VDR regulates mitochondrial function as a protective mechanism against renal tubular cell injury in diabetic rats.

PURPOSE: To investigate the regulatory effect and mechanism of Vitamin D receptor (VDR) on mitochondrial function in renal tubular epithelial cell under diabetic status. METHODS: The diabetic rats induced by streptozotocin (STZ) and HK-2 cells under high glocose(HG)/transforming growth factor beta (TGF-ß) stimulation were used in this study. Calcitriol was administered for 24 weeks. Renal tubulointerstitial injury and some parameters of mitochondrial function including mitophagy, mitochondrial fission, mitochondrial ROS, mitochondrial membrane potential (MMP), mitochondrial ATP, Complex V activity and mitochondria-associated ER membranes (MAMs) integrity were examined. Additionally, paricalcitol, 3-MA (an autophagy inhibitor), VDR over-expression plasmid, VDR siRNA and Mfn2 siRNA were applied in vitro. RESULTS: The expression of VDR, Pink1, Parkin, Fundc1, LC3II, Atg5, Mfn2, Mfn1 in renal tubular cell of diabetic rats were decreased significantly. Calcitriol treatment reduced the levels of urinary albumin, serum creatinine and attenuated renal tubulointerstitial fibrosis in STZ induced diabetic rats. In addition, VDR agonist relieved mitophagy dysfunction, MAMs integrity, and inhibited mitochondrial fission, mitochondrial ROS. Co-immunoprecipitation analysis demonstrated that VDR interacted directly with Mfn2. Mitochondrial function including mitophagy, mitochondrial membrane potential (MMP), mitochondrial Ca2+, mitochondrial ATP and Complex V activity were decreased dramatically in HK-2 cells under HG/TGF-ß ambience. In vitro pretreatment of HK-2 cells with autophagy inhibitor 3-MA, VDR siRNA or Mfn2 siRNA negated the activating effects of paricalcitol on mitochondrial function. Pricalcitol and VDR over-expression plasmid activated Mfn2 and then partially restored the MAMs integrity. Additionally, VDR restored mitophagy was partially associated with MAMs integrity through Fundc1. CONCLUSION: Activated VDR could contribute to restore mitophagy through Mfn2-MAMs-Fundc1 pathway in renal tubular cell. VDR could recover mitochondrial ATP, complex V activity and MAMs integrity, inhibit mitochondrial fission and mitochondrial ROS. It indicating that VDR agonists ameliorate renal tubulointerstitial fibrosis in diabetic rats partially via regulation of mitochondrial function.

Mitofusin2 Ameliorated Endoplasmic Reticulum Stress and Mitochondrial Reactive Oxygen Species Through Maintaining Mitochondria-Associated Endoplasmic Reticulum Membrane Integrity in Cisplatin-Induced Acute Kidney Injury.

Aims: This study investigated the regulatory effect of Mitofusin2 (Mfn2) on mitochondria-associated endoplasmic reticulum membrane (MAM) integrity and cellular injury in cisplatin-induced acute kidney injury (CP-AKI). Results: CP-AKI mice exhibited decreased expression of Mfn2, increased expression of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), abnormal mitochondrial morphology, and reduced MAMs integrity, accompanied by the activation of mitochondrial reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress (inositol-requiring enzyme 1 [IRE1] and PERK pathways). In in vitro studies, CP-induced mitochondrial ROS, ER-stress activation, and increased apoptosis were accompanied by the downregulation of Mfn2 and MAMs integrity reduction in Boston University mouse proximal tubular cells (BUMPT) and human proximal tubular epithelial cells (HK-2). Pretreatment of BUMPT cells with the Mfn2 plasmid partially restored the integrity of MAMs, negatively controlled IRE1 and PERK pathways, and inhibited cell apoptosis. In contrast, ER-stress and MAMs integrity violations were increased after Mfn2 small-interfering RNA (siRNA) treatment in HK-2 cells under CP treatment. Coimmunoprecipitation analysis demonstrated that Mfn2 interacted with PERK and IRE1. Furthermore, the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), acadesine (AICAR), had a similar effect to Mfn2 plasmid in the regulation of ER stress and MAMs. Conversely, the ER-stress inhibitor, 4-phenylbutyric acid (4-PBA), had no effect on the expression of Mfn2 and MAMs integrity. Innovation and Conclusion: This is the first study to explore the association between MAMs, ER stress, and Mfn2 in CP-AKI. Downregulation of Mfn2 expression abolished the MAMs integrity, and induced ER stress, mitochondrial ROS, and tubular cell apoptosis. This suggests that the Mfn2-MAMs pathway is a potential therapeutic target in CP-AKI. Antioxid. Redox Signal. 40, 16-39. The Ethical Registration number of animal experiment in this study was CSU-2022-01-0095.

Association of vitamin D metabolites with arteriovenous fistula function in hemodialysis patients: A single center study.

INTRODUCTION: Arteriovenous fistula (AVF) is a primary dialysis vascular access commonly used for maintaining hemodialysis (MHD) patients. Vitamin D (VD) is a fat-soluble steroid hormone that is closely related to vascular endothelial function. This study aimed to investigate the association between VD metabolites and AVF failure in patients undergoing HD. METHODS: This study included 443 HD patients using AVF between January 2010 and January 2020. The AVF operations in these patients were newly created by the same physician. We analyzed the AVF patency rates using the chi-square test. Univariate and multivariate logistic regression analyses were performed to explore risk factors for AVF failure. Survival analysis was performed to explore AVF survival at different serum 25-hydroxyvitamin D (25(OH)D) concentrations. RESULTS: Logistic regression analyses showed that male sex; age; BMI; serum albumin, triglyceride, phosphorus, 25(OH)D, iPTH and hemoglobin levels, history of hypertension, CHD, diabetes, stroke, and antiplatelet drug use; and smoking habits were not risk factors for AVF failure. The failure incidence rates of AVF in subjects in the VD deficiency and non VD deficiency group were not statistically significant (25.0% vs. 30.8%, p = 0.344). The AVF failure incidence rates at 1, 3, and 5 years in the patients with 25(OH)D levels more than 20 ng/mL were 26%, 29%, and 37%, respectively, and the one-year AVF failure incidence rates were 27% in the patients with 25(OH)D levels less than 20 ng/mL. In addition, the Kaplan-Meier analysis suggested that the no significant differences were noted when calculating the cumulative survival rates of AVF between the two groups within 50 months of AVF using. CONCLUSION: Our findings suggest that 25(OH)D deficiency is not associated with AVF failure incidence rates, and that 25(OH)D deficiency has no significant impact on long-term cumulative AVF survival rate.

Iron metabolism and chronic inflammation in IgA nephropathy.

IgA nephropathy (IgAN), an immune-mediated chronic inflammatory kidney disease, is the most common primary glomerular disease in Asia, especially in China and Japan. The pathogenesis of IgAN is complex, and the main cause of IgAN is explained by the 'multiple hit' theory, which states that the deposition of immune complexes in renal mesangial cells induces chronic inflammation that leads to kidney damage. Chronic inflammation is associated with iron metabolism, which also plays an essential role in the pathogenesis, progression, diagnosis and prognosis of IgAN. Overall, this review aimed to explore the application of iron metabolism in IgAN by systematically elaborating the relationship between iron metabolism and chronic inflammation in IgAN to speculate on the possible diagnostic and therapeutic significance of iron metabolism indicators in IgAN.

HRD1 attenuates the high uptake of [18F]FDG in hepatocellular carcinoma PET imaging.

INTRODUCTION: Due to individual deviations in tumor tissue uptake, the role of [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) in hepatocellular carcinoma (HCC) diagnosis is limited. ß-Hydroxy ß-methylglutaryl-CoA reductase degradation 1 (HRD1) plays a key role in clearing misfolded proteins. This study is aimed to investigate the role and mechanism of HRD1 in [18F]FDG uptake for the diagnosis of HCC. METHODS: HRD1 expression level was detected using immunohistochemical (IHC) staining in 9 HCC patients. [18F]FDG PET/CT scans were conducted before treatment. [18F]FDG uptakes in HRD1 overexpressed and knockdown transgenic models were measured by γ-counter and microPET imaging. The GLUT1-HRD1 complex was examined by co-immunoprecipitation and IHC assays. GLUT1 expression in different cell lines, xenograft models and HCC patients was evaluated by Western blot and IHC assays. RESULTS: HRD1 was highly expressed in the HCC tumors of patients with low [18F]FDG uptake, while the HRD1 expression was obviously low in the higher [18F]FDG uptake group. Both in vitro and in vivo studies found that HRD1 significantly inhibited [18F]FDG uptake in HCC Huh7 cell lines and animal models. Furthermore, the co-location and interaction of HRD1 with GLUT1 were detected, and the results also indicate that HRD1 could induce the degradation of GLUT1 in vitro and in vivo. CONCLUSION: HRD1 inhibits the high uptake of [18F]FDG in HCC tumor cells by inducing degradation of GLUT1, which leads to decreased diagnostic efficiency of [18F]FDG PET imaging for HCC. ADVANCES IN KNOWLEDGE: This study suggests that HRD1 inhibits the high uptake of [18F]FDG in HCC tumor by inducing degradation of GLUT1. IMPLICATIONS FOR PATIENT CARE: HCC diagnosis with [18F]FDG PET should be accompanied by determination of HRD1 expression, and patients with high tumor HRD1 expression might be unsuitable for [18F]FDG PET.

Mitochondria targeted peptide SS-31 prevent on cisplatin-induced acute kidney injury via regulating mitochondrial ROS-NLRP3 pathway.

OBJECTIVE: This study aimed to assess the effect and mechanism of SS31 on cisplatin-induced acute kidney injury (CP-AKI) both in vivo and in vitro. METHOD: Male mices and HK-2 cells were treated using cisplatin to establish models of CP-AKI. 32 C57BL/6 mices were randomly divided into four groups (control group, CP group, CP + normal saline group, CP + SS-31 group). Cisplatin was intraperitoneally injected once to the mice (25 mg/kg). SS31 was administrated for 10 days at dosages of 10 mg/kg per day. Kidney histological changes and level of reactive oxygen species(ROS) were detected. In vitro studies, HK-2 cells were incubated with cisplatin (50 u M) or combimed with SS-31(100 u M), the level of mitochondrial ROS, apoptosis rate and the the expression of NLRP3, Caspase-1 and IL-1ß were tested. RESULTS: Renal tubulointerstitial apoptosis and oxidative stress were significantly increased in CP-AKI mice. Cisplatin caused elevation of serum creatinine (Scr), blood urea nitrogen (BUN) levels and enhanced IL-1ß, caspase1 and NLRP3 expression, the electron microscopy examination showed mitochondria cristae swelling, mitochondrial spheres and partial ridge breakdown in renal tubular cell of CP-AKI mice. SS31 treatment could effectively suppress mitochondrial ROS, ameliorate these lesions and decrease the expression of NLRP3, IL-1ß and Caspase1. In vitro studies, SS31 could restored the level of mitochondrial ROS and downregulate apoptosis rate in HK-2 cells, moreover, the elevated expression of NLRP3, IL-1ß and Caspase-1were restored. CONCLUSION: SS31 could protect CP-AKI in mices, which might be due to an anti-oxidative and anti-apoptotic action via regulating mitochondrial ROS-NLRP3 pathway. NLRP3 inflammasome might be considered as a novel therapeutic target of CP-AKI.

Comparison of 99mTc-DTPA and serum creatinine, cystatin C in detection of glomerular filtration rate: a retrospective clinical data analysis of 744 Chinese subjects.

BACKGROUND: To compare the accuracy of various equations for estimating glomerular filtration rate. METHODS: Chronic kidney disease was classified by Tc-DTPA scintigraphy (reference glomerular filtration rate), estimating glomerular filtration rate was estimated using various formulas. The similarity to reference glomerular filtration rate decide the accuracy of estimating glomerular filtration rate. RESULTS: Overall, the Fengscr-cys equation had significantly higher accuracy and correct proportion in chronic kidney disease stage classification than other equations. The subgroup analysis showed that Fengscr-cys equation was slightly more precise than other equations both in the male and female patients. Moreover, in patients older than 60 years or whose reference glomerular filtration rate was above 60 ml/min, Fengscr-cys equation also showed better accuracy. CONCLUSION: Our data suggest that estimating glomerular filtration rate equations evaluated by serum cystatin C were better than serum creatinine-based equations, estimating glomerular filtration rate equations evaluated by both serum creatinine and cystatin C were better than those evaluated by serum creatinine or cystatin C alone. Among all enrolled equations, Fengscr-cys equation might be the best one to evaluate glomerular filtration rate in general Chinese paticipants.

Application of blunt dissection in ESD of a gastric submucosal tumor.

We performed endoscopic submucosal dissection of a gastric fundus tumor. It was difficult to strip the tumor completely due to space limitation, and we used blunt dissection to remove the tumor quickly and safely. Firstly, the basal area of the 2.5 cm submucosal tumor located in the gastric fundus was cut open, and the mucosa was dissected. The tumor was difficult to peel, therefore, a snare was used and the tumor was pulled and tightened slightly. Short electronic coagulation was used during the procedure. The tumor was then bluntly dissected. This method ensured rapid and complete removal of the tumor.

A parallel study of careHPV and Hybrid Capture 2 human papillomavirus DNA testing for cervical cancer screening in rural China.

Hybrid Capture 2 (HC2) has been demonstrated to be a feasible screening method for cervical cancer. Based upon HC2 technology, careHPV is a simple, rapid, accurate, and inexpensive screening test for women in low-resource settings. This study aims to characterize both the careHPV test and HC2 test, and to compare careHPV results of specimens stored in careHPV test collection medium (TCM) to HC2 results from partner specimens stored in Qiagen specimen transport medium and TCM. The positive rates of high-risk HPV in careHPV, HC2, and HC2 (TCM) were 13.2% (108/818), 13.2% (108/818), and 13.6% (111/818), respectively. The agreement rates of pairwise tests were 95.8% (95% CI: 94.5-97.2%), 96.7% (95% CI: 95.5-97.9%), and 97.2% (95% CI: 96.1-98.3%), respectively. The Kappa values of the pairwise tests were 0.82 (95% CI: 0.76-0.88), 0.86 (95% CI: 0.81-0.91), and 0.88 (95% CI: 0.83-0.93), respectively. Based on these findings, although careHPV is demonstrated to be a viable alternative to the HC2 test, improvements on the careHPV test are still required prior to its implementation as a suitable screening method for women in low-resource settings. Further studies on the significance and applicability of the careHPV test must be performed.

Over-expression of mitochondrial antiviral signaling protein inhibits coxsackievirus B3 infection by enhancing type-I interferons production.

BACKGROUND: Recent studies have revealed that Mitochondrial Antiviral Signaling (MAVS) protein plays an essential role in the inhibition of viral infection through type I interferon (IFN) pathway. It has been shown that 3C (pro) cysteine protease of coxsackievirus B3 (CVB3) cleaves MAVS to inhibit type I IFNs induction. Other workers also found that MAVS knock-out mice suffered CVB3 susceptibility and severe histopathological change. Accordingly,our experiments were designed to explore the protection of over-expressing MAVS against CVB3 infection and the possible mechanism. RESULTS: In this study, HeLa cells (transfected with MAVS constructs pre- or post- exposure to CVB3) were used to analyze the function of exogenous MAVS on CVB3 infection. The results revealed that though CVB3 infection induced production of type I IFNs, viral replication and cell death were not effectively inhibited. Similarly, exogenous MAVS increased type I IFNs moderately. Morever, we observed robust production of type I IFNs in CVB3 post-infected HeLa cells thereby successfully inhibiting CVB3 infection, as well formation of cytopathic effect (CPE) and cell death. Finally, introduction of exogenous MAVS into CVB3 pre-infected cells also restricted viral infection efficiently by greatly up-regulating IFNs. CONCLUSIONS: In summary, exogenous MAVS effectively prevents and controls CVB3 infection by modulating and promoting the production of type I IFNs. The IFNs level in MAVS over-expressing cells is still tightly regulated by CVB3 infection. Thus, the factors that up-regulate MAVS might be an alternative prescription in CVB3-related syndromes by enhancing IFNs production.

[Committed differentiation of transplanted bone derived mesenchymal stem cells and their potential to amend damaged liver functions: in vivo experiment with mice].

OBJECTIVE: To observe whether bone mesenchymal stem cells (MSCs) have the potential to transdifferentiate into functional hepatocyte-like cells in the special "niche" as well as the therapeutic feasibility to repair damaged liver in mice. METHODS: 20 nude mice were randomly divided into four groups (n = 5 in each group): Group A: 1.0 ml/kg of carbon tetrachloride (CCl(4)) (dissolved in olive oil by ratio of 1:1) was injected into the peritoneum of mice twice a week for 5 weeks. GFP-positive MSCs (1 x 10(6) cells) were injected into the caudal tail vein 1 week after the first dose of CCl(4); Group B: treated with CCl(4) as in A, but received the same volume of saline; Group C: normal nude mice with GFP-positive MSCs Transplanted in the same way as in A. Group D: normal controls. 4 weeks after the cell transplantation, all animal subjects were killed. Liver function tests (LFT), histology of HE and Masson staining as well as double immunofluorescent staining for GFP and albumin were studied in all groups. RESULTS: The hepatic fibrosis in group A & B confirmed the success of model for liver damage and there was no marked difference in the percent of the area occupied by collagen between two groups (10.5 +/- 1.5 vs 12.7 +/- 1.6, t = -2.238, P > 0.05). GFP-positive MSCs were mainly observed around portal area or interspace of lobules in group A. Some of GFP-positive cells also express albumin (35% +/- 7%). While in group B, C or D, there is no such findings. The level of serum albumin in group A was higher than that in group B (24.4 g/L +/- 3.3 g/L vs 18.6 g/L +/- 2.9 g/L, P < 0.05) while the level of ALT was also different between two groups (121 U/L +/- 21 U/L vs 192 U/L +/- 29 U/L, P < 0.05). CONCLUSION: The stimulus of persistent liver damage might enhances the migration of MSCs to the liver, in which some of the MSCs have the potential to transdifferentiate into hepatocyte-like cells. Transplantation of MSCs might amend the damaged tissue of host liver to a certain extent.