The role of inflammasomes in kidney disease

Renal IL-23-Dependent Type 3 Innate Lymphoid Cells Link Crystal-induced Intrarenal Inflammasome Activation with Kidney Fibrosis

Chronic inflammasome activation in mononuclear phagocytes (MNPs) promotes fibrosis in various tissues, including the kidney. The cellular and molecular links between the inflammasome and fibrosis are unclear. To address this question, we fed mice lacking various immunological mediators an adenine-enriched diet, which causes crystal precipitation in renal tubules, crystal-induced inflammasome activation, and renal fibrosis. We found that kidney fibrosis depended on an intrarenal inflammasome-dependent type 3 immune response driven by its signature transcription factor Rorc (retinoic acid receptor-related orphan receptor C gene), which was partially carried out by type 3 innate lymphoid cells (ILC3s). The role of ILCs in the kidney is less well known than in other organs, especially that of ILC3. In this article, we describe that depletion of ILCs or genetic deficiency for Rorc attenuated kidney inflammation and fibrosis. Among the inflammasome-derived cytokines, only IL-1β expanded ILC3 and promoted fibrosis, whereas IL-18 caused differentiation of NKp46+ ILC3. Deficiency of the type 3 maintenance cytokine, IL-23, was more protective than IL-1β inhibition, which may be explained by the downregulation of the IL-1R, but not of the IL-23R, by ILC3 early in the disease, allowing persistent sensing of IL-23. Mechanistically, ILC3s colocalized with renal MNPs in vivo as shown by multiepitope-ligand cartography. Cell culture experiments indicated that renal ILC3s caused renal MNPs to increase TGF-β production that stimulated fibroblasts to produce collagen. We conclude that ILC3s link inflammasome activation with kidney inflammation and fibrosis and are regulated by IL-1β and IL-23.

Pathological mechanisms of kidney disease in ageing

The kidney is a metabolically active organ that requires energy to drive processes such as tubular reabsorption and secretion, and shows a decline in function with advancing age. Various molecular mechanisms, including genomic instability, telomere attrition, inflammation, autophagy, mitochondrial function, and changes to the sirtuin and Klotho signalling pathways, are recognized regulators of individual lifespan and pivotal factors that govern kidney ageing. Thus, mechanisms that contribute to ageing not only dictate renal outcomes but also exert a substantial influence over life expectancy. Conversely, kidney dysfunction, in the context of chronic kidney disease (CKD), precipitates an expedited ageing trajectory in individuals, leading to premature ageing and a disconnect between biological and chronological age. As CKD advances, age-related manifestations such as frailty become increasingly conspicuous. Hence, the pursuit of healthy ageing necessitates not only the management of age-related complications but also a comprehensive understanding of the processes and markers that underlie systemic ageing. Here, we examine the hallmarks of ageing, focusing on the mechanisms by which they affect kidney health and contribute to premature organ ageing. We also review diagnostic methodologies and interventions for premature ageing, with special consideration given to the potential of emerging therapeutic avenues to target age-related kidney diseases.

Natural polysaccharides as promising reno-protective agents for the treatment of various kidney injury

Renal injury, a prevalent clinical outcome with multifactorial etiology, imposes a substantial burden on society. Currently, there remains a lack of effective management and treatments. Extensive research has emphasized the diverse biological effects of natural polysaccharides, which exhibit promising potential for mitigating renal damage. This review commences with the pathogenesis of four common renal diseases and the shared mechanisms underlying renal injury. The renoprotective roles of polysaccharides in vivo and in vitro are summarized in the following five aspects: anti-oxidative stress effects, anti-apoptotic effects, anti-inflammatory effects, anti-fibrotic effects, and gut modulatory effects. Furthermore, we explore the structure-activity relationship and bioavailability of polysaccharides in relation to renal injury, as well as investigate their utility as biomaterials for alleviating renal injury. The clinical experiments of polysaccharides applied to patients with chronic kidney disease are also reviewed. Broadly, this review provides a comprehensive perspective on the research direction of natural polysaccharides in the context of renal injury, with the primary aim to serve as a reference for the clinical development of polysaccharides as pharmaceuticals and prebiotics for the treatment of kidney diseases.

Significance of serum NLRP3 as a potential predictor of 5-year death in hemodialysis patients: A prospective observational cohort study

Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) is involved in inflammatory response. This study was done to explore the role of serum NLRP3 as a predictive biomarker of death after hemodialysis. In this prospective observational study of 331 patients undergoing maintenance hemodialysis, serum NLRP3 levels were measured. Univariate analysis and multivariate analysis were sequentially performed to determine predictors of 5-year death after hemodialysis. Age, major adverse cardiac and cerebral events (MACCE), and serum NLRP3 levels independently predicted 5-year mortality and overall survival (all P < .05). No interactions were found between serum NLRP3 levels and other variables, such as age, gender, hypertension, diabetes mellitus, primary renal diseases, and MACCE (all P interaction > .05). Serum NLRP3 levels were linearly correlated with risk of death and overall survival under restricted cubic spline (both P > .05) and substantially discriminated patients at risk of death under receiver operating characteristic curve (P < .001). Two models, in which age, MACCE, and serum NLRP3 were combined, were built to predict 5-year mortality and overall survival. The mortality prediction model had significantly higher predictive ability than age, AMCCE, and serum NLRP3 alone under receiver operating characteristic curve (all P < .05). The models, which were graphically represented by nomograms, performed well under calibration curve and decision curve. Serum NLRP3 levels are independently related to 5-year mortality and overall survival of patients after hemodialysis, suggesting that serum NLRP3 may be a potential prognostic biomarker of hemodialysis patients.

Long Non-coding RNA NEAT1 , NOD-Like Receptor Family Protein 3 Inflammasome, and Acute Kidney Injury

Key Points

Background

AKI is common in hospitalized patients and is associated with high mortality. Inflammation plays a key role in the pathophysiology of AKI. Long non-coding RNAs (lncRNAs) are increasingly recognized as regulators of the inflammatory and immune response, but its role in AKI remains unclear.

Methods

We explored the role of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) in (1) a cross-sectional and longitudinal cohort of AKI in humans, (2) three murine models of septic and aseptic AKI, and (3) cultured C1.1 mouse kidney tubular cells.

Results

In humans, hospitalized patients with AKI (N=66) demonstrated significantly higher lncRNA NEAT1 levels in urinary sediment cells and buffy coat versus control participants (N=152) from a primary care clinic; among six kidney transplant recipients, NEAT1 levels were the highest immediately after transplant surgery, followed by a prompt decline to normal levels in parallel with recovery of kidney function. In mice with AKI induced by sepsis (by LPS injection or cecal ligation and puncture) and renal ischemia-reperfusion, kidney tubular Neat1 was increased versus sham-operated mice. Knockdown of Neat1 in the kidney using short hairpin RNA preserved kidney function and suppressed overexpression of the AKI biomarker neutrophil gelatinase-associated lipocalin, leukocyte infiltration, and both intrarenal and systemic inflammatory cytokines IL-6, CCL-2, and IL-1β. In LPS-treated C1.1 cells, Neat1 was overexpressed by TLR4/NF-κB signaling and translocated from the cell nucleus into the cytoplasm where it promoted activation of nucleotide oligomerization domain-like receptor family protein 3 inflammasomes by binding with the scaffold protein receptor of activated protein C kinase 1. Silencing Neat1 ameliorated LPS-induced cell inflammation, whereas its overexpression upregulated IL-6 and CCL-2 expression even without LPS stimulation.

Conclusions

Our findings demonstrate a pathogenic role of NEAT1 induction in human and mice during AKI with alleviation of kidney injury in three experimental models of septic and aseptic AKI after knockdown of Neat1. LPS/TLR4-induced Neat1 overexpression in tubular epithelial cells increased the inflammatory response by binding with the scaffold protein, receptor of activated protein C kinase 1, to activate nucleotide oligomerization domain-like receptor family protein 3 inflammasomes.

Targeting novel regulated cell death: Ferroptosis, pyroptosis and necroptosis in anti-PD-1/PD-L1 cancer immunotherapy

Chemotherapy, radiotherapy, and immunotherapy represent key tumour treatment strategies. Notably, immune checkpoint inhibitors (ICIs), particularly anti-programmed cell death 1 (PD1) and anti-programmed cell death ligand 1 (PD-L1), have shown clinical efficacy in clinical tumour immunotherapy. However, the limited effectiveness of ICIs is evident due to many cancers exhibiting poor responses to this treatment. An emerging avenue involves triggering non-apoptotic regulated cell death (RCD), a significant mechanism driving cancer cell death in diverse cancer treatments. Recent research demonstrates that combining RCD inducers with ICIs significantly enhances their antitumor efficacy across various cancer types. The use of anti-PD-1/PD-L1 immunotherapy activates CD8+ T cells, prompting the initiation of novel RCD forms, such as ferroptosis, pyroptosis, and necroptosis. However, the functions and mechanisms of non-apoptotic RCD in anti-PD1/PD-L1 therapy remain insufficiently explored. This review summarises the emerging roles of ferroptosis, pyroptosis, and necroptosis in anti-PD1/PD-L1 immunotherapy. It emphasises the synergy between nanomaterials and PD-1/PD-L1 inhibitors to induce non-apoptotic RCD in different cancer types. Furthermore, targeting cell death signalling pathways in combination with anti-PD1/PD-L1 therapies holds promise as a prospective immunotherapy strategy for tumour treatment.

Podocyte programmed cell death in diabetic kidney disease: Molecular mechanisms and therapeutic prospects

Diabetic kidney disease (DKD) is the primary cause of chronic kidney and end-stage renal disease. Glomerular podocyte loss and death are pathological hallmarks of DKD, and programmed cell death (PCD) in podocytes is crucial in DKD progression. PCD involves apoptosis, autophagy, ferroptosis, pyroptosis, and necroptosis. During DKD, PCD in podocytes is severely impacted and primarily characterized by accelerated podocyte apoptosis and suppressed autophagy. These changes lead to a gradual decrease in podocyte numbers, impairing the glomerular filtration barrier function and accelerating DKD progression. However, research on the interactions between the different types of PCD in podocytes is lacking. This review focuses on the novel roles and mechanisms of PCD in the podocytes of patients with DKD. Additionally, we summarize clinical drugs capable of regulating podocyte PCD, present challenges and prospects faced in developing drugs related to podocyte PCD and suggest that future research should further explore the detailed mechanisms of podocyte PCD and interactions among different types of PCD.

Engineering Photothermal Catalytic CO2 Nanoreactor for Osteomyelitis Treatment by In Situ CO Generation

Photocatalytic carbon dioxide (CO2) reduction is an effective method for in vivo carbon monoxide (CO) generation for antibacterial use. However, the available strategies mainly focus on utilizing visible-light-responsive photocatalysts to achieve CO generation. The limited penetration capability of visible light hinders CO generation in deep-seated tissues. Herein, a photothermal CO2 catalyst (abbreviated as NNBCs) to achieve an efficient hyperthermic effect and in situ CO generation is rationally developed, to simultaneously suppress bacterial proliferation and relieve inflammatory responses. The NNBCs are modified with a special polyethylene glycol and further embellished by bicarbonate (BC) decoration via ferric ion-mediated coordination. Upon exposure to 1064 nm laser irradiation, the NNBCs facilitated efficient photothermal conversion and in situ CO generation through photothermal CO2 catalysis. Specifically, the photothermal effect accelerated the decomposition of BC to produce CO2 for photothermal catalytic CO production. Benefiting from the hyperthermic effect and in situ CO production, in vivo assessments using an osteomyelitis model confirmed that NNBCs can simultaneously inhibit bacterial proliferation and attenuate the photothermal effect-associated pro-inflammatory response. This study represents the first attempt to develop high-performance photothermal CO2 nanocatalysts to achieve in situ CO generation for the concurrent inhibition of bacterial growth and attenuation of inflammatory responses.

VX-702 Ameliorates the Severity of Sepsis-Associated Acute Kidney Injury by Downregulating Inflammatory Factors in Macrophages

Purpose

Sepsis-associated acute kidney injury (S-AKI) contributes to high mortality, but it is lack of specific treatments. We aimed to investigate the underlying mechanism of S-AKI and to identify target drugs to alleviate AKI.

Methods

We establish a stable mouse model of S-AKI by Pseudomonas aeruginosa incision infection. Based on high-throughput sequencing and bioinformatics analysis, we investigated the underlying mechanism and selected the target drug (VX-702) for S-AKI. An in vitro model established by co-cultured of kidney tubular epithelial cell line (TCMK-1) cells with lipopolysaccharide (LPS)-induced leukemic monocyte/macrophage cells (RAW264.7), we explored the effect of VX-702 on S-AKI.

Results

The data showed interleukin (IL)-6 and IL-1β were the hub genes, and the mitogen-activated protein kinase (MAPK) signaling pathway was the main pathway involved in S-AKI. Administration of VX-702 by oral gavage decreased the elevated concentrations of IL-6, IL-1β, serum creatinine, and blood urea nitrogen in mice with S-AKI. Moreover, VX-702 reduced the number of apoptotic cells in damaged kidney tissues. Cell viability was decreased, and the number of apoptotic cells was increased in TCMK-1 cells co-cultured with LPS-induced RAW264.7 cells compared to LPS-induced TCMK-1 cells. VX-702 treatment reversed this effect. VX-702 treatment reduced the levels of phosphorylated p38 MAPK and proinflammatory cytokines in RAW264.7 cells and the supernatant. VX-702 could bind IL-6, IL-1β and MAPK, and affect the binding of IL-1β and its receptor, as demonstrated by molecular docking.

Conclusion

VX-702 ameliorated S-AKI by inhibiting the release of proinflammatory cytokines from macrophages, indicating its potential as a novel therapeutic for S-AKI treatment.

Dapagliflozin Reduces Urinary Kidney Injury Biomarkers in Chronic Kidney Disease Irrespective of Albuminuria Level

The beneficial effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with chronic kidney disease (CKD) with low albuminuria levels have not been established. This study aimed to compare the effects of dapagliflozin on kidney injury biomarkers in patients with CKD stratified by albuminuria level. We prospectively enrolled healthy volunteers (HVs; n = 20) and patients with CKD (n = 54) with and without diabetes mellitus. Patients with CKD were divided into two age-matched and sex-matched subgroups according to urinary albumin-creatinine ratio (uACR) levels (<300 mg/g and ≥300 mg/g). The CKD group received dapagliflozin (10 mg/day). Urine samples were collected before treatment and after 3 and 6 months of dapagliflozin. Urinary kidney injury molecule-1 (KIM-1), interleukin-1β (IL-1β), and mitochondrial DNA nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND1) copy number were measured. The estimated glomerular filtration rate (eGFR) of patients with CKD was lower than that of HVs (P < 0.001). During the study period, eGFR decreased and uACR did not change in the CKD group. Kidney injury markers were significantly elevated in patients with CKD compared with those in HVs. Dapagliflozin reduced urinary KIM-1, IL-1β, and mtDNA copy number in patients with CKD after 6 months of treatment. In further, the levels of urinary KIM-1 and IL-1β, patients with CKD decreased after 6 months of dapagliflozin treatment regardless of albuminuria level. Dapagliflozin reduced urinary kidney injury biomarkers in patients with CKD, regardless of albuminuria level. These findings suggest that SGLT2 inhibitors may also attenuate the progression of low albuminuric CKD.

Unlocking renal Restoration: Mesaconine from Aconitum plants restore mitochondrial function to halt cell apoptosis in acute kidney injury

Acute kidney injury (AKI) is characterized by a sudden decline in renal function. Traditional Chinese medicine has employed Fuzi for kidney diseases; however, concerns about neurotoxicity and cardiotoxicity have constrained its clinical use. This study explored mesaconine, derived from processed Fuzi, as a promising low-toxicity alternative for AKI treatment. In this study, we assessed the protective effects of mesaconine in gentamicin (GM)-induced NRK-52E cells and AKI rat models in vitro and in vivo, respectively. Mesaconine promotes the proliferation of damaged NRK-52E cells and down-regulates intracellular transforming growth factor β1 (TGF-β1) and kidney injury molecule 1 (KIM-1) to promote renal cell repair. Concurrently, mesaconine restored mitochondrial morphology and permeability transition pores, reversed the decrease in mitochondrial membrane potential, mitigated mitochondrial dysfunction, decreased ATP production, inhibited inflammatory factor release, and reduced early apoptosis rates. In vivo, GM-induced AKI rat models exhibited elevated AKI biomarkers, in which mesaconine was effectively reduced, indicating improved renal function. Mesaconine enhanced superoxide dismutase activity, reduced malondialdehyde content, alleviated inflammatory infiltrate, mitigated tubular and glomerular lesions, and downregulated NF-κB (nuclear factor-κb) p65 expression, leading to decreased tumor necrosis factor-α (TNF-α) and IL-1β (interleukin-1β) levels in GM-induced AKI animals. Furthermore, mesaconine inhibited the expression of renal pro-apoptotic proteins (Bax, cytochrome c, cleaved-caspase 9, and cleaved-caspase 3) and induced the release of the anti-apoptotic protein bcl-2, further suppressing apoptosis. This study highlighted the therapeutic potential of mesaconine in GM-induced AKI. Its multifaceted mechanisms, including the restoration of mitochondrial dysfunction, anti-inflammatory and antioxidant effects, and apoptosis mitigation, make mesaconine a promising candidate for further exploration in AKI management.

Renal macrophages and NLRP3 inflammasomes in kidney diseases and therapeutics

Macrophages are exceptionally diversified cell types and perform unique features and functions when exposed to different stimuli within the specific microenvironment of various kidney diseases. In instances of kidney tissue necrosis or infection, specific patterns associated with damage or pathogens prompt the development of pro-inflammatory macrophages (M1). These M1 macrophages contribute to exacerbating tissue damage, inflammation, and eventual fibrosis. Conversely, anti-inflammatory macrophages (M2) arise in the same circumstances, contributing to kidney repair and regeneration processes. Impaired tissue repair causes fibrosis, and hence macrophages play a protective and pathogenic role. In response to harmful stimuli within the body, inflammasomes, complex assemblies of multiple proteins, assume a pivotal function in innate immunity. The initiation of inflammasomes triggers the activation of caspase 1, which in turn facilitates the maturation of cytokines, inflammation, and cell death. Macrophages in the kidneys possess the complete elements of the NLRP3 inflammasome, including NLRP3, ASC, and pro-caspase-1. When the NLRP3 inflammasomes are activated, it triggers the activation of caspase-1, resulting in the release of mature proinflammatory cytokines (IL)-1β and IL-18 and cleavage of Gasdermin D (GSDMD). This activation process therefore then induces pyroptosis, leading to renal inflammation, cell death, and renal dysfunction. The NLRP3-ASC-caspase-1-IL-1β-IL-18 pathway has been identified as a factor in the development of the pathophysiology of numerous kidney diseases. In this review, we explore current progress in understanding macrophage behavior concerning inflammation, injury, and fibrosis in kidneys. Emphasizing the pivotal role of activated macrophages in both the advancement and recovery phases of renal diseases, the article delves into potential strategies to modify macrophage functionality and it also discusses emerging approaches to selectively target NLRP3 inflammasomes and their signaling components within the kidney, aiming to facilitate the healing process in kidney diseases.

Oleuropein attenuates the nephrotoxic effect of sunitinib in rats: Unraveling the potential role of SIRT6/Notch-1/NLRP-3/IL-1β axis

Sunitinib (SUN) is a chemotherapeutic agent clinically approved for treatment of metastatic renal carcinoma. Despite its remarkable benefits, various renal toxicities have been reported that limit its clinical uses. Oleuropein (OLE) is the main polyphenolic constituent of olive tree and mediates the majority of its valuable pharmacological activities. The current study examined the probable renoprotective effects of OLE against SUN-induced nephrotoxicity. Adult male albino rats were co-treated by SUN (25 mg/kg, 3 times/week, PO) with either a drug vehicle or OLE (60 mg/kg/day, daily, PO) for four weeks. A control group comprising of age-matched rats was used. Four weeks later, blood specimens were collected to assess kidney functions. Kidneys were harvested for biochemical and histopathological analyses. Administration of SUN induced kidney dysfunction, along with marked rises in endothelin-1 (ET-1) and monocyte chemotactic protein-1 (MCP-1) levels in renal tissues. Histological abnormalities were also detected in kidneys of SUN-treated rats including glomerular and tubular interstitial congestion along with interstitial fibrosis. On molecular levels, there was a decline in renal SIRT6 expression along with significant up-regulation of Notch-1, NLRP-3, interleukin -1β (IL-1β) and cleaved caspsase-3. All these changes were almost alleviated by OLE co-treatment. These findings suggest the implication of SIRT6/Notch-1/NLRP3/IL-1β axis in the pathogenesis of SUN-induced nephrotoxicity and highlight OLE as a prospective renoprotective agent during SUN chemotherapy to halt its renal toxicity likely through promotion of SIRT6 and suppression of Notch-1/NLRP3/IL-1β signaling pathway.

Berberine alleviated contrast-induced acute kidney injury by mitophagy-mediated NLRP3 inflammasome inactivation in a mice model

The incidence of contrast-induced acute kidney injury (CI-AKI) has escalated to become the third most prevalent cause of hospital-acquired AKI, with a lack of efficacious interventions. Berberine (BBR) possesses diverse pharmacological effects and exhibits renoprotective properties; however, limited knowledge exists regarding its impact on CI-AKI. Therefore, our study aimed to investigate the protective effects and underlying mechanisms of BBR on CI-AKI in a mice model, focusing on the nucleotide-binding oligomerization domain-like pyrin domain-containing protein 3 (NLRP3) inflammasome and mitophagy. The CI-AKI mice model was established by administering NG-nitro-L-arginine methyl ester (L-NAME) (10 mg/kg), indomethacin (10 mg/kg), and iohexol (11 g/kg) following water deprivation. A pretreatment of 100 mg/kg of BBR was orally administered to the mice for two weeks. Renal injury markers, damage-associated molecular patterns (DAMPs), renal histopathology, mitochondrial morphology, autophagosomes, and potential mechanisms were investigated. BBR effectively reduced levels of renal injury biomarkers such as serum cystatin C, urea nitrogen, and creatinine, downregulated the protein level of kidney injury molecule 1 (KIM1), and mitigated renal histomorphological damage. Moreover, BBR reduced DAMPs, including high mobility group box-1 (HMGB1), heat shock protein 70 (HSP70), and uric acid (UA). It also alleviated oxidative stress and inflammatory factors such as monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). Furthermore, the activation of NLRP3 inflammasome was attenuated in the BBR pretreatment group, as evidenced by both mRNA and protein levels. Electron microscopy and western blotting examination revealed that BBR mitigated mitochondrial damage and enhanced mitophagy. Additionally, BBR increased the P-AMPK/AMPK ratio. These findings indicated that BBR exerted a protective effect against CI-AKI by suppressing NLRP3 inflammasome activation and modulating mitophagy, providing a potential therapeutic strategy for its prevention.

The effects of NLRP3 inflammasome inhibition or knockout in experimental apical periodontitis induced in mice

OBJECTIVE

To evaluate the effects of NLRP3 inflammasome inhibition or knockout in experimental apical periodontitis (AP) induced in mice.

METHODS

The experimental AP was induced by pulpal exposure. To evaluate NLRP3-specific inhibitor medication (MCC950), WT mice received intraperitoneal injections, while the control received PBS (n = 10). In addition, to evaluate NLRP3 knockout, 35 wild-type (WT) and 35 NLRP3-/- mice were divided into a control group (without pulpal exposure, n = 5) and three experimental groups: after 2, 14 and 42 days after pulpal exposure (n = 10). Microscopic and molecular analyzes were carried out using a significance level of 5%.

RESULTS

Exposure to MCC950 did not affect the periapical lesion size after 14 days (P = 0.584). However, exposed mice had a lower expression of IL-1β, IL-18 and caspase-1 (P = 0.010, 0.016 and 0.002, respectively). Moreover, NLRP3-/- mice showed a smaller periapical lesion after 14 and 42 days (P = 0.023 and 0.031, respectively), as well as a lower expression of IL-1β after 42 days (P < 0.001), of IL-18 and caspase-1 after 14 (P < 0.001 and 0.035, respectively) and 42 days (P = 0.002 and 0.002, respectively). NLRP3-/- mice also showed a lower mRNA for Il-1β, Il-18 and Casp1 after 2 (P = 0.002, 0.036 and 0.001, respectively) and 14 days (P = 0.002, 0.002 and 0.001, respectively).

CONCLUSIONS

NLRP3 inflammasome inhibition or knockout can attenuate the inflammatory events that result in the periapical lesion (AP) formation after pulpal exposure in mice.

CLINICAL RELEVANCE

The NLRP3 inflammasome may be a therapeutic target for AP, and new approaches may verify the impact of its inhibition (through intracanal medications or filling materials) on the bone repair process and treatment success.

The case for a ketogenic diet in the management of kidney disease

Ketogenic diets have been widely used for weight loss and are increasingly used in the management of type 2 diabetes. Despite evidence that ketones have multiple positive effects on kidney function, common misconceptions about ketogenic diets, such as high protein content and acid load, have prevented their widespread use in individuals with impaired kidney function. Clinical trial evidence focusing on major adverse kidney events is sparse. The aim of this review is to explore the effects of a ketogenic diet, with an emphasis on the pleiotropic actions of ketones, on kidney health. Given the minimal concerns in relation to the potential renoprotective effects of a ketogenic diet, future studies should evaluate the safety and efficacy of ketogenic interventions in kidney disease.

The role of mitophagy in the development of chronic kidney disease

Chronic kidney disease (CKD) represents a significant global health concern, with renal fibrosis emerging as a prevalent and ultimate manifestation of this condition. The absence of targeted therapies presents an ongoing and substantial challenge. Accumulating evidence suggests that the integrity and functionality of mitochondria within renal tubular epithelial cells (RTECs) often become compromised during CKD development, playing a pivotal role in the progression of renal fibrosis. Mitophagy, a specific form of autophagy, assumes responsibility for eliminating damaged mitochondria to uphold mitochondrial equilibrium. Dysregulated mitophagy not only correlates with disrupted mitochondrial dynamics but also contributes to the advancement of renal fibrosis in CKD. While numerous studies have examined mitochondrial metabolism, ROS (reactive oxygen species) production, inflammation, and apoptosis in kidney diseases, the precise pathogenic mechanisms underlying mitophagy in CKD remain elusive. The exact mechanisms through which modulating mitophagy mitigates renal fibrosis, as well as its influence on CKD progression and prognosis, have not undergone systematic investigation. The role of mitophagy in AKI has been relatively clear, but the role of mitophagy in CKD is still rare. This article presents a comprehensive review of the current state of research on regulating mitophagy as a potential treatment for CKD. The objective is to provide fresh perspectives, viable strategies, and practical insights into CKD therapy, thereby contributing to the enhancement of human living conditions and patient well-being.

Activation of the Nrf2/ARE signaling pathway ameliorates hyperlipidemia-induced renal tubular epithelial cell injury by inhibiting mtROS-mediated NLRP3 inflammasome activation

Dyslipidemia is the most prevalent independent risk factor for patients with chronic kidney disease (CKD). Lipid-induced NLRP3 inflammasome activation in kidney-resident cells exacerbates renal injury by causing sterile inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that modulates the cellular redox balance; however, the exact role of Nrf2 signaling and its regulation of the NLRP3 inflammasome in hyperlipidemia-induced kidney injury are poorly understood. In this study, we demonstrated that activation of the mtROS-NLRP3 inflammasome pathway is a critical contributor to renal tubular epithelial cell (RTEC) apoptosis under hyperlipidemia. In addition, the Nrf2/ARE signaling pathway is activated in renal tubular epithelial cells under hyperlipidemia conditions both in vivo and in vitro, and Nrf2 silencing accelerated palmitic acid (PA)-induced mtROS production, mitochondrial injury, and NLRP3 inflammasome activation. However, the activation of Nrf2 with tBHQ ameliorated mtROS production, mitochondrial injury, NLRP3 inflammasome activation, and cell apoptosis in PA-induced HK-2 cells and in the kidneys of HFD-induced obese rats. Furthermore, mechanistic studies showed that the potential mechanism of Nrf2-induced NLRP3 inflammasome inhibition involved reducing mtROS generation. Taken together, our results demonstrate that the Nrf2/ARE signaling pathway attenuates hyperlipidemia-induced renal injury through its antioxidative and anti-inflammatory effects through the downregulation of mtROS-mediated NLRP3 inflammasome activation.

Contrast-induced acute kidney injury: a review of definition, pathogenesis, risk factors, prevention and treatment

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired AKI, which seriously threatens the health of patients. To date, the precise pathogenesis of CI-AKI has remained not clear and may be related to the direct cytotoxicity, hypoxia and ischemia of medulla, and oxidative stress caused by iodine contrast medium, which have diverse physicochemical properties, including cytotoxicity, permeability and viscosity. The latest research shows that microRNAs (miRNAs) are also involved in apoptosis, pyroptosis, and autophagy which caused by iodine contrast medium (ICM), which may be implicated in the pathogenesis of CI-AKI. Unfortunately, effective therapy of CI-AKI is very limited at present. Therefore, effective prevention of CI-AKI is of great significance, and several preventive options, including hydration, antagonistic vasoconstriction, and antioxidant drugs, have been developed. Here, we review current knowledge about the features of iodine contrast medium, the definition, pathogenesis, molecular mechanism, risk factors, prevention and treatment of CI-AKI.

Pyroptosis: The Determinator of Cell Death and Fate in Acute Kidney Injury

Background

Acute kidney injury (AKI) is kidney damage that leads to a rapid decline in function. AKI primarily occurs when the tubular epithelium is damaged, causing swelling, loss of brush margin, and eventual apoptosis. Research has shown that tubular epithelial cell damage in AKI is linked to cell cycle arrest, autophagy, and regulation of cell death.

Summary

Pyroptosis, a type of programmed cell death triggered by inflammation, is believed to play a role in the pathophysiology of AKI. Cumulative evidence has shown that pyroptosis is the main cause of tubular cell death in AKI. Thus, targeted intervention of pyroptosis may be a promising therapeutic approach for AKI. This review delves deep into the cutting-edge research surrounding pyroptosis in the context of AKI, shedding light on its intricate mechanisms and potential implications for clinical practice. Additionally, we explore the exciting realm of potential preclinical treatment options for AKI, aiming to pave the way for future therapeutic advancements.

Key Messages

Pyroptosis, a highly regulated form of cell death, plays a crucial role in determining the fate of cells during the development of AKI. This intricate process involves the activation of inflammasomes, which are multi-protein complexes that initiate pyroptotic cell death. By understanding the mechanisms underlying pyroptosis, researchers aim to gain insights into the pathogenesis of AKI and potentially identify new therapeutic targets for this condition.

The Angiotensin II Receptor Neprilysin Inhibitor LCZ696 Inhibits the NLRP3 Inflammasome By Reducing Mitochondrial Dysfunction in Macrophages and Alleviates Dextran Sulfate Sodium-induced Colitis in a Mouse Model

The intracellular sensor protein complex known as the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in regulating inflammatory diseases by overseeing the production of interleukin (IL)-1β and IL-18. Targeting its abnormal activation with drugs holds significant promise for inflammation treatment. This study highlights LCZ696, an angiotensin receptor-neprilysin inhibitor, as an effective suppressor of NLRP3 inflammasome activation in macrophages stimulated by ATP, nigericin, and monosodium urate. LCZ696 also reduces caspase-11 and GSDMD activation, lactate dehydrogenase release, propidium iodide uptake, and the extracellular release of NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in ATP-activated macrophages, suggesting a potential mitigation of pyroptosis. Mechanistically, LCZ696 lowers mitochondrial reactive oxygen species and preserves mitochondrial integrity. Importantly, it does not significantly impact NLRP3, proIL-1β, inducible nitric oxide synthase, cyclooxygenase-2 expression, or NF-κB activation in lipopolysaccharide-activated macrophages. LCZ696 partially inhibits the NLRP3 inflammasome through the induction of autophagy. In an in vivo context, LCZ696 alleviates NLRP3-associated colitis in a mouse model by reducing colonic expression of IL-1β and tumor necrosis factor-α. Collectively, these findings suggest that LCZ696 holds significant promise as a therapeutic agent for ameliorating NLRP3 inflammasome activation in various inflammatory diseases, extending beyond its established use in hypertension and heart failure treatment.

The intervention of cannabinoid receptor in chronic and acute kidney disease animal models: a systematic review and meta-analysis

AIM

Cannabinoid receptors are components of the endocannabinoid system that affect various physiological functions. We aim to investigate the effect of cannabinoid receptor modulation on kidney disease.

METHODS

PubMed, Web of Science databases, and EMBASE were searched. Articles selection, data extraction and quality assessment were independently performed by two investigators. The SYRCLE's RoB tool was used to assess the risk of study bias, and pooled SMD using a random-effect model and 95% CIs were calculated. Subgroup analyses were conducted in preselected subgroups, and publication bias was evaluated. We compared the effects of CB1 and CB2 antagonists and/or knockout and agonists and/or genetic regulation on renal function, blood glucose levels, body weight, and pathological damage-related indicators in different models of chronic and acute kidney injury.

RESULTS

The blockade or knockout of CB1 could significantly reduce blood urea nitrogen [SMD,- 1.67 (95% CI - 2.27 to - 1.07)], serum creatinine [SMD, - 1.88 (95% CI - 2.91 to - 0.85)], and albuminuria [SMD, - 1.60 (95% CI - 2.16 to - 1.04)] in renal dysfunction animals compared with the control group. The activation of CB2 group could significantly reduce serum creatinine [SMD, - 0.97 (95% CI - 1.83 to - 0.11)] and albuminuria [SMD, - 2.43 (95% CI - 4.63 to - 0.23)] in renal dysfunction animals compared with the control group.

CONCLUSIONS

The results suggest that targeting cannabinoid receptors, particularly CB1 antagonists and CB2 agonists, can improve kidney function and reduce inflammatory responses, exerting a renal protective effect and maintaining therapeutic potential in various types of kidney disease.

Comprehensive proteomics of monocytes indicates oxidative imbalance functionally related to inflammatory response in chronic kidney disease-related atherosclerosis

Atherosclerosis-induced cardiovascular events are the leading cause of mortality in chronic kidney disease (CKD) patients. Monocytes are involved in the formation of atherosclerotic plaques and mediate in the overproduction of ROS, promoting inflammation and oxidative stress. However, the relationship between monocytes, inflammation, and oxidative status in CKD-associated atherosclerosis has not been thoroughly investigated. Monocytes and plasma derived from two groups of CKD patients with varying degrees of atherosclerosis and two groups of patients with cardiovascular disease (CVD) and non-CKD atherosclerosis were analyzed. This study was designed to perform a comprehensive proteomic analysis of monocytes in combination with functional bioinformatics. In addition, a targeted investigation of oxidative stress- and inflammatory-related factors to explore CKD-associated atherosclerosis was applied. Dysregulation of proteins involved in lipid oxidation, cell survival, ROS synthesis and metabolism, and inflammatory responses has been revealed. The characteristic disturbances in the monocyte proteome changed with the progression of CKD. A closer examination of oxidative stress's triggers, mediators, and effects on protein and lipid levels showed alterations in the oxidative imbalance between CKD and CVD. CKD monocytes demonstrated a significant increase of oxidized glutathione without changing the level of its reduced form. Evaluation of enzymatic antioxidants, sources of ROS, and modifications caused by ROS also revealed significant alterations between the study groups. In CKD, inflammation and oxidative imbalance correlated and drove each other. However, in CVD, oxidative stress-related factors were associated with each other but not to inflammatory proteins. Moreover, lipid abnormalities were more specific to classical CVD and unrelated to CKD. Such a comprehensive characterization of monocytes and oxidative stress in CKD and CVD patients has never been presented so far. Obtained results support the involvement of distinct mechanisms underlying the acceleration of atherosclerotic and non-atherosclerotic CKD.

The role of a novel mineralocorticoid receptor antagonist, finerenone, in chronic kidney disease: mechanisms and clinical advances

BACKGROUND

Chronic kidney disease (CKD) poses a significant health risk in contemporary society. Current CKD treatments primarily involve renin-angiotensin-aldosterone system inhibitors and mineralocorticoid receptor antagonists, albeit associated with hyperkalemia risks. A novel selective mineralocorticoid receptor antagonist, finerenone, offers a promising, safer alternative for CKD therapy. This review comprehensively assesses the role and efficacy of finerenone in CKD treatment by analyzing clinical and animal studies. Emerging evidence consistently supports finerenone's ability to effectively slow the progression of CKD. By targeting the mineralocorticoid receptor, finerenone not only mitigates renal damage but also exhibits a favorable safety profile, minimizing hyperkalemia concerns.

CONCLUSION

Finerenone emerges as a valuable addition to CKD therapy, demonstrating potential benefits in delaying CKD progression while minimizing side effects. Nevertheless, further clinical trials are necessary to provide a comprehensive understanding of its safety and efficacy.

Sesamin-mediated high expression of BECN2 ameliorates cartilage endplate degeneration by reducing autophagy and inflammation

Lumbar disc degeneration (LDD) is a prevalent clinical spinal disease characterized by the calcification and degeneration of the cartilage endplate (CEP), which significantly reduces nutrient supply to the intervertebral disc. Traditional Chinese medicine offers a conservative and effective approach for treating LDD. We aimed to investigate the molecular mechanisms underlying the therapeutic effects of Sesamin in LDD treatment. Transcriptome sequencing was used to analyze the effect of Sesamin on LPS-induced ATDC5. We explored the role of BECN2, a target gene of Sesamin, in attenuating LPS-induced degeneration of ATDC5 cells. Our results revealed the identification of 117 differentially expressed genes (DEGs), with 54 up-regulated and 63 down-regulated genes. Notably, Sesamin significantly increased the expression of BECN2 in LPS-induced ATDC5 cell degeneration. Overexpressed BECN2 enhanced cell viability and inhibited cell apoptosis in LPS-induced ATDC5 cells, while BECN2 knockdown reduced cell viability and increased apoptosis. Furthermore, BECN2 played a crucial role in attenuating chondrocyte degeneration by modulating autophagy and inflammation. Specifically, BECN2 suppressed autophagy by reducing the expression of ATG14, VPS34, and GASP1, and alleviated the inflammatory response by decreasing the expression of inflammasome proteins NLRP3, NLRC4, NLRP1, and AIM2. In vivo experiments further supported the beneficial effects of Sesamin in mitigating LDD. This study provides novel insights into the potential molecular mechanism of Sesamin in treating LDD, highlighting its ability to mediate autophagy and inflammation inhibition via targeting the BECN2. This study provides a new therapeutic strategy for the treatment of LDD, as well as a potential molecular target for LDD.

Understanding the podocyte immune responses in proteinuric kidney diseases: from pathogenesis to therapy

The glomerular filtration barrier, comprising the inner layer of capillary fenestrated endothelial cells, outermost podocytes, and the glomerular basement membrane between them, plays a pivotal role in kidney function. Podocytes, terminally differentiated epithelial cells, are challenging to regenerate once injured. They are essential for maintaining the integrity of the glomerular filtration barrier. Damage to podocytes, resulting from intrinsic or extrinsic factors, leads to proteinuria in the early stages and eventually progresses to chronic kidney disease (CKD). Immune-mediated podocyte injury is a primary pathogenic mechanism in proteinuric glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and lupus nephritis with podocyte involvement. An extensive body of evidence indicates that podocytes not only contribute significantly to the maintenance of the glomerular filtration barrier and serve as targets of immune responses but also exhibit immune cell-like characteristics, participating in both innate and adaptive immunity. They play a pivotal role in mediating glomerular injury and represent potential therapeutic targets for CKD. This review aims to systematically elucidate the mechanisms of podocyte immune injury in various podocyte lesions and provide an overview of recent advances in podocyte immunotherapy. It offers valuable insights for a deeper understanding of the role of podocytes in proteinuric glomerular diseases, and the identification of new therapeutic targets, and has significant implications for the future clinical diagnosis and treatment of podocyte-related disorders.

Targeting fusion proteins of the interleukin family: A promising new strategy for the treatment of autoinflammatory diseases

As a means of communication between immune cells and non-immune cells, Interleukins (ILs) has the main functions of stimulating the proliferation and activation of inflammatory immune cells such as dendritic cells and lymphocytes, promote the development of blood cells and so on. However, dysregulation of ILs expression is a major feature of autoinflammatory diseases. The drugs targeting ILs or IL-like biologics have played an important role in the clinical treatment of autoinflammatory diseases. Nevertheless, the widespread use of IL products may result in significant off-target adverse reactions. Thus, there is a clear need to develop next-generation ILs products in the biomedical field. Fusion proteins are proteins created through the joining of two or more genes that originally coded for separate proteins. Over the last 30 years, there has been increasing interest in the use of fusion protein technology for developing anti-inflammatory drugs. In comparison to single-target drugs, fusion proteins, as multiple targets drugs, have the ability to enhance the cytokine therapeutic index, resulting in improved efficacy over classical drugs. The strategy of preparing ILs or their receptors as fusion proteins is increasingly used in the treatment of autoimmune and chronic inflammation. This review focuses on the efficacy of several fusion protein drugs developed with ILs or their receptors in the treatment of autoinflammatory diseases, in order to illustrate the prospects of this new technology as an anti-inflammatory drug development protocol in the future.

C3a/C3aR synergies with TGF-β to promote epithelial-mesenchymal transition of renal tubular epithelial cells via the activation of the NLRP3 inflammasome

BACKGROUND

Complement component 3a and its receptor (C3a/C3aR) and the nucleotide-binding oligomerization domain-like receptor protein-3 (NLRP3) inflammasome contribute to epithelial-mesenchymal transition (EMT). However, the relationship between C3a/C3aR and the NLRP3 inflammasome in EMT remains unclear. This study aimed to elucidate the roles of C3a/C3aR and the NLRP3 inflammasome involved in TGF-β-induced EMT.

METHOD

Mouse renal tubular epithelial cells (TCMK-1) were exposed to C3a and TGF-β for 48 h. C3aR antagonist, MCC950, an inhibitor of the NLRP3 inflammasome and PD98059, an inhibitor of ERK signaling, were respectively applied to pretreat the cells at 30 min before C3a and TGF-β administration.The cells were collected for western blot, immunofluorescence staining and ELISA. Unilateral ureteral obstruction (UUO) models were established using male C57BL/6 wild-type (WT) mice and age-matched C3aR-deficient mice. MCC950 was intraperitoneally injected in UUO mice. Kidney samples were collected for immunohistochemistry staining.

RESULTS

In vitro, C3a synergized with TGF-β to promote EMT and the activation of the NLRP3 inflammasome. Inhibition of C3aR attenuated EMT and the activation of the NLRP3 inflammasome. Inhibition of the NLRP3 inflammasome alleviated EMT but didn't affect the expression of C3aR. Inhibition of ERK signaling inhibited the activation of the NLRP3 inflammasome. In vivo, the expression of IL-1β was significantly higher in UUO mice compared to the sham-operated mice. C3aR deficiency and inhibition of the NLRP3 Inflammasome contributed to decreased IL-1β in UUO mice.

CONCLUSION

Our data revealed that C3a/C3aR synergies with TGF-β to activate the NLRP3 inflammasome to promote epithelial-mesenchymal transition of renal tubular epithelial cells through ERK signaling, and the way in which C3aR activates the inflammasome is to promote the assembly of the NLRP3 inflammasome.

Gbp3 is associated with the progression of lupus nephritis by regulating cell proliferation, inflammation and pyroptosis

Lupus nephritis (LN) is a major cause death in patients with systemic lupus erythematosus. We aimed to find the differentially expressed genes (DEGs) in LN and confirm the regulatory mechanism on LN. The mouse model of LN was constructed by subcutaneous injection of pristane. RNA-seq screened 392 up-regulated and 447 down-regulated DEGs in LN mouse model, and KEGG analysis found that the top 20 DEGs were enriched in arachidonic acid metabolism, tryptophan metabolism, etc. The hub genes, Kynu, Spidr, Gbp3, Cbr1, Cyp4b1, and Cndp2 were identified, in which Gbp3 was selected for following study. Afterwards, the function of Gbp3 on the proliferation, inflammation, and pyroptosis of LN was verified by CCK-8, ELISA, and WB in vitro. The results demonstrated that si-Gbp3 promoted cell proliferation and inhibited the levels of inflammatory factors (IL-1β, TNF-α and IL-8) and pyroptosis-related proteins (GSDMD, Caspase-1 and NLRP3) in a cell model of LN. In constrast, Gbp3 overexpression played an opposite role. In summary, Gbp3 promoted the progression of LN via inhibiting cell proliferation and facilitating inflammation and pyroptosis.

Fluorofenidone Attenuates Renal Interstitial Fibrosis by Enhancing Autophagy and Retaining Mitochondrial Function

BACKGROUND

Fluorofenidone (AKF-PD) is a novel pyridone agent and has potent anti-NLRP3 inflammasome and anti-fibrotic activities. However, the mechanisms underlying its pharmacological actions are not fully understood.

METHODS

A renal fibrosis rat model was established by the unilateral ureteral obstruction (UUO) procedure and the rats were randomized and treated with, or without, AKF-PD for 3 and 7 days. The levels of renal fibrosis, NLRP3 inflammasome activation, mitochondrial function, and autophagy were tested in rat kidney tissues. Macrophages following lipopolysaccharides (LPS) and adenosine 5'-triphosphate (ATP) stimulation were examined by Western blot, spectrophotometry, and TEM.

RESULTS

Compared with the untreated UUO rats, AKF-PD treatment significantly mitigated the UUO procedure-induced renal fibrosis in rats. AKF-PD treatment decreased mitochondrial dysfunction and IL-Iβ and caspase-1 expression in rat kidney tissues and reduced mitochondrial reactive oxygen species production in activated macrophages. Mechanistically, AKF-PD treatment significantly attenuated the PI3K/AKT/mTOR signaling, increased Beclin-1 and LC3 II expression and autophagosome formation, and ameliorated the mitochondrial damage in renal tissues and activated macrophages.

CONCLUSION

The results indicated that AKF-PD treatment inhibited renal interstitial fibrosis by regulating the autophagy-mitochondria-NLRP3 inflammasome pathway.

Puerarin protects renal ischemia-reperfusion injury in rats through NLRP3/Caspase-1/GSDMD pathway

PURPOSE

To observe the effect of puerarin on renal ischemia-reperfusion (I/R) injury in rats, and to explore its mechanism based on NLRP3/Caspase-1/GSDMD pathway.

METHODS

Twenty-one Sprague-Dawley rats were divided into three groups: sham-operated group (sham), model group (RIRI), and puerarin treatment group (RIRI + Pue). The model of acute renal I/R injury was established by cutting the right kidney and clamping the left renal pedicle for 45 min.

RESULTS

Renal function parameters were statistically significant in group comparisons. The renal tissue structure of rats in sham group was basically normal. Pathological changes were observed in the RIRI group. The renal pathological damage score and apoptosis rate in the RIRI group were higher than those in the sham group, and significantly lower in the RIRI + Pue group than in the RIRI group. Indicators of oxidative stress-superoxide dismutase, malondialdehyde, and glutathione peroxidase-were statistically significant in group comparisons. Compared with the sham group, the relative expressions of NLRP3, Caspase-1 and GSDMD proteins in the RIRI group were increased. Compared with the RIRI group, the RIRI + Pue group had significant reductions.

CONCLUSIONS

Puerarin can inhibit the activation of NLRP3/Caspase-1/GSDMD pathway, inhibit inflammatory response and pyroptosis, and enhance the antioxidant capacity of kidney, thereby protecting renal I/R injury in rats.

Vaccarin alleviates cisplatin-induced acute kidney injury via decreasing NOX4-derived ROS

Cisplatin is a chemotherapeutant widely used in treating solid tumors, with the common side effect of acute kidney injury (AKI). Developing effective useful agent for preventing or treating cisplatin-induced AKI is of great importance. In this study, we investigate the protective effect of vaccarin, a chemical entity of flavonoid glycoside, against cisplatin-induced AKI. Cisplatin-treated C57BL/6J mice and human kidney-2 (HK-2) cells were used as the model of cisplatin-induced AKI. The levels of blood urea nitrogen (BUN) and creatine (Cr) levels and periodic acid-Schiff staining (PAS) scores decreased when vaccarin was administrated. Vaccarin had no impact on renal platinum accumulation, which was detected by the ICP-MS 6 h after cisplatin injection. Moreover, vaccarin can significantly alleviate the product of reactive oxygen species and the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) in cisplatin-induced AKI, both in vivo and in vitro. In addition, vaccarin decreased the receptor-interacting protein kinase 1 (RIPK1) related programmed necrosis (necroptosis), cell apoptosis (shown by the protein levels of cleaved-caspase3 and flow cytometry) and inflammation (shown by the decreased levels of NLRP3, p-P65 and the mRNA of several inflammatory factors). NOX4 inhibitor GLX351322 (GLX) and NOX4 kowndown by siRNA have equivalent protective effect of vaccarin in vitro. When vaccarin was administered together with GLX or NOX4 siRNA, this protective effect of vaccarin did not further increase, as indicating by the index of oxidative stress, cell viability, necroptosis and apoptosis. In conclusion, vaccarin can alleviate cisplatin-induced AKI via inhibiting NOX4.

Exploring the significance of interleukin-33/ST2 axis in minimal change disease

Minimal change disease (MCD), a common cause of idiopathic nephrotic syndrome, has been postulated to exhibit an association with allergic conditions. Recent studies revealed the crucial role of interleukin (IL)-33 in type 2 innate immunity. We hypothesized that development of MCD involves an IL-33-related immune response. We examined 49 patients with biopsy-proven MCD, 6 healthy volunteers, and 29 patients in remission. In addition to clinical features, serum and urinary levels of IL-33 and soluble suppression of tumorigenicity 2 protein (sST2), a secreted form of the receptor of IL-33, were analyzed. Although IL-33 was barely detectable in either MCD or control samples, sST2 levels at diagnosis were elevated in MCD patients. Serum sST2 levels of MCD patients were correlated with serum total protein level (r =  - 0.36, p = 0.010) and serum creatinine level (r = 0.34, p = 0.016). Furthermore, the elevated sST2 levels were observed to decrease following remission. Immunofluorescence revealed IL-33 expression in the podocytes among MCD patients, with a significant increase compared with controls. In vitro, mouse podocyte cells incubated with serum from a MCD patient at disease onset showed increased IL-33 secretion. These results suggest an IL-33-related immune response plays a role in MCD.

The intellectual base and global trends in inflammation of diabetic kidney disease: a bibliometric analysis

Diabetic kidney disease (DKD) is a severe complication of diabetes mellitus (DM). The literature on DKD inflammation research has experienced substantial growth. However, there is a lack of bibliometric analyses. This study aimed to examine the existing research on inflammation in DKD by analyzing articles published in the Web of Science Core Collection (WOSCC) over the past 30 years. We conducted a visualization analysis using several software, including CiteSpace and VOSviewer. We found that the literature on inflammation research in DKD has experienced substantial growth, indicating a rising interest in this developing area of study. In this field, Navarro-Gonzalez, JF is the most frequently cited author, Kidney International is the most frequently cited journal, China had the highest number of publications in the field of DKD inflammation, and Monash University emerged as the institution with the most published research. The research area on inflammation in DKD primarily centers around the investigation of 'Glycation end-products', 'chronic kidney disease', and 'diabetic nephropathy'. The emerging research trends in this field will focus on the 'Gut microbiota', 'NLRP3 inflammasome', 'autophagy', 'pyroptosis', 'sglt2 inhibitor', and 'therapeutic target'. Future research on DKD may focus on further exploring the inflammatory response, identifying specific therapeutic targets, studying biomarkers, investigating stem cell therapy and tissue engineering, and exploring gene therapy and gene editing. In summary, this study examines the main areas of study, frontiers, and trends in DKD inflammation, which have significant implications for future research.

VEGFC ameliorates salt-sensitive hypertension and hypertensive nephropathy by inhibiting NLRP3 inflammasome via activating VEGFR3-AMPK dependent autophagy pathway

Salt-sensitivity hypertension (SSHTN) is an independent predictor for cardiovascular mortality. VEGFC has been reported to be a protective role in SSHTN and hypertensive kidney injury. However, the underlying mechanisms remain largely unclear. The current study aimed to explore the protective effects and mechanisms of VEGFC against SSHTN and hypertensive nephropathy. Here, we reported that VEGFC attenuated high blood pressure as well as protected against renal inflammation and fibrosis in SSHTN mice. Moreover, VEGFC suppressed the activation of renal NLRP3 inflammasome in SSHTN mice. In vitro, we found VEGFC inhibited NLRP3 inflammasome activation, meanwhile, upregulated autophagy in high-salt-induced macrophages, while these effects were reversed by an autophagy inhibitor 3MA. Furthermore, in vivo, 3MA pretreatment weakened the protective effects of VEGFC on SSHTN and hypertensive nephropathy. Mechanistically, VEGF receptor 3 (VEGFR3) kinase domain activated AMPK by promoting the phosphorylation at Thr183 via binding to AMPK, thus enhancing autophagy activity in the context of high-salt-induced macrophages. These findings indicated that VEGFC inhibited NLRP3 inflammasome activation by promoting VEGFR3-AMPK-dependent autophagy pathway in high-salt-induced macrophages, which provided a mechanistic basis for the therapeutic target in SSHTN and hypertensive kidney injury.

Novel Therapeutic Approaches in the Management of Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive and incurable disease that impairs kidney function. Its prevalence is estimated to affect up to 800 million individuals within the general population, and patients with diabetes and hypertension are particularly at risk. This disorder disrupts the physiological mechanisms of the body, including water and electrolyte balance, blood pressure regulation, the excretion of toxins, and vitamin D metabolism. Consequently, patients are exposed to risks such as hyperkalemia, hyperphosphatemia, metabolic acidosis, and blood pressure abnormalities. These risks can be reduced by implementing appropriate diagnostic methods, followed by non-pharmacological (such as physical activity, dietary, and lifestyle adjustment) and pharmacological strategies after diagnosis. Selecting the appropriate diet and suitable pharmacological treatment is imperative in maintaining kidney function as long as possible. Drugs such as finerenone, canakinumab, and pentoxifylline hold promise for improved outcomes among CKD patients. When these interventions prove insufficient, renal replacement therapy becomes essential. This is particularly critical in preserving residual renal function while awaiting renal transplantation or for patients deemed ineligible for such a procedure. The aim of this study is to present the current state of knowledge and recent advances, providing novel insights into the treatment of chronic kidney disease.

Chronic kidney disease promotes atrial fibrillation via inflammasome pathway activation

Chronic kidney disease (CKD) is associated with a higher risk of atrial fibrillation (AF). The mechanistic link between CKD and AF remains elusive. IL-1β, a main effector of NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation, is a key modulator of conditions associated with inflammation, such as AF and CKD. Circulating IL-1β levels were elevated in patients with CKD who had AF (versus patients with CKD in sinus rhythm). Moreover, NLRP3 activity was enhanced in atria of patients with CKD. To elucidate the role of NLRP3/IL-1β signaling in the pathogenesis of CKD-induced AF, Nlrp3-/- and WT mice were subjected to a 2-stage subtotal nephrectomy protocol to induce CKD. Four weeks after surgery, IL-1β levels in serum and atrial tissue were increased in WT CKD (WT-CKD) mice versus sham-operated WT (WT-sham) mice. The increased susceptibility to pacing-induced AF and the longer AF duration in WT-CKD mice were associated with an abbreviated atrial effective refractory period, enlarged atria, and atrial fibrosis. Genetic inhibition of NLRP3 in Nlrp3-/- mice or neutralizing anti-IL-1β antibodies effectively reduced IL-1β levels, normalized left atrial dimensions, and reduced fibrosis and the incidence of AF. These data suggest that CKD creates a substrate for AF development by activating the NLRP3 inflammasome in atria, which is associated with structural and electrical remodeling. Neutralizing IL-1β antibodies may be beneficial in preventing CKD-induced AF.

A novel pyroptosis-related signature predicts prognosis and indicates immunotherapy in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) has been recognized as a frequently occurring oral malignant tumor. Pyroptosis plays an extremely important role in the occurrence and development of cancer, but the role of pyroptosis in OSCC remains unclear.

METHODS

OSCC-related data were obtained from the TCGA and GEO databases. A PSscore risk model was constructed through LASSO regression analysis. The GEO database was utilized as the validation set of the model. The "ESTIMATE" and "CIBERSORT" algorithms were utilized to additionally evaluate the relationship between the immune cell score and PSscore. TIDE and IPS algorithms were used to assess patient response to immunotherapy. In addition, Western blot analysis and MTT assay was used to further validate key genes.

RESULTS

Comprehensive bioinformatics analysis showed that a low-PSscore had a significant survival advantage, richer immune cell infiltration, more active immune-related pathways, higher TME scores, and lower tumor purity. The results of TIDE and IPS analysis indicated that the high-PSscore group had higher immune escape potential and was less sensitive to immunotherapy. In contrast, the low-PSscore group patients might be more sensitive to PD1 and CTLA4 + PD1 immunotherapy. Univariate and multivariate COX results indicated that PSscore was an independent prognostic factor in OSCC patients. Another important finding is that BAK1 is a potential target of OSCC and is related to the Nod-like receptor signaling pathway. Knockdown of BAK1 can significantly reduce the proliferation of OSCC cells.

CONCLUSION

The PSscore model could be utilized as a powerful prognostic indicator and can help in the development of new immunotherapies.

Rosmarinic acid nanomedicine for rheumatoid arthritis therapy: Targeted RONS scavenging and macrophage repolarization

The infiltration of inflammatory cells, especially macrophages, integrated with the production of reactive oxygen and nitrogen species (RONS) and the release of inflammatory cytokines play a crucial role in the pathogenesis of rheumatoid arthritis (RA). Synergistic combination of RONS scavenging and macrophage repolarization from pro-inflammatory M1 phenotype towards anti-inflammatory M2 phenotype, provides a promising strategy for efficient RA treatment. Herein, this study reported a unique self-assembly strategy to construct distinct rosmarinic acid nanoparticles (RNPs) for efficient RA treatment using the naturally occurring polyphenol-based compound, rosmarinic acid (RosA). The designed RNPs exhibited favorable capability in scavenging RONS and pro-inflammatory cytokines produced by macrophages. Attributing to the widened vascular endothelial-cell gap at inflammation sites, RNPs could target and accumulate at the inflammatory joints of collagen-induced arthritis (CIA) rats for guaranteeing therapeutic effect. In vivo investigation demonstrated that RNPs alleviated the symptoms of RA, including joint swelling, synovial hyperplasia, cartilage degradation, and bone erosion in CIA rats. Additionally, the designed RNPs promoted macrophage polarization from M1 phenotype towards M2 phenotype, resulting in the suppressed progression of RA. Therefore, this research represents the representative paradigm for RA therapy using antioxidative nanomedicine deriving from the natural polyphenol-based compound.

Identifying Aging-Related Biomarkers and Immune Infiltration Features in Diabetic Nephropathy Using Integrative Bioinformatics Approaches and Machine-Learning Strategies

BACKGROUND

Aging plays an essential role in the development of diabetic nephropathy (DN). This study aimed to identify and verify potential aging-related genes associated with DN using bioinformatics analysis.

METHODS

To begin with, we combined the datasets from GEO microarrays (GSE104954 and GSE30528) to find the genes that were differentially expressed (DEGs) across samples from DN and healthy patient populations. By overlapping DEGs, weighted co-expression network analysis (WGCNA), and 1357 aging-related genes (ARGs), differentially expressed ARGs (DEARGs) were discovered. We next performed functional analysis to determine DEARGs' possible roles. Moreover, protein-protein interactions were examined using STRING. The hub DEARGs were identified using the CytoHubba, MCODE, and LASSO algorithms. We next used two validation datasets and Receiver Operating Characteristic (ROC) curves to determine the diagnostic significance of the hub DEARGs. RT-qPCR, meanwhile, was used to confirm the hub DEARGs' expression levels in vitro. In addition, we investigated the relationships between immune cells and hub DEARGs. Next, Gene Set Enrichment Analysis (GSEA) was used to identify each biomarker's biological role. The hub DEARGs' subcellular location and cell subpopulations were both identified and predicted using the HPA and COMPARTMENTS databases, respectively. Finally, drug-protein interactions were predicted and validated using STITCH and AutoDock Vina.

RESULTS

A total of 57 DEARGs were identified, and functional analysis reveals that they play a major role in inflammatory processes and immunomodulation in DN. In particular, aging and the AGE-RAGE signaling pathway in diabetic complications are significantly enriched. Four hub DEARGs (CCR2, VCAM1, CSF1R, and ITGAM) were further screened using the interaction network, CytoHubba, MCODE, and LASSO algorithms. The results above were further supported by validation sets, ROC curves, and RT-qPCR. According to an evaluation of immune infiltration, DN had significantly more resting mast cells and delta gamma T cells but fewer regulatory T cells and active mast cells. Four DEARGs have statistical correlations with them as well. Further investigation revealed that four DEARGs were implicated in immune cell abnormalities and regulated a wide range of immunological and inflammatory responses. Furthermore, the drug-protein interactions included four possible therapeutic medicines that target four DEARGs, and molecular docking could make this association practical.

CONCLUSIONS

This study identified four DEARGs (CCR2, VCAM1, CSF1R, and ITGAM) associated with DN, which might play a key role in the development of DN and could be potential biomarkers in DN.

Sepsis-mediated renal dysfunction: Pathophysiology, biomarkers and role of phytoconstituents in its management

Sepsis has evolved as an enormous health issue amongst critically ill patients. It is a major risk factor that results in multiple organ failure and shock. Acute kidney injury (AKI) is one of the most frequent complications underlying sepsis, which portends a heavy burden of mortality and morbidity. Thus, the present review is aimed to provide an insight into the recent progression in the molecular mechanisms targeting dysregulated immune response and cellular dysfunction involved in the development of sepsis-associated AKI, accentuating the phytoconstituents as eligible candidates for attenuating the onset and progression of sepsis-associated AKI. The pathogenesis of sepsis-mediated AKI entails a complicated mechanism and is likely to involve a distinct constellation of hemodynamic, inflammatory, and immune mechanisms. Novel biomarkers like neutrophil gelatinase-associated lipocalin, soluble triggering receptor expressed on myeloid cells 1, procalcitonin, alpha-1-microglobulin, and presepsin can help in a more sensitive diagnosis of sepsis-associated AKI. Many bioactive compounds like curcumin, resveratrol, baicalin, quercetin, and polydatin are reported to play an important role in the prevention and management of sepsis-associated AKI by decreasing serum creatinine, blood urea nitrogen, cystatin C, lipid peroxidation, oxidative stress, IL-1β, TNF-α, NF-κB, and increasing the activity of antioxidant enzymes and level of PPARγ. The plant bioactive compounds could be developed into a drug-developing candidate in managing sepsis-mediated acute kidney injury after detailed follow-up studies. Lastly, the gut-kidney axis may be a more promising therapeutic target against the onset of septic AKI, but a deeper understanding of the molecular pathways is still required.

Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition on Podocytes in Mouse Nephrotic Syndrome

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is known to play a crucial role in dyslipidemia, and an increase in serum PCSK9 levels has also been reported in patients with nephrotic syndrome (NS). However, the specific effects of PCSK9 in kidney disease and the therapeutic potential of targeting PCSK9 in NS remain elusive. We thus investigated the effects of evolocumab (EVO) in mice with adriamycin (ADR)-induced NS. Male BALB/c mice were divided into the following 4 groups: Control, N = 11; EVO (monoclonal antibody for PCSK9), N = 11; ADR, N = 11; and ADR+EVO, N = 11. We also performed in vitro experiments using immortalized murine podocyte cells to validate the direct effects of PCSK9 on podocytes. EVO decreased urinary albumin levels and ameliorated podocytopathy in mice with ADR nephropathy. Further, EVO suppressed the Nod-like receptor protein 3 (NLRP3) inflammasome pathway in podocytes. PCSK9 expression upregulated CD36, a scavenger receptor of oxidized low-density lipoprotein (Ox-LDL), which in turn stimulated the absorption of Ox-LDL in vitro. EVO downregulated CD36 expression in podocytes both in vitro and in vivo. Immunofluorescence staining analysis reveals that CD36 and PCSK9 colocalized in the glomerular tufts of mice with ADR nephropathy. In the patients with focal segmental glomerulosclerosis, the CD36+ area in glomerular tufts increased compared with those diagnosed with minor glomerular abnormalities. This study revealed that EVO ameliorated mouse ADR nephropathy through the regulation of CD36 and NLRP3 inflammasome signaling. EVO treatment represents a potential therapeutic strategy for human NS.

Roles of pyroptosis in intervertebral disc degeneration

Intervertebral disc degeneration (IDD), the key pathological process in low back pain, is characterized by chronic inflammation and progressive cell death. Pyroptosis is a type of pro-inflammatory programmed necrosis mediated by inflammasomes that is dependent on the gasdermin family of proteins. An in-depth study of the pathological mechanisms of IDD has revealed that pyroptosis plays an important role in its occurrence and development. The molecular characteristics and activation signaling mechanisms of pyroptosis are reviewed in this paper. Moreover, the specific roles of pyroptosis in IDD pathology are outlined and various targeted drugs for its treatment are highlighted.

Inhibiting NLRP3 signaling in aging podocytes improves their life- and health-span

The decrease in the podocyte's lifespan and health-span that typify healthy kidney aging cause a decrease in their normal structure, physiology and function. The ability to halt and even reverse these changes becomes clinically relevant when disease is superimposed on an aged kidney. RNA-sequencing of podocytes from middle-aged mice showed an inflammatory phenotype with increases in the NLRP3 inflammasome, signaling for IL2/Stat5, IL6 and TNF, interferon gamma response, allograft rejection and complement, consistent with inflammaging. Furthermore, injury-induced NLRP3 signaling in podocytes was further augmented in aged mice compared to young ones. The NLRP3 inflammasome (NLRP3, Caspase-1, IL1β IL-18) was also increased in podocytes of middle-aged humans. Higher transcript expression for NLRP3 in human glomeruli was accompanied by reduced podocyte density and increased global glomerulosclerosis and glomerular volume. Pharmacological inhibition of NLRP3 with MCC950, or gene deletion, reduced podocyte senescence and the genes typifying aging in middle-aged mice, which was accompanied by an improved podocyte lifespan and health-span. Moreover, modeling the injury-dependent increase in NLRP3 signaling in human kidney organoids confirmed the anti-senescence effect of MC9950. Finally, NLRP3 also impacted liver aging. Together, these results suggest a critical role for the NLRP3 inflammasome in podocyte and liver aging.

STING deletion alleviates podocyte injury through suppressing inflammation by targeting NLRP3 in diabetic kidney disease

An increasing number of studies have shown that immune inflammatory response plays a vital role in diabetic kidney disease (DKD). Nod-like receptor protein 3 (NLRP3) inflammasome-dependent inflammatory response is a key mechanism in the initiation and development of DKD. The stimulator of interferon genes (STING) is an adaptor protein that can drive noninfectious inflammation and pyroptosis. However, the mechanism of STING regulating immune inflammation and the interaction with NLRP3-dependent pyroptosis in high glucose state still remains unclear. This study evaluated the potential role of STING in high glucose (HG)-induced podocyte inflammation response. STING expression was significantly increased in db/db mice, STZ-treated diabetic mice, and HG-treated podocytes. Podocyte-specific deletion of STING alleviated podocyte injury, renal dysfunction, and inflammation in STZ-induced diabetic mice. STING inhibitor (H151) administration ameliorated inflammation and improved renal function in db/db mice. STING deletion in podocytes attenuated the activation of the NLRP3 inflammasome and podocyte pyroptosis in STZ-induced diabetic mice. In vitro, modulated STING expression by STING siRNA alleviated pyroptosis and NLRP3 inflammasome activation in HG-treated podocytes. NLRP3 over-expression offset the beneficial effects of STING deletion. These results indicate that STING deletion suppresses podocyte inflammation response through suppressing NLRP3 inflammasome activation and provide evidence that STING may be a potential target for podocyte injury in DKD.

Possible therapeutic targets for NLRP3 inflammasome-induced breast cancer

Inflammation plays a major role in the development and progression of breast cancer(BC). Proliferation, invasion, angiogenesis, and metastasis are all linked to inflammation and tumorigenesis. Furthermore, tumor microenvironment (TME) inflammation-mediated cytokine releases play a critical role in these processes. By recruiting caspase-1 through an adaptor apoptosis-related spot protein, inflammatory caspases are activated by the triggering of pattern recognition receptors on the surface of immune cells. Toll-like receptors, NOD-like receptors, and melanoma-like receptors are not triggered. It activates the proinflammatory cytokines interleukin (IL)-1β and IL-18 and is involved in different biological processes that exert their effects. The Nod-Like Receptor Protein 3 (NLRP3) inflammasome regulates inflammation by mediating the secretion of proinflammatory cytokines and interacting with other cellular compartments through the inflammasome's central role in innate immunity. NLRP3 inflammasome activation mechanisms have received much attention in recent years. Inflammatory diseases including enteritis, tumors, gout, neurodegenerative diseases, diabetes, and obesity are associated with abnormal activation of the NLRP3 inflammasome. Different cancer diseases have been linked to NLRP3 and its role in tumorigenesis may be the opposite. Tumors can be suppressed by it, as has been seen primarily in the context of colorectal cancer associated with colitis. However, cancers such as gastric and skin can also be promoted by it. The inflammasome NLRP3 is associated with breast cancer, but there are few specific reviews. This review focuses on the structure, biological characteristics and mechanism of inflammasome, the relationship between NLRP3 in breast cancer Non-Coding RNAs, MicroRNAs and breast cancer microenvironment, especially the role of NLRP3 in triple-negative breast cancer (TNBC). And the potential strategies of using NLRP3 inflammasome to target breast cancer, such as NLRP3-based nanoparticle technology and gene target therapy, are reviewed.

Chloroquine inhibits NLRP3 inflammasomes activation and alleviates renal fibrosis in mouse model of hyperuricemic nephropathy with aggravation by a high-fat-diet

Numerous epidemiological studies have demonstrated that hyperuricemia (HUA) is a risk factor for renal diseases and renal fibrosis. Dietary patterns can influence serum urate levels and hyperuricemic nephropathy (HN). NLRP3 inflammasomes play a crucial role in various inflammatory responses and contribute to HN progression. Chloroquine (CQ) is an anti-inflammatory and disease-modifying anti-rheumatic drug (DMARD) utilized in treating autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. In this study, we examined the effects and underlying mechanisms of CQ in a high-fat-diet (HFD) exacerbated mouse model of HN. C57BL/6 mice were randomized into either a control group or an HN group (induced by adenine/potassium oxonate treatment), followed by a normal diet or HFD, with or without CQ treatment. Our findings revealed that the HN group exhibited elevated serum levels of blood urea nitrogen (BUN) and creatinine compared to the control group. Additionally, the HN + HFD group displayed increased serum levels of uric acid, BUN, and creatinine relative to the control + HFD group. Moreover, the HFD exacerbated renal uric acid crystal deposition and fibrosis in HN mice compared to a normal diet. CQ ameliorated renal dysfunction, as evidenced by reduced serum creatinine levels, renal fibrosis, and renal tubular injury scores, and significantly decreased NLRP3, ASC, caspase-1, and IL-1β levels in HN mice. These findings suggest that CQ inhibits the activation of NLRP3 inflammasomes and may serve as a potential therapeutic strategy for HN treatment.

SGLT-2 Inhibitors and the Inflammasome: What's Next in the 21st Century?

The nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome in the kidney and the heart is increasingly being suggested to play a key role in mediating inflammation. In the kidney, NLRP3 activation was associated with the progression of diabetic kidney disease. In the heart, activation of the NLRP3 inflammasome was related to the enhanced release of interleukin-1β (IL-1β) and the subsequent induction of atherosclerosis and heart failure. Apart from their glucose-lowering effects, SGLT-2 inhibitors were documented to attenuate activation of the NLRP3, thus resulting in the constellation of an anti-inflammatory milieu. In this review, we focus on the interplay between SGLT-2 inhibitors and the inflammasome in the kidney, the heart and the neurons in the context of diabetes mellitus and its complications.

PRR-HyPred: A two-layer hybrid framework to predict pattern recognition receptors and their families by employing sequence encoded optimal features

Pattern recognition receptors (PRRs) recognize distinct features on the surface of pathogens or damaged cells and play key roles in the innate immune system. PRRs are divided into various families, including Toll-like receptors, retinoic acid-inducible gene-I-like receptors, nucleotide oligomerization domain-like receptors, and C-type lectin receptors. As these are implicated in host health and several diseases, their accurate identification is indispensable for their functional characterization and targeted therapeutic approaches. Here, we construct PRR-HyPred, a novel two-layer hybrid framework in which the first layer predicts whether a given sequence is PRR or non-PRR using a support vector machine, and in the second, the predicted PRR sequence is assigned to a specific family using a random forest-based classifier. Based on a 10-fold cross-validation test, PRR-HyPred achieved 83.4 % accuracy in the first layer and 95 % in the second, with Matthew's correlation coefficient values of 0.639 and 0.816, respectively. This is the first study that can simultaneously predict and classify PRRs into specific families. PRR-HyPred is available as a web portal at https://procarb.org/PRRHyPred/. We hope that it could be a valuable tool for the large-scale prediction and classification of PRRs and subsequently facilitate future studies.