miR-22 alleviates sepsis-induced acute kidney injury via targeting the HMGB1/TLR4/NF-κB signaling pathway

Afobazole alleviates streptozotocin-induced diabetic nephropathy in rats via hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties: Role of the S1R/Nrf2 antioxidant axis

AIMS

Sigma-1 receptor (S1R) activation was recently identified as a promising target for preventing diabetic nephropathy (DN) by mitigating hypoxia, oxidative stress, and inflammation. This study aimed to investigate the potential reno-protective effect of the S1R agonist afobazole against streptozotocin (STZ)-induced DN in rats compared to metformin.

MATERIALS AND METHODS

Rats were split into six groups: the normal control group; the diabetic control group received STZ (55 mg/kg i.p.); the other four groups received STZ and were treated with different doses of either afobazole (10, 15, and 20 mg/kg) or metformin (200 mg/kg). Metabolic parameters and renal function were assessed. Expression levels of oxidative stress markers and inflammatory cytokines were measured using ELISA, apoptosis-related proteins were evaluated using immunohistochemistry, and gene expression of S1R, Nrf2, NF-κB, and TLR-4 was determined. Histopathological analysis was performed on kidney tissues.

KEY FINDINGS

Both afobazole and metformin exerted hypoglycemic effects, alleviating renal injury, reducing blood urea nitrogen (BUN) and serum creatinine, and restoring oxidant/antioxidant balance in diabetic rats. Both treatments boosted renal S1R and Nrf2 levels, suppressed inflammatory proteins and cytokines, and reduced apoptotic features.

SIGNIFICANCE

The study revealed that afobazole provided nephroprotection in STZ-induced DN through a hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic potential mediated by activating the S1R/Nrf2 antioxidant axis. The 15 mg/kg dose elicited the most pronounced nephroprotective effects, outperforming other treatment groups.

Clemastine mitigates sepsis-induced acute kidney injury in rats; the role of α-Klotho/TLR-4/MYD-88/NF-κB/ Caspase-3/ p-P38 MAPK signaling pathways

Sepsis is a fatal condition, with an annual incidence of more than 48 million cases as well as 11 million deaths resulting from it. Moreover, sepsis continues to rank as the fifth most prevalent cause of mortality globally. The objective of this study is to investigate if Clemastine (CLM) pretreatment protects against acute kidney injury (AKI) caused by cecal ligation and puncture (CLP) via modulating Toll-like receptor-4 (TLR-4), Myeloid differentiation primary response 88 (MYD-88), nuclear factor kappa B (NF-κB), Bcl-2-associated X (Bax), B-cell lymphoma-2 (Bcl-2), and caspase-3 signaling pathways. CLM markedly attenuated sepsis-caused molecular, biochemical, and histopathological alterations. CLM downregulated the levels of the proinflammatory markers, suppressed the expression of cleaved caspase-3, TLR-4 and MYD-88 as well as inactivating NF-κB p-P65 and p-P38 proteins, inhibited Bax, NF-κB, and caspase-3 genes expression, and augmented α-Klotho protein expression as well as Bcl-2 gene expression. Finally, CLM pretreatment protected against acute kidney injury by preventing TLR-4/p-P38 pathway-mediated apoptotic cell death in rats.

The interplay of TapSAKI and NEAT-1 as potential modulators in gentamicin-induced acute kidney injury via orchestrating miR-22-3p/TLR4/MyD88/NF-қB/IL-1 β milieu: Novel therapeutic approach of Betanin

INTRODUCTION

Gentamicin (GNT) is a broad-spectrum antibiotic that is widely prescribed in critically ill patients. However, GNT exerts deleterious effects on renal proximal tubules which could predispose to acute kidney injury (AKI).

AIM

The study aimed to investigate the interplay of TapSAKI, NEAT-1, and miR-22-3p in GNT-induced AKI via modulating the TLR4/MyD88/NF-қB/IL-1β trajectory. The study was extended to show the role of betanin (BET) in alleviating GNT-induced AKI.

METHODS

BET (25  mg/kg/day) was administered via oral route for 28 consecutive days in addition to GNT (100  mg/kg/day) i.p. during the last 8 days. TapSAKI, NEAT-1, and miR-22-3p gene expressions were measured using RT-PCR. The levels of SCr, urea were measured using colorimetric assay, whereas KIM-1, TLR4, and IL-1β were measured using ELISA technique. Additionally, histopathological examinations were done.

RESULTS

The present study revealed that the expression of TapSAKI and NEAT-1 were significantly upregulated in GNT-induced AKI group, whereas miR-22-3p was significantly downregulated. There were significant associations between the expression of these non-coding RNAs and TLR4/NF-қB/MyD88/IL-1β axis as well as malondialdehyde and glutathione levels. Favorably, BET pretreated group normalized the levels of SCr, urea, and KIM-1 and showed a significant downregulation of TapSAKI and NEAT-1 and upregulation of miR-22-3p compared with GNT-induced AKI group. Furthermore, BET showed a marked inhibition of TLR4/MyD88/NF-қB/IL-1β cascade compared with non-treated AKI rats. Moreover, BET normalized oxidative stress markers.

CONCLUSION

BET reduced GNT's toxic effects on kidneys through modulating TLR4/MyD88/NF-қB/IL-1β signaling pathway under the influence of lncRNAs TapSAKI, NEAT-1, and miRNA-22-3p, which consequently suppress oxidative stress and inflammation.

miR-16-5p aggravates sepsis-associated acute kidney injury by inducing apoptosis

Sepsis-associated acute kidney injury (S-AKI) is a common disease in pediatric intensive care units (ICU) with high morbidity and mortality. The newly discovered results indicate that microRNAs (miRNAs) play an important role in the diagnosis and treatment of S-AKI and can be used as markers for early diagnosis. In this study, the expression level of miR-16-5p was found to be significantly upregulated about 20-fold in S-AKI patients, and it also increased by 1.9 times in the renal tissue of S-AKI mice. Receiver operating characteristic (ROC) curve analysis showed that miR-16-5p had the highest predictive accuracy in the diagnosis of S-AKI (AUC = 0.9188). In vitro, the expression level of miR-16-5p in HK-2 cells treated with 10 μg/mL lipopolysaccharide (LPS) increased by more than 2 times. In addition, LPS-exposed renal tissue and HK-2 cells lead to upregulation of inflammatory cytokines IL-6, IL-1β, TNF-a, and kidney damage molecules kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL). However, inhibition of miR-16-5p significantly mitigated LPS expose-mediated kidney injury and inflammation. Furthermore, LPS-exposed HK-2 cells increased more than 1.7-fold the expression levels of Bax and caspase-3, decreased 3.2-fold the expression level of B-cell lymphoma-2 (Bcl-2), and significantly promoted the occurrence of apoptosis. MiR-16-5p mimic further increased LPS-induced apoptosis in HK-2 cells. Nevertheless, inhibition of miR-16-5p significantly attenuated this effect. In summary, up-regulation of miR-16-5p expression can significantly aggravate renal injury and apoptosis in S-AKI, which also proves that miR-16-5p can be used as a potential biomarker to promote early identification of S-AKI.

Usp9x contributes to the development of sepsis-induced acute kidney injury by promoting inflammation and apoptosis in renal tubular epithelial cells via activation of the TLR4/nf-κb pathway

As a pattern recognition receptor, Toll-like receptor 4 (TLR4) is crucial for the development and progression of acute kidney injury (AKI). This study aims to explore whether the deubiquitinase Usp9x influences the TLR4/NF-B pathway to cause sepsis-induced acute kidney injury (S-AKI). The model of AKI was established in Sprague-Dawley rats using the cecal ligation and puncture (CLP) method, while renal tubular epithelial cell NRK-52E was stimulated with lipopolysaccharide (LPS) in vitro. All plasmids were transfected into NRK-52E cells according to the indicated group. The deubiquitinase of TLR4 was predicted by the online prediction software Ubibrowser. Subsequently, Western blot and Pearson correlation analysis identified Usp9x protein as a potential candidate. Co-IP analysis verified the interaction between TLR4 and Usp9x. Further research revealed that overexpression of Usp9x inhibited degradation of TLR4 protein by downregulating its ubiquitination modification levels. Both in vivo and in vitro experiments observed that interference with Usp9x effectively alleviated the inflammatory response and apoptosis of renal tubular epithelial cells (RTECs) induced by CLP or LPS, whereas overexpression of TLR4 reversed this situation. Transfection with sh-Usp9x in NRK-52E cells suppressed the expression of proteins associated with the TLR4/NF-κB pathway induced by LPS. Moreover, the overexpression of TLR4 reversed the effect of sh-Usp9x transfection. Therefore, the deubiquitinase Usp9x interacts with TLR4, leading to the upregulation of its expression through deubiquitination modification, and the activation of the TLR4/NF-κB signaling pathway, thereby promoting inflammation and apoptosis in renal tubular epithelial cells and contributing to sepsis-induced acute kidney injury.

Clinical significance of miR-625-5p in patients with sepsis-induced acute kidney injury based on bioinformatics analysis

PURPOSE

Sepsis often leads to a cluster of life-threatening symptoms affecting multiple organ systems. Among the organs most vulnerable to damage in this state is the kidney; those afflicted with severe sepsis frequently encounter acute kidney injury (AKI). The study was to investigate the diagnostic role of miR-625-5p in sepsis and sepsis-induced acute kidney injury (SI-AKI) and predict the possible pathways of miR-625-5p involved in SI-AKI by bioinformatics method.

METHODS

RT-qPCR was used to detect the level of miR-625-5p, and the diagnostic value of miR-625-5p was analyzed using ROC curve. The proliferation and the concentration of inflammatory factors of HK-2 cells induced by LPS were detected by CCK-8 and ELISA. The pathway of miR-625-5p involved in SI-AKI was analyzed by bioinformatics method.

RESULTS

The miR-625-5p expression was downregulated in sepsis as well as SI-AKI and has predictive value for sepsis as well as SI-AKI. In addition, miR-625-5p promoted LPS-induced cell proliferation and inhibited the levels of inflammatory cytokines.

CONCLUSION

miR-625-5p may be a diagnostic biomarker for SI-AKI.

The Role of MicroRNA in the Pathogenesis of Acute Kidney Injury

Acute kidney injury (AKI) describes a condition associated with elevated serum creatinine levels and decreased glomerular filtration rate. AKI can develop as a result of sepsis, the nephrotoxic properties of several drugs, and ischemia/reperfusion injury. Renal damage can be associated with metabolic acidosis, fluid overload, and ionic disorders. As the molecular background of the pathogenesis of AKI is insufficiently understood, more studies are needed to identify the key signaling pathways and molecules involved in the progression of AKI. Consequently, future treatment methods may be able to restore organ function more rapidly and prevent progression to chronic kidney disease. MicroRNAs (miRNAs) are small molecules that belong to the non-coding RNA family. Recently, numerous studies have demonstrated the altered expression profile of miRNAs in various diseases, including inflammatory and neoplastic conditions. As miRNAs are major regulators of gene expression, their dysregulation is associated with impaired homeostasis and cellular behavior. The aim of this article is to discuss current evidence on the involvement of miRNAs in the pathogenesis of AKI.

PTEN in kidney diseases: a potential therapeutic target in preventing AKI-to-CKD transition

Renal fibrosis, a critical factor in the development of chronic kidney disease (CKD), is predominantly initiated by acute kidney injury (AKI) and subsequent maladaptive repair resulting from pharmacological or pathological stimuli. Phosphatase and tensin homolog (PTEN), also known as phosphatase and tensin-associated phosphatase, plays a pivotal role in regulating the physiological behavior of renal tubular epithelial cells, glomeruli, and renal interstitial cells, thereby preserving the homeostasis of renal structure and function. It significantly impacts cell proliferation, apoptosis, fibrosis, and mitochondrial energy metabolism during AKI-to-CKD transition. Despite gradual elucidation of PTEN's involvement in various kidney injuries, its specific role in AKI and maladaptive repair after injury remains unclear. This review endeavors to delineate the multifaceted role of PTEN in renal pathology during AKI and CKD progression along with its underlying mechanisms, emphasizing its influence on oxidative stress, autophagy, non-coding RNA-mediated recruitment and activation of immune cells as well as renal fibrosis. Furthermore, we summarize prospective therapeutic targeting strategies for AKI and CKD-treatment related diseases through modulation of PTEN.

High-mobility group box 1 and its related receptors: potential therapeutic targets for contrast-induced acute kidney injury

Percutaneous coronary intervention (PCI) is a crucial diagnostic and therapeutic approach for coronary heart disease. Contrast agents' exposure during PCI is associated with a risk of contrast-induced acute kidney injury (CI-AKI). CI-AKI is characterized by a sudden decline in renal function occurring as a result of exposure to intravascular contrast agents, which is associated with an increased risk of poor prognosis. The pathophysiological mechanisms underlying CI-AKI involve renal medullary hypoxia, direct cytotoxic effects, endoplasmic reticulum stress, inflammation, oxidative stress, and apoptosis. To date, there is no effective therapy for CI-AKI. High-mobility group box 1 (HMGB1), as a damage-associated molecular pattern molecule, is released extracellularly by damaged cells or activated immune cells and binds to related receptors, including toll-like receptors and receptor for advanced glycation end product. In renal injury, HMGB1 is expressed in renal tubular epithelial cells, macrophages, endothelial cells, and glomerular cells, involved in the pathogenesis of various kidney diseases by activating its receptors. Therefore, this review provides a theoretical basis for HMGB1 as a therapeutic intervention target for CI-AKI.

Knockdown of circ-Gatad1 alleviates LPS induced HK2 cell injury via targeting miR-22-3p/TRPM7 axis in septic acute kidney

BACKGROUND

Sepsis is a life-threatening, systemic inflammatory disease that can lead to a variety of conditions, including septic acute kidney injury (AKI). Recently, multiple circular Rnas (circRNAs) have been implicated in the development of this disease.

METHODS

In this study, we aimed to elucidate the role of circ-Gatad1 in sepsis induced AKI and its potential mechanism of action. High-throughput sequencing was used to investigate abnormal expression of circRNA in AKI and healthy volunteer. Bioinformatics analysis and luciferase reporting analysis were used to clarify the interacted relationship among circRNA, miRNA and mRNA. HK2 cells were treated with lipopolysaccharide (LPS) to establish septic AKI cell model. HK2 cells were employ to analysis the ROS, inflammatory cytokines expression, proliferation and apoptosis under LPS condition.

RESULTS

The result show that the expression of circ-Gatad1 was increased in septic acute kidney patients. Downregulation circ-Gatad1 suppressed LPS-treated induced HK2 cells injury including apoptosis, proliferation ability, ROS and inflammatory cytokines level. Bioinformatics and luciferase report analysis confirmed that both miR-22-3p and TRPM7 were downstream targets of circ-Gatad1. Overexpression of TRPM7 or downregulation of miR-22-3p reversed the protective effect of si-circ-Gatad1 to HK2 after exposure to LPS (5 µg/ml) microenvironment.

CONCLUSION

In conclusion, knockdown of circ-Gatad1 alleviates LPS induced HK2 cell injury via targeting miR-22-3p/TRPM7 axis in septic acute kidney.

Perioperative acute kidney injury: The renoprotective effect and mechanism of dexmedetomidine

Dexmedetomidine (DEX) is a highly selective and potent α2-adrenoceptor (α2-AR) agonist that is widely used as a clinical anesthetic to induce anxiolytic, sedative, and analgesic effects. In recent years, a growing body of evidence has demonstrated that DEX protects against acute kidney injury (AKI) caused by sepsis, drugs, surgery, and ischemia-reperfusion (I/R) in organs or tissues, indicating its potential role in the prevention and treatment of AKI. In this review, we summarized the evidence of the renoprotective effects of DEX on different models of AKI and explored the mechanism. We found that the renoprotective effects of DEX mainly involved antisympathetic effects, reducing inflammatory reactions and oxidative stress, reducing apoptosis, increasing autophagy, reducing ferroptosis, protecting renal tubular epithelial cells (RTECs), and inhibiting renal fibrosis. Thus, the use of DEX is a promising strategy for the management and treatment of perioperative AKI. The aim of this review is to further clarify the renoprotective mechanism of DEX to provide a theoretical basis for its use in basic research in various AKI models, clinical management, and the treatment of perioperative AKI.

MicroRNAs as Biomarkers and Therapeutic Targets for Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome where a rapid decrease in kidney function and/or urine output is observed, which may result in the imbalance of water, electrolytes and acid base. It is associated with poor prognosis and prolonged hospitalization. Therefore, an early diagnosis and treatment to avoid the severe AKI stage are important. While several biomarkers, such as urinary L-FABP and NGAL, can be clinically useful, there is still no gold standard for the early detection of AKI and there are limited therapeutic options against AKI. miRNAs are non-coding and single-stranded RNAs that silence their target genes in the post-transcriptional process and are involved in a wide range of biological processes. Recent accumulated evidence has revealed that miRNAs may be potential biomarkers and therapeutic targets for AKI. In this review article, we summarize the current knowledge about miRNAs as promising biomarkers and potential therapeutic targets for AKI, as well as the challenges in their clinical use.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.