Pioglitazone Ameliorates Renal Ischemia-Reperfusion Injury via Inhibition of NF-κB Activation and Inflammation in Rats

Pioglitazone treatment mitigates cardiovascular bioprosthetic degeneration in a chronic kidney disease model

Aims

Chronic kidney disease (CKD) is a risk factor for the development of cardiovascular diseases, e.g., atherosclerosis and calcific aortic valve disease, leading inevitably to valve replacement surgery. CKD patients with bioprosthetic cardiovascular grafts, in turn, have a higher risk of premature graft degeneration. Peroxisome proliferator-activated receptor gamma (PPARγ) activation by pioglitazone has cardio-renal protective properties, and research using a heterotopic valve implantation model has shown anti-degenerative effects of PPARγ activation on bioprosthetic valved grafts (BVG) in rats. The present work aims to analyze a potential protective effect of pioglitazone treatment on BVG in an adenine-induced rat model of CKD.

Methods and Results

BVG of Sprague Dawley rats were heterotopically implanted in Wistar rats in an infrarenal position for 4 and 8 weeks. Animals were distributed into three groups for each time point: 1) control group receiving standard chow, 2) CKD group receiving 0.25% adenine and 3) CKD + pioglitazone group (300 mg per kg of 0.25% adenine chow). BVG function was analyzed by echocardiography. Plasma analytes were determined and explanted grafts were analyzed by semi-quantitative real-time PCR, Western blot analysis, histology and immunohistology.PPARγ activation significantly reduced CKD-induced calcification of aortic and valvular segments of BVG by 44% and 53%, respectively. Pioglitazone treatment significantly also reduced CKD-induced intima hyperplasia by 60%. Plasma analysis revealed significantly attenuated potassium and phosphate levels after pioglitazone treatment. Moreover, PPARγ activation led to significantly decreased interleukin-6 gene expression (by 57%) in BVG compared to CKD animals. Pioglitazone treatment leads to functional improvement of BVG.

Conclusion

This study broadens the understanding of the potential value of PPARγ activation in cardio-renal diseases and delineates pioglitazone treatment as a valuable option to prevent bioprosthetic graft failure in CKD. Further mechanistic studies, e.g., using small molecules activating PPARγ signaling pathways, are necessary for the evaluation of involved mechanisms. Additionally, the translation into pre-clinical studies using large animals is intended as the next research project.

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.

Protective effects of pioglitazone in renal ischemia-reperfusion injury (RIRI): focus on oxidative stress and inflammation

BACKGROUND

Renal ischemia-reperfusion injury (RIRI) is a critical phenomenon that compromises renal function and is the most serious health concern related to acute kidney injury (AKI). Pioglitazone (Pio) is a known agonist of peroxisome proliferator-activated receptor-gamma (PPAR-γ). PPAR-γ is a nuclear receptor that regulates genes involved in inflammation, metabolism, and cellular differentiation. Activation of PPAR-γ is associated with antiinflammatory and antioxidant effects, which are relevant to the pathophysiology of RIRI. This study aimed to investigate the protective effects of Pio in RIRI, focusing on oxidative stress and inflammation.

METHODS

We conducted a comprehensive literature search using electronic databases, including PubMed, ScienceDirect, Web of Science, Scopus, and Google Scholar.

RESULTS

The results of this study demonstrated that Pio has antioxidant, anti-inflammatory, and anti-apoptotic activities that counteract the consequences of RIRI. The study also discussed the underlying mechanisms, including the modulation of various pathways such as TNF-α, NF-κB signaling systems, STAT3 pathway, KIM-1 and NGAL pathways, AMPK phosphorylation, and autophagy flux. Additionally, the study presented a summary of various animal studies that support the potential protective effects of Pio in RIRI.

CONCLUSION

Our findings suggest that Pio could protect the kidneys from RIRI by improving antioxidant capacity and decreasing inflammation. Therefore, these findings support the potential of Pio as a therapeutic strategy for preventing RIRI in different clinical conditions.

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.

A Novel Peroxisome Proliferator-Activated Receptor Gamma/Nuclear Factor-Kappa B Activation Pathway is Involved in the Protective Effect of Adipose-Derived Mesenchymal Stem Cells Against Ischemia-Reperfusion Lung Injury

BACKGROUND

Adipose-derived stem cells (ADSCs) are well-recognized for their remarkable ability to suppress ischemia-reperfusion lung injury (IRLI). The primary objective of this investigation was to elucidate the underlying mechanism through which ADSCs exert protective effects against IRLI.

METHODS

A warm hilar occlusion model in C57BL6J mice was used. Hilar occlusion was achieved for 1 hour (ischemic), and after 1 hour the occlusion was released (reperfusion) to recover for 3 hours. RNA sequencing, the physiological function, pathway activation, and expression of inflammatory cytokines were evaluated.

RESULTS

Lung gas exchange and pulmonary edema were significantly improved in the IRLI/ADSCs group compared with the IRLI group. RNA sequencing results suggested that the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor-kappa B (NF-κB) pathway was involved in the effect of the ADSCs. Administration of a PPARγ antagonist in the IRLI/ADSC group resulted in the deterioration of the physiological function. Furthermore, the PPARγ protein expression level decreased, the NF-κB protein expression level increased, and inflammatory cytokine parameters from lung tissue and blood sample worsened in the PPARγ antagonist-administered group.

CONCLUSION

Administration of ADSCs exerted a significant protective effect against IRLI in mice, and the effect is attributed to the activation of the PPARγ/NF-κB pathway.

The nuclear factor kappa B signaling pathway is a master regulator of renal fibrosis

Renal fibrosis is increasingly recognized as a global public health problem. Acute kidney injury (AKI) and chronic kidney disease (CKD) both result in renal fibrosis. Oxidative stress and inflammation play central roles in progressive renal fibrosis. Oxidative stress and inflammation are closely linked and form a vicious cycle in which oxidative stress induces inflammation through various molecular mechanisms. Ample evidence has indicated that a hyperactive nuclear factor kappa B (NF-ƙB) signaling pathway plays a pivotal role in renal fibrosis. Hyperactive NF-ƙB causes the activation and recruitment of immune cells. Inflammation, in turn, triggers oxidative stress through the production of reactive oxygen species and nitrogen species by activating leukocytes and resident cells. These events mediate organ injury through apoptosis, necrosis, and fibrosis. Therefore, developing a strategy to target the NF-ƙB signaling pathway is important for the effective treatment of renal fibrosis. This Review summarizes the effect of the NF-ƙB signaling pathway on renal fibrosis in the context of AKI and CKD (immunoglobulin A nephropathy, membranous nephropathy, diabetic nephropathy, hypertensive nephropathy, and kidney transplantation). Therapies targeting the NF-ƙB signaling pathway, including natural products, are also discussed. In addition, NF-ƙB-dependent non-coding RNAs are involved in renal inflammation and fibrosis and are crucial targets in the development of effective treatments for kidney disease. This Review provides a clear pathophysiological rationale and specific concept-driven therapeutic strategy for the treatment of renal fibrosis by targeting the NF-ƙB signaling pathway.

Pioglitazone ameliorates cisplatin-induced testicular toxicity by attenuating oxidative stress and inflammation via TLR4/MyD88/NF-κB signaling pathway

BACKGROUND

Cisplatin (CIS) is a chemotherapeutic agent widely used to cure several cancers. It exerts detrimental cellular effects that restrain its clinical application as an antineoplastic agent, as testicular damage. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist, is used to treat type-2 diabetes mellitus. PIO has been reported to exert anti-inflammatory and antioxidant effects in different tissues. The present study aimed to investigate the effect of PIO in a rat model of cisplatin-induced testicular toxicity and address the possible role of the Toll-like receptors (TLR4) / myeloid differentiation factor 88 (MyD88) / nuclear factor-kappa B (NF-kB) signal pathway.

METHODS

Rats received a single dose of cisplatin (7 mg/kg, IP) on the first day and PIO (10 mg/kg, P.O.) for 7 days. At the end of the treatment period, rats were killed. Testicular weights, histopathological alterations, and serum testosterone levels were determined. Moreover, tissue samples were collected for the estimation of oxidative stress parameters, inflammatory markers, and the determination of TLR4 /MyD88/NF-kB signaling.

RESULTS

Concurrent PIO administration with CIS markedly improved testicular weights, histopathological alteration, and serum testosterone level changes. Moreover, Concurrent PIO administration abrogated oxidative stress status and inflammatory markers caused by CIS administration. Furthermore, PIO inhibited the expression levels of TLR4, MyD88, and NF-κBp65, proteins that are activated by CIS administration.

CONCLUSION

These findings suggested that PIO can protect against cisplatin-induced testicular toxicity in rats through inhibition of the TLR4 /MyD88/NF-kB signal pathway.

Pioglitazone attenuates tamoxifen-induced liver damage in rats via modulating Keap1/Nrf2/HO-1 and SIRT1/Notch1 signaling pathways: In-vivo investigations, and molecular docking analysis

BACKGROUND

Tamoxifen (TAM) is a chemotherapeutic drug widely utilized to treat breast cancer. On the other hand, it exerts deleterious cellular effects in clinical applications as an antineoplastic agent, such as liver damage and cirrhosis. TAM-induced hepatic toxicity is mainly attributed to oxidative stress and inflammation. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist, is utilized to treat diabetes mellitus type-2. PIO has been reported to exert anti-inflammatory and antioxidant effects in different tissues. This research assessed the impact of PIO against TAM-induced hepatic intoxication.

METHODS

Rats received PIO (10 mg/kg) and TAM (45 mg/kg) orally for 10 days.

RESULTS

TAM increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT), triggered several histopathological alterations, NF-κB p65, increased hepatic oxidative stress, and pro-inflammatory cytokines. PIO protects against TAM-induced liver dysfunction, reduced malondialdehyde (MDA), and pro-inflammatory markers along with improved hepatic antioxidants. Moreover, PIO, increased hepatic Bcl-2 expression while reducing Bax expression and caspase-3 levels. In addition, PIO decreased Keap-1, Notch1, and Hes-1 while upregulated HO-1, Nrf2, and SIRT1. Molecular docking showed the binding affinity of PIO for Keap-1, NF-κB, and SIRT1.

CONCLUSION

PIO mitigated TAM hepatotoxicity by decreasing apoptosis, inflammation, and oxidative stress. The protecting ability of PIO was accompanied by reducing Keap-1 and NF-κB and regulating Keap1/Nrf2/HO-1 and Sirt1/Notch1 signaling. A schematic diagram illustrating the protective effect of PIO against TAM hepatotoxicity. PIO prevented TAM-induced liver injury by regulating Nrf2/HO-1 and SIRT1/Notch1 signaling and mitigating oxidative stress, inflammation, and apoptosis.

SIRT1 alleviates insulin resistance and respiratory distress in late preterm rats by activating QKI5-mediated PPARγ/PI3K/AKT pathway

Neonatal respiratory distress syndrome (NRDS) is a common complication of gestational diabetes mellitus (GDM) and late preterm births. Research suggests that SIRT1 was involved in LPS-induced acute respiratory distress syndrome, but its mechanism remains to be further explored. Here, pregnant rats were intraperitoneally injected with 45 mg/Kg streptozotocin at day 0 of gestation to induce GDM and injected with LPS at day 17 of gestation to induce late preterm birth. Pioglitazone (a PPARγ agonist) was administered from day 17 to parturition in GDM group, and it was administered for 3 days before LPS injection in late preterm birth group. SRT1720 (a SIRT1 activator) was administered by oral gavage from day 0 to day 17 in both groups. Our data showed that activation of SIRT1 or PPARγ alleviated the abnormal blood glucose metabolism and lung tissue injury, downregulated expression of surfactant proteins (SP-B and SP-C), and decreased activation of the PI3K/AKT pathway induced by GDM and late preterm birth in neonatal rats. Moreover, an insulin resistance model was established by treating primary AT-II cells with insulin. Activation of SIRT1 reversed insulin-induced reduction in cell proliferation, glucose consumption, SP-B and SP-C expression, and the activity of the PI3K/AKT pathway and increase in cellular inflammation and apoptosis. Mechanistically, SIRT1 upregulated PPARγ expression via deacetylation of QKI5, an RNA binding protein that can stabilize its target mRNA molecules, and then activated the PI3K/AKT pathway. In conclusion, SIRT1 promotes the expression of PPARγ via upregulation of QKI5 and activates the PI3K/AKT pathway, thus mitigating NRDS caused by GDM and late preterm birth.

Targeting PPARs for therapy of atherosclerosis: A review

Atherosclerosis, a chief pathogenic factor of cardiovascular disease, is associated with many factors including inflammation, dyslipidemia, and oxidative stress. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors and are widely expressed with tissue- and cell-specificity. They control multiple genes that are involved in lipid metabolism, inflammatory response, and redox homeostasis. Given the diverse biological functions of PPARs, they have been extensively studied since their discovery in 1990s. Although controversies exist, accumulating evidence have demonstrated that PPAR activation attenuates atherosclerosis. Recent advances are valuable for understanding the mechanisms of action of PPAR activation. This article reviews the recent findings, mainly from the year of 2018 to present, including endogenous molecules in regulation of PPARs, roles of PPARs in atherosclerosis by focusing on lipid metabolism, inflammation, and oxidative stress, and synthesized PPAR modulators. This article provides information valuable for researchers in the field of basic cardiovascular research, for pharmacologists that are interested in developing novel PPAR agonists and antagonists with lower side effects as well as for clinicians.

Exosomal microRNA-342-5p secreted from adipose-derived mesenchymal stem cells mitigates acute kidney injury in sepsis mice by inhibiting TLR9

BACKGROUND

Sepsis-related acute kidney injury (AKI) is an inflammatory disease associated with extremely high mortality and health burden. This study explored the possibility of exosomes secreted by adipose-derived mesenchymal stem cells (AMSCs) serving as a carrier for microRNA (miR)-342-5p to alleviate sepsis-related AKI and investigated the possible mechanism.

METHODS

Serum was obtained from 30 patients with sepsis-associated AKI and 30 healthy volunteers for the measurement of miR-342-5p, blood urea nitrogen (BUN), and serum creatinine (SCr) levels. For in vitro experiments, AMSCs were transfected with LV-miR-342-5p or LV-miR-67 to acquire miR-342-5p-modified AMSCs and miR-67-modified AMSCs, from which the exosomes (AMSC-Exo-342 and AMSC-Exo-67) were isolated. The human renal proximal tubular epithelial cell line HK-2 was induced by lipopolysaccharide (LPS) to construct a cellular model of sepsis. The expression of Toll-like receptor 9 (TLR9) was also detected in AKI cells and mouse models. The interaction between miR-342-5p and TLR9 was predicted by dual luciferase reporter gene assay.

RESULTS

Detection on clinical serum samples showed that BUN, SCr, and TLR9 were elevated and miR-342-5p level was suppressed in the serum of patients with sepsis-associated AKI. Transfection with LV-miR-342-5p reinforced miR-342-5p expression in AMSCs and AMSC-secreted exosomes. miR-342-5p negatively targeted TLR9. LPS treatment enhanced TLR9 expression, reduced miR-342-5p levels, suppressed autophagy, and increased inflammation in HK-2 cells, while the opposite trends were observed in LPS-induced HK-2 cells exposed to AMSC-Exo-342, Rapa, miR-342-5p mimic, or si-TLR9. Additionally, the effects of AMSC-Exo-342 on autophagy and inflammation in LPS-induced cells could be weakened by 3-MA or pcDNA3.1-TLR9 treatment. Injection of AMSC-Exo-342 enhanced autophagy, mitigated kidney injury, suppressed inflammation, and reduced BUN and SCr levels in sepsis-related AKI mouse models.

CONCLUSION

miR-342-5p transferred by exosomes from miR-342-5p-modified AMSCs ameliorated AKI by inhibiting TLR9 to accelerate autophagy.

Mitoglitazone ameliorates renal ischemia/reperfusion injury by inhibiting ferroptosis via targeting mitoNEET

Ischemia/reperfusion- (I/R-) induced injury is unavoidable and a major risk factor for graft failure and acute rejection following kidney transplantation. However, few effective interventions are available to improve the outcome due to the complicated mechanisms and lack of appropriate therapeutic targets. Hence, this research aimed to explore the effect of the thiazolidinedione (TZD) compounds on I/R-induced kidney damage. One of the main causes of renal I/R injury is the ferroptosis of renal tubular cells. In this study, compared with the antidiabetic TZD pioglitazone (PGZ), we found its derivative mitoglitazone (MGZ) exerted significantly inhibitory effects on erastin-induced ferroptosis by suppressing mitochondrial membrane potential hyperpolarization and lipid ROS production in HEK293 cells. Moreover, MGZ pretreatment remarkably alleviated I/R-induced renal damages by inhibiting cell death and inflammation, upregulating the expression of glutathione peroxidase 4 (GPX4), and reducing iron-related lipid peroxidation in C57BL/6 N mice. Additionally, MGZ exhibited excellent protection against I/R-induced mitochondrial dysfunction by restoring ATP production, mitochondrial DNA copy numbers, and mitochondrial morphology in kidney tissues. Mechanistically, molecular docking and surface plasmon resonance experiments demonstrated that MGZ exhibited a high binding affinity with the mitochondrial outer membrane protein mitoNEET. Collectively, our findings indicated the renal protective effect of MGZ was closely linked to regulating the mitoNEET-mediated ferroptosis pathway, thus offering potential therapeutic strategies for ameliorating I/R injuries.

Transcriptional regulation of proximal tubular metabolism in acute kidney injury

The kidney, and in particular the proximal tubule (PT), has a high demand for ATP, due to its function in bulk reabsorption of solutes. In normal PT, ATP levels are predominantly maintained by fatty acid β-oxidation (FAO), the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation. The normal PT also undertakes gluconeogenesis and metabolism of amino acids. Acute kidney injury (AKI) results in profound PT metabolic alterations, including suppression of FAO, gluconeogenesis, and metabolism of some amino acids, and upregulation of glycolytic enzymes. Recent studies have elucidated new transcriptional mechanisms regulating metabolic pathways in normal PT, as well as the metabolic switch in AKI. A number of transcription factors have been shown to play important roles in FAO, which are themselves downregulated in AKI, while hypoxia-inducible factor 1α, which is upregulated in ischemia-reperfusion injury, is a likely driver of the upregulation of glycolytic enzymes. Transcriptional regulation of amino acid metabolic pathways is less well understood, except for catabolism of branched-chain amino acids, which is likely suppressed in AKI by upregulation of Krüppel-like factor 6. This review will focus on the transcriptional regulation of specific metabolic pathways in normal PT and in AKI, as well as highlighting some of the gaps in knowledge and challenges that remain to be addressed.

Identification and Verification of Potential Biomarkers in Renal Ischemia-Reperfusion Injury by Integrated Bioinformatic Analysis

Background

Renal ischemia-reperfusion injury (RIRI) plays an important role in the poor prognosis of patients with renal transplants. However, the potential targets and mechanism of IRI are still unclear.

Method

Differential gene expression (DEG) analysis and weighted correlation network analysis (WGCNA) were performed on the GSE27274 dataset. Pathway enrichment analysis on the DEGs was performed. To identify the hub DEGs, we constructed a protein-protein interaction (PPI) network. Finally, the hub genes were verified, and candidate drugs were screened from the DsigDB database.

Results

A hundred DEGs and four hub genes (Atf3, Psmb6, Psmb8, and Psmb10) were screened out. Pathway enrichment analysis revealed that 100 DEGs were mainly enriched in apoptosis and the TNF signaling pathway. The four hub genes were verified in animal models and another dataset (GSE148420). Thereafter, a PPI network was used to identify the four hub genes (Atf3, Psmb6, Psmb8, and Psmb10). Finally, eight candidate drugs were identified as potential drugs.

Conclusion

Three hub genes (Psmb6, Psmb8, and Psmb10) were associated with RIRI and could be potential novel biomarkers for RIRI.

THE POTENTIAL RENOPROTECTIVE EFFECT OF TILIANIN IN RENAL ISCHEMIA REPERFUSION INJURY IN MALE RAT MODEL

OBJECTIVE

The aim: To determine whether Tilianin (TIL) may have Nephroprotective effects on bilateral renal IRI in rats by analyzing kidney function biomarkers U and Cr, inflammatory cytokines like TNF α and IL-1β, antioxidant marker total anti-oxidant Capacity (TAC), anti-apoptotic markers caspase-3, and histopathological scores.

PATIENTS AND METHODS

Materials and methods: 20 rats divided into even 4 groups as: Sham group: Rats underwent median laparotomies without having their ischemia induced. Control group: Rats had bilateral renal ischemia for 30 minutes, followed by 2 hours of reperfusion. Vehicle group: 30 minutes prior to the onset of ischemia, rats were given a pretreatment of corn oil and DMSO. Tilianin treated group: Rats administered Tilianin 5 mg/kg for 30 min prior to ischemia induction, then IRI.

RESULTS

Results: The study found that the serum levels of TNF, IL-1, caspase-3, urea and creatinine, as well as TNF and creatinine in the Tilianin group were significantly lower than those of the control and vehicle groups. On the other hand, it revealed that TAC levels are remarkably higher in the Tilianin group than they are in the control and vehicle groups.

CONCLUSION

Conclusions: This study concluded that Tilianin have a Nephroprotective effect via multiple impacts as anti-inflammatory, anti-apoptotic, and anti-oxidant agents.

Possible Implication of Nrf2, PPAR-γ and MAPKs Signaling in the Protective Role of Mangiferin against Renal Ischemia/Reperfusion in Rats

Mangiferin (Mang) is a known glucosylxanthone that has proven its shielding effect against ischemia/reperfusion (Is/R). However, its full underlying mechanistic perspective against renal Is/R induced lesions is not fully revealed. Consequently, the purpose of this study is to track further non-investigated modulatory signals of Mang against the renal Is/R model involving nuclear factor erythroid 2-related factor (Nrf)2/heme oxygenase (HO)-1, peroxisome proliferator-activated receptor (PPAR)-γ/nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) signaling. To ratify our aim, Mang was administrated (20 mg/kg, i.p for seven days) before the induction of bilateral Is/R. Mechanistic maneuver revealed that Mang balanced oxidative state via increasing the expression of the antioxidant Nrf2/HO-1 cue with subsequent enhancement of GSH besides MDA lessening. Additionally, Mang enhanced PPAR-γ mRNA expression and declined p-p38 MAPK and p-JNK expression with concomitant NF-κB downsizing leading to iNOS/NOx and TNF-α rebating. Furthermore, the Mang anti-apoptotic trait was affirmed by enriching Bcl-2 expression as well as decreasing Bax and caspase-3 expression. All these potentials were in the line with the molecular docking results and the improved histopathological findings and renal function biomarkers. Consequently, Mang provided plausible protective mechanisms against renal Is/R-related events, possibly by amending oxidative status, inflammatory mediators, and apoptotic cell death through the involvement of Nrf2, PPAR-γ, MAPK, JNK, and NF-κB signaling.

Pioglitazone modulates immune activation and ameliorates inflammation induced by injured renal tubular epithelial cells via PPARγ/miRNA‑124/STAT3 signaling

Acute kidney injury (AKI) is commonly a result of renal ischemia reperfusion injury (IRI), which produces clinical complications characterized by the rapid deterioration of renal function, leading to chronic kidney disease and increases the risk of morbidity and mortality. Currently, only supportive treatment is available. AKI, which is accompanied by immune activation and inflammation, is caused by proximal tubular injury. The present study investigated the role of tubular epithelial cells as drivers of inflammation in renal IRI and their potential function as antigen-presenting cells, as well as the molecular mechanisms by which peroxisome proliferator-activated receptor-γ (PPARγ) agonists [such as pioglitazone (Pio)] exert reno-protective action in renal IRI. A total of 50 Wistar male albino rats were divided into five groups: Sham + DMSO, Sham + Pio, IRI + DMSO, IRI + prophylactic preoperative (pre) Pio and IRI + postoperative Pio. The histopathological changes in renal tissue samples and the renal epithelial cell expression of CD86, miRNA-124, STAT3, pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and Arginase-II were analyzed by immunohistochemistry, reverse transcription-quantitative PCR, western blotting and ELISA respectively. IRI was a potent inducer for CD86 immunoexpression. An ameliorative action of Pio was demonstrated via decreased CD86 immunoexpression, upregulation of miRNA-124, decreased STAT3 expression and beneficial anti-inflammatory effects. The tubular epithelium served a notable role in the inflammatory response in renal IRI. Pio exerted its anti-inflammatory effects via PPARγ/miRNA-124/STAT3 signaling.

Protective Effects of PPARγ on Renal Ischemia-Reperfusion Injury by Regulating miR-21

Renal ischemia-reperfusion injury (RIRI) is a common pathological process that causes kidney injury. Previous studies have indicated that both peroxisome proliferator-activated receptor γ (PPARγ) and microRNA-21 (miR-21) exert protective effects against RIRI. However, their relationship is not well understood. In the present study, we investigated the role of the PPARγ/miR-21/programmed cell death 4 (PDCD4) axis in IRI, both in vivo and in vitro. In vitro cell hypoxia/reoxygenation (H/R) and in vivo RIRI models were established, and cell viability, cell apoptosis, and key molecule expression profiles were analyzed. Our results showed that both PPARγ and miR-21 had protective effects against RIRI to varying degrees, and there was an interaction between PPARγ and miR-21. PPARγ could promote the expression of miR-21 and partially protect against RIRI by reducing the level of the miR-21 target protein (PDCD4). Our findings underscore the potential utility of future clinical investigations of PPARγ activation and targeting of the underlying miR-21/PDCD4/caspase-3 pathway, which may participate in the pathogenesis of human IRI.

PCSK9 and Other Metabolic Targets to Counteract Ischemia/Reperfusion Injury in Acute Myocardial Infarction and Visceral Vascular Surgery

Ischemia/reperfusion (I/R) injury complicates both unpredictable events (myocardial infarction and stroke) as well as surgically-induced ones when transient clampage of major vessels is needed. Although the main cause of damage is attributed to mitochondrial dysfunction and oxidative stress, the use of antioxidant compounds for protection gave poor results when challenged in clinics. More recently, there is an assumption that, in humans, profound metabolic changes may prevail in driving I/R injury. In the present work, we narrowed the field of search to I/R injury in the heart/brain/kidney axis in acute myocardial infarction, major vascular surgery, and to the current practice of protection in both settings; then, to help the definition of novel strategies to be translated clinically, the most promising metabolic targets with their modulatory compounds—when available—and new preclinical strategies against I/R injury are described. The consideration arisen from the broad range of studies we have reviewed will help to define novel therapeutic approaches to ensure mitochondrial protection, when I/R events are predictable, and to cope with I/R injury, when it occurs unexpectedly.

The Role of Peroxisome Proliferator-Activated Receptors in Kidney Diseases

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors. Accumulating evidence suggests that PPARs may play an important role in the pathogenesis of kidney disease. All three members of the PPAR subfamily, PPARα, PPARβ/δ, and PPARγ, have been implicated in many renal pathophysiological conditions, including acute kidney injury, diabetic nephropathy, and chronic kidney disease, among others. Emerging data suggest that PPARs may be potential therapeutic targets for renal disease. This article reviews the physiological roles of PPARs in the kidney and discusses the therapeutic utility of PPAR agonists in the treatment of kidney disease.

Nuclear receptors in renal health and disease

As a major social and economic burden for the healthcare system, kidney diseases contribute to the constant increase of worldwide deaths. A deeper understanding of the underlying mechanisms governing the etiology, development and progression of kidney diseases may help to identify potential therapeutic targets. As a superfamily of ligand-dependent transcription factors, nuclear receptors (NRs) are critical for the maintenance of normal renal function and their dysfunction is associated with a variety of kidney diseases. Increasing evidence suggests that ligands for NRs protect patients from renal ischemia/reperfusion (I/R) injury, drug-induced acute kidney injury (AKI), diabetic nephropathy (DN), renal fibrosis and kidney cancers. In the past decade, some breakthroughs have been made for the translation of NR ligands into clinical use. This review summarizes the current understanding of several important NRs in renal physiology and pathophysiology and discusses recent findings and applications of NR ligands in the management of kidney diseases.

Pioglitazone Is a Mild Carrier-Dependent Uncoupler of Oxidative Phosphorylation and a Modulator of Mitochondrial Permeability Transition

Pioglitazone (PIO) is an insulin-sensitizing antidiabetic drug, which normalizes glucose and lipid metabolism but may provoke heart and liver failure and chronic kidney diseases. Both therapeutic and adverse effects of PIO can be accomplished through mitochondrial targets. Here, we explored the capability of PIO to modulate the mitochondrial membrane potential (ΔΨ_m) and the permeability transition pore (mPTP) opening in different models in vitro. ΔΨ_m was measured using tetraphenylphosphonium and the fluorescent dye rhodamine 123. The coupling of oxidative phosphorylation was estimated polarographically. The transport of ions and solutes across membranes was registered by potentiometric and spectral techniques. We found that PIO decreased ΔΨ_m in isolated mitochondria and intact thymocytes and the efficiency of ADP phosphorylation, particularly after the addition of Ca²⁺. The presence of the cytosolic fraction mitigated mitochondrial depolarization but made it sustained. Carboxyatractyloside diminished the PIO-dependent depolarization. PIO activated proton transport in deenergized mitochondria but not in artificial phospholipid vesicles. PIO had no effect on K⁺ and Ca²⁺ inward transport but drastically decreased the mitochondrial Ca²⁺-retention capacity and protective effects of adenine nucleotides against mPTP opening. Thus, PIO is a mild, partly ATP/ADP-translocase-dependent, uncoupler and a modulator of ATP production and mPTP sensitivity to Ca²⁺ and adenine nucleotides. These properties contribute to both therapeutic and adverse effects of PIO.