Endoplasmic reticulum stress related factor IRE1α regulates TXNIP/NLRP3-mediated pyroptosis in diabetic nephropathy

Emerging insights into the role of NLRP3 inflammasome and endoplasmic reticulum stress in renal diseases

NLRP3 inflammasome is a key component of the innate immune system, mediating the activation of caspase-1, and the maturity and secretion of the pro-inflammatory cytokine interleukin (IL)-1beta (IL-1β) and IL-18 to cope with microbial infections and cell injury. The NLRP3 inflammasome is activated by various endogenous danger signals, microorganisms and environmental stimuli, including urate, extracellular adenosine triphosphate (ATP) and cholesterol crystals. Increasing evidence indicates that the abnormal activation of NLRP3 is involved in multiple diseases including renal diseases. Hence, clarifying the mechanism of action of NLRP3 inflammasome in different diseases can help prevent and treat various diseases. Endoplasmic reticulum (ER) is an important organelle which participates in cell homeostasis maintenance and protein quality control. The unfolded protein response (UPR) and ER stress are caused by the excessive accumulation of unfolded or misfolded proteins in ER to recover ER homeostasis. Many factors can cause ER stress, including inflammation, hypoxia, environmental toxins, viral infections, glucose deficiency, changes in Ca2+ level and oxidative stress. The dysfunction of ER stress participates in multiple diseases, such as renal diseases. Many previous studies have shown that NLRP3 inflammasome and ER stress play an important role in renal diseases. However, the relevant mechanisms are not yet fully clear. Herein, we focus on the current understanding of the role and mechanism of ER stress and NLRP3 inflammasome in renal diseases, hoping to provide theoretical references for future related researches.

(+)-Catechin ameliorates diabetic nephropathy injury by inhibiting endoplasmic reticulum stress-related NLRP3-mediated inflammation

Endoplasmic reticulum (ER) stress and chronic sterile inflammation are associated with the pathogenesis of diabetic nephropathy (DN). Catechins are natural polyphenolic compounds found in green tea that possess some health benefits. However, whether (+)-catechin can reduce tubular injury in DN by regulating ER stress and NLRP3-associated inflammation remains uncertain. This study examined the effects of (+)-catechin on streptozotocin (STZ)-induced diabetic mice and on palmitic acid (PA)-treated HK-2 cells. In vivo, a DN mouse model was generated by injecting STZ. The biochemical indicators of serum and urine, as well as renal histopathology and ultrastructure were analysed. To predict the mechanisms associated with (+)-catechin, network pharmacology and molecular docking were used. Finally, quantitative real-time PCR (qPCR), western blot analysis and immunofluorescence analysis were performed to measure the mRNA and protein expressions of specific targets in the renal tissue of DN mice and PA-treated HK-2 cells to validate the predicted results. (+)-Catechin significantly ameliorated renal function and pathological changes associated with tubular injury by inhibiting ER stress by downregulating of GRP78, PEAK, CHOP, ATF6 and XBP1. In addition, (+)-catechin inhibited renal inflammation by suppressing NLRP3 associated inflammation, which was characterized by the downregulation of NLRP3, ASC, AIM2, Caspase1, IL-1β and IL-18 in DN mice and PA-treated HK-2 cells. Collectively, these findings suggested that (+)-catechin exerted a renoprotective effect against DN by inhibiting ER stress and NLRP3-related inflammation to ameliorate tubular injury, suggesting the therapeutic potential of (+)-catechin.

The roles of pyroptosis in genitourinary diseases

Pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, is thought to be closely associated with the pathogenesis of diseases. Recently, the association between pyroptosis and urinary diseases has attracted considerable attention, and a comprehensive review focusing on this issue is not available. In this study, we reviewed the role of pyroptosis in the development and progression of benign urinary diseases and urinary malignancies. Based on this, pyroptosis has been implicated in the development of urinary diseases. In summary, this review sheds light on future research directions and provides novel ideas for using pyroptosis as a powerful tool to fight urinary diseases.

Dapagliflozin prevents kidney podocytes pyroptosis via miR-155-5p/HO-1/NLRP3 axis modulation

Diabetic nephropathy (DN) is a significant clinical microvascular complication associated with diabetes mellitus (DM), and end-stage diabetes giving rise to kidney failure is developing into the major etiological factor of chronic kidney failure. Dapagliflozin is reported to limit podocyte damage in DM, which has proven to protect against renal failure. Mounting evidence has demonstrated that pyroptosis is associated with DM progression. Nevertheless, whether pyroptosis causes DN and the underlying molecular pathways remain obscure. In this study, we aimed to explore the antipyroptotic attributes of dapagliflozin and elucidate the underlying mechanisms of kidney damage in diabetes. In vivo, experiments were conducted in streptozotocin (STZ)-induced type 2 diabetic mice, which were administered dapagliflozin via gavage for 6 weeks. Subsequently, the specific organizational characteristics and expression of pyroptosis-related genes were evaluated. Intragastric dapagliflozin administration markedly reduced renal tissue injury. Meanwhile, dapagliflozin also attenuated the expression level of pyroptosis associated genes, including ASC, cleaved Caspase-1, GSDMD N-termini, NLRP3, IL-18, and IL-1β in renal tissue of dapagliflozin-treated animals. Similar antipyroptotic effects were observed in palmitic acid (PA)-treated mouse podocytes. We also found that heme oxygenase 1 (HO-1) enhanced the protection of mouse podocyte clone 5 cells (MPC5). Moreover, miR-155-5p inhibition increased pyroptosis in PA-treated MPC5 cells, suggesting that miR-155-5p acts as an endogenous stimulator that increases HO-1 expression and reduces pyroptosis. Hence, our findings imply that dapagliflozin inhibits podocyte pyroptosis via the miR-155-5p/HO-1/NLRP3 axis in DM. Furthermore, dapagliflozin substitution may be regarded as an effective strategy for preventing pyroptosis in the kidney, including a therapeutic option for treating pyroptosis-related DN.

Research progress of the effective active ingredients of Astragalus mongholicus in the treatment of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most prevalent consequences of diabetes, with a high incidence and disability rate. The DPN's pathogenesis is extremely complex and yet to be fully understood. Persistent high glucose metabolism, nerve growth factor deficiency, microvascular disease, oxidative stress, peripheral nerve cell apoptosis, immune factors, and other factors have been implicated in the pathogenesis of DPN. Astragalus mongholicus is a commonly used plant used to treat DPN in clinical settings. Its rich chemical components mainly include Astragalus polysaccharide, Astragalus saponins, Astragalus flavones, etc., which play a vital role in the treatment of DPN. This review aimed to summarize the pathogenesis of DPN and the studies on the mechanism of the effective components of Astragalus mongholicus in treating DPN. This is of great significance for the effective use of Chinese herbal medicine and the promotion of its status and influence on the world.

Autophagy, Pyroptosis and Ferroptosis are Rising Stars in the Pathogenesis of Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications in diabetes and can potentially develop into end-stage renal disease. Its pathogenesis is complex and not fully understood. Podocytes, glomerular endothelial cells (GECs), glomerular mesangial cells (GMCs) and renal tubular epithelial cells (TECs) play important roles in the normal function of glomerulus and renal tubules, and their injury is involved in the progression of DN. Although our understanding of the mechanisms leading to DN has substantially improved, we still need to find more effective therapeutic targets. Autophagy, pyroptosis and ferroptosis are programmed cell death processes that are associated with inflammation and are closely related to a variety of diseases. Recently, a growing number of studies have reported that autophagy, pyroptosis and ferroptosis regulate the function of podocytes, GECs, GMCs and TECs. This review highlights the contributions of autophagy, pyroptosis, and ferroptosis to DN injury in these cells, offering potential therapeutic targets for DN treatment.

GLP-1RAs inhibit the activation of the NLRP3 inflammasome signaling pathway to regulate mouse renal podocyte pyroptosis

OBJECTIVE

Podocytes are closely related to renal function as an important part of the glomerulus. The reduction and damage of podocytes lead to further decline of renal function and aggravate the progression of DKD. Glucagon-like peptide-1 receptor agonists (GLP-1RAS) have recently attracted great attention in improving podocyte dysfunction, but the specific mechanism remains uncertain.

METHODS

We used mouse kidney podocyte MPC5 to construct a high-glucose injury model. Cell viability was detected by the MTT method; RT-qPCR and western blotting were used to detect the expressions of NF-κB p65, NLRP3, GSDMD, N-GSDMD, caspase-1 and cleaved-caspase-1, and we used ELISA to detect the expressions of inflammatory factors IL-1β and IL-18.

RESULTS

Our results showed that high glucose decreased podocyte survival, while liraglutide and semaglutide increased podocyte survival under high glucose. Liraglutide and semaglutide can inhibit the expression of pyroptosis-related genes and proteins and also inhibit the expression of inflammatory factors IL-1β, IL-18 increase.

CONCLUSION

The protective effect of liraglutide and semaglutide on podocytes may be achieved by regulating the NLRP3 inflammasome pathway and inhibiting pyroptosis, and there were no significant differences between the two GLP-1RAs (liraglutide and semaglutide) in inhibiting podocyte pyroptosis.

Gypenoside XVII attenuates renal ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress and NLRP3 inflammasome-triggered pyroptosis

BACKGROUND

Renal ischemia-reperfusion (I/R) is one of the main causes of acute kidney injury (AKI), for which there is currently no effective treatment. Recently, the interaction between endoplasmic reticulum (ER) stress and pyroptosis during AKI has been investigated.

AIM

The purpose of this study was to investigate the protective effects of Gypenoside XVII (GP-17) against I/R-induced renal injury.

METHODS

In this study, mice were divided into 6 groups, sham group, I/R group, GP-17 low-, medium-, high-dose group, and positive control 4-PBA group. The renal I/R was performed in mice by clamping the bilateral renal pedicles for 40 min, and then reperfusing for 24 h. Blood and kidney samples were collected for analysis.

RESULTS

The results showed that GP-17 improved renal function and alleviated renal histopathological abnormalities caused by I/R. In addition, GP-17 pretreatment significantly decreased the expression or phosphorylation of ER stress response proteins including BIP, p-PERK, and CHOP. Besides, GP-17 inhibited the expression of pyroptosis proteins including caspase-1, GSDMD, and apoptotic protein BAX. The inflammatory factor IL-1β in these GP-17 pretreatment groups was also significantly reduced.

CONCLUSION

GP-17 blocked NLRP3 inflammasome activation by inhibiting ERS, thereby inhibiting renal tubular cell pyroptosis and apoptosis, and prevented renal I/R injury.

Adiponectin inhibits LPS-induced nucleus pulposus cell pyroptosis through the miR-135a-5p/TXNIP signaling pathway

Pyroptosis, a newly discovered programmed cell death process, is characterized by NLRP3 inflammasome activation and pro-inflammatory mediator release. Nucleus pulposus (NP) cell pyroptosis is an important cause of intervertebral disc degeneration (IDD). Adiponectin (APN) is an adipokine and has an anti-inflammatory effect. However, whether and how APN protects against NP cell pyroptosis remains unexplored. Our results showed that human degenerated NP tissue displayed a significant increase in the protein levels of NLRP3, caspase-1 and GSDMD-N. APN expression was down-regulated in human degenerated NP tissue and NP cells challenged with lipopolysaccharide (LPS). Lentivirus-mediated overexpression of APN increased miR-135a-5p levels, decreased thioredoxin-interacting protein (TXNIP) expression and its interaction with NLRP3, and inhibited pyroptosis in human NP cells stimulated with LPS. TXNIP was identified as a direct target of miR-135a-5p. The inhibitory effects of APN on pyroptosis were reversed by pretreatment with miR-135a-5p inhibitor or lentiviral vector expressing TXNIP in LPS-treated human NP cells. In summary, these data suggest that APN restrains LPS-induced pyroptosis through the miR-135a-5p/TXNIP signaling pathway in human NP cells. Increasing APN levels could be a new approach to retard IDD.

Resveratrol improves emamectin benzoate-induced pyroptosis and inflammation of Ctenopharyngodon idellus hepatic cells by alleviating oxidative stress/endoplasmic reticulum stress

Emamectin benzoate (EMB) is the most widely used pesticide in the world and contributes to water pollution. Owing to the lack of a specific antidote, EMB has a severe negative impact on the health of aquatic organisms. Resveratrol (RES), a substance with antioxidant capacity, is secreted by the fruits of many plants. This study was to explore the protection of RES against EMB-induced pyroptosis and inflammatory response in grass carp (Ctenopharyngodon idellus) hepatic liver (L8824) cells by oxidative stress/endoplasmic reticulum (ER) stress. The results showed that compared to the CON group, EMB induced oxidative stress in L8824 cells with the increase of reactive oxygen species (ROS), methane dicarboxylic aldehyde (MDA), and hydrogen peroxide (H2O2) contents and the decrease of total superoxide dismutase (t-sod) and glutathione peroxidase (gsh-px) activities (P < 0.05). In addition, EMB triggered ERS, increasing the relative mRNA expression of protein kinase R-like endoplasmic reticulum kinase (perk), inositol requiring enzyme 1 alpha (ire1α), glucose-regulated protein 78 (grp78), activating transcription factor 4 (atf4), activating transcription factor 6 (atf6), and CCAAT-enhancer-binding protein homologous protein (chop) and the protein expression of eukaryotic initiation factor 2α (eif2α), chop, atf6, and atf4. Meanwhile, EMB further induced pyroptosis by upregulating the mRNA and protein expression of nlrp3, aptamer protein (asc), caspase-1, gsdmd, interleukin-1β (il-1β), and interleukin-18 (il-18). EMB also induced inflammation in L8824 cells by increasing the mRNA expression of interleukin-2 (il-2), interleukin-6 (il-6), tumor necrosis factor-α (tnf-α), and ifn-γ and decreasing the content of interleukin-10 (il-10). However, compared to the EMB group, the oxidant indices and expression of genes related to ER stress, pyroptosis, and pro-inflammatory factors were significantly down-regulated (P < 0.05), whereas the antioxidant indicators and anti-inflammatory factor were significantly up-regulated in the EMB + RES group (P < 0.05). In conclusion, EMB caused hepatocytes pyroptosis and inflammation in grass carp, and RES could alleviate EMB-induced pyroptosis and inflammation in L8824 cells by ameliorating oxidative stress/ER stress.

N6-methyladenosine methylation regulator RBM15 promotes the progression of diabetic nephropathy by regulating cell proliferation, inflammation, oxidative stress, and pyroptosis through activating the AGE-RAGE pathway

BACKGROUND

Diabetic nephropathy (DN) is a major cause of end-stage renal disease throughout the world, and m6A modification plays a critical role in the progression of DN. We aimed to find m6A-related genes and their regulatory mechanisms in DN.

METHODS

The expression levels of four important m6A-related genes (METTL16, RBM15, IGF2BP1, and ALKBH5) were detected by quantitative real-time PCR (RT-qPCR). RBM15 was chosen and its function was explored. The downstream pathway of RBM15 was screened by transcriptome sequencing. The levels of AGE, inflammation, and oxidative stress were determined with enzyme-linked immunosorbent assay, and the expression of AGE-RAGE pathway-related proteins were detected by Western blot (WB). Cell proliferation was assessed by Cell counting Kit-8 (CCK-8). The levels of pyroptosis-related proteins were evaluated by RT-qPCR or WB.

RESULTS

METTL16 and RBM15 were up regulated in the mouse model of DN, in which RBM15 was more significant. Silencing RBM15 recovered cell proliferation, reduced the levels of inflammation factors, and inhibited cell pyroptosis in high glucose-induced HK-2 cells. Transcriptome sequencing suggested that the AGE-RAGE pathway might be downstream of RBM15. RBM15 knockdown reduced AGE level and the expression of AGE-RAGE pathway-related proteins. After silencing RBM15, we found that activating the AGE-RAGE pathway inhibited cell proliferation, increased the levels of inflammation factors, promoted oxidative stress, and induced cell pyroptosis in HK-2 cell model of DN.

CONCLUSION

The m6A-related gene RBM15 inhibited cell proliferation, promoted inflammation, oxidative stress, and cell pyroptosis, thereby facilitating the progression of DN through the activation of the AGE-RAGE pathway.

Co-exposure of avermectin and imidacloprid induces DNA damage, pyroptosis, and immune dysfunction in epithelioma papulosum cyprini cells via ROS-mediated Keap1/Nrf2/TXNIP axis

Pesticide mixtures can reduce pest resistance, however, their overuse severely threatens aquatic animal survival and public health. Avermectin (AVM) and imidacloprid (IMI) are potent insecticides often employed in agriculture. By inducing oxidative stress, these chemicals can induce cell death. Here, we evaluated the combined toxicity of AVM and IMI on EPC cells based on the concept of toxicity units (TU). We established EPC cell models exposed to AVM and IMI alone and in combination. The results showed that AVM and IMI had additive effects on the toxicity of EPC cells. Meanwhile, the co-exposure of AVM and IMI exacerbated oxidative stress and induced excessive production of reactive oxygen species (ROS), triggered Keap1/Nrf2/TXNIP axis, caused DNA damage and increased the expression of genes related to pyroptosis. In addition, co-exposure to AVM and IMI caused immunosuppression of EPC cells. The ROS inhibitor N-Acetyl-l-cysteine (NAC) can dramatically reverse these alterations brought on by AVM and IMI co-exposure. The findings above conclude that co-exposure to AVM and IMI causes DNA damage, pyroptosis, and immunosuppression in EPC cells through the ROS-mediated Keap1/Nrf2/TXNIP pathway. This study revealed the joint toxicity of AVM and IMI on EPC cells, and reminded people to consider its impact on aquatic animals when using pesticide mixtures.

Identification of pyroptosis-related genes and potential drugs in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is one of the serious microvascular complications of diabetes mellitus (DM). A growing body of research has demonstrated that the inflammatory state plays a critical role in the incidence and development of DN. Pyroptosis is a new way of programmed cell death, which has the particularity of natural immune inflammation. The inhibition of inflammatory cytokine expression and regulation of pathways related to pyroptosis may be a novel strategy for DN treatment. The aim of this study is to identify pyroptosis-related genes and potential drugs for DN.

METHODS

DN differentially expressed pyroptosis-related genes were identified via bioinformatic analysis Gene Expression Omnibus (GEO) dataset GSE96804. Dataset GSE30528 and GSE142025 were downloaded to verify pyroptosis-related differentially expressed genes (DEGs). Least absolute shrinkage and selection operator (LASSO) regression analysis was used to construct a pyroptosis-related gene predictive model. A consensus clustering analysis was performed to identify pyroptosis-related DN subtypes. Subsequently, Gene Set Variation Analysis (GSVA), Gene Ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to explore the differences between DN clusters. A protein-protein interaction (PPI) network was used to select hub genes and DGIdb database was utilized to screen potential therapeutic drugs/compounds targeting hub genes.

RESULTS

A total of 24 differentially expressed pyroptosis-related genes were identified in DN. A 16 gene predictive model was conducted via LASSO regression analysis. According to the expression level of these 16 genes, DN cases were divided into two subtypes, and the subtypes are mainly associated with inflammation, activation of immune response and cell metabolism. In addition, we identified 10 hub genes among these subtypes, and predicted 65 potential DN therapeutics that target key genes.

CONCLUSION

We identified two pyroptosis-related DN clusters and 65 potential therapeutical agents/compounds for DN, which might shed a light on the treatment of DN.

The role of Chinese herbal medicine in the treatment of diabetic nephropathy by regulating endoplasmic reticulum stress

Diabetic nephropathy (DN), a prevalent microvascular complication of diabetes mellitus, is the primary contributor to end-stage renal disease in developed countries. Existing clinical interventions for DN encompass lifestyle modifications, blood glucose regulation, blood pressure reduction, lipid management, and avoidance of nephrotoxic medications. Despite these measures, a significant number of patients progress to end-stage renal disease, underscoring the need for additional therapeutic strategies. The endoplasmic reticulum (ER) stress response, a cellular defense mechanism in eukaryotic cells, has been implicated in DN pathogenesis. Moderate ER stress can enhance cell survival, whereas severe or prolonged ER stress may trigger apoptosis. As such, the role of ER stress in DN presents a potential avenue for therapeutic modulation. Chinese herbal medicine, a staple in Chinese healthcare, has emerged as a promising intervention for DN. Existing research suggests that some herbal remedies may confer renoprotective benefits through the modulation of ER stress. This review explores the involvement of ER stress in the pathogenesis of DN and the advancements in Chinese herbal medicine for ER stress regulation, aiming to inspire new clinical strategies for the prevention and management of DN.

Comprehensive analysis of endoplasmic reticulum stress-related mechanisms in type 2 diabetes mellitus

BACKGROUND

The endoplasmic reticulum (ER) is closely related to a wide range of cellular functions and is a key component to maintain and restore metabolic health. Type 2 diabetes mellitus (T2DM) is a serious threat to human health, but the ER stress (ERS)-related mechanisms in T2DM have not been fully elucidated.

AIM

To identify potential ERS-related mechanisms and crucial biomarkers in T2DM.

METHODS

We conducted gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) in myoblast and myotube form GSE166502, and obtained the differentially expressed genes (DEGs). After intersecting with ERS-related genes, we obtained ERS-related DEGs. Finally, functional analyses, immune infiltration, and several networks were established.

RESULTS

Through GSEA and GSVA, we identified several metabolic and immune-related pathways. We obtained 227 ERS-related DEGs and constructed several important networks that help to understand the mechanisms and treatment of T2DM. Finally, memory CD4⁺ T cells accounted for the largest proportion of immune cells.

CONCLUSION

This study revealed ERS-related mechanisms in T2DM, which might contribute to new ideas and insights into the mechanisms and treatment of T2DM.

Endoplasmic reticulum stress in diabetic kidney disease: adaptation and apoptosis after three UPR pathways

Diabetes kidney disease (DKD) is one of the common chronic microvascular complications of diabetes, which has become the most important cause of modern chronic kidney disease beyond chronic glomerulonephritis. The endoplasmic reticulum is one of the largest organelles, and endoplasmic reticulum stress (ERS) is the basic mechanism of metabolic disorder in all organs and tissues. Under the stimulation of stress-induced factors, the endoplasmic reticulum, as a trophic receptor, regulates adaptive and apoptotic ERS through molecular chaperones and three unfolded protein reaction (UPR) pathways, thereby regulating diabetic renal damage. Therefore, three pathway factors have different expressions in different sections of renal tissues. This study deeply discussed the specific reagents, animals, cells, and clinical models related to ERS in DKD, and reviewed ERS-related three pathways on DKD with glomerular filtration membrane, renal tubular reabsorption, and other pathological lesions of different renal tissues, as well as the molecular biological mechanisms related to the balance of adaption and apoptosis by searching and sorting out MeSH subject words from PubMed database.

A Novel Defined PANoptosis-Related miRNA Signature for Predicting the Prognosis and Immune Characteristics in Clear Cell Renal Cell Carcinoma: A miRNA Signature for the Prognosis of ccRCC

Clear cell renal cell carcinoma (ccRCC) is one of the most prevalent cancers, and PANoptosis is a distinct, inflammatory-programmed cell death regulated by the PANoptosome. The essential regulators of cancer occurrence and progression are microRNAs (miRNAs). However, the potential function of PANoptosis-related microRNAs (PRMs) in ccRCC remains obscure. This study retrieved ccRCC samples from The Cancer Genome Atlas database and three Gene Expression Omnibus datasets. PRMs were recognized based on previous reports in the scientific literature. Regression analyses were used to identify the prognosis PRMs and construct a PANoptosis-related miRNA prognostic signature based on the risk score. We discovered that high-risk patients had poorer survival prognoses and were significantly linked to high-grade and advanced-stage tumors, using a variety of R software packages and web analysis tools. Furthermore, we demonstrated that the low-risk group had significant changes in their metabolic pathways. In contrast, the high-risk group was characterized by high immune cell infiltration, immune checkpoint expression, and low half-maximum inhibition concentration (IC50) values of chemotherapeutic agents. This suggests that high-risk patients may benefit more from immunotherapy and chemotherapy. In conclusion, we constructed a PANoptosis-related microRNA signature and revealed its potential significance in clinicopathological features and tumor immunity, thereby providing new precise treatment strategies.

Glutamine inhibits inflammation, oxidative stress, and apoptosis and ameliorates hyperoxic lung injury

Glutamine (Gln) is the most widely acting and abundant amino acid in the body and has anti-inflammatory properties, regulates body metabolism, and improves immune function. However, the mechanism of Gln's effect on hyperoxic lung injury in neonatal rats is unclear. Therefore, this work focused on examining Gln's function in lung injury of newborn rats mediated by hyperoxia and the underlying mechanism. We examined body mass and ratio of wet-to-dry lung tissue weights of neonatal rats. Hematoxylin and eosin (HE) staining was performed to examine histopathological alterations of lung tissues. In addition, enzyme-linked immunoassay (ELISA) was conducted to measure pro-inflammatory cytokine levels within bronchoalveolar lavage fluid (BALF). Apoptosis of lung tissues was observed using TUNEL assay. Western blotting was performed for detecting endoplasmic reticulum stress (ERS)-associated protein levels. The results showed that Gln promoted body weight gain, significantly reduced pathological damage and oxidative stress in lung tissue, and improved lung function in neonatal rats. Gln reduced pro-inflammatory cytokine release as well as inflammatory cell production in BALF and inhibited apoptosis in lung tissue cells. Furthermore, we found that Gln could downregulate ERS-associated protein levels (GRP78, Caspase-12, CHOP) and inhibit c-Jun N-terminal kinase (JNK) and inositol-requiring enzyme 1 alpha (IRE1α) phosphorylation. These results in an animal model of bronchopulmonary dysplasia (BPD) suggest that Gln may have a therapeutic effect on BPD by reducing lung inflammation, oxidative stress, and apoptosis and improving lung function; its mechanism of action may be related to the inhibition of the IRE1α/JNK pathway.

Natural products in attenuating renal inflammation via inhibiting the NLRP3 inflammasome in diabetic kidney disease

Diabetic kidney disease (DKD) is a prevalent and severe complications of diabetes and serves as the primary cause of end-stage kidney disease (ESKD) globally. Increasing evidence indicates that renal inflammation is critical in the pathogenesis of DKD. The nucleotide - binding oligomerization domain (NOD) - like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most extensively researched inflammasome complex and is considered a crucial regulator in the pathogenesis of DKD. The activation of NLRP3 inflammasome is regulated by various signaling pathways, including NF- κB, thioredoxin-interacting protein (TXNIP), and non-coding RNAs (ncRNA), among others. Natural products are chemicals extracted from living organisms in nature, and they typically possess pharmacological and biological activities. They are invaluable sources for drug design and development. Research has demonstrated that many natural products can alleviate DKD by targeting the NLRP3 inflammasome. In this review, we highlight the role of the NLRP3 inflammasome in DKD, and the pathways by which natural products fight against DKD via inhibiting the NLRP3 inflammasome activation, so as to provide novel insights for the treatment of DKD.

Role of microRNAs in programmed cell death in renal diseases: A review

MicroRNAs (miRNAs) regulate gene expression involving kidney morphogenesis and cell proliferation, apoptosis, differentiation, migration, invasion, immune evasion, and extracellular matrix remodeling. Programmed cell death (PCD) is mediated and regulated by specific genes and a wealth of miRNAs, which participate in various pathological processes. Dysregulation of miRNAs can disrupt renal development and induce the onset and progression of various renal diseases. An in-depth understanding of how miRNAs regulate renal development and diseases is indispensable to comprehending how they can be used in new diagnostic and therapeutic approaches. However, the mechanisms are still insufficiently investigated. Hence, we review the current roles of miRNA-related signaling pathways and recent advances in PCD research and aim to display the potential crosstalk between miRNAs and PCD. The prospects of miRNAs as novel biomarkers and therapeutic targets are also described, which might provide some novel ideas for further studies.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

Endoplasmic Reticulum Stress in Elderly Patients with COVID-19: Potential of Melatonin Treatment

Aging processes, including immunosenescence, inflammation, inflammasome formation, genomic instability, telomeric attrition, and altered autophagy, are involved in viral infections and they may contribute to increased pathophysiological responses to the SARS-CoV-2 infection in the elderly; this poses additional risks of accelerated aging, which could be found even after recovery. Aging is associated with oxidative damage. Moreover, SARS-CoV-2 infections may increase the production of reactive oxygen species and such infections will disturb the Ca++ balance via an endoplasmic reticulum (ER) stress-mediated unfolded protein response. Although vaccine development and anti-inflammation therapy lower the severity of COVID-19, the prevalence and mortality rates are still alarming in some countries worldwide. In this review, we describe the involvement of viral proteins in activating ER stress transducers and their downstream signals and in inducing inflammation and inflammasome formation. Furthermore, we propose the potential of melatonin as an ER stress modulator, owing to its antioxidant, anti-inflammatory, and immunoregulatory effects in viral infections. Considering its strong safety profile, we suggest that additive melatonin supplementation in the elderly could be beneficial in treating COVID-19.

The Role of NLRP3 Inflammasome in IgA Nephropathy

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerular disease worldwide today. The NLRP3 inflammasome is a polyprotein complex and an important participant in inflammation. Accumulating studies have shown that the NLRP3 inflammasome participates in a variety of kidney diseases, including IgAN. This review focuses on the role of the NLRP3 inflammasome in IgAN and summarizes multiple involved pathways, which may provide novel treatments for IgAN treatment.

Endoplasmic reticulum stress-mediated cell death in liver injury

The endoplasmic reticulum is an important intracellular organelle that plays an important role in maintaining cellular homeostasis. Endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) are induced when the body is exposed to adverse external stimuli. It has been established that ERS can induce different cell death modes, including autophagy, apoptosis, ferroptosis, and pyroptosis, through three major transmembrane receptors on the ER membrane, including inositol requirement enzyme 1α, protein kinase-like endoplasmic reticulum kinase and activating transcription factor 6. These different modes of cell death play an important role in the occurrence and development of various diseases, such as neurodegenerative diseases, inflammation, metabolic diseases, and liver injury. As the largest metabolic organ, the liver is rich in enzymes, carries out different functions such as metabolism and secretion, and is the body's main site of protein synthesis. Accordingly, a well-developed endoplasmic reticulum system is present in hepatocytes to help the liver perform its physiological functions. Current evidence suggests that ERS is closely related to different stages of liver injury, and the death of hepatocytes caused by ERS may be key in liver injury. In addition, an increasing body of evidence suggests that modulating ERS has great potential for treating the liver injury. This article provided a comprehensive overview of the relationship between ERS and four types of cell death. Moreover, we discussed the mechanism of ERS and UPR in different liver injuries and their potential therapeutic strategies.

The functions of IRE1α in neurodegenerative diseases: Beyond ER stress

Inositol-requiring enzyme 1 α (IRE1α) is a type I transmembrane protein that resides in the endoplasmic reticulum (ER). IRE1α, which is the primary sensor of ER stress, has been proven to maintain intracellular protein homeostasis by activating X-box binding protein 1 (XBP1). Further studies have revealed novel physiological functions of the IRE1α, such as its roles in mRNA and protein degradation, inflammation, immunity, cell proliferation and cell death. Therefore, the function of IRE1α is not limited to its role in ER stress; IRE1α is also important for regulating other processes related to cellular physiology. Furthermore, IRE1α plays a key role in neurodegenerative diseases that are caused by the phosphorylation of Tau protein, the accumulation of α-synuclein (α-syn) and the toxic effects of mutant Huntingtin (mHtt). Therefore, targeting IRE1α is a valuable approach for treating neurodegenerative diseases and regulating cell functions. This review discusses the role of IRE1α in different cellular processes, and emphasizes the importance of IRE1α in neurodegenerative diseases.

Novel lncRNA-prader willi/angelman region RNA, SNRPN neighbour (PWARSN) aggravates tubular epithelial cell pyroptosis by regulating TXNIP via dual way in diabetic kidney disease

OBJECTIVES

Elevated thioredoxin-interacting protein (TXNIP)-induced pyroptosis contributes to the pathology of diabetic kidney disease (DKD). However, the molecular mechanisms in dysregulated TXNIP in DKD remain largely unclear.

MATERIALS AND METHODS

Transcriptomic analysis identified a novel long noncoding RNA-Prader Willi/Angelman region RNA, SNRPN neighbour (PWARSN)-which was highly expressed in a proximal tubular epithelial cell (PTEC) under high glucose conditions. We focused on revealing the functions of PWARSN in regulating TXNIP-mediated pyroptosis in PTECs by targeting PWARSN expression via lentivirus-mediated overexpression and CRISPR-Cas9-based knockout in vitro and overexpressing PWARSN in the renal cortex by AAV-9 targeted injection in vivo. A number of molecular techniques disclosed the mechanisms of PWARSN in regulating TXNIP induced-pyroptosis in DKD.

RESULTS

TXNIP-NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and PTEC pyroptosis were activated in the renal tubules of patients with DKD and in diabetic mice. Then we explored that PWARSN enhanced TXNIP-driven PTECs pyroptosis in vitro and in vivo. Mechanistically, cytoplasmic PWARSN sponged miR-372-3p to promote TXNIP expression. Moreover, nuclear PWARSN interacted and facilitated RNA binding motif protein X-linked (RBMX) degradation through ubiquitination, resulting in the initiation of TXNIP transcription by reducing H3K9me3-enrichment at the TXNIP promoter. Further analysis indicated that PWARSN might be a potential biomarker for DKD.

CONCLUSIONS

These findings illustrate distinct dual molecular mechanisms for PWARSN-modulated TXNIP and PTECs pyroptosis in DKD, presenting PWARSN as a promising therapeutic target for DKD.

NLRP3-mediated pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN) is the main cause of end-stage renal disease (ESRD), which is characterized by a series of abnormal changes such as glomerulosclerosis, podocyte loss, renal tubular atrophy and excessive deposition of extracellular matrix. Simultaneously, the occurrence of inflammatory reaction can promote the aggravation of DN-induced kidney injury. The most important processes in the canonical inflammasome pathway are inflammasome activation and membrane pore formation mediated by gasdermin family. Converging studies shows that pyroptosis can occur in renal intrinsic cells and participate in the development of DN, and its activation mechanism involves a variety of signaling pathways. Meanwhile, the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome can not only lead to the occurrence of inflammatory response, but also induce pyroptosis. In addition, a number of drugs targeting pyroptosis-associated proteins have been shown to have potential for treating DN. Consequently, the pathogenesis of pyroptosis and several possible activation pathways of NLRP3 inflammasome were reviewed, and the potential drugs used to treat pyroptosis in DN were summarized in this review. Although relevant studies are still not thorough and comprehensive, these findings still have certain reference value for the understanding, treatment and prognosis of DN.

Aucubin ameliorates liver fibrosis and hepatic stellate cells activation in diabetic mice via inhibiting ER stress-mediated IRE1α/TXNIP/NLRP3 inflammasome through NOX4/ROS pathway

Type 2 diabetes (T2DM) is closely associated with hepatic injury, which could promote/exacerbate hepatic inflammation, steatosis, and accelerate liver fibrosis progression. Aucubin (AU), as an active ingredient isolated from Eucommia ulmoides, exists a nutritional value in hepatoprotective effect and diabetic complications. However, whether it possesses more outstanding features on improving liver injury in diabetic conditions and the underlying mechanism is unclear. Our research investigated the treatment of AU on liver fibrosis and potential mechanisms on high-fat diet/streptozotocin-induced diabetic mice and high glucose (HG)&TGF-β1-induced LX-2 cells. Results showed that AU restored hepatic function without affecting blood sugar levels in diabetic mice. Meanwhile, the enhanced levels of total cholesterol, triglycerides, and LDL-c were reversed in hepatic tissue after AU treatment. Histomorphology assays including H&E, Masson, PAS, Oil red and Sirius red staining showed that AU treatment reduced liver swelling, steatosis and fibrosis. Mechanistic studies showed that AU alleviated NLRP3 inflammasome activation and inflammatory responses via inhibiting ER stress-mediated IRE1α/TXNIP signaling pathway, which could postpone the development of T2DM induced hepatic fibrosis. In addition, the ROS generation and the up-regulated expression of NADHP oxidase 4 (NOX4) in the liver tissue were suppressed by AU treatment. Moreover, in vitro model, NOX4 activation was prominently enhanced and AU treatment blocked HG&TGF-β1-induced NOX4 derived superoxide generation and thereby ameliorating hepatic stellate cell activation, which can be abrogated in the overexpression of NOX4 LX-2 cells. In addition, inhibition effects on ER stress-mediated IRE1α/TXNIP/NLRP3 inflammasome by AU treatment also were abolished in the overexpression of NOX4 LX-2 cells. Meanwhile, molecular docking results indicated that AU and NOX4 protein have a higher affinity. Taken together, AU might be a potential nutraceutical or therapeutic drug to ameliorate hepatic impairment and fibrosis in T2DM.

Bexarotene-induced cell death in ovarian cancer cells through Caspase-4-gasdermin E mediated pyroptosis

Bexarotene selectively activates retinoid X receptor, which is a commonly used anticancer agent for cutaneous T-cell lymphoma. In this study, we aimed to investigate the anticancer effect of bexarotene and its underlying mechanism in ovarian cancer in vitro. The ES2 and NIH:OVACAR3 ovarian cancer cell lines were treated with 0, 5, 10, or 20 µM of bexarotene. After 24 h, cell number measurement and lactate dehydrogenase (LDH) cytotoxicity assay were performed. The effect of bexarotene on CDKN1A expression, cell cycle-related protein, cell cycle, pyroptosis, and apoptosis was evaluated. Bexarotene reduced cell proliferation in all concentrations in both the cells. At concentrations of > 10 µM, extracellular LDH activity increased with cell rupture. Treatment using 10 µM of bexarotene increased CDKN1A mRNA levels, decreased cell cycle-related protein expression, and increased the sub-G1 cell population in both cells. In ES2 cells, caspase-4 and GSDME were activated, whereas caspase-3 was not, indicating that bexarotene-induced cell death might be pyroptosis. A clinical setting concentration of bexarotene induced cell death through caspase-4-mediated pyroptosis in ovarian cancer cell lines. Thus, bexarotene may serve as a novel therapeutic agent for ovarian cancer.

The Role of the NLRP3 Inflammasome in Mediating Glomerular and Tubular Injury in Diabetic Nephropathy

The NOD-like receptor protein 3 (NLRP3) inflammasome is a multi-protein signalling complex integral to the chronic inflammatory response, activated in response to sterile and non-sterile cellular damage. The assembly and activation of the NLRP3 inflammasome comprise a two-step process involving nuclear factor kappa B (NFkB)-mediated priming, followed by canonical, non-canonical or alternative signalling pathways. These result in the maturation and release of inflammatory cytokines interleukin 1 beta (IL1ß) and interleukin-18 (IL18), which are associated with chronic inflammatory conditions including diabetic kidney disease. Diabetic nephropathy is a condition affecting ∼40% of people with diabetes, the key underlying pathology of which is tubulointerstitial inflammation and fibrosis. There is growing evidence to suggest the involvement of the NLRP3 inflammasome in this chronic inflammation. Early deterioration of kidney function begins in the glomerulus, with tubular inflammation dictating the progression of late-stage disease. Priming and activation of the NLRP3 inflammasome have been linked to several clinical markers of nephropathy including proteinuria and albuminuria, in addition to morphological changes including mesangial expansion. Treatment options for diabetic nephropathy are limited, and research that examines the impact of directly targeting the NLRP3 inflammasome, or associated downstream components are beginning to gain favour, with several agents currently in clinical trials. This review will explore a role for NLRP3 inflammasome activation and signalling in mediating inflammation in diabetic nephropathy, specifically in the glomerulus and proximal tubule, before briefly describing the current position of therapeutic research in this field.

Icariin attenuates ischemic stroke through suppressing inflammation mediated by endoplasmic reticulum stress signaling pathway in rats

Ischemic stroke possesses the characteristics of high incidence, high disability, and high mortality. Icariin (ICA) is a flavonoid extracted from the traditional Chinese medicine Epimedium. The protective effect of ICA on ischemic stroke is worthy to be further studied. In this study, male Sprague-Dawley rats were randomly divided into the following seven groups: sham, model, ICA low-dose (10 mg/kg), ICA medium-dose (20 mg/kg), ICA high-dose (40 mg/kg), positive control drug (12 mg/kg nimodipine) and endoplasmic reticulum stress induction (0.16 mg/kg tunicamycin) groups. The model of cerebral ischemia-reperfusion injury in the rats, including 2 h ischemia and 24 h reperfusion, was accomplished by applying the method of transient middle cerebral artery occlusion (MCAO). At 24 h reperfusion, neurological deficits, brain water content, pathological damage of brain tissues, the expression of inflammation-related targets, and the signal pathway-related proteins were explored. Compared with the model group, ICA significantly improved neurological deficits, brain edema and pathological damage after MCAO. In addition, ICA increased neuron survival, reduced microglial activation and expression of IL-1β, alleviating the inflammatory damage caused by ischemic stroke. Moreover, ICA suppressed the expressions of glucose-regulated protein 78 (GRP78), inositol requiring enzyme-1 α (IRE1α), phospho-IRE1α (p-IRE1α), protein kinase RNA-like ER kinase (PERK), phospho-PERK (p-PERK), spliced XBP1 (XBP1s), unspliced XBP1 (XBP1u), thioredoxin-interacting protein (TXNIP), NLRP3, and caspase-1. These results suggested that ICA offers neuroprotection against ischemic stroke by inhibiting ER stress-mediated inflammation. This article is protected by copyright. All rights reserved.

Long noncoding RNA X-inactive specific transcript regulates NLR family pyrin domain containing 3/caspase-1-mediated pyroptosis in diabetic nephropathy

BACKGROUND

NLRP3-mediated pyroptosis is recognized as an essential modulator of renal disease pathology. Long noncoding RNAs (lncRNAs) are active participators of diabetic nephropathy (DN). X inactive specific transcript (XIST) expression has been reported to be elevated in the serum of DN patients.

AIM

To evaluate the mechanism of lncRNA XIST in renal tubular epithelial cell (RTEC) pyroptosis in DN.

METHODS

A DN rat model was established through streptozotocin injection, and XIST was knocked down by tail vein injection of the lentivirus LV sh-XIST. Renal metabolic and biochemical indices were detected, and pathological changes in the renal tissue were assessed. The expression of indicators related to inflammation and pyroptosis was also detected. High glucose (HG) was used to treat HK2 cells, and cell viability and lactate dehydrogenase (LDH) activity were detected after silencing XIST. The subcellular localization and downstream mechanism of XIST were investigated. Finally, a rescue experiment was carried out to verify that XIST regulates NLR family pyrin domain containing 3 (NLRP3)/caspase-1-mediated RTEC pyroptosis through the microRNA-15-5p (miR-15b-5p)/Toll-like receptor 4 (TLR4) axis.

RESULTS

XIST was highly expressed in the DN models. XIST silencing improved renal metabolism and biochemical indices and mitigated renal injury. The expression of inflammation and pyroptosis indicators was significantly increased in DN rats and HG-treated HK2 cells; cell viability was decreased and LDH activity was increased after HG treatment. Silencing XIST inhibited RTEC pyroptosis by inhibiting NLRP3/caspase-1. Mechanistically, XIST sponged miR-15b-5p to regulate TLR4. Silencing XIST inhibited TLR4 by promoting miR-15b-5p. miR-15b-5p inhibition or TLR4 overexpression averted the inhibitory effect of silencing XIST on HG-induced RTEC pyroptosis.

CONCLUSION

Silencing XIST inhibits TLR4 by upregulating miR-15b-5p and ultimately inhibits renal injury in DN by inhibiting NLRP3/caspase-1-mediated RTEC pyroptosis.

MiR-1656 targets GPX4 to trigger pyroptosis in broilers kidney tissues by activating NLRP3 inflammasome under Se deficiency

Selenium (Se) is a vital minor element for the organism. Se deficiency caused inflammation in kidney tissue and regulate the expression of selenoproteins and microRNAs (miRNAs). Pyroptosis involved in the inflammatory response, however, whether microRNA targets GPX4 to regulate Se-deficient kidney tissue pyroptosis is unclear. In this study, broilers were divided into two groups, Control group with 0.3mg/kg Se diet and Se-deficient group with 0.03mg/kg Se diet. The dual luciferase reporter assay system and quantitative real-time PCR (qRT-PCR) were used to screen the specificity of miR-1656 and its target protein in Se-deficient broilers. We tested the pyroptosis-related genes of Se-deficient broilers kidney and miR-1656-transfected primary broilers kidney by qRT-PCR, Western blot (WB) and immunofluorescence staining. Our research indicated that the GPX4 is one of the target genes of miR-1656, and Se deficiency leaded to the overexpression of miR-1656 and the increased expression of pyroptosis-related genes. The overexpression of miR-1656 can induce increased expression of pyroptosis-related genes including NLRP3, Caspase-1, IL-18, and IL-1β by inhibiting the release of GPX4. This study showed that miR-1656 could increase the release of ROS by targeting GPX4, activated the NLRP3 inflammasome, and release the inflammatory factors IL-1β and IL-18 to trigger pyroptosis in the kidney tissue of Se-deficient broilers. This finding may provide new research ideas for kidney injury and cell death due to Se deficiency.

Endoplasmic Reticulum Stress of Gut Enterocyte and Intestinal Diseases

The endoplasmic reticulum, a vast reticular membranous network from the nuclear envelope to the plasma membrane responsible for the synthesis, maturation, and trafficking of a wide range of proteins, is considerably sensitive to changes in its luminal homeostasis. The loss of ER luminal homeostasis leads to abnormalities referred to as endoplasmic reticulum (ER) stress. Thus, the cell activates an adaptive response known as the unfolded protein response (UPR), a mechanism to stabilize ER homeostasis under severe environmental conditions. ER stress has recently been postulated as a disease research breakthrough due to its significant role in multiple vital cellular functions. This has caused numerous reports that ER stress-induced cell dysfunction has been implicated as an essential contributor to the occurrence and development of many diseases, resulting in them targeting the relief of ER stress. This review aims to outline the multiple molecular mechanisms of ER stress that can elucidate ER as an expansive, membrane-enclosed organelle playing a crucial role in numerous cellular functions with evident changes of several cells encountering ER stress. Alongside, we mainly focused on the therapeutic potential of ER stress inhibition in gastrointestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer. To conclude, we reviewed advanced research and highlighted future treatment strategies of ER stress-associated conditions.

Intermedin1-53 Inhibits NLRP3 Inflammasome Activation by Targeting IRE1α in Cardiac Fibrosis

Intermedin (IMD), a paracrine/autocrine peptide, protects against cardiac fibrosis. However, the underlying mechanism remains poorly understood. Previous study reports that activation of nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome contributes to cardiac fibrosis. In this study, we aimed to investigate whether IMD mitigated cardiac fibrosis by inhibiting NLRP3. Cardiac fibrosis was induced by angiotensin II (Ang II) infusion for 2 weeks in rats. Western blot, real-time PCR, histological staining, immunofluorescence assay, RNA sequencing, echocardiography, and hemodynamics were used to detect the role and the mechanism of IMD in cardiac fibrosis. Ang II infusion resulted in rat cardiac fibrosis, shown as over-deposition of myocardial interstitial collagen and cardiac dysfunction. Importantly, NLRP3 activation and endoplasmic reticulum stress (ERS) were found in Ang II-treated rat myocardium. Ang II infusion decreased the expression of IMD and increased the expression of the receptor system of IMD in the fibrotic rat myocardium. IMD treatment attenuated the cardiac fibrosis and improved cardiac function. In addition, IMD inhibited the upregulation of NLRP3 markers and ERS markers induced by Ang II. In vitro, IMD knockdown by small interfering RNA significantly promoted the Ang II-induced cardiac fibroblast and NLRP3 activation. Moreover, silencing of inositol requiring enzyme 1 α (IRE1α) blocked the effects of IMD inhibiting fibroblast and NLRP3 activation. Pre-incubation with PKA pathway inhibitor H89 blocked the effects of IMD on the anti-ERS, anti-NLRP3, and anti-fibrotic response. In conclusion, IMD alleviated cardiac fibrosis by inhibiting NLRP3 inflammasome activation through suppressing IRE1α via the cAMP/PKA pathway.

Cadmium and molybdenum co-induce pyroptosis and apoptosis by PTEN/PI3K/AKT axis in the liver of ducks

Cadmium (Cd) and excessive molybdenum (Mo) have adverse impacts on animals. However, the hepatotoxicity co-induced by Cd and Mo in ducks has not been fully elucidated. In order to explore...

Potential therapeutic role of pyroptosis mediated by the NLRP3 inflammasome in type 2 diabetes and its complications

As a new way of programmed cell death, pyroptosis plays a vital role in many diseases. In recent years, the relationship between pyroptosis and type 2 diabetes (T2D) has received increasing attention. Although the current treatment options for T2D are abundant, the occurrence and development of T2D appear to continue, and the poor prognosis and high mortality of patients with T2D remain a considerable burden in the global health system. Numerous studies have shown that pyroptosis mediated by the NLRP3 inflammasome can affect the progression of T2D and its complications; targeting the NLRP3 inflammasome has potential therapeutic effects. In this review, we described the molecular mechanism of pyroptosis more comprehensively, discussed the most updated progress of pyroptosis mediated by NLRP3 inflammasome in T2D and its complications, and listed some drugs and agents with potential anti-pyroptosis effects. Based on the available evidence, exploring more mechanisms of the NLRP3 inflammasome pathway may bring more options and benefits for preventing and treating T2D and drug development.

GSDMD-mediated pyroptosis: a critical mechanism of diabetic nephropathy

Pyroptosis is a recently identified mechanism of programmed cell death related to Caspase-1 that triggers a series of inflammatory reactions by releasing several proinflammatory factors such as IL-1β and IL-18. The process is characterised by the rupture of cell membranes and the release of cell contents through the mediation of gasdermin (GSDM) proteins. GSDMD is an important member of the GSDM family and plays a critical role in the two pathways of pyroptosis. Diabetic nephropathy (DN) is a microvascular complication of diabetes and a major cause of end-stage renal disease. Recently, it was revealed that GSDMD-mediated pyroptosis plays an important role in the occurrence and development of DN. In this review, we focus on two types of kidney cells, tubular epithelial cells and renal podocytes, to illustrate the mechanism of pyroptosis in DN and provide new ideas for the prevention, early diagnosis and molecular therapy of DN.

Inhibition of the PERK/TXNIP/NLRP3 Axis by Baicalin Reduces NLRP3 Inflammasome-Mediated Pyroptosis in Macrophages Infected with Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) remains a significant threat to global health as it induces granuloma and systemic inflammatory responses during active tuberculosis. Mtb can induce macrophage pyroptosis, leading to the release of IL-1β and tissue damage, promoting its spread. Here, we established an in vitro Mtb-infected macrophage model to seek an effective antipyroptosis agent. Baicalin, isolated from Radix Scutellariae, was found to reduce pyroptosis in Mtb-infected macrophages. Baicalin could inhibit activation of the PERK/eIF2α pathway and thus downregulates TXNIP expression and subsequently reduces activation of the NLRP3 inflammasome, resulting in reduced pyroptosis in Mtb-infected macrophages. In conclusion, baicalin reduced pyroptosis by inhibiting the PERK/TXNIP/NLRP3 axis and might thus be a new adjuvant host-directed therapy (HDT) drug.

Baicalein alleviates pyroptosis and inflammation in hyperlipidemic pancreatitis by inhibiting NLRP3/Caspase-1 pathway through the miR-192-5p/TXNIP axis

OBJECTIVE

Hyperlipidemia is a main reason of pancreatitis. Baicalein can ameliorate the pathological manifestations of pancreatitis. This study evaluated underlying molecular mechanism of baicalein in hyperlipidemic pancreatitis (HP).

METHODS

HP rat model was successfully established and treated with baicalein. Amylase (AMY) activity and concentrations of triglyceride (TG) and total cholesterol (TC) were detected. Levels of pyroptosis-related proteins (GSDMD, IL-1β, IL-18) were detected by Western blot. Expressions of inflammatory factors (IL-6, TNF-α, IL-4) were detected by ELISA. Toxicity of baicalein on pancreatic acinar cells (PACs) was detected by MTT assay. HP cell model was established by 0.1 mM palmitic acid and CCK-8 stimulation. Target relation of miR-192-5p and TXNIP was predicted and verified by RNA22 v2 database and dual-luciferase reporter assay. Expressions of miR-192-5p and TXNIP were detected by RT-qPCR. Pyroptosis and inflammation in PACs were detected after baicalein treatment combined with silencing miR-192-5p or TXNIP overexpression. Protein levels of NLRP3/Caspase-1 pathway in vivo and vitro were detected.

RESULTS

Baicalein reduced concentrations of TG and TC, AMY activity, and pathological scores in HP rat model, reduced LDH activity, pyroptosis and alleviated inflammation in vivo and in vitro. Mechanically, miR-192-5p targeted TXNIP, and baicalein inhibited pyroptosis and inflammation by up-regulating miR-192-5p and down-regulating TXNIP. Silencing miR-192-5p or TXNIP overexpression partially abolished the anti-pyroptosis and anti-inflammatory effect of baicalein on PACs. Baicalein attenuated HP by inhibiting the NLRP3/Caspase-1 pathway.

CONCLUSION

Baicalein alleviated pyroptosis and inflammation in HP by inhibiting the NLRP3/Caspase-1 pathway through miR-192-5p upregulation and TXNIP inhibition.

Role of Thioredoxin-Interacting Protein in Diabetic Fatty Kidney Induced by Advanced Glycation End-Products

Advanced glycation end-products (AGEs) have been identified as the etiological factors associated with the fatty kidney. Thioredoxin-interacting protein (TXNIP) might be a mediator involved in AGE-induced fatty kidney. This study focused on investigating how TXNIP affected the AGE-mediated renal lipid deposition. In an in vivo experiment, the db/db mice injected with the lentiviral vector encoding shRNA targeting TXNIP were given the AIN-76 basal or the high-AGE diet. TXNIP-targeting siRNA-transfected human renal proximal tubular epithelial (HK-2) cells were exposed to AGE-BSA in a study in vitro. The results showed that the silencing of TXNIP reduced tubular lipid droplets and intracellular cholesterol content, as well as upregulated Insig-1 and downregulated HMGCoAR, LDLr, nSREBP-2, and SCAP in the kidneys of the db/db mice, the high-AGE-diet-fed db/db mice, and AGE-BSA-treated HK-2 cells. Furthermore, AGE-BSA enhanced SCAP-SREBP-2 complex formation while promoting their transportation to the Golgi apparatus. However, these could be inhibited by TXNIP silencing in the HK-2 cells. The above findings indicated that TXNIP knockdown mitigated the accumulation of renal tubular lipids in diabetes through the regulation of SCAP, thereby inhibiting the SCAP-SREBP-2 signaling pathway, resulting in reduced cholesterol uptake and synthesis. Therefore, TXNIP might be a potential therapeutic target to treat a diabetic fatty kidney.

Pyroptosis in Kidney Disease

In the last several decades, apoptosis interference has been considered clinically irrelevant in the context of renal injury. Recent discovery of programmed necrotic cell death, including necroptosis, ferroptosis, and pyroptosis refreshed our understanding of the role of cell death in kidney disease. Pyroptosis is characterized by a lytic pro- inflammatory type of cell death resulting from gasdermin-induced membrane permeabilization via activation of inflammatory caspases and inflammasomes. The danger-associated molecular patterns (DAMPs), alarmins and pro-inflammatory cytokines are released from pyroptotic cells in an uncontrolled manner, which provoke inflammation, resulting in secondary organ or tissue injuries. The caspases and inflammasome activation-related proteins and pore-forming effector proteins known as GSDMD and GSDME have been implicated in a variety of acute and chronic microbial and non-microbial kidney diseases. Here, we review the recent advances in pathological mechanisms of pyroptosis in kidney disease and highlight the potential therapeutic strategies in future.

Pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN), a sterile inflammatory disease, is a serious complication of diabetes mellitus. However, recent evidence indicates that pyroptosis, a new term for pro-inflammatory cell death featured by gasdermin D (GSDMD)-stimulated plasma membrane pore generation, cell expansion and rapid lysis with the extensive secretion of pro-inflammatory factors, including interleukin-1β (IL-1β) and -18 (IL-18) may be involved in DN. Caspase-1-induced canonical and caspase-4/5/11-induced non-canonical inflammasome-signaling pathways are mainly believed to participate in pyroptosis-mediated cell death. Further research has uncovered that activation of the caspase-3/8 signaling pathway may also activate pyroptosis. Accumulating evidence has shown that NLRP3 inflammasome activation plays a critical role in promoting the pathogenesis of DN. In addition, current studies have suggested that pyroptosis-induced cell death promotes several diabetic complications that include DN. Our present study briefs the cellular mechanisms of pyroptosis-related signaling pathways and their impact on the promotion of DN. In this review, several investigational compounds suppressing pyroptosis-mediated cell death are explored as promising therapeutics in DN.

miR-200a-3p Attenuates Coronary Microembolization-Induced Myocardial Injury in Rats by Inhibiting TXNIP/NLRP3-Mediated Cardiomyocyte Pyroptosis

Coronary microembolization (CME) commonly develops as a complication after percutaneous coronary intervention (PCI), and associated inflammation is a leading driver of myocardial damage. Cardiomyocyte loss in the context of ischemic myocardial disease has been linked to inflammatory pyroptotic cell death. Additionally, miR-200a-3p dysregulation has been linked to myocardial ischemia-reperfusion and many other pathological conditions. However, how miR-200a-3p impacts cardiomyocyte pyroptosis in the context of CME remains to be assessed. Herein, a rat model of CME was established via the injection of microembolic spheres into the left ventricle. When myocardial tissue samples from these rats were analyzed, miR-200a-3p levels were markedly decreased, whereas thioredoxin-interacting protein (TXNIP) levels were increased. The ability of miR-200a-3p to directly target TXNIP and to control its expression was confirmed via dual-luciferase reporter assay. Adeno-associated virus serotype 9-pre-miR-200a-3p (AAV-miR-200a-3p) construct transfection was then employed as a means of upregulating this miRNA in CME model rats. Subsequent assays, including echocardiography, enzyme-linked immunosorbent assays (ELISAs), hematoxylin-eosin (H&E) staining, hematoxylin-basic fuchsin-picric acid (HBFP) staining, TdT-mediated dUTP nick-end labeling (TUNEL) staining, immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting revealed that miR-200a-3p overexpression inhibited cardiomyocyte pyroptosis and alleviated CME-induced myocardial injury by inhibiting the TXNIP/NOD-like receptor family pyrin domain-containing 3 (NLRP3) pathway. The ability of miR-200a-3p to protect against CME-induced myocardial injury thus highlights a novel approach to preventing or treating such myocardial damage in clinical settings.

Circular Ribonucleic Acid circFTO Promotes Angiogenesis and Impairs Blood-Retinal Barrier Via Targeting the miR-128-3p/Thioredoxin Interacting Protein Axis in Diabetic Retinopathy

Background: Increasing attention has been attracted by the role of circular RNAs (circRNAs) in ocular diseases. Previous study has revealed that circ_0005941 (also known as circFTO, an alpha-ketoglutarate-dependent dioxygenase) was upregulated in the vitreous humor of diabetic retinopathy (DR), while its underlying mechanism in DR remains unknown. Methods: Retinal vascular endothelial cells (RVECs) treated with high glucose (HG) were used to establish the DR cell model. The in vivo assays were conducted using streptozotocin-induced diabetic mice. The circular structure and stability of circFTO were identified by Sanger sequencing and RNase R treatment. RT-qPCR analysis was used to detect the RNA expression. The levels of the mRNA-encoded protein thioredoxin-interacting protein (TXNIP) or angiogenesis-associated proteins (VEGFA, PDGF, and ANG2) and blood-retinal barrier (BRB)-related proteins (ZO-1, Occludin, and Claudin-5) were measured by Western blot. The viability of RVECs was measured using CCK-8 assays. The angiogenesis of RVECs was assessed using tube formation assays in vitro. Endothelial permeability assays were conducted to examine the function of the BRB. The binding between genes was explored using RNA pulldown and luciferase reporter assays. Results: CircFTO was upregulated in HG-treated RVECs. CircFTO deficiency reversed the HG-induced increase in the viability and angiogenesis of RVECs and alleviated HG-mediated impairment of the BRB. MiR-128-3p bound with circFTO and was downregulated in HG-treated RVECs. TXNIP was a downstream target gene of miR-128-3p. TXNIP was highly expressed in the DR cell model. Rescue assays revealed that circFTO promoted angiogenesis and impaired the blood-retinal barrier by upregulating TXNIP. In the DR mouse model, circFTO silencing inhibited angiogenesis and promoted BRB recovery in vivo. Conclusion: CircFTO promotes angiogenesis and impairs the blood-retinal barrier in vitro and in vivo by binding with miR-128-3p to upregulate TXNIP in DR.

ROCK1 regulates sepsis-induced acute kidney injury via TLR2-mediated endoplasmic reticulum stress/pyroptosis axis

BACKGROUND

It has been reported that ROCK1 participates in the progression of multiple diseases, including septic intestinal barrier, cardiac dysfunction and acute lung injury. However, its regulatory role and specific mechanism in sepsis-induced acute kidney injury (AKI) remain unclear.

METHODS

Cecal ligation puncture (CLP) was conducted to establish sepsis mouse model, and in vitro model was achieved by lipopolysaccharide (LPS) stimulation. Genes expression was evaluated by qRT-PCR, western blot or ELISA was conducted to assess the levels of proteins. Hoechst staining was performed to evaluate cell pyroptosis. LDH activity assay was detected to assess cytotoxicity. Immunohistochemistry was conducted to detect Ly-6G expression and neutrophils distribution in kidney tissues of mice. H&E and TUNEL staining were carried to evaluate kidney injury of mice.

RESULTS

Our findings illuminated that ROCK1 was highly expressed in sepsis-induced AKI, and ROCK1 knockdown inhibited NLRP3-mediated cell pyroptosis in LPS-induced HK-2 cells. Moreover, ROCK1 modulated HK-2 cell pyroptosis by regulating endoplasmic reticulum stress (ERS). TLR2 inhibitor could suppress ERS mediated cell pyroptosis under LPS treatment. Further, TLR2 activator partially reversed the effects of ROCK1 inhibition on ERS mediated pyroptosis in LPS-treated HK-2 cells and CLP mice.

CONCLUSION

In conclusion, ROCK1 may regulate sepsis-induced AKI via TLR2-mediated ERS/pyroptosis axis. Our data demonstrated the role and underlying mechanism of ROCK1 in septic AKI, providing theoretical basis for sepsis-induced AKI treatment.

NLRP3 Inflammasome in Metabolic-Associated Kidney Diseases: An Update

Metabolic syndrome (MS) is a group of complex metabolic disorders syndrome, which refers to the pathological state of metabolism disorder of protein, fat, carbohydrate and other substances in human body. The kidney is an important organ of metabolism, and various metabolic disorders can lead to the abnormalities in the structure and function of the kidney. The recognition of pathogenesis and treatment measures of renal damage in MS is a very important part for the renal function preserve. Inflammatory response caused by various metabolic factors is a protective mechanism of the body, but persistent inflammation will become a harmful factor and aggravate kidney damage. Inflammasomes are sensors of the innate immune system that play crucial roles in initiating inflammation in response to acute infections and chronic diseases. They are multiprotein complex composed of cytoplasmic sensors (mainly NLR family members), apoptosis-associated speck-like protein (ASC or PYCARD) and pro-caspase-1. After receiving exogenous and endogenous stimuli, the sensors begin to assemble inflammasome and then promote the release of inflammatory cytokines IL-1β and IL-18, resulting in a special way of cell death named pyroptosis. In the kidney, NLRP3 inflammasome can be activated by a variety of pathways, which eventually leads to inflammatory infiltration, renal intrinsic cell damage and renal function decline. This paper reviews the function and specific regulatory mechanism of inflammasome in kidney damage caused by various metabolic disorders, which will provide a new therapeutic perspective and targets for kidney diseases.

Role of Pyroptosis in Diabetes and Its Therapeutic Implications

Pyroptosis is mainly considered as a new pro-inflammatory mediated-programmed cell death. In addition, pyroptosis is described by gasdermin-induced pore formation on the membrane, cell swelling and rapid lysis, and several pro-inflammatory mediators interleukin-1β (IL-1β) and interleukin-18 (IL-18) release. Extensive studies have shown that pyroptosis is commonly involved by activating the caspase-1-dependent canonical pathway and caspase-4/5/11-dependent non-canonical pathway. However, pyroptosis facilitates local inflammation and inflammatory responses. Current researches have reported that pyroptosis promotes the progression of several diabetic complications. Emerging studies have suggested that some potential molecules targeting the pyroptosis and inflammasome signaling pathways could be a novel therapeutic avenue for managing and treating diabetes and its complications in the near future. Our narrative review concisely describes the possible mechanism of pyroptosis and its progressive understanding of the development of diabetic complications.

The Role of the Effects of Endoplasmic Reticulum Stress on NLRP3 Inflammasome in Diabetes

Endoplasmic reticulum (ER) is an important organelle for the protein synthesis, modification, folding, assembly, and the transport of new peptide chains. When the folding ability of ER proteins is impaired, the accumulation of unfolded or misfolded proteins in ER leads to endoplasmic reticulum stress (ERS). The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome, can induce the maturation and secretion of interleukin-1beta (IL-1β) and IL-18 through activating caspase-1. It is associated with many diseases. Studies have shown that ERS can regulate NLRP3 inflammasome in many diseases including diabetes. However, the mechanism of the effects of ERS on NLRP3 inflammasome in diabetes has not been fully understood. This review summarizes the recent researches about the effects of ERS on NLRP3 inflammasome and the related mechanism in diabetes to provide ideas for the relevant basic research in the future.

Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook

Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.