MicroRNA-29b Plays a Vital Role in Podocyte Injury and Glomerular Diseases through Inducing Mitochondrial Dysfunction.

Diabetic kidney disease (DKD) is becoming the most leading cause of end-stage renal disease (ESRD). Podocyte injury plays a critical role in DKD progression. Notably, mitochondrial dysfunction is crucial for podocyte injury. MicroRNAs (miRNAs) involves in various kidney diseases. Herein, we discovered miR-29b was induced in the urine of 126 patients with DKD (stage I and II), and negatively correlated with kidney function and podocyte homeostasis. Mechanically, miR-29b targeted peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a co-activator of transcription factors regulating mitochondrial biogenesis and energy metabolism. In vitro, ectopic miR-29b downregulated PGC-1α and promoted podocyte injury, while inhibition of miR-29b alleviated podocyte injury. Consistently, inhibition of miR-29b mitigated podocyte injury and preserved kidney function in ADR nephropathy and db/db mice, and overexpression of miR-29b accelerated disease. Knockout miR-29b specifically in podocyte inhibited mitochondrial dysfunction and podocyte injury. These results revealed miR-29b plays a crucial role in mitochondrial dysfunction through targeted inhibition on PGC-1α, leading to podocyte injury and DKD progression. Importantly, miR-29b could serve as a novel biomarker of podocyte injury and assists to early diagnose DKD.

Omega-3 PUFAs slow organ aging through promoting energy metabolism.

Energy metabolism disorder, mainly exhibiting the inhibition of fatty acid degradation and lipid accumulation, is highly related with aging acceleration. However, the intervention measures are deficient. Here, we reported Omega-3 polyunsaturated fatty acids (Omega-3 PUFAs), especially EPA, exerted beneficial effects on maintaining energy metabolism and lipid homeostasis to slow organ aging. As the endogenous agonist of peroxisome proliferator-activated receptor α (PPARα), Omega-3 PUFAs significantly boosted fatty acid ß-oxidation and ATP production in multiple aged organs. Consequently, Omega-3 PUFAs effectively inhibited age-related pathological changes, preserved organ function, and retarded aging process. The beneficial effects of Omega-3 PUFAs were also testified in mfat-1 transgenic mice, which spontaneously generate abundant endogenous Omega-3 PUFAs. In conclusion, our study innovatively demonstrated Omega-3 PUFAs administration in diet slow aging through promoting energy metabolism. The supplement of Omega-3 PUFAs or fat-1 transgene provides a promising therapeutic approach to promote healthy aging in the elderly.

Online-to-offline combined with problem-based learning is an effective teaching modality in the standardized residency training of nephrology.

BACKGROUND: The online-to-offline (O2O) teaching method is recognized as a new educational model that integrates network learning into offline classroom education, while problem-based learning (PBL) is a teaching modality that guides students to apply acquired theoretical knowledge to solve practical problems. However, implementing O2O combined with PBL has not been extensively explored in nephrology residency training. This study aims to explore the efficacy of O2O combined with PBL in the standardized residency training of nephrology by comparing it with the traditional lecture-based teaching (LBT). METHODS: Sixty residency trainees who participated in the standardized training of internal medicine in the nephrology department of the Second Affiliated Hospital of Zhejiang University School of Medicine were equally allocated into O2O combined with PBL (O2O/PBL) or the LBT group demographically matched. Examinations of theory, practice skills, clinical thinking and teaching satisfaction surveys were utilized to assess the teaching effects of the two groups. RESULTS: Participants from the O2O/PBL group outperformed those from the LBT group in the examination of theory (81.233 ± 9.156 vs. 75.800 ± 7.009, mean ± SEM), practice skills (104.433 ± 3.569 vs.100.316 ± 4.628, mean ± SEM) and clinical thinking (88.933 ± 4.473 vs. 86.667 ± 3.844, mean ± SEM). There was no significant difference in the teaching satisfaction between the two groups. CONCLUSION: The current study shows the positive impact of O2O combined with PBL approach on standardized residency training in nephrology without reducing teaching satisfaction.

Erratum: Exosomal miR-125b-5p deriving from mesenchymal stem cells promotes tubular repair by suppression of p53 in ischemic acute kidney injury: Erratum.

[This corrects the article DOI: 10.7150/thno.54550.].

Acetyl-CoA synthetase 2 promotes diabetic renal tubular injury in mice by rewiring fatty acid metabolism through SIRT1/ChREBP pathway.

Diabetic nephropathy (DN) is characterized by chronic low-grade renal inflammatory responses, which greatly contribute to disease progression. Abnormal glucose metabolism disrupts renal lipid metabolism, leading to lipid accumulation, nephrotoxicity, and subsequent aseptic renal interstitial inflammation. In this study, we investigated the mechanisms underlying the renal inflammation in diabetes, driven by glucose-lipid metabolic rearrangement with a focus on the role of acetyl-CoA synthetase 2 (ACSS2) in lipid accumulation and renal tubular injury. Diabetic models were established in mice by the injection of streptozotocin and in human renal tubular epithelial HK-2 cells cultured under a high glucose (HG, 30 mmol/L) condition. We showed that the expression levels of ACSS2 were significantly increased in renal tubular epithelial cells (RTECs) from the diabetic mice and human diabetic kidney biopsy samples, and ACSS2 was co-localized with the pro-inflammatory cytokine IL-1ß in RTECs. Diabetic ACSS2-deficient mice exhibited reduced renal tubular injury and inflammatory responses. Similarly, ACSS2 knockdown or inhibition of ACSS2 by ACSS2i (10 µmol/L) in HK-2 cells significantly ameliorated HG-induced inflammation, mitochondrial stress, and fatty acid synthesis. Molecular docking revealed that ACSS2 interacted with Sirtuin 1 (SIRT1). In HG-treated HK-2 cells, we demonstrated that ACSS2 suppressed SIRT1 expression and activated fatty acid synthesis by modulating SIRT1-carbohydrate responsive element binding protein (ChREBP) activity, leading to mitochondrial oxidative stress and inflammation. We conclude that ACSS2 promotes mitochondrial oxidative stress and renal tubular inflammation in DN by regulating the SIRT1-ChREBP pathway. This highlights the potential therapeutic value of pharmacological inhibition of ACSS2 for alleviating renal inflammation and dysregulation of fatty acid metabolic homeostasis in DN. Metabolic inflammation in the renal region, driven by lipid metabolism disorder, is a key factor in renal injury in diabetic nephropathy (DN). Acetyl-CoA synthetase 2 (ACSS2) is abundantly expressed in renal tubular epithelial cells (RTECs) and highly upregulated in diabetic kidneys. Deleting ACSS2 reduces renal fatty acid accumulation and markers of renal tubular injury in diabetic mice. We demonstrate that ACSS2 deletion inhibits ChREBP-mediated fatty acid lipogenesis, mitochondrial oxidative stress, and inflammatory response in RTECs, which play a major role in the progression of diabetic renal tubular injury in the kidney. These findings support the potential use of ACSS2 inhibitors in treating patients with DN.

Exosomal miR-125b-5p deriving from mesenchymal stem cells promotes tubular repair by suppression of p53 in ischemic acute kidney injury.

Mesenchymal stem cells-derived exosomes (MSC-exos) have attracted great interest as a cell-free therapy for acute kidney injury (AKI). However, the in vivo biodistribution of MSC-exos in ischemic AKI has not been established. The potential of MSC-exos in promoting tubular repair and the underlying mechanisms remain largely unknown. Methods: Transmission electron microscopy, nanoparticle tracking analysis, and western blotting were used to characterize the properties of human umbilical cord mesenchymal stem cells (hucMSCs) derived exosomes. The biodistribution of MSC-exos in murine ischemia/reperfusion (I/R) induced AKI was imaged by the IVIS spectrum imaging system. The therapeutic efficacy of MSC-exos was investigated in renal I/R injury. The cell cycle arrest, proliferation and apoptosis of tubular epithelial cells (TECs) were evaluated in vivo and in HK-2 cells. The exosomal miRNAs of MSC-exos were profiled by high-throughput miRNA sequencing. One of the most enriched miRNA in MSC-exos was knockdown by transfecting miRNA inhibitor to hucMSCs. Then we investigated whether this candidate miRNA was involved in MSC-exos-mediated tubular repair. Results:Ex vivo imaging showed that MSC-exos was efficiently homing to the ischemic kidney and predominantly accumulated in proximal tubules by virtue of the VLA-4 and LFA-1 on MSC-exos surface. MSC-exos alleviated murine ischemic AKI and decreased the renal tubules injury in a dose-dependent manner. Furthermore, MSC-exos significantly attenuated the cell cycle arrest and apoptosis of TECs both in vivo and in vitro. Mechanistically, miR-125b-5p, which was highly enriched in MSC-exos, repressed the protein expression of p53 in TECs, leading to not only the up-regulation of CDK1 and Cyclin B1 to rescue G2/M arrest, but also the modulation of Bcl-2 and Bax to inhibit TEC apoptosis. Finally, inhibiting miR-125b-5p could mitigate the protective effects of MSC-exos in I/R mice. Conclusion: MSC-exos exhibit preferential tropism to injured kidney and localize to proximal tubules in ischemic AKI. We demonstrate that MSC-exos ameliorate ischemic AKI and promote tubular repair by targeting the cell cycle arrest and apoptosis of TECs through miR-125b-5p/p53 pathway. This study provides a novel insight into the role of MSC-exos in renal tubule repair and highlights the potential of MSC-exos as a promising therapeutic strategy for AKI.

Gut microbiota dysbiosis-induced activation of the intrarenal renin-angiotensin system is involved in kidney injuries in rat diabetic nephropathy.

Some studies have shown that gut microbiota along with its metabolites is closely associated with diabetic mellitus (DM). In this study we explored the relationship between gut microbiota and kidney injuries of early diabetic nephropathy (DN) and its underlying mechanisms. Male SD rats were intraperitoneally injected with streptozotocin to induce DM. DM rats were orally administered compound broad-spectrum antibiotics for 8 weeks. After the rats were sacrificed, their blood, urine, feces, and renal tissues were harvested for analyses. We found that compared with the control rats, DM rats had abnormal intestinal microflora, increased plasma acetate levels, increased proteinuria, thickened glomerular basement membrane, and podocyte foot process effacement in the kidneys. Furthermore, the protein levels of angiotensin II, angiotensin-converting enzyme, and angiotensin II type 1 receptor in the kidneys of DM rats were significantly increased. Administration of broad-spectrum antibiotics in DM rats not only completely killed most intestinal microflora, but also significantly lowered the plasma acetate levels, inhibited intrarenal RAS activation, and attenuated kidney damage. Finally, we showed that plasma acetate levels were positively correlated with intrarenal angiotensin II protein expression (r = 0.969, P < 0.001). In conclusion, excessive acetate produced by disturbed gut microbiota might be involved in the kidney injuries of early DN through activating intrarenal RAS.

Association Between the Serum Uric Acid Level and the Severity of Coronary Artery Disease in a Retrospective Study of China Nondialysis CKD Patients.

Introduction: Hyperuricemia has been associated with increased cardiovascular events in the general population. However, the role of serum uric acid (SUA) level on the severity of coronary artery stenosis (CAS) in nondialysis chronic kidney disease (CKD) patients is obscure. Methods: We implement a retrospective cohort study of 734 patients diagnosed with stage 3-5 CKD. All selected patients underwent coronary artery angiography. The associations of SUA with the present, and severity of coronary artery disease (CAD) were analyzed. Results: Of these 734 patients, 511 patients had angiographically proven CAD. Compared with non-CAD group, the SUA level in CAD group was much higher (388.00 vs. 363.00 µmol/l, P < 0.01). After adjusting for multiple confounding factors, a multivariate logistic regression analysis demonstrated that SUA was relevant to the presence of CAD when SUA as a continuous variable. However, this relationship was not observed with SUA as a categorical variable. In a subgroup analysis for the CAD group, we found that the rates of severe CAS in the third tertile of SUA (58.6%) was higher than that in the first tertile (41.6%) (P < 0.01). Compared with the first tertile of SUA, the third tertile of SUA was an independent risk factor for severe arterial stenosis (odds ratio, OR, 1.976 [1.203-3.248]), a pattern that was recapitulated by multivariate logistic regression analysis with SUA as a continuous variable (1.002 [1.000-1.004]). Conclusions: The SUA level may serve as a predictor of the severity of CAS among nondialysis CKD patients with CAD.

Urinary levels of podocyte-derived microparticles are associated with the progression of chronic kidney disease.

BACKGROUND: Podocyte-derived microparticles (MPs) could be secreted from activated or apoptotic podocytes. An increased number of podocyte-derived MPs in the urine might reflect podocyte injury in renal diseases. This study aimed to observe the change of urinary podocyte-derived MP levels in patients with chronic kidney disease (CKD) and to further explore its correlation with the progression of CKD. METHODS: A prospective, longitudinal study was conducted in eighty patients with biopsy-proven CKD. Podocyte-derived MPs (annexin V and podocalyxin positive) were detected by flow cytometry. The number of urinary podocyte-derived MPs was analyzed to evaluate the association with biochemical measurements and pathological glomerulosclerosis assessment. Patients with idiopathic membranous nephropathy (IMN) were followed up after the six-month treatment of prednisone combined with tacrolimus to evaluate the association of urinary podocyte-derived MP levels and the remission of IMN. RESULTS: The CKD patients had higher urinary podocyte-derived MP levels compared with healthy controls (HCs). Baseline urinary levels of podocyte-derived MPs were positively correlated with 24-hour proteinuria, while were inversely correlated with the percentage of global glomerulosclerosis. The urinary podocyte-derived MPs levels had good discrimination for glomerulosclerosis [area under curve (AUC), 0.66]. The urinary podocyte-derived MPs levels in IMN patients were significantly decreased accompanied with the recovery of abnormal clinical parameters after six-month treatment. CONCLUSIONS: The urinary levels of podocyte-derived MPs were closely associated with podocyte injury and glomerulosclerosis, which could be useful for monitoring disease activity in CKD patients. Urinary podocyte-derived MPs might be a non-invasive biomarker for the evaluation of early CKD progression.

ANGPTL2 regulates autophagy through the MEK/ERK/Nrf-1 pathway and affects the progression of renal fibrosis in diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DN) is one of the most important microvascular complications of diabetes mellitus. The present study aims to explore whether angiopoietin-like protein 2 (ANGPTL2) can promote renal tissue fibrosis in DN. MATERIALS AND METHODS: Models includes diabetic SD rats induced by streptozotocin (STZ) and high glucose (HG)-stimulated HK-2 cells. qRT-PCR, western blot and immunohistochemical analysis were performed to explore ANGPTL2 expression. The renal injury and fibrosis were assessed using hematoxylin-eosin staining (H&E) and Masson trichrome staining. Immunofluorescence was conducted to detect the expression of collagen IV and LC3II. The levels of pro-inflammatory factors IL-6, -1ß, TNF-α and ANGPTL2 were assessed by an ELISA, and nitric oxide (NO) production was determined using Griess method. Protein levels of iNOS, PTEN, fibronectin (FN), collagen I, IV, p62, beclin1 and MEK/ERK/Nrf-1 pathway in DN rats and HK-2 cells were determined, respectively. RESULTS: When compared with normal rats, DN rats experienced severe renal injury and fibrosis and showed decreased LC3II and beclin1, increased PTEN, FN, collagen I and IV, p62, NO, iNOS and ANGPTL2 in kidney. The pro-inflammatory factors and ANGPTL2 were markedly elevated. Again, knockdown of ANGPTL2 caused an increase in MEK, p-ERK, Nrf-1, LC3II, beclin1, and a decrease in PTEN, FN, collagen I and IV, p62, NO, iNOS and pro-inflammatory factors of HK-2 cells. Furthermore, knockdown of MEK/ERK reversed these changes. CONCLUSION: ANGPTL2 may serve an important role in the autophagy of DN and activate MEK/ERK/Nrf-1 pathway, which may therefore have potential as a treatment to prevent renal fibrosis in DN.

The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway.

The discovery of hypoxia-inducible factor (HIF)-prolyl hydroxylase inhibitor (PHI) has revolutionized the treatment strategy for renal anemia. However, the presence of multiple transcription targets of HIF raises safety concerns regarding HIF-PHI. Here, we explored the dose-dependent effect of MK-8617 (MK), a kind of HIF-PHI, on renal fibrosis. MK was administered by oral gavage to mice for 12 wk at doses of 1.5, 5, and 12.5 mg/kg. In vitro, the human proximal tubule epithelial cell line HK-2 was treated with increasing doses of MK administration. Transcriptome profiling was performed, and fibrogenesis was evaluated. The dose-dependent biphasic effects of MK on tubulointerstitial fibrosis (TIF) were observed in chronic kidney disease mice. Accordingly, high-dose MK treatment could significantly enhance TIF. Using RNA-sequencing, combined with in vivo and in vitro experiments, we found that Krüppel-like factor 5 (KLF5) expression level was significantly increased in the proximal tubular cells, which could be transcriptionally regulated by HIF-1α with high-dose MK treatment but not low-dose MK. Furthermore, our study clarified that HIF-1α-KLF5-TGF-ß1 signaling activation is the potential mechanism of high-dose MK-induced TIF, as knockdown of KLF5 reduced TIF in vivo. Collectively, our study demonstrates that high-dose MK treatment initiates TIF by activating HIF-1α-KLF5-TGF-ß1 signaling. These findings provide novel insights into TIF induction by high-dose MK (HIF-PHI), suggesting that the safety dosage window needs to be emphasized in future clinical applications.-Li, Z.-L., Lv, L.-L., Wang, B., Tang, T.-T., Feng, Y., Cao, J.-Y., Jiang, L.-Q., Sun, Y.-B., Liu, H., Zhang, X.-L., Ma, K.-L., Tang, R.-N., Liu, B.-C. The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway.

Role of Podocyte Injury in Glomerulosclerosis.

Finding new therapeutic targets of glomerulosclerosis treatment is an ongoing quest. Due to a living environment of various stresses and pathological stimuli, podocytes are prone to injuries; moreover, as a cell without proliferative potential, loss of podocytes is vital in the pathogenesis of glomerulosclerosis. Thus, sufficient understanding of factors and underlying mechanisms of podocyte injury facilitates the advancement of treating and prevention of glomerulosclerosis. The clinical symptom of podocyte injury is proteinuria, sometimes with loss of kidney functions progressing to glomerulosclerosis. Injury-induced changes in podocyte physiology and function are actually not a simple passive process, but a complex interaction of proteins that comprise the anatomical structure of podocytes at molecular levels. This chapter lists several aspects of podocyte injuries along with potential mechanisms, including glucose and lipid metabolism disorder, hypertension, RAS activation, micro-inflammation, immune disorder, and other factors. These aspects are not technically separated items, but intertwined with each other in the pathogenesis of podocyte injuries.

Publisher Correction: Inflammation-activated CXCL16 pathway contributes to tubulointerstitial injury in mouse diabetic nephropathy.

The REFERENCES 1-35 are wrong because of the error in the process of typesetting.

Bioinformatics-based discovery of the urinary BBOX1 mRNA as a potential biomarker of diabetic kidney disease.

BACKGROUND: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease (ESKD) in the world. Emerging evidence has shown that urinary mRNAs may serve as early diagnostic and prognostic biomarkers of DKD. In this article, we aimed to first establish a novel bioinformatics-based methodology for analyzing the "urinary kidney-specific mRNAs" and verify their potential clinical utility in DKD. METHODS: To select candidate mRNAs, a total of 127 Affymetrix microarray datasets of diabetic kidney tissues and other tissues from humans were compiled and analyzed using an integrative bioinformatics approach. Then, the urinary expression of candidate mRNAs in stage 1 study (n = 82) was verified, and the one with best performance moved on to stage 2 study (n = 80) for validation. To avoid potential detection bias, a one-step Taqman PCR assay was developed for quantification of the interested mRNA in stage 2 study. Lastly, the in situ expression of the selected mRNA was further confirmed using fluorescent in situ hybridization (FISH) assay and bioinformatics analysis. RESULTS: Our bioinformatics analysis identified sixteen mRNAs as candidates, of which urinary BBOX1 (uBBOX1) levels were significantly upregulated in the urine of patients with DKD. The expression of uBBOX1 was also increased in normoalbuminuric diabetes subjects, while remained unchanged in patients with urinary tract infection or bladder cancer. Besides, uBBOX1 levels correlated with glycemic control, albuminuria and urinary tubular injury marker levels. Similar results were obtained in stage 2 study. FISH assay further demonstrated that BBOX1 mRNA was predominantly located in renal tubular epithelial cells, while its expression in podocytes and urothelium was weak. Further bioinformatics analysis also suggested that tubular BBOX1 mRNA expression was quite stable in various types of kidney diseases. CONCLUSIONS: Our study provided a novel methodology to identify and analyze urinary kidney-specific mRNAs. uBBOX1 might serve as a promising biomarker of DKD. The performance of the selected urinary mRNAs in monitoring disease progression needs further validation.

Calcium-sensing receptor mediates interleukin-1ß-induced collagen expression in mouse collecting duct cells.

The mechanisms that underlie the profibrotic effect of interleukin (IL)-1ß are complicated and not fully understood. Recent evidence has suggested the involvement of the calcium-sensing receptor (CaSR) in tubular injury. Therefore, the current study aimed to investigate whether CaSR mediates IL-1ß-induced collagen expression in cultured mouse inner medullary collecting duct cells (mIMCD3) and to determine the possible downstream signaling effector. The results showed that IL-1ß significantly upregulated the expression of type I and III collagens in a concentration- and time-dependent manner. Moreover, CaSR was expressed in mIMCD3 cells, and its expression was increased by increasing the concentrations and times of IL-1ß treatment. Selective inhibitors (Calhex231 or NPS2143) or the siRNA of CaSR attenuated the enhanced expression of type I and III collagens. Furthermore, IL-1ß increased nuclear ß-catenin protein levels and decreased cytoplasmic ß-catenin expression in cells. In contrast, blockage of CaSR by the pharmacological antagonists or siRNA could partially attenuate such changes in the IL-1ß-induced nuclear translocation of ß-catenin. DKK1, an inhibitor of ß-catenin nuclear translocation, further inhibited the expression of type I and III collagens in cells treated with IL-1ß plus CaSR antagonist. In summary, these data demonstrated that IL-1ß-induced collagen I and III expressions in collecting duct cells might be partially mediated by CaSR and the downstream nuclear translocation of ß-catenin.

Association of lipoprotein(a) and coronary artery disease in 1003 patients with stage 3-5 chronic kidney disease undergoing coronary angiography.

AIM: Lipoprotein(a) [Lp(a)] is considered a risk factor for cardiovascular disease. However, the role of Lp(a) in chronic kidney disease (CKD) patients is not well understood. The aim of this study was to evaluate the association between Lp(a) levels and the presence of coronary artery disease (CAD) and the severity of coronary artery stenosis (CAS) in patients with stage 3-5 CKD. PATIENTS AND METHODS: We retrospectively studied patients who were diagnosed with stage 3-5 CKD and underwent coronary artery angiography in Zhongda Hospital. The Gensini scoring system was used to assess the severity of coronary stenosis. RESULTS: A total of 1003 patients were enrolled in this cross-sectional study, and 776 of these patients were diagnosed with CAD. The Lp(a) levels were significantly higher in the CAD group than the non-CAD group [271.50 (168.00-459.25) vs. 195.00 (131.00-347.00) mg/l, P<0.001]. Multivariate logistic regression analysis showed that the Lp(a) tertiles were associated independently with the presence of CAD [tertile 2 vs. tertile 1 [adjusted odds ratio (OR)=2.063, 95% confidence interval (CI): 1.394-3.053, P<0.001] and tertile 3 vs. tertile 1 (adjusted OR=2.022, 95% CI: 1.345-3.040, P=0.001)]. After adjusting for potential confounders, the Lp(a) levels were associated independently with severe CAS [tertile 2 vs. tertile 1 (adjusted OR=1.603, 95% CI: 1.040-2.472, P=0.033); tertile 3 vs. tertile 1 (adjusted OR=1.743, 95% CI: 1.128-2.693, P=0.012)]. CONCLUSION: Higher Lp(a) levels were associated the presence of CAD and the severe CAS among patients with stage 3-5 CKD independently.

Platelet microparticles contribute to aortic vascular endothelial injury in diabetes via the mTORC1 pathway.

Platelet microparticles (PMPs) are closely associated with diabetic macrovascular complications. The present study aimed to investigate the effects of PMPs in diabetes on aortic vascular endothelial injury and to explore the underlying mechanisms. Peritoneal injection of streptozotocin was used to generate a diabetic rat model in vivo, and human umbilical vein endothelial cells (HUVECs) treated with PMPs were used in vitro. PMP levels in the circulation and aorta tissues were time-dependently increased in streptozotocin-induced diabetic rats at weeks 4, 8, and 12 (P < 0.05). Aspirin significantly inhibited the PMP levels at each time point (P < 0.05). In diabetic rats, the endothelial nitric oxide levels were decreased significantly combined with increased endothelial permeability. PMPs were internalized by HUVECs and primarily accumulated around the nuclei. PMPs inhibited endothelial nitric oxide levels to about 50% and caused approximately twofold increase in reactive oxygen species production. Furthermore, PMPs significantly decreased the endothelial glycocalyx area and expression levels of glypican-1 and occludin (P < 0.05). Interestingly, the PMP-induced endothelial injuries were prevented by raptor siRNA and rapamycin. In conclusion, increased PMPs levels contribute to aortic vascular endothelial injuries in diabetes through activating the mTORC1 pathway.

Artemisinin attenuates tubulointerstitial inflammation and fibrosis via the NF-κB/NLRP3 pathway in rats with 5/6 subtotal nephrectomy.

Artemisinin (Art) is isolated from Artemisia annua L. and known as the most effective antimalaria drugs. Previous studies demonstrated that it could exert an immune-regulatory effect on autoimmune diseases. In this study, we first investigated its potential role in tubulointerstitial inflammation and fibrosis in rats with 5/6 nephrectomy. Subtotal nephrectomized (SNx) rats were orally administered Art (100 mg·kg -1 ·d - 1) for 16 weeks. Blood and urine samples were collected for biochemical examination. Kidney tissues were collected for immunohistochemistry and Western blot analyses. Ang II-induced injury of the human kidney 2 (HK-2) cells was used for in vitro study. It was shown that Art could significantly attenuate the renal function decline in SNx rats compared with control. More importantly, Art treatment significantly reduced the tubulointerstitial inflammation and fibrosis, as demonstrated by the evaluation of renal pathology. Furthermore, Art inhibited the activation of NLRP3 inflammasome and NF-κB in the kidneys. In in vitro study, Art pretreatment could significantly prevent the activation of NLRP3 inflammasome and NF-κB in Ang II-treated HK-2 cells, while BAY11-7082 (an inhibitor of NF-κB) significantly inhibited Ang II-induced NLRP3 inflammasome activation. This study suggested that Art could provide renoprotective role by attenuating the tubulointerstitial inflammation and fibrosis in SNx rats by downregulating the NF-κB/NLRP3 signaling pathway.

Integrative Bioinformatics Analysis Provides Insight into the Molecular Mechanisms of Chronic Kidney Disease.

BACKGROUND/AIMS: Chronic kidney disease (CKD) is a worldwide public health problem. Regardless of the underlying primary disease, CKD tends to progress to end-stage kidney disease, resulting in unsatisfactory and costly treatment. Its common pathogenesis, however, remains unclear. The aim of this study was to provide an unbiased catalog of common gene-expression changes of CKD and reveal the underlying molecular mechanism using an integrative bioinformatics approach. METHODS: We systematically collected over 250 Affymetrix microarray datasets from the glomerular and tubulointerstitial compartments of healthy renal tissues and those with various types of established CKD (diabetic kidney disease, hypertensive nephropathy, and glomerular nephropathy). Then, using stringent bioinformatics analysis, shared differentially expressed genes (DEGs) of CKD were obtained. These shared DEGs were further analyzed by the gene ontology (GO) and pathway enrichment analysis. Finally, the protein-protein interaction networks(PINs) were constructed to further refine our results. RESULTS: Our analysis identified 176 and 50 shared DEGs in diseased glomeruli and tubules, respectively, including many transcripts that have not been previously reported to be involved in kidney disease. Enrichment analysis also showed that the glomerular and tubulointerstitial compartments underwent a wide range of unique pathological changes during chronic injury. As revealed by the GO enrichment analysis, shared DEGs in glomeruli were significantly enriched in exosomes. By constructing PINs, we identified several hub genes (e.g. OAS1, JUN, and FOS) and clusters that might play key roles in regulating the development of CKD. CONCLUSION: Our study not only further reveals the unifying molecular mechanism of CKD pathogenesis but also provides a valuable resource of potential biomarkers and therapeutic targets.

Inflammation-activated CXCL16 pathway contributes to tubulointerstitial injury in mouse diabetic nephropathy.

Inflammation and lipid disorders play crucial roles in synergistically accelerating the progression of diabetic nephropathy (DN). In this study we investigated how inflammation and lipid disorders caused tubulointerstitial injury in DN in vivo and in vitro. Diabetic db/db mice were injected with 10% casein (0.5 mL, sc) every other day for 8 weeks to cause chronic inflammation. Compared with db/db mice, casein-injected db/db mice showed exacerbated tubulointerstitial injury, evidenced by increased secretion of extracellular matrix (ECM) and cholesterol accumulation in tubulointerstitium, which was accompanied by activation of the CXC chemokine ligand 16 (CXCL16) pathway. In the in vitro study, we treated HK-2 cells with IL-1ß (5 ng/mL) and high glucose (30 mmol/L). IL-1ß treatment increased cholesterol accumulation in HK-2 cells, leading to greatly increased ROS production, ECM protein expression levels, which was accompanied by the upregulated expression levels of proteins in the CXCL16 pathway. In contrast, after CXCL16 in HK-2 cells was knocked down by siRNA, the IL-1ß-deteriorated changes were attenuated. In conclusion, inflammation accelerates renal tubulointerstitial lesions in mouse DN via increasing the activity of CXCL16 pathway.