Role of ITK signaling in acute kidney injury in mice: Amelioration of acute kidney injury associated clinical parameters and attenuation of inflammatory transcription factor signaling in CD4+ T cells by ITK inhibition

Th17/Treg balance: the bloom and wane in the pathophysiology of sepsis

Sepsis is a multi-organ dysfunction characterized by an unregulated host response to infection. It is associated with high morbidity, rapid disease progression, and high mortality. Current therapies mainly focus on symptomatic treatment, such as blood volume supplementation and antibiotic use, but their effectiveness is limited. Th17/Treg balance, based on its inflammatory property, plays a crucial role in determining the direction of the inflammatory response and the regression of organ damage in sepsis patients. This review provides a summary of the changes in T-helper (Th) 17 cell and regulatory T (Treg) cell differentiation and function during sepsis, the heterogeneity of Th17/Treg balance in the inflammatory response, and the relationship between Th17/Treg balance and organ damage. Th17/Treg balance exerts significant control over the bloom and wanes in host inflammatory response throughout sepsis.

Insights into Repeated Renal Injury Using RNA-Seq with Two New RPTEC Cell Lines

Renal proximal tubule epithelial cells (RPTECs) are a primary site for kidney injury. We created two RPTEC lines from CD-1 mice immortalized with hTERT (human telomerase reverse transcriptase) or SV40 LgT antigen (Simian Virus 40 Large T antigen). Our hypothesis was that low-level, repeated exposure to subcytotoxic levels of 0.25-2.5 μM cisplatin (CisPt) or 12.5-100 μM aflatoxin B1 (AFB1) would activate distinctive genes and pathways in these two differently immortalized cell lines. RNA-seq showed only LgT cells responded to AFB1 with 1139 differentially expressed genes (DEGs) at 72 h. The data suggested that AFB1 had direct nephrotoxic properties on the LgT cells. However, both the cell lines responded to 2.5 μM CisPt from 3 to 96 h expressing 2000-5000 total DEGs. For CisPt, the findings indicated a coordinated transcriptional program of injury signals and repair from the expression of immune receptors with cytokine and chemokine secretion for leukocyte recruitment; robust expression of synaptic and substrate adhesion molecules (SAMs) facilitating the expression of neural and hormonal receptors, ion channels/transporters, and trophic factors; and the expression of nephrogenesis transcription factors. Pathway analysis supported the concept of a renal repair transcriptome. In summary, these cell lines provide in vitro models for the improved understanding of repeated renal injury and repair mechanisms. High-throughput screening against toxicant libraries should provide a wider perspective of their capabilities in nephrotoxicity.

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

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

LMCD1 is involved in tubulointerstitial inflammation in the early phase of renal fibrosis by promoting NFATc1-mediated NLRP3 activation

Prolonged renal inflammation contributes to fibrosis, which may eventually lead to irreversible chronic kidney disease. Our previous work demonstrated that LIM and cysteine-rich domain 1 (LMCD1) are associated with renal interstitial fibrosis in a 21-day unilateral ureteral obstruction (21UUO) mouse model. Interestingly, based on the gene expression omnibus database, we found that LMCD1 is enhanced in the mouse kidney as early as 5, 7, and 10 days following unilateral ureteral obstruction (UUO), suggesting that LMCD1 may exert its function in an earlier phase. To validate this conjecture, a 7UUO mouse model and a tumor necrosis factor-α (TNF-α)-stimulated HK-2 cell model were established, followed by injection of adenovirus vectors carrying short hairpin RNA targeting LMCD1. LMCD1 silencing ameliorated renal collagen deposition and reduced the expression of profibrotic factors in the 7UUO model. LMCD1 silencing alleviated tubulointerstitial inflammation by mitigating F4/80⁺ cell infiltration, monocyte chemoattractant protein-1 release and nuclear factor-κB activation. In addition, LMCD1 silencing suppressed NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation and nuclear factor of activated T cells 1 (NFATc1) nuclear translocation. Consistent results were obtained in TNF-α-stimulated HK-2 cells in vitro. Mechanistically, the transcriptional coactivator LMCD1 cooperates with the transcription factor NFATc1 to increase NLRP3 expression. Collectively, these findings suggest that LMCD1 participates in tubulointerstitial inflammation via an LMCD1-NFATc1/NLRP3 mechanism. LMCD1 may therefore become a potential target for the control of renal inflammation and fibrosis.

Exogenous glutathione protects against gentamicin-induced acute kidney injury by inhibiting NF-κB pathway, oxidative stress, and apoptosis and regulating PCNA

This study was designed, for the first time, to examine the possible nephroprotective effects of exogenous glutathione (EGSH) (100 mg/kg, intraperitoneally) on gentamicin-induced acute kidney injury (GM-induced AKI). EGSH reduced renal histopathological changes, inflammatory cell infiltration, and improved renal dysfunction in rats with AKI. EGSH ameliorated GM-induced renal oxidative stress by promoting the renal activities of catalase, glutathione peroxidase, and superoxide dismutase and diminishing renal malondialdehyde and serum nitric oxide levels. Interestingly, EGSH inhibited intrinsic apoptosis by downregulating Bax and caspase-3 and upregulating Bcl2 in the kidney of rats with AKI. EGSH decreased GM-induced inflammatory response as reflected by a remarkable decrease in the protein expressions of NF-κB-p65, IL-6, TNF-α, and iNOS and a considerable diminish in myeloperoxidase activity. Finally, EGSH markedly declined proliferative cell nuclear antigen (PCNA) protein expression in the animals with AKI. In summary, EGSH alleviated AKI in rats intoxicated with GM, partially by inhibiting oxidative stress, NF-κB pathway, and intrinsic apoptosis and regulating PCNA.

Immunoregulatory mechanism of acute kidney injury in sepsis: A Narrative Review

Sepsis acute kidney injury (SAKI) is a common complication of sepsis, accounting for 26-50 % of all acute kidney injury (AKI). AKI is an independent risk factor for increased mortality risk in patients with sepsis. The excessive inflammatory cascade reaction in SAKI is one of the main causes of kidney damage. Both the innate immune system and the adaptive immune system are involved in the inflammation process of SAKI. Under the action of endotoxin, neutrophils, monocytes, macrophages, T cells and other complex immune network reactions occur, and a large number of endogenous inflammatory mediators are released, resulting in the amplification and loss of control of the inflammatory response. The study of immune cells in SAKI will help improve the understanding of the immune mechanisms of SAKI, and will lay a foundation for the development of new diagnostic and therapeutic targets. This article reviews the role of known immune mechanisms in the occurrence and development of SAKI, with a view to finding new targets for SAKI treatment.

Pectolinarigenin alleviated septic acute kidney injury via inhibiting Jak2/Stat3 signaling and mitochondria dysfunction

Sepsis is a systemic inflammatory response to infection, where sepsis-associated acute kidney injury (AKI) is a common morbid disease with a high morbidity and mortality, and however at present no effective therapy exists. Increasing evidence have shown that mitochondrial damage and inflammatory response are important initiating factors in pathogenesis of septic AKI. Natural flavonoid pectolinarigenin exerted anti-inflammatory properties in previous studies, while its role in septic AKI remains unknown. In the study, pectolinarigenin administration significantly ameliorated the dramatic rise of serum creatinine and blood urea nitrogen in lipopolysaccharide (LPS)- and cecal ligation/puncture (CLP)-induced septic mice, respectively. Consistently, LPS/CLP-induced renal damage as implied by histopathological score and the increased injury markers NGAL and KIM-1, which was attenuated by pectolinarigenin. Meanwhile, LPS/CLP triggered proinflammatory cytokine production and inflammation related proteins in the kidneys. However, pectolinarigenin inhibited renal expression of IL-6, IL-1β, TNF-α, and MCP-1 to improve inflammatory response. Furthermore, pectolinarigenin upregulated Bcl-2 protein expression and suppressed apoptotic protein of BAX and cleaved caspase-3 in the kidneys of CLP-induced septic AKI. Mechanistically, LPS could induce the high expression of IL-6 and trigger the phosphorylation of Jak2 and Stat3, while pectolinarigenin remarkably reduced their corresponding levels. Notably, CLP-induced kidney injury of mice significantly reduced the expression of PGC-1α, OPA1 and increased the expression of Drp1, Cyt-C, where pectolinarigenin pretreatment significantly restored their corresponding expression in mice. In summary, pectolinarigenin improved septic AKI via inhibiting JAK2/STAT3 signaling and mitochondria dysfunction.

RNF20 deletion causes inflammation in model of sepsis through the NLRP3 activation

Aim: Sepsis is an extremely complex, threatening and difficult-to-treat disease, which can occur at any age and under any underlying disease. RNF20 regulate NF-kappaB (NF-κB) signaling pathway and the transcription of inflammatory factors of target genes. Therefore, it is of great significance to study the function of RNF20 in the clinical treatment of sepsis and its underlying mechanisms.Methods: C57BL/6 mice were subjected to cecal ligation and puncture (CLP) surgery. THP-1 cells were induced with Lipopolysaccharide for 4 h.Results: RNF20 gene, mRNA expression and protein expression were reduced in patients with sepsis and mice with sepsis. Based on RNF20 deletion (RNF20^-/-) mice, these were found to be increased inflammation reactions in RNF20^-/- mice. However, the RNF20 human protein reduced inflammation reactions in mice with sepsis. In vitro model of sepsis, over-expression of RNF20 inhibited inflammation reactions by inducing Vitamin D Receptor (VDR), while down-regulation of RNF20 promoted inflammation reactions through the suppression of VDR. RNF20 protein was interlinked with VDR protein, and VDR protein was also interlinked with NLRP3. Furthermore, VDR promoted NLRP3 ubiquitination and reduced NLRP3 function in vitro model of sepsis.Conclusion: These studies demonstrate that RNF20 suppressed inflammation reactions in models with sepsis through NLRP3 inflammasome and NLRP3 ubiquitination by activating VDR.

Gongronema latifolium leaf extract protects against dexamethasone-induced myocardial cell injury via cardiac oxido-inflammatory molecules modulation

The use of glucocorticoids in the treatment of inflammatory disorders can result in myocardial injury. This study was carried out to investigate the protective effects of ethanolic leaf extract of Gongronema latifolium (GL) in dexamethasone (DEX)-induced myocardial injury. Wistar rats were assigned to 4 groups (n = 6) namely, control, GL, DEX, and DEX+GL groups. DEX (35 μg/kg body weight) was administered subcutaneously to induce myocardial injury, while GL leaf extract (200 mg/kg body weight) was administered orally. Both agents were administered to their respective groups for 14 days. DEX (p < .05) decreased nitric oxide and increased angiotensin-converting enzyme activity compared with the control. Serum superoxide dismutase activity and bilirubin level were decreased (p < .05), while malondialdehyde level was increased (p < .05) in the DEX group. Serum liver enzymes, inflammatory biomarkers (C-reactive protein and interleukin-6), and cardiac injury biomarkers (creatinine kinase, cardiac troponin-T, and lactate dehydrogenase) were significantly (p < .05) increased in the DEX group relative to the control. Administration of GL leaf extract attenuated these changes significantly. The study therefore suggests that GL is beneficial in the treatment of myocardial injury via the downregulation of high serum concentration of cardiac biomarkers, oxidative stress markers, and inflammatory biomarkers released as a result of the insult caused by glucocorticoid administration. PRACTICAL APPLICATIONS: In this study, we demonstrated that prolonged use of dexamethasone resulted in myocardial cell injury via increased production of reactive oxygen species, inflammatory biomarkers, and inhibition of nitric oxide, a potent vasodilator. The leaves extract of Gongronema latifolium elicits the anti-inflammatory and cardioprotective potential as an efficient inhibitor of free radicals with good antioxidant properties. The study provides scientific evidence of the therapeutic ability of the extract of G. latifolium in the treatment of DEX-induced myocardial injury and could be a drug candidate for the treatment of myocardial injury and inflammation in humans.

Screening of Sepsis Biomarkers Based on Bioinformatics Data Analysis

Methods

Gene expression profiles of GSE13904, GSE26378, GSE26440, GSE65682, and GSE69528 were obtained from the National Center for Biotechnology Information (NCBI). The differentially expressed genes (DEGs) were searched using limma software package. Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed to elucidate molecular mechanisms of DEGs and screen hub genes.

Results

A total of 108 DEGs were identified in the study, of which 67 were upregulated and 41 were downregulated. 15 superlative diagnostic biomarkers (CCL5, CCR7, CD2, CD27, CD274, CD3D, GNLY, GZMA, GZMH, GZMK, IL2RB, IL7R, ITK, KLRB1, and PRF1) for sepsis were identified by bioinformatics analysis.

Conclusion

15 hub genes (CCL5, CCR7, CD2, CD27, CD274, CD3D, GNLY, GZMA, GZMH, GZMK, IL2RB, IL7R, ITK, KLRB1, and PRF1) have been elucidated in this study, and these biomarkers may be helpful in the diagnosis and therapy of patients with sepsis.

Role of curcumin in the treatment of acute kidney injury: research challenges and opportunities

BACKGROUND

Acute kidney injury (AKI) is a common complication in clinical inpatients, and it continues a high morbidity and mortality rate despite many clinical treatment measures. AKI is triggered by infections, surgery, heavy metal exposure and drug side effects, but current chemical drugs often fall short of expectations for AKI treatment and have toxic side effects. Therefore, finding new interventions and treatments, especially of natural origin, is of remarkable clinical significance and application. The herbal monomer curcumin is a natural phenolic compound extracted from the plant Curcuma longa and showed various biological activities, including AKI. Furthermore, recent studies have shown that curcumin restores renal function by modulating the immune system and the release of inflammatory mediators, scavenging oxygen free radicals, reducing apoptosis and improving mitochondrial dynamics. However, curcumin has a low bioavailability, which limits its clinical application. For this reason, it is essential to investigate the therapeutic effects and molecular mechanisms of curcumin in AKI, as well as to improve its bioavailability for curcumin formulation development and clinical application.

PURPOSE

This review summarizes the sources, pharmacokinetics, and limitations in the clinical application of curcumin and explores methods to optimize its bioavailability using nanotechnology. In particular, the therapeutic effects and molecular mechanisms of curcumin on AKI are highlighted to provide a theoretical basis for AKI treatment in clinical practices.

METHODS

This review was specifically searched by means of a search of three databases (Web of Science, PubMed and Science Direct), till December 2021. Search terms were "Curcumin", "Acute kidney injury", "AKI", " Pharmacokinetics", "Mitochondria" and "Nano formulations". The retrieved data followed PRISMA criteria (preferred reporting items for systematic review) RESULTS: Studies have shown that curcumin responded to AKI-induced renal injury and restored renal tubular epithelial cell function by affecting multiple signaling pathways in AKI models induced by factors such as cisplatin, lipopolysaccharide, ischemia/reperfusion, gentamicin and potassium dichromate. Curcumin was able to affect NF-κB signaling pathway and reduce the expression of IL-1β, IL-6, IL-8 and TNF-α, thus preventing renal inflammatory injury. In the prevention of renal tubular oxidative damage, curcumin reduced ROS production by activating the activity of Nrf2, HO-1 and PGC-1α. In addition, curcumin restored mitochondrial homeostasis by upregulating OPA1 and downregulating DRP1 expression, while reducing apoptosis by inhibiting the caspase-3 apoptotic pathway. In addition, due to the low bioavailability and poor absorption of curcumin in vivo, curcumin nanoformulations including nanoparticles, liposomes, and polymeric micelles are formulated to improve the bioavailability.

CONCLUSION

This review provides new ideas for the use of curcumin in the prevention and treatment of AKI by modulating the molecular targets of several different cellular signaling pathways.

Kynurenine Pathway-An Underestimated Factor Modulating Innate Immunity in Sepsis-Induced Acute Kidney Injury?

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, and it accounts for about half of the cases of acute kidney injury (AKI). Although sepsis is the most frequent cause of AKI in critically ill patients, its pathophysiological mechanisms are not well understood. Sepsis has the ability to modulate the function of cells belonging to the innate immune system. Increased activity of indoleamine 2,3-dioxygenase 1 (IDO1) and production of kynurenines are the major metabolic pathways utilized by innate immunity cells to maintain immunological tolerance. The activation of the kynurenine pathway (KP) plays a dual role in sepsis—in the early stage, the induction of IDO1 elicits strong proinflammatory effects that may lead to tissue damage and septic shock. Afterwards, depletion of tryptophan and production of kynurenines contribute to the development of immunosuppression that may cause the inability to overpower opportunistic infections. The presented review provides available data on the various interdependencies between elements of innate immunity and sepsis-induced AKI (SAKI) with particular emphasis on the immunomodulatory significance of KP in the above processes. We believe that KP activation may be one of the crucial, though underestimated, components of a deregulated host response to infection during SAKI.

The Study on the Regulation of Th Cells by Mesenchymal Stem Cells Through the JAK-STAT Signaling Pathway to Protect Naturally Aged Sepsis Model Rats

Sepsis is the leading cause of death among patients, especially elderly patients, in intensive care units worldwide. In this study, we established a sepsis model using naturally aged rats and injected 5×10⁶ umbilical cord-derived MSCs via the tail vein. Each group of rats was analyzed for survival, examined for biochemical parameters, stained for organ histology, and analyzed for the Th cell subpopulation ratio and inflammatory cytokine levels by flow cytometry. Western blotting was performed to detect the activity of the JAK-STAT signaling pathway. We designed the vitro experiments to confirm the regulatory role of MSCs, and verified the possible mechanism using JAK/STAT inhibitors. It was revealed from the experiments that the 72 h survival rate of sepsis rats treated with MSCs was significantly increased, organ damage and inflammatory infiltration were reduced, the levels of organ damage indicators were decreased, the ratios of Th1/Th2 and Th17/Treg in peripheral blood and spleen were significantly decreased, the levels of pro-inflammatory cytokines such as IL-6 were decreased, the levels of anti-inflammatory cytokines such as IL-10 were increased, and the levels of STAT1 and STAT3 phosphorylation were reduced. These results were validated in in vitro experiments. Therefore, this study confirms that MSCs can control the inflammatory response induced by sepsis by regulating Th cells and inflammatory factors, and that this leads to the reduction of tissue damage, protection of organ functions and ultimately the improvement of survival in aged sepsis model rats. Inhibition of the JAK-STAT signaling pathway was surmised that it may be an important mechanism for their action.