KIM-1 augments hypoxia-induced tubulointerstitial inflammation through uptake of small extracellular vesicles by tubular epithelial cells.

Tubular epithelial cells (TECs) exposed to hypoxia incite tubulointerstitial inflammation (TII), while the exact mechanism is unclear. In this study, we identified that hypoxia evoked tubule injury as evidenced by tubular hypoxia-inducible factor-1α and kidney injury molecule-1 (KIM-1) expression and that renal small extracellular vesicle (sEV) production was increased with the development of TII after ischemia-reperfusion injury (IRI). Intriguingly, KIM-1-positive tubules were surrounded by macrophages and co-localized with sEVs. In vitro, KIM-1 expression and sEV release were increased in hypoxic TECs and the hypoxia-induced inflammatory response was ameliorated when KIM-1 or Rab27a, a master regulator of sEV secretion, was silenced. Furthermore, KIM-1 was identified to mediate hypoxic TEC-derived sEV (Hypo-sEV) uptake by TECs. Phosphatidylserine (PS), a ligand of KIM-1, was present in Hypo-sEVs as detected by nanoflow cytometry. Correspondingly, the inflammatory response induced by exogenous Hypo-sEVs was attenuated when KIM-1 was knocked down. In vivo, exogenous-applied Hypo-sEVs localized to KIM-1-positive tubules and exacerbated TII in IRI mice. Our study demonstrated that KIM-1 expressed by injured tubules mediated sEV uptake via recognizing PS, which participated in the amplification of tubule inflammation induced by hypoxia, leading to the development of TII in ischemic acute kidney injury.

Tubular TMEM16A promotes tubulointerstitial fibrosis by suppressing PGC-1α-mediated mitochondrial homeostasis in diabetic kidney disease.

Tubulointerstitial fibrosis (TIF) plays a crucial role in the progression of diabetic kidney disease (DKD). However, the underlying molecular mechanisms remain obscure. The present study aimed to examine whether transmembrane member 16A (TMEM16A), a Ca2+-activated chloride channel, contributes to the development of TIF in DKD. Interestingly, we found that TMEM16A expression was significantly up-regulated in tubule of murine model of DKD, which was associated with development of TIF. In vivo inhibition of TMEM16A channel activity with specific inhibitors Ani9 effectively protects against TIF. Then, we found that TMEM16A activation induces tubular mitochondrial dysfunction in in vivo and in vitro models, with the evidence of the TMEM16A inhibition with specific inhibitor. Mechanically, TMEM16A mediated tubular mitochondrial dysfunction through inhibiting PGC-1α, whereas overexpression of PGC-1α could rescue the changes. In addition, TMEM16A-induced fibrogenesis was dependent on increased intracellular Cl-, and reducing intracellular Cl- significantly blunted high glucose-induced PGC-1α and profibrotic factors expression. Taken together, our studies demonstrated that tubular TMEM16A promotes TIF by suppressing PGC-1α-mediated mitochondrial homeostasis in DKD. Blockade of TMEM16A may serve as a novel therapeutic approach to ameliorate TIF.

Long noncoding RNA SNHG5 promotes podocyte injury via the microRNA-26a-5p/TRPC6 pathway in diabetic nephropathy.

Podocyte injury is a characteristic pathological hallmark of diabetic nephropathy (DN). However, the exact mechanism of podocyte injury in DN is incompletely understood. This study was conducted using db/db mice and immortalized mouse podocytes. High-throughput sequencing was used to identify the differentially expressed long noncoding RNAs in kidney of db/db mice. The lentiviral shRNA directed against long noncoding RNA small nucleolar RNA host gene 5 (SNHG5) or microRNA-26a-5p (miR-26a-5p) agomir was used to treat db/db mice to regulate the SNHG5/miR-26a-5p pathway. Here, we found that the expression of transient receptor potential canonical type 6 (TRPC6) was significantly increased in injured podocytes under the condition of DN, which was associated with markedly decreased miR-26a-5p. We determined that miR-26a-5p overexpression ameliorated podocyte injury in DN via binding to 3'-UTR of Trpc6, as evidenced by the markedly reduced activity of luciferase reporters by miR-26a-5p mimic. Then, the upregulated SNHG5 in podocytes and kidney in DN was identified, and it was proved to sponge to miR-26a-5p directly using luciferase activity, RNA immunoprecipitation, and RNA pull-down assay. Knockdown of SNHG5 attenuated podocyte injury in vitro, accompanied by an increased expression of miR-26a-5p and decreased expression of TRPC6, demonstrating that SNHG5 promoted podocyte injury by controlling the miR-26a-5p/TRPC6 pathway. Moreover, knockdown of SNHG5 protects against podocyte injury and progression of DN in vivo. In conclusion, SNHG5 promotes podocyte injury via the miR-26a-5p/TRPC6 pathway in DN. Our findings provide novel insights into the pathophysiology of podocyte injury and a potential new therapeutic strategy for DN.

Quercetin alleviates tubulointerstitial inflammation by inhibiting exosomes-mediated crosstalk between tubular epithelial cells and macrophages.

BACKGROUND: Tubulointerstitial inflammation (TII) is a critical pathological feature of kidney disease leading to renal fibrosis, and its treatment remains a major clinical challenge. We sought to explore the role of quercetin, a potential exosomes inhibitor, in exosomes release and TII. METHODS: The effects of quercetin on exosomes release and TII were examined by two TII mouse models: the unilateral ureteral obstruction (UUO) models and the LPS-induced mouse models. In vitro, exosomes-mediated crosstalk between tubular epithelial cells (TECs) and macrophages was performed to investigate the mechanisms by which quercetin inhibited exosomes and TII. RESULTS: In this study, we found that exosomes-mediated crosstalk between TECs and macrophages contributed to the development of TII. In vitro, exosomes released from LPS-stimulated TECs induced increased expression of inflammatory cytokines and fibrotic markers in Raw264·7 cells and vice versa. Interestingly, heat shock protein 70 (Hsp70) or Hsp90 proteins could control exosomes release from TECs and macrophages both in vivo and in vitro. Importantly, quercetin, a previously recognized heat shock protein inhibitor, could significantly reduce exosomes release in TII models by down-regulating Hsp70 or Hsp90. Quercetin abrogated exosomes-mediated intercellular communication, which attenuated TII and renal fibrosis accordingly. CONCLUSION: Quercetin could serve as a novel strategy for treatment of tubulointerstitial inflammation by inhibiting the exosomes-mediated crosstalk between tubules and macrophages.

Satellite cell-derived exosome-mediated delivery of microRNA-23a/27a/26a cluster ameliorates the renal tubulointerstitial fibrosis in mouse diabetic nephropathy.

Renal tubulointerstitial fibrosis (TIF) is considered as the final convergent pathway of diabetic nephropathy (DN) without effective therapies currently. MiRNAs play a key role in fibrotic diseases and become promising therapeutic targets for kidney diseases, while miRNA clusters, formed by the cluster arrangement of miRNAs on chromosomes, can regulate diverse biological functions alone or synergistically. In this study, we developed clustered miR-23a/27a/26a-loaded skeletal muscle satellite cells-derived exosomes (Exos) engineered with RVG peptide, and investigated their therapeutic efficacy in a murine model of DN. Firstly, we showed that miR-23a-3p, miR-26a-5p and miR-27a-3p were markedly decreased in serum samples of DN patients using miRNA sequencing. Meanwhile, we confirmed that miR-23a-3p, miR-26a-5p and miR-27a-3p were primarily located in proximal renal tubules and highly negatively correlated with TIF in db/db mice at 20 weeks of age. We then engineered RVG-miR-23a/27a/26a cluster loaded Exos derived from muscle satellite cells, which not only enhanced the stability of miR-23a/27a/26a cluster, but also efficiently delivered more miR-23a/27a/26a cluster homing to the injured kidney. More importantly, administration of RVG-miR-23a/27a/26a-Exos (100 µg, i.v., once a week for 8 weeks) significantly ameliorated tubular injury and TIF in db/db mice at 20 weeks of age. We revealed that miR-23a/27a/26a-Exos enhanced antifibrotic effects by repressing miRNA cluster-targeting Lpp simultaneously, as well as miR-27a-3p-targeting Zbtb20 and miR-26a-5p-targeting Klhl42, respectively. Knockdown of Lpp by injection of AAV-Lpp-RNAi effectively ameliorated the progression of TIF in DN mice. Taken together, we established a novel kidney-targeting Exo-based delivery system by manipulating the miRNA-23a/27a/26a cluster to ameliorate TIF in DN, thus providing a promising therapeutic strategy for DN.

Combined transabdominal and transvaginal ultrasound-guided percutaneous microwave ablation of uterine myomas: an effective monitoring technique.

OBJECTIVE: This study compared the feasibility and efficacy of transabdominal ultrasound (TAU) and combined transabdominal and transvaginal ultrasound (TA/TV US)-guided percutaneous microwave ablation (PMWA) for uterine myoma (UM). METHOD: This study enrolled 73 patients with UM who underwent PMWA via the transabdominal ultrasound-guided (TA group) or the combined transabdominal and transvaginal ultrasound-guided (TA/TV group) approaches. The intraoperative supplementary ablation rates, postoperative immediate ablation rates, lesion reduction rates and other indicators three months postoperatively were compared between the groups. The display of the needle tip, endometrium, uterine serosa, rectum and myoma feeding vessels under the guidance of TAU, transvaginal ultrasound (TVU) and TA/TV US were evaluated in the TA/TV group. RESULTS: In the TA/TV group, the real-time position of the needle tip and the endometrium complete display rate of the same lesions with TVU guidance were significantly higher than those using TAU. TA/TV US guidance significantly improved the complete display rate of each indicator. The intraoperative supplementary ablation rate in the TA/TV group was lower than that in the TA group. Similarly, the postoperative immediate ablation and volume reduction rates of the lesions three months postoperatively were higher than those in the TA group, especially for lesions with a maximum diameter ≥6 cm. CONCLUSION: TA/TV US is an effective monitoring method that can be used to improve imaging display. Its use is recommended in patients with obesity, poor transabdominal ultrasound image quality and large myoma volumes.

Tubular-specific CDK12 knockout causes a defect in urine concentration due to premature cleavage of the slc12a1 gene.

Cyclin-dependent kinase 12 (CDK12) plays a critical role in regulating gene transcription. CDK12 inhibition is a potential anticancer therapeutic strategy. However, several clinical trials have shown that CDK inhibitors might cause renal dysfunction and electrolyte disorders. CDK12 is abundant in renal tubular epithelial cells (RTECs), but the exact role of CDK12 in renal physiology remains unclear. Genetic knockout of CDK12 in mouse RTECs causes polydipsia, polyuria, and hydronephrosis. This phenotype is caused by defects in water reabsorption that are the result of reduced Na-K-2Cl cotransporter 2 (NKCC2) levels in the kidney. In addition, CKD12 knockout causes an increase in Slc12a1 (which encodes NKCC2) intronic polyadenylation events, which results in Slc12a1 truncated transcript production and NKCC2 downregulation. These findings provide novel insight into CDK12 being necessary for maintaining renal homeostasis by regulating NKCC2 transcription, which explains the critical water and electrolyte disturbance that occurs during the application of CDK12 inhibitors for cancer treatment. Therefore, there are safety concerns about the clinical use of these new anticancer drugs.

Efficacy of Transabdominal Ultrasound-guided Percutaneous Microwave Ablation in the Treatment of Symptomatic Adenomyosis: A Retrospective Cohort Study.

STUDY OBJECTIVE: To evaluate and compare the clinical efficacy of transabdominal ultrasound-guided percutaneous microwave ablation (PMWA) in the treatment of symptomatic focal and nonfocal adenomyosis. DESIGN: Retrospective cohort study. SETTING: Longyan First Affiliated Hospital of Fujian Medical University. PATIENTS: From May 2019 to October 2021, 107 patients with symptomatic adenomyosis who refused hysterectomy received PMWA. INTERVENTIONS: Patients were divided into a focal group (n = 47, including 40 focal adenomyosis and 7 adenomyoma cases) and a nonfocal group (n = 60, including 36 diffuse and 24 mixed adenomyosis cases) according to the extent of lesion involvement. MEASUREMENTS AND MAIN RESULTS: We collected and analyzed preoperative baseline data on patient characteristics; postoperative efficacy measures at 3, 6, and 12 months; and intraoperative and postoperative complications. There was a significant post-treatment reduction in the uterine corpus volume and cancer antigen 125 levels, an increase in hemoglobin levels, and an improvement in the Uterine Fibroid Symptom and Health-related Quality of Life scores (consisting of the Symptom Severity Scale and the Health-related Quality of Life scale), dysmenorrhea visual analog scale, and menstrual volume score (MVS) (all p <.05). One patient had recurrence. Most adverse events (72.0%) were mild. Although the nonfocal group had significantly greater anemia severity, higher Symptom Severity Scale and MVS, lower Health-related Quality of Life scale, greater extent and severity of myometrial involvement, and larger uterine corpus volume, after treatment, the uterine corpus volume, uterine corpus reduction rate, cancer antigen 125 levels, hemoglobin levels, Uterine Fibroid Symptom and Health-related Quality of Life score, dysmenorrhea visual analog scale, MVS score, and clinical response rate were similar between the groups (p >.05). CONCLUSION: PMWA had good, similar, short-term efficacy for symptomatic focal and nonfocal adenomyosis.

Efficient Distributed Wireless Power Transfer System for Multiple Wearable Sensors through Textile Coil Array.

When it is necessary to detect various physiological signals of the human body, clothing embroidered with near-field effect patterns can be used as a long-term power supply medium to supply power to long-distance transmitters and receivers to form a wireless power supply system. The proposed system uses an optimized parallel circuit to achieve a power transfer efficiency of more than five times higher than that of the existing series circuit. The power transfer efficiency of simultaneously supplying energy to multiple sensors is increased higher than five times and even more when only one sensor is coupled. When powering eight sensors at the same time, the power transmission efficiency can reach 25.1%. Even when eight sensors powered by the coupled textile coils are reduced to one, the power transfer efficiency of the whole system can reach 13.21%. Additionally, the proposed system is also applicable when the number of sensors ranges from 2 to 12.

Clinical efficacy of myometrial and endometrial microwave ablation in the treatment of patients with adenomyosis who had anemia.

OBJECTIVE: This study evaluated the clinical efficacy of myometrial and endometrial microwave ablation (MEWA) for treating adenomyosis in patients with anemia. METHODS: This retrospective study enrolled 64 patients with adenomyosis who had anemia treated with either MEWA (MEWA group) or myometrial microwave ablation (MMWA group) between May 2019 and May 2021. The uterine volumes, uterine-volume reduction rates, hemoglobin (Hb) levels, cancer antigen 125 (CA125) levels, dysmenorrhea visual analog scale (VAS) scores, uterine fibroblast symptoms and health-related quality of life (UFS-QOL) scores, menstrual flow scores (MFS) before and 3, 6, and 12 months post-treatment, and adverse events and complications in both groups were collected to assess clinical efficacy. RESULTS: No statistically significant preoperative differences were observed in any measured factors. Postoperatively, there was a significant reduction in uterine volume and CA125 level, an increase in Hb level, and improvement in the UFS-QOL, dysmenorrhea VAS score, and MFS. No differences were observed in postoperative uterine volume, CA125 level, overall response rate, and adverse event rate during the follow-up period until 12 months postoperatively. However, the MEWA group showed a better uterine-volume reduction rate 6 months postoperatively and improvement in Hb level, USF-QOL score, dysmenorrhea VAS score, and MFS postoperatively. CONCLUSION: MEWA and MMWA demonstrated high clinical efficacy in treating adenomyosis and anemia. However, MEWA is a more effective therapy that successfully improves anemia, resulting in improved quality of life.

Three-dimensional ultrasound VOCAL combined with contrast-enhanced ultrasound: an alternative to contrast-enhanced magnetic resonance imaging for evaluating ablation of benign uterine lesions.

OBJECTIVE: This study explores the feasibility and value of three-dimensional ultrasound virtual organ computer-aided analysis (3D-VOCAL) combined with contrast-enhanced ultrasound (CEUS) for measuring the non-perfused volume (NPV) after microwave ablation (MWA) of benign uterine lesions. METHODS: Fifty-six patients with uterine myoma (UM) and adenomyosis (AM) treated with MWA were enrolled. NPV measurements were obtained postoperatively using two-dimensional CEUS (2D-CEUS), 3D-VOCAL combined with CEUS and three-dimensional contrast-enhanced magnetic resonance imaging (3D-CEMRI). Bland-Altman analysis and intraclass correlation coefficient (ICC) values were used to analyze the agreement of NPV measurements obtained via 2D-CEUS and the combined method with 3D-CEMRI. The inter- and intra-observer agreements of the NPV values obtained with all three methods were also analyzed. RESULTS: Considering 3D-CEMRI as the standard, 3D-VOCAL showed greater agreement than 2D-CEUS and higher ICCs (ICC, 0.999 vs. 0.891) than 2D-CEUS for different lesion types and sizes of non-perfusion areas (p < 0.001 for all comparisons). NPV measurements obtained via 2 D-CEUS and 3 D-CEMRI differed significantly for AM and non-perfusion areas with maximum diameter ≥5 cm (p < 0.05) and showed no significant differences (p > 0.05) for UM and non-perfusion areas with maximum diameter <5 cm. The NPV measurements obtained via 3D-VOCAL and 3D-CEMRI did not differ significantly (p > 0.05). The intra- and inter-observer agreements of 3D-VOCAL measurements were better than those of 2D-CEUS and slightly lower than those of 3D-CEMRI. CONCLUSIONS: 3D-VOCAL combined with CEUS provides accurate estimates of NPV after MWA of benign uterine lesions, and offers a reliable, simple and efficient alternative to CEMRI.

Association between uric acid level and contrast-induced acute kidney injury in patients with type 2 diabetes mellitus after coronary angiography: a retrospective cohort study.

BACKGROUND: This study assessed the predictive value of uric acid (UA) for contrast-induced acute kidney injury (CI-AKI) in patients with type 2 diabetes mellitus (T2DM) who underwent coronary angiography (CAG). A nomogram to aid in the prediction of CI-AKI was also developed and validated, and the construction of a prognostic nomogram combined with clinical features was attempted. METHODS: This study retrospectively enrolled T2DM patients who underwent CAG between December 2019 and December 2020 at the Affiliated Zhongda Hospital of Southeast University. Multivariable logistic regression analysis was used for the analysis of clinical outcomes. Receiver operating characteristic (ROC) analyses were performed to determine the area under the ROC curve (AUC) and the cut-off points for continuous clinical data. The prediction accuracies of models for CI-AKI were estimated through Harrell's concordance indices (C-index). Nomograms of the prognostic models were plotted for individualized evaluations of CI-AKI in T2DM patients after CAG. RESULTS: A total of 542 patients with T2DM who underwent CAG were included in this study. We found that a high UA level (≥ 425.5 µmol/L; OR = 6.303), BUN level (≥ 5.98 mmol/L; OR = 3.633), Scr level (≥ 88.5 µmol/L; OR = 2.926) and HbA1C level (≥ 7.05%; OR = 5.509) were independent factors for CI-AKI in T2DM patients after CAG. The nomogram model based on UA, BUN, Scr and HbA1C levels presented outstanding performance for CI-AKI prediction (C-index: 0.878). Decision curve analysis (DCA) showed good clinical applicability in predicting the incidence of CI-AKI in T2DM patients who underwent CAG. CONCLUSION: High UA levels are associated with an increased incidence of CI-AKI in T2DM patients after CAG. The developed nomogram model has potential predictive value for CI-AKI and might serve as an economic and efficient prognostic tool in clinical practice.

Kim-1 Targeted Extracellular Vesicles: A New Therapeutic Platform for RNAi to Treat AKI.

BACKGROUND: AKI is a significant public health problem with high morbidity and mortality. Unfortunately, no definitive treatment is available for AKI. RNA interference (RNAi) provides a new and potent method for gene therapy to tackle this issue. METHODS: We engineered red blood cell-derived extracellular vesicles (REVs) with targeting peptides and therapeutic siRNAs to treat experimental AKI in a mouse model after renal ischemia/reperfusion (I/R) injury and unilateral ureteral obstruction (UUO). Phage display identified peptides that bind to the kidney injury molecule-1 (Kim-1). RNA-sequencing (RNA-seq) characterized the transcriptome of ischemic kidney to explore potential therapeutic targets. RESULTS: REVs targeted with Kim-1-binding LTH peptide (REVLTH) efficiently homed to and accumulated at the injured tubules in kidney after I/R injury. We identified transcription factors P65 and Snai1 that drive inflammation and fibrosis as potential therapeutic targets. Taking advantage of the established REVLTH, siRNAs targeting P65 and Snai1 were efficiently delivered to ischemic kidney and consequently blocked the expression of P-p65 and Snai1 in tubules. Moreover, dual suppression of P65 and Snai1 significantly improved I/R- and UUO-induced kidney injury by alleviating tubulointerstitial inflammation and fibrosis, and potently abrogated the transition to CKD. CONCLUSIONS: A red blood cell-derived extracellular vesicle platform targeted Kim-1 in acutely injured mouse kidney and delivered siRNAs for transcription factors P65 and Snai1, alleviating inflammation and fibrosis in the tubules.

The triglyceride-glucose index as a novel marker associated with sarcopenia in non-diabetic patients on maintenance hemodialysis.

OBJECTIVE: Sarcopenia is a common complication in patients with end-stage kidney disease. Insulin resistance is present in non-diabetic patients undergoing maintenance hemodialysis (MHD) and is an important factor leading to sarcopenia. The triglyceride-glucose (TyG) index, a reliable indicator for evaluating insulin resistance, is widely used in clinical practice. The present study investigated the association between the TyG index and sarcopenia in non-diabetic patients undergoing MHD. METHODS: Relevant clinical data of non-diabetic patients undergoing MHD at our center were collected. The TyG index was calculated using the following formula: ln(fasting triglycerides(mg/dL)×fasting blood glucose(mg/dL)/2). Multivariate logistic regression analyses were used to evaluate the associations. The receiver-operating characteristic curve was used to analyze the predictive value of the TyG index in sarcopenia. RESULTS: Of the 142 patients undergoing MHD who were included, 75 (52.82%) were men, the mean age was 54.05 ± 13.97 years, and 40 (28.17%) patients satisfied the diagnostic criteria for sarcopenia. The TyG index of participants with sarcopenia was higher compared with those without sarcopenia (8.83 ± 0.45 vs. 8.49 ± 0.50, p < 0.001). The prevalence of sarcopenia increased with increasing TyG index tertile (T1, 8.51%; T2, 31.91%; T3, 43.75%; p = 0.001). Logistic regression analysis indicated that the TyG index was an independent risk factor for sarcopenia (odds ratio, 4.21 [95% confidence interval, 1.85-9.59], p = 0.001). CONCLUSION: A higher TyG index was associated with an increased risk of sarcopenia in non-diabetic patients undergoing MHD; it may be used as a novel marker to reflect the presence of sarcopenia.

HIF-1α is transcriptionally regulated by NF-κB in acute kidney injury.

Oxygen homeostasis disturbances play a critical role in the pathogenesis of acute kidney injury (AKI). The transcription factor hypoxia-inducible factor-1 (HIF-1) is a master regulator of adaptive responses to hypoxia. Aside from posttranslational hydroxylation, the mechanism of HIF-1 regulation in AKI remains largely unclear. In this study, the mechanism of HIF-α regulation in AKI was investigated. We found that tubular HIF-1α expression significantly increased at the transcriptional level in ischemia-reperfusion-, unilateral ureteral obstruction-, and sepsis-induced AKI models, which was closely associated with macrophage-dependent inflammation. Meanwhile, NF-κB, which plays a central role in the inflammation response, was involved in the increasing expression of HIF-1α in AKI, as evidenced by pharmacological modulation (NF-κB inhibitor BAY11-7082). Mechanistically, NF-κB directly bound to the HIF-1α promoter and enhanced its transcription, which occurred not only under hypoxic conditions but also under normoxic conditions. Moreover, the induced HIF-1α by inflammation protected against tubular injury in AKI. Thus, our findings not only provide novel insights into HIF-1 regulation in AKI but also offer to understand the pathophysiology of kidney diseases.NEW & NOTEWORTHY Here, the mechanism of hypoxia-inducible factor-α (HIF-α) regulation in acute kidney injury (AKI) was investigated. We found that tubular HIF-1α expression significantly increased at the transcriptional level, which was closely associated with macrophage-dependent inflammation. Meanwhile, NF-κB was involved in the increasing expression of HIF-1α in AKI. Mechanistically, NF-κB directly bound to the HIF-1α promoter and enhanced its transcription. Our findings not only provide novel insights into HIF-1 regulation in AKI but also offer to understand the pathophysiology of kidney diseases.

Identification of Lumican and Fibromodulin as Hub Genes Associated with Accumulation of Extracellular Matrix in Diabetic Nephropathy.

INTRODUCTION: Diabetic nephropathy (DN) remains a major cause of end-stage renal disease. The development of novel biomarkers and early diagnosis of DN are of great clinical importance. The goal of this study was to identify hub genes with diagnostic potential for DN by weighted gene co-expression network analysis (WGCNA). METHODS: Gene Expression Omnibus database was searched for microarray data including distinct types of CKD. Gene co-expression network was constructed, and modules specific for DN were identified by WGCNA. Gene ontology (GO) analysis was performed, and the hub genes were screened out within the selected gene modules. In addition, cross-validation was performed in an independent dataset and in samples of renal biopsies with DN and other types of glomerular diseases. RESULTS: Dataset GSE99339 was selected, and a total of 179 microdissected glomeruli samples were analyzed, including DN, normal control, and 7 groups of other glomerular diseases. Twenty-three modules of the total 10,947 genes were grouped by WGCNA, and a module was specifically correlated with DN (r = 0.54, p = 9e-15). GO analysis showed that module genes were mainly enriched in the accumulation of extracellular matrix (ECM). LUM, ELN, FBLN1, MMP2, FBLN5, and FMOD were identified as hub genes. Cross verification showed LUM and FMOD were higher in the DN group and were negatively correlated with estimated glomerular filtration rate (eGFR). In renal biopsies, expression levels of LUM and FMOD were higher in DN than IgA nephropathy, membranous nephropathy, and normal controls. CONCLUSION: By using WGCNA approach, we identified LUM and FMOD related to ECM accumulation and were specific for DN. These 2 genes may represent potential candidate diagnostic biomarkers of DN.

FIH-1-modulated HIF-1α C-TAD promotes acute kidney injury to chronic kidney disease progression via regulating KLF5 signaling.

Incomplete recovery from episodes of acute kidney injury (AKI) can predispose patients to develop chronic kidney disease (CKD). Although hypoxia-inducible factor-1α (HIF-1α) is a master regulator of the response to hypoxia/ischemia, the role of HIF-1α in CKD progression following incomplete recovery from AKI is poorly understood. Here, we investigated this issue using moderate and severe ischemia/reperfusion injury (I/RI) mouse models. We found that the outcomes of AKI were highly associated with the time course of tubular HIF-1α expression. Sustained activation of HIF-1α, accompanied by the development of renal fibrotic lesions, was found in kidneys with severe AKI. The AKI to CKD progression was markedly ameliorated when PX-478 (a specific HIF-1α inhibitor, 5 mg· kg-1·d-1, i.p.) was administered starting on day 5 after severe I/RI for 10 consecutive days. Furthermore, we demonstrated that HIF-1α C-terminal transcriptional activation domain (C-TAD) transcriptionally stimulated KLF5, which promoted progression of CKD following severe AKI. The effect of HIF-1α C-TAD activation on promoting AKI to CKD progression was also confirmed in in vivo and in vitro studies. Moreover, we revealed that activation of HIF-1α C-TAD resulted in the loss of FIH-1, which was the key factor governing HIF-1α-driven AKI to CKD progression. Overexpression of FIH-1 inhibited HIF-1α C-TAD and prevented AKI to CKD progression. Thus, FIH-1-modulated HIF-1α C-TAD activation was the key mechanism of AKI to CKD progression by transcriptionally regulating KLF5 pathway. Our results provide new insights into the role of HIF-1α in AKI to CKD progression and also the potential therapeutic strategy for the prevention of renal diseases progression.

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.

Dopamine D1 receptor agonist A68930 attenuates acute kidney injury by inhibiting NLRP3 inflammasome activation.

Renal ischemia/reperfusion (I/R) injury is a major cause of acute kidney injury (AKI), characterized by tubulointerstitial inflammation. Currently, progress in developing effective therapies to prevent or ameliorate AKI by anti-inflammation remains slow. Emerging studies have suggested that NLRP3 (the NOD-, LRR- and pyrin domain-containing 3) inflammasome plays a key role in a wide spectrum of kidney disease models including I/R injury. In this study, we investigated the renal protective effects of A68930, a specific agonist for the D-1 dopamine receptor (DRD1), which was recently recognized to downregulate NLRP3 inflammasome via DRD1 signaling. AKI was induced by renal I/R injury and A68930 was intraperitoneally injected 3 times after renal reperfusion. We showed that A68930 significantly ameliorated renal dysfunction. Meanwhile, A68930 markedly reduced macrophages and T cells infiltration, renal pro-inflammatory cytokines production (TNF-α, IL-6, IL-1ß), serum pro-inflammatory cytokine (TNF-α and IL-6) and NLRP3 inflammasome activation. Additionally, A68930 attenuated I/R-induced mitochondria injury, which was observed by transmission electron microscopy. In summary, our results demonstrated that activation of DRD1 by A68930 inhibited renal and systematic inflammation, and improved kidney function in I/R induced AKI model, which was probably related to the inhibition of the NLRP3 inflammasome activation.

MicroRNA26a inhibits cisplatin-induced renal tubular epithelial cells apoptosis through suppressing the expression of transient receptor potential channel 6 mediated dynamin-related protein 1.

Acute kidney injury (AKI) is a common adverse reaction of the anticancer drug. Among these chemotherapeutic agents, cisplatin, an effective chemotherapeutic drug, is extensively applied to the treatment of solid tumours, yet various adverse reactions, especially AKI, often limit their use. However, the pathogenesis of AKI caused by cisplatin remains poorly clarified. Therefore, we tested whether microRNAs, which have been certified as key regulators of disease are involved in this process. AKI mouse and HK2 cells were treated with cisplatin. Annexin V/PI staining and cleaved caspase-3 were used to assess apoptosis. Western blot analyses and qRT-PCR were used to evaluate the protein and mRNA level of TRPC6 and DRP1. miR-26a was remarkably decreased in cisplatin-induced AKI and in cisplatin co-cultured HK2 cells. Furthermore, we used a miR-26a mimics in vitro and found that apoptosis was alleviated than that in the control cells. We further verified that miR-26a protected against cisplatin-induced cell apoptosis by acting on transient receptor potential channel 6 (TRPC6) which can regulate the expression of dynamin-related protein 1 (DRP1), thus inhibited the mitochondrial apoptosis pathway. Therefore, the study unveiled that miR-26a/TRPC6/DRP1 is a novel protective pathway in cisplatin-induced AKI and may be targeted for the prevention and treatment of drug-related renal injury. SIGNIFICANCE OF THE STUDY: Our study found that miR-26a was significantly downregulated during cisplatin-induced AKI and during cisplatin co-cultured HK2 cells. Further, in vitro we used miR-26a mimic to intervene cells and found that apoptosis alleviated compared with control group. We further verified that miR-26a protected cisplatin-induced apoptosis by target transient receptor potential channel 6 (TRPC6) which can regulate the expression of dynamic-related protein 1 (DRP1) and inhibit the mitochondrial apoptosis pathway. Thus, miR-26a/TRPC6/DRP1 is a new protective pathway in cisplatin-induced AKI and may be targeted for the prevention and treatment of drug-related acute kidney injury.