High-Glucose-Induced Injury to Proximal Tubules of the Renal System Is Alleviated by Netrin-1 Suppression of Akt/mTOR.

The kidneys have a high level of Netrin-1 expression, which protects against some acute and chronic kidney disorders. However, it is yet unknown how Netrin-1 affects renal proximal tubule cells in diabetic nephropathy (DN) under pathological circumstances. Research has shown that autophagy protects the kidneys in animal models of renal disease. In this study, we looked at the probable autophagy regulation mechanism of Netrin-1 and its function in the pathogenesis of DN. We proved that in HK-2 cell, high blood sugar levels caused Netrin-1 to be downregulated, which then triggered the Akt/mTOR signaling pathway and enhanced cell death and actin cytoskeleton disruption. By adding Netrin-1 or an autophagy activator in vitro, these pathogenic alterations were reverted. Our results indicate that Netrin-1 stimulates autophagy by blocking the Akt/mTOR signaling pathway, which underlies high-glucose-induced malfunction of the renal proximal tubules. After HK-2 cells were incubated with Netrin-1 recombination protein and rapamycin under HG conditions for 24 h, the apoptosis was significantly reduced, as shown by the higher levels of Bcl-2, as well as lower levels of Bax and cleaved caspase-3 (P = 0.012, Cohen's d = 0.489, Glass's delta = 0.23, Hedges' g = 0.641). This study reveals that targeting Netrin-1-related signaling has therapeutic potential for DN and advances our knowledge of the processes operating in renal proximal tubules in DN.

Uric acid is independently associated with interleukin-1ß levels in tear fluid of hyperuricemia and gout patients.

OBJECTIVES: To explore pro-inflammatory cytokines status in the tear fluid of patients with hyperuricemia and gout and its association with uric acid level. METHODS: A total of 58 control subjects, 58 hyperuricemia patients including 40 asymptomatic hyperuricemia and 18 gout participants were recruited in this study. For tear analysis, each patient's tears were collected using capillary action microcaps after stimulation. Tear uric acid levels were measured using chemiluminescence. Tear and serum interleukin-1beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) levels were measured using enzyme-linked immunosorbent assay. The correlation of serum and tear uric acid levels with IL-1ß and TNF-α were determined. RESULTS: Tear uric acid levels were significantly higher in hyperuricemia group (98.2 ± 51.5 vs. 42.7 ± 24.0 µmol/L, p < .001) than in controls group. IL-1ß concentrations were significantly higher in hyperuricemia eyes compared to control eyes (210.2 ± 113.9 vs. 142.6 ± 29.8 pg/mL, p < .001). Multiple linear regression analysis showed that tear uric acid levels were independently positively associated with tear IL-1ß concentrations (B = 0.192, p < .001). However, no significant correlations were found between serum or tear uric acid and TNF-α level. Moreover, there were no statistically differences of tear IL-1ß and TNF-α levels between the asymptomatic hyperuricemia and gout groups. CONCLUSIONS: Tear uric acid levels were higher in patients with hyperuricemia and gout than in controls. There was a significant positive correlation between tear uric acid value and tear IL-1ß level, implying an interaction between hyperuricemia and ocular inflammation responses.

Autoimmune polyglandular syndrome type 1 with diabetes insipidus: a case report.

BACKGROUND: Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare monogenic inherited disease caused by mutations of the autoimmune regulator gene (AIRE). The three major components of this syndrome are chronic mucocutaneous candidiasis, hypoparathyroidism and adrenocortical insufficiency. CASE PRESENTATION: We report a 20-year-old male who was clinically diagnosed with APS-1 at the age of 15. He was admitted to our department this time for suffering from polyuria and polydipsia for 6 months and was finally diagnosed with diabetes insipidus. Whole-exome sequencing (WES) revealed a novel compound heterozygous mutation of the AIRE gene -the c.239 T > G (p.Val80Gly) variant on one allele and the copy number variant (CNV) of 21q22.3(chr21:45,670,150-45,706,528)*1 on the other. CONCLUSIONS: This case suggests that diabetes insipidus is a rare component of APS-1 and expands the variety of mutations on AIRE gene.

JAB1 promotes palmitate-induced insulin resistance via ERK pathway in hepatocytes.

Insulin resistance (IR) is the primary pathological mechanism underlying Type 2 diabetes mellitus (T2DM). Many researches have reported the relationship between chronic inflammation and IR, while the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway is rapidly activated in inflammatory conditions. However, the functional role of ERK1/2 in IR remains to be identified. We here reported that C-Jun activation domain-binding protein-1 (JAB1) was upregulated in IR. In addition, we showed that depletion of JAB1 led to recovery of insulin sensitivity. Given the fact that JAB1 played as an activator of ERK1/2, we assumed JAB1 was involved in IR through ERK pathway. So we assessed the effects of JAB1 knockdown in palmitate acid (PA) treated HepG2 cells. Importantly, JAB1 siRNA blocked the effect of PA-induced activation of ERK1/2. Furthermore, silencing of JAB1 could reduce the release of inflammatory factors, facilitate hepatic glucose uptake and improve lipid metabolism. All these data implicated that JAB1 knockdown might alleviate PA-induced IR through ERK pathway in hepatocytes.

Serum adropin levels are decreased in Chinese type 2 diabetic patients and negatively correlated with body mass index.

Adropin has been identified as potent regulatory hormone implicated in insulin sensitivity and the maintenance of energy homeostasis. The aim of current study was to investigate serum adropin concentrations of type 2 diabetes mellitus (T2DM) patients in the fasting status, especially those overweight/obese and evaluate the relationships between adropin levels and metabolic parameters. A total of 116 T2DM patients and 60 controls with normal glucose tolerance (NGT) were recruited to the study. Adropin concentration was determined using commercial ELISA kits. Anthropometric characteristics were collected and biochemistry, glycosylated hemoglobin A1c (HbA1c) and fasting insulin (FIns) were detected by clinical laboratory. Insulin resistance was estimated by homeostasis model 2 assessment of insulin resistance (HOMA2-IR). Serum adropin levels in Chinese T2DM patients were decreased compared with the controls [3.8 (3.0-5.5) vs. 5.5 (3.7-7.9) ng/mL, p < 0.01]. Meanwhile, overweight/obese patients had more considerably reduced levels of adropin. Adropin level was negatively correlated with body mass index (BMI), high-sensitive C reactive protein (hs-CRP), triglycerides (TG), fasting plasma glucose (FPG), FIns, HOMA2-IR and HbA1c, while positively with high-density lipoprotein cholesterol (HDL-C) in study participants (p < 0.01). The correlations of adropin with glucolipid variables (TG, HDL-C, FPG, FIns, HOMA2-IR, HbA1c) still existed after adjusting the effect of BMI. Besides, HOMA2-IR and HbA1c were independent factors associated with serum adropin levels. Binary logistic regression analyses showed that adropin was significantly associated with T2DM after removing confounding factors (p < 0.01). Receiver operating characteristic (ROC) curve demonstrated adropin concentration of 5.8 ng/mL could be used as a possible optimal cut-off value to identify T2DM from non-T2DM with sensitivity of 81.9% and specificity of 46.7%. Serum adropin concentrations are decreased in Chinese T2DM patients, especially those overweight/obese. Adropin, associated with glucolipid homeostasis and insulin sensitivity, may implicate in the pathogenesis of T2DM.