Key enzyme in charge of ketone reabsorption of renal tubular SMCT1 may be a new target in diabetic kidney disease.

OBJECTIVE: A ketogenic diet or mildly increased ketone body levels are beneficial for diabetic kidney disease (DKD) patients. Our previous study has found that sodium-coupled monocarboxylate transporter 1 (SMCT1), a key enzyme in charge of ketone reabsorption, possesses beneficial effects on the function of renal tubular epithelial cells (TECs) in energy crisis. Our present study is to investigate whether SMCT1 is important in maintaining the physiological function of renal tubular and plays a role in DKD. METHODS: We tested the expression of SMCT1 in kidney tissues from DKD patients receiving kidney biopsy as well as diabetes mice. We compared the difference of ß-hydroxybutyrate (ß-HB) levels in serum, urine and kidney tissues between diabetic mice and control. Using recombinant adeno-associated viral vector containing SMCT1 (encoded by Slc5a8 gene), we tested the effect of SMCT1 upregulation on microalbuminuria as well as its effects on mitochondrial energy metabolism in diabetic mice. Then we investigated the role of SMCT1 and its ß-HB reabsorption function in maintaining the physiological function of renal tubular using renal tubule-specific Slc5a8 gene knockout mice. Transcriptomes and proteomics analysis were used to explore the underlying mechanism. RESULTS: SMCT1 downregulation was found in DKD patients as well as in diabetic mice. Moreover, diabetic mice had a decreased renal ß-HB level compared with control, and SMCT1 upregulation could improve microalbuminuria and mitochondrial energy metabolism. In renal tubule-specific Slc5a8 gene knockout mice, microalbuminuria occurred early at 24 weeks of age, accompanied by ATP shortage and metabolic reprogramming in the kidney; however, supplementation with ß-HB precursor substance 1,3-butanediol in food alleviated kidney damage as well as energy metabolic reprogramming. CONCLUSIONS: Decreased SMCT1 expression and its ketone reabsorption function play an important role in the occurrence of DKD. SMCT1 may be a new promising target in treating DKD.

A J-shaped relationship between ketones and the risk of diabetic kidney disease in patients with type 2 diabetes: New insights from a cross-sectional study.

AIM: To investigate the association between circulating ß-hydroxybutyric acid (ßOHB) and diabetic kidney disease (DKD) risk in patients with type 2 diabetes (T2D). MATERIALS AND METHODS: A total of 1388 patients with T2D were recruited. Participants were divided into high and normal ßOHB groups. Participants in the normal ßOHB group were divided into four subgroups according to ßOHB quartile (Q). The relationships of ßOHB with DKD and DKD subtype were analysed using chi-square and binary logistic regression. Restricted cubic splines were used to explore the non-linear correlation between ßOHB concentration and DKD risk in the total population. RESULTS: A higher prevalence of DKD was detected in the high compared with the normal ßOHB group (43.3% vs. 33.3%, P = .041). Participants in the Q4 group (ßOHB, 0.12-0.30 mM) had the lowest prevalence of DKD (P = .001). In the binary logistic regression model, the multivariable-adjusted odds ratios (ORs) (95% confidence intervals [CIs]) for DKD risk were 2.30 (1.62-3.26) for Q1, 1.80 (1.23-2.62) for Q2 and 1.63 (1.10-2.41) for Q3 relative to Q4 (P < .001). Restricted cubic spline analyses suggested a J-shaped association of circulating ßOHB concentration with DKD risk. DKD risk was lowest at a serum ßOHB concentration of 0.183 mM (OR, 0.63; 95% CI, 0.52-0.77). CONCLUSIONS: A J-shaped relationship between circulating ketone level and DKD risk in patients with T2D was determined. Circulating ßOHB in the range of 0.12-0.30 mM was associated with a lower risk of DKD. Further studies are warranted to verify the causality and to elucidate the underlying mechanisms.

Urine Immunoglobin G Greater Than 2.45 mg/L Has a Correlation with the Onset and Progression of Diabetic Kidney Disease: A Retrospective Cohort Study.

AIM: To further assess the correlation between urine immunoglobin G (IgG) greater than 2.45 mg/L and the onset and progression of diabetic kidney disease (DKD). METHODS: One thousand and thirty-five patients with type 2 diabetes mellitus (T2DM) were divided into two groups based on the baseline levels of 24 h urinary albumin excretion (24 h UAE): one group with 24 h UAE < 30 mg/24 h and one with 24 h UAE ≥ 30 mg/24 h. The groups were subdivided using baseline levels of urine IgG (≤2.45 mg/L and >2.45 mg/L; hereafter, the Low and High groups, respectively). We used logistic regression to assess the risk of urine IgG and it exceeding 2.45 mg/L. Kaplan-Meier curves were used to compare the onset and progression time of DKD. The receiver operating characteristic curve was used to test the predictive value of urine IgG exceeding 2.45 mg/L. RESULTS: Urine IgG was an independent risk factor for the onset and progression of DKD. The rate and risk of DKD onset and progression at the end of follow-up increased significantly in the High group. The onset and progression time of DKD was earlier in the High group. Urine IgG exceeding 2.45 mg/L has a certain predictive value for DKD onset. CONCLUSIONS: Urine IgG exceeding 2.45 mg/L has a correlation with the onset and progression of DKD, and it also has a certain predictive value for DKD onset.

Establishment and validation of the cut-off values of estimated glomerular filtration rate and urinary albumin-to-creatinine ratio for diabetic kidney disease: A multi-center, prospective cohort study.

Objective: We aimed to study the cut-off values of estimated glomerular filtration rate (eGFR) and the urinary albumin creatinine ratio (UACR) in the normal range for diabetic kidney disease (DKD). Methods: In this study, we conducted a retrospective, observational cohort study included 374 type 2 diabetic patients who had baseline eGFR ≥60 mL/min/1.73 m2 and UACR <30 mg/g with up to 6 years of follow-up. The results were further validated in a multi-center, prospective cohort study. Results: In the development cohort, baseline eGFR (AUC: 0.90, cut-off value: 84.8 mL/min/1.73 m2, sensitivity: 0.80, specificity: 0.85) or UACR (AUC: 0.74, cut-off value: 15.5mg/g, sensitivity: 0.69, specificity: 0.63) was the most effective single predictor for DKD. Moreover, compared with eGFR or UACR alone, the prediction model consisted of all of the independent risk factors did not improve the predictive performance (P >0.05). The discrimination of eGFR at the cut-off value of 84.80 mL/min/1.73 m2 or UACR at 15.5mg/g with the largest Youden's index was further confirmed in the validation cohort. The decrease rate of eGFR was faster in patients with UACR ≥15.5mg/g (P <0.05). Furthermore, the decrease rate of eGFR or increase rate of UACR and the incidence and severity of cardiovascular disease (CVD) were higher in patients with eGFR ≤84.8 mL/min/1.73 m2 or UACR ≥15.5mg/g (P <0.05). Conclusions: In conclusion, eGFR ≤84.8mL/min/1.73 m2 or UACR ≥15.5mg/g in the normal range may be an effective cut-off value for DKD and may increase the incidence and severity for CVD in type 2 diabetic patients.

Beta-Hydroxybutyric Acid Inhibits Renal Tubular Reabsorption via the AKT/DAB2/Megalin Signalling Pathway.

Aim: Patients with diabetic ketosis often exhibit albuminuria. We previously found that acute hyperglycaemia can cause nephrotoxic injury. Here, we explored whether an excessive ketone body level causes kidney injury and the potential underlying mechanism. Methods: Fifty-six type 2 diabetes without ketosis (NDK group), 81 type 2 diabetes with ketosis (DK group), and 38 healthy controls (NC group) were enrolled. Clinical data were collected before and after controlling diabetic ketosis. Beta-hydroxybutyric acid (BOHB), an AKT activator, an AKT inhibitor, or plasmids encoding DAB2 were transformed into human renal proximal tubule epithelial cells (HK-2 cells). Results: The urinary albumin-to-creatinine ratio (ACR), transferrin (TF), immunoglobulin G (IgG), Beta2-microglobulin (ß2-MG), retinol-binding protein (RBP), N-acetyl-beta-glucosaminidase (NAG), and Beta-galactosidase (GAL) were higher in the DK than NC and NDK groups. The proportion of patients with an increased urinary level of TF, IgG, ß2-MG, RBP, NAG, or GAL was higher in the DK group too. After controlling ketosis, urinary microalbumin, TF, IgG, ß2-MG, and RBP decreased significantly. In HK-2 cells, albumin endocytosis and megalin expression decreased with increasing BOHB concentration. Compared with BOHB treatment, BOHB with AKT activator significantly increased the DAB2, megalin levels and albumin endocytosis; the AKT inhibitor treatment exhibited the opposite effects. Compared with BOHB treatment, megalin expression and albumin endocytosis were significantly increased after BOHB with DAB2 overexpression treatment. Conclusions: Patients with diabetic ketosis may suffer from glomerular and tubular injuries that recover after ketosis control. High concentrations of BOHB downregulate megalin expression by inhibiting the AKT/DAB2/megalin signalling pathway and albumin endocytosis in proximal renal tubules.

Hyperinsulinemia impairs the metabolic switch to ketone body utilization in proximal renal tubular epithelial cells under energy crisis via the inhibition of the SIRT3/SMCT1 pathway.

Objective: To investigate the effects and mechanism of hyperinsulinemia on the metabolic switch to ß-hydroxybutyrate (BHB) absorption and utilization under a starvation or hypoxic environment in proximal tubular epithelial cells. Methods: A high-fat diet-induced hyperinsulinemia model in ZDF rats was used to test the expression of key enzymes/proteins of ketone body metabolism in the kidney. Notably, 12-week-old renal tubule SMCT1 specific knockout mice (SMCT1 flox/floxCre+) and control mice (SMCT1 flox/floxCre-) were used to confirm the roles of SMCT1 in kidney protection under starvation. The changes of key enzymes/proteins of energy metabolism, mitochondrial function, and albumin endocytosis in HK2 cells under low glucose/hypoxic environments with or without 50 ng/mL insulin were studied. Silent information regulation 2 homolog 3 (SIRT3) was overexpressed to evaluate the effect of hyperinsulinemia on the metabolic switch to BHB absorption and utilization through the SIRT3/SMCT1 pathway in HK2 cells. Results: In ZDF rats, the expression of HMGCS2 increased, the SMCT1 expression decreased, while SCOT remained unchanged. In renal tubule SMCT1 gene-specific knockout mice, starvation for 48 h induced an increase in the levels of urine retinol-binding protein, N-acetyl-ß-glucosaminidase, and transferrin, which reflected tubular damages. In HK2 cells under an environment of starvation and hypoxia, the levels of key enzymes related to fatty acid oxidation and ketone body metabolism were increased, whereas glucose glycolysis did not change. The addition of 2 mmol/l BHB improved ATP production, mitochondrial biosynthesis, and endocytic albumin function, while cell apoptosis was reduced in HK2 cells. The addition of 50 ng/ml insulin resulted in the decreased expression of SMCT1 along with an impaired mitochondrial function, decreased ATP production, and increased apoptosis. The overexpression of SIRT3 or SMCT1 reversed these alterations induced by a high level of insulin both in low-glucose and hypoxic environments. Conclusions: The increased absorption and utilization of BHB is part of the metabolic flexibility of renal tubular epithelial cells under starvation and hypoxic environments, which exhibits a protective effect on renal tubular epithelial cells by improving the mitochondrial function and cell survival. Moreover, hyperinsulinemia inhibits the absorption of BHB through the inhibition of the SIRT3/SMCT1 pathway.

Sex-specific mediating effect of gestational weight gain between pre-pregnancy body mass index and gestational diabetes mellitus.

BACKGROUND: Inappropriate weight gain may increase the risk of gestational diabetes mellitus (GDM). However, the relationship between pre-pregnancy body mass index (BMI), weight gain, and GDM has not been precisely quantified. This study aimed to explore whether gestational weight gain played a mediating role between pre-pregnancy BMI and GDM and whether the mediating effect was sex specific. METHODS: This study established a population-based observational cohort to assess weight gain in pregnant women. Mediation analyses were performed to quantify whether weight gain mediated the association between pre-pregnancy BMI and GDM. RESULTS: A total of 67,777 pregnant women were included in the final analysis, among whom 6751 (10.0%) were diagnosed with GDM. We verified that both pre-pregnancy BMI and weight gain were associated with GDM, and that BMI negatively contributed to weight gain. We also found that weight gain had a significant mediating effect on the relationship between pre-pregnancy BMI and GDM (Za × Zb confidence intervals [CIs] 0.00234-0.00618). Furthermore, the effect was sex-specific, in that it was only significant in overweight women carrying female fetuses (Za × Zb CIs 0.00422-0.01977), but not male fetuses (Za × Zb CIs -0.00085 to 0.01236). CONCLUSIONS: Weight gain during pregnancy had a fetal sex-specific mediating effect between pre-pregnancy BMI and GDM.

Reductions in Intestinal Taurine-Conjugated Bile Acids and Short-Chain Fatty Acid-Producing Bacteria Might be Novel Mechanisms of Type 2 Diabetes Mellitus in Otsuka Long-Evans Tokushima Fatty Rats.

BACKGROUND: The pathogenesis of spontaneously diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats, among the best models for human type 2 diabetes mellitus (T2DM), remains poorly defined. Therefore, we investigated the dynamic changes in taurine-conjugated bile acids (T-BAs) and intestinal microbiota during T2DM development in OLETF rats. METHODS: OLETF rats and corresponding diabetes-resistant Long Evans Tokushima Otsuka (LETO) rats were fed a normal baseline diet. The progress of T2DM was divided into four phases, including normal glycemia-normal insulinemia (baseline), normal glycemia-hyperinsulinemia, impaired glucose tolerance, and DM. Body weight, liver function, blood lipids, fasting plasma glucose, fasting plasma insulin, fasting plasma glucagon-like peptide (GLP)-1 and GLP-2, serum and fecal T-BAs, and gut microbiota were analyzed during the entire course of T2DM development. RESULTS: There were reductions in fecal T-BAs and short-chain fatty acids (SCFAs)-producing bacteria including Phascolarctobacterium and Lactobacillus in OLETF rats compared with those in LETO rats at baseline, and low levels of fecal T-BAs and SCFAs-producing bacteria were maintained throughout the whole course of the development of T2DM among OLETF rats compared with those in corresponding age-matched LETO rats. Fecal taurine-conjugated chenodeoxycholic acid correlated positively with Phascolarctobacterium. Fecal taurine-conjugated deoxycholic acid correlated positively with Lactobacillus and fasting plasma GLP-1 and inversely with fasting plasma glucose. CONCLUSION: The fecal BAs profiles and microbiota structure among OLETF rats were different from those of LETO rats during the entire course of T2DM development, indicating that reductions in intestinal T-BAs and specific SCFA-producing bacteria may be potential mechanisms of T2DM in OLETF rats.

Retinal Neuropathy in IGT Stage of OLETF Rats: Another Characteristic Change of Diabetic Retinopathy.

AIMS: We investigated the changes of retinal structure in normal glucose tolerance (NGT), impaired glucose tolerance (IGT), diabetes mellitus (DM), and diabetic kidney disease (DKD) stages in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS: We assigned OLETF rats to four groups based on their OGTT results and 24 h urinary microalbumin (24 h UMA) levels: NGT, IGT, DM, and DKD groups. We observed the structural and the corresponding pathological changes and quantified the expression of HIF-1α, iNOS, NF-κB, VEGF, ICAM-1, and occludin in the retina. RESULTS: Significant damage to the retinal structure, especially in retinal ganglion cells (RGCs), was observed in the IGT stage. The expression of HIF-1α, iNOS, NF-κB, VEGF, and ICAM-1 was significantly upregulated, while that of occludin was downregulated. CONCLUSION: Significant retinal neuropathy occurs in the IGT stage. Inflammation and hypoxia may damage the blood retina barrier (BRB), leading to diabetic retinopathy.

Berberine Slows the Progression of Prediabetes to Diabetes in Zucker Diabetic Fatty Rats by Enhancing Intestinal Secretion of Glucagon-Like Peptide-2 and Improving the Gut Microbiota.

Background: Berberine is a plant alkaloid that has multiple beneficial effects against intestine inflammation. In our previous study, we have found that berberine also possesses an antidiabetic effect. However, whether berberine is useful in the prevention of type 2 diabetes mellitus (T2DM) through its effect on intestine endocrine function and gut microbiota is unclear. Aim: To investigate the effects of berberine in the prevention of T2DM, as well as its effects on intestine GLP-2 secretion and gut microbiota in ZDF rats. Methods: Twenty Zucker Diabetic Fatty (ZDF) rats were fed a high-energy diet until they exhibited impaired glucose tolerance (IGT). The rats were then divided into two groups to receive berberine (100 mg/kg/d; berberine group) or vehicle (IGT group) by gavage for 3 weeks. Five Zucker Lean (ZL) rats were used as controls. Fasting blood glucose (FBG) was measured, an oral glucose tolerance test was performed, and the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) was calculated. Intestinal expression of TLR-4, NF-κB, TNF-α, mucin, zona occludens-1 (ZO-1) and occludin were assessed (immunohistochemistry). Plasma levels and glutamine-induced intestinal secretion of glucagon-like peptide-1 (GLP-1) and GLP-2 were measured (enzyme-linked immunosorbent assay). The plasma lipopolysaccharide (LPS) level was measured. Fecal DNA extraction, pyrosequencing, and bioinformatics analysis were performed. Results: After 3 weeks of intervention, diabetes developed in all rats in the IGT group, but only 30% of rats in the berberine group. Treatment with berberine was associated with reductions in food intake, FBG level, insulin resistance, and plasma LPS level, as well as increases in fasting plasma GLP-2 level and glutamine-induced intestinal GLP-2 secretion. Berberine could increase the goblet cell number and villi length, and also reverse the suppressed expressions of mucin, occludin, ZO-1 and the upregulated expressions of TLR-4, NF-κB and TNF-α induced in IGT rats (P<0.05). Berberine also improved the structure of the gut microbiota and restored species diversity. Conclusion: Berberine may slow the progression of prediabetes to T2DM in ZDF rats by improving GLP-2 secretion, intestinal permeability, and the structure of the gut microbiota.

Pathological Hyperinsulinemia and Hyperglycemia in the Impaired Glucose Tolerance Stage Mediate Endothelial Dysfunction Through miR-21, PTEN/AKT/eNOS, and MARK/ET-1 Pathways.

Background: Impaired glucose tolerance (IGT) is an important prediabetic stage characterized by elevated concentrations of glucose and insulin in the blood. The pathological hyperglycemia and hyperinsulinemia in IGT may regulate the expression of microRNA-21 (miR-21) and affect the downstream insulin signaling pathways, leading to endothelial cell dysfunction and early renal damage. Methods: The individual and combined effects of insulin and glucose were investigated using human glomerular endothelial cells (HGECs). The expression levels of miR-21, and PTEN/AKT/eNOS and MAPK/ET-1 pathway proteins in the treated cells were measured. The levels of nitric oxide (NO) and endothelin-1 (ET-1) secreted by the cells were also measured. The role of miR-21 in mediating the regulatory effects of insulin and glucose was assessed by overexpression/inhibition of this miRNA using mimics/inhibitor. Results: High (>16.7 mmol/L) concentration of glucose upregulated the expression of miR-21, leading to the activation and inhibition of the PTEN/AKT/eNOS and MAPK/ET-1 pathways, and upregulation of NO and downregulation of ET-1 secretion, respectively. High (>25 ng/mL) concentration of insulin downregulated the expression of miR-21, and lead to the activation of the MAPK/ET-1 and inhibition of the PTEN/AKT/eNOS pathway, thereby upregulating the expression of ET-1 and downregulating the secretion of NO. MiR-21 was observed to play a key role by directly controlling the activation of the insulin signaling pathways when the cells were cotreated with different concentrations of insulin and glucose. The expression of miR-21 was found to be dependent on the relative concentration of insulin and glucose. Under simulated conditions of the IGT stage (8.3 mmol/L glucose + 50 ng/mL insulin), the inhibitory effect of high insulin concentration on miR-21 expression in the cells attenuated the activation by high glucose concentration, resulting in the downregulation of miR-21, upregulation of ET-1 and downregulation of NO secretion. Conclusion: Taken together, these results indicate that high insulin and glucose concentrations regulate the secretory function of glomerular endothelial cells in opposite ways by regulating the expression of miRNA-21. Pathological concentrations of insulin and glucose in the IGT stage may lead to a decrease in miR-21 expression, thereby disordering the secretion of vasoactive factors, resulting in renal tubule ischemia.

Different Appearance of Chest CT Images of T2DM and NDM Patients with COVID-19 Pneumonia Based on an Artificial Intelligent Quantitative Method.

COVID-19 is a kind of pneumonia with new coronavirus infection, and the risk of death in COVID-19 patients with diabetes is four times higher than that in healthy people. It is unclear whether there is a difference in chest CT images between type 2 diabetes mellitus (T2DM) and non-diabetes mellitus (NDM) COVID-19 patients. The aim of this study was to investigate the differences in chest CT images between T2DM and NDM patients with COVID-19 based on a quantitative method of artificial intelligence. A total of 62 patients with COVID-19 pneumonia were retrospectively enrolled and divided into group A (T2DM COVID-19 pneumonia group, n = 15) and group B (NDM COVID-19 pneumonia group, n = 47). The clinical and laboratory examination information of the two groups was collected. Quantitative features (volume of consolidation shadows and ground glass shadows, proportion of consolidation shadow (or ground glass shadow) to lobe volume, total volume, total proportion, and number) of chest spiral CT images were extracted using Dr. Wise @Pneumonia software. The results showed that among the 26 CT image features, the total volume and proportion of bilateral pulmonary consolidation shadow in group A were larger than those in group B (P=0.031 and 0.019, respectively); there was no significant difference in the total volume and proportion of bilateral pulmonary ground glass density shadow between the two groups (P > 0.05). In group A, the blood glucose level was correlated with the volume of consolidation shadow and the proportion of consolidation shadow to right middle lobe volume, and higher than those patients in group B. In conclusion, the inflammatory exudation in the lung of COVID-19 patients with diabetes is more serious than that of patients without diabetes based on the quantitative method of artificial intelligence. Moreover, the blood glucose level is positively correlated with pulmonary inflammatory exudation in COVID-19 patients.

Vildagliptin Attenuates Myocardial Dysfunction and Restores Autophagy via miR-21/SPRY1/ERK in Diabetic Mice Heart.

Aim: Vildagliptin (vild) improves diastolic dysfunction and is associated with a lower relative risk of major adverse cardiovascular events in younger patients. The present study aimed to evaluate whether vild prevents the development of diabetic cardiomyopathy in type 2 diabetic mice and identify its underlying mechanisms. Methods: Type 2 diabetic mouse model was generated using wild-type (WT) (C57BL/6J) and miR-21 knockout mice by treatment with HFD/STZ. Cardiomyocyte-specific miR-21 overexpression was achieved using adeno-associated virus 9. Echocardiography was used to evaluate cardiac function in mice. Morphology, autophagy, and proteins levels in related pathway were analyzed. qRT-PCR was used to detect miR-21. Rat cardiac myoblast cell line (H9c2) cells were transfected with miR-21 mimics and inhibitor to explore the related mechanisms of miR-21 in diabetic cardiomyopathy. Results: Vild restored autophagy and alleviated fibrosis, thereby enhancing cardiac function in DM mice. In addition, miR-21 levels were increased under high glucose conditions. miR-21 knockout DM mice with miR-21 knockout had reduced cardiac hypertrophy and cardiac dysfunction compared to WT DM mice. Overexpression of miR-21 aggravated fibrosis, reduced autophagy, and attenuated the protective effect of vild on cardiac function. In high-glucose-treated H9c2 cells, the downstream effectors of sprouty homolog 1 (SPRY1) including extracellular signal-regulated kinases (ERK) and mammalian target of rapamycin showed significant changes following transfection with miR-21 mimics or inhibitor. Conclusion: The results of our study indicate that vild prevents DCM by restoring autophagy through the miR-21/SPRY1/ERK/mTOR pathway. Therefore, miR-21 is a target in the development of DCM, and vild demonstrates significant potential for clinical application in prevention of DCM.

Bisecting GlcNAc modification diminishes the pro-metastatic functions of small extracellular vesicles from breast cancer cells.

Small extracellular vesicles (sEVs) are enriched in glycoconjugates and display specific glycosignatures. Aberrant expression of surface glycoconjugates is closely correlated with cancer progression and metastasis. The essential functions of glycoconjugates in sEVs are poorly understood. In this study, we observed significantly reduced levels of bisecting GlcNAc in breast cancer. Introduction of bisecting GlcNAc into breast cancer cells altered the bisecting GlcNAc status on sEVs, and sEVs with diverse bisecting GlcNAc showed differing functions on recipient cells. Carcinogenesis and metastasis of recipient cells were enhanced by sEVs with low bisecting GlcNAc, and the pro-metastatic functions of sEVs was diminished by high bisecting GlcNAc modification. We further identified vesicular integrin ß1 as a target protein bearing bisecting GlcNAc. Metastasis of recipient cells was strongly suppressed by high bisecting GlcNAc levels on vesicular ß1. Our findings demonstrate the important roles of glycoconjugates on sEVs. Modification of sEV glycosylation may contribute to development of novel targets in breast cancer therapy.

Hyperinsulinemia contributes to impaired-glucose-tolerance-induced renal injury via mir-7977/SIRT3 signaling.

BACKGROUND: Increasing evidence indicates that impaired glucose tolerance (IGT) is independently associated with chronic kidney disease, but the characteristics and underlying mechanisms remain largely unknown. METHODS: Here, the cross-sectional study was performed to study the characteristics of IGT-induced renal injury (IGT-RI). Furthermore, urine microRNA profile was evaluated and microRNAs involved in tubular injury were determined by in-vitro experiments. RESULTS: It was found that 12.1% of IGT patients had microalbuminuria, which we termed "IGT-RI." Overall, 100% of patients with IGT-RI exhibited reabsorption dysfunction and 58.3% had structural damage in the renal tubules. Two-hour postprandial insulin, retinol-binding protein, and N-acetyl-ß-glucosaminidase were significantly associated with microalbuminuria and they were independent risk factors for IGT-RI. The expression of mir-7977 was altered in IGT-RI patients and may be involved in cellular response to oxidative stress. In proximal tubule epithelial cells in vitro, a high level of insulin increased the expression of mir-7977 and decreased that of sirtuin 3 (SIRT3), leading to oxidative stress. Overexpression of mir-7977 further decreased SIRT3 expression, whereas inhibition of mir-7977 had the opposite effect. Furthermore, mir-7977 can bind to the 3'-untranslated region of SIRT3 mRNA and inhibit its expression. Moreover, inhibition of SIRT3 reduced the expression of cubilin and the endocytosis of albumin. CONCLUSIONS: In conclusion, IGT-RI mainly manifests as tubular injury, especially reabsorption dysfunction. Compensatory hyperinsulinemia may be involved. A high level of insulin can activate mir-7977/SIRT3 signaling, resulting in tubular injury by inducing oxidative stress as well as reabsorption dysfunction by inhibiting the expression of cubilin, ultimately contributing to IGT-RI.

Hsa_Circ_0007841 Enhances Multiple Myeloma Chemotherapy Resistance Through Upregulating ABCG2.

The current researches have reported that circular RNA is an important regulatory factor in the progression of various human disease. However, the function and mechanism of most circular RNAs remain unknown in cancers including multiple myeloma. Our study has confirmed that hsa_circ_0007841 is up regulated in U266 doxorubicin resistant cells (U266R) and 8226 doxorubicin resistant cells (8226R) compared to U266 parent cells (U266P) and 8226 parent cells (8226P). Silence of hsa_circ_0007841 in U266R and 8226R could reduce the half-maximal inhibitory concentration which indicated reduction in chemoresistance. In doxorubicin resistant cells, the messenger RNA and protein level of ATP-binding cassette transporters G2 increased. Silence of hsa_circ_0007841 in drug resistant cells could decrease both the messenger RNA and protein levels of ATP-binding cassette transporters G2; reexpression of hsa_circ_0007841 could block the reduction. However, overexpression of hsa_circ_0007841 could effectively upregulate the ATP-binding cassette transporters G2 messenger RNA and protein level. Inhibition of ATP-binding cassette transporters G2 could block hsa_circ_0007841 overexpression induced chemoresistance in U266P and 8226P cells. What's more, inhibition of ATP-binding cassette transporters G2 could reduce differences of half-maximal inhibitory concentration between parent cell lines and drug-resistant cell lines. Our data collectively suggest a new model in which hsa_circ_0007841 promotes acquired chemotherapy resistance by upregulating ATP-binding cassette transporters G2 providing a novel molecular basis of chemotherapy in multiple myeloma cancer.

Preventive Role of Salsalate in Diabetes Is Associated With Reducing Intestinal Inflammation Through Improvement of Gut Dysbiosis in ZDF Rats.

A safe and effective approach is needed to prevent and reduce the incidence of diabetes worldwide. The hypoglycemic efficacy of salicylic acid (salsalate, SAL), which has anti-inflammatory properties, has been empirically demonstrated in studies conducted at the Joslin Diabetes Center and elsewhere. Here, we investigated the potential role of SAL in preventing the onset of diabetes in Zucker diabetic fatty (ZDF) rats and attempted to elucidate its underlying mechanisms. ZDF and Zucker lean (ZL) rats were administered a high-fat diet with or without SAL intervention, and their relative rates of diabetes were compared. Our results showed that all rats in the placebo group developed diabetes, whereas only 10% of the SAL-treated rats presented with impaired glucose tolerance (IGT). None of the latter progressed to diabetes. Relative to the untreated rats, SAL lowered plasma glucagon and insulin while improving insulin sensitivity and ß-cell function. SAL may protect against hyperglycemia by increasing the microbial diversity, ameliorating gut dysbiosis, restoring intestinal epithelial cell connections, inhibiting endotoxin influx into the blood, and attenuating inflammation. Together, these findings suggest that SAL may be a candidate prophylactic therapy against diabetes. The protective role of SAL may be attributed to its ability to reduce intestinal inflammation and improve gut dysbiosis.

Establishment and Validation of a Risk Prediction Model for Early Diabetic Kidney Disease Based on a Systematic Review and Meta-Analysis of 20 Cohorts.

BACKGROUND: Identifying patients at high risk of diabetic kidney disease (DKD) helps improve clinical outcome. PURPOSE: To establish a model for predicting DKD. DATA SOURCES: The derivation cohort was from a meta-analysis. The validation cohort was from a Chinese cohort. STUDY SELECTION: Cohort studies that reported risk factors of DKD with their corresponding risk ratios (RRs) in patients with type 2 diabetes were selected. All patients had estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and urinary albumin-to-creatinine ratio (UACR) <30 mg/g at baseline. DATA EXTRACTION: Risk factors and their corresponding RRs were extracted. Only risk factors with statistical significance were included in our DKD risk prediction model. DATA SYNTHESIS: Twenty cohorts including 41,271 patients with type 2 diabetes were included in our meta-analysis. Age, BMI, smoking, diabetic retinopathy, hemoglobin A1c, systolic blood pressure, HDL cholesterol, triglycerides, UACR, and eGFR were statistically significant. All these risk factors were included in the model except eGFR because of the significant heterogeneity among studies. All risk factors were scored according to their weightings, and the highest score was 37.0. The model was validated in an external cohort with a median follow-up of 2.9 years. A cutoff value of 16 was selected with a sensitivity of 0.847 and a specificity of 0.677. LIMITATIONS: There was huge heterogeneity among studies involving eGFR. More evidence is needed to power it as a risk factor of DKD. CONCLUSIONS: The DKD risk prediction model consisting of nine risk factors established in this study is a simple tool for detecting patients at high risk of DKD.

HGF/c-Met Promote Renal Carcinoma Cancer Stem Cells Enrichment Through Upregulation of Cir-CCDC66.

Increasing studies have suggested that circular RNAs play an important function in the process of numerous cancers. We aimed to investigate the possible role of cir-CCDC66 in renal carcinoma cancer. As cancer stem cells are responsible for the renal carcinoma cancer tumor growth and resistance to conventional therapy, we focus on the cir-CCDC66 influence on renal carcinoma cancer stem cells. In this study, we performed experiments in human renal tubular epithelial cell HK2 cells and several renal carcinoma cancer cancer cell lines. The results showed that cir-CCDC66 was upregulated not only in renal carcinoma cancer cancer cell lines but also in cancer stem cell spheres. What's more, the results showed that cir-CCDC66 enhanced the cancer stem cell enrichment. Further mechanistic studies showed that hepatocyte growth factor/c-Met pathway was activated in cancer stem cell enrichment and responsible for the cir-CCDC66 upregulation. Inhibition of hepatocyte growth factor/c-Met could block cir-CCDC66-induced cancer stem cell enrichment. In conclusion, our research revealed a novel mechanism between hepatocyte growth factor/c-Met/cir-CCDC66 and cancer stem cell enrichment. We verified that cir-CCDC66 could be a promising biomarker and therapy target for renal carcinoma cancer treatment.