Renal Repair Research Articles

P0518VNN1 MEDIATES RENAL MALADAPTIVE REPAIR AFTER AKI BY INDUCING PREMATURE SENESCENCE OF RENAL TUBUAR CELLS

Abstract Background and Aims Renal maladaptive repair after acute kidney injury (AKI) can easily progress to chronic kidney disease. Sustained renal interstitial damage caused by accelerated senescence of renal tubular cells leads to renal fibrosis. Vanin-1 (VNN1) is an extracellular enzyme with panthenylmethylaminease activity that indirectly reduces the synthesis of glutathione, causing oxidative stress. The purpose of this study was to investigate the expression and of VNN1 in renal tissue and to study its role in senescence of renal tubular cells after ischemia reperfusion (I/R). Method hirty male wild BALB/c mice were randomly divided into control group, sham group and I/R group. In the I/R group, the bilateral renal pedicle was ligatured for 35 min followed by reperfusion. The expression of VNN1 and aging markers (P16, P21, SA-b-gal) were detected. Furthermore, wild type mice and VNN1 knockout mice were used to compare the degree of renal tissue and functional damage and the senescence of renal tubular cells after I/R injury. Results Compared with sham group, Scr, BUN and renal injury score increased significantly in I/R group at the early stage (3d) of renal injury. Renal fibrosis was observed in the later stage (28-42d). The expression of VNN1 in renal tubular cells of I/R group increased after I/R injury. VNN1 was coexpressed with P16, suggesting that VNN1 might be related to cellular stress senescence. The SCr, BUN of VNN1 KO mice was significantly lower than that of wild type mice at 7-28 d after renal reperfusion. The renal interstitial injury score of VNN1 KO mice was significantly lower than that of wild type mice, and the renal interstitial fibrosis level was significantly higher than that of wild type mice at 42d after reperfusion. The results suggest that VNN1 KO promotes renal repair of AKI. The ratio of P16 positive tubule cells in VNN1 KO mice was significantly higher than that in wild-type mice at 7d after renal reperfusion, suggesting that VNN1 could promote the senescence of renal tubule cells during AKI repair. Conclusion VNN1 mediates renal maladaptive repair after AKI by inducing premature senescence of renal tubular cells.

P0524PERICYTE IS ESSENTIAL FOR RENAL TUBULAR CELL REGENERATION AFTER ACUTE KIDNEY INJURY

Abstract Background and Aims Pericyte-myofibroblast transition is activated after acute kidney injury (AKI) and is the major mechanism of ensuing chronic kidney disease (CKD). Nevertheless, the role of pericyte in renal regeneration after AKI has not been deeply investigated. Many studies have shown that pericyte can secret growth factors such as fibroblast growth factor 1 and 7 (FGF-1, FGF-7) and is essential for structure support and vascular integrity in normal kidney. We supposed that the ablation or inhibition of pericytes during AKI would retard renal repair. Method Our study demonstrated that activated pericytes/myofibroblast was beneficial for renal regeneration after AKI. We here performed pericyte ablation and pericyte inhibition after ischemia-reperfusion renal injury by using transgenic mice such as Gli1-CreERT2;iDTR mice and blockade of platelet-derived growth factor receptor β (PDGFRβ), respectively. Results Renal injury was more severe and renal recovery was worse in groups of pericyte ablation or inhibition compared to control groups. Ki67 positive tubular cells which indicated renal regeneration were much more in control groups than that in groups of pericyte ablation or inhibition. We also found higher macrophage number as well as higher inflammatory factor including tumor necrosis factor-α and interleukin-1β which indicated more severe inflammation in groups of pericyte ablation or inhibition. Conclusion These studies suggest that pericytes play a beneficial role during renal recovery after AKI. These findings delineate the adequate timing when we target on pericyte/myofibroblast to ameliorate renal fibrosis and avoid to impede renal regeneration at the same time. Further research is still needed to clarify the change of specific gene and signalling pathway after pericyte ablation or inhibition. These are promising findings that provide opportunities to develop new targets to promote AKI recovery and to ameliorate renal fibrosis.

P0390THERAPEUTIC EFFECTS AND SERUM METABOLOMIC VARIATIONS IN FOCAL SEGMENTAL GLOMERULOSCLEROSIS MICE ON TREATMENT WITH HUMAN UMBILICAL MESENCHYMAL STEM CELLS

Abstract Background and Aims Focal segmental glomerulosclerosis (FSGS) mediates the kidney podocyte dysfunction and leads to chronic renal diseases worldwide. Current treatment options are limited, owing to the poor understanding of the metabolic pathologic variations and regeneration of FSGS. Mesenchymal stem cells (MSC) offer the better insights to prevent renal injury and could promote the recovery of renal structure and function through complex mechanisms. Due to the safe, feasible, and therapeutic features, we first designed to investigate the role of human umbilical mesenchymal stem cells (HUMSCs) on FSGS mice and explored the potential serum metabolomic variations. Method Nephropathy was induced by adriamycin (ADR) in male Balb/C mice to study FSGS via intravenous administration. 2*106 HUMSCs are provided to treat FSGS model for 3 times. Renal function was measured by urine protein, serum urea nitrogen (BUN) and serum creatinine (SCr) in the study. Serum metabolic profiles from three groups of Balb/C mice were analysed using ultra- performance liquid chromatography coupled with a triple quadrupole-linear ion trap mass spectrometer and a novel mass spectrometry (UPLC-MS/MS) data collection technique. Results The concentrations of SCr and BUN were apparently decreased after HUMSCs injection for three times compared with the FSGS model and body weight from HUMSCs group was improved significantly. A total of 532 differential metabolites were identified between FSGS group and the normal control group. Bile acid dysregulation and valine/leucine/ isoleucine metabolism pathway, especially, N-acetylvaline and L-valine, were positively associated to ADR-induced FSGS. A panel of identified specific metabolites (pyrrole-2- carboxylic acid, urocanic acid and 6-hydroxynicotinic acid) as well as valine/leucine/isoleucine metabolism pathway rather than bile acid metabolism were related to the renal repair after HUMSCs treatment. Conclusion The administration of HUMSCs in FSGS induced ADR provides the promising protection owing to the improvement of metabolomics. Figure 2. The distribution of DiR-HUMSCs in vivo. Figure 3. Kidney pathology using periodic acid-Schiff (PAS) and Masson staining. Figure 4. Metabolome profiling analysis and Venn diagram for comparisons of numbers from each group. Figure 5. Metabolic pathway analysis results from FSGS + Saline and FSGS + HUMSCs groups. Figure S1. The quality control (QC) of serum metabolomics was designed and performed as follows. Figure S2. Metabolic pathway analysis results from FSGS + Saline and Normal + Saline groups. Figure S3. Metabolic pathway analysis results from FSGS + HUMSCs and Normal + Saline groups.

Distal Renal Artery Aneurysm Repair: “More than Meets the Eye”

Distal Renal Artery Aneurysm Repair: “More than Meets the Eye”

Exosomes derived from hucMSC attenuate renal fibrosis through CK1\u03b4/\u03b2-TRCP-mediated YAP degradation

Exosomes from human umbilical cord mesenchymal stem cells (hucMSC-Ex) have been suggested as novel nanomaterials for regenerative medicine. Here we explored the roles of hucMSC-Ex through regulating Yes-associated protein (YAP) in renal injury repair by using rat unilateral ureteral obstruction (UUO) models. Our study identified mechanical stress induced YAP nucleus expression and stimulated collagen deposition and interstitial fibrosis in the kidney. Then, infusion with hucMSC-Ex promoted YAP nuclear cytoplasmic shuttling and ameliorated renal fibrosis in UUO model. Interestingly, hucMSC-Ex delivered casein kinase 1δ (CK1δ) and E3 ubiquitin ligase β-TRCP to boost YAP ubiquitination and degradation. Knockdown of CK1δ and β-TRCP in hucMSC decreased the repairing effects of hucMSC-Ex on renal fibrosis. Our results suggest that hucMSC-Ex attenuates renal fibrosis through CK1δ/β-TRCP inhibited YAP activity, unveiling a new mechanism for the therapeutic effects of hucMSC-Ex on tissue injury and offering a potential approach for renal fibrosis treatment.

Stimulation of 5‐HT1F Receptor Increases Vascular Recovery Following Ischemia/Reperfusion‐Induced AKI

Acute kidney injury (AKI) is a disease with no treatment. After AKI, there is a marked reduction in renal vasculature. Thus, promoting vascular recovery following AKI could facilitate renal repair as the vasculature is responsible for carrying oxygen and nutrients to extravascular tissues. Our laboratory has shown that stimulating mitochondrial biogenesis (MB) through the 5‐HT1F receptor stimulates recovery from AKI and 5‐HT1F receptor knockout mice have decreased MB and poor renal recovery. Importantly, we have shown that stimulation of the 5‐HT1F receptor with LY344864 or lasmiditan induces MB, branching morphogenesis, and migration in human renal glomerular endothelial cells (EC) in vitro. We hypothesize that the 5‐HT1F receptor plays a role in renal vascular recovery following AKI. 5‐HT1F receptor KO mice have decreased CD31+ and aSMA+ ECs in the kidney, suggesting that the 5‐HT1F receptor plays a role in renal vascular homeostasis. To assess the role of the 5‐HT1F receptor in renal vascular injury, WT and 5‐HT1F receptor KO mice were subjected to IR‐induced AKI. 5‐HT1F receptor KO mice exhibited increased renal Evans blue dye (EBD) extravasation in comparison to I/R injured WT mice 24h following injury, suggesting increased vascular injury. To assess the role of 5‐HT1F receptor in renal vascular recovery following IR‐induced AKI, WT mice were treated with LY344864 (2 mg/kg) beginning 24h after I/R‐induced AKI. LY344864 decreased renal EBD extravasation 144h following injury compared to vehicle treated AKI mice, suggesting that stimulation of 5‐HT1F receptor increases vascular recovery. We also assessed whether or not lasmiditan, a more specific and potent 5‐HT1F receptor agonist which has recently been FDA approved, would induce MB in vivo. Mice were treated with lasmiditan (0.3 mg/kg) for 24h had increased protein levels of PGC1a and TFAM, both of which are regulators of MB and markers of MB. Taken together, these data indicate a role for 5‐HT1F receptor signaling in renal vascular injury and repair following I/R‐induced AKI. We propose that inducing MB in ECs after AKI restores vascular function and stimulates renal repair and recovery, and that repurposing lasmiditan as a treatment option for AKI may prove useful.Support or Funding InformationThis work was supported by F32 DK120222‐01A1 to TVD (National Institute of Health) and 1BX000851 (Department of Veterans Affairs) to RGS.

Co‐Delivery of Anti‐Inflammatory and Proliferative Agents by Injectable Hydrogel to Promote Tissue Repair after Acute Kidney Injury

ObjectIschemia‐reperfusion (I/R)‐induced acute renal injury has become a serious issue in clinical. The increasingly mortality, induced by chronic fibrosis and further renal dysfunction which caused by poor recovery of acute injury, has made it urgent to address kidney tissue repair. By using a renal I/R injury model, we aimed to investigate the role of a hydrogel‐based dual‐drug delivery platform on promoting tissue repair.MethodsAn injectable, self‐assembling peptide/heparin (SAP/Hep) hydrogel was employed to co‐deliver TNF‐α neutralizing antibody (anti‐TNF‐α) and hepatocyte growth factor (HGF). We analyzed the microstructure and controlled release properties of KLD2R/Hep hydrogel in vivo. The effects of the drug‐loaded hydrogel (SAP‐drug) on renal injury were evaluated in a rodent renal I/R injury model.ResultsIn vitro, the SAP/Hep hydrogel exhibited a faster release of anti‐TNF‐α with a sustained release of HGF, and both drugs could maintain better bioactivities after release. In vivo, combined anti‐TNF‐α/HGF showed better renal protective potential than anti‐TNF‐α or HGF alone. Compared with free‐drug (anti‐TNF‐α/HGF in solution) or SAP alone , SAP‐drug treatment significantly reduced the levels of serum creatinine (Scr)/blood urea nitrogen (BUN), tubular apoptosis, renal inflammatory factors and macrophage infiltration. Moreover, the SAP‐drug group exhibited better efficacy on promoting tubular cell proliferation and dedifferentiation than SAP or free‐drug alone, and thus reduced chronic renal fibrosis in I/R injury mice.ConclusionsWe confirmed that SAP could sequentially deliver anti‐TNF‐α and HGF to achieve anti‐inflammatory and pro‐proliferative effects simultaneously with only once injection, and thus can be a promising delivery platform for tissue repair.Support or Funding InformationThis work was supported by grants from National Natural Science Foundation of China (81571808, 31871001, 31200754) and Sichuan Science and Technology Program (2019YJ0069)Design of dual‐drug delivery KLD2R/Hep hydrogel for enhancing renal repair. The formation of the cationic KLD2R/anionic heparin hybrid hydrogel via electrostatic interaction, and heparin further had high affinity to HGF. The encapsulated anti‐TNF‐α and HGF were released from hydrogel in a sequential manner, and thus synergistically promoted tissue repair.Figure 1

Mesenchymal Stem Cell-Derived Extracellular Vesicles Induce Regulatory T Cells to Ameliorate Chronic Kidney Injury.

Metabolic syndrome (MetS) profoundly changes the contents of mesenchymal stem cells and mesenchymal stem cells-derived extracellular vesicles (EVs). The anti-inflammatory TGF-β (transforming growth factor-β) is selectively enriched in EVs from Lean but not from MetS pigs, but the functional impact of this endowment remains unknown. We hypothesized that Lean-EVs more effectively induce regulatory T cells in injured kidneys. Five groups of pigs (n=7 each) were studied after 16 weeks of diet-induced MetS and unilateral renal artery stenosis (RAS; MetS+RAS). Two groups of MetS+RAS were treated 4 weeks earlier with an intrarenal injection of either Lean-EVs or MetS-EVs. MetS+RAS had lower renal volume, renal blood flow, and glomerular filtration rate than MetS pigs. Compared with Lean-EVs, MetS-EVs were less effective in improving renal function and decreasing tubular injury and fibrosis in MetS+RAS. Lean-EVs upregulated TGF-β expression in stenotic kidney and increased regulatory T cells numbers more prominently. Furthermore, markedly upregulated anti-inflammatory M2 macrophages reduced proinflammatory M1 macrophages, and CD8+ T cells were detected in stenotic kidneys treated with Lean-EVs compared with MetS-EVs, and renal vein levels of interleukin-1β were reduced. In vitro, coculture of Lean-EVs with activated T cells led to greater TGF-β-dependent regulatory T cells induction than did MetS-EVs. Therefore, the beneficial effects of mesenchymal stem cells-derived EVs on injured kidneys might be partly mediated by their content of TGF-β signaling components, which permitting increased Treg preponderance. Modulating EV cargo and transforming their functionality might be useful for renal repair.

Reduced Albuminuria and Potassemia Indicate Early Renal Repair Processes after Resynchronization Therapy in Cardiorenal Syndrome Type 2.

Background Patients with chronic cardiorenal syndrome type 2 (T2-CRS) who qualify for resynchronization therapy (CRT) are exposed perioperatively to potentially nephrotoxic factors including contrast agents and blood loss. Methods The objective of this prospective interventional study was to assess the effects of CRT on renal function in patients with T2-CRS within the first 48 hours following implantation. Initially, 76 patients (15% female; aged 69 ± 9.56 years) with heart failure (New York Heart Association classes II–IV), ejection fraction ≤ 35%, and QRS > 130 ms were included in the study. During CRT implantation, a nonionic contrast agent (72.2 ± 44.9 mL) was administered. Prior to and 48 hours following implantation, renal function was evaluated using the following serum biomarkers: creatinine (sCr), estimated glomerular filtration rate (using the Chronic Kidney Disease Epidemiology Collaboration equation [eGFRCKD-EPI]), and the electrolyte and urine biomarkers albumin (uAlb), albumin/creatinine ratio (UACR), and neutrophil gelatinase-associated lipocalin (uNGAL). Results Before CRT, patients classified as NYHA class III or IV had higher uNGAL levels in comparison to uNGAL levels after CRT (43.63 ± 60.02 versus 16.63 ± 18.19; p=0.041). After CRT implantation, uAlb, UACR, and potassium levels were reduced (p < 0.05), and uNGAL, sCr, and eGFRCKD-EPI were unchanged. The contrast medium volume did not correlate with the test biomarkers (p > 0.05). Conclusions In patients with T2-CRS, uNGAL is a biomarker of kidney injury that correlates with the NYHA classes. A stable uNGAL value before and after CRT implantation confirms the lack of risk of contrast-induced nephropathy. Reduced albuminuria and blood potassium are biomarkers of improving T2-CRS in the early post-CRT period.

Trib1 Contributes to Recovery From Ischemia/Reperfusion-Induced Acute Kidney Injury by Regulating the Polarization of Renal Macrophages.

Increasing evidence suggests that macrophage polarization is involved in the recovery from ischemia-reperfusion (I/R)-induced acute kidney injury (AKI), implying that the regulation of macrophage polarization homeostasis might mediate AKI recovery. Trib1 is a key regulator of macrophage differentiation, but its role in AKI remains unclear. Here, we aimed to investigate the role of Trib1 and its link with the macrophage phenotype in the process of adaptive recovery from I/R-induced renal injury. Lentiviral vector-mediated RNA interference (RNAi) was used to knock down Trib1 expression in vitro and in vivo, and a mouse model of moderate AKI was established by the induction of I/R injury. Renal function measurements and inflammatory factors were determined by the corresponding kits. Histomorphology was assessed by hematoxylin-eosin, Masson and PAS staining. Western blot and flow cytometry were employed for the analysis of signal transduction, cell apoptosis and macrophage phenotypes. Trib1 knockdown inhibited cell viability of tubular epithelial cells (TECs) by inhibiting proliferation and enhancing apoptosis in vitro. I/R-induced AKI significantly impaired renal function in mice via increasing the levels of BUN, Scr, NGAL and renal tubular damage, leading to renal fibrosis from days 1 to 3. Through the adaptive self-repair mechanism, renal dysfunction recovered over time and returned to almost normal levels on day 28 after I/R intervention. However, Trib1 depletion worsened renal damage on day 3 and blunted the adaptive repair process of the renal tissue. Mechanistically, Trib1 inhibition suppressed renal tubular cell proliferation under adaptive self-repair conditions by affecting the expression of the proliferation-related proteins cyclin D1, cyclin B, p21, and p27, the apoptosis-related proteins Bcl-2 and Bax, and the fibrosis-related proteins collagen I and III. Furthermore, the M1/M2 macrophage ratio increased in the first 3 days and decreased from day 7 to day 28, consistent with changes in the expression of inflammatory factors, including TNFα, IL-6, IL-12, IL-10, and IL-13. Trib1 inhibition blocked macrophage polarization during adaptive recovery from I/R-induced moderate AKI. Our results show that Trib1 plays a role in kidney recovery and regeneration via the regulation of renal tubular cell proliferation by affecting macrophage polarization. Thus, Trib1 might be a viable therapeutic target to improve renal adaptive repair following I/R injury.

7-Hydroxycoumarin protects against cisplatin-induced acute kidney injury by inhibiting necroptosis and promoting Sox9-mediated tubular epithelial cell proliferation

Background7-Hydroxycoumarin (7-HC), also known as umbelliferon, is commonly found in Chinese herbs (e.g. Eucommiae Cortex, Prunellae Spica, Radix Angelicae Biseratae). Previous laboratory studies have indicated that 7-HC has anti-inflammatory, anti-oxidative, and anti-tumor effects. Cisplatin is a widely used chemotherapeutic agent for cancer. Nephrotoxicity is one of the limiting side effects of cisplatin use. PurposeThis study aimed to evaluate the renoprotective effect of 7-HC in a cisplatin-induced acute kidney injury (AKI) mouse model. MethodsAKI was induced in male C57BL/6 mice (aged 6–8 weeks) by a single intraperitoneal injection of cisplatin at 20 mg/kg. The mice received 7-HC at 30, 60, and 90 mg/kg intraperitoneally before or after cisplatin administration. Renal function, necroptosis, and cell proliferation were measured. Mechanisms underlying the reno-protective effect of 7-HC were explored in renal tubular epithelial cells treated with or without cisplatin. ResultsIn-vivo experiments showed that 7-HC significantly improved the loss in kidney function induced by cisplatin, as indicated by lower levels of serum creatinine and blood urea nitrogen, in AKI mice. Consistent herewith, cisplatin-induced tubular damage was alleviated by 7-HC as shown by morphological (periodic acid–Schiff staining) and kidney injury marker (KIM-1) analyses. We found that 7-HC suppressed renal necroptosis via the RIPK1/RIPK3/MLKL pathway and accelerated renal repair as evidenced by the upregulation of cyclin D1 in cisplatin-induced nephropathy. In-vitro experiments showed that knockdown of Sox9 attenuated the suppressive effect of 7-HC on KIM-1 and reversed the stimulatory effect of 7-HC on cyclin D1 expression in cisplatin-treated HK-2 cells, indicating that 7-HC may protect against AKI via a Sox9-dependent mechanism. Conclusion7-HC inhibits cisplatin-induced AKI by suppressing RIPK1/RIPK3/MLKL-mediated necroptosis and promoting Sox9-mediated tubular epithelial cell proliferation. 7-HC may serve as a preventive and therapeutic agent for AKI.

Post traumatic ureteral defect brigded with ileal segment (Yang-Monti) for inferior ureterocalycostomy: a rare case report with review of literature

Ureteric substitution using the Yang-Monti principle was reported as a modification of simple ileal ureter replacement. A patient underwent ileal ureteral substitution using a reconfigured ileal segment of Yang-Monti principle in our clinical centre. Authors report a case of a 41year old male involved in a homicidal stab injury with isolated renal pelvis injury underwent Thompson’s renal capsular flap repair. After 6 weeks, double J (DJ) stent was removed and following that patient developed urinoma. Percutaneous drain was placed to drain urinoma on emergency basis and again 6 Fr DJ stent was inserted but patient had recurrent fever and chills. On CECT evaluation authors noticed that DJ stent was outside the upper urinary tract. And then patient was re-explored where authors found 6 cm stricture of the proximal left ureter. A reconfigured small bowel tube was interposed between inferior calyx and proximal ureteral stumps. This technique offers certain distinct advantages. A short ileal segment is included with the consequent absence of metabolic complications. Yang-Monti Principle is a safer and efficient technique for clinical partial and complete ureteral defects with sustained, good, long-term results. Yang-Monti reconfigured tube seems to be promoted an equally efficient urine transport mechanism that persists unaltered for long periods if patients and potential risks could be well prepared.

Ablation of Gsa impairs renal tubule proliferation after injury via CDK2/cyclin E.

Acute kidney injury has a high global morbidity associated with an increased risk of death and chronic kidney disease. Renal tubular epithelial cell regeneration following injury may be a decisive factor in renal repair or the progression of acute kidney injury to chronic kidney disease, but the underlying mechanism of abnormal renal tubular repair remains unclear. In the present study, we investigated the role of heterotrimeric G stimulatory protein α-subunit (Gsa) in renal tubular epithelial cell regeneration. We generated renal tubule epithelium-specific Gsa knockout (GsaKspKO) mice to show the essential role of Gsa in renal tubular epithelial cell regeneration in two AKI models: acute aristolochic acid nephropathy (AAN) and unilateral ischemia-reperfusion injury (UIRI). GsaKspKO mice developed more severe renal impairment after AAN and UIRI, higher serum creatinine levels, and more substantial tubular necrosis than wild-type mice. More importantly, Gsa inactivation impaired renal tubular epithelial cell proliferation by reducing bromodeoxyuridine+ cell numbers in the AAN model and inhibiting cyclin-dependent kinase 2/cyclin E1 expression in the UIRI model. This reduced proliferation was further supported in vitro with Gsa-targeting siRNA. Downregulation of Gsa inhibited tubular epithelial cell proliferation in HK-2 and mIMCD-3 cells. Furthermore, Gsa downregulation inhibited cyclin-dependent kinase 2/cyclin E1 expression, which was dependent on the Raf-MEK-ERK signaling pathway. In conclusion, Gsa is required for tubular epithelial cell regeneration during kidney repair after AKI. Loss of Gsa impairs renal tubular epithelial cell regeneration by blocking the Raf-MEK-ERK pathway.

Time-dependent effects of histone deacetylase inhibition in sepsis-associated acute kidney injury

BackgroundSepsis, a dysregulated host response to infection with results in organ dysfunction, has been a major challenge to the development of effective therapeutics. Sepsis-associated acute kidney injury (S-AKI) results in a 3–5-fold increase in the risk of hospital mortality compared to sepsis alone. The development of therapies to reverse S-AKI could therefore significantly affect sepsis outcomes. However, the translation of therapies from preclinical studies into humans requires model systems that recapitulate clinical scenarios and the development of renal fibrosis indicative of the transition from acute to chronic kidney disease.ResultsHere we characterized a murine model of S-AKI induced by abdominal sepsis developing into a chronic phenotype. We applied a small molecule histone deacetylase-8 inhibitor, UPHD186, and found that early treatment, beginning at 48 h post-sepsis, worsened renal outcome accompanied by decreasing mononuclear cell infiltration in the kidney, skewing cells into a pro-inflammatory phenotype, and increased pro-fibrotic gene expression, while delayed treatment, beginning at 96 h post-sepsis, after the acute inflammation in the kidney had subsided, resulted in improved survival and kidney histology presumably through promoting proliferation and inhibiting fibrosis.ConclusionsThese findings not only present a clinically relevant S-AKI model, but also introduce a timing dimension into S-AKI therapeutic interventions that delayed treatment with UPHD186 may enhance renal histologic repair. Our results provide novel insights into successful repair of kidney injury and sepsis therapy.

Peritoneal M2 macrophage transplantation as a potential cell therapy for enhancing renal repair in acute kidney injury.

Acute kidney injury (AKI) is a clinical condition that is associated with high morbidity and mortality. Inflammation is reported to play a key role in AKI. Although the M2 macrophages exhibit antimicrobial and anti‐inflammatory activities, their therapeutic potential has not been evaluated for AKI. This study aimed to investigate the protective effect of peritoneal M2 macrophage transplantation on AKI in mice. The macrophages were isolated from peritoneal dialysates of mice. The macrophages were induced to undergo M2 polarization using interleukin (IL)‐4/IL‐13. AKI was induced in mice by restoring the blood supply after bilateral renal artery occlusion for 30 minutes. The macrophages were injected into the renal cortex of mice. The changes in renal function, inflammation and tubular proliferation were measured. The M2 macrophages were co‐cultured with the mouse primary proximal tubular epithelial cells (PTECs) under hypoxia/reoxygenation conditions in vitro. The PTEC apoptosis and proliferation were analysed. The peritoneal M2 macrophages effectively alleviated the renal injury and inflammatory response in mice with ischaemia‐reperfusion injury (IRI) and promoted the PTEC proliferation in vivo and in vitro. These results indicated that the peritoneal M2 macrophages ameliorated AKI by decreasing inflammatory response and promoting PTEC proliferation. Hence, the peritoneal M2 macrophage transplantation can serve as a potential cell therapy for renal diseases.

KLF4 Initiates Sustained Activation of YAP After AKI to Promote Renal Fibrosis

Acute renal injury (AKI) has been recognized as long-term risks for progressing into chronic kidney disease (CKD) and interstitial fibrosis. Hippo pathway was previously noticed facilitating the renal tubular repair after AKI. In the ischemia-reperfusion (IR)-induced AKI to CKD animal model, the expression and nucleus distribution of YAP were persistently increased to the end of experiment (21 days after IR surgery). The sustained activation of YAP in post-acute phase of AKI was involved in renal functional decline and interstitial fibrosis. Activation of YAP increased the expression of transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF). Reprogramming factor KLF4 was lined on the upstream of YAP. KLF4 upregulated the expression of YAP and ITCH. ITCH facilitates YAP activation and nuclear translocation via degrading LATS1. Knockdown on KLF4 attenuated the increase in YAP and nuclear translocation as well as renal functional deterioration and interstitial fibrosis. The expression and nuclear distribution of YAP were also increased in biopsy sample from CKD patients. In conclusion, the activation of YAP in the post-acute phase of AKI is implicated in renal functional deterioration and fibrosis although it exhibits beneficial effect in acute phase. Reprogramming factor KLF4 is responsible for the persistent activation of YAP. Shutting down the activation of KLF4-YAP pathway appropriately might be a way to prevent the transition of AKI into CKD. Funding Statement: This research was financially supported by the Natural Science Foundation of China No. 81873603, 81670664 to Lu L and No. 81770718 to Wang X. Declaration of Interests: All the authors declared no conflict of interests exists. Ethics Approval Statement: All experiments using mice were performed according to the criteria of the Medical Laboratory Animal Administrative Committee of Shanghai and the Guide for Care and Use of Laboratory Animals of Fudan University, and protocols were approved by the Ethics Committee for Experimental Research, Shanghai Medical College, Fudan University

Nephroprotective Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR Pathway)

Ischemia reperfusion is determined by a limitation of blood supply to the organs and subsequent blood restoration and reoxygenation. Renal ischemia reperfusion injury (IRI) is a potential element in the pathogenesis of acute kidney injury arising from oxidative stress, inflammation and apoptosis of renal tubular cells. The mammalian target of rapamycin (mTOR) pathway activates after IRI and contributes to renal repair and regeneration. Quercetin is a flavonoid compound that presents in many fruits and vegetables. Quercetin is widely used for its anti-inflammatory and anti-oxidant effects. The present study aimed to investigate the potential protective effect of quercetin on renal IRI in rat model by regulation of Akt/mTOR pathway. At the end of experiment, the serum levels of urea and creatinine and renal tissue levels regarding p-mTOR, p-Akt, IL-1I², caspase-3, and F2-isoprostane were recognized to be significantly (p value<0.05) elevated in control group when compared with sham group. Histopathologic alanalysis of the renal tissues recognized a severe renal injury in control group and there was a significant role of quercetin in ameliorating this injury by minimizing the serum levels of urea and creatinine, tissue levels of IL-1I², caspase-3, F2-isoprostane except for p-mTOR and p-AKt levels which were significantly (p value<0.05) higher in comparison with that of control group. In addition, treatment of quercetin significantly (p<0.05) reversed the histopathologic severity scores of renal tissue damage. From the overall results, we concluded that quercetin significantly diminished renal ischemia reperfusion injury in the rat model through Akt/mTOR pathway by its effect as anti-oxidant, anti-inflammatory and anti-apoptotic. How to Cite this Article Pubmed Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR SRP. 2020; 11(1): 315-325. doi:10.5530/srp.2020.1.41 Web Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR http://www.sysrevpharm.org/?mno=83862 [Access: March 29, 2021]. doi:10.5530/srp.2020.1.41 AMA (American Medical Association) Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR SRP. 2020; 11(1): 315-325. doi:10.5530/srp.2020.1.41 Vancouver/ICMJE Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR SRP. (2020), [cited March 29, 2021]; 11(1): 315-325. doi:10.5530/srp.2020.1.41 Harvard Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi (2020) Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR SRP, 11 (1), 315-325. doi:10.5530/srp.2020.1.41 Turabian Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. 2020. Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR Systematic Reviews in Pharmacy, 11 (1), 315-325. doi:10.5530/srp.2020.1.41 Chicago Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Nephroprotective Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR Pathway). Systematic Reviews in Pharmacy 11 (2020), 315-325. doi:10.5530/srp.2020.1.41 MLA (The Modern Language Association) Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi. Nephroprotective Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR Pathway). Systematic Reviews in Pharmacy 11.1 (2020), 315-325. Print. doi:10.5530/srp.2020.1.41 APA (American Psychological Association) Style Rusul F. Hasan, Murooj L. Altimimi, Hayder M. Alaridy, Najah R. Hadi (2020) Potential Effect of Quercttin in Renal Ischemia Reperfusion Injury in Rat Model (Role of Akt/m TOR Systematic Reviews in Pharmacy, 11 (1), 315-325. doi:10.5530/srp.2020.1.41

Exosomes Derived from GDNF-Modified Human Adipose Mesenchymal Stem Cells Ameliorate Peritubular Capillary Loss in Tubulointerstitial Fibrosis by Activating the SIRT1/eNOS Signaling Pathway

Background: Glial-derived neurotrophic factor (GDNF) has been demonstrated to promote the therapeutic effect of mesenchymal stem cells on ameliorating renal injury. The mechanism may involve the transfer of endogenous molecules, but these factors remain unknown. Methods: GDNF was transfected into human adipose mesenchymal stem cells via a lentiviral transfection system and exosomes were isolated (GDNF-AMSC-exos). Using unilateral ureteral obstruction (UUO) mouse models and human umbilical vein endothelial cells (HUVECs) against hypoxia/serum deprivation (H/SD) injury models we investigated whether GDNF-AMSC-exos ameliorate peritubular capillary (PTC) loss in tubulointerstitial fibrosis, and whether this effect is meditated by SIRT1 signaling pathway. Additionally, by using SIRT1 activators or siRNA, the roles of the candidate mRNA and its downstream gene in GDNF-AMSC-exo-induced regulation of endothelial cell function were assessed. Findings: GDNF-AMSC-exos resulted in significantly decreased PTC rarefaction and renal fibrosis scores in mice with UUO. In vitro studies revealed that GDNF-AMSC-exos exert cytoprotective effects on HUVECs against H/SD injury by stimulating migration, angiogenesis and conferring apoptosis resistance. Mechanistically, GDNF-AMSC-exos enhanced SIRT1 signaling, which accompanied by increased protein levels of phosphorylated eNOS (p-eNOS). In addition, we have confirmed the SIRT1-eNOS interaction in HUVECs by immunoprecipitation. Interpretation: Our study unveils a mechanism by which exosomes ameliorate renal fibrosis: GDNF-AMSC-exos may activate an angiogenesis program in surviving PTCs after injury by activating the SIRT1/eNOS signaling pathway. This finding suggests that inhibition of chronic kidney disease (CKD) progression requires long-term suppression of fibrosis via renal microvascular repair and angiogenesis and that GDNF-AMSC-exos therapy is a promising strategy for achieving this goal. Funding Statement: This work were supported by projects of the National Natural Science Foundation of China (81270769 and 81803473); a project of the Jiangsu Provincial Natural Science Foundation (BK20161172); a project of the Jiangsu Provincial Commission of Health and Family Planning (H201628); projects of the Jiangsu Provincial Post Graduate Innovation Plan (KYCX18-2178, KYCX17-1708, SJCX17-0560, SJCX18-0715); the Municipal Key Research and Development Project of Xuzhou (KC18212); the “Liu ge yi Gong Cheng” project of Jiangsu High-Level Personnel (LGY2016043); a school class project of Xuzhou Medical University (2017KJ13); and the Xuzhou Science and Technology Bureau Applied Basic Research Program( KC18041 and KC 19069). Declaration of Interests: All the authors declared no competing interests. Ethics Approval Statement: Approval of all research involving human participants was obtained from the Institutional Review Board of the Affiliated Hospital of Xuzhou Medical University (permit number: xyfylw2013032). All experiments involving animals followed the animal use protocol enacted by the Institutional Animal Care and Use Committee of Xuzhou Medical University.

Mitochondria transfer via tunneling nanotubes is an important mechanism by which CD133+ scattered tubular cells eliminate hypoxic tubular cell injury

Renal CD133+scattered tubular cells (STCs) have been regarded as progenitor-like cells in the kidney and participated in ischemic renal injury repair. However, the mechanism of this effect is not fully elucidated yet. The primary objective of this study was to investigate the hypothesis that the protective effect of CD133+STCs depends on the transfer of mitochondria to injured tubular cells invitro. In this study, renal ischemic reperfusion injury (IRI) rat model was established with one side kidney ischemic for 45 min and animals were sacrificed at 48 h after operation. Tubular cells were isolated and cultured invitro, and then CD133+STCs were selected from the cultured cells. Then, CD133+STCs were co-cultured with CD133-tubular cells (TECs) to detect the tunneling nanotubes like structures, and the transfer of mitochondria from CD133+STCs to injured tubular cells were detected by fluorescent imaging and flow cytometry. Further, cellular protective effects of CD133+STCs were tested when cultured with TECs under hypoxic conditions. In results, renal CD133+STCs were scattered throughout the normal kidney and increased upon ischemic injury. Nanotube formations were commonly found between CD133+STCs and TECs, and the transfer of mitochondria was detected from CD133+STCs to TECs. Further, CD133+STCs exist significant anti-apoptosis and pro-proliferation effects for TECs under hypoxic culture conditions. Thus, this study was first described that renal CD133+STCs could transfer mitochondria to injured TECs invitro for its protective effects, which revealed an important novel mechanism for renal repair after ischemic injury.

Periostin Promotes Cell Proliferation and Macrophage Polarization to Drive Repair after AKI.

The matricellular protein periostin has been associated with CKD progression in animal models and human biopsy specimens. Periostin functions by interacting with extracellular matrix components to drive collagen fibrillogenesis and remodeling or by signaling through cell-surface integrin receptors to promote cell adhesion, migration, and proliferation. However, its role in AKI is unknown. We used mice with conditional tubule-specific overexpression of periostin or knockout mice lacking periostin expression in the renal ischemia-reperfusion injury model, and primary cultures of isolated tubular cells in a hypoxia-reoxygenation model. Tubular epithelial cells showed strong production of periostin during the repair phase of ischemia reperfusion. Periostin overexpression protected mice from renal injury compared with controls, whereas knockout mice showed increased tubular injury and deteriorated renal function. Periostin interacted with its receptor, integrin-β1, to inhibit tubular cell cycle arrest and apoptosis in in vivo and in vitro models. After ischemia-reperfusion injury, periostin-overexpressing mice exhibited diminished expression of proinflammatory molecules and had more F4/80+ macrophages compared with knockout mice. Macrophages from periostin-overexpressing mice showed increased proliferation and expression of proregenerative factors after ischemia-reperfusion injury, whereas knockout mice exhibited the opposite. Coculturing a macrophage cell line with hypoxia-treated primary tubules overexpressing periostin, or treating such macrophages with recombinant periostin, directly induced macrophage proliferation and expression of proregenerative molecules. In contrast to the detrimental role of periostin in CKD, we discovered a protective role of periostin in AKI. Our findings suggest periostin may be a novel and important mediator of mechanisms controlling renal repair after AKI.