YME1L-mediated mitophagy protects renal tubular cells against cellular senescence under diabetic conditions.

BACKGROUND: The senescence of renal tubular epithelial cells (RTECs) is crucial in the progression of diabetic kidney disease (DKD). Accumulating evidence suggests a close association between insufficient mitophagy and RTEC senescence. Yeast mitochondrial escape 1-like 1 (YME1L), an inner mitochondrial membrane metalloprotease, maintains mitochondrial integrity. Its functions in DKD remain unclear. Here, we investigated whether YME1L can prevent the progression of DKD by regulating mitophagy and cellular senescence. METHODS: We analyzed YME1L expression in renal tubules of DKD patients and mice, explored transcriptomic changes associated with YME1L overexpression in RTECs, and assessed its impact on RTEC senescence and renal dysfunction using an HFD/STZ-induced DKD mouse model. Tubule-specific overexpression of YME1L was achieved through the use of recombinant adeno-associated virus 2/9 (rAAV 2/9). We conducted both in vivo and in vitro experiments to evaluate the effects of YME1L overexpression on mitophagy and mitochondrial function. Furthermore, we performed LC-MS/MS analysis to identify potential protein interactions involving YME1L and elucidate the underlying mechanisms. RESULTS: Our findings revealed a significant decrease in YME1L expression in the renal tubules of DKD patients and mice. However, tubule-specific overexpression of YME1L significantly alleviated RTEC senescence and renal dysfunction in the HFD/STZ-induced DKD mouse model. Moreover, YME1L overexpression exhibited positive effects on enhancing mitophagy and improving mitochondrial function both in vivo and in vitro. Mechanistically, our LC-MS/MS analysis uncovered a crucial mitophagy receptor, BCL2-like 13 (BCL2L13), as an interacting partner of YME1L. Furthermore, YME1L was found to promote the phosphorylation of BCL2L13, highlighting its role in regulating mitophagy. CONCLUSIONS: This study provides compelling evidence that YME1L plays a critical role in protecting RTECs from cellular senescence and impeding the progression of DKD. Overexpression of YME1L demonstrated significant therapeutic potential by ameliorating both RTEC senescence and renal dysfunction in the DKD mice. Moreover, our findings indicate that YME1L enhances mitophagy and improves mitochondrial function, potentially through its interaction with BCL2L13 and subsequent phosphorylation. These novel insights into the protective mechanisms of YME1L offer a promising strategy for developing therapies targeting DKD.

Association between the duration of diabetes and gram-negative bacterial infection in diabetic foot infections: a case-control study.

This retrospective case-control study was designed to explore the association between the duration of diabetes and gram-negative bacterial infection in diabetic foot infections (DFIs). All DFI patients hospitalized in the Department of Endocrinology in the Sixth Affiliated Hospital of Sun Yat-sen University between 2013 and 2019 with positive microbial culture results were included. Cases were defined as DFI patients whose microbial cultures grew gram-negative bacteria (including polymicrobial flora). Controls were defined as DFI patients whose positive microbial cultures did not grow gram-negative bacteria. Clinical data were extracted from the hospital information system. Stabilized inverse probability weighting was used to balance between-group differences at baseline. Confounders were selected using a directed acyclic graph. Missing data were imputed with the multiple imputation of chained equations method. Odds ratios (ORs) with 95% confidence intervals (CIs) and Ptrend for associations between the duration of diabetes and gram-negative bacterial infection were obtained using binomial logistic regression models. The weighted OR of gram-negative bacterial infection for DFI patients with a moderate duration of diabetes (8~19 years) compared with those with a short duration (0~7 years) was 3.87 (95% CI: 1.15 to 13.07), and the OR for those with a longer duration (20~30 + years) was 7.70 (95% CI: 1.45 to 41.00), and there was a dose-response trend with increasing duration of diabetes (weighted Ptrend = 0.007). The results demonstrated that a long duration of diabetes might be associated with an increased risk of gram-negative bacterial infection in type 2 diabetes patients with DFI.

Neuroprotective effects of an Nrf2 agonist on high glucose-induced damage in HT22 cells.

BACKGROUND: Oxidative stress is the hallmark of diabetic encephalopathy, which may be caused by hyperglycaemic toxicity. We aimed to discover pharmacologic targets to restore redox homeostasis. We identified the transcription factor Nrf2 as such a target. METHODS: HT22 cells were cultured in 25 or 50 mM D-glucose with various concentrations of sulforaphane (SFN) (from 1.25 to 5.0 µM). Cell viability was tested with the Cell Counting Kit-8 assay. Reactive oxygen species (ROS) production was detected with an inverted fluorescence microscope using the dichlorodihydrofluorescein-diacetate fluorescent probe. The expression of NF-E2-related factor 2 (Nrf2), haem oxygenase-1 (HO-1) and nuclear factor-κB (NF-κB) at the mRNA and protein levels was detected by reverse transcription quantitative polymerase chain reaction and western blotting. RESULT: We found that a high glucose concentration (50 mM) increased the generation of ROS, downregulated the expression of Nrf2/HO-1 and upregulated the expression of NF-κB. Moreover, HT22 cell viability significantly decreased after culture in high-glucose medium for 24, 48 and 72 h, whereas the activation of the Nrf2/HO-1 pathway using a pharmacological Nrf2 activator abrogated this high-glucose-induced toxicity. CONCLUSION: This study suggests that the activation of the Nrf2-ARE signalling pathway might be a therapeutic target for the treatment of diabetic encephalopathy.

Plasma microRNA-586 is a new biomarker for acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) is one of the major causes of morbidity and mortality in patients receiving allogeneic hematopoietic cell transplantation (allo-HSCT). MicroRNAs (miRs) were found to have the potential to be the new biomarkers of aGVHD. In this study, we collected samples from 98 patients who underwent allo-HSCT; 63 patients developed aGVHD, and 35 patients did not. Plasma samples were collected at three time points (before aGVHD, at the onset of aGVHD, and after aGVHD) from 52 patients, and the miR-586 expression level was detected by quantitative real-time PCR. We found that the plasma miR-586 level was decreased at the onset of grade I-II aGVHD (P = 0.074). In contrast, when infections were detected, plasma miR-586 level was increased. Moreover, we detected the miR-586 expression level in patients who had infections but did not have aGVHD, and we found that miR-586 was upregulated (P = 0.005). We also compared the plasma miR-586 level at day 7 after transplantation between aGVHD patients and control patients. In the aGVHD group, there was a considerably higher miR-586 expression in comparison with the non-aGVHD group (P < 0.05). A more significant difference between the two groups was found when the patients with infections were excluded (P = 0.004). Furthermore, receive operating characteristic (ROC) analysis indicated that a higher expression level of miR-586 at day 7 could predict impending aGVHD. The optimal cutoff value of miR-586 to predict aGVHD was 2200 copies/µL with a sensitivity of 87.5 % and specificity of 55.0 %, and the area under the curve (AUC) was 0.739 (95 % CI 0.598-0.880, P = 0.004). Our study suggests that miR-586 might participate in the occurrence of aGVHD and could be a putative target for novel aGVHD therapy. The plasma level of miR-586 at day 7 after allo-HSCT would be a potential biomarker for predicting the occurrence of aGVHD.

A GC-MS-based untargeted metabolomics approach for comprehensive metabolic profiling of mycophenolate mofetil-induced toxicity in mice.

Background: Mycophenolate mofetil (MMF), the morpholinoethyl ester of mycophenolic acid, is widely used for maintenance immunosuppression in transplantation. The gastrointestinal toxicity of MMF has been widely uncovered. However, the comprehensive metabolic analysis of MMF-induced toxicity is lacking. This study is aimed to ascertain the metabolic changes after MMF administration in mice. Methods: A total of 700 mg MMF was dissolved in 7 mL dimethyl sulfoxide (DMSO), and then 0.5 mL of mixture was diluted with 4.5 mL of saline (100 mg/kg). Mice in the treatment group (n = 9) were given MMF (0.1 mL/10 g) each day via intraperitoneal injection lasting for 2 weeks, while those in the control group (n = 9) received the same amount of blank solvent (DMSO: saline = 1:9). Gas chromatography-mass spectrometry was utilized to identify the metabolic profiling in serum samples and multiple organ tissues of mice. The potential metabolites were identified using orthogonal partial least squares discrimination analysis. Meanwhile, we used the MetaboAnalyst 5.0 (http://www.metaboanalyst.ca) and Kyoto Encyclopedia of Genes and Genomes database (http://www.kegg.jp) to depict the metabolic pathways. The percentages of lymphocytes in spleens were assessed by multiparameter flow cytometry analysis. Results: Compared to the control group, we observed that MMF treatment induced differential expression of metabolites in the intestine, hippocampus, lung, liver, kidney, heart, serum, and cortex tissues. Subsequently, we demonstrated that multiple amino acids metabolism and fatty acids biosynthesis were disrupted following MMF treatment. Additionally, MMF challenge dramatically increased CD4+ T cell percentages but had no significant influences on other types of lymphocytes. Conclusion: MMF can affect the metabolism in various organs and serum in mice. These data may provide preliminary judgement for MMF-induced toxicity and understand the metabolic mechanism of MMF more comprehensively.

The possible mechanisms underlying the impairment of HIF-1α pathway signaling in hyperglycemia and the beneficial effects of certain therapies.

Hypoxia-inducible factor 1 alpha (HIF-1α), an essential transcription factor which mediates the adaptation of cells to low oxygen tensions, is regulated precisely by hypoxia and hyperglycemia, which are major determinants of the chronic complications associated with diabetes. The process of HIF-1α stabilization by hypoxia is clear; however, the mechanisms underlying the potential deleterious effect of hyperglycemia on HIF-1α are still controversial, despite reports of a variety of studies demonstrating the existence of this phenomenon. In fact, HIF-1α and glucose can sometimes influence each other: HIF-1α induces the expression of glycolytic enzymes and glucose metabolism affects HIF-1α accumulation in some cells. Although hyperglycemia upregulates HIF-1α signaling in some specific cell types, we emphasize the inhibition of HIF-1α by high glucose in this review. With regard to the mechanisms of HIF-1α impairment, the role of methylglyoxal in impairment of HIF-1α stabilization and transactivation ability and the negative effect of reactive oxygen species (ROS) on HIF-1α are discussed. Other explanations for the inhibition of HIF-1α by high glucose exist: the increased sensitivity of HIF-1α to Von Hippel-Lindau (VHL) machinery, the role of osmolarity and proteasome activity, and the participation of several molecules. This review aims to summarize several important developments regarding these mechanisms and to discuss potentially effective therapeutic techniques (antioxidants eicosapentaenoic acid (EPA) and metallothioneins (MTs), pharmaceuticals cobalt chloride (CoCl2), dimethyloxalylglycine (DMOG), desferrioxamine (DFO) and gene transfer of constitutively active forms of HIF-1α) and their mechanisms of action for intervention in the chronic complications in diabetes.

Identification and analysis of cellular senescence-associated signatures in diabetic kidney disease by integrated bioinformatics analysis and machine learning.

Background: Diabetic kidney disease (DKD) is a common complication of diabetes that is clinically characterized by progressive albuminuria due to glomerular destruction. The etiology of DKD is multifactorial, and numerous studies have demonstrated that cellular senescence plays a significant role in its pathogenesis, but the specific mechanism requires further investigation. Methods: This study utilized 5 datasets comprising 144 renal samples from the Gene Expression Omnibus (GEO) database. We obtained cellular senescence-related pathways from the Molecular Signatures Database and evaluated the activity of senescence pathways in DKD patients using the Gene Set Enrichment Analysis (GSEA) algorithm. Furthermore, we identified module genes related to cellular senescence pathways through Weighted Gene Co-Expression Network Analysis (WGCNA) algorithm and used machine learning algorithms to screen for hub genes related to senescence. Subsequently, we constructed a cellular senescence-related signature (SRS) risk score based on hub genes using the Least Absolute Shrinkage and Selection Operator (LASSO), and verified mRNA levels of hub genes by RT-PCR in vivo. Finally, we validated the relationship between the SRS risk score and kidney function, as well as their association with mitochondrial function and immune infiltration. Results: The activity of cellular senescence-related pathways was found to be elevated among DKD patients. Based on 5 hub genes (LIMA1, ZFP36, FOS, IGFBP6, CKB), a cellular senescence-related signature (SRS) was constructed and validated as a risk factor for renal function decline in DKD patients. Notably, patients with high SRS risk scores exhibited extensive inhibition of mitochondrial pathways and upregulation of immune cell infiltration. Conclusion: Collectively, our findings demonstrated that cellular senescence is involved in the process of DKD, providing a novel strategy for treating DKD.

TRAP1 inhibits MARCH5-mediated MIC60 degradation to alleviate mitochondrial dysfunction and apoptosis of cardiomyocytes under diabetic conditions.

Mitochondrial dysfunction and cell death play important roles in diabetic cardiomyopathy, but the underlying mechanisms remain unclear. Here, we report that mitochondrial dysfunction and cell apoptosis are prominent features of primary cardiomyocytes after exposure to high glucose/palmitate conditions. The protein level of MIC60, a core component of mitochondrial cristae, is decreased via ubiquitination and degradation under these conditions. Exogenous expression of MIC60 alleviates cristae disruption, mitochondrial dysfunction and apoptosis. Moreover, we identified MARCH5 as an E3 ubiquitin ligase that specifically targets MIC60 in this process. Indeed, MARCH5 mediates K48-linked ubiquitination of MIC60 at Lys285 to promote its degradation. Mutation of the ubiquitination site in MIC60 or the MIC60-interacting motifs in MARCH5 abrogates MARCH5-mediated MIC60 ubiquitination and degradation. Silencing MARCH5 significantly alleviates high glucose/palmitate-induced mitochondrial dysfunction and apoptosis in primary cardiomyocytes. In addition to E3 ubiquitin ligases, molecular chaperones also play important roles in protein stability. We previously reported that the mitochondrial chaperone TRAP1 inhibits the ubiquitination of MIC60, but the detailed mechanism is unknown. Here, we find that TRAP1 performs this function by competing with MARCH5 for binding to MIC60. Our findings provide new insights into the mechanism underlying mitochondrial dysfunction in cardiomyocytes in diabetic cardiomyopathy. MARCH5 promotes ubiquitination of MIC60 to induce MIC60 degradation, mitochondrial dysfunction and apoptosis in cardiomyocytes under diabetic conditions. TRAP1 inhibits MARCH5-mediated ubiquitination by competitively interacting with MIC60.

A Randomized Clinical Trial of Intravenous Methylprednisolone With 2 Protocols in Patients With Graves Orbitopathy.

CONTEXT: Intravenous glucocorticoid (IVGC) is an accessible and affordable treatment for Graves orbitopathy (GO); the 4.5-g protocol is well studied, but many details of treatment protocols need to be clarified. OBJECTIVE: To compare the efficacy and safety of weekly and monthly protocol of IVGC in GO. METHODS: A prospective, randomized, observer-masked, single-center clinical trial, followed up to week 24, at the third affiliated hospital of Southern Medical University; 58 patients with active and moderate to severe GO, aged 18-60 years old, who had not received relevant treatment were included. The intervention was weekly protocol or monthly protocol of IVGC; both received a cumulative dose of methylprednisolone 4.5 g and had a duration of 12 weeks. The overall effective rate, improvement of quality of life (QOL) and signal intensity ratio (SIR) were measured. RESULTS: There was no significant difference in the effective rate between the 2 groups at week 12 and week 24 (86.21% vs 72.41%, P = .195; 86.21% vs 82.61%, P = .441), there was no significant difference in the improvement of clinical activity score, exophthalmos, soft tissue involvement, diplopia, and QOL. At week 24, the mean SIR and maximum SIR of the 2 groups were lower than those before treatment, and there were no statistically significant difference between the 2 groups. There was no significant difference in the incidence of adverse events between the 2 groups (31.03% vs 27.59%, P = .773). CONCLUSION: The efficacy and safety of the 2 protocols are comparable; the monthly protocol could be used as an alternative to the weekly protocol.

Cardioprotective effect of sodium ferulate in diabetic rats.

Reactive oxygen species (ROS) play important roles in the occurrence and development in diabetic cardiomyopathy (DC). Ferulic acid is one of the ubiquitous compounds in diet. Sodium ferulate (SF) is its sodium salt. SF has potent free radical scavenging activity and can effectively scavenge ROS. The study investigated the effect of SF on cardioprotection in diabetic rats. The diabetic rats induced by streptozotocin (STZ) were treated with SF (110mg/kg) by gavage per day for 12 weeks. Results showed that the levels of nitric oxide (NO) and superoxide dismutase (SOD) activity in plasma and myocardium in SF-treated group were significantly higher than those in diabetic control group. The levels of malondialdehyde (MDA) in plasma and myocardium in SF-treated group were significantly lower than those in diabetic control group. Expression of connective tissue growth factor (CTGF) in myocardium in SF-treated group was apparently lower than that in diabetic control group. Compared with normal control group, electron micrographs of myocardium in diabetic control group showed apparently abnormality, while that was significantly ameliorated in SF-treated group. The study demonstrated that SF has a cardioprotective effect via increasing SOD activity and NO levels in plasma and myocardium, inhibiting oxidative stress in plasma and myocardium, and inhibiting the expression of CTGF in myocardium in diabetes rats.

Genetic effects of adiponectin on blood lipids and blood pressure.

OBJECTIVE: Results from the published studies on the association of adiponectin gene (ADIPOQ) polymorphisms with blood lipids and blood pressure are conflicting. We investigated the association of three ADIPOQ polymorphisms, +45 T > G (rs2241766), +276 G > T (rs1501299) and -11377 C > G (rs266729), with these traits in this meta-analysis. RESEARCH DESIGN AND METHODS: We included 35 studies in this meta-analysis. Dominant models were used for this meta-analysis. RESULTS: We did not detect a significant association of the -11377 C > G polymorphism with blood lipids or blood pressure (P > 0·05). The association of the +45 T > G polymorphism with blood lipids and blood pressure was, similarly, not significant (P > 0·05). The meta-analysis suggested a significant overall association of the +276 G > T polymorphism with lower levels of total cholesterol: weighted mean difference (WMD) = -0·10, 95% confidence interval (CI, -0·17, -0·03), P = 0·005, P(heterogeneity) = 0·04. This association was marginally significant in East Asians and East Asians with type 2 diabetes: WMD = -0·10, 95% CI (-0·20, 0·00), P = 0·05, P(heterogeneity) = 0·002, and WMD = -0·09, 95% CI (-0·18, -0·00), P = 0·05, P(heterogeneity) = 0·80, respectively. After exclusion of a study that was the source of heterogeneity, the association was significant in overall populations and marginally significant in East Asians: WMD= -0·06, 95% CI (-0·11, -0·01), P = 0·01, P(heterogeneity) = 0·98, and WMD = -0·06, 95% CI (-0·12, 0·00), P = 0·07, P(heterogeneity) = 0·83, respectively. However, none of these associations were significant after Bonferroni correction (significant threshold: P < 0·003). CONCLUSIONS: Our meta-analysis does not suggest any association of the three ADIPOQ polymorphisms with blood lipids and blood pressure.

Expression of human globular adiponectin-glucagon-like peptide-1 analog fusion protein and its assay of glucose-lowering effect in vivo.

In this study, human globular adiponectin-glucagon-like peptide-1 analog (gAd-GLP-1-A) fusion protein was expressed and its glucose-lowering effect was measured in vivo. We constructed a prokaryotic expression vector PET28a-gAd-GLP-1-A and transformed the vector into Escherichia coli BL21 (DE3). A recombinant fusion protein of about 25KD was expressed from BL21 (DE3) cells after isopropylthio-ß-D-galactoside induction. This protein was N-terminal His-tagged gAd-GLP-1-A fusion protein. Most of the protein was expressed in inclusion body. The fusion protein in inclusion body was purified by using High-Affinity Nickel Iminodiacetic Acid Resin and refolded in urea gradient refolding buffer. The refolded protein was incubated with enterokinase to remove the N-terminal His-tag. The fusion protein without His-tag is gAd-GLP-1-A fusion protein, which exhibited significant glucose-lowering effect in diabetic mice.

TRAP1 inhibits MIC60 ubiquitination to mitigate the injury of cardiomyocytes and protect mitochondria in extracellular acidosis.

Extracellular acidosis-induced mitochondrial damage of cardiomyocytes leads to cardiac dysfunction, but no detailed mechanism or efficient therapeutic target has been reported. Here we found that the protein levels of MIC60 were decreased in H9C2 cells and heart tissues in extracellular acidosis, which caused mitochondrial damage and cardiac dysfunction. Overexpression of MIC60 maintains H9C2 cells viability, increases ATP production and mitochondrial membrane potential, mitigates the disruptions of mitochondrial structure and cardiac injury. Mechanistically, extracellular acidosis excessively promoted MIC60 ubiquitin-dependent degradation. TRAP1 mitigated acidosis-induced mitochondrial impairments and cardiac injury by directly interacting with MIC60 to decrease its ubiquitin-dependent degradation in extracellular acidosis.

Association of the apolipoprotein A5 gene -1131 T>C polymorphism with fasting blood lipids: a meta-analysis in 37859 subjects.

BACKGROUND: Studies examining the association of apolipoprotein A5 (APOA5) gene -1131 T>C polymorphism with blood lipids produced inconsistent results. In this meta-analysis encompassing all the relevant studies, we aimed to investigate the association of the -1131 T>C polymorphism with fasting blood lipids. METHODS: We limited our analysis to the following four blood lipid variables: total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Subjects were confined to adults who were at least 18 years old. A dominant model was used for this meta-analysis. 37 studies with 37859 subjects were included in this meta-analysis. RESULTS: The results showed that the carriers of -1131C allele have higher blood TC and TG than the non-carriers: standardized mean difference (SMD) = 0.08, 95% confidence interval (CI, 0.05, 0.11), P < 0.00001, P(heterogeneity) = 0.42, and SMD = 0.31, 95% CI (0.27, 0.34), P < 0.00001, P(heterogeneity) = 0.0003, respectively. Significant association between the -1131 T>C polymorphism and lower blood HDL-C was also detected under the dominant model: SMD = -0.17, 95% CI (-0.21, -0.14), P < 0.00001, P(heterogeneity) = 0.003. CONCLUSIONS: Our meta-analysis supports the strong association of the APOA5 -1131 T>C polymorphism with higher levels of TC and TG, and lower levels of HDL-C.

Association of the fatty acid-binding protein 2 gene Ala54Thr polymorphism with insulin resistance and blood glucose: a meta-analysis in 13451 subjects.

BACKGROUND: The results from the published studies on the association of fatty acid-binding protein 2 (FABP2) Ala54Thr polymorphism with insulin resistance and blood glucose are conflicting. In this meta-analysis, we investigated the association of the FABP2 Ala54Thr polymorphism with insulin resistance and blood glucose. METHODS: We collected data on fasting blood glucose and fasting insulin, 2-h blood glucose (2-h BG) and 2-h insulin (2-h insulin), and homeostasis model assessment insulin resistance index. A dominant model was used for this meta-analysis. RESULTS: Thirty-one studies with 13 451 subjects were included in this meta-analysis. The carriers of Thr54 allele have significantly higher homeostasis model assessment insulin resistance index and marginally higher fasting insulin than the non-carriers: standardized mean difference (SMD) = 0.07, 95% confidence interval (CI, 0.02, 0.12), p = 0.007, p(heterogeneity) = 0.19 and SMD = 0.08, 95% CI (-0.01, 0.17), p = 0.07, p(heterogeneity) < 0.00001, respectively. A borderline significant association between the FABP2 Ala54Thr polymorphism and an increased 2-h BG was also detected under the dominant model: SMD = 0.10, 95% CI (0.00, 0.20), p = 0.05, p(heterogeneity) = 0.09. In addition, a borderline association between this polymorphism and an increased fasting blood glucose in populations of other ethnic origins was detected under the dominant model: SMD = 0.11, 95% CI (-0.00, 0.23), p = 0.06, p(heterogeneity) = 0.03. CONCLUSIONS: Our meta-analysis suggests that the Thr54 allele of the FABP2 Ala54Thr is weakly associated with a higher degree of insulin resistance, higher level of fasting insulin and higher level of 2-h BG. Our meta-analysis also suggests a weak association between this polymorphism and an increased fasting blood glucose in populations of other ethnic origins under the dominant model.

Tumor Necrosis Factor Receptor-Associated Protein 1 Protects against Mitochondrial Injury by Preventing High Glucose-Induced mPTP Opening in Diabetes.

Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease worldwide. Renal tubular epithelial cell apoptosis and tubular atrophy have been recognized as indicators of the severity and progression of DKD, while the mechanism remains elusive. Tumor necrosis factor receptor-associated protein 1 (TRAP1) plays critical roles in apoptosis. The aim of this study was to investigate the protective role TRAP1 plays in DKD and to study the potential underlying mechanisms. TRAP1 expression was decreased, and mitochondria were injured in NRK-52e cells under high-glucose (HG) conditions. The overexpression of TRAP1 ameliorated HG-induced apoptosis, increased cell viability, maintained mitochondrial morphology, adenosine triphosphate (ATP) levels, and mitochondrial membrane potential (MMP), and buffered oxidative stress, whereas TRAP1 knockdown aggravated these effects. The protective effects of TRAP1 may be exerted via the inhibition of mitochondrial permeability transition pore (mPTP) opening, and the damage caused by TRAP1 knockdown can be partially reversed by treatment with the mPTP opening inhibitor cyclosporin A (CsA). In vivo, TRAP1 expression upregulation by AAV2/9 injection prevented renal dysfunction, ameliorated histopathological changes, maintained mitochondrial morphology and function, and reduced apoptosis and reactive oxygen species (ROS) in STZ-treated DKD rats. Thus, our results suggest that TRAP1 ameliorates diabetes-induced renal injury by preventing abnormal mPTP opening and maintaining mitochondrial structure and function, which may be treated as a potential target for DKD treatment.

TRAP1 attenuates H9C2 myocardial cell injury induced by extracellular acidification via the inhibition of MPTP opening.

Extracellular acidification leads to cardiac dysfunction in numerous diseases. Mitochondrial dysfunction plays an important role in this process. However, the mechanisms through which extracellular acidification induces mitochondrial dysfunction remain unclear. Tumor necrosis factor receptor­associated protein 1 (TRAP1) maintains mitochondrial function and cell viability in tumor and non­tumor cells. In the present study, extracellular acidification was found to induce H9C2 cell apoptosis, mitochondrial dysfunction and TRAP1 expression. The overexpression of TRAP1 attenuated H9C2 cell injury, while the silencing of TRAP1 exacerbated it. Moreover, mitochondrial permeability transition pore (MPTP) opening, which is associated with the mitochondrial apoptotic pathway and cell death, was also increased in acidic medium. The overexpression of TRAP1 inhibited MPTP opening, while the silencing of TRAP1 promoted it. The protective effect of TRAP1 on cardiomyocytes was abolished by the addition of a specific MPTP opening promoter. Similarly, a specific MPTP opening inhibitor reversed cell injury by silencing TRAP1. Taken together, the findings of the present study demonstrate that TRAP1 attenuates H9C2 cell injury induced by extracellular acidification by inhibiting MPTP opening.

[Sodium ferulate treatment and interventional mechanism reverse erectile dysfunction in streptozotocin-induced diabetic rats].

OBJECTIVE: To investigate the effect and mechanism of sodium ferulate (SF) on reversing erectile dysfunction in diabetes mellitus (DM) rats. METHODS: Forty-four male adult Sprague-Dawley rats were induced for diabetes by an intraperitoneal injection of streptozotocin. Then the successful models were randomly divided into DM + SF group and DM group (22 rats each respectively). The rats in DM +SF group were treated with sodium ferulate (100 mg x kg(-1) x d(-1)) through a daily gastric lavage. At Week 12, the erectile function of all rats was evaluated and serum samples were harvested. The SOD, CAT, NOS, MDA and NO levels in corpus cavernosum and serum were all measured. The pathologic change in penile cavernous body was observed microscopically. RESULTS: The diabetic rat models were successfully established. The erectile function was much better in normal control group and DM + SF group than that in DM group. And the penile erection rates in three groups were 100%, 66% and 22% respectively. The activity levels of SOD, CAT and NOS were markedly decreased in DM group as compared to those in normal control group and DM + SF group (P < 0.01). The NO content was approximately equal in normal control group and DM + SF group (112 +/- 28) nmol/ml vs (137 +/- 25) nmol/ml. But both were much higher than that in DM group (56 +/- 10) nmol/ml, both P < 0.01. The MDA content was markedly increased in DM group as compared to those in normal control group and DM + SF group (both P < 0.01). Microscopically, muscle fibers in penile cavernous body arranged disorderly, muscular mantle damaged and desmoplasia scattered among muscle fibers in DM group. CONCLUSION: Sodium ferulate may play interventional roles in reversing diabetic erectile dysfunction through metabolic regulation of free radicals, antagonism of oxidative insults and enhancement of NO production.

Sodium ferulate attenuates high-glucose-induced oxidative injury in HT22 hippocampal cells.

The aim of the present study was to investigate the protective effects of sodium ferulate (SF) on HT22 hippocampal cells under a high glucose concentration. Cells were cultured in normal glucose (25 mM D-glucose) or high glucose (50 mM D-glucose) with various concentrations of SF (50, 100, 250 or 500 µM) for 0, 48 and 72 h. Cell viability was tested using a Cell Counting Kit-8 assay. Reactive oxygen species (ROS) production was detected using flow cytometry. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nuclear factor-κB (NF-κB) at the mRNA and protein levels were detected using a reverse transcription-quantitative polymerase chain reaction analysis and western blotting. HT22 hippocampal cell viability was revealed to be substantially decreased following culturing in high glucose medium (50 mM) for 48 and 72 h. The addition of 100 µM SF abrogated this high-glucose-induced toxicity, but higher concentrations of SF (250 and 500 µM) were harmful to the cells. Furthermore, a high glucose concentration increased the generation of ROS, downregulated the expression of Nrf2/HO-1 and upregulated the expression of NF-κB subsequent to culturing for 72 h, whereas the addition of the appropriate concentration of SF attenuated these effects. To the best of our knowledge, the present study is the first to report such results and provide evidence that SF protects HT22 cells from high glucose-induced toxicity by activating the Nrf2/HO-1 pathway and inhibiting the expression of NF-κB, which may be of therapeutic value in diabetic encephalopathy.

LncRNA H19 regulates ID2 expression through competitive binding to hsa-miR-19a/b in acute myelocytic leukemia.

Acute myelocytic leukemia (AML) is the most common type of acute leukemia. Long non­coding RNAs (lncRNAs) serve an important role in regulating gene expression through chromatin modification, transcription and post­transcriptional processing. LncRNA H19 was considered as an independent prognostic marker for patients with tumors. The expression of lncRNA H19 was identified to be significantly upregulated in bone marrow samples from patients with AML­M2. Furthermore, it was demonstrated that the knockdown of lncRNA H19 resulted in increased expression of hsa­microRNA (miR)­19a/b and decreased expression of inhibitor of DNA binding 2 (ID2) in AML cells. The knockdown of lncRNA H19 inhibited the proliferation of AML cells in vitro, which could be partially reversed by ID2 overexpression. Furthermore, the results of the bioinformatic analysis revealed potential hsa­miR­19a/b­3p binding sites in lncRNA H19 and ID2. Altogether, the results of the present study suggest that lncRNA H19 regulates the expression of ID2 through competitive binding to hsa­miR­19a and hsa­miR­19b, which may serve a role in AML cell proliferation.