HSPA12A promotes c-Myc lactylation-mediated proliferation of tubular epithelial cells to facilitate renal functional recovery from kidney ischemia/reperfusion injury.

Proliferation of renal tubular epithelial cells (TEC) is essential for restoring tubular integrity and thereby to support renal functional recovery from kidney ischemia/reperfusion (KI/R) injury. Activation of transcriptional factor c-Myc promotes TEC proliferation following KI/R; however, the mechanism regarding c-Myc activation in TEC is incompletely known. Heat shock protein A12A (HSPA12A) is an atypic member of HSP70 family. In this study, we found that KI/R decreased HSPA12A expression in mouse kidneys and TEC, while ablation of HSPA12A in mice impaired TEC proliferation and renal functional recovery following KI/R. Gain-of-functional studies demonstrated that HSPA12A promoted TEC proliferation upon hypoxia/reoxygenation (H/R) through directly interacting with c-Myc and enhancing its nuclear localization to upregulate expression of its target genes related to TEC proliferation. Notably, c-Myc was lactylated in TEC after H/R, and this lactylation was enhanced by HSPA12A overexpression. Importantly, inhibition of c-Myc lactylation attenuated the HSPA12A-induced increases of c-Myc nuclear localization, proliferation-related gene expression, and TEC proliferation. Further experiments revealed that HSPA12A promoted c-Myc lactylation via increasing the glycolysis-derived lactate generation in a Hif1α-dependent manner. The results unraveled a role of HSPA12A in promoting TEC proliferation and facilitating renal recovery following KI/R, and this role of HSPA12A was achieved through increasing lactylation-mediated c-Myc activation. Therefore, targeting HSPA12A in TEC might be a viable strategy to promote renal functional recovery from KI/R injury in patients.

MicroRNA-216a-5p Alleviates Acute Kidney Injury of Mice via Suppressing FAS Ligand Expression.

INTRODUCTION: The aim of this present work was to investigate the mechanism of the microRNA (miR)-216a-5p/FASL axis in mice with acute kidney injury (AKI). METHODS: Mice kidney ischemia/reperfusion (I/R) injury was used as AKI models in this study. I/R mice were injected with miR-216a-5p- and FASL-related constructs to investigate potential mechanisms of kidney protection. Kidney function, inflammation, oxidative stress, and kidney cell apoptosis were assessed after 24 h of reperfusion. In vitro, the hypoxia-reoxygenation (H/R) model was used with kidney tubular epithelial cells (TECs) to mimic kidney I/R injury. H/R-treated TECs were transfected with miR-216a-5p- and FASL-related constructs to detect cell viability, inflammation, and oxidative stress. MiR-216a-5p and FASL expression levels in mouse kidney tissues and in H/R-treated TECs were detected. RESULTS: MiR-216a-5p was downregulated and FASL was upregulated in kidney tissues of I/R mice and H/R-treated TECs. Upregulating miR-216a-5p attenuated kidney cell apoptosis and the damage of kidney function, and reduced inflammatory factor levels and oxidative stress response in kidney tissues of I/R mice. Upregulating miR-216a-5p advanced cell viability and reduced inflammatory factor levels and oxidative stress response in H/R-treated TECs. Downregulation of FASL effectively reversed the influences of downregulation of miR-216a-5p on kidney injury in mice and kidney TEC survival. CONCLUSION: Our study reveals that miR-216a-5p reduces I/R-induced pathological kidney damage in AKI via suppressing FASL.

Ferroptosis and cuproptposis in kidney Diseases: dysfunction of cell metabolism.

Metal ions play an important role in living organisms and are involved in essential physiological activities. However, the overload state of ions can cause excess free radicals, cell damage, and even cell death. Ferroptosis and cuproptosis are specific forms of cell death that are distinct from apoptosis, necroptosis, and other regulated cell death. These unique modalities of cell death, dependent on iron and copper, are regulated by multiple cellular metabolic pathways, including steady-state metal redox treatment mitochondrial activity of lipid, amino acid and glucose metabolism, and various signaling pathways associated with disease. Although the mechanisms of ferroptosis and cuproptosis are not yet fully understood, there is no doubt that ion overload plays a crucial act in these metal-dependent cell deaths. In this review, we discussed the core roles of ion overload in ferroptosis and cuproptosis, the association between metabolism imbalance and ferroptosis and cuproptosis, the extract the diseases caused by ion overload and current treatment modalities.

Design, synthesis, and biological evaluation of 2-amino-6-methyl-phenol derivatives targeting lipid peroxidation with potent anti-ferroptotic activities.

The suppression of ferroptosis is emerging as a promising therapeutic strategy for effectively treating a wide range of diseases, including neurodegenerative disorders, organ ischemia-reperfusion injury, and inflammatory conditions. However, the clinical utility of ferroptosis inhibitors is significantly impeded by the limited availability of rational drug designs. In our previous study, we successfully unraveled the efficacy of ferrostatin-1 (Fer-1) attributed to the synergistic effect of its ortho-diamine (-NH) moiety. In this study, we present the discovery of the ortho-hydroxyl-amino moiety as a novel scaffold for ferroptosis inhibitors, employing quantum chemistry as well as in vitro and in vivo assays. 2-amino-6-methylphenol derivatives demonstrated remarkable inhibition of RSL3-induced ferroptosis, exhibiting EC50 values ranging from 25 nM to 207 nM. These compounds do not appear to modulate iron homeostasis or lipid reactive oxygen species (ROS) generation pathways. Nevertheless, they effectively prevent the accumulation of lipid peroxides in living cells. Furthermore, compound 13 exhibits good in vivo activities as it effectively protect mice from kidney ischemia-reperfusion injury. In summary, compound 13 has been identified as a potent ferroptosis inhibitor, warranting further investigation as a promising lead compound.

Network pharmacology and in vitro experimental verification to reveal the mechanism of Astragaloside IV against kidney ischemia-reperfusion injury.

Ischemic acute kidney injury (AKI) is a prevalent disorder among hospitalized patients worldwide. Astragaloside IV (AS-IV) has been shown to protect against ischemic AKI. However, the specific effects and mechanisms of AS-IV on alleviating kidney ischemia-reperfusion (I/R) injury remain unclear. The objective of this research was to elucidate the regulatory targets and mechanisms through which AS-IV protects kidney I/R injury. A combination of network pharmacology, molecular docking, molecular dynamics (MD) simulation, pharmacodynamic study and Western blot were employed to explore the underlying mechanisms. Network pharmacology revealed that ferroptosis was a potential mechanism of AS-IV against kidney I/R injury. Molecular docking and MD simulations demonstrated strong binding affinity between the GPX4/SLC7A11 and AS-IV. The experimental verification demonstrated that AS-IV improved cell proliferation, decreased the level of ROS and Fe2+, and increased the expressions of GPX4 and SLC7A11 as same as Ferrostatin-1 in OGD/R-injured HUVECs. In conclusion, AS-IV had a significant inhibition on ferroptosis in kidney I/R injury, providing a new perspective for drug development on kidney I/R injury. Definitely, further exploration in vivo is necessary to fully understand whether AS-IV alleviates kidney I/R injury through inhibiting endothelial ferroptosis.

Alleviation of ischemia-reperfusion induced renal injury by chemically modified SOD2 mRNA delivered via lipid nanoparticles.

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, which is a serious clinical condition with no effective pharmacological treatment. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) significantly alleviate kidney IRI; however, the underlying mechanisms and key molecules conferring renoprotection remain elusive. In this study, we characterized the protein composition of MSC-EVs using a proteomics approach and found that mitochondrial protein superoxide dismutase 2 (SOD2) was enriched in MSC-EVs. Using lipid nanoparticles (LNP), we successfully delivered chemically modified SOD2 mRNA into kidney cells and mice with kidney IRI. We demonstrated that SOD2 mRNA-LNP treatment decreased cellular reactive oxygen species (ROS) in cultured cells and ameliorated renal damage in IRI mice, as indicated by reduced levels of serum creatinine and restored tissue integrity compared with the control mRNA-LNP-injected group. Thus, the modulation of mitochondrial ROS levels through SOD2 upregulation by SOD2 mRNA-LNP delivery could be a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Hexarelin alleviates apoptosis on ischemic acute kidney injury via MDM2/p53 pathway.

INTRODUCTION: Hexarelin exhibits significant protection against organ injury in models of ischemia/reperfusion (I/R)-induced injury (IRI). Nevertheless, the impact of Hexarelin on acute kidney injury (AKI) and its underlying mechanism remains unclear. In this study, we investigated the therapeutic potential of Hexarelin in I/R-induced AKI and elucidated its molecular mechanisms. METHODS: We assessed the protective effects of Hexarelin through both in vivo and in vitro experiments. In the I/R-induced AKI model, rats were pretreated with Hexarelin at 100 µg/kg/d for 7 days before being sacrificed 24 h post-IRI. Subsequently, kidney function, histology, and apoptosis were assessed. In vitro, hypoxia/reoxygenation (H/R)-induced HK-2 cell model was used to investigate the impact of Hexarelin on apoptosis in HK-2 cells. Then, we employed molecular docking using a pharmmapper server and autodock software to identify potential target proteins of Hexarelin. RESULTS: In this study, rats subjected to I/R developed severe kidney injury characterized by tubular necrosis, tubular dilatation, increased serum creatinine levels, and cell apoptosis. However, pretreatment with Hexarelin exhibited a protective effect by mitigating post-ischemic kidney pathological changes, improving renal function, and inhibiting apoptosis. This was achieved through the downregulation of conventional apoptosis-related genes, such as Caspase-3, Bax and Bad, and the upregulation of the anti-apoptotic protein Bcl-2. Consistent with the in vivo results, Hexarelin also reduced cell apoptosis in post-H/R HK-2 cells. Furthermore, our analysis using GSEA confirmed the essential role of the apoptosis pathway in I/R-induced AKI. Molecular docking revealed a strong binding affinity between Hexarelin and MDM2, suggesting the potential mechanism of Hexarelin's anti-apoptosis effect at least partially through its interaction with MDM2, a well-known negative regulator of apoptosis-related protein that of p53. To validate these findings, we evaluated the relative expression of MDM2 and p53 in I/R-induced AKI with or without Hexarelin pre-administration and observed a significant suppression of MDM2 and p53 by Hexarelin in both in vivo and in vitro experiments. CONCLUSION: Collectively, Hexarelin was identified as a promising medication in protecting apoptosis against I/R-induced AKI.

Calcitriol attenuates vascular remodeling in association with alteration of ppET-1/ETBR/eNOS and ETAR expression in acute and chronic phases of kidney ischemia-reperfusion injury in mice.

Kidney ischemia-reperfusion injury (IRI) causes acute kidney injury with increasing risk of maladaptive repair through endothelin-1 (ET-1)/endothelin type A receptor (ETAR) signaling. Calcitriol shows renoprotection in kidney fibrosis, however, its effects on vasoactive substances expression and vascular remodeling following kidney IRI remain unclear. This research aimed to investigate Calcitriol's effects on preproendothelin-1 (ppET-1), ETAR, endothelial nitric oxide synthase (eNOS) mRNA expression and vascular remodeling in acute and chronic phases of kidney IRI in mice. Twenty-five male Swiss mice were randomly divided into five groups (n = 5): SO (sham-operated), IR3 (3 day kidney IRI), IR12 (12 day kidney IRI), IRD3 (3 day kidney IRI + Calcitriol 0.5 µg/kg body weight (BW)/day), and IRD12 (12 day kidney IRI + Calcitriol 0.5 µg/kg BW/day). Ischemia-reperfusion injury groups underwent bilateral renal pedicles clamping for 30 min, then reperfusion. Kidneys were harvested for Sirius Red staining to observe interstitial fibrosis and vascular remodeling, polymerase chain reaction to quantify ppET-1, endothelin type B receptor (ETBR), eNOS mRNA expression, and Western blotting to quantify ETAR protein expression. Calcitriol treatment in both phases of kidney IRI showed lower serum creatinine and ETAR protein expression, while higher eNOS and ETBR mRNA expression than IRI-only groups. Furthermore, ppET-1 mRNA expression was higher in IRD3 than IR3, but lower in IRD12 than IR12. Calcitriol also prevented vascular remodeling as indicated by lower wall thickness and higher lumen/wall area ratio than IRI-only groups.

Does Ambroxol alleviate kidney ischemia-reperfusion injury in rats?

Objectives: Ischemia-reperfusion injury is a life-threatening clinical problem that can occur after transplantation or a number of clinical procedures. The purpose of the study was to investigate the effects of Ambroxol on kidney damage caused by experimentally induced ischemia-reperfusion injury in rats. Materials and Methods: Wistar albino rats were divided into 3 groups: Control (CTR, n=6), Kidney ischemia-reperfusion (K-IR, n=6), And kidney ischemia reperfusion+Ambroxol (K-IR+AMB, n=6). In K-IR+AMB group, Ambroxol (30 mg/kg) was administered orally 30 min before the ischemia period. K-IR and K-IR+AMB groups underwent 45 min of kidney ischemia followed by a 6-hour reperfusion period. At the end of the reperfusion period, blood and kidney tissue samples were collected after euthanasia. From the blood samples, BUN and creatinine levels were determined to assess kidney function, and TNF-α and IL-1ß concentrations were evaluated to determine inflammatory response. Results: While serum BUN, creatinine activities, and TNF-α and IL-1ß concentrations were higher in both IR groups compared with the CTR group, these values were found to be lower in the K-IR+AMB group compared with the K-IR group. Histopathological examination revealed that interstitial edema and desquamation of tubular cells in the K-IR group were more severe than in the K-IR+AMB group. Conclusion: Ambroxol treatment alleviated the production of pro-inflammatory cytokines and the harmful cellular effects in the tubular cells.

Inhibition of histone methyltransferase G9a effectively protected the kidney against ischemia-reperfusion injury.

This study examined whether BIX01294, a histone methyltransferase G9a inhibitor, effectively preserves the renal function following acute kidney ischemia-reperfusion (AKIR) injury. Adult-male-SD rats (n = 24) were equally categorized into Group 1 (sham-operated control), Group 2 (AKIR + 1.0 cc N/S I.P. injection), and Group 3 (AKIR + BIX01294/5 mg/Kg by I.P. administration at 3 h after the procedure) and the kidneys were harvested at day-3 post-IR procedure. The results showed that by day 3, the levels of creatinine and the blood urea nitrogen (BUN) were significantly higher in group 3 and more significantly higher in group 2 than in group 1 (all P < 0.0001). The protein expression of upstream (TLR-2/TLR-4/MyD88/TRAF6/p-NF-κB) and downstream (IL-1ß/IL-6/TNF-α) inflammatory signaling molecules exhibited a pattern identical to that of creatinine levels among the groups (all P < 0.0001). The protein expression of oxidative stress (NOX-1/NOX-2), MAP kinase family members (ASK1/MKK4/MKK7/JNK/p-38/p-ERK1/2), apoptosis (cleaved-caspase3/cleaved-caspase8/cleaved-PARP/mitochondrial-Bax), fibrosis (Smad3/TGF-ß), and mitochondrial-damaged markers (cyclophilin D/cytosolic-cytochrome-C) displayed a pattern identical to that of creatinine levels among the groups (all P < 0.0001). The kidney injury score, fibrosis, cellular expression of inflammation (CD68+cells), and glomerulus/renal-tubular damaged markers (Snail/KIM-1/WT-1) exhibited an identical pattern, whereas the cellular expression of podocyte component (synaptopodin) displayed an opposite pattern of creatinine levels among the groups (all P < 0.0001). Therefore, the G9a inhibitor effectively protected kidneys against IR injury.

Novel gold-platinum nanoparticles serve as broad-spectrum antioxidants for attenuating ischemia reperfusion injury of the kidney.

Kidney ischemia reperfusion injury (IRI) is a common and inevitable pathological condition in routine urological practices, especially during transplantation. Severe kidney IRI may even induce systemic damage to peripheral organs, and lead to multisystem organ failure. However, no standard clinical treatment option is currently available. It has been reported that kidney IRI is predominantly associated with abnormally increased endogenous reactive oxygen species (ROS). Scavenging excessive ROS may reduce the damage caused by oxidative stress and subsequently alleviate kidney IRI. Here, we reported a simple and efficient one-step synthesis of gold-platinum nanoparticles (AuPt NPs) with a gold core having a loose and branched outer platinum shell with superior ROS scavenging capacity to possibly treat kidney IRI. These AuPt NPs exhibited multiple enzyme-like anti-oxidative properties simultaneously possessing catalase- and peroxidase-like activity. These particles showed excellent cell protective capability, and alleviated kidney IRI both in vitro and in vivo without obvious toxicity, by suppressing cell apoptosis, inflammatory cytokine release, and inflammasome formation. Meanwhile, AuPt NPs also had an effect on inhibiting the transition to chronic kidney disease by reducing kidney fibrosis in the long term. Thus, AuPt NPs might be a good therapeutic agent for kidney IRI management and may be helpful for the development of clinical treatments for kidney IRI.

Combined levosimendan and Sacubitril/Valsartan markedly protected the heart and kidney against cardiorenal syndrome in rat.

BACKGROUND: Cardiorenal syndrome (CRS) remains the leading cause of death in hospitalized patients for all disease entities. Sacubitril/Valsartan (Sac/Val) therapy has been proved to improve prognostic outcome in patients with heart failure or chronic kidney disease. This study tested the hypothesis that combined levosimendan and Sac/Val was superior to just one therapy on protecting the heart and kidney against simultaneous heart and kidney ischemia (I) (for 50-min)-reperfusion (R) (for 7-days) (i.e., double IR) injury (defined as CRS). METHODS AND RESULTS: Adult-male Spraque-Dawley rats (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (double IR), group 3 [double IR+levosimendan (10 mg/kg by intra-peritoneum administration at 30 min/followed by days 1-5 once daily after IR procedure)], group 4 [double IR+Sac/Val (10 mg/kg, orally at 30 min/followed by days 1-5 twice daily after IR procedure)], and group 5 (double IR+Sac/Val+levosimendan). By day 7 after double-IR, the left-ventricular-ejection fraction (LVEF)/left-ventricular-fraction-shortening (LVFS) were highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but they showed no difference between groups 3/4, whereas the circulatory heart-failure (brain-natriuretic peptide)/proinflammatory (suppression of tumorigenicity-2) biomarkers, blood-urea-nitrogen/creatinine and ratio of urine protein to creatinine (all p < 0.0001) exhibited an opposite pattern of LVEF among the groups. The protein expressions of inflammatory (tumor necrosis factor-α/interleukin-1ß/matrix metalloproteinase-9)/oxidative-stress (NOX-1/NOX-2/NOX-4)/apoptotic (mitochondrial-Bax/caspase-3/poly-(ADP-ribose)-polymerase)/fibrotic (Smad3/transforming growth factor-ß)/mitochondrial-damaged (cytosolic-cytochrome-C)/myocardial-hypertrophic (ß-MHC) biomarkers in LV myocardium exhibited an opposite pattern of LVEF among the groups (all p < 0.0001). The cellular expressions of inflammatory (CD68)/DNA-damaged (γ-H2AX) biomarkers and infarct/fibrotic areas in LV myocardium and kidney displayed an opposite pattern of LVEF among the groups (all p < 0.0001). CONCLUSION: Combined levosimendan and Sac/Val was superior to merely one therapy on protecting the heart and kidney as well as preserving their functions against double IR injury.

Interferon-γ-Induced Myeloid-Derived Suppressor Cells Aggravate Kidney Ischemia-Reperfusion Injury by Regulating Innate Immune Cells.

OBJECTIVE: Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells which can suppress T-cell functionality. Herein, we evaluated the functional importance of MDSCs in the context of kidney ischemia-reperfusion injury (IRI) and explored their ability to regulate innate and adaptive immune cell function in this context. METHODS: The differentiation of MDSCs was induced in vitro by treating cells with GM-CSF and interferon (IFN)-γ. In a murine model of renal IRI, serum creatinine and blood urea nitrogen values were measured to monitor kidney function, while histopathological and immunohistochemical approaches were used to assess kidney injury severity. In addition, flow cytometry was employed to assess the phenotypes and apoptosis of kidney cells in these mice. RESULTS: MDSCs induced by treatment with GM-CSF + IFN-γ could suppress T-cell functionality in vitro. The adoptive transfer of these MDSCs into an IRI mouse model system enhanced kidney damage and impaired renal function following the recruitment of these cells to renal tissues in these mice. Following such adoptive transfer, the relative frequency of MDSCs with a CD11b+Ly6G-Ly6Chigh monocytic-MDSC phenotype decreased, whereas cells with a CD11b+Ly6G+Ly6Clow polymorphonuclear-MDSC phenotype become more prevalent within kidney tissues following IRI. Adoptive transfer also coincided with increased frequencies of macrophages and dendritic cells (DCs) in the kidney tissues. This suggested that M-MDSCs contributed to early-stage renal IRI damage by differentiating into these deleterious cell types. However, MDSC-induced suppression of CD4+ and CD8+ T-cell infiltration was not sufficient to prevent the deterioration of renal function in these mice. CONCLUSIONS: Herein, we successfully developed a protocol wherein MDSCs were differentiated in vitro through combination GM-CSF/IFN-γ treatment. When these MDSCs were subsequently adoptively transferred into a murine model of renal IRI, they aggravated kidney damage, likely owing to the differentiation of M-MDSCs into deleterious macrophages and DCs.

A ketogenic diet attenuates acute and chronic ischemic kidney injury and reduces markers of oxidative stress and inflammation.

BACKGROUND: Ischemic kidney injury is a common clinical condition resulting from transient interruption of the kidney's normal blood flow, leading to oxidative stress, inflammation, and kidney dysfunction. The ketogenic diet (KD), a low-carbohydrate, high-fat diet that stimulates endogenous ketone body production, has potent antioxidant and anti-inflammatory effects in distinct tissues and might thus protect the kidney against ischemia and reperfusion (IR) injury. MAIN METHODS: Male Wistar rats were fed a KD or a control diet (CD) for three days before analyzing metabolic parameters or testing nephroprotection. We used two different models of kidney IR injury and conducted biochemical, histological, and Western blot analyses at 24 h and two weeks after surgery. KEY FINDINGS: Acute KD feeding caused protein acetylation, liver AMPK activation, and increased resistance to IR-induced kidney injury. At 24 h after IR, rats on KD presented reduced tubular damage and improved kidney functioning compared to rats fed with a CD. KD attenuated oxidative damage (protein nitration, 4-HNE adducts, and 8-OHdG), increased antioxidant defenses (GPx and SOD activity), and reduced inflammatory intermediates (IL6, TNFα, MCP1), p50 NF-κB expression, and cellular infiltration. Also, KD prevented interstitial fibrosis development at two weeks, up-regulation of HSP70, and chronic Klotho deficiency. SIGNIFICANCE: Our findings demonstrate for the first time that short-term KD increases tolerance to experimental kidney ischemia, opening the opportunity for future therapeutic exploration of a dietary preconditioning strategy to convey kidney protection in the clinic.

miR-17-5p attenuates kidney ischemia-reperfusion injury by inhibiting the PTEN and BIM pathways.

BACKGROUND: Kidney ischemia-reperfusion (I/R) injury is an independent risk factor for delayed graft function after kidney transplantation with long-term graft survival deterioration. Previously, we found that the upregulated expression of miR-17-5p exerts a protective effect in kidney I/R injury, but the mechanism has not been clearly studied. METHODS: A kidney I/R injury model was induced in adult C57BL/6 male mice (20-22 g) by clamping both kidney pedicles for 30 min. The miR-17-5p agomir complex was injected into mice 24 h before surgery via the tail vein at a total injection volume of 10 µL/g body weight. The mice were euthanized on post-I/R injury day 2, and kidney function, apoptosis, autophagy, and related molecules were then detected. Human kidney-2 (HK-2) cells, which underwent hypoxia/reoxygenation, were treated with the miR-17-5p agomir, miR-17-5p antagomir, and small interfering ribonucleic acids (siRNAs). Cell viability, apoptosis, autophagy, and molecules were also examined. RESULTS: Autophagy, miR-17-5p expression, and kidney function damage were significantly more increased in the I/R group than in the sham group. In the cultured HK-2 cells underwent hypoxia/reoxygenation, the miR-17-5p agomir directly inhibited the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Bcl-2 like protein 11 (BIM), and attenuated apoptosis and autophagy. Further, miR-17-5p inhibited autophagy by activating the protein kinase B (Akt)/Beclin1 pathway, which was suppressed by siRNAs. Additionally, the administration of miR-17-5p agomir greatly improved kidney function in the I/R mice group by inhibiting autophagy and apoptosis. CONCLUSIONS: These findings suggest a new possible therapeutic strategy for the prevention and treatment of kidney I/R injury. The upregulation of miR-17-5p expression appears to inhibit apoptosis and autophagy by suppressing PTEN and BIM expression, which in turn upregulates downstream Akt/Beclin1 expression.

The Protective Role of Prolyl Oligopeptidase (POP) Inhibition in Kidney Injury Induced by Renal Ischemia-Reperfusion.

Ischemia/reperfusion injury (IRI) is a complex pathophysiological process characterized by blood circulation disorder caused by various factors, such as traumatic shock, surgery, organ transplantation, and thrombus. Severe metabolic dysregulation and tissue structure destruction are observed upon restoration of blood flow to the ischemic tissue. The kidney is a highly perfused organ, sensitive to ischemia and reperfusion injury, and the incidence of renal IRI has high morbidity and mortality. Several studies showed that infiltration of inflammatory cells, apoptosis, and angiogenesis are important mechanisms involved in renal IRI. Despite advances in research, effective therapies for renal IRI are lacking. Recently it has been demonstrated the role of KYP2047, a selective inhibitor of prolyl oligopeptidase (POP), in the regulation of inflammation, apoptosis, and angiogenesis. Thus, this research focused on the role of POP in kidney ischemia/reperfusion (KI/R). An in vivo model of KI/R was performed and mice were subjected to KYP2047 treatment (intraperitoneal, 0.5, 1 and 5 mg/kg). Histological analysis, Masson's trichrome and periodic acid shift (PAS) staining, immunohistochemical and Western blots analysis, real-time PCR (RT-PCR) and ELISA were performed on kidney samples. Moreover, serum creatinine and blood urea nitrogen (BUN) were quantified. POP-inhibition by KYP2047 treatment, only at the doses of 1 and 5 mg/kg, significantly reduced renal injury and collagen amount, regulated inflammation through canonical and non-canonical NF-κB pathway, and restored renal function. Moreover, KYP2047 modulated angiogenesis markers, such as TGF-ß and VEGF, also slowing down apoptosis. Interestingly, treatment with KYP2047 modulated PP2A activity. Thus, these findings clarified the role of POP inhibition in AKI, also offering novel therapeutic target for renal injury after KI/R.

Combined tacrolimus and melatonin effectively protected kidney against acute ischemia-reperfusion injury.

Acute kidney injury (AKI) is commonly encountered and causes high mortality in hospitalized patients; however, effective therapies for AKI have still not been established. Accordingly, we performed a rodent model with acute renal ischemia-reperfusion (IR) and tested the hypothesis that combined tacrolimus and melatonin therapy could be superior to either one for protecting the kidney against IR injury. Adult-male SD rat (n = 30) were equally categorized into group 1 (receiving laparotomy only), group 2 (IR treated by 3.0 cc/normal-saline), group 3 [IR + tacrolimus/0.5 mg/kg by intravenous administration at 30 minutes and at days 1/2/3 after IR], group 4 (IR + melatonin/50 mg/kg by intra-peritoneal administration at 30 minutes and 25 mg/kg at days 1/2/3 after IR] and group 5 (IR + tacrolimus +melatonin). By day 3 after IR, the creatinine/BUN levels and ratio of urine protein to urine creatinine were highest in group 2, lowest in group 1 and significantly lower in group 5 than in groups 3/4 (all P < .0001), but they did not differ between the groups 3/4. The protein expressions of oxidative-stress (p47phox/NOX-1/NOX-2/NOX-4), upstream (TLR4/MAL/MyD88/TRAF6/ASK1/MKK4/MKK7/NF-κB) and downstream (IL-6/INF-γ/MMP-9/IL-1ß) inflammatory signaling, MAPK-family-signaling cascades(ERK1/2, JNK/p38/c-JUN), apoptotic/autophagic (p53/caspase 3/mitochondrial-Bax, ratio of LC3B-II/LC3B-I), and mitochondrial-damaged (cyclophilin D/cytochrome C/DRP1) biomarkers, and the expressions of inflammatory-immune cells (F4/80, CD14/CD3/CD8) as well as the kidney injured score exhibited an identical pattern of creatinine level (all P < .0001). In conclusion, combined tacrolimus and melatonin therapy was better than either single one on protecting the kidney functional and anatomical integrity against IR injury through suppressing inflammation and the generation of oxidative stress.

[Synergism of carbamylated darbepoetin and L-ethoxidol in the model of experimental kidney ischemia].

AIM: to determine the efficiency of different doses of erythropoietin and carbamylated darbepoetin, to prove experimentally the possibility of increasing the efficiency of carbamylated darbepoetin when using the levorotatory stereoisomer of ethoxidol. MATERIALS AND METHODS: On the model of ischemia-reperfusion injury in male CD-1 mice that were undergone to contralateral nephrectomy, the nephroprotective effect of different doses of erythropoietin alfa, carbamylated darbepoetin, L-ethoxidol (the levorotatory enantiomer of ethylmethylhydroxypyridine malate), and the combined use of L-ethapylated carboxypyridine malate and L-etapoietin alfa was studied. The parameters of microcirculation and glomerular filtration rate were studied one day after 30-minute ischemia. RESULTS: It has been established that the prophylactic use of erythropoietin alfa and carbamylated darbepoetin in the model of ischemia-reperfusion injury of a single kidney reduces the severity of microcirculatory impairment and ensures the preservation of the glomerular filtration rate in dose-dependent manner. The synergistic effect of L-ethoxidol and carbamylated darbepoetin was found when these substances were used together. CONCLUSION: Prevention of ischemia-reperfusion kidney injury by analogs of human erythropoietin and their combination with ethylmethylhydroxypyridine derivatives is experimentally-proved.

Kidney Ischemia/Reperfusion Injury Induces Changes in the Drug Transporter Expression at the Blood-Brain Barrier in vivo and in vitro.

Ischemia/reperfusion injury is a major cause of acute kidney injury (AKI). AKI is characterized by a sudden decrease in kidney function, systemic inflammation, oxidative stress, and dysregulation of the sodium, potassium, and water channels. While AKI leads to uremic encephalopathy, epidemiological studies have shown that AKI is associated with a subsequent risk for developing stroke and dementia. To get more insights into kidney-brain crosstalk, we have created an in vitro co-culture model based on human kidney cells of the proximal tubule (HK-2) and brain microvascular endothelial cells (BMEC). The HK-2 cell line was grown to confluence on 6-well plates and exposed to oxygen/glucose deprivation (OGD) for 4 h. Control HK-2 cells were grown under normal conditions. The BMEC cell line cerebED was grown to confluence on transwells with 0.4 µm pores. The transwell filters seeded and grown to confluence with cereEND were inserted into the plates with HK-2 cells with or without OGD treatment. In addition, cerebEND were left untreated or treated with uremic toxins, indole-3-acetic acid (IAA) and indoxyl sulfate (IS). The protein and mRNA expression of selected BBB-typical influx transporters, efflux transporters, cellular receptors, and tight junction proteins was measured in BMECs. To validate this in vitro model of kidney-brain interaction, we isolated brain capillaries from mice exposed to bilateral renal ischemia (30 min)/reperfusion injury (24 h) and measured mRNA and protein expression as described above. Both in vitro and in vivo systems showed similar changes in the expression of drug transporters, cellular receptors, and tight junction proteins. Efflux pumps, in particular Abcb1b, Abcc1, and Abcg2, have shown increased expression in our model. Thus, our in vitro co-culture system can be used to study the cellular mechanism of kidney and brain crosstalk in renal ischemia/reperfusion injury.

Evodiamine alleviates kidney ischemia reperfusion injury in rats: A biochemical and histopathological study.

Renal ischemia/reperfusion (I/R) injury resulting in acute renal failure, is a major clinical problem due to its high mortality rate. Renal I/R increases the reactive oxygen species, secretion of inflammatory cytokines, chemokines and other factors. This suggests that initiating the apoptosis process in the presence of oxidative stress may play a role in life-threatening conditions, such as ischemia. Ischemia reperfusion-induced renal damage can result in renal failure and death. Although many treatment procedures have been carried out to reduce or destroy renal I/R damage in experimental models, so far, a routine method of treatment has not yet been found. For this reason, the current study was planned to investigate the possible protective effects of evodiamine on tissue damage caused by ischemia-reperfusion in kidney tissue in rats and an experimental renal I/R model was used for this purpose. Four groups were formed in the study: the control, sham control, ischemia reperfusion (I/R), and evodiamine (10 mg/kg) + I/R groups. The effects of evodiamine against kidney I/R injury were investigated. TAS (total oxidant status), TOS (total oxidant status), interleukin-1ß (IL-1ß), IL-6, IL-10 and tumor necrosis factor-α levels were determined by enzyme-linked immunosorbent assay. The oxidative stress index was calculated from TAS and TOS levels. In addition, the renal ischemia reperfusion injury was examined histopathologically. The IL-10 and TAS levels in the I/R group decreased when compared with the control and Sham groups, while these levels increased in the evodiamine group. Histopathologic examination revealed that caspase 3 and nuclear factor-κB levels decreased in the evodiamine group compared with the I/R group. The application of evodiamine significantly reduced ischemia reperfusion-induced kidney damage due to its antioxidant, anti-inflammatory and antiapoptotic properties.