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Abnormal lipid metabolism in renal tubular epithelial cells contributes to renal lipid accumulation and disturbed mitochondrial bioenergetics which are important in diabetic kidney disease. Berberine, the major active constituent of Rhizoma coptidis and Cortex phellodendri, is involved in regulating glucose and lipid metabolism. The present study aimed to investigate the protective effects of berberine on lipid accumulation in tubular epithelial cells of diabetic kidney disease. We treated type 2 diabetic db/db mice with berberine (300 mg/kg) for 12 weeks. Berberine treatment improved the physical and biochemical parameters of the db/db mice compared with db/m mice. In addition, berberine decreased intracellular lipid accumulation and increased the expression of fatty acid oxidation enzymes CPT1, ACOX1 and PPAR-α in tubular epithelial cells of db/db mice. The mitochondrial morphology, mitochondrial membrane potential, cytochrome c oxidase activity, mitochondrial reactive oxygen species, and mitochondrial ATP production in db/db mice kidneys were significantly improved by berberine. Berberine intervention activated the AMPK pathway and increased the level of PGC-1α. In vitro berberine suppressed high glucose-induced lipid accumulation and reversed high glucose-induced reduction of fatty acid oxidation enzymes in HK-2 cells. Importantly, in HK-2 cells, berberine treatment blocked the change in metabolism from fatty acid oxidation to glycolysis under high glucose condition. Moreover, berberine restored high glucose-induced dysfunctional mitochondria. These data suggested that berberine alleviates diabetic renal tubulointerstitial injury through improving high glucose-induced reduction of fatty acid oxidation, alleviates lipid deposition, and protect mitochondria in tubular epithelial cells.

The pyroptosis of renal tubular epithelial cells leads to tubular loss and inflammation and then promotes renal fibrosis. The transcription factor Krüppel-like factor 4 (KLF4) can bidirectionally regulate the transcription of target genes. Our previous study revealed that sustained elevation of KLF4 is responsible for the transition of acute kidney injury (AKI) into chronic kidney disease (CKD) and renal fibrosis. In this study, we explored the upstream mechanisms of renal tubular epithelial cell pyroptosis from the perspective of posttranslational regulation and focused on the transcription factor KLF4. Mice were subjected to unilateral ureteral obstruction (UUO) surgery and euthanized on D7 or D14 for renal tissue harvesting. We showed that the pyroptosis of renal tubular epithelial cells mediated by both the Caspase-1/GSDMD and Caspase-3/GSDME pathways was time-dependently increased in UUO mouse kidneys. Furthermore, we found that the expression of the transcription factor KLF4 was also upregulated in a time-dependent manner in UUO mouse kidneys. Tubular epithelial cell-specific Klf4 knockout alleviated UUO-induced pyroptosis and renal fibrosis. In Ang II-treated mouse renal proximal tubular epithelial cells (MTECs), we demonstrated that KLF4 bound to the promoter regions of Caspase-3 and Caspase-1 and directly increased their transcription. In addition, we found that ubiquitin-specific protease 11 (USP11) was increased in UUO mouse kidneys. USP11 deubiquitinated KLF4. Knockout of Usp11 or pretreatment with the USP11 inhibitor mitoxantrone (3 mg/kg, i.p., twice a week for two weeks before UUO surgery) significantly alleviated the increases in KLF4 expression, pyroptosis and renal fibrosis. These results demonstrated that the increased expression of USP11 in renal tubular cells prevents the ubiquitin degradation of KLF4 and that elevated KLF4 promotes inflammation and renal fibrosis by initiating tubular cell pyroptosis., (© 2024. The Author(s), under exclusive licence to Shanghai Institute of Materia Medica, Chinese Academy of Sciences and Chinese Pharmacological Society.)

Background: Urine sediment examination is a time-tested and non-invasive diagnostic tool. This study investigated the characteristics of urine sediment and its association with severity and renal outcomes in diabetic nephropathy (DN) patients., Methods: A total of 201 biopsy-proven diabetic nephropathy patients (according to the pathological classification of diabetic nephropathy proposed by the Renal Pathology Society in 2010) who underwent manual urine sediment microscopic examination were included. We compared the clinicopathological characteristics of diabetic nephropathy patients with and without urinary renal tubular epithelial cells (RTECs) or renal tubular epithelial cell casts. The predictive value of urinary renal tubular epithelial cells or renal tubular epithelial cell casts for renal outcomes in diabetic nephropathy was analyzed., Results: Fifty of 201 (24.9%) diabetic nephropathy patients had renal tubular epithelial cells or renal tubular epithelial cell casts in urine sediment. Diabetic nephropathy patients with renal tubular epithelial cells or renal tubular epithelial cell casts in urine sediment had a significantly higher level of proteinuria [6.0 (3.1, 9.7) vs. 3.6 (1.8, 6.8) g/24 h, p = 0.001], higher serum creatinine [227.9 (151.6, 338.1) vs. 177.0 (104.4, 288.4) μmol/L, p = 0.016] and lower estimated glomerular filtration rate (eGFR) [25.8 (15.8, 44.8) vs. 35.7 (19.9, 65.0) mL/min/1.73 m 2 , p = 0.025] than those without. Cox regression analysis demonstrated that the presence of urinary renal tubular epithelial cells or renal tubular epithelial cell casts was independently associated with the development of end-stage kidney disease (ESKD) in diabetic nephropathy patients [HR 1.670, 95% CI (1.042, 2.676), p = 0.033]. Adding the presence of urinary renal tubular epithelial cells or renal tubular epithelial cell casts to the predictive model could improve the effectiveness of the model for predicting the risk of ESKD within one year after renal biopsy., Conclusions: The presence of urinary renal tubular epithelial cells or renal tubular epithelial cell casts was associated with more severe kidney injury and worse renal outcomes in patients with diabetic nephropathy, thus perhaps providing a noninvasive biomarker for predicting diabetic nephropathy., (© 2024. The Author(s) under exclusive licence to Italian Society of Nephrology.)

Background: Age-related kidney failure is often induced by a decrease in the bioavailability of tubular epithelial cells in elderly chronic kidney disease (CKD) patients. BRD4, an epigenetic regulator and a member of the bromodomain and extraterminal (BET) protein family, acts as a super-enhancer (SE) organizing and regulating genes expression during embryogenesis and cancer development. But the physiological function of BRD4 in normal cells has been less studied. This study aimed to research certain biological roles of BRD4 in the process of normal cell aging and discuss the potential mechanisms., Methods: In this study, we investigated the biological functions of BRD4 proteins in the aging of renal tubular cells. At first, we used a D-galactose (D-gal) and BRD4 inhibitor (Abbv-075) to replicate kidney senescence in vivo . D-gal and Abbv-075 were then used to measure the aging-related changes, such as changes in cell cycle, β-galactosidase activity, cell migration, and p16 protein expression in vitro . At last, we knocked down and over-expressed BRD4 to investigate the aging-related physiological phenomena in renal tubular cells., Results: In vitro , D-gal treatment induced noticeable aging-related changes such as inducing cell apoptosis and cell cycle arrest, increasing β-galactosidase activity as well as up-regulating p16 protein expression in primary human tubular epithelial cells. In the aging mice model, D-gal significantly induced renal function impairment and attenuated BRD4 protein expression. At the same time, the BRD4 inhibitor (Abbv-075) was able to mimic D-gal-induced cell senescence. In vivo , Abbv-075 also decreased kidney function and up-regulated p21 protein expression. When we knocked down the expression of BRD4, the senescence-associated β-galactosidase (SA-β-gal) activity increased dramatically, cell migration was inhibited, and the proportion of cells in the G0/G1 phase increased. Additionally, the knockdown also promoted the expression of the senescence-related proteins p16. When the renal tubular cells were overexpressed with BRD4, cell aging-related indicators were reversed in the D-gal-induced cell aging model., Conclusions: BRD4 appears to have an active role in the aging of renal tubular cells in vivo and in vitro . The findings also suggest that BRD4 inhibitors have potential nephrotoxic effects for oncology treatment. BRD4 may be a potential therapeutic biomarker and drug target for aging-related kidney diseases, which warrants additional studies., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-24-214/coif). The authors have no conflicts of interest to declare., (2024 Translational Andrology and Urology. All rights reserved.)

Diabetic nephropathy is considered one of the most common microvascular complications of diabetes and the pathophysiology involves multiple factors. Progressive diabetic nephropathy is believed to be related to the structure and function of the tubular epithelial cells in the kidney. However, the role of lysine acetylation in lesions of the renal tubular epithelial cells arising from hyperglycemia is poorly understood. Consequently, in this study, we cultured mouse renal tubular epithelial cells in vitro under high glucose conditions and analyzed the acetylation levels of proteins by liquid chromatography-high-resolution mass spectrometry. We identified 48 upregulated proteins and downregulated 86 proteins. In addition, we identified 113 sites with higher acetylation levels and 374 sites with lower acetylation levels. Subcellular localization analysis showed that the majority of the acetylated proteins were located in the mitochondria (43.17%), nucleus (28.57%) and cytoplasm (16.19%). Enrichment analysis indicated that these acetylated proteins are primarily associated with oxidative phosphorylation, the citrate cycle (TCA cycle), metabolic pathways and carbon metabolism. In addition, we used the MCODE plug-in and the cytoHubba plug-in in Cytoscape software to analyze the PPI network and displayed the first four most compact MOCDEs and the top 10 hub genes from the differentially expressed proteins between global and acetylated proteomes. Finally, we extracted 37 conserved motifs from 4915 acetylated peptides. Collectively, this comprehensive analysis of the proteome reveals novel insights into the role of lysine acetylation in tubular epithelial cells and may make a valuable contribution towards the identification of the pathological mechanisms of diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of microRNA-21（miR-21）on renal tubular epithelial cells（NRK- 52E）injured by hypoxia/reoxygenation（H/R）in rats. Methods NRK-52E cells were cultured in vitro and randomly divided into 4 groups：pre-miR-21+H/R group，antagomiR-21+H/R group，model group，and normal group. The H/R injury models were established in the model group，and the cells in the normal group were routinely cultured. The cells in the pre-miR-21+H/R group and the antagomiR-21+H/R group were pre-treated with pre-miR-21 and antagomiR-21 at a final concentration of 30 nmol/L 24 h before hypoxia，respectively. Cell viability was detected by CCK-8，the apoptosis rate was measured by flow cytometry，miR-21 and PDCD4 mRNA expression levels were detected by RT-PCR，and Caspase-3 protein was detected by Western blotting. The activity of antioxidant enzymes and total antioxidant capacity of cells were detected by chemical colorimetry and endpoint colorimetry，and inflammatory cytokines in supernatant of cell culture were detected by ELISA. Results Compared with the normal group，the model group had lower cell viability，higher apoptosis rate，higher relative expression level of miR-21，lower relative expression level of PDCD4 mRNA，higher relative expression level of Caspase-3 protein P17，lower antioxidant enzyme activity and total antioxidant capacity，and higher level of inflammatory cytokines（all P<0. 05）. Compared with the model group，the pre-miR-21 +H/R group had higher cell viability， lower apoptosis rate，lower relative expression level of miR-21，higher relative expression level of PDCD4 mRNA， lower relative expression level of Caspase-3 protein P17，higher antioxidant enzyme activity and total antioxidant capacity， and lower level of inflammatory cytokines（all P<0. 05）. There was no significant difference between antagomiR-21+H/R group and model group in the indicators except the relative expression of miR-21（all P>0. 05）. Conclusion MiR-21 can inhibit the apoptosis of NRK-52E cells damaged by H/R，increase the antioxidant capacity of NRK-52E cells，and alleviate inflammation. [ABSTRACT FROM AUTHOR]

Objective To investigate the effects of erythropoietin (EPO) intervening in human umbilical cord mesenchymal stem cells (HUMSCs) on the fibrosis of human renal tubular epithelial cell line HK-2. Methods HUMSCs and HK-2 cells were cultured, respectively. The optimal concentration of EPO in HUMSCs migration and proliferation was 100 IU/mL by Transwell assay and MTT assay, and the optimal concentration of transforming growth factor-β1 (TGF-β1)in HK-2 cell fibrosis was 10 μg/L by RT-PCR and Western blotting. The HK-2 cells were divided into 4 groups: control group (simple medium was in the upper chamber, and HK-2 cells and medium were in the lower chamber), TGF-β1 group (simple medium was in the upper chamber, and HK-2 cells added with 10 μg/L TGF-β1 were in the lower chamber), HUMSCs intervention group (HUMSCs and medium were in the upper chamber, and HK-2 cells added with 10 μg/L TGF-β1 medium were in the lower chamber), and EPO+HUMSCs intervention group (HUMSCs added with 100 IU/mL EPO were in the upper chamber, and HK-2 cells added with 10 μg/L TGF-β1 were in the lower chamber). After 72 h of culture, the morphology and growth of cells were observed under the microscope, and the number of transmembrane cells was counted. RT-PCR was used to detect the relative mRNA expression levels of fibrosis factors TGF-β1, fibronectin (FN), Col Ⅳ, α-smooth muscle actin (α-SMA), and homing factors stromal cell-derived factor1 (SDF-1) and its receptor CXCR4stem cell factor (SCF) and its receptor c-Kit in the HK-2 cells; the relative protein expression levels of fibrosis factors and homing factors were determined by Western blotting. Results Compared with the control group, after TGF-β1 intervention, HK-2 cells lost their original epithelial cell morphology and formed epithelioid cells and myofibroblasts with migration ability in the TGF-β1 group. Compared with the control group, the number of cell migration increased in the TGF-β1 group, HUMSCs intervention group, and EPO+HUMSCs intervention group; the number of cell migration in the EPO+ HUMSCs intervention group was lower than those in the HUMSCs intervention group and TGF-β1 group (all P<0. 01). Compared with the control group, the mRNA and protein levels of TGF-β1, FN, ColⅣ, α-SMA, CXCR4, SDF-1, c-Kit and SCF in the TGF-β1 group were the highest, followed by those in the HUMSCs intervention group, and those in the EPO+HUMSCs intervention group were the lowest (P<0. 05 or P<0. 01). Conclusion EPO can promote the proliferation and migration of HUMSCs, direct the migration of HUMSCs to the damaged HK-2, inhibit the differentiation of HK-2 into non-functional epithelial cells with migration ability, and delay the progression of fibrosis of renal tubular epithelial cells. [ABSTRACT FROM AUTHOR]

Renal fibrosis is a failed wound-healing process of the kidney tissue after chronic, sustained injury, which is a common pathway and pathological marker of virtually every type of chronic kidney disease (CKD), regardless of cause. However, there is a lack of effective treatment specifically targeting against renal fibrosis per se to date. The main pathological feature of renal fibrosis is the massive activation and proliferation of renal fibroblasts and the excessive synthesis and secretion of extracellular matrix (ECM) deposited in the renal interstitium, leading to structural damage, impairment of renal function, and eventually end-stage renal disease. In this review, we summarize recent advancements regarding the participation and interaction of many types of kidney residents and infiltrated cells during renal fibrosis, attempt to comprehensively discuss the mechanism of renal fibrosis from the cellular level and conclude by highlighting novel therapeutic targets and approaches for development of new treatments for patients with renal fibrosis.

Diabetic nephropathy is considered one of the most common microvascular complications of diabetes and the pathophysiology involves multiple factors. Progressive diabetic nephropathy is believed to be related to the structure and function of the tubular epithelial cells in the kidney. However, the role of lysine acetylation in lesions of the renal tubular epithelial cells arising from hyperglycemia is poorly understood. Consequently, in this study, we cultured mouse renal tubular epithelial cells in vitro under high glucose conditions and analyzed the acetylation levels of proteins by liquid chromatography-high-resolution mass spectrometry. We identified 48 upregulated proteins and downregulated 86 proteins. In addition, we identified 113 sites with higher acetylation levels and 374 sites with lower acetylation levels. Subcellular localization analysis showed that the majority of the acetylated proteins were located in the mitochondria (43.17%), nucleus (28.57%) and cytoplasm (16.19%). Enrichment analysis indicated that these acetylated proteins are primarily associated with oxidative phosphorylation, the citrate cycle (TCA cycle), metabolic pathways and carbon metabolism. In addition, we used the MCODE plug-in and the cytoHubba plug-in in Cytoscape software to analyze the PPI network and displayed the first four most compact MOCDEs and the top 10 hub genes from the differentially expressed proteins between global and acetylated proteomes. Finally, we extracted 37 conserved motifs from 4915 acetylated peptides. Collectively, this comprehensive analysis of the proteome reveals novel insights into the role of lysine acetylation in tubular epithelial cells and may make a valuable contribution towards the identification of the pathological mechanisms of diabetic nephropathy.

Acute kidney injury (AKI) is defined as a pathological condition in which the glomerular filtration rate decreases rapidly over a short period of time, resulting in changes in the physiological function and tissue structure of the kidney. An increasing amount of evidence indicates that there is an inseparable relationship between acute kidney injury and chronic kidney disease (CKD). With the progress in research in this area, researchers have found that the recovery of AKI may also result in the occurrence of CKD due to its own maladaptation and other potential mechanisms, which involve endothelial cell injury, inflammatory reactions, progression to fibrosis and other pathways that promote the progress of the disease. Based on these findings, this review summarizes the occurrence and potential mechanisms of maladaptive repair in the progression of AKI to CKD and explores possible treatment strategies in this process so as to provide a reference for the inhibition of the progression of AKI to CKD.

Purpose: To determine the potential effect of ruscogenin in cisplatin-induced nephrotoxicity. Methods: Rat renal tubular epithelial cells (NRK-52E) were treated with 50 µM cisplatin to establish an in vitro cell model of nephrotoxicity. Cytotoxicity was assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay, flow cytometry, and western blot. Different concentrations of ruscogenin (2.5, 5, and 10 μM) were incubated with cisplatin-treated NRK-52E cells. Alterations in the nod-like receptor family, the pyrin domain-containing protein (NLRP3) inflammasome, toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κ B), and nuclear factor erythropoietin-2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) components were determined using western blot. Flow cytometry was also used to investigate the levels of reactive oxygen species (ROS). Results: Ruscogenin significantly increased cell viability (p < 0.01) and suppressed apoptosis of NRK- 52E cells (p < 0.01), attenuating cisplatin-induced cytotoxicity. The NLRP3 inflammasome was activated in cisplatin-treated NRK-52E cells with enhanced NLRP3, interleukin 1 beta, and cleaved caspase-1; however, ruscogenin significantly decreased the expression of NLRP3 inflammasome components (p < 0.01). Ruscogenin attenuated cisplatin-induced expression of TLR4, myeloid differentiation primary response 88, and NF-κ B. Further, cisplatin induction enhanced ROS formation, with increased malondialdehyde and decreased glutathione reductase and catalase levels. Ruscogenin attenuated cisplatin-induced ROS accumulation in NRK-52E cells through up-regulation of Nrf2 and HO-1. Conclusion: Ruscogenin protects against cisplatin-induced apoptosis, inflammation, and oxidative stress in renal tubular epithelial cells via suppression of TLR4/NF-κ B activation and promotion of Nrf2/HO-1 activation. herefore, ruscogenin provides a potential therapeutic strategy for mitigating cisplatin-induced nephrotoxicity [ABSTRACT FROM AUTHOR]

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Aberrant expression of B cell–activating factor belonging to TNF superfamily (BAFF) and its receptors results in abnormal biological activities in hematopoietic and non-hematopoietic cells and is closely associated with the occurrence and development of various diseases. However, the biological significance and potential mechanisms underlying BAFF signaling in renal tubular epithelial cells (RTECs) remain unknown. This study aimed to investigate the biological role of BAFF signaling in RTECs. Mice primary RTECs were applied. The proliferation status and apoptotic rates were examined by MTS assay and flow cytometry, respectively. The expression of BAFF and its receptors was analyzed via flow cytometry and sodium ion transport function, and cytokeratin-18 expression was detected through immunofluorescence staining. In addition, Pin1 was knocked down via siRNA and its expression was assessed through reverse transcription PCR. Lastly, western blotting was performed to analyze E-cadherin, ɑ-SMA, and Pin1 expression. Results suggested that BAFF-R was significantly upregulated upon IFN-γ stimulation, and enhancement of BAFF signaling promoted cell survival and reduced their apoptotic rate, while simultaneously reducing the epithelial phenotype and promoting the interstitial transformation of cells. Furthermore, Pin1 was significantly increased, along with the upregulation of BAFF signaling in the RTECs, and participated in interstitial transformation induced by BAFF signaling. Collectively, the present results elucidate the potential mechanism of loss of normal function of RTECs under long-term high dose of BAFF stimulation provides a potential therapeutic target for renal interstitial fibrosis, and underlining mechanisms of shortening of long-term outcomes of kidney allografts via augmenting of BAFF signaling. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the absorption of alkaloids from Phellodendri chinensis Cortex (PC) by human renal tubular epithelial cells (HK-2). Cellular uptake and affinity ultrafiltration assays were employed to determine the alkaloid uptake pathway in HK-2 cells. Stemming from the hypothesis that salt-water processed PC introduces these alkaloids into the kidney at a cellular level, this research focused on different processed products of PC that are tailored for renal targeting. Utilizing the UPLC-QqQ-MS method, we quantified variations in the uptake capacity of phellodendrine, magnoflorine, jatrorrhizine, berberrubine, and berberine from raw Phellodendri chinensis Cortex (RPC), salt-water processed Phellodendri chinensis Cortex (SPC), and wine processed Phellodendri chinensis Cortex (WPC) in HK-2 cells. This study also tracked the concentration changes of these five alkaloids in HK-2 cells during the administration phase. Further, we evaluated the influence of two inhibitors on the absorption of these five alkaloids from PC and its processed products into HK-2 cells: the organic anion transporters (OATs) inhibitor—probenecid (PRO), and the organic cationic transporters (OCTs) inhibitor—tetraethylammonium chloride (TEAC). A pivotal component of this research was an investigation into the effects of PC and its processed products on the expression levels of OCT2, OAT1, and OAT3 proteins in HK-2 cells, facilitated by Western blot analysis. Finally, we appraised the binding affinity of PC's alkaloids to OCT2, OAT1, and OAT3 proteins using an ultrafiltration centrifugation technique. The uptake of different processed products of PC by HK-2 cells showed the following trend: SPC group > RPC group > WPC group. When considering inhibitor uptake in HK-2 cells, the group treated with PRO (an OATs inhibitor) demonstrated a higher uptake than the group treated with TEAC (an OCTs inhibitor). It was observed that different processed products of PC elevated the expression of OCT2 and OAT1 proteins in HK-2 cells. Specifically, both the SPC and berberrubine groups displayed enhanced expression of these proteins, with a marked increase noted for OCT2. Through affinity ultrafiltration assays, it was determined that the binding affinity of alkaloids from different processed products of PC to OCT2 and OAT1 significantly exceeded that to OAT3. These results indicate that PC-derived alkaloids are absorbed by HK-2 cells, predominantly through transport mechanisms mediated by OCT2 and OAT1, with OCT2 serving as the dominant transporter. The higher intake of alkaloids in SPC group can likely be linked to the amplified activity of kidney uptake transporters. • The uptake content of alkaloids from Phellodendri chinensis Cortex by HK-2 cells was determined for the first time. • The binding rate of transporter in HK-2 cells to alkaloids in P. chinensis Cortex was investigated for the first time. • The effects of alkaloids in P. chinensis Cortex on the expression of transporters in HK-2 cells were investigated for the first time. • The traditional theory of Chinesemedicines of "stir-fried with salt to enter the kidney." was verified to a certain degree. [ABSTRACT FROM AUTHOR]

Swainsonine (SW) is the main toxic component of locoweed. Previous studies have shown that kidney damage is an early pathologic change in locoweed poisoning in animals. Trehalose induces autophagy and alleviates lysosomal damage, while its protective effect and mechanism against the toxic injury induced by SW is not clear. Based on the published literature, we hypothesize that transcription factor EB(TFEB) -regulated is targeted by SW and activating TFEB by trehalose would reverse the toxic effects. In this study, we investigate the mechanism of protective effects of trehalose using renal tubular epithelial cells. The results showed that SW induced an increase in the expression level of microtubule-associated protein light chain 3-II and p62 proteins and a decrease in the expression level of ATPase H+ transporting V1 Subunit A, Cathepsin B, Cathepsin D, lysosome-associated membrane protein 2 and TFEB proteins in renal tubular epithelial cells in a time and dose-dependent manner suggesting TFEB-regulated lysosomal pathway is adversely affected by SW. Conversely, treatment with trehalose, a known activator of TFEB promote TFEB nuclear translocation suggesting that TFEB plays an important role in protection against SW toxicity. We demonstrated in lysosome staining that SW reduced the number of lysosomes and increased the luminal pH, while trehalose could counteract these SW-induced effects. In summary, our results demonstrated for the first time that trehalose could alleviate the autophagy degradation disorder and lysosomal damage induced by SW. Our results provide an interesting method for reversion of SW-induced toxicity in farm animals and furthermore, activation of TFEB by trehalose suggesting novel mechanism of treating lysosomal storage diseases. • Swainsonine could induce autophagy, inhibit the degradation of autophagosome and cause lysosomal damage. • Trehalose can alleviate the cellular autophagic degradation disorder and lysosomal damage induced by swainsonine. • Trehalose can activate TFEB by promoting nuclear translocation and revserse swainsonine-induced adverse effects. [ABSTRACT FROM AUTHOR]

Gan-song Yin is derived from the classic ancient prescription " Gan-song pill " for the treatment of wasting-thirst in Ningxia combined with the characteristic "fragrant medicine". It is clinically used for the treatment of early renal fibrosis caused by diabetic nephropathy. Previous studies have shown that it has a good effect and great potential in the prevention and treatment of diabetic nephropathy, but its mechanism research is still limited. To investigate the mechanism of GSY to improve DN by interfering with miR-21-5p and glycolipid metabolism in adipocyte exosomes using 3T3-L1 and TCMK-1 co-culture system. The co-culture system of 3T3-L3 and TCMK-1 was established, the IR model was established, and the stability, lipid drop change, glucose consumption, triglyceride content, cell viability, cell cycle and apoptosis level, protein content and mRNA expression of the IR model were detected. GSY inhibited 3T3-L1 activity, increased glucose consumption and decreased TG content. Decreased TCMK-1 cell viability, inhibited apoptosis, cell cycle arrest occurred in G0/G1 phase and S phase. Adipocyte IR model and co-culture system were stable within 48 h. After GSY intervention, lipid droplet decomposition and glucose consumption increased. The TG content of adipocytes increased, while the TG content of co-culture system decreased. GSY can regulate the expression of TGF-β1/SMAD signaling pathway protein in IR state. After GSY intervention, the expression of miR-21-5p was increased in 3T3-L1 and Exo cells, and decreased in TCMK-1 cells. GSY can regulate TGF-β1/SMAD signaling pathway through the secretion of miR-21-5p from adipocytes, protect IR TCMK-1, regulate the protein and mRNA expression levels of PPARγ, GLUT4, FABP4, and improve glucose and lipid metabolism. [Display omitted] • GSY improves glycolipid metabolism. • GSY protects renal tubule epithelial injury. • This study involved exosome-derived miRNAs. [ABSTRACT FROM AUTHOR]

Impaired fatty acid oxidation (FAO) is a metabolic hallmark of renal tubular epithelial cells (RTECs) under diabetic conditions. Disturbed FAO may promote cellular oxidative stress and insufficient energy production, leading to ferroptosis subsequently. Canagliflozin, an effective anti-hyperglycemic drug, may exert potential reno-protective effects by upregulating FAO and inhibiting ferroptosis in RTECs. However, the mechanisms involved remain unclear. The present study is aimed to characterize the detailed mechanisms underlying the impact of canagliflozin on FAO and ferroptosis. Type 2 diabetic db/db mice were administrated daily by gavage with canagliflozin (20 mg/kg/day, 40 mg/kg/day) or positive control drug pioglitazone (10 mg/kg/day) for 12 weeks. The results showed canagliflozin effectively improved renal function and structure, reduced lipid droplet accumulation, enhanced FAO with increased ATP contents and CPT1A expression, a rate-limiting enzyme of FAO, and relieved ferroptosis in diabetic mice. Moreover, overexpression of FOXA1, a transcription factor related with lipid metabolism, was observed to upregulate the level of CPT1A, and further alleviated ferroptosis in high glucose cultured HK-2 cells. Whereas FOXA1 knockdown had the opposite effect. Mechanistically, chromatin immunoprecipitation assay and dual-luciferase reporter gene assay results demonstrated that FOXA1 transcriptionally promoted the expression of CPT1A through a sis-inducible element located in the promoter region of the protein. In conclusion, these data suggest that canagliflozin improves FAO and attenuates ferroptosis of RTECs via FOXA1-CPT1A axis in diabetic kidney disease. [Display omitted] • Canagliflozin can ease lipid metabolism disorders and renal dysfunction in diabetic mice. • Canagliflozin can promote fatty acid oxidation and relieve ferroptosis in HK-2 cells cultured with high glucose. • The protective effect of canagliflozin in diabetic kidney disease may be achieved through FOXA1-CPT1A axis. [ABSTRACT FROM AUTHOR]

Background: M2 macrophages have important roles in diseases such as tumours, cardiovascular diseases and renal diseases. This study aimed to determine the effects and protective mechanism of M2 macrophages against oxidative stress injury and apoptosis induced by calcium oxalate crystals (CaOx) in renal tubular epithelial cells (HK-2) under coculture conditions. Methods: THP-1 cells were induced to differentiate into M2 macrophages by using phorbol-12-myristate-13-acetate, IL-4 and IL-13. Morphological features were observed by microscopy. Phenotypic markers were identified by reverse transcription-polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay (ELISA). HK-2 cells were treated with 0.5 mg/mL CaOx crystals and co-cultured with M2 macrophages or apocynin. The viability of HK-2 cells was detected by CCK-8 assay. The lactate dehydrogenase (LDH) activity of HK-2 cells was analysed using a microplate reader. The apoptosis of HK-2 cells was examined by flow cytometry and Hoechst 33258 staining. Reactive oxygen species (ROS) expression and mitochondrial membrane potential in HK-2 cells were detected by a fluorescence microplate reader. Western blot analysis was conducted to detect the expression of p47phox, Bcl-2, cleaved caspase-3, cytochrome c, p38 MAPK, phospho-p38 MAPK, Akt and phospho-Akt. Results: The results of morphology, reverse transcription-polymerase chain reaction, Western blot and ELISA showed that THP-1 cells were successfully polarised to M2 macrophages. The results of co-culture suggested that M2 macrophages or apocynin significantly increased the cell viability and decreased the LDH activity and apoptosis rate after HK-2 cells were challenged with CaOx crystals. The expression of the p47phox protein and the concentration of ROS were reduced, the release of mitochondrial membrane potential and the expression of the Bcl-2 protein were upregulated and the protein expression of cleaved caspase-3 and cytochrome c was downregulated. The expression of the phosphorylated form of p38 MAPK increased. Under coculture conditions with M2 macrophages, the Akt protein of HK-2 cells treated with CaOx crystals was dephosphorylated, but the phosphorylated form of Akt was not reduced by apocynin. Conclusions: M2 macrophages reduced the oxidative stress injury and apoptosis of HK-2 cells by downregulating the activation of NADPH oxidase, reducing the production of ROS, inhibiting the phosphorylation of p38 MAPK and enhancing the phosphorylation of Akt. We have revealed one of the possible mechanisms by which M2 macrophages reduce the formation of kidney stones.

Diabetic nephropathy (DN) has become the leading cause of end-stage renal disease (ESRD) worldwide. Renal tubular injury plays an important role in the development and progression of DN. And apoptosis of renal tubular epithelial cells (RTEC) contribute to the loss of renal function, increased levels of serum creatinine (SCr), blood urea nitrogen (BUN), urine total protein to urine creatinine and microalbuminuria and reduction of creatinine clear rate (CCr). Moreover, recent findings suggested that endoplasmic reticulum (ER) stress may lead to apoptosis of renal cells. Astragalosides IV (AS-IV) has a variety of pharmacological effects such as anti-apoptosis. Thus, in this study we investigated the effects and mechanisms of AS-IV on apoptosis of RTEC in high-fat diets (HFD) and low-dose streptozotocin (STZ)-induced type 2 DN rats. The results showed that AS-IV (40, 80 mg/kg) could alleviate RTEC apoptosis in DN rats. Furthermore, body weight, the majority of biochemical and renal function parameters and histopathological changes in the diabetic kidney were also improved by AS-IV. And AS-IV could reduce the expression of apoptosis-related proteins cleaved caspase-3, Bax/Bcl-2 ratio. ER stress-related proteins GRP78, p-PERK, ATF4 and CHOP were also inhibited by AS-IV in kidney of DN rats. Taken together, our study suggests that the protective effects of AS-IV may be related to inhibit ER stress-induced apoptosis through down-regulating the expression of p-PERK, ATF4 and CHOP. And our study provides a new theoretical basis for the clinical treatment of patients with kidney diseases.

Renal hypoxia and its associated oxidative stress is a common pathway for the development of kidney diseases, and using dietary antioxidants such as flavan-3-ols to prevent kidney failure has received much attention. This study investigates the molecular mechanism by which flavan-3-ols prevent hypoxia-induced cell death in renal tubular epithelial cells. Human kidney proximal tubular cells (HKC-8) were exposed to hypoxia (1% O2) in the presence of flavan-3-ols (catechin, epicatechin, procyanidin B1, and procyanidin B2). Cell death was examined using flow cytometric analysis. Gene expression was determined using a PCR array and Western blotting, and its network and functions were investigated using STRING databases. Here, we show that the cytoprotective activity of catechin was the highest among these flavan-3-ols against hypoxia-induced cell death in cultured HKC-8 cells. Exposure of HKC-8 cells to hypoxia induced oxidative stress leading to up-regulation of DUOX2, NOX4, CYBB and PTGS2 and down-regulation of TXNRD1 and HSP90AA1. Treatment with catechin or other flavan-3-ols prevented the down-regulation of TXNRD1 expression in hypoxic HKC-8 cells. Overexpression of TXNRD1 prevented hypoxia-induced cell death, and inactivation of TXNRD1 with TRi-1, a specific TXNRD1 inhibitor, reduced the catechin cytoprotection against hypoxia-induced HKC-8 cell death. In conclusion, flavan-3-ols prevent hypoxia-induced cell death in human proximal tubular epithelial cells, which might be mediated by their maintenance of TXNRD1 expression, suggesting that enhancing TXNRD1 expression or activity may become a novel therapeutic strategy to prevent hypoxia-induced kidney damage.

Background and Objective: Acute kidney injury (AKI) is a complication of sepsis. Pyroptosis of gasdermin D (GSDMD)-mediated tubular epithelial cells (TECs) play important roles in pathogenesis of sepsis-associated AKI. Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3), an imprinted gene involved in tumorigenesis, is implicated in pyroptosis occurring in multiple organs. Herein, we investigated the role and mechanisms of MEG3 in regulation of TEC pyroptosis in lipopolysaccharide (LPS)-induced AKI.Materials and Methods: Male C57BL/6 mice and primary human TECs were treated with LPS for 24 h to establish the animal and cell models, respectively, of sepsis-induced AKI. Renal function was assessed by evaluation of serum creatinine and urea levels. Renal tubule injury score was assessed by Periodic acid-Schiff staining. Renal pyroptosis was assessed by evaluating expression of caspase-1, GSDMD, and inflammatory factors IL-1β and IL-18. Cellular pyroptosis was assessed by analyzing the release rate of LDH, expression of IL-1β, IL-18, caspase-1, and GSDMD, and using EtBr and EthD2 staining. MEG3 expression in renal tissues and cells was detected using RT-qPCR. The molecular mechanisms of MEG3 in LPS-induced AKI were assessed through bioinformatics analysis, RNA-binding protein immunoprecipitation, dual luciferase reporter gene assays, and a rescue experiment.Results: Pyroptosis was detected in both LPS-induced animal and cell models, and the expression of MEG3 in these models was significantly up-regulated. MEG3-knockdown TECs treated with LPS showed a decreased number of pyroptotic cells, down-regulated secretion of LDH, IL-1β, and IL-18, and decreased expression of GSDMD, compared with those of controls; however, there was no difference in the expression of caspase-1 between MEG3 knockdown cells and controls. Bioinformatics analysis screened out miR-18a-3P, and further experiments demonstrated that MEG3 controls GSDMD expression by acting as a ceRNA for miR-18a-3P to promote TECs pyroptosis.Conclusion: Our study demonstrates that lncRNA MEG3 promoted renal tubular epithelial pyroptosis by regulating the miR-18a-3p/GSDMD pathway in LPS-induced AKI.

One of the important mechanisms of diabetic nephropathy is the production of reactive oxidative species (ROS). Calycosin as an herbal compound with many medicinal uses from ancient times is the major active component of Radix astragali. In the present study, the protective effects of calycosin against high glucose (HG)-induced oxidative stress in renal tubular epithelial cells (NRK-52E) were assessed by different cellular assays. It was indicated that calycosin recovered the viability and membrane damage of cells exposed to HG through reduction in the ROS generation, and lipid peroxidation. Moreover, it was seen that calycosin resulted in a significant increase in the expression of (sirtuin-3) SIRT-3/superoxide dismutase2 (SOD2) at both mRNA and protein levels in HG‐treated cells. Also, it was determined that calysocin increased the activity of SOD2 and SIRT-3 and reduced the activity of caspase-3 in NRK-52E incubated with HG and these antioxidative and antiapoptotic effects were inhibited in the presence of 3-TYP. These results demonstrated that calycosin can prevent the cytotoxicity induced by HG in NRK-52E through regulation of SIRT-3/SOD2 pathway and it could be used as a potential candidate in the treatment of diabetic nephropathy.

Abstract Background Blood transfusion, a common basic supporting therapy, can lead to acute hemolytic transfusion reaction (AHTR). AHTR poses a great risk to patients through kidney function damage in a short time. Previous reports found that heme from destroyed red blood cells impaired kidney function, and NLR family pyrin domain containing 3 (NLRP3) inflammasome was augmented in case of kidney injury. However, the detailed mechanism regarding whether NLRP3 inflammasome is involved in kidney function injury in AHTR is not fully understood yet. Methods Hemolysis models were established by vein injection with human blood plasma or mouse heme from destroyed red blood cells. The injured renal tubular epithelial cells (RTECs) were evaluated by tubular damage markers staining in hemolysis models and in primary RTECs in vitro. The activation of NLRP3 inflammasome in RTECs by hemes was investigated by Western blot, ELISA, scanning electron microscopy, immunofluorescent staining, flow cytometry, and hemolysis models. NLRP3 gene knockout mice were employed to confirm these observations in vitro and in vivo. The binding between a novel inhibitor (66PR) and NLRP3 was affirmed by molecule docking and co‐immunoprecipitation. The rescue of 66PR on kidney function impairment was explored in murine hemolysis models. Results We found that heme could activate NLRP3 inflammasome in RTECs to induce kidney function injury. NLRP3 gene knockout could prevent the damage of RTECs caused by hemes and recover kidney function in AHTR. Moreover, NLRP3 inflammasome chemical inhibitor, 66PR, could bind to NLRP3 protein and inhibit inflammasome activation in RTECs, which consequently relieved the injury of RTECs caused by hemes, and alleviated kidney function damage in the AHTR model. Conclusions Hemes could activate NLRP3 inflammasome in RTECs, and a novel NLRP3 inflammasome inhibitor named 66PR relieved kidney function damage in AHTR. Our findings provided a new possible strategy to treat kidney function failure in AHTR.

Background and Objective: Acute kidney injury (AKI) is a complication of sepsis. Pyroptosis of gasdermin D (GSDMD)-mediated tubular epithelial cells (TECs) play important roles in pathogenesis of sepsis-associated AKI. Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3), an imprinted gene involved in tumorigenesis, is implicated in pyroptosis occurring in multiple organs. Herein, we investigated the role and mechanisms of MEG3 in regulation of TEC pyroptosis in lipopolysaccharide (LPS)-induced AKI. Materials and Methods: Male C57BL/6 mice and primary human TECs were treated with LPS for 24 h to establish the animal and cell models, respectively, of sepsis-induced AKI. Renal function was assessed by evaluation of serum creatinine and urea levels. Renal tubule injury score was assessed by Periodic acid-Schiff staining. Renal pyroptosis was assessed by evaluating expression of caspase-1, GSDMD, and inflammatory factors IL-1β and IL-18. Cellular pyroptosis was assessed by analyzing the release rate of LDH, expression of IL-1β, IL-18, caspase-1, and GSDMD, and using EtBr and EthD2 staining. MEG3 expression in renal tissues and cells was detected using RT-qPCR. The molecular mechanisms of MEG3 in LPS-induced AKI were assessed through bioinformatics analysis, RNA-binding protein immunoprecipitation, dual luciferase reporter gene assays, and a rescue experiment. Results: Pyroptosis was detected in both LPS-induced animal and cell models, and the expression of MEG3 in these models was significantly up-regulated. MEG3 -knockdown TECs treated with LPS showed a decreased number of pyroptotic cells, down-regulated secretion of LDH, IL-1β, and IL-18, and decreased expression of GSDMD, compared with those of controls; however, there was no difference in the expression of caspase-1 between MEG3 knockdown cells and controls. Bioinformatics analysis screened out miR-18a-3P, and further experiments demonstrated that MEG3 controls GSDMD expression by acting as a ceRNA for miR-18a-3P to promote TECs pyroptosis. Conclusion: Our study demonstrates that lncRNA MEG3 promoted renal tubular epithelial pyroptosis by regulating the miR-18a-3p/GSDMD pathway in LPS-induced AKI. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the role of farnesoid X receptor (FXR), a ligand‐dependent transcription factor, in renal ischaemia‐reperfusion (I/R) injury. Materials and Methods: We performed unilateral renal I/R model in FXR knockout (Fxr−/−) and wild‐type (WT) mice in vivo and a hypoxia‐reoxygenation (H/R) model in vitro. The pathways by which FXR induces apoptosis were detected using a proteome profiler array. The effects of FXR on apoptosis were evaluated using immunoblotting, TUNEL assays and flow cytometry. Results: Compared with WT mice, Fxr−/− mice showed improved renal function and reduced tubular injury scores and apoptosis. Consistent with the in vivo results, the silencing of FXR decreased the number of apoptotic HK‐2 cells after H/R, while FXR overexpression aggravated apoptosis. Notably, bone marrow transplantation (BMT) and immunohistochemistry experiments revealed the involvement of FXR in the tubular epithelium rather than in inflammatory cells. Furthermore, in vivo and in vitro studies demonstrated that FXR deficiency increased phosphorylated Bcl‐2 agonist of cell death (p‐Bad) expression levels and the ratio of Bcl‐2/Bcl‐xL to Bax expression in the kidney. Treatment with wortmannin, which reduced p‐Bad expression, inhibited the effects of FXR deficiency and eliminated the tolerance of Fxr−/− mouse kidneys to I/R injury. Conclusions: These results established the pivotal importance of FXR inactivation in tubular epithelial cells after I/R injury. FXR may promote the apoptosis of renal tubular epithelial cells by inhibiting PI3k/Akt‐mediated Bad phosphorylation to cause renal I/R damage. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is the most common complication of sepsis with a high mortality rate. In this study, we focus on the renal injury caused by the immune response of renal tubular epithelial cells and inflammation-induced renal tubular epithelial cell apoptosis. We studied the role of GRP120 in the inflammation and apoptosis of human renal cell line HK-2 and mouse primary renal tubular epithelial cells. GPR120 agonist GW9508 activated the GPR120 pathway. Inflammatory factors were detected using quantitative real-time PCR and enzyme-linked immunosorbent assay. Cell apoptosis experiments included the annexin V and PI double-staining method combined with flow cytometry, TUNEL method, and Western blot. The level of cytokines including TNF-α, IL-6, IL-1β, and iNOS was significantly decreased (P < 0.05) in HK-2 and TECs after the activation of the GPR120 pathway. Besides, the cell apoptosis of both cells increased. Overexpressed GPR120 and shGPR120 were established. Treatment with lipopolysaccharide (LPS) increased the level of cytokines including TNF-α, IL-6, IL-1β, and iNOS in HK-2 cell and TECs. Compared with control-LPS and negative control (NC)-LPS, the overexpression of GPR120 and shGPR120 could decrease and increase the level of secreted cytokines significantly (P < 0.05), respectively, after LPS-induced apoptosis. After H2O2- and LPS-induced apoptosis, respectively, compared with the control and NC groups, overexpressed GPR120 and shGPR120 could reduce and increase the expression of caspase-3, respectively. GPR120 could suppress the cellular immune response and apoptosis in renal tubular epithelial cells, thereby possibly protecting the kidney and relieving sepsis-induced AKI. [ABSTRACT FROM AUTHOR]

Background: Blood transfusion, a common basic supporting therapy, can lead to acute hemolytic transfusion reaction (AHTR). AHTR poses a great risk to patients through kidney function damage in a short time. Previous reports found that heme from destroyed red blood cells impaired kidney function, and NLR family pyrin domain containing 3 (NLRP3) inflammasome was augmented in case of kidney injury. However, the detailed mechanism regarding whether NLRP3 inflammasome is involved in kidney function injury in AHTR is not fully understood yet. Methods: Hemolysis models were established by vein injection with human blood plasma or mouse heme from destroyed red blood cells. The injured renal tubular epithelial cells (RTECs) were evaluated by tubular damage markers staining in hemolysis models and in primary RTECs in vitro. The activation of NLRP3 inflammasome in RTECs by hemes was investigated by Western blot, ELISA, scanning electron microscopy, immunofluorescent staining, flow cytometry, and hemolysis models. NLRP3 gene knockout mice were employed to confirm these observations in vitro and in vivo. The binding between a novel inhibitor (66PR) and NLRP3 was affirmed by molecule docking and co‐immunoprecipitation. The rescue of 66PR on kidney function impairment was explored in murine hemolysis models. Results: We found that heme could activate NLRP3 inflammasome in RTECs to induce kidney function injury. NLRP3 gene knockout could prevent the damage of RTECs caused by hemes and recover kidney function in AHTR. Moreover, NLRP3 inflammasome chemical inhibitor, 66PR, could bind to NLRP3 protein and inhibit inflammasome activation in RTECs, which consequently relieved the injury of RTECs caused by hemes, and alleviated kidney function damage in the AHTR model. Conclusions: Hemes could activate NLRP3 inflammasome in RTECs, and a novel NLRP3 inflammasome inhibitor named 66PR relieved kidney function damage in AHTR. Our findings provided a new possible strategy to treat kidney function failure in AHTR. [ABSTRACT FROM AUTHOR]

Mitochondrial damage in renal tubular epithelial cells (RTECs) is a hallmark of endotoxin-induced acute kidney injury (AKI). Forkhead box O1 (FOXO1) is responsible for regulating mitochondrial function and is involved in several kidney diseases. Here, we investigated the effect of FOXO1 on endotoxin-induced AKI and the related mechanism. In vivo, FOXO1 downregulation in mouse RTECs and mitochondrial damage were found in endotoxin-induced AKI. Overexpression of FOXO1 by kidney focal adeno-associated virus (AAV) delivery improved renal function and reduced mitochondrial damage. Peroxisome proliferator-activated receptor-c coactivator 1-α (PGC1-α), a master regulator of mitochondrial biogenesis and function, was reduced in endotoxin-induced AKI, but the reduction was reversed by FOXO1 overexpression. In vitro, exposure to LPS led to a decline in HK-2 cell viability, mitochondrial fragmentation, and mitochondrial superoxide accumulation, as well as downregulation of FOXO1, PGC1-α, and mitochondrial complex I/V. Moreover, overexpression of FOXO1 in HK-2 cells increased HK-2 cell viability and PGC1-α expression, and it alleviated the mitochondrial injury and superoxide accumulation induced by LPS. Meanwhile, inhibition of FOXO1 in HK-2 cells by siRNA treatment decreased PGC1-α expression and HK-2 cell viability. Chromatin immunoprecipitation assays and PCR analysis confirmed that FOXO1 bound to the PGC1-α promoter in HK-2 cells. In conclusion, downregulation of FOXO1 in RTECs mediated endotoxin-induced AKI and mitochondrial damage. Overexpression of FOXO1 could improve renal injury and mitochondrial dysfunction, and this effect occurred at least in part as a result of PGC1-a signaling. FOXO1 might be a potential target for the prevention and treatment of endotoxin-induced AKI. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to down-regulate LINC00667 and inhibit apoptosis and fibrosis of renal tubular epithelial cells through miR-34c. Methods: Altogether, 98 patients with chronic kidney disease treated in our hospital were selected as the study group, and 67 normal people were selected as the control group. Epithelial cells of proximal convoluted tubules in human renal cortex were purchased. TGF-β1 was used to induce fibrosis of HK-2 renal tubular epithelial cells. The expression of LINC00667, miR-34c, type I collagen (Col 1) and type III collagen (Col 3) were detected by qRT-PCR and WB. Results: LINC00667 was highly expressed in cancer tissues and HK-2, while miR-34c was poorly expressed. Inhibition of LINC00667 and over-expression of miR-34c could inhibit the proliferation and invasion of chronic kidney disease cells, but increase the apoptosis rate. Down-regulation of LINC00667 could significantly reduce of Col 1 and Col 3 in renal interstitial fibroblasts induced by TGF-β1, while up-regulation of miR-34c could also achieve this effect. Double luciferase report confirmed that there was a targeted regulatory relationship between LINC00667 and miR-34c. Conclusion: LINC00667 could reduce the proliferation and invasion of chronic kidney disease cells, increase the apoptosis rate by regulating miR-34c, and improve renal fibrosis. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have regenerative properties in acute kidney injury (AKI). However, the potential function of MSCs in chronic kidney disease remains elusive. Renal fibrosis is the common endpoint of chronic progressive kidney diseases and causes a considerable health burden worldwide. In this study, the protective effects of bone marrow mesenchymal stem cells (BM-MSCs) were assessed in repeated administration of low-dose cisplatin-induced renal fibrosis mouse model in vivo as well as a TGF-β1-induced fibrotic model in vitro. Differentially expressed miRNAs in mouse renal tubular epithelial cells (mRTECs) regulated by BM-MSCs were screened by high-throughput sequencing. We found microRNA (miR)-146a-5p was the most significant up-regulated miRNA in mRTECs. In addition, the gene Tfdp2 was identified as one target gene of miR-146a-5p by bioinformatics analysis. The expression of Tfdp2 in the treatment of BM-MSCs on cisplatin-induced renal injury was evaluated by immunohistochemistry analysis. Our results indicate that BM-MSC attenuates cisplatin-induced renal fibrosis by regulating the miR-146a-5p/Tfdp2 axis in mRTECs.

Acute kidney injury (AKI) is a severe kidney disease defined by partial or abrupt loss of renal function. Emerging evidence indicates that non-coding RNAs (ncRNAs), particularly long non-coding RNAs (lncRNAs), function as essential regulators in AKI development. Here we aimed to explore the underlying molecular mechanism of the lncRNA H19/miR-130a axis for the regulation of inflammation, proliferation, and apoptosis in kidney epithelial cells. Human renal proximal tubular cells (HK-2) were induced by hypoxia/reoxygenation to replicate the AKI model in vitro. After treatment, the effects of LncRNA H19 and miR-130a on proliferation and apoptosis of HK-2 cells were investigated by CCK-8 and flow cytometry. Meanwhile, the expressions of LncRNA H19, miR-130a, and inflammatory cytokines were detected by qRT-PCR, western blot, and ELISA assays. The results showed that downregulation of LncRNA H19 could promote cell proliferation, inhibit cell apoptosis, and suppress multiple inflammatory cytokine expressions in HK-2 cells by modulating the miR-130a/BCL2L11 pathway. Taken together, our findings indicated that LncRNA H19 and miR-130a might represent novel therapeutic targets and early diagnostic biomarkers for the treatment of AKI.

Trichloroethylene (TCE) induced occupational medicamentosa-like dermatitis (OMLDT) in patients is accompanied, typically, by renal damage. But the role of C5b-9 and IL-1β in TCE-sensitized mouse renal tubular damage is unclear. This study aimed to investigate whether TCE-sensitized mouse renal tubular epithelial cell damage was induced by NLRP3 inflammasome and whether NLRP3 inflammasome was activated by sublytic C5b-9. In total, 52 specific pathogen-free BALB/c female mice, 6- to 8-week-old, were used for establishing the TCE-sensitized mouse model. Renal tubular epithelial cells were isolated and used for determining the sublytic level of C5b-9. Kidney histological examination, serum neutrophil gelatinase associated lipocalin (NGAL) level were used for kidney damage evaluation. Renal protein levels of C5b-9, NLRP3, ASC, Caspase-1, IL-1β, and IL-18 were measured. The renal lesions, serum NGAL level, renal NLRP3, ASC, Caspase-1 and IL-1β protein levels all increased significantly in TCE sensitized positive group. However, pretreatment with recombinant protein sCD59-Cys inhibited the expression of C5b-9, NLRP3 inflammasome, IL-1β, IL-18, and attenuated renal tubular epithelial cell damage. The sublytic C5b-9 activated NLRP3 inflammasome and aggravated renal tubular epithelial cell damage. Pretreatment with recombinant protein sCD59-Cys blocked the expression of the NLRP3 inflammasome by inhibiting the expression of C5b-9, and alleviating renal tubular epithelial cell damage.

Objective To observe the regulatory effect of peroxisome proliferator-activated receptor γ（PPARγ） gene overexpression/silencing on the expression of necrotic apoptosis markers in the renal tubular epithelial cells （RTECs） induced by hypoxia. Methods RTECs were randomly divided into the normal control group， hypoxia injury group， overexpression group， and silence group， and the cells in the overexpression group were transfected with exogenous LV-PPARg virus overexpressing PPARγ gene； and the cells in the silence group were transfected with endogenous LV-PPARg-RNAi virus silencing PPARγ gene. When the cells grew and converged to about 70%，the cells in the normal control group were cultured in the incubator without any treatment； the cells in the hypoxia injury group， overexpression group， and silence group were placed in an anoxic chamber containing mixed gases of 95%N2 and 5%CO2，and then were cultured in sealed and hypoxic environment for 48 h. Real-time fluorescence quantitative PCR was used to detect PPARγ，receptor-interacting protein 1（RIP1），RIP3，transforming growth factor-β（TGF-β）mRNA， and Western blotting was used to detect PPARγ，RIP1，RIP3，and TGF-β protein in each group. Results Compared with the normal control group， the relative mRNA and protein expression levels of PPARγ in the hypoxia injury group， overexpression group， and silence group decreased significantly （all P<0. 05），while the relative mRNA and protein expression levels of RIP1，RIP3，and TGF-β increased significantly （all P<0. 05）；compared with the hypoxia injury group， the relative mRNA and protein expression levels of PPARγ in the overexpression group significantly increased （all P<0. 05），while the relative mRNA and protein expression levels of RIP1，RIP3，and TGF-β decreased in the overexpression group （all P<0. 05）. In the silence group， the relative mRNA and protein expression levels of PPARγ decreased significantly （both P<0. 05），while the relative mRNA and protein expression levels of RIP1，RIP3，and TGF-β increased significantly （all P<0. 05）. Conclusion In the necrotic apoptosis of RTEC induced by hypoxia， the expression of PPARγ gene decreases； overexpression of PPARγ gene can inhibit the necrotic apoptosis of RTEC induced by hypoxia， while silencing PPARγ gene can promote it. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have regenerative properties in acute kidney injury (AKI). However, the potential function of MSCs in chronic kidney disease remains elusive. Renal fibrosis is the common endpoint of chronic progressive kidney diseases and causes a considerable health burden worldwide. In this study, the protective effects of bone marrow mesenchymal stem cells (BM-MSCs) were assessed in repeated administration of low-dose cisplatin-induced renal fibrosis mouse model in vivo as well as a TGF-β1-induced fibrotic model in vitro. Differentially expressed miRNAs in mouse renal tubular epithelial cells (mRTECs) regulated by BM-MSCs were screened by high-throughput sequencing. We found microRNA (miR)-146a-5p was the most significant up-regulated miRNA in mRTECs. In addition, the gene Tfdp2 was identified as one target gene of miR-146a-5p by bioinformatics analysis. The expression of Tfdp2 in the treatment of BM-MSCs on cisplatin-induced renal injury was evaluated by immunohistochemistry analysis. Our results indicate that BM-MSC attenuates cisplatin-induced renal fibrosis by regulating the miR-146a-5p/Tfdp2 axis in mRTECs. [ABSTRACT FROM AUTHOR]

Significant cellular morphology changes in renal tubules were observed in diabetes patients and animal models. However, the interaction between insulin and tubular epithelial cells microvillar structure remains obscure. To understand microvillar dynamics, we used Scanning Ion Conductance Microscope to visualize microvillar in the living cell. Here, we found two layers of microvilli on the tubular epithelial cell surface: short compact microvilli and netlike long microvilli. Insulin treatment could increase microvilli length and density. This process was mediated by the PI 3 K/PLCγ signaling pathway, other than the PI 3 K/Arp2/3 signal pathway. In conclusion, our findings present a novel insulin signaling transduction mechanism, which contributes to understanding renal tubular epithelial cell microvilli dynamic regulation. • Short compact microvilli and netlike long microvilli presented on the tubular epithelial cell surface. • Insulin treatment increased the density and length of netlike long microvilli. • The mechanism was mediated by the activation of PI3K/PLCγ, other than the PI3K/Arp2/3 signal pathway. [ABSTRACT FROM AUTHOR]

This work aims to investigate the role of simvastatin (SIM) in renal tubular epithelial cells (HK-2) proliferation. The apoptosis model of HK-2 cells induced by high glucose was established; HK-2 cells were cultured in vitro and randomly divided into control group, model group, SIM low-dose group, SIM medium-dose group and SIM high-dose group. After 24 h culture, the inhibitory effect of SIM on high glucose-induced proliferation of HK-2 cells was evaluated by MTT method. The expression of cysteinyl aspartate specific proteinase (Caspase-3) in apoptosisrelated protein was evaluated by Western blotting; miR-92a expression in HK-2 cells was measured by RT-qPCR. High glucose group had significantly lower HK-2 cell survival rate than the control group (p<0.05); SIM middle-dose and high-dose groups had higher HK-2 cell survival rate than the model group, (p<0.05); SIM low, medium and high-dose groups had lower HK-2 cell apoptosis rate, Caspase-3 protein and miR-92a expression levels than the model group (p<0.05), all showing dose-dependence. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is a disorder that causes changes in both the structure and function of the kidneys, causing complications such as hypertension, edema, and oliguria. Renal fibrosis is also a common pathological feature of CKD. Matrix metalloproteinases (MMPs) are endopeptidases that degrade extracellular matrix (ECM) proteins. The proteinase domain consists of a zinc ion in the active site, which contributes to its stabilization with another zinc and three calcium structural ions. Many cellular processes are controlled by MMPs, such as cell-cell interactions and various signaling pathways, while they are also involved in degrading substrates on cell surfaces. Tissue inhibitors of metalloproteinases (TIMPs) are key regulators of metalloproteinases, and both are involved in regulating cell turnover, the regulation, and the progression of fibrosis and apoptosis in the tissue. MMPs play a role in renal fibrosis, such as the tubular cell epithelial-mesenchymal transition (TEM), activation of resident fibroblasts, endothelial-mesenchymal transition (EndoMT), and pericyte-myofibroblast transdifferentiation. This review aims to show the mechanisms through which MMPs contribute to renal fibrosis, paying particular attention to MMP-9 and the epithelial-mesenchymal transition., Competing Interests: The authors declare no conflict of interest. Raffaele Serra is serving as one of the Editorial Board members of this journal. We declare that Raffaele Serra had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to Amancio Carnero Moya., (© 2024 The Author(s). Published by IMR Press.)

Acute kidney injury (AKI), a condition associated with reactive oxygen species (ROS), causes high mortality in clinics annually. Active targeted antioxidative therapy is emerging as a novel strategy for AKI treatment. In this study, we developed a polymeric prodrug that targets the highly expressed Megalin receptor on proximal tubule cells, enabling direct delivery of N-Acetylcysteine (NAC) for the treatment of ischemia reperfusion injury (IRI)-induced AKI. We conjugated NAC with low molecular weight chitosan (LMWC), a biocompatible and biodegradable polymer consisting of glucosamine and N-acetylglucosamine, to enhance its internalization by tubular epithelial cells. Moreover, we further conjugated triphenylphosphonium (TPP), a lipophilic cation with a delocalized positive charge, to low molecular weight chitosan-NAC in order to enhance the distribution of NAC in mitochondria. Our study confirmed that triphenylphosphonium-low molecular weight chitosan-NAC (TLN) exhibits remarkable therapeutic effects on IRI-AKI mice. This was evidenced by improvements in renal function, reduction in oxidative stress, mitigation of pathological progress, and decreased levels of kidney injury molecule-1. These findings suggested that the polymeric prodrug TLN holds promising potential for IRI-AKI treatment., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Jing Liang reports financial support was provided by Nature Science Foundation of Zhejiang province. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Dyslipidemia is the most prevalent independent risk factor for patients with chronic kidney disease (CKD). Lipid-induced NLRP3 inflammasome activation in kidney-resident cells exacerbates renal injury by causing sterile inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that modulates the cellular redox balance; however, the exact role of Nrf2 signaling and its regulation of the NLRP3 inflammasome in hyperlipidemia-induced kidney injury are poorly understood. In this study, we demonstrated that activation of the mtROS-NLRP3 inflammasome pathway is a critical contributor to renal tubular epithelial cell (RTEC) apoptosis under hyperlipidemia. In addition, the Nrf2/ARE signaling pathway is activated in renal tubular epithelial cells under hyperlipidemia conditions both in vivo and in vitro , and Nrf2 silencing accelerated palmitic acid (PA)-induced mtROS production, mitochondrial injury, and NLRP3 inflammasome activation. However, the activation of Nrf2 with tBHQ ameliorated mtROS production, mitochondrial injury, NLRP3 inflammasome activation, and cell apoptosis in PA-induced HK-2 cells and in the kidneys of HFD-induced obese rats. Furthermore, mechanistic studies showed that the potential mechanism of Nrf2-induced NLRP3 inflammasome inhibition involved reducing mtROS generation. Taken together, our results demonstrate that the Nrf2/ARE signaling pathway attenuates hyperlipidemia-induced renal injury through its antioxidative and anti-inflammatory effects through the downregulation of mtROS-mediated NLRP3 inflammasome activation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jiang, Liu, Xia, Gan, Ren and Du.)

Objective To explore the effect and the possible mechanism of albumin on transdifferentiation of renal tubular epithelial cells. Methods The renal tubular epithelial cells (HK-2 cells) in the logarithmic phase were treated with human serum albumin (HSA) 5 mg/mL for 24 h. The expression of kidney injury molecule-1 (KIM-1), E-cadherin, α-smooth muscle actin (α-SMA), p-p38 and p38 proteins before and after HSA treatment was detected by Western blotting. Next, the HK-2 cells were divided into two groups: KIM-1 silencing group and empty vector control group, which were transfected with KIM-1 siRNA plasmid or empty vector, respectively, then the expression of E-cadherin, α-SMA and KIM-1 was detected after treatment with HSA 5 mg/mL for 24 h. At last, the HK-2 cells were divided into three groups:SB203580 + KIM-1 group, KIM-1 group, and HSA group. The cells in the SB203580 + KIM-1 group were transfected with KIM-1 overexpression plasmid for 48 h and then were pretreated with 10 μmol/L SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (MAPK) for 1 h. The cells in the KIM-1 group were only transfected with KIM-1 overexpression plasmid for 48 h. The expression of E-cadherin, α-SMA, KIM-1, p-p38 and p38 proteins in the above three groups was detected by Western blotting after treatment with HSA 5 mg/mL for 24 h. Results The protein expression of E-cadherin decreased, α-SMA, KIM-1, and p-p38 increased in HK-2 cells treated with 5 mg/mL HSA as compared with those before HSA treatment (all P ＜ 0. 05), while the change of p38 protein was statistically significant (P ＞ 0. 05). Compared with the empty vector control group, the protein expression of E-cadherin increased, α-SMA and KIM-1 decreased in the KIM-1 silencing group (all P ＜ 0. 05). In the KIM-1 group, SB203580 + KIM-1 group and HSA group, the protein expression of E-cadherin increased in turn, α-SMA and p-p38 decreased in turn (all P ＜ 0. 05), and no statistically significant difference was found in the p38 protein among three groups (P ＞ 0. 05). The protein expression of KIM-1 in the SB203580+ KIM-1 group and KIM-1 group increased as compared with that of the HSA group, while there was no statistically significant difference between the SB203580 + KIM-1 group and KIM-1 group (P ＞ 0. 05). Conclusion Albumin can promote transdifferentiation of renal tubular epithelial cells probably by promoting the expression of KIM-1 in renal tubular epithelial cells and then activating the p38 MAPK pathway. [ABSTRACT FROM AUTHOR]

Aging has become a primary cause of chronic kidney diseases, which ultimately progress to renal interstitial fibrosis. Endoplasmic reticulum (ER) stress has been reported to participate in tubular epithelial cells injury. Ginsenoside Rg1 may have protective effects on kidney aging. In this study, we investigated the tubular interstitial fibrosis and ER stress change in aged mice, and further observed the effects of Rg1 on renal interstitial fibrosis and ER stress in SAMP8 mice. The results demonstrated that the ER stress, apoptosis and interstitial fibrosis were significantly increased in the tubular epithelial cells in 20-month-old (M) and 24M mice. Meanwhile, we found that Rg1 significantly attenuated the tubular epithelial cells ER stress, apoptosis and interstitial fibrosis in SAMP8 mice. This study suggested that ER stress and apoptosis were closely implicated with aging-related renal interstitial fibrosis in aging progression. Rg1 could ameliorate aging-related renal interstitial fibrosis via inhibiting ER stress and apoptosis.

Systemic lupus erythematosus (SLE) is a systemic, autoimmune disease that can involve virtually any organ of the body. Lupus nephritis (LN), the clinical manifestation of this disease in the kidney, is one of the most common and severe outcomes of SLE. Although a key pathological hallmark of LN is glomerular inflammation and damage, tubulointerstitial lesions have been recognized as an important component in the pathology of LN. Renal tubular epithelial cells are resident cells in the tubulointerstitium that have been shown to play crucial roles in various acute and chronic kidney diseases. In this context, recent progress has been made in examining the functional role of tubular epithelial cells in LN pathogenesis. This review summarizes recent advances in our understanding of renal tubular epithelial cells in LN, the potential role of tubular epithelial cells as biomarkers in the diagnosis, prognosis, and treatment of LN, and the future therapeutic potential of targeting the tubulointerstitium for the treatment of patients with LN.

Background/Aims: Evidence from our and other groups has demonstrated that zinc transporter 7 in SLC30 family (ZnT7) inhibited epithelial-to-mesenchymal transition (EMT) and apoptosis in rat peritoneal mesothelial cells (RPMCs) under high glucose (HG) concentration. In the present study, we investigated the effect of ZnT7 on EMT of renal tubular epithelial cells (RTECs) in an in vitro model of diabetic nephropathy (DN). Methods: A dual-fluorescent staining protocol was used for detection of ZnT7 in a normal rat kidney tubular epithelial cell line (NRK-52E cells). EMT was induced with HG (30 mM). NRK-52E cells were transfected with plasmids codifying for hZnT7-EGFP and interfering RNA for determination of the effect of ZnT7 over-expression and silencing, respectively. Expression of ZnT7, activation of the MAPK/ERK and TGF-β/Smad pathways were analyzed with by means of Western blot. Results: ZnT7 was localized in the perinuclear region and Golgi apparatus. In HG-induced EMT of NRK-52E cells, ZnT7 was up-regulated. Over-expression of ZnT7 led to inhibition of HG-induced EMT, while knock-down of ZnT7 increased EMT. Furthermore, knock-down of ZnT7 and increased HG-induced EMT was accompanied by activation of the MAPK/ERK and TGF-β/Smad pathways. Conclusion: The present study provides evidence that ZnT7 has a protective effect over EMT of RTECs in DN and suggests that the inhibition of HG-induced EMT may be achieved through the MAPK/ERK and TGF-β/Smad pathways. Thereby, ZnT7 could be a potential target for translation medicine and prevention program in DN.

Aims: To observe the effect of calcitriol on tubular epithelial cells apoptosis in diabetic nephropathy (DN) and to explore the possible mechanism of its renal protection. Methods: In vivo, DN rats established by streptozocin (STZ) were treated with or without calcitriol by gavage. Rats were killed at 18 weeks after treatment. In vitro, HK-2 cells were cultured in high glucose with or without 1,25-dihydroxyvitamin D3. In some experiments, P38MAPK activator anisomycin was applied to incubate HK-2 cells. Cell apoptosis was detected by TUNEL or Annexin V-FITC/PI staining with flow cytometry. Immunohistochemical staining was used to observe the expression of VDR in kidney. Protein expression of cleaved caspase-3, Bax, Bcl-2, VDR, pp38MAPK and p38MAPK was assessed by western blotting. Result: Calcitriol treatment ameliorated the severity of proteinuria and reduced renal tubular epithelial cells apoptosis in DN rats. In addition, calcitriol treatment significantly increased renal VDR expression and reduced the expression of p-p38MAPK in rats. In vitro, 1,25-dihydroxyvitamin D3 decreased the apoptotic rate of HK-2 cells induced by high glucose. In accord with the results from animal study, 1,25-dihydroxyvitamin D3 increased VDR expression, but decreased p-p38MAPK expression in HK-2 cells. Moreover, P38MAPK activator anisomycin blocked the anti-apoptotic effect of 1,25-dihydroxyvitamin D3 on HK-2 cells. Conclusions: Calcitriol attenuates renal tubular cells apoptosis via VDR activation which inhibits p38MAPK signaling in DN rats. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is a common clinical syndrome associated with adverse short- and long-term sequelae. Renal tubular epithelial cell (RTEC) dysfunction and cell death are among the key pathological features of AKI. Diverse systemic and localized stress conditions such as sepsis, rhabdomyolysis, cardiac surgery, and nephrotoxic drugs can trigger RTEC dysfunction. Through an unbiased RNA inhibition screen, we recently identified cyclin-dependent kinase-like 5 (Cdkl5), also known as serine/threonine kinase-9, as a critical regulator of RTEC dysfunction associated with nephrotoxic and ischemia-associated AKI. In the present study, we examined the role of Cdkl5 in rhabdomyolysis-associated AKI. Using activation-specific antibodies and kinase assays, we found that Cdkl5 is activated in RTECs early during the development of rhabdomyolysis-associated AKI. Furthermore, we found that RTEC-specific Cdkl5 gene ablation mitigates rhabdomyolysis-associated renal impairment. In addition, the small-molecule kinase inhibitor AST-487 alleviated rhabdomyolysis-associated AKI in a Cdkl5-dependent manner. Mechanistically, we demonstrated that Cdkl5 phosphorylates the transcriptional regulator sex-determining region Y box 9 (Sox9) and suppresses its protective function under stress conditions. On the basis of these results, we propose that, by suppressing the protective Sox9- directed transcriptional program, Cdkl5 contributes to rhabdomyolysis-associated renal impairment. All together, the present study identified Cdkl5 as a critical stress-induced kinase that drives RTEC dysfunction and kidney injury linked with distinct etiologies. [ABSTRACT FROM AUTHOR]

Objective To explore the mechanism of Klotho reducing the mesenchymal transdifferentiation of renal tubular epithelial cells (HK‑2) by inhibiting the expression of microRNA (miR)‑21a‑5p in HK‑2 under high glucose conditions. Methods HK‑2 cells cultured in vitro were divided into low glucose (LG) group, high glucose (HG) group (30 mmol/L glucose), and hyperosmolar (HM) group (30 mmol/L mannitol). According to the time of high glucose stimulation, HK‑2 cells were divided into 0, 12, 24 and 48 h. According to pcDNA3.1‑Klotho/pcDNA3.1‑Vector transfection and low/high glucose stimulation, HK‑2 cells were divided into: LG group, HG group, HG+pcDNA3.1‑Vector group and HG+pcDNA3.1‑Klotho group. According to si‑Klotho/si‑Negative transfection and low/high glucose stimulation and whether adding pyrrolidine dithiocarbamate (PDTC), HK‑2 cells were divided into sixgroups: LG+si‑Klotho group, LG+si‑Negative group, LG+ si‑Klotho+PDTC group, HG+si‑Klotho group, HG+si‑Negative group and HG+si‑Klotho+PDTC group. Chromatin immunoprecipitation (CHIP) test groups included: LG+pcDNA3.1‑Vector group, HG+ pcDNA3.1‑Vector group and HG+pcDNA3.1‑Klotho group. The expression of miR‑21a‑5p was detected by real‑time polymerase chain reaction; the protein expression of Klotho, fibronectin (FN), α‑smooth actin (α‑SMA), nuclear factor kappa‑B (NF‑κB) and NF‑κB inhibitor (IκB) were evaluated by Western blot; the direct effect of NF‑κB on the promoter of miR‑21a‑5p was detected by CHIP. The t test analysis was used for comparison between two groups, and one‑way ANOVA was used for comparison among multiple groups. Results Compared with the LG group, the protein expression of Klotho in the HG group was decreased to 60.8% (P<0.05), the expression of miR‑21a‑5p was increased to 3.203 times (P<0.01), and the expression of FN and α‑SMA were increased significantly. With the prolonged time of high glucose stimulation, the expression of Klotho was gradually decreased, while the expression of miR‑21a‑5p was gradually increased, the trend was in the opposite direction (P<0.05). Compared with the LG group, the expression levels of nucleoprotein NF‑κB and miR‑21a‑5p in the HG group were increased to 2.934 times and 3.154 times (both P< 0.01) respectively; while overexpression of Klotho can reduce the expression of NF‑κB and miR‑21a‑5p to 50.18% and 49.24% (both P<0.05) of the HG group. The CHIP results showed that compared with the LG+pcDNA3.1‑Vector group, the combination of NF‑κB and miR‑21a‑5p promoter was increased to 3.121 times (1.000±0.742 vs 3.121±0.115, P<0.01) in the HG+pcDNA3.1‑vector group; while overexpression of Klotho can significantly reduce the high combination of NF‑κB and miR‑21a‑5p promoter to 54.21% (3.121±0.115 vs 1.692±0.073, P<0.01). Conclusion Klotho can reduce the mesenchymal transdifferentiation of renal tubular epithelial cells by inhibiting the binding of NF‑κB and miR‑21a‑5p promoter and reducing the expression of miR‑21a‑5p under high glucose conditions. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a systemic, autoimmune disease that can involve virtually any organ of the body. Lupus nephritis (LN), the clinical manifestation of this disease in the kidney, is one of the most common and severe outcomes of SLE. Although a key pathological hallmark of LN is glomerular inflammation and damage, tubulointerstitial lesions have been recognized as an important component in the pathology of LN. Renal tubular epithelial cells are resident cells in the tubulointerstitium that have been shown to play crucial roles in various acute and chronic kidney diseases. In this context, recent progress has been made in examining the functional role of tubular epithelial cells in LN pathogenesis. This review summarizes recent advances in our understanding of renal tubular epithelial cells in LN, the potential role of tubular epithelial cells as biomarkers in the diagnosis, prognosis, and treatment of LN, and the future therapeutic potential of targeting the tubulointerstitium for the treatment of patients with LN. [ABSTRACT FROM AUTHOR]

Abstract BACKGROUND: Canine kidney injury is characterized by the apoptosis and necrosis of renal tubular epithelial cells. Recent developments in mesenchymal stem cells and their exosomes research have shown great promise for the treatment of kidney injury in humans, rats and mice, but little research has been done on dogs. OBJECTIVE: To investigate the effects of canine adipose-derived mesenchymal stem cells and their exosomes on canine renal tubular epithelial cell injury induced by gentamicin in vitro. METHODS: Canine renal tubular epithelial cells were treated by 5 mmol/L gentamicin sulfate. Subsequently, canine adipose-derived mesenchymal stem cells and their conditional medium and exosomes were co-cultured with damaged canine renal tubular epithelial cells respectively. After 24 and 48 hours, the cell proliferation activity of each group was measured by cell counting kit-8 method, and the apoptosis rate of each group was detected by flow cytometry. Finally, Q-PCR was used to further reveal the effects of canine adipose-derived mesenchymal stem cell exosomes on PCNA, Bcl-2 and Bax genes in these cells. RESULTS AND CONCLUSION: Canine adipose-derived mesenchymal stem cells, their conditioned media, and exosomes could significantly promote proliferation and reduce apoptosis in damaged canine renal tubular epithelial cells (P < 0.05). Among them, canine adipose-derived mesenchymal stem cell exosomes worked best, which could significantly increase the expression of PCNA and Bcl-2 genes in damaged canine renal tubular epithelial cells (P < 0.05). These results suggest that canine adipose-derived mesenchymal stem cells can repair the canine renal tubular epithelial cell damage induced by gentamicin through their exosomes. [ABSTRACT FROM AUTHOR]