis, executed by the pore-forming protein gasdermin D (GSDMD), is a type of regulated cell death triggered by proinflammatory signals. It contributes to the pathogenesis of ischemic brain injury. However, the effects of RIPostC on pyroptosis following AIS remain largely unknown. In our study, linear correlation analysis confirmed that serum GSDMD levels in AIS patients upon admission were positively correlated with NIHSS scores. RIPostC treatment significantly reduced GSDMD level compared with patients without RIPostC at 3 days post-treatment. Besides, middle cerebral artery occlusion (MCAO) surgery was performed on C57BL/6 male mice and RIPostC was induced immediately after MCAO. We found that RIPostC suppressed the activation of NLRP3 inflammasome to reduce the maturation of GSDMD, leading to decreased pyroptosis in microglia after AIS. Hepatocyte growth factor (HGF) was identified using the high throughput screening. Importantly, HGF siRNA, exogenous HGF, and ISG15 siRNA were used to reveal that HGF/ISG15 is a possible mechanism of RIPostC regulation in vivo and in vitro.

Modulation of mitochondrial permeability transition pore opening by Myricetin and prediction of its-drug-like potential using in silico approach

Myricetin has been demonstrated to have multiple biological functions with promising research and development prospects. This study investigated the effect of myricetin on liver mitochondrial membrane permeability transition pores and its inhibitory potential on proteins that are important in the apoptotic process in silico. Mitochondrial swelling was assessed as changes in absorbance under succinate-energized conditions. Cytochrome c release, mitochondrial-lipid peroxidation, caspase 3 and 9 expressions, as well as calcium ATPase, were assessed. Pharmacokinetic properties of myricetin were predicted through the SwissADME server while the binding affinity of myricetin toward the proteins was computed using the AutodockVina Screening tool. The conformational stability of protein-ligand interactions was evaluated using molecular dynamics simulations analysis through the iMODS server. Myricetin inhibited the opening of the mitochondrial permeability transition pore and also reversed the increase in mitochondrial lipid peroxidation caused by calcium and other toxicants. Myricetin also caused a reduction in the expression of caspase 3 and 9 as well as calcium ATPase activity. The molecular docking results revealed that myricetin had a considerable binding affinity to the pocket site of caspase 3 and 9 as well as calcium ATPase. Myricetin showed a good drug-likeness based on the predicted pharmacokinetic properties as revealed by low CYP 450 inhibitory promiscuity and relatively low toxicity. It could therefore be suggested that myricetin could be useful in the management of diseases where too many apoptosis occur characterized by excessive tissue wastage such as neurodegenerative conditions and could as well play a role in protecting the physicochemical properties of membrane bilayers from free radical-induced severe cellular damage.

COVID-19 Induces Neuroinflammation and Suppresses Peroxisomes in the Brain

OBJECTIVE

Peroxisome injury occurs in the central nervous system (CNS) during multiple virus infections that result in neurological disabilities. We investigated host neuroimmune responses and peroxisome biogenesis factors during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using a multiplatform strategy.

METHODS

Brain tissues from coronavirus disease 2019 (COVID-19) (n = 12) and other disease control (ODC) (n = 12) patients, as well as primary human neural cells and Syrian hamsters, infected with a clinical variant of SARS-CoV-2, were investigated by droplet digital polymerase chain reaction (ddPCR), quantitative reverse transcriptase PCR (RT-qPCR), and immunodetection methods.

RESULTS

SARS-CoV-2 RNA was detected in the CNS of 4 patients with COVID-19 with viral protein (NSP3 and spike) immunodetection in the brainstem. Olfactory bulb, brainstem, and cerebrum from patients with COVID-19 showed induction of pro-inflammatory transcripts (IL8, IL18, CXCL10, NOD2) and cytokines (GM-CSF and IL-18) compared to CNS tissues from ODC patients (p < 0.05). Peroxisome biogenesis factor transcripts (PEX3, PEX5L, PEX11β, and PEX14) and proteins (PEX3, PEX14, PMP70) were suppressed in the CNS of COVID-19 compared to ODC patients (p < 0.05). SARS-CoV-2 infection of hamsters revealed viral RNA detection in the olfactory bulb at days 4 and 7 post-infection while inflammatory gene expression was upregulated in the cerebrum of infected animals by day 14 post-infection (p < 0.05). Pex3 transcript levels together with catalase and PMP70 immunoreactivity were suppressed in the cerebrum of SARS-CoV-2 infected animals (p < 0.05).

INTERPRETATION

COVID-19 induced sustained neuroinflammatory responses with peroxisome biogenesis factor suppression despite limited brainstem SARS-CoV-2 neurotropism in humans. These observations offer insights into developing biomarkers and therapies, while also implicating persistent peroxisome dysfunction as a contributor to the neurological post-acute sequelae of COVID-19. ANN NEUROL 2023;94:531-546.

GSDMD knockdown attenuates phagocytic activity of microglia and exacerbates seizure susceptibility in TLE mice

BACKGROUND

Temporal lobe epilepsy (TLE) is often characterized pathologically by severe neuronal loss in the hippocampus. Phagocytic activity of microglia is essential for clearing apoptotic neuronal debris, allowing for repair and regeneration. Our previous research has shown that gasdermin D (GSDMD)-mediated pyroptosis is involved in the pathogenesis of TLE. However, whether GSDMD-mediated pyroptosis influences the accumulation of apoptotic neurons remains unclear. Therefore, the present study was designed to investigate whether phagocytic activity of microglia is involved in GSDMD-mediated pyroptosis and the pathogenesis of TLE.

METHODS

To establish a TLE model, an intra-amygdala injection of kainic acid (KA) was performed. The Racine score and local field potential (LFP) recordings were used to assess seizure severity. Neuronal death in the bilateral hippocampus was assessed by Nissl staining and TUNEL staining. Microglial morphology and phagocytic activity were detected by immunofluorescence and verified by lipopolysaccharide (LPS) and the P2Y12R agonist 2MeSADP.

RESULTS

GSDMD knockdown augmented the accumulation of apoptotic neurons and seizure susceptibility in TLE mice. Microglia activated and transition to the M1 type with increased pro-inflammatory cytokines. Furthermore, GSDMD knockdown attenuated the migration and phagocytic activity of microglia. Of note, LPS-activated microglia attenuated seizure susceptibility and the accumulation of apoptotic neurons in TLE after GSDMD knockdown. A P2Y12R selective agonist, 2MeSADP, enhanced the migration and phagocytic activity of microglia.

CONCLUSIONS

Our results demonstrate that GSDMD knockdown exacerbates seizure susceptibility and the accumulation of apoptotic neurons by attenuating phagocytic activity of microglia. These findings suggest that GSDMD plays a protective role against KA-induced seizure susceptibility.

Ursolic acid ameliorates traumatic brain injury in mice by regulating microRNA-141-mediated PDCD4/PI3K/AKT signaling pathway

BACKGROUND

Neuronal apoptosis and inflammation are the key pathogenic features of secondary brain injury, which results in the neurological impairment that traumatic brain injury (TBI) patients experience. Ursolic Acid (UA) has been shown to have neuroprotective properties against brain damage, however, detailed mechanisms have not been fully disclosed. Research on brain-related microRNAs (miRNAs) has opened up new possibilities for the neuroprotective treatment of UA by manipulating miRNAs. The present study was designed to investigate the impact of UA on neuronal apoptosis and the inflammatory response in TBI mice.

METHODS

The mice's neurologic condition was assessed using the modified neurological severity score (mNSS) and the learning and memory abilities were assessed using the Morris water maze (MWM). Cell apoptosis, oxidative stress, and inflammation were utilized to examine the impact of UA on neuronal pathological damage. miR-141-3p was selected to evaluate whether UA influences miRNAs in a way that has neuroprotective benefits.

RESULTS

The results showed that UA markedly decreased brain edema and neuronal mortality through oxidative stress and neuroinflammation in TBI mice. Using data from the GEO database, we found that miR-141-3p was considerably downregulated in TBI mice and that this downregulation was reversed by UA treatment. Further studies have shown that UA regulates miR-141-3p expression to exhibit its neuroprotective effect in mouse models and cell injury models. Then, miR-141-3p was discovered to directly target PDCD4 in TBI mice and neurons, a well-known PI3K/AKT pathway regulator in the neurons. Most importantly, the upregulation of phosphorylated (p)-AKT and p-PI3K provided the most compelling evidence that UA reactivated the PI3K/AKT pathway in the TBI mouse model, which was through regulating miR-141-3p.

CONCLUSION

Our findings support the notion that UA can improve TBI by modulating miR-141 mediated PDCD4/PI3K/AKT signaling pathway.

Elsholtzia bodinieri Vaniot ameliorated acute lung injury in mice by regulating pyroptosis, inflammation, oxidative stress and macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

Elsholtzia bodinieri Vaniot, perennial herbs, a traditional Yunnan Chinese herbal medicine. Its whole herb can be used as commonly used herbs to cure fever, headache, inflammation, indigestion etc., and its tender tip can also be used as tea in Yunnan of China. However, the protective mechanism of Elsholtzia bodinieri Vaniot on acute lung injury (ALI) still needs to be explored.

AIM OF STUDY

ALI is characterized by acute respiratory inflammation, which remains a significant source of morbidity and mortality. The current study with the aim of determining the therapeutic the efficacy of E. bodinieri Vaniot on lipopolysaccharide-induced ALI, moreover uncovered the underlying gene-regulated framework, so E. bodinieri Vaniot might serve as functional food for adjuvant therapy or therapeutic agent.

MATERIALS AND METHODS

These potential pharmacological targets of E. bodinieri Vaniot against ALI were analyzed by multiple bioinformatics databases. E. bodinieri Vaniot methanol extract (EBE) was obtained by ultrasonic-assisted extraction method, and detected by UHPLC-ESI-HRMS/MS. These pyroptosis, inflammation and oxidative stress associated factors were measured using ELISA assay, western blotting, and histopathological examination to assess the effects of EBE. EcoTyper and immunofluorescence staining were employed to estimate macrophage polarization states in ALI lungs tissue.

RESULTS

In ALI lung tissues, EBE treatment could increase B cell leukemia/lymphoma 2 (BCL2) to inhibit pyroptosis, downregulate prostaglandin-endoperoxide synthase 2 (PTGS2) to attenuate inflammation, upregulating NAD(P)H dehydrogenase, quinone 1 (NQO1) to alleviate oxidative stress and induce macrophage polarization toward the M2 phenotype.

CONCLUSION

E. bodinieri Vaniot ameliorated ALI thought regulating pyroptosis, inflammation, oxidative stress and macrophage polarization, as well as could be a promising source for therapeutic agent.

GSDMD knockdown exacerbates hippocampal damage and seizure susceptibility by crosstalk between pyroptosis and apoptosis in kainic acid-induced temporal lobe epilepsy

BACKGROUND

Neuronal loss is a vital pathological feature of temporal lobe epilepsy (TLE). However, the exact mechanism of neuronal loss in TLE is not fully understood. Pyroptosis, a novel form of programmed cell death (PCD), has been considered a contributor to the pathogenesis of TLE. However, recent studies have implicated extensive molecular crosstalk among pyroptosis, apoptosis, and necroptosis in various diseases, and they can be transformed to each other according to different contexts. This study aimed to investigate whether gasdermin D (GSDMD)-mediated pyroptosis is involved in the pathogenesis of TLE and whether crosstalk exists in the process of the modulation of pyroptosis.

METHODS

The TLE model was established by intra-amygdala injection of kainic acid. The Racine score and local field potential (LFP) recordings were used to assess seizure severity. Western blotting and immunofluorescence were applied to detect the levels and cellular localization of GSDMD. The neuronal loss and type of neuronal death in the bilateral hippocampus were assessed by Nissl staining and flow cytometry analysis. The underlying crosstalk among pyroptosis, apoptosis, and necroptosis was explored by western blot and verified by VX765.

RESULTS

GSDMD was significantly upregulated and mainly expressed within the neurons of the hippocampus in the TLE model. Inhibition of pyroptosis by GSDMD knockdown triggered caspase-3-mediated apoptosis, leading to excess neuronal loss and deterioration of epileptic behaviors. Blocking caspase-1 markedly inhibited caspase-3-mediated apoptosis and improved epileptic behaviors under GSDMD knockdown.

CONCLUSIONS

Our results demonstrate that GSDMD-mediated pyroptosis is involved in the pathogenesis of TLE. However, inhibition of GSDMD triggers caspase-1-mediated crosstalk between pyroptosis and apoptosis, which exacerbates neuronal loss and seizure susceptibility. Therefore, the complex crosstalk among different forms of PCD should be considered when a potential molecular target in the single PCD pathway is modulated. On the other hand, along with further studies of molecular crosstalk among the PCD pathways, taking advantage of crosstalk to attenuate neuronal loss may provide new insight for the clinical therapy of TLE.

Exosomal miR-23b-3p from bone mesenchymal stem cells alleviates experimental autoimmune encephalomyelitis by inhibiting microglial pyroptosis

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system and is marked by inflammation and damage to the myelin sheath surrounding nerve fibers. Recent studies have highlighted the therapeutic value of exosomes (Exos) obtained from bone marrow mesenchymal stem cells (BMSCs) in MS treatment. These BMSC-Exos contain biologically active molecules that show promising results in preclinical evaluations. The aim of this study was to investigate the mechanism of BMSC-Exos containing miR-23b-3p in both LPS-stimulated BV2 microglia and in experimental autoimmune encephalomyelitis (EAE), an animal model for MS. Exos were isolated from BMSCs, and their effects were evaluated in vitro by co-culturing with BV2 microglia. The interaction between miR-23b-3p and its downstream targets was also explored. The efficacy of BMSC-Exos was further verified in vivo by injecting the Exos into EAE mice. The results showed that BMSC-Exos containing miR-23b-3p reduced microglial pyroptosis in vivo by specifically binding to and suppressing the expression of NEK7. In vivo, BMSC-Exos containing miR-23b-3p alleviated the severity of EAE by decreasing microglial inflammation and pyroptosis via the repression of NEK7. These findings provide new insights into the therapeutic potential of BMSC-Exos containing miR-23b-3p for MS.

Role of DAMPs and cell death in autoimmune diseases: the example of multiple sclerosis

Multiple sclerosis is a chronic neuroinflammatory demyelinating disease of the central nervous system (CNS) of unknown etiology and still incompletely clarified pathogenesis. The disease is generally considered a disorder resulting from a complex interplay between environmental risk factors and predisposing causal genetic variants. To examine the etiopathogenesis of the disease, two complementary pre-clinical models are currently discussed: the "outside-in" model proposing a peripherally elicited inflammatory/autoimmune attack against degraded myelin as the cause of the disease, and the "inside-out" paradigm implying a primary cytodegenerative process of cells in the CNS that triggers secondary reactive inflammatory/autoimmune responses against myelin debris. In this review, the integrating pathogenetic role of damage-associated molecular patterns (DAMPs) in these two scenario models is examined by focusing on the origin and sources of these molecules, which are known to promote neuroinflammation and, via activation of pattern recognition receptor-bearing antigen-presenting cells, drive and shape autoimmune responses. In particular, environmental factors are discussed that are conceptually defined as agents which produce endogenous DAMPs via induction of regulated cell death (RCD) or act themselves as exogenous DAMPs. Indeed, in the field of autoimmune diseases, including multiple sclerosis, recent research has focused on environmental triggers that cause secondary events in terms of subroutines of RCD, which have been identified as prolific sources of DAMPs. Finally, a model of a DAMP-driven positive feed-forward loop of chronic inflammatory demyelinating processes is proposed, aimed at reconciling the competing "inside-out" and "outside-in" paradigms.

Taxifolin attenuates neuroinflammation and microglial pyroptosis via the PI3K/Akt signaling pathway after spinal cord injury

Spinal cord injury (SCI) is a severe injury characterized by neuroinflammation and oxidative stress. Taxifolin is exhibits anti-inflammatory and antioxidative activities in neurologic diseases. However, the roles and mechanisms of taxifolin in neuroinflammation and microglial pyroptosis after SCI remain unclear. The present study aims to investigate the effect of taxifolin on SCI and its potential underlying mechanisms in in vivo and in vitro models. In this study, taxifolin markedly reduced microglial activation mediated oxidative stress, and inhibited the expression of pyroptosis-related proteins (NLRP3, GSDMD, ASC, and Caspase-1) and inflammatory cytokines (IL-1β and IL-18) after SCI, as shown by immunofluorescence staining and western blot assays. In addition, taxifolin promoted axonal regeneration and improved functional recovery after SCI. In vitro studies showed that taxifolin attenuated the activation of microglia and oxidative stress after lipopolysaccharide (LPS) + adenosine-triphosphate (ATP) stimulation in BV2 cells. We also observed that taxifolin inhibited the pyroptosis-related proteins and reduced the release of inflammatory cytokines. Moreover, to explore how taxifolin exerts its effects on microglial pyroptosis and axonal regeneration of neurons, we performed an in vitro study in BV-2 cells and PC12 cells co-culture. The results revealed that taxifolin facilitated axonal regeneration of PC12 cells in co-culture with LPS + ATP-induced BV-2 cells. Mechanistically, taxifolin regulated microglial pyroptosis via the PI3K/AKT signaling pathway. Taken together, these results suggest that taxifolin alleviates neuroinflammation and microglial pyroptosis through the PI3K/AKT signaling pathway after SCI, and promotes axonal regeneration and improves functional recovery, suggesting that taxifolin may represent a potential therapeutic agent for SCI.

Elsholtzia bodinieri Vaniot Ameliorated Acute Lung Injury by NQO1, BCL2 and PTGS2 In Silico and In Vitro Analyses

Acute lung injury (ALI) is a clinical respiratory disease caused by various factors, which lacks effective pharmacotherapy to reduce the mortality rate. Elsholtzia bodinieri Vaniot is an annual herbaceous plant used as a traditional herbal tea and folk medicine. Here we used bioinformatic databases and software to explore and analyze the potential key genes in ALI regulated by E. bodinieri Vaniot, including B cell leukemia/lymphoma 2 (Bcl2), prostaglandin-endoperoxide synthase 2 (Ptgs2) and NAD(P)H dehydrogenase, quinone 1 (Nqo1). In an inflammatory cells model, we verified bioinformatics results, and further mechanistic analysis showed that methanol extract of E. bodinieri Vaniot (EBE) could alleviate oxidative stress by upregulating the expression of NQO1, suppress pyroptosis by upregulating the expression of BCL2, and attenuate inflammation by downregulating the expression of PTGS2. In sum, our results demonstrated that EBE treatment could alleviate oxidative stress, suppress pyroptosis and attenuate inflammation by regulating NQO1, BCL2 and PTGS2 in a cells model, and E. bodinieri Vaniot might be a promising source for functional food or as a therapeutic agent.

Nuclear translocation of Gasdermin D sensitizes colorectal cancer to chemotherapy in a pyroptosis-independent manner

Gasdermin D (GSDMD) has recently been identified as a cytoplasmic effector protein that plays a central role in pyroptosis of immune cells. However, GSDMD is a universally expressed protein, and its function beyond pyroptosis, especially in cancer cells, has not been well characterized. Here, we report that predominant localization of GSDMD in the nucleoplasm in vivo indicates favorable clinical outcomes in colorectal cancer, while a lack of nuclear localization of GSDMD is associated with poor outcomes. Nuclear GSDMD, rather than cytoplasmic GSDMD, inhibits cell growth and promotes apoptosis in colorectal cancer. Hypoxia in the tumor microenvironment accounts for mild or moderate nuclear translocation of GSDMD in vivo. Under the stimulation of chemotherapy drugs, nuclear GSDMD promotes apoptosis via regulation of its subcellular distribution rather than pyroptosis-related cleavage. After nuclear translocation, GSDMD interacts with PARP-1 to dramatically inhibit its DNA damage repair-related function by functioning like the PARP inhibitor olaparib, thus forming a "hypoxia/chemotherapy-GSDMD nuclear translocation-PARP-1 blockade-DNA damage and apoptosis" axis. This study redefines the pyroptosis-independent function of GSDMD and suggests that the subcellular localization of GSDMD may serve as a molecular indicator of clinical outcomes and a promising therapeutic target in colorectal cancer.

Glyphosate, AMPA and glyphosate-based herbicide exposure leads to GFAP, PCNA and caspase-3 increased immunoreactive area on male offspring rat hypothalamus

Glyphosate, aminomethylphosphonic acid (AMPA), and glyphosate-based herbicides altered the neuroendocrine axis, the content of brain neurotransmitters, and behavior in experimental animal models. Glyphosate alone, AMPA or Roundup® Active were administered to postpartum female rats, from P0 to P10, and their water consumption was measured daily. The immunoreactivity for glial fibrillary acidic protein (GFAP), proliferating cell nuclear antigen (PCNA) and caspase-3 was measured in the anterior, medial preoptic, periventricular, supraoptic and lateroanterior hypothalamic nuclei of P0-P10 male pups after exposure, via lactation, to these xenobiotics. Puppies exposed to glyphosate had a moderate level of GFAP with no overlapping astrocyte processes, but this overlapping was observed after Roundup® Active or AMPA exposure. After being exposed to Roundup® Active or AMPA, PCNA-positive cells with strong immunoreactivity were found in some hypothalamic nuclei. Cells containing caspase-3 were found in all hypothalamic nuclei studied, but the labeling was stronger after Roundup® Active or AMPA exposure. Xenobiotics significantly increased the immunoreactivity area for all of the markers studied in the majority of cases (p<0.05). AMPA or Roundup® Active treated animals had a greater area of PCNA immunoreactivity than control or glyphosate alone treated animals (p<0.05). The effects observed after xenobiotic exposure were not due to increased water intake. The increased immunoreactivity areas observed for the markers studied suggest that xenobiotics induced a neuro-inflammatory response, implying increased cell proliferation, glial activation, and induction of apoptotic pathways. The findings also show that glyphosate metabolites/adjuvants and/or surfactants present in glyphosate commercial formulations had a greater effect than glyphosate alone. In summary, glyphosate, AMPA, and glyphosate-based herbicides altered GFAP, caspase-3, and PCNA expression in the rat hypothalamus, altering the neuroendocrine axis.

Microglia Pyroptosis: A Candidate Target for Neurological Diseases Treatment

In addition to its profound implications in the fight against cancer, pyroptosis have important role in the regulation of neuronal injury. Microglia are not only central members of the immune regulation of the central nervous system (CNS), but are also involved in the development and homeostatic maintenance of the nervous system. Under various pathological overstimulation, microglia pyroptosis contributes to the massive release of intracellular inflammatory mediators leading to neuroinflammation and ultimately to neuronal damages. In addition, microglia pyroptosis lead to further neurological damage by decreasing the ability to cleanse harmful substances. The pathogenic roles of microglia in a variety of CNS diseases such as neurodegenerative diseases, stroke, multiple sclerosis and depression, and many other neurological disorders have been gradually unveiled. In the context of different neurological disorders, inhibition of microglia pyroptosis by targeting NOD-like receptor family pyrin domain containing (NLRP) 3, caspase-1 and gasdermins (GSDMs) by various chemical agents as well as natural products significantly improve the symptoms or outcome in animal models. This study will provide new ideas for immunomodulatory treatment of CNS diseases.

PLGA-Quercetin Nano-Formulation Inhibits Cancer Progression via Mitochondrial Dependent Caspase-3,7 and Independent FoxO1 Activation with Concomitant PI3K/AKT Suppression

Quercetin is one of the most important plant flavanols, having several pharmacological and biological uses. Quercetin (Q) is an extremely hydrophobic phytochemical and has poor intracellular absorption, which makes its use limited. Present research demonstrates that quercetin-loaded PLGA nanoparticles (PLGA-QNPs) could overcome its low hydrophilicity and improve its anti-cancer potential. PLGA nanoparticles loaded with Q were prepared by the solvent evaporation technique and its anticancer activity was examined in vitro as well as in vivo. The cell viability was assessed through MTT assay and apoptosis was assayed through Hoechst-PI and EB/AO double staining followed by mitochondrial damage through Mito-tracker RMX-Ros. Gene expression was examined through RT-PCR. Cell cycle arrest in G2/M phase was analyzed through FACS. The results obtained revealed that PLGA-QNPs significantly reduced the viability of human cervical and breast cancer cell lines. PLGA-QNPs induced apoptosis in human cervical cancer cells in a dose dependent manner. The gene expression of PI3K/AKT was down-regulated and FoxO1 was upregulated in PLGA-QNP-treated cells, which showed a high expression level of active Caspase-3 and 7, which are responsible for apoptosis. In addition, PLGA-QNPs reduced the average number of tumors and prolonged the tumor latency period in DMBA-induced mammary adenocarcinoma SD rats. These findings suggest that PLGA-QNPs inhibit cervical and breast cancer progression via mitochondrial dependent Caspase-3 and 7 and mitochondrial independent FoxO1 activation with concomitant suppression of the PI3K/AKT pathway. For future studies, we suggest that potential druggability efficacy and clinical development of anticancer PLGA-QNPs need to be evaluated intensely for successful anticancer drug development.

Greek Fire, Poison Arrows, and Scorpion Bombs: How Tumor Cells Defend Against the Siege Weapons of Cytotoxic T Lymphocytes

CD8⁺ cytotoxic T lymphocytes (CTLs) are the main cellular effectors of the adaptive immune response against cancer cells, which in turn have evolved sophisticated cellular defense mechanisms to withstand CTL attack. Herein we provide a critical review of the pertinent literature on early and late attack/defense events taking place at the CTL/target cell lytic synapse. We examine the earliest steps of CTL-mediated cytotoxicity (“the poison arrows”) elicited within seconds of CTL/target cell encounter, which face commensurately rapid synaptic repair mechanisms on the tumor cell side, providing the first formidable barrier to CTL attack. We examine how breach of this first defensive barrier unleashes the inextinguishable “Greek fire” in the form of granzymes whose broad cytotoxic potential is linked to activation of cell death executioners, injury of vital organelles, and destruction of intracellular homeostasis. Herein tumor cells deploy slower but no less sophisticated defensive mechanisms in the form of enhanced autophagy, increased reparative capacity, and dysregulation of cell death pathways. We discuss how the newly discovered supra-molecular attack particles (SMAPs, the “scorpion bombs”), seek to overcome the robust defensive mechanisms that confer tumor cell resistance. Finally, we discuss the implications of the aforementioned attack/defense mechanisms on the induction of regulated cell death (RCD), and how different contemporary RCD modalities (including apoptosis, pyroptosis, and ferroptosis) may have profound implications for immunotherapy. Thus, we propose that understanding and targeting multiple steps of the attack/defense process will be instrumental to enhance the efficacy of CTL anti-tumor activity and meet the outstanding challenges in clinical immunotherapy.

The AIM2 inflammasome is activated in astrocytes during the late phase of EAE

Inflammasomes are a class of innate immune signaling platforms that activate in response to an array of cellular damage and pathogens. Inflammasomes promote inflammation under many circumstances to enhance immunity against pathogens and inflammatory responses through their effector cytokines, IL-1β and IL-18. Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune conditions influenced by inflammasomes. Despite work investigating inflammasomes during EAE, little remains known concerning the role of inflammasomes in the central nervous system (CNS) during the disease. Here, we used multiple genetically modified mouse models to monitor activated inflammasomes in situ based on oligomerization of apoptosis-associated speck-like protein containing a CARD (ASC) in the spinal cord. Using inflammasome reporter mice, we found heightened inflammasome activation in astrocytes after the disease peak. In contrast, microglia and CNS-infiltrated myeloid cells had few activated inflammasomes in the CNS during EAE. Astrocyte inflammasome activation during EAE was dependent on absent in melanoma 2 (AIM2), but low IL-1β release and no significant signs of cell death were found. Thus, the AIM2 inflammasome activation in astrocytes may have a distinct role from traditional inflammasome-mediated inflammation.

Evolutionary Diversity and Function of Metacaspases in Plants: Similar to but Not Caspases

Caspase is a well-studied metazoan protease involved in programmed cell death and immunity in animals. Obviously, homologues of caspases with evolutionarily similar sequences and functions should exist in plants, and yet, they do not exist in plants. Plants contain structural homologues of caspases called metacaspases, which differ from animal caspases in a rather distinct way. Metacaspases, a family of cysteine proteases, play critical roles in programmed cell death during plant development and defense responses. Plant metacaspases are further subdivided into types I, II, and III. In the type I Arabidopsis MCs, AtMC1 and AtMC2 have similar structures, but antagonistically regulate hypersensitive response cell death upon immune receptor activation. This regulatory action is similar to caspase-1 inhibition by caspase-12 in animals. However, so far very little is known about the biological function of the other plant metacaspases. From the increased availability of genomic data, the number of metacaspases in the genomes of various plant species varies from 1 in green algae to 15 in Glycine max. It is implied that the functions of plant metacaspases will vary due to these diverse evolutions. This review is presented to comparatively analyze the evolution and function of plant metacaspases compared to caspases.

In vivo base editing rescues cone photoreceptors in a mouse model of early-onset inherited retinal degeneration

Leber congenital amaurosis (LCA) is the most common cause of inherited retinal degeneration in children. LCA patients with RPE65 mutations show accelerated cone photoreceptor dysfunction and death, resulting in early visual impairment. It is therefore crucial to develop a robust therapy that not only compensates for lost RPE65 function but also protects photoreceptors from further degeneration. Here, we show that in vivo correction of an Rpe65 mutation by adenine base editor (ABE) prolongs the survival of cones in an LCA mouse model. In vitro screening of ABEs and sgRNAs enables the identification of a variant that enhances in vivo correction efficiency. Subretinal delivery of ABE and sgRNA corrects up to 40% of Rpe65 transcripts, restores cone-mediated visual function, and preserves cones in LCA mice. Single-cell RNA-seq reveals upregulation of genes associated with cone phototransduction and survival. Our findings demonstrate base editing as a potential gene therapy that confers long-lasting retinal protection.

Leber congenital amaurosis is caused by mutations in RPE65 and leads to retinal degeneration in children. Here, the authors show that in vivo base editing can prolong the survival of cone photoreceptors and rescue their function in a mouse model of the disease.

Hydrogen Ion Dynamics as the Fundamental Link between Neurodegenerative Diseases and Cancer: Its Application to the Therapeutics of Neurodegenerative Diseases with Special Emphasis on Multiple Sclerosis

The pH-related metabolic paradigm has rapidly grown in cancer research and treatment. In this contribution, this recent oncological perspective has been laterally assessed for the first time in order to integrate neurodegeneration within the energetics of the cancer acid-base conceptual frame. At all levels of study (molecular, biochemical, metabolic, and clinical), the intimate nature of both processes appears to consist of opposite mechanisms occurring at the far ends of a physiopathological intracellular pH/extracellular pH (pHi/pHe) spectrum. This wide-ranging original approach now permits an increase in our understanding of these opposite processes, cancer and neurodegeneration, and, as a consequence, allows us to propose new avenues of treatment based upon the intracellular and microenvironmental hydrogen ion dynamics regulating and deregulating the biochemistry and metabolism of both cancer and neural cells. Under the same perspective, the etiopathogenesis and special characteristics of multiple sclerosis (MS) is an excellent model for the study of neurodegenerative diseases and, utilizing this pioneering approach, we find that MS appears to be a metabolic disease even before an autoimmune one. Furthermore, within this paradigm, several important aspects of MS, from mitochondrial failure to microbiota functional abnormalities, are analyzed in depth. Finally, and for the first time, a new and integrated model of treatment for MS can now be advanced.

Cell Death Related Proteins Beyond Apoptosis in the CNS

Cell death related (CDR) proteins are a diverse group of proteins whose original function was ascribed to apoptotic cell death signaling. Recently, descriptions of non-apoptotic functions for CDR proteins have increased. In this minireview, we comment on recent studies of CDR proteins outside the field of apoptosis in the CNS, encompassing areas such as the inflammasome and non-apoptotic cell death, cytoskeleton reorganization, synaptic plasticity, mitophagy, neurodegeneration and calcium signaling among others. Furthermore, we discuss the evolution of proteomic techniques used to predict caspase substrates that could potentially explain their non-apoptotic roles. Finally, we address new concepts in the field of non-apoptotic functions of CDR proteins that require further research such the effect of sexual dimorphism on non-apoptotic CDR protein function and the emergence of zymogen-specific caspase functions.

Identification of a pyroptosis-related lncRNA signature in the regulation of prognosis, metabolism signals and immune infiltration in lung adenocarcinoma

Pyroptosis is a cell death pathway that plays a significant role in lung adenocarcinoma (LUAD). Also, studies regarding the correlation between the expression of long non-coding RNAs (lncRNAs) and the mechanism of LUAD has aroused concern around the world. The purpose of this paper is to explore the underlying relationship of differentially expressed lncRNAs and pyroptosis-related genes. The least absolute shrinkage and selection operator (LASSO) algorithm and Cox regression were applied to construct a prognostic risk score model from the TCGA database. A pyroptosis-related five-lncRNA signature (CRNDE, HHLA3, MIR193BHG, LINC00941, LINC01843) was considered to be correlated to the prognosis and immune response of LUAD patients. In addition, the cytological experiments revealed that aberrantly expressed HHLA3 displayed a proliferation promotion role in LUAD cells A549 and H460. Next, the forest and nomogram plots have shown this lncRNA signature could be served as an independent prognostic factor for LUAD. The ROC curves further identified the prognostic value of the five-lncRNA signature. The infiltration of immune cells, such as T cells CD8, T cells CD4 memory resting, T cells CD4 memory activated and M0 macrophages were greatly different between the high-risk group and the low-risk group. It implicated that the signature is significantly effective in immunotherapy of LUAD patients. This study has supplied a novel pyroptosis-related lncRNA signature and provided a predictive model for prognosis and immune response of LUAD patients.

Pyroptosis, and its Role in Central Nervous System Disease

Pyroptosis is an inflammatory form of cell death executed by transmembrane pore-forming proteins known as gasdermins and can be activated in an inflammasome-dependent or -independent manner. Inflammasome-dependent pyroptosis is triggered in response to pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) and has emerged as an important player in the pathogenesis of multiple inflammatory diseases, mainly by releasing inflammatory contents. More recently, numerous studies have revealed the intricate mechanisms of pyroptosis and its role in the development of neuroinflammation in central nervous system (CNS) diseases. In this review, we summarize current understandings of the molecular and regulatory mechanisms of pyroptosis. In addition, we discuss how pyroptosis can drive different forms of neurological diseases and new promising therapeutic strategies targeting pyroptosis that can be leveraged to treat neuroinflammation.

PAF Receptor Inhibition Attenuates Neuronal Pyroptosis in Cerebral Ischemia/Reperfusion Injury

Ischemic stroke is an inflammation-related disease, during which process activation of NLRP3 inflammasome and subsequent pyroptosis play crucial roles. Platelet-activating factor (PAF) is a potent phospholipid regulator of inflammation which exerts its effect via binding specific PAF receptor (PAFR). However, whether PAFR contributes to pyroptosis during ischemia/reperfusion (I/R) injury remains to be elucidated. To explore the underlying effect of PAFR on ischemic stroke from the perspective of pyroptosis, mice were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) injury and primary cultures of mice cerebral cortical neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) injury to mimic I/R in vivo and in vitro, after which indexes associated with pyroptosis were analyzed. Intriguingly, our results indicated that inhibition of PAFR with its inhibitor XQ-1H or PAFR siRNA exerted a neuroprotective effect against I/R injury both in vivo and in vitro. Furthermore, inflammasome activation and pyroptosis after ischemic challenge were attenuated by XQ-1H or PAFR siRNA. Besides, the protection of XQ-1H was abolished by PAF stimulaiton to some extent. Moreover, XQ-1H or PAFR siRNA alleviated the neuronal pyroptosis induced by LPS and nigericin (an NLRP3 activator) in cortical neurons. Taken together, this study firstly demonstrates that PAFR is involved in neuronal pyroptosis after I/R injury, and XQ-1H, a specific PAFR inhibitor, has a promising prospect in attenuating I/R injury from the perspective of anti-pyroptosis.

Control of Neuroinflammation through Radiation-Induced Microglial Changes

Microglia, the innate immune cells of the central nervous system, play a pivotal role in the modulation of neuroinflammation. Neuroinflammation has been implicated in many diseases of the CNS, including Alzheimer's disease and Parkinson's disease. It is well documented that microglial activation, initiated by a variety of stressors, can trigger a potentially destructive neuroinflammatory response via the release of pro-inflammatory molecules, and reactive oxygen and nitrogen species. However, the potential anti-inflammatory and neuroprotective effects that microglia are also thought to exhibit have been under-investigated. The application of ionising radiation at different doses and dose schedules may reveal novel methods for the control of microglial response to stressors, potentially highlighting avenues for treatment of neuroinflammation associated CNS disorders, such as Alzheimer's disease and Parkinson's disease. There remains a need to characterise the response of microglia to radiation, particularly low dose ionising radiation.

In vivo assessment of molybdenum and cadmium co-induce nephrotoxicity via NLRP3/Caspase-1-mediated pyroptosis in ducks

Excessive molybdenum (Mo) and cadmium (Cd) cause toxic effects on animals, but their joint effects on pyroptosis in kidney of ducks remain unclear. 160 healthy 7-day-old ducks were randomly divided into four groups which were fed with basal diet containing different dosages of Mo or/and Cd for 16 weeks. On the 4th, 8th, 12th and 16th weeks, kidney tissue and serum were collected. The results showed that Mo or/and Cd could significantly elevate their contents in kidney, disturb the homeostasis of trace elements, cause renal function impairment and histological abnormality, and oxidative stress as accompanied by increasing hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations and decreasing glutathione peroxidase (GSH-Px), catalase (CAT) and total-superoxide dismutase (T-SOD) activities. Simultaneously, Mo or/and Cd could markedly increase interleukin-1β (IL-1β), interleukin-18 (IL-18) contents and the expression levels of pyroptosis-related genes (NOD-like receptor protein-3 (NLRP3), Caspase-1, apoptosis-associated speck-like protein (ASC), NIMA-related kinase 7 (NEK7), Gasdermin A (GSDMA), Gasdermin E (GSDME), IL-1β and IL-18) and proteins (NLRP3, Caspase-1 p20, ASC and Gasdermin D (GSDMD)). Moreover, the changes of above these indicators were more obvious in combined group. Taken together, the results illustrate that Mo and Cd might synergistically lead to oxidative stress and induce pyroptosis via NLRP3/Caspase-1 pathway, whose mechanism is somehow related to Mo and Cd accumulation in duck kidneys.

JNK inhibition alleviates delayed neurocognitive recovery after surgery by limiting microglia pyroptosis

Delayed neurocognitive recovery (dNCR) is a prevalent complication after surgery in older adults. Neuroinflammation plays a pivotal role in the pathogenesis of dNCR. Recently,compelling evidence suggests that theinvolvement of microglia pyroptosis in the regulation of neuroinflammation in neurologicaldiseases. Nevertheless, the exact role of microglia pyroptosis in dNCR remains elusive. In the study, in vitro and in vivo models of dNCR were used to examine the potential effects of the mitogen‑activated protein kinase signaling pathway on Nod-like receptor protein 3 (NLRP3) inflammasome-mediated microglia pyroptosis and cognitive deficits following surgery. In vivo, we observed surgery-induced upregulation of phosphorylated (p)-c-Jun N-terminal kinases (JNK) in microglia and subsequently NLRP3 inflammasome activation, pyroptosis, and inflammatory cytokines release in mice hippocampus. Interestingly, JNK inhibitor SP600125 significantly attenuated surgery-induced cognitive impairments through inhibiting pyroptosis, inflammatory responses, and reducing immunoreactivity of NLRP3 and gasdermin D N terminus (GSDMD-N) in hippocampal microglia. In vitro, NLRP3 inflammasome- and pyroptosis-associated proteins and immunoreactivity of NLRP3, GSDMD-N, and interleukin-1β were activated in BV2 microglial cells following lipopolysaccharide (LPS) stimulation. These effects were significantly suppressed in BV2 cells by SP600125 treatment. Furthermore, treatment with NLRP3 specific inhibitor, MCC950, attenuated microglia pyroptosis induced by LPS, but did not rescue LPS-induced increased expression of p-JNK. These results indicate that the JNK pathway is largely upstream of the NLRP3 inflammasome, which exerts a crucial regulatory impact on microglia pyroptosis and inflammatory responses, thus providing a promising avenue to prevent dNCR.

Protective genes and pathways in Alzheimer's disease: moving towards precision interventions

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder that is characterized by neurodegeneration, cognitive impairment, and an eventual inability to perform daily tasks. The etiology of Alzheimer's is complex, with numerous environmental and genetic factors contributing to the disease. Late-onset AD is highly heritable (60 to 80%), and over 40 risk loci for AD have been identified via large genome-wide association studies, most of which are common variants with small effect sizes. Although these discoveries have provided novel insight on biological contributors to AD, disease-modifying treatments remain elusive. Recently, the concepts of resistance to pathology and resilience against the downstream consequences of pathology have been of particular interest in the Alzheimer's field as studies continue to identify individuals who evade the pathology of the disease even into late life and individuals who have all of the neuropathological features of AD but evade downstream neurodegeneration and cognitive impairment. It has been hypothesized that a shift in focus from Alzheimer's risk to resilience presents an opportunity to uncover novel biological mechanisms of AD and to identify promising therapeutic targets for the disease. This review will highlight a selection of genes and variants that have been reported to confer protection from AD within the literature and will also discuss evidence for the biological underpinnings behind their protective effect with a focus on genes involved in lipid metabolism, cellular trafficking, endosomal and lysosomal function, synaptic function, and inflammation. Finally, we offer some recommendations in areas where the field can rapidly advance towards precision interventions that leverage the ideas of protection and resilience for the development of novel therapeutic strategies.

Advanced research on the regulated necrosis mechanism in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury is an important factor that seriously affects the prognosis of patients with myocardial infarction. It can cause myocardial stun, no-reflow phenomenon, reperfusion arrhythmia, and even irreversible cardiomyocyte death. Regulated necrosis is a newly discovered type of regulatory cell death that is different from apoptosis, including necroptosis, pyrolysis, iron death and other forms. Regulated necrosis plays an important role in myocardial infarction, heart failure and other cardiovascular diseases, as well as myocardial ischemia-reperfusion injury and other pathophysiological processes, and is expected to become a new target for intervention in this type of disease.

[Construction of macrophage RAW 264.7 cells with gsdmd gene knockout by CRISPR/Cas9 system]

OBJECTIVE

To construct a cell model of gsdmd gene knockout in macrophage RAW 264.7 cells using CRISPR/Cas9 system.

METHODS

Four specific single guide RNAs (sgRNAs) targeting gsdmd were designed to construct pGL3-sgRNA recombinant plasmids, which were identified by PCR amplification and sequencing.Cas9 and the recombinant plasmids were transfected into RAW 264.7 cells in two steps, and the cellular expression of cas9 was detected with real-time quantitative PCR (qPCR).The positive cell clones with gsdmd gene knockout were screened using puromycin and verified by sequencing and Western blotting.Annexin Ⅴ/PI staining and LDH release assay were performed in gsdmd-/-RAW 264.7 cells after being co-cultured with Salmonella Typhimurium.

RESULTS

qPCR results showed that cas9 gene was stably expressed in RAW 264.7-Cas9 cells (P< 0.01).PCR and sequencing results demonstrated successful construction of the recombinant plasmid pGL3-sgRNA. The results of PCR, sequencing and Western blotting all confirmed that gsdmd -/-RAW 264.7 cells were successfully constructed. Annexin Ⅴ/PI staining and LDH release assay showed that gsdmd gene knockout significantly inhibited macrophage death caused by S.Typhimurium infection (P < 0.01).

CONCLUSIONS

gsdmd -/-RAW 264.7 cells provide a cell model for studying the mechanisms underlying GSDMD-mediated macrophage death.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis alleviates excess molybdenum-induced apoptosis in duck renal tubular epithelial cells

OBJECTIVE

Excess molybdenum (Mo) is harmful to the body, and the kidney is the vital target organ for Mo exposure. This study focused on the impacts of excess Mo on pyroptosis and the relationship between pyroptosis and apoptosis in kidney.

METHODS

The duck renal tubular epithelial cells were treated with (NH₄)₆Mo₇O₂₄·4H₂O (0, 480, 720 and 960 μM Mo), N-acetyl-L-cysteine (NAC) (100 μM), Z-YVAD-fluoromethylketone (YVAD) (10 μM) and the combination of Mo and NAC or YVAD for 12 h. The LDH release and IL-1β, IL-18 contents of cell supernatant were detected by LDH and ELISA kits. The MMP and ROS level were measured using MMP and ROS kits by flow cytometry. The apoptotic rate of cell was detected by AO/EB counterstaining. Pyroptosis and apoptosis-related factors mRNA and protein levels were assayed by real-time qPCR and western blot, respectively.

RESULTS

Excessive Mo markedly increased LDH, IL-18, IL-1β releases and induced overproduction of ROS, pyroptosis-related factors mRNA and protein levels. NAC and YVAD dramatically decreased pyroptosis induced by Mo. Simultaneously, YVAD significantly changed apoptosis-related factors mRNA and protein levels, and reduced cell apoptotic rate.

CONCLUSION

Excessive Mo exposure can induce pyroptosis by the ROS/NLRP3/Caspase-1 pathway in duck renal tubular epithelial cells, and restraining pyroptosis of Caspase-1 dependence might weaken excess Mo-induced apoptosis. The study provides theoretical basis for excess Mo exposure nephrotoxic researches on waterfowl and the interplay between pyroptosis and apoptosis highlights a new sight into the mechanism of Mo-induced nephrotoxicity.