Hydroxychloroquine attenuates renal ischemia/reperfusion injury by inhibiting cathepsin mediated NLRP3 inflammasome activation

Apelin-13 exerts protective effects against acute kidney injury by lysosomal function regulation

BACKGROUND

Recent studies suggest that the loss of lysosomal function is associated with acute kidney injury (AKI), potentially leading to impaired autophagy. Apelin has been known to regulate autophagy processes in cardiovascular and pulmonary diseases. We sought to explore its potential contribution in lysosomal function and autophagy modulation during AKI.

METHODS

Apelin-13 (30 μg/kg) or a vehicle control was administered to mice intraperitoneally 24 h prior to and at 0 h, 24 h, and 48 h following renal ischemia-reperfusion (I/R) injury or a sham procedure. Kidney and serum samples were collected for analysis 24 or 72 h postoperatively.

RESULTS

Our findings indicate that apelin-13 significantly mitigated renal damage and inhibited apoptosis post-AKI. Flow cytometry analysis revealed that apelin-13 treatment modulates the macrophages polarization within the kidney from M1 to M2 phenotype. Additionally, apelin-13 was found to reduce the expression of the (pro)renin receptor, restore lysosomal membrane permeability, augment lysosomal biogenesis, and enhance autophagic flux in the kidney following AKI.

CONCLUSIONS

Our study elucidates novel mechanisms underlying the protective effects of apelin in AKI through modulating lysosomal function and autophagy.

Mesenchymal stem cells attenuate hyperoxaluria-induced kidney injury and crystal depositions via inhibiting the activation of NLRP3 inflammasome

AIMS

Calcium oxalate (CaOx) is the predominant form of kidney stones, associated with significant morbidity and recurrence rates. Mesenchymal stem cells (MSCs) have shown promise in treating renal injury, but their impact on CaOx stone formation remains unclear.

MATERIALS AND METHODS

We established a hyperoxaluria-induced AKI model in mice through intraperitoneal injection of glyoxylate. Two types of MSCs, bone marrow-derived MSCs (BMSCs) and umbilical cord-derived mesenchymal stem cells (UMSCs), were injected through tail vein injection. Histological evaluations and blood biochemical tests were performed to assess crystal deposition and kidney function. The inflammatory response and NLRP3 inflammasome activation were assessed using immunofluorescence, immunohistochemistry, TUNEL staining, and qPCR. In vitro, macrophages were cocultured in the presence of MSCs. ELISA was used to measure IL-1β and IL-18 release. MTS assays assessed renal epithelial cell protection. Western blotting evaluated NLRP3 inflammasome activation in macrophages.

KEY FINDINGS

Both BMSCs and UMSCs significantly inhibited CaOx crystal deposition and kidney injury by inhibiting NLRP3 inflammasome activation. In vitro, both MSC types suppressed NLRP3 inflammasome activation in macrophages through the NF-κB signaling pathway, leading to decreased release of IL-1β and IL-18 and enhanced protection of renal epithelial cells. This attenuation of renal tubular cell injury is a critical factor in preventing CaOx stone formation.

SIGNIFICANCE

Our findings reveal that Both BMSCs and UMSCs effectively attenuate hyperoxaluria-induced kidney injury and crystal deposition by inhibiting NLRP3 inflammasome activation. This discovery is helpful for developing new effective therapeutic means for nephrolithiasis.

Cathepsin L Aggravates Neuroinflammation via Promoting Microglia M1 Polarization and NLRP3 Activation After Spinal Cord Injury

Neuronal inflammation and apoptosis aggravate the secondary injury after spinal cord injury (SCI). Cathepsin L (CTSL) is a lysosomal cysteine protease with effects on the regulation of inflammation, but its role in SCI remains unclear. The in vivo T10 mouse spinal cord contusion model was established. The results showed that CTSL expression was increased following SCI and then gradually decreased. Moreover, CTSL was mainly expressed in microglia. To detect the function of CTSL, after contusive injury, the mice were immediately injected with lentiviruses carrying CTSL shRNA. The results showed that CTSL depletion promoted functional recovery, accompanied by increased locomotor ability. CTSL deficiency reduced lesion cavity areas by inhibiting neuronal apoptosis and neuroinflammation. Indeed, CTSL deficiency decreased the secretion of TNF-α, IL-6, and MCP-1 and M1 microglia polarization in the spinal cord. CTSL depletion inhibited the expression and assembly of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome. In vitro, CTSL expression was increased in LPS-treated BV2 cells. CTSL silencing repressed LPS-induced M1 polarization, as evidenced by the reduction in TNF-α, IL-6, and MCP-1 expression in the supernatant of BV2 cells. CTSL knockdown induced the downregulation of NLRP3 expression and activation. The inhibition role of CTSL knockdown in microglial inflammation and M1 polarization was reversed by NLRP3 agonist. Collectively, the study suggests that CTSL induces the microglia M1 polarization-mediated inflammation via promoting NLRP3 activation and thereby inhibits functional recovery after SCI.

Precision medicine for acute kidney injury: Baicalein-nanodrug delivery system combat oxidative stress and repair mitochondrial dysfunction

Acute kidney injury (AKI) is characterized by high morbidity and mortality globally and serves as an independent risk factor for chronic kidney disease. Oxidative stress is the main pathogenic mechanism leading to acute kidney injury (AKI) and subsequent renal failure, which is characterized by excessive reactive oxygen species (ROS) and mitochondrial dysfunction. Treatment options for AKI remain supportive care, it is urgent to develop more viable therapeutic strategies. In this study, we engineered a nanodrug delivery system aiming to achieve precise treatment of AKI. The nanocarriers (Apt-NS) exhibited excellent serum stability and biocompatibility and were capable of specifically recognizing AKI renal tubular cells. Apt-NS were loaded with baicalein (BAI) to form a nanodrug delivery system (Apt-NS-BAI). In comparison to the BAI, Apt-NS-BAI demonstrated more pronounced effects in improving cell viability, scavenging ROS and anti-apoptosis. Simultaneously, in vivo animal experiments also confirmed that Apt-NS-BAI could recognize the injury site and exert biological functions of anti-apoptosis and alleviating renal damage. Overall, this study successfully constructed a nanodrug delivery system with the ability to target AKI renal tubular cells, enabling accurate and efficient delivery of baicalein to injury site and exerting protective functions against oxidative stress. This research offers novel insights into the precision treatment of AKI and contributes to the acceleration of the application of nanotechnology in kidney diseases.

Mechanism of action of the nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome and its regulation in liver injury

ABSTRACT

Nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) is a cytosolic pattern recognition receptor that recognizes multiple pathogen-associated molecular patterns and damage-associated molecular patterns. It is a cytoplasmic immune factor that responds to cellular stress signals, and it is usually activated after infection or inflammation, forming an NLRP3 inflammasome to protect the body. Aberrant NLRP3 inflammasome activation is reportedly associated with some inflammatory diseases and metabolic diseases. Recently, there have been mounting indications that NLRP3 inflammasomes play an important role in liver injuries caused by a variety of diseases, specifically hepatic ischemia/reperfusion injury, hepatitis, and liver failure. Herein, we summarize new research pertaining to NLRP3 inflammasomes in hepatic injury, hepatitis, and liver failure. The review addresses the potential mechanisms of action of the NLRP3 inflammasome, and its regulation in these liver diseases.

ESCRT III-mediated lysosomal repair improve renal tubular cell injury in cisplatin-induced AKI

The chemotherapeutic agent cisplatin is widely utilized for the treatment of various solid tumors. However, its clinical utility is limited by nephrotoxicity. Although numerous studies have demonstrated the potential of enhancing macroautophagy/autophagy in alleviating cisplatin-induced acute kidney injury (AKI), the dynamics of the autophagic process during renal tubular injury remain to be elucidated. In our investigation, we observed that cisplatin treatment leads to increased expression of LC3-II, GABARAPL1, SQSTM1/p62 and NBR1 in mouse renal tubular epithelial cells and BUMPT cells. Moreover, ultrastructurally, there is extensive accumulation of autophagic vacuoles in AKI mice. These findings imply that cisplatin-induced AKI results in impaired autophagic flow within renal tubular cells. Furthermore, LGALS3 (galectin 3) was found to be enriched in lysosomes after cisplatin treatment, revealing a close association between autophagy dysfunction and impaired lysosomal membrane integrity. Given the damaging contents of lysosomes, lysosomal membrane permeabilization must be rapidly resolved. Our findings showed that ESCRT III subunit CHMP4A-mediated lysosomal membrane repair significantly ameliorates autophagic defects and protects against lysosomal damage-induced cell death in a cisplatin-induced AKI model. In conclusion, our study indicates that ESCRT III-mediated lysosomal repair can relieve cisplatin-induced cell apoptosis and restore normal autophagy function in renal tubular epithelial cells. This mechanism plays a protective role against cisplatin-induced AKI.Abbreviations: AAV: adeno-associated virus; AKI: acute kidney injury; CQ: chloroquine; ESCRT: endosomal sorting complex required for transport; LMP: lysosomal membrane permeabilization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PAS: periodic acid Schiff; PTECs: proximal renal tubule epithelial cells; TEM: transmission electron microscopy; TUNEL: terminal deoxynucleotidyl transferase dUTP nick end labeling.

Different doses of hydroxychloroquine regulate the structure of intestinal flora and glycosyltransferase activity in rats with IgA nephropathy

BACKGROUND

Hydroxychloroquine (HCQ), by virtue of its ability to reduce proteinuria, is an alternative therapy for Immunoglobulin A nephropathy (IgAN). This study investigated the effects of different doses of HCQ on the structure of intestinal flora and glycosyltransferase activity in IgAN rats.

METHODS

IgAN model rats constructed by treatment of bovine serum albumin, castor oil and lipopolysaccharide were administered with HCQ (18 or 36 mg/kg) by gavage. Then the number of urine erythrocyte and the renal function of rats were evaluated. The levels of galactose-deficient IgA1 (Gd-IgA1), B cell activation factor (BAFF) and C-reactive protein (CRP) in serum and those of inflammatory factors in renal tissue were detected by ELISA. Renal tissue injury and IgA deposition were assessed by histological analysis. The expressions of Core 1 beta1,3-galactosyltransferase (C1GALT1), Core 1 synthase specific molecular chaperone (COSMC) and ST6 N-acetylgalactosaminide alpha-2,6-sialyltransferase 2 (ST6GALNAC2) were quantified by qRT-PCR, Western blot or in vitro enzyme assays. 16 s rDNA sequencing was used to analyze the structure of intestinal flora in rats.

RESULTS

HCQ dose-dependently decreased the levels of serum creatinine, UREA, Gd-IgA1, BAFF, CRP and urine protein, waned the number of urine erythrocyte, inhibited the expressions of inflammatory factors and IgA deposition in renal tissue, and up-regulated the expressions of C1GALT1, COSMC and down-regulated ST6GALNAC2 expression in peripheral blood mononuclear cells (PBMCs).

CONCLUSION

HCQ could reduce glomerular swelling in mesangial area and improve the imbalance of intestinal flora in IgAN rats.

Cathepsin B induces kidney diseases through different types of programmed cell death

Cathepsin B (CTSB), a key cysteine protease, plays essential roles in physiological and pathological processes. As research progresses, interest in how CTSB triggers different types of programmed cell death (PCD) to induce the onset and development of diseases is increasing. Several recent studies suggest that different types of PCD mediated by CTSB play key roles in kidney diseases. In this review, we outline the fundamental mechanisms by which CTSB triggers different types of PCD in several kidney diseases and discuss the function of CTSB in various segments of the kidney. Moreover, we explore the possibilities and prospects of using CTSB as a therapeutic target for kidney diseases.

Microglial Autophagic Dysregulation in Traumatic Brain Injury: Molecular Insights and Therapeutic Avenues

Traumatic brain injury (TBI) is a complex and multifaceted condition that can result in cognitive and behavioral impairments. One aspect of TBI that has received increasing attention in recent years is the role of microglia, the brain-resident immune cells, in the pathophysiology of the injury. Specifically, increasing evidence suggests that dysfunction in microglial autophagy, the process by which cells degrade and recycle their own damaged components, may contribute to the development and progression of TBI-related impairments. Here, we unravel the pathways by which microglia autophagic dysregulation predisposes the brain to secondary damage and neurological deficits following TBI. An overview of the role of autophagic dysregulation in perpetuation and worsening of the inflammatory response, neuroinflammation, and neuronal cell death in TBI follows. Further, we have evaluated several signaling pathways and processes that contribute to autophagy dysfunction-mediated inflammation, neurodegeneration, and poor outcome in TBI. Additionally, a discussion on the small molecule therapeutics employed to modulate these pathways and mechanisms to treat TBI have been presented. However, additional research is required to fully understand the processes behind these underlying pathways and uncover potential therapeutic targets for restoring microglial autophagic failure in TBI.

Targeting AnxA2-EGFR signaling: hydroxychloroquine as a therapeutic strategy for bleomycin-induced pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease that causes progressive failure of lung function, and its molecular mechanism remains poorly understood. However, the AnnexinA2-epidermal growth factor receptor (EGFR) signaling pathway has been identified as playing a significant role in its development. Hydroxychloroquine, a common anti-malarial drug, has been found to inhibit this pathway and slow down the progression of IPF. To better understand the role of the AnxA2-EGFR signaling pathway in pulmonary fibrosis, an in vivo study was conducted. In this study, mice were induced with pulmonary fibrosis using bleomycin, and HCQ was administered intraperitoneally the next day of bleomycin induction. The study also employed nintedanib as a positive control. After the induction, the lungs showed increased levels of fibronectin and vimentin, along with enhanced expression of AnxA2, EGFR, and Gal-3, indicating pulmonary fibrosis. Additionally, the study also found that HCQ significantly inhibited these effects and showed antifibrotic properties similar to nintedanib. Overall, these findings suggest that HCQ can attenuate bleomycin-induced pulmonary fibrosis by inhibiting the AnxA2-EGFR signaling pathway. These results are promising for developing new treatments for IPF.

Knockdown of Leucine-rich alpha-2-glycoprotein 1 alleviates renal ischemia-reperfusion injury by inhibiting NOX4-mediated apoptosis, inflammation, and oxidative stress

Renal ischemia-reperfusion (I/R) injury leads mainly to acute kidney injury. Leucine-rich alpha-2-glycoprotein 1 (LRG) is upregulated in kidney tissues of mice after renal I/R injury. However, its role in renal I/R injury has not been fully elucidated. A mouse model of renal I/R injury was constructed by unilateral renal pedicle clamping and reperfusion. Mice undergoing I/R procedures exhibited renal function impairment and increased LRG protein expression compared with mice receiving sham operations. Tail vein injection with lentivirus carrying shLRG decreased renal I/R injury-induced increase in caspase-3 activity, IL-1β and IL-18 concentrations, and ROS production. Furthermore, shRNA-mediated LRG knockdown in HK-2 cells protected against H/R-induced cell damage. LRG could upregulate the expression of NADPH oxidase 4 (NOX4). We also determined the increased NOX4 expression in kidney tissues of renal I/R-operated mice and H/R-treated HK-2 cells. NOX4 overexpression reversed the inhibitory role of LRG knockdown in HK-2 cell damage caused by H/R. Collectively, our findings demonstrate that LRG knockdown decreases the NOX4 expression, thereby alleviating renal I/R injury by inhibiting cell apoptosis, inflammation, and oxidative stress.

Shikonin Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis to Attenuate Renal Ischemia/Reperfusion Injury by Activating the Sirt1/Nrf2/HO-1 Pathway

INTRODUCTION

Shikonin is the major bioactive compound abundant in Lithospermum erythrorhizon and possesses diverse pharmacological properties. This study aimed to examine shikonin roles in experimental renal ischemia/reperfusion (I/R) injury.

METHODS

Renal tissues and blood were collected from experimental renal I/R injury models. Kidney functions, structural injuries, and cellular death were assessed. Markers of endoplasmic reticulum (ER) stress were evaluated by RT-qPCR and Western blotting. The effect of shikonin on Sirt1/Nrf2/HO-1 signaling was detected by Western blotting and immunofluorescence staining. HK-2 cells that underwent hypoxia/reoxygenation (H/R) process were used to perform CCK-8 and flow cytometry.

RESULTS

For in vivo analysis, renal dysfunctions and tissue structural damage induced by I/R were relieved by shikonin. Additionally, shikonin alleviated ER stress-induced apoptosis in I/R mice. For in vitro analysis, shikonin inhibited ER stress-stimulated apoptosis of H/R cells. Mechanistically, shikonin activated Sirt1/Nrf2/HO-1 signaling post-I/R, and inhibition of Sirt1 limited shikonin-mediated protection against ER stress-stimulated apoptosis in both animal and cellular models.

CONCLUSION

By activating Sirt1/Nrf2/HO-1 signaling, shikonin inhibits apoptosis caused by ER stress and relieves renal I/R injury.

A Hypoxia-Inflammation Cycle and Multiple Sclerosis: Mechanisms and Therapeutic Implications

Purpose of Review

Multiple sclerosis (MS) is a complex neurodegenerative disease characterized by inflammation, demyelination, and neurodegeneration. Significant hypoxia exists in brain of people with MS (pwMS), likely contributing to inflammatory, neurodegenerative, and vascular impairments. In this review, we explore the concept of a negative feedback loop between hypoxia and inflammation, discussing its potential role in disease progression based on evidence of hypoxia, and its implications for therapeutic targets.

Recent Findings

In the experimental autoimmune encephalomyelitis (EAE) model, hypoxia has been detected in gray matter (GM) using histological stains, susceptibility MRI and implanted oxygen sensitive probes. In pwMS, hypoxia has been quantified using near-infrared spectroscopy (NIRS) to measure cortical tissue oxygen saturation (StO2), as well as through blood-based biomarkers such as Glucose Transporter-1 (GLUT-1). We outline the potential for the hypoxia-inflammation cycle to drive tissue damage even in the absence of plaques. Inflammation can drive hypoxia through blood-brain barrier (BBB) disruption and edema, mitochondrial dysfunction, oxidative stress, vessel blockage and vascular abnormalities. The hypoxia can, in turn, drive more inflammation.

Summary

The hypoxia-inflammation cycle could exacerbate neuroinflammation and disease progression. We explore therapeutic approaches that target this cycle, providing information about potential treatments in MS. There are many therapeutic approaches that could block this cycle, including inhibiting hypoxia-inducible factor 1-α (HIF-1α), blocking cell adhesion or using vasodilators or oxygen, which could reduce either inflammation or hypoxia. This review highlights the potential significance of the hypoxia-inflammation pathway in MS and suggests strategies to break the cycle. Such treatments could improve quality of life or reduce rates of progression.

MicroRNA-375 modulates neutrophil chemotaxis via targeting Cathepsin B in zebrafish

Neutrophils are crucial for defense against numerous infections, and their migration and activations are tightly regulated to prevent collateral tissue damage. We previously performed a neutrophil-specific miRNA overexpression screening and identified several microRNAs, including miR-375, as potent modulators for neutrophil activity. Overexpression of miR-375 decreases neutrophil motility and migration in zebrafish and human neutrophil-like cells. We screened the genes downregulated by miR-375 in zebrafish neutrophils and identified that Cathepsin B (Ctsba) is required for neutrophil motility and chemotaxis upon tail wounding and bacterial infection. Pharmacological inhibition or neutrophil-specific knockout of ctsba significantly decreased the neutrophil chemotaxis in zebrafish and survival upon systemic bacterial infection. Notably, Ctsba knockdown in human neutrophil-like cells also resulted in reduced chemotaxis. Inhibiting integrin receptor function using RGDS rescued the neutrophil migration defects and susceptibility to systemic infection in zebrafish with either miR-375 overexpression or ctsba knockout. Our results demonstrate that miR-375 and its target Ctsba modulate neutrophil activity during tissue injury and bacterial infection in vivo, providing novel insights into neutrophil biology and the overall inflammation process.

Resveratrol Ameliorates Retinal Ischemia-Reperfusion Injury by Modulating the NLRP3 Inflammasome and Keap1/Nrf2/HO-1 Signaling Pathway

Glaucoma, as an ischemia-reperfusion (I/R) injury disease, leading irreversible blindness through the loss of retinal ganglion cells (RGCs), mediated by various pathways. Resveratrol (Res) is a polyphenolic compound that exerts protective effects against I/R injury in many tissues. This article aimed to expound the underlying mechanisms through which Res protects RGCs and reduces visual dysfunction in vivo. An experimental glaucoma model was created using 6-8-week wild-type male C57BL/6J mice. Res was injected intraperitoneally for 5 days. The mice were then grouped according to the number of days after surgery and whether Res treatment was administered. We applied the Brn3a-labeled immunofluorescence staining and flash electroretinography (ERG) to assess the survival of RGCs and visual function. The expression of components of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, the interleukin-1-beta (IL-1β), and vital indicators of kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme-oxygenase 1 (HO-1) pathway at the protein and RNA levels were detected respectively. The survival of RGCs was reduced after surgery compared to controls, whereas Res application rescued RGCs and improved visual dysfunction. In conclusion, our results discovered that Res administration showed neuroprotective effects through inhibition of the NLRP3 inflammasome pathway and activation of Keap1/Nrf2/HO-1 pathway. Thus, we further elucidated the potential of Res in glaucoma therapy.

Multiparametric MRI based assessment of kidney injury in a mouse model of ischemia reperfusion injury

Kidney diseases pose a global healthcare burden, with millions requiring renal replacement therapy. Ischemia/reperfusion injury (IRI) is a common pathology of acute kidney injury, causing hypoxia and subsequent inflammation-induced kidney damage. Accurate detection of acute kidney injury due to IRI is crucial for timely intervention. We used longitudinal, multi-parametric magnetic resonance imaging (MRI) employing arterial spin labelling (ASL), diffusion weighted imaging (DWI), and dynamic contrast enhanced (DCE)-MRI to assess IRI induced changes in both the injured and healthy contralateral kidney, in a unilateral IRI mouse model (n = 9). Multi-parametric MRI demonstrated significant differences in kidney volume (p = 0.001), blood flow (p = 0.002), filtration coefficient (p = 0.038), glomerular filtration rate (p = 0.005) and apparent diffusion coefficient (p = 0.048) between the injured kidney and contralateral kidney on day 1 post-IRI surgery. Identification of the injured kidney using principal component analysis including most of the imaging parameters demonstrated an area under the curve (AUC) of 0.97. These results point to the utility of multi-parametric MRI in early detection of IRI-induced kidney damage suggesting that the combination of various MRI parameters may be suitable for monitoring the extent of injury in this model.

Effects of hydroxychloroquine on the mucosal barrier and gut microbiota during healing of mice colitis

OBJECTIVES

The present study aimed to evaluate the impact of hydroxychloroquine (HCQ) on the mucosal barrier and gut microbiota during the healing of mice colitis.

METHODS

The body weight, colon length, colon Hematoxylin-Eosin (H&E) staining, occult blood in feces and serum inflammatory factor levels were measured to evaluate the function of HCQ on inflammatory process in colitis mice. The Alcian blue staining, immunohistochemistry, immunofluorescence and serum FITC-Dextran assay were performed to assess the intestinal mucosal permeability. And the composition and expression differences of intestinal microorganisms in feces were analyzed with 16S rDNA sequencing for exploration of HCQ impact on gut microbiota in colitis.

RESULTS

The results showed that the administration of HCQ did not significantly alter the body weight, colon length, or fecal occult blood of the mice. However, HCQ treatment did lead to recovery of the structure and morphology of the intestinal mucosa, increased expression of tight junction proteins (E-cadherin and Occludin), decreased permeability of the intestinal mucosal barrier, increased serum IL-10, and decreased level of tumor necrosis factor-alpha (TNF-α). Additionally, HCQ was found to increase the abundance of Euryarchaeota, Lactobacillus_murinus and Clostridium_fusiformis, while decreasing the abundance of Oscillibacter, uncultured_Odoribacter, Bacterioidetes and Muribaculum.

CONCLUSIONS

These findings support that HCQ plays a role in the treatment of mice colitis possibly by altering the gut microbiota.

Milk Fat Globule Membrane-Containing Protein Powder Promotes Fitness in Caenorhabditis elegans

Milk-derived peptides and milk fat globule membrane (MFGM) have gained interest as health-promoting food ingredients. However, the mechanisms by which these nutraceuticals modulate the function of biological systems often remain unclear. We utilized Caenorhabditis elegans to elucidate how MFGM-containing protein powder (MProPow), previously used in a clinical trial, affect the physiology of this model organism. Our results demonstrate that MProPow does not affect lifespan but promotes the fitness of the animals. Surprisingly, gene expression analysis revealed that MProPow decreases the expression of genes functioning on innate immunity, which also translates into reduced survival on pathogenic bacteria. One of the innate immunity-associated genes showing reduced expression upon MProPow supplementation is cpr-3, the homolog of human cathepsin B. Interestingly, knockdown of cpr-3 enhances fitness, but not in MProPow-treated animals, suggesting that MProPow contributes to fitness by downregulating the expression of this gene. In summary, this research highlights the value of C. elegans in testing the biological activity of food supplements and nutraceuticals. Furthermore, this study should encourage investigations into whether milk-derived peptides and MFGM mediate their beneficial effects through the modulation of cathepsin B expression in humans.

Unraveling the differential mechanisms of revascularization promoted by MSCs & ECFCs from adipose tissue or umbilical cord in a murine model of critical limb-threatening ischemia

BACKGROUND

Critical limb-threatening ischemia (CLTI) constitutes the most severe manifestation of peripheral artery disease, usually induced by atherosclerosis. CLTI patients suffer from high risk of amputation of the lower extremities and elevated mortality rates, while they have low options for surgical revascularization due to associated comorbidities. Alternatively, cell-based therapeutic strategies represent an effective and safe approach to promote revascularization. However, the variability seen in several factors such as cell combinations or doses applied, have limited their success in clinical trials, being necessary to reach a consensus regarding the optimal "cellular-cocktail" prior further application into the clinic. To achieve so, it is essential to understand the mechanisms by which these cells exert their regenerative properties. Herein, we have evaluated, for the first time, the regenerative and vasculogenic potential of a combination of endothelial colony forming cells (ECFCs) and mesenchymal stem cells (MSCs) isolated from adipose-tissue (AT), compared with ECFCs from umbilical cord blood (CB-ECFCs) and AT-MSCs, in a murine model of CLTI.

METHODS

Balb-c nude mice (n:32) were distributed in four different groups (n:8/group): control shams, and ischemic mice (after femoral ligation) that received 50 µl of physiological serum alone or a cellular combination of AT-MSCs with either CB-ECFCs or AT-ECFCs. Follow-up of blood flow reperfusion and ischemic symptoms was carried out for 21 days, when mice were sacrificed to evaluate vascular density formation. Moreover, the long-term molecular changes in response to CLTI and both cell combinations were analyzed in a proteomic quantitative approach.

RESULTS

AT-MSCs with either AT- or CB-ECFCs, promoted a significant recovery of blood flow in CLTI mice 21 days post-ischemia. Besides, they modulated the inflammatory and necrotic related processes, although the CB group presented the slowest ischemic progression along the assay. Moreover, many proteins involved in the repairing mechanisms promoted by cell treatments were identified.

CONCLUSIONS

The combination of AT-MSCs with AT-ECFCs or with CB-ECFCs promoted similar revascularization in CLTI mice, by restoring blood flow levels, together with the modulation of the inflammatory and necrotic processes, and reduction of muscle damage. The protein changes identified are representative of the molecular mechanisms involved in ECFCs and MSCs-induced revascularization (immune response, vascular repair, muscle regeneration, etc.).

Pioglitazone ameliorates ischemia/reperfusion-induced acute kidney injury via oxidative stress attenuation and NLRP3 inflammasome

Acute kidney injury (AKI) induced by renal ischemia/reperfusion injury (IRI) is a severe clinical condition. ROS accumulation, antioxidant pathways deficiency, and inflammation are involved in IRI. Pioglitazone (Pio) exerts anti-inflammatory and antioxidant effects. The aim of this study was to explore the protective effects of pioglitazone against IRI-induced AKI. Pathogen-free Sprague-Dawley (SD) rats were arbitrarily divided into four groups: Sham operation group Control (CON) group, CON + Pio group, I/R + Saline group, and I/R + Pio group. In addition, HK-2 cells were subjected to hypoxia and reoxygenation to develop an H/R model for investigation of the protective mechanism of Pio. Pretreatment with pioglitazone in the model rats reduced urea nitrogen and creatinine levels, histopathological scores, and cytotoxicity after IRI. Pioglitazone treatment significantly attenuated renal cell apoptosis, decreased cytotoxicity, increased Bcl-2 expression, and downregulated Bax expression. Besides, the levels of ROS and inflammatory factors, including NLRP3, ASC, pro-IL-1β, pro-caspase-1, cleaved-caspase-1, TNF-α, IL-6, and IL-1β, in I/R rats and H/R cells were normalized by the pioglitazone treatment. Pioglitazone improved IRI-induced AKI by attenuating oxidative stress and NLRP3 inflammasome activation. Therefore, pioglitazone has the potential to serve as a novel agent for renal IRI treatment and prevention.

Antiapoptotic Effects of Hydroxychloroquine on Hypoxic-Ischemic Injury in Neonatal Rat Brain: May Hydroxychloroquine Be an Adjuvant Theraphy?

OBJECTIVE

Hydroxychloroquine (HCQ) has immunomodulatory, antithrombotic, cardiovascular, antimicrobial, and antineoplastic effects. In this study, we aimed to investigate the antiapoptotic and immunomodulator effects of intraperitoneal HCQ on hypoxic-ischemic (HI) injury in newborn rats.

STUDY DESIGN

Wistar albino rats, 7 to 10 days old, were randomly divided into three groups: hypoxic-ischemic encephalopathy (HIE) group, HIE treated with HCQ group, and Sham group. Left common carotid artery ligation and hypoxia model were performed in HIE and HCQ groups. The HCQ group was treated with 80 mg/kg intraperitoneal HCQ every 24 hours for 3 days, while Sham and HIE groups were given physiological saline. After 72 hours, rats were decapitated and brain tissues were stained with hematoxylin and eosin, TUNEL, and IL-1β for histopathological grading and neuronal cell injury.

RESULTS

Neuronal apoptosis was statistically lower in all neuroanatomical areas in the HCQ group compared with the HIE group. IL-1β-stained areas were similar in both HCQ and HIE groups but significantly higher compared with the Sham group. Histopathological grading scores were found to be lower in the HCQ group on the left parietal cortex and hippocampus region.

CONCLUSION

In this study, we have shown for the first time that HCQ treatment decreased apoptosis in HI newborn rat model in both hemispheres. HCQ may be a promising adjuvant therapy in neonatal HIE.

KEY POINTS

· HCQ decreased neuronal apoptosis in the ischemic penumbra of the rat brain.. · HCQ attenuates hypoxia-ischemia-induced brain injury in neonatal rats.. · HCQ has no anti-inflammatory effect on HI injury..

FGF21 Inhibits Hypoxia/Reoxygenation-induced Renal Tubular Epithelial Cell Injury by Regulating the PPARγ/NF-κB Signaling Pathway

As a predominant trigger of acute kidney injury, renal ischemia-reperfusion injury can cause permanent renal impairment, and the effective therapies are lacking. Fibroblast growth factor 21 (FGF21) plays a critical regulatory role in a variety of biological activities. This study was conducted to explore the functional of FGF21 in renal ischemia-reperfusion injury and to discuss the hidden reaction mechanism. To simulate renal ischemia-reperfusion injury in vitro, HK2 cells were induced by hypoxia/reoxygenation (H/R). The effects of FGF21 on H/R-induced HK2 cell viability were evaluated utilizing cell counting kit-8 (CCK-8). The levels of lactate dehydrogenase (LDH) and inflammatory cytokines in H/R-induced HK2 cells were assessed by means of LDH assay and enzyme-linked immunosorbent assay (ELISA). The levels of oxidative stress markers were appraised with corresponding assay kits and western blot was applied to estimate the expressions of oxidative stress-related proteins. The apoptosis of H/R-induced HK2 cells was assessed by virtue of flow cytometry. The expressions of apoptosis- and PPARγ/NF-κB signaling pathway-related proteins were evaluated with western blot. To discuss the reaction mechanism of PPARγ/NF-κB pathway in H/R-induced HK2 cells, PPARγ inhibitor GW9662 was employed to treat cells and the above experiments were then conducted again. This study found that FGF21 treatment inhibited the inflammatory response, oxidative stress and apoptosis in H/R-induced HK2 cells. Moreover, FGF21 regulated PPARγ/NF-κB signaling pathway and GW9662 partially reversed the impacts of FGF21 on the inflammatory response, oxidative stress and apoptosis in H/R-exposed HK2 cells. Collectively, FGF21 protected against H/R-induced renal tubular epithelial cell injury by regulating the PPARγ/NF-κB signaling pathway.

miR-208a-3p regulated by circUQCRC2 suppresses ischemia/reperfusion-induced acute kidney injury by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis

ABSTRACT

Background : Acute kidney injury (AKI) is a prevalent clinical syndrome with persistent kidney dysfunction. Renal ischemia/reperfusion (I/R) injury is a major cause of AKI. miR-208a-3p overexpression attenuated myocardial I/R injury. This study aims to investigate the role and mechanism of miR-208a-3p in I/R-induced AKI. Methods : AKI models were established using hypoxia/reoxygenation (H/R)-exposed tubule epithelial cell HK-2 and I/R-induced mice. The function and mechanism of miR-208a-3p were investigated by gain- or loss-of-function methods using real-time PCR, CCK-8, flow cytometry, ELISA, western blot, hematoxylin-eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, detection of Fe 2+ , reactive oxygen species, blood urea nitrogen and creatinine, and luciferase reporter assay. Results : miR-208a-3p expression was suppressed, while the expression of CELF2 and circular RNA ubiquinol-cytochrome c reductase core protein 2 (circUQCRC2) was increased in both AKI models. miR-208a-3p upregulation or circUQCRC2 silencing increased the viability, decreased the levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), reduced apoptosis and contents of Fe 2+ and reactive oxygen species, elevated expression of GPX4 and SLC7A11, and reduced ACSL4 expression in H/R-stimulated HK-2 cells. In addition, miR-208a-3p improved kidney function by alleviating renal injury, apoptosis, inflammation, and ferroptosis in AKI mouse model. CELF2 was a target gene of miR-208a-3p, which was negatively modulated by circUQCRC2. Overexpression of CELF2 blocked the function of miR-208a-3p upregulation or circUQCRC2 silencing on H/R-treated HK-2 cells. Moreover, the effects of circUQCRC2 downregulation on H/R-injured cells were also reversed by miR-208a-3p inhibitor. Conclusions : miR-208a-3p regulated by circUQCRC2 could attenuate I/R-induced AKI by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis. This study provides potential therapeutic targets for I/R-induced AKI.

YOD1 protects against MRSA sepsis-induced DIC through Lys33-linked deubiquitination of NLRP3

Disseminated intravascular coagulation (DIC) is considered to be the most common and lethal complication of sepsis. NLR-family pyrin domain-containing-3 (NLRP3) inflammasome plays an important role in host defense against microbial pathogens, and its deregulation may cause coagulation cascade and should be strictly managed. Here, we identified the deubiquitinase YOD1, which played a vital role in regulating coagulation in a NLRP3 inflammasome-dependent manner in sepsis induced by methicillin-resistant Staphylococcus aureus (MRSA). YOD1 interacted with NLRP3 to remove K33-linked ubiquitination of NLRP3 based on its deubiquitinating enzyme activity and specifically inhibited expression of NLRP3 as well as activation of NLRP3 inflammasome. Deficiency of YOD1 expression enhanced NLRP3 inflammasome activation and coagulation both in vitro and in vivo. In addition, pharmacological inhibition of the NLRP3 effectively improved coagulation and alleviated organ injury in Yod1-/- mice infected with MRSA. Thus, our study reported that YOD1 is a key regulator of coagulation during MRSA infection, and provided YOD1 as a potential therapeutic target for the treatment of NLRP3 inflammasome-related diseases, especially MRSA sepsis-induced DIC.

Specific NOX4 Inhibition Preserves Mitochondrial Function and Dampens Kidney Dysfunction Following Ischemia-Reperfusion-Induced Kidney Injury

Background: Acute kidney injury (AKI) is a sudden episode of kidney failure which is frequently observed at intensive care units and related to high morbidity/mortality. Although AKI can have many different causes, ischemia-reperfusion (IR) injury is the main cause of AKI. Mechanistically, NADPH oxidases (NOXs) are involved in the pathophysiology contributing to oxidative stress following IR. Previous reports have indicated that knockout of NOX4 may offer protection in cardiac and brain IR, but there is currently less knowledge about how this could be exploited therapeutically and whether this could have significant protection in IR-induced AKI. Aim: To investigate the hypothesis that a novel and specific NOX4 inhibitor (GLX7013114) may have therapeutic potential on kidney and mitochondrial function in a mouse model of IR-induced AKI. Methods: Kidneys of male C57BL/6J mice were clamped for 20 min, and the NOX4 inhibitor (GLX7013114) was administered via osmotic minipump during reperfusion. Following 3 days of reperfusion, kidney function (i.e., glomerular filtration rate, GFR) was calculated from FITC-inulin clearance and mitochondrial function was assessed by high-resolution respirometry. Renal histopathological evaluations (i.e., hematoxylin-eosin) and TUNEL staining were performed for apoptotic evaluation. Results: NOX4 inhibition during reperfusion significantly improved kidney function, as evidenced by a better-maintained GFR (p < 0.05) and lower levels of blood urea nitrogen (p < 0.05) compared to untreated IR animals. Moreover, IR caused significant tubular injuries that were attenuated by simultaneous NOX4 inhibition (p < 0.01). In addition, the level of renal apoptosis was significantly reduced in IR animals with NOX4 inhibition (p < 0.05). These favorable effects of the NOX4 inhibitor were accompanied by enhanced Nrf2 Ser40 phosphorylation and conserved mitochondrial function, as evidenced by the better-preserved activity of all mitochondrial complexes. Conclusion: Specific NOX4 inhibition, at the time of reperfusion, significantly preserves mitochondrial and kidney function. These novel findings may have clinical implications for future treatments aimed at preventing AKI and related adverse events, especially in high-risk hospitalized patients.

Allogeneic bone marrow mesenchymal stem cell-derived exosomes alleviate human hypoxic AKI-on-a-Chip within a tight treatment window

BACKGROUND

Acute hypoxic proximal tubule (PT) injury and subsequent maladaptive repair present high mortality and increased risk of acute kidney injury (AKI) - chronic kidney disease (CKD) transition. Human bone marrow mesenchymal stem cell-derived exosomes (hBMMSC-Exos) as potential cell therapeutics can be translated into clinics if drawbacks on safety and efficacy are clarified. Here, we determined the real-time effective dose and treatment window of allogeneic hBMMSC-Exos, evaluated their performance on the structural and functional integrity of 3D microfluidic acute hypoxic PT injury platform.

METHODS

hBMMSC-Exos were isolated and characterized. Real-time impedance-based cell proliferation analysis (RTCA) determined the effective dose and treatment window for acute hypoxic PT injury. A 2-lane 3D gravity-driven microfluidic platform was set to mimic PT in vitro. ZO-1, acetylated α-tubulin immunolabelling, and permeability index assessed structural; cell proliferation by WST-1 measured functional integrity of PT.

RESULTS

hBMMSC-Exos induced PT proliferation with ED50 of 172,582 µg/ml at the 26th hour. Hypoxia significantly decreased ZO-1, increased permeability index, and decreased cell proliferation rate on 24-48 h in the microfluidic platform. hBMMSC-Exos reinforced polarity by a 1.72-fold increase in ZO-1, restored permeability by 20/45-fold against 20/155 kDa dextran and increased epithelial proliferation 3-fold compared to control.

CONCLUSIONS

The real-time potency assay and 3D gravity-driven microfluidic acute hypoxic PT injury platform precisely demonstrated the therapeutic performance window of allogeneic hBMMSC-Exos on ischemic AKI based on structural and functional cellular data. The novel standardized, non-invasive two-step system validates the cell-based personalized theragnostic tool in a real-time physiological microenvironment prior to safe and efficient clinical usage in nephrology.

The Application of Drugs and Nano-Therapies Targeting Immune Cells in Hypoxic Inflammation

Immune cells are pivotal in the dynamic interplay between hypoxia and inflammation. During hypoxic conditions, HIF-1α, a crucial transcription factor, facilitates the adaptation of immune cells to the hypoxic micro-environment. This adaptation includes regulating immune cell metabolism, significantly impacting inflammation development. Strategies for anti-inflammatory and hypoxic relief have been proposed, aiming to disrupt the hypoxia-inflammation nexus. Research extensively focuses on anti-inflammatory agents and materials that target immune cells. These primarily mitigate hypoxic inflammation by encouraging M2-macrophage polarization, restraining neutrophil proliferation and infiltration, and maintaining Treg/TH17 balance. Additionally, oxygen-releasing nano-materials play a significant role. By alleviating hypoxia and clearing reactive oxygen species (ROS), these nano-materials indirectly influence immune cell functions. This paper delves into the response of immune cells under hypoxic conditions and the resultant effects on inflammation. It provides a comprehensive overview of various therapies targeting specific immune cells for anti-inflammatory purposes and explores nano-materials that either carry or generate oxygen to alleviate anoxic micro-environments.

Sodium sulfite triggered hepatic apoptosis, necroptosis, and pyroptosis by inducing mitochondrial damage in mice and AML-12 cells

Sodium sulfite (SS) is a biological derivative of the air pollutant sulfur dioxide, and is often used as a food and pharmaceutical additive. Improper or excessive SS exposure in liver cell death. The phenomenon of simultaneous regulation of apoptosis, necroptosis, and pyroptosis is defined as PANoptosis. However, the specific types of programmed cell death (PCD) caused by SS and their interconnections remain unclear. In the present study, C57BL/6 mice were orally administered SS for 30 d, consecutively, to establish an in vivo mouse exposure model. AML-12 cells were treated with SS for 24 h to establish an in vitro exposure model. The results showed that SS-induced mitochondrial reactive oxygen species (mtROS) accumulation activated the BAX/Bcl-2/caspase 3 pathway to trigger apoptosis and RIPK1/RIPK3/p-MLKL to trigger necroptosis. Interestingly, ROS-activated p-MLKL perforated not the cell membrane as well as the lysosomal membrane. We determined that p-MLKL mediates lysosomal membrane permeabilization (LMP), resulting in cathepsin B (CTSB) release. Furthermore, knockdown of MLKL, a CTSB inhibitor (CA074-ME) and an NLRP3 inhibitor (MCC950) alleviated SS-induced pyroptosis. In summary, our study showed that SS induced apoptosis and necroptosis though mtROS accumulation, whereas the activation of p-MLKL mediated NLRP3-dependent pyroptosis by causing CTSB leakage through LMP. This study comprehensively explored the mechanism unerlying SS-induced PCD and provided an experimental basis for p-MLKL as a potential regulatory protein in PANoptosis.

Fluorofenidone attenuates renal fibrosis by inhibiting lysosomal cathepsin‑mediated NLRP3 inflammasome activation

Currently, no antifibrotic drug in clinical use can effectively treat renal fibrosis. Fluorofenidone (AKFPD), a novel pyridone agent, significantly reduces renal fibrosis by inhibiting the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome; however, the underlying mechanism of this inhibition is not fully understood. The present study aimed to reveal the molecular mechanism underlying the suppression of NLRP3 inflammasome activation by AKFPD. It investigated the effect of AKFPD on NLRP3 activation and lysosomal cathepsins in a unilateral ureteral obstruction (UUO) rat model, and hypoxia/reoxygenation (H/R)-treated HK-2 cells and murine peritoneal-derived macrophages (PDMs) stimulated with lipopolysaccharide (LPS) and ATP. The results confirmed that AKFPD suppressed renal interstitial fibrosis and inflammation by inhibiting NLRP3 inflammasome activation in UUO rat kidney tissues. In addition, AKFPD reduced the production of activated caspase-1 and maturation of IL-1β by suppressing NLRP3 inflammasome activation in H/R-treated HK-2 cells and murine PDMs stimulated with LPS and ATP. AKFPD also decreased the activities of cathepsins B, L and S both in vivo and in vitro. Notably, AKFPD downregulated cathepsin B expression and NLRP3 colocalization in the cytoplasm after lysosomal disruptions. Overall, the results suggested that AKFPD attenuates renal fibrosis by inhibiting lysosomal cathepsin-mediated activation of the NLRP3 inflammasome.

Toxicity assessment of perovskite nanocomposites: In vivo study

Perovskite solar cells display potential as a renewable energy source because of their high-power conversion efficiency. However, there is limited understanding regarding the potential impact of perovskite on human health and the ecosystem. In this study, two sets of male Wistar albino rats received 35 injections of perovskite composite at a dosage of 0.372 mg/kg body weight. The animals underwent thorough examinations, encompassing morphometric, hematological, biochemical, histological, and behavioral analyses. Liver, kidney, and testis biopsies were processed and examined histologically. Additionally, two groups of mice (perovskite-treated and control mice, each with n = 10) underwent three behavioral tests: the Elevated Zero Maze test, Marble Burying test, and Light-Dark Box test. Perovskite-treated rats displayed a significant increase in levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, triglycerides, cholesterol, creatinine, blood urea nitrogen, white blood cells, and platelets. However, total bilirubin levels decreased, with no significant alteration in albumin values. Furthermore, exposure to perovskite composite resulted in a slight decrease in lactate dehydrogenase and red blood cell count. Histopathological examination revealed hepatic hydropic degeneration, Kupffer cells hypertrophy and hyperplasia, and renal hydropic degeneration, while testicular tissues remained unaffected. Moreover, behavioral changes were observed in perovskite-treated mice, including depression, anxiety, and compulsive burying activity. These findings suggest that exposure to perovskite can lead to significant hematological and biochemical changes, as well as hepatorenal histopathological alterations and behavioral changes. Additionally, chronic exposure to perovskite materials may induce structural and functional alterations in vital organs.

Insights into the time-course cellular effects triggered by iron oxide nanoparticles by combining proteomics with the traditional pharmacology strategy

In recent years, a number of initially approved magnetic iron oxide nanoparticle (IONP)-based nano-medicines have been withdrawn due to the obscure nano-bio effects. Therefore, there is an urgent need to study the cellular effects triggered by IONPs on cells. In this study, we investigate the time-course cellular effects on the response of RAW 264.7 cells caused by Si-IONPs via pharmacological and mass spectrometry-based proteomics techniques. Our results revealed that Si-IONPs were internalized by clathrin-mediated endocytosis within 1 hour, and gradually degraded in endolysosomes over time, which might influence autophagy, oxidative stress, innate immune response, and inflammatory response after 12 hours. Our research provides a necessary assessment of Si-IONPs for further clinical treatment.

Role of NLRP3 Inflammasome in Stroke Pathobiology: Current Therapeutic Avenues and Future Perspective

Neuroinflammation is a key pathophysiological feature of stroke-associated brain injury. A local innate immune response triggers neuroinflammation following a stroke via activating inflammasomes. The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome has been heavily implicated in stroke pathobiology. Following a stroke, several stimuli have been suggested to trigger the assembly of the NLRP3 inflammasome. Recent studies have advanced the understanding and revealed several new players regulating NLRP3 inflammasome-mediated neuroinflammation. This article discussed recent advancements in NLRP3 assembly and highlighted stroke-induced mitochondrial dysfunction as a major checkpoint to regulating NLRP3 activation. The NLRP3 inflammasome activation leads to caspase-1-dependent maturation and release of IL-1β, IL-18, and gasdermin D. In addition, genetic or pharmacological inhibition of the NLRP3 inflammasome activation and downstream signaling has been shown to attenuate brain infarction and improve the neurological outcome in experimental models of stroke. Several drug-like small molecules targeting the NLRP3 inflammasome are in different phases of development as novel therapeutics for various inflammatory conditions, including stroke. Understanding how these molecules interfere with NLRP3 inflammasome assembly is paramount for their better optimization and/or development of newer NLRP3 inhibitors. In this review, we summarized the assembly of the NLRP3 inflammasome and discussed the recent advances in understanding the upstream regulators of NLRP3 inflammasome-mediated neuroinflammation following stroke. Additionally, we critically examined the role of the NLRP3 inflammasome-mediated signaling in stroke pathophysiology and the development of therapeutic modalities to target the NLRP3 inflammasome-related signaling for stroke treatment.

Cathepsin B aggravates atherosclerosis in ApoE-deficient mice by modulating vascular smooth muscle cell pyroptosis through NF-κB / NLRP3 signaling pathway

Atherosclerosis (AS) is a chronic inflammatory disease involving cell death and inflammatory responses. Pyroptosis, a newly discovered pro-inflammatory programmed cell death process, exacerbates inflammatory responses. However, the roles of cathepsin B (CTSB) in pyroptosis and AS remain unclear. To gain further insight, we fed ApoE-/- mice a high-fat diet to investigate the effects and mechanisms of CTSB overexpression and silencing on AS. We also explored the specific role of CTSB in vascular smooth muscle cells (VSMCs) in vitro. The study revealed that high-fat diet led to the formation of AS plaques, and CTSB was found to increase the AS plaque lesion area. Immunohistochemical and TUNEL/caspase-1 staining revealed the existence of pyroptosis in atherosclerotic plaques, particularly in VSMCs. In vitro studies, including Hoechst 33342/propidium iodide staining, a lactate dehydrogenase (LDH) release assay, detection of protein indicators of pyroptosis, and detection of interleukin-1β (IL-1β) in cell culture medium, demonstrated that oxidized low-density lipoprotein (ox-LDL) induced VSMC pyroptosis. Additionally, CTSB promoted VSMC pyroptosis. Ox-LDL increased the expression of CTSB, which in turn activated the NOD-like receptor protein 3 (NLRP3) inflammasome and promoted NLRP3 expression by facilitating nuclear factor kappa B (NF-κB) p65 nuclear translocation. This effect could be attenuated by the NF-κB inhibitor SN50. Our research found that CTSB not only promotes VSMC pyroptosis by activating the NLRP3 inflammasome, but also increases the expression of NLRP3.

Multiparametric Magnetic Resonance Investigations on Acute and Long-Term Kidney Injury

Acute kidney injury (AKI) is a frequent complication of critical illness and carries a significant risk of short- and long-term mortality. The prediction of the progression of AKI to long-term injury has been difficult for renal disease treatment. Radiologists are keen for the early detection of transition from AKI to long-term kidney injury, which would help in the preventive measures. The lack of established methods for early detection of long-term kidney injury underscores the pressing needs of advanced imaging technology that reveals microscopic tissue alterations during the progression of AKI. Fueled by recent advances in data acquisition and post-processing methods of magnetic resonance imaging (MRI), multiparametric MRI is showing great potential as a diagnostic tool for many kidney diseases. Multiparametric MRI studies offer a precious opportunity for real-time noninvasive monitoring of pathological development and progression of AKI to long-term injury. It provides insight into renal vasculature and function (arterial spin labeling, intravoxel incoherent motion), tissue oxygenation (blood oxygen level-dependent), tissue injury and fibrosis (diffusion tensor imaging, diffusion kurtosis imaging, T1 and T2 mapping, quantitative susceptibility mapping). The multiparametric MRI approach is highly promising but the longitudinal investigation on the transition of AKI to irreversible long-term impairment is largely ignored. Further optimization and implementation of renal MR methods in clinical practice will enhance our comprehension of not only AKI but chronic kidney diseases. Novel imaging biomarkers for microscopic renal tissue alterations could be discovered and benefit the preventative interventions. This review explores recent MRI applications on acute and long-term kidney injury while addressing lingering challenges, with emphasis on the potential value of the development of multiparametric MRI for renal imaging on clinical systems. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.

A variety of death modes of neutrophils and their role in the etiology of autoimmune diseases

Neutrophils are important in the context of innate immunity and actively contribute to the progression of diverse autoimmune disorders. Distinct death mechanisms of neutrophils may exhibit specific and pivotal roles in autoimmune diseases and disease pathogenesis through the orchestration of immune homeostasis, the facilitation of autoantibody production, the induction of tissue and organ damage, and the incitement of pathological alterations. In recent years, more studies have provided in-depth examination of various neutrophil death modes, revealing nuances that challenge conventional understanding and underscoring their potential clinical utility in diagnosis and treatment. This review explores the multifaceted processes and characteristics of neutrophil death, with a focus on tailored investigations within various autoimmune diseases. It also highlights the potential interplay between neutrophil death and the landscape of autoimmune disorders. The review encapsulates the pertinent pathways implicated in various neutrophil death mechanisms across diverse autoimmune diseases while also charts possible avenues for future research.

Regulation of cellular senescence by innate immunity

During the COVID-19 pandemic, the interplay between the processes of immunity and senescence is drawing more and more intensive attention. SARS-CoV-2 infection induces senescence in lung cells, failure to clear infected cells and increased presence of inflammatory factors could lead to a cytokine storm and acute respiratory disease syndrome (ARDS), which together with aging and age-associated disease lead to 70% of COVID-19-related deaths. Studies on how senescence initiates upon viral infection and how to restrict excessive accumulation of senescent cells to avoid harmful inflammation are crucially important. Senescence can induce innate immune signaling, and innate immunity can engage cell senescence. Here, we mainly review the innate immune pathways, such as cGAS-STING, TLRs, NF-κB, and NLRP3 inflammasome, participating in the senescence process. In these pathways, IFN-I and inflammatory factors play key roles. At the end of the review, we propose the strategies by which we can improve the immune function and reduce inflammation based on these findings.

Lycopene Alleviates Chronic Stress-Induced Hippocampal Microglial Pyroptosis by Inhibiting the Cathepsin B/NLRP3 Signaling Pathway

Lycopene (LYC) exerts a strong neuroprotective and antipyroptotic effects. This study explored the effects and mechanisms of LYC on chronic stress-induced hippocampal microglial damage and depression-like behaviors. The caspase-1 inhibitor VX-765 attenuated chronic restrain stress (CRS)-induced hippocampal microglial pyroptosis and depression-like behaviors. Moreover, the alleviation of CRS-induced hippocampal microglial pyroptosis and depression-like behaviors by LYC was associated with the cathepsin B/NLRP3 pathway. In vitro, the caspase-1 inhibitor Z-YVAD-FMK alleviated pyroptosis in highly aggressively proliferating immortalized (HAPI) cells. Additionally, the alleviation of corticosterone-induced HAPI cell damage and pyroptosis by LYC was associated with the cathepsin B/NLRP3 pathway. Furthermore, the cathepsin B agonist pazopanib promoted HAPI cell pyroptosis, whereas LYC inhibited pazopanib-induced pyroptosis via the cathepsin B/NLRP3 pathway. Similarly, Z-YVAD-FMK inhibited pazopanib-induced HAPI cell pyroptosis. These results suggest that LYC alleviates chronic stress-induced hippocampal microglial pyroptosis via the cathepsin B/NLRP3 pathway inhibition. This study provides a new strategy for treating chronic stress encephalopathy.

4-Octyl itaconate alleviates renal ischemia reperfusion injury by ameliorating endoplasmic reticulum stress via Nrf2 pathway

Renal ischemia-reperfusion injury (IRI) is a common clinical complication of multiple severe diseases. Owing to its high mortality and the lack of effective treatment, renal IRI is still an intractable problem for clinicians. Itaconate, which is a metabolite of cis-aconitate, can exert anti-inflammatory and antioxidant roles in many diseases. As a derivative of itaconate with high cell membrane permeability, 4-octyl itaconate (4-OI) could provide a protective effect for various diseases. However, the role of 4-OI in renal IRI is still unclear. Herein, we examined whether 4-OI afforded kidney protection through attenuating endoplasmic reticulum stress (ERS) via nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. To observe the effects of 4-OI on alleviating renal pathologic injury, improving renal dysfunction, decreasing inflammatory cytokines, and reducing oxidative stress, we utilized C57BL/6J mice with bilateral renal pedicle clamped and HK-2 cells with hypoxia/reoxygenation (H/R) exposure in our study. In addition, through western blot assay, we found 4-OI ameliorated renal IRI-induced ERS, and activated Nrf2 pathway. Moreover, Nrf2-knockout (KO) mice and Nrf2 knockdown HK-2 cells were used to validate the role of Nrf2 signaling pathway in 4-OI-mediated alleviation of ERS caused by renal IRI. We demonstrated that 4-OI relieved renal injury and suppressed ERS in wild-type mice, while the therapeutic role was not shown in Nrf2-KO mice. Similarly, 4-OI could exert cytoprotective effect and inhibit ERS in HK-2 cells after H/R, but not in Nrf2 knockdown cells. Our in vivo and in vitro studies revealed that 4-OI protected renal IRI through attenuating ERS via Nrf2 pathway.

Hydroxychloroquine in nephrology: current status and future directions

Hydroxychloroquine is one of the oldest disease-modifying anti-rheumatic drugs in clinical use. The drug interferes with lysosomal activity and antigen presentation, inhibits autophagy, and decreases transcription of pro-inflammatory cytokines. Owing to its immunomodulatory, anti-inflammatory, anti-thrombotic effect, hydroxychloroquine has been an integral part of therapy for systemic lupus erythematosus and lupus nephritis for several decades. The therapeutic versatility of hydroxychloroquine has led to repurposing it for other clinical conditions, with recent studies showing reduction in proteinuria in IgA nephropathy. Research is also underway to investigate the efficacy of hydroxychloroquine in primary membranous nephropathy, Alport's syndrome, systemic vasculitis, anti-GBM disease, acute kidney injury and for cardiovascular risk reduction in chronic kidney disease. Hydroxychloroquine is well-tolerated, inexpensive, and widely available and therefore, should its indications expand in the future, it would certainly be welcomed. However, clinicians should be aware of the risk of irreversible and progressive retinal toxicity and rarely, cardiomyopathy. Monitoring hydroxychloroquine levels in blood appears to be a promising tool to evaluate compliance, individualize the dose and reduce the risk of retinal toxicity, although this is not yet standard clinical practice. In this review, we discuss the existing knowledge regarding the mechanism of action of hydroxychloroquine, its utility in lupus nephritis and other kidney diseases, the main adverse effects and the evidence gaps that need to be addressed in future research. Created with Biorender.com. HCQ, hydroxychloroquine; GBM, glomerular basement membrane; mDC, myeloid dendritic cell; MHC, major histocompatibility complex; TLR, toll-like receptor.

Early plasma proteomic biomarkers and prediction model of acute respiratory distress syndrome after cardiopulmonary bypass: a prospective nested cohort study

BACKGROUND

Early recognition of the risk of acute respiratory distress syndrome (ARDS) after cardiopulmonary bypass (CPB) may improve clinical outcomes. The main objective of this study was to identify proteomic biomarkers and develop an early prediction model for CPB-ARDS.

METHODS

The authors conducted three prospective nested cohort studies of all consecutive patients undergoing cardiac surgery with CPB at Union Hospital of Tongji Medical College Hospital. Plasma proteomic profiling was performed in ARDS patients and matched controls (Cohort 1, April 2021-July 2021) at multiple timepoints: before CPB (T1), at the end of CPB (T2), and 24 h after CPB (T3). Then, for Cohort 2 (August 2021-July 2022), biomarker expression was measured and verified in the plasma. Furthermore, lung ischemia/reperfusion injury (LIRI) models and sham-operation were established in 50 rats to explore the tissue-level expression of biomarkers identified in the aforementioned clinical cohort. Subsequently, a machine learning-based prediction model incorporating protein and clinical predictors from Cohort 2 for CPB-ARDS was developed and internally validated. Model performance was externally validated on Cohort 3 (January 2023-March 2023).

RESULTS

A total of 709 proteins were identified, with 9, 29, and 35 altered proteins between ARDS cases and controls at T1, T2, and T3, respectively, in Cohort 1. Following quantitative verification of several predictive proteins in Cohort 2, higher levels of thioredoxin domain containing 5 (TXNDC5), cathepsin L (CTSL), and NPC intracellular cholesterol transporter 2 (NPC2) at T2 were observed in CPB-ARDS patients. A dynamic online predictive nomogram was developed based on three proteins (TXNDC5, CTSL, and NPC2) and two clinical risk factors (CPB time and massive blood transfusion), with excellent performance (precision: 83.33%, sensitivity: 93.33%, specificity: 61.16%, and F1 score: 85.05%). The mean area under the receiver operating characteristics curve (AUC) of the model after 10-fold cross-validation was 0.839 (95% CI: 0.824-0.855). Model discrimination and calibration were maintained during external validation dataset testing, with an AUC of 0.820 (95% CI: 0.685-0.955) and a Brier Score of 0.177 (95% CI: 0.147-0.206). Moreover, the considerably overexpressed TXNDC5 and CTSL proteins identified in the plasma of patients with CPB-ARDS, exhibited a significant upregulation in the lung tissue of LIRI rats.

CONCLUSIONS

This study identified several novel predictive biomarkers, developed and validated a practical prediction tool using biomarker and clinical factor combinations for individual prediction of CPB-ARDS risk. Assessing the plasma TXNDC5, CTSL, and NPC2 levels might identify patients who warrant closer follow-up and intensified therapy for ARDS prevention following major surgery.

CCN2 Activates RIPK3, NLRP3 Inflammasome, and NRF2/Oxidative Pathways Linked to Kidney Inflammation

Inflammation is a key characteristic of both acute and chronic kidney diseases. Preclinical data suggest the involvement of the NLRP3/Inflammasome, receptor-interacting protein kinase-3 (RIPK3), and NRF2/oxidative pathways in the regulation of kidney inflammation. Cellular communication network factor 2 (CCN2, also called CTGF in the past) is an established fibrotic biomarker and a well-known mediator of kidney damage. CCN2 was shown to be involved in kidney damage through the regulation of proinflammatory and profibrotic responses. However, to date, the potential role of the NLRP3/RIPK3/NRF2 pathways in CCN2 actions has not been evaluated. In experimental acute kidney injury induced with folic acid in mice, CCN2 deficiency diminished renal inflammatory cell infiltration (monocytes/macrophages and T lymphocytes) as well as the upregulation of proinflammatory genes and the activation of NLRP3/Inflammasome-related components and specific cytokine products, such as IL-1β. Moreover, the NRF2/oxidative pathway was deregulated. Systemic administration of CCN2 to C57BL/6 mice induced kidney immune cell infiltration and activated the NLRP3 pathway. RIPK3 deficiency diminished the CCN2-induced renal upregulation of proinflammatory mediators and prevented NLRP3 modulation. These data suggest that CCN2 plays a fundamental role in sterile inflammation and acute kidney injury by modulating the RIKP3/NLRP3/NRF2 inflammatory pathways.

GADD45A and GADD45B as Novel Biomarkers Associated with Chromatin Regulators in Renal Ischemia-Reperfusion Injury

Chromatin regulators (CRs) are essential upstream regulatory factors of epigenetic modification. The role of CRs in the pathogenesis of renal ischemia-reperfusion injury (IRI) remains unclear. We analyzed a bioinformatic analysis on the differentially expressed chromatin regulator genes in renal IRI patients using data from public domains. The hub CRs identified were used to develop a risk prediction model for renal IRI, and their expressions were also validated using Western blot, qRT-PCR, and immunohistochemistry in a murine renal IRI model. We also examined the relationships between hub CRs and infiltrating immune cells in renal IRI and used network analysis to explore drugs that target hub CRs and their relevant downstream microRNAs. The results of machine learning methods showed that five genes (DUSP1, GADD45A, GADD45B, GADD45G, HSPA1A) were upregulated in renal IRI, with key roles in the cell cycle, p38 MAPK signaling pathway, p53 signaling pathway, FoxO signaling pathway, and NF-κB signaling pathway. Two genes from the network, GADD45A and GADD45B (growth arrest and DNA damage-inducible protein 45 alpha and beta), were chosen for the renal IRI risk prediction model. They all showed good performance in the testing and validation cohorts. Mice with renal IRI showed significantly upregulated GADD45A and GADD45B expression within kidneys compared to sham-operated mice. GADD45A and GADD45B showed correlations with plasmacytoid dendritic cells (pDCs) in infiltrating immune cell analysis and enrichment in the MAPK pathway based on the weighted gene co-expression network analysis (WGCNA) method. Candidate drugs that target GADD45A and GADD45B include beta-escin, sertraline, primaquine, pimozide, and azacyclonol. The dysregulation of GADD45A and GADD45B is related to renal IRI and the infiltration of pDCs, and drugs that target GADD45A and GADD45B may have therapeutic potential for renal IRI.

Combined exposure to benzo(a)pyrene and dibutyl phthalate aggravates pro-inflammatory macrophage polarization in spleen via pyroptosis involving cathepsin B

Humans are often simultaneously exposed to benzo(a)pyrene (BaP) and dibutyl phthalate (DBP) through consumption of food and water. Yet, direct evidence of the link between BaP and DBP co-exposure and the risk of splenic injury is lacking. In the present study, we established the rats and primary splenic macrophages models to evaluate the effects of BaP or/and DBP exposure on spleen and underlying mechanisms. Compared to the single exposure or control groups, the co-exposure group showed more severe spleen damage and higher production of pro-inflammatory cytokines. Co-exposure to BaP and DBP resulted in a 1.79-fold, 2.11-fold and 1.9-fold increase in the M1 macrophage markers iNOS, NLRP3 (pyroptosis marker protein) and cathepsin B (CTSB), respectively, and a 0.8-fold decrease in the M2 macrophage marker Arg1 in vivo. The more prominent effects in perturbation of imbalance in M1/M2 polarization (iNOS, 2.25-fold; Arg1, 0.55-fold), pyroptosis (NLRP3, 1.43-fold), and excess CTSB (1.07-fold) in macrophages caused by BaP and DBP co-exposure in vitro were also found. Notably, MCC950 (the NLRP3-specific inhibitor) treatment attenuated the pro-inflammatory macrophage polarization and following pro-inflammatory cytokine production triggered by BaP and DBP co-exposure. Furthermore, CA-074Me (the CTSB-specific inhibitor) suppressed the macrophages pyroptosis, pro-inflammatory macrophage polarization, and secretion of pro-inflammatory cytokine induced by BaP and DBP co-exposure. In conclusion, this study indicates co-exposure to BaP and DBP poses a higher risk of spleen injury. Pro-inflammatory macrophage polarization regulated by pyroptosis involving CTSB underlies the spleen injury caused by BaP and DBP co-exposure.

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.

Trimethylamine N-Oxide (TMAO) Inducing Endothelial Injury: UPLC-MS/MS-Based Quantification and the Activation of Cathepsin B-Mediated NLRP3 Inflammasome

TMAO is a new risk biomarker for cardiovascular disease. With trimethylammonium as its main chemical skeleton, TMAO is structurally similar to many endogenous metabolites, such as acetylcholine, carnitine, phosphorylcholine, etc. The mechanism of TMAO on the pathological process of CVD is still unclear. In this study, the quantitative analysis of plasma TMAO is conducted, and the contribution of Cathepsin B and NLRP3 inflammasome during the process of TMAO-induced endothelial injury was proposed and investigated at animal and cellular levels. Immunofluorescence assay was applied to represent the protein expression of Cathepsin B and NLRP3 inflammasome located at endothelial cells. The results showed that TMAO could disrupt endothelial cells permeability to induce endothelial injury, meanwhile, TMAO could increase NLRP3 inflammasome activation and promote the activity and expression of Cathepsin B in vitro and in vivo, whereas inhibition of NLRP3 inflammasome activation by MCC950 could protect the endothelial cells from TMAO associated endothelial injury via Cathepsin B. The study reveals that TMAO can cause endothelial injury via Cathepsin B-dependent NLRP3 inflammasome, and inhibition of Cathepsin B and NLRP3 inflammasome can reduce the TMAO-induced damage. The results provide new insight into the role of TMAO in CVD, which can be a potential therapeutic target for disease treatment and drug design.

Mechanistic Insights into the Role of OPN in Mediating Brain Damage via Triggering Lysosomal Damage in Microglia/Macrophage

We previously found that osteopontin (OPN) played a role in hypoxia–ischemia (HI) brain damage. However, its underlying mechanism is still unknown. Bioinformatics analysis revealed that the OPN protein was linked to the lysosomal cathepsin B (CTSB) and galectin-3 (GAL-3) proteins after HI exposure. In the present study, we tested the hypothesis that OPN was able to play a critical role in the lysosomal damage of microglia/macrophages following HI insult in neonatal mice. The results showed that OPN expression was enhanced, especially in microglia/macrophages, and colocalized with lysosomal-associated membrane protein 1 (LAMP1) and GAL-3; this was accompanied by increased LAMP1 and GAL-3 expression, CTSB leakage, as well as impairment of autophagic flux in the early stage of the HI process. In addition, the knockdown of OPN expression markedly restored lysosomal function with significant improvements in the autophagic flux after HI insult. Interestingly, cleavage of OPN was observed in the ipsilateral cortex following HI. The wild-type OPN and C-terminal OPN (Leu152-Asn294), rather than N-terminal OPN (Met1-Gly151), interacted with GAL-3 to induce lysosomal damage. Furthermore, the secreted OPN stimulated lysosomal damage by binding to CD44 in microglia in vitro. Collectively, this study demonstrated that upregulated OPN in microglia/macrophages and its cleavage product was able to interact with GAL-3, and secreted OPN combined with CD44, leading to lysosomal damage and exacerbating autophagosome accumulation after HI exposure.

Treating diabetes with combination of phosphodiesterase 5 inhibitors and hydroxychloroquine-a possible prevention strategy for COVID-19?

Type 2 diabetes (T2D) is one of the major risk factors for developing cardiovascular disease and the resultant devastating morbidity and mortality. The key features of T2D are hyperglycemia, hyperlipidemia, insulin resistance, and impaired insulin secretion. Patients with diabetes and myocardial infarction have worse prognosis than those without T2D. Moreover, obesity and T2D are recognized risk factors in developing severe form of COVID-19 with higher mortality rate. The current lines of drug therapy are insufficient to control T2D and its serious cardiovascular complications. Phosphodiesterase 5 (PDE5) is a cGMP specific enzyme, which is the target of erectile dysfunction drugs including sildenafil, vardenafil, and tadalafil. Cardioprotective effects of PDE5 inhibitors against ischemia/reperfusion (I/R) injury were reported in normal and diabetic animals. Hydroxychloroquine (HCQ) is a widely used antimalarial and anti-inflammatory drug and its hyperglycemia-controlling effect in diabetic patients is also under investigation. This review provides our perspective of a potential use of combination therapy of PDE5 inhibitor with HCQ to reduce cardiovascular risk factors and myocardial I/R injury in T2D. We previously observed that diabetic mice treated with tadalafil and HCQ had significantly reduced fasting blood glucose and lipid levels, increased plasma insulin and insulin-like growth factor-1 levels, and improved insulin sensitivity, along with smaller myocardial infarct size following I/R. The combination treatment activated Akt/mTOR cellular survival pathway, which was likely responsible for the salutary effects. Therefore, pretreatment with PDE5 inhibitor and HCQ may be a potentially useful therapy not only for controlling T2D but also reducing the rate and severity of COVID-19 infection in the vulnerable population of diabetics.

PRETREATMENT WITH ERYTHROPOIETIN ALLEVIATES THE RENAL DAMAGE INDUCED BY ISCHEMIA REPERFUSION VIA REPRESSION OF INFLAMMATORY RESPONSE

OBJECTIVE

The aim: This study aimed to examine the anti-inflammatory, and antiapoptotic effects of erythropoietin against kidney injury inducted by ischemia reperfusion in experimental model.

PATIENTS AND METHODS

Materials and methods: 20 male Sprague Dawley rats were randomly divided into 4 equal groups: sham (subject to median laparotomy only), control (subject to 30 minutes ischemia and 2hours reperfusion), vehicle (injected by distilled water and subjected to the same procedure of ischemia reperfusion), erythropoietin group (as in vehicle group but the rats pretreated with 1000 U/kg of erythropoietin). The left kidney and blood specimen were collected. The blood utilized to assess serum creatinine. While kidneys utilized to assessed MCP-1, TLR2, and caspase-3 in addition to histopathological evaluation.

RESULTS

Results: Control and vehicle samples showed that a significant elevation in serum creatinine, TLR2, caspase-3, and MCP-1 as compared with sham group. The histological eval¬uation showed a significant rise in kidney injury scores. Kidneys and blood samples of erythropoietin pretreated rats established histopathological and functional improvement as evidenced via reduced kidney injury scores in addition to the reduction in serum creatinine, as well as there were a significant diminished in caspase-3, MCP-1, and TLR2 levels when compared with control and vehicle groups.

CONCLUSION

Conclusions: Erythropoietin has renoprotective effect against ischemia and reperfusion, which achieved by decrease the inflammatory response as well as antiapoptotic effect.

The role of NLRP3 inflammasome in sepsis: A potential therapeutic target

Sepsis is the host immune imbalance following infection and leads to organ dysfunction, with highly complicated pathophysiology. To date, sepsis still lacks effective therapies with high mortality rates. Recently, numerous studies have highlighted the potential of NLRP3 inflammasome as a therapeutic target during sepsis. NLRP3 inflammasome is a protein complex that could induce the activation of caspase-1 and the following release of pro-inflammatory cytokines such as IL-1β and IL-18. It was demonstrated that NLRP3 inflammasome was involved in the development and progression of sepsis. In contrast, inhibition of NLRP3 inflammasome activation could mitigate the inflammatory response, protect organ function, and improve outcomes and mortality. This paper illustrated the activation pathways of the NLRP3 inflammasome and its possible molecular mechanisms in the pathophysiology of sepsis. Meanwhile, the beneficial effects of inhibiting NLRP3 activation in sepsis-related organ damage were also presented. In addition, the diverse role of NLRP3 inflammasome in bacterial clearance was addressed. Of note, several herbal extracts targeting NLRP3 inflammasome in the treatment of sepsis were emphasized. We hope that this paper could provide a basis for further drug research targeting NLRP3 inflammasome.

CTSB promotes sepsis-induced acute kidney injury through activating mitochondrial apoptosis pathway

Background

Acute kidney injury is a common and severe complication of sepsis. Sepsis -induced acute kidney injury(S-AKI) is an independent risk factor for mortality among sepsis patients. However, the mechanisms of S-AKI are complex and poorly understand. Therefore, exploring the underlying mechanisms of S-AKI may lead to the development of therapeutic targets.

Method

A model of S-AKI was established in male C57BL/6 mice using cecal ligation and puncture (CLP). The data-independent acquisition (DIA)-mass spectrometry-based proteomics was used to explore the protein expression changes and analyze the key proteomics profile in control and CLP group. The methodology was also used to identify the key proteins and pathways. S-AKI in vitro was established by treating the HK-2 cells with lipopolysaccharide (LPS). Subsequently, the effect and mechanism of Cathepsin B (CTSB) in inducing apoptosis in HK-2 cells were observed and verified.

Results

The renal injury scores, serum creatinine, blood urea nitrogen, and kidney injury molecule 1 were higher in septic mice than in non-septic mice. The proteomic analysis identified a total of 449 differentially expressed proteins (DEPs). GO and KEGG analysis showed that DEPs were mostly enriched in lysosomal-related cell structures and pathways. CTSB and MAPK were identified as key proteins in S-AKI. Electron microscopy observed enlarged lysosomes, swelled and ruptured mitochondria, and cytoplasmic vacuolization in CLP group. TUNEL staining and CTSB activity test showed that the apoptosis and CTSB activity were higher in CLP group than in control group. In HK-2 cell injury model, the CTSB activity and mRNA expression were increased in LPS-treated cells. Acridine orange staining showed that LPS caused lysosomal membrane permeabilization (LMP). CA074 as an inhibitor of CTSB could effectively inhibit CTSB activity. CCK8 and Annexin V/PI staining results indicated that CA074 reversed LPS-induced apoptosis of HK-2 cells. The JC-1 and western blot results showed that LPS inhibited mitochondrial membrane potential and activated mitochondrial apoptosis pathway, which could be reversed by CA074.

Conclusions

LMP and CTSB contribute to pathogenesis of S-AKI. LPS treatment induced HK-2 cell injury by activating mitochondrial apoptosis pathway. Inhibition of CTSB might be a new therapeutic strategy to alleviate sepsis-induced acute kidney injury.