CD14 and CD26 from serum exosomes are associated with type 2 diabetes, exosomal Cystatin C and CD14 are associated with metabolic syndrome and atherogenic index of plasma

Identification of potential drug targets for diabetic polyneuropathy through Mendelian randomization analysis

BACKGROUND

Diabetic polyneuropathy (DPN) is a common diabetes complication with limited treatment options. We aimed to identify circulating plasma proteins as potential therapeutic targets for DPN using Mendelian Randomization (MR).

METHODS

The protein quantitative trait loci (pQTLs) utilized in this study were derived from seven previously published genome-wide association studies (GWASs) on plasma proteomics. The DPN data were obtained from the IEU OpenGWAS project. This study employed two-sample MR using MR-Egger and inverse-variance weighted methods to evaluate the causal relationship between plasma proteins and DPN risk, with Cochran's Q test, and I2 statistics, among other methods, used to validate the robustness of the results.

RESULTS

Using cis-pQTLs as genetic instruments, we identified 62 proteins associated with DPN, with 33 increasing the risk and 29 decreasing the risk of DPN. Using cis-pQTLs + trans-pQTLs, we identified 116 proteins associated with DPN, with 44 increasing the risk and 72 decreasing the risk of DPN. Steiger directionality tests indicated that the causal relationships between circulating plasma proteins and DPN were consistent with expected directions.

CONCLUSION

This study identified 96 circulating plasma proteins with genetically determined levels that affect the risk of DPN, providing new potential targets for DPN drug development, particularly ITM2B, CREG1, CD14, and PLXNA4.

High glucose induces DNA methyltransferase 1 dependent epigenetic reprogramming of the endothelial exosome proteome in type 2 diabetes

In response to hyperglycemia, endothelial cells (ECs) release exosomes with altered protein content and contribute to paracrine signalling, subsequently leading to vascular dysfunction in type 2 diabetes (T2D). High glucose reprograms DNA methylation patterns in various cell/tissue types, including ECs, resulting in pathologically relevant changes in cellular and extracellular proteome. However, DNA methylation-based proteome reprogramming in endothelial exosomes and associated pathological implications in T2D are not known. Hence, in the present study, we used Human umbilical vein endothelial cells (HUVECs), High Fat Diet (HFD) induced diabetic mice (C57BL/6) and clinical models to understand epigenetic basis of exosome proteome regulation in T2D pathogenesis . Exosomes were isolated by size exclusion chromatography and subjected to tandem mass tag (TMT) labelled quantitative proteomics and bioinformatics analysis. Immunoblotting was performed to validate exosome protein signature in clinically characterized individuals with T2D. We observed ECs cultured in high glucose and aortic ECs from HFD mouse expressed elevated DNA methyltransferase1 (DNMT1) levels. Quantitative proteomics of exosomes isolated from ECs treated with high glucose and overexpressing DNMT1 showed significant alterations in both protein levels and post translational modifications which were aligned to T2D associated vascular functions. Based on ontology and gene-function-disease interaction analysis, differentially expressed exosome proteins such as Thrombospondin1, Pentraxin3 and Cystatin C related to vascular complications were significantly increased in HUVECs treated with high glucose and HFD animals and T2D individuals with higher levels of glycated hemoglobin. These proteins were reduced upon treatment with 5-Aza-2'-deoxycytidine. Our study shows epigenetic regulation of exosome proteome in T2D associated vascular complications.

Lipid levels and insulin resistance markers in gastric cancer patients: diagnostic and prognostic significance

Gastric cancer (GC) is a highly heterogeneous and aggressive malignant tumor that seriously affects the life safety of people all over the world. Its early manifestations are subtle. The present study aimed to investigate the clinical significance of serum lipid profiles, insulin resistance markers including the triglyceride-glucose (TyG) index and the atherosclerotic index (AI), in GC patients. A retrospective analysis encompassed 215 GC patients and 827 healthy individuals. The study results show that the total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein levels, and the TyG index of GC patients were significantly lower than those of the control group before and after propensity score matching analysis. In the GC group, the levels of CEA, CA199, CA125, and CA724 tumor markers were higher than those in the healthy control group. Patients in advanced stages exhibited lower serum levels of serum lipids and TyG index compared to those in early stages. ROC analysis revealed that the TyG index, CA125, and CA199 combination yielded the highest positive prediction rate for GC at 98.6%. TyG index is significantly associated with the risk of adverse reactions after chemotherapy (OR = 1.104, 95% CI 1.028-1.186, P < 0.01). Multiple tumor markers and the TyG index combined detection showed correlations with five adverse reactions caused by chemotherapy (r < 0.6, P < 0.05). Preoperative lipid profiles in the serum show a strong correlation with patients diagnosed with GC. Evaluating a combination of various serum lipids and cancer markers significantly improves diagnostic precision for GC and the ability to predict chemotherapy side effects.

Soluble CD14 and Incident Diabetes Risk: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Context

Soluble CD14 (sCD14) is an inflammation biomarker with higher concentrations in White than Black adults. Higher sCD14 is seen in insulin resistance and diabetes. There are limited data on the relationship between sCD14 and incident diabetes.

Objective

To determine the association of sCD14 with incident diabetes risk in a large biracial US cohort and evaluate whether relationships differ by race.

Design

This study included 3401 Black and White participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study without baseline diabetes who completed baseline and follow-up in-home visits. Modified Poisson regression models estimated risk ratios (RR) of incident diabetes per 1-SD increment sCD14, with adjustment for risk factors. A sCD14-by-race interaction evaluated whether associations differed by race.

Results

There were 460 cases of incident diabetes over a mean 9.5 years of follow-up. The association of sCD14 with diabetes differed by race (P for interaction < .09). Stratifying by race, adjusting for age, sex, and region, higher sCD14 was associated with incident diabetes in White (RR: 1.15; 95% CI: 1.01, 1.33) but not Black participants (RR: 0.96; 95% CI: 0.86, 1.08). In models adjusted for clinical and sociodemographic diabetes risk factors, the association was attenuated among White participants (RR: 1.10; 95% CI: 0.95, 1.28) and remained null among Black participants (RR: 0.90; 95% CI: 0.80, 1.01).

Conclusion

sCD14 was associated with incident diabetes risk in White but not Black adults, but this association was explained by diabetes risk factors.

Cystatin C alleviates unconjugated bilirubin-induced neurotoxicity by promoting bilirubin clearance from neurocytes via exosomes, dependent on hepatocyte UGT1A1 activity

There is an urgent need to identify effective drugs for the treatment of nerve injury caused by unconjugated bilirubin (UCB). Our previous research found that cystatin C (CST3) alleviates UCB-induced neurotoxicity by promoting autophagy in nerve cells, but that autophagy inhibitors did not completely inhibit the effects of CST3. This study investigated whether CST3 could alleviate the neurotoxicity of UCB by promoting the secretion and transport of exosomes containing UCB to the liver for metabolism. It demonstrated that hyperbilirubinemia mice treated with CST3 had a higher number of serum exosomes than those in hyperbilirubinemia mice treated with phosphate-buffered saline. CST3-mediated protection against UCB-induced damage was abolished when autophagy and extracellular vesicle inhibitors were used in combination. The number of exosomes in the CST3 overexpression group was higher than that in the control group. Molecular docking experiments showed that UCB and CST3 had high docking score (-8.2). These results suggest that UCB may be excreted from cells by exosomes, and CST3 may promote this process by binding to UCB and entering the exosomes. We demonstrated that the effect of CST3 relied on liver cells with normal UDP-glucuronyl transferase1A1 (UGT1A1) activity in a coculture system of HT22 and L02 cells. CST3 levels were lower in exosomes secreted by L02 cells than in those secreted by human umbilical vein endothelial cells (HUVECs), whereas CST3 levels were higher in the culture supernatants of L02 cells than in the culture supernatants of HUVECs. This suggests that UCB exosomes in L02 cells may be released and internalized by CST3 and that UCB is then processed by UGT1A1 to conjugate UCB, thus reducing its toxicity. These results suggest that CST3 might alleviate UCB-induced neurotoxicity by promoting the clearance of UCB from cells via exosomes and that these effects are dependent on UGT1A1 activity in liver cells.

Serum CD14 concentration is associated with obesity and insulin resistance in non-diabetic individuals

OBJECTIVE

CD14 is a lipopolysaccharide-binding protein that serves as a marker of monocytes. The role of circulating CD14 in patients with obesity without diabetes remains unknown. Here, we characterized the relationships between serum CD14 concentration and metabolic parameters related to diabetes and obesity.

METHODS

We performed an observational, prospective case-control study. Eighty participants were evaluated: 26 drug-naïve patients with type 2 diabetes mellitus and 54 healthy individuals. We compared the circulating CD14 concentration and metabolic parameters of the participants with and without diabetes.

RESULTS

The circulating CD14 concentration did not significantly differ between the two groups, but was lower in participants with obesity than in lean controls. No significant associations existed between CD14 concentration and metabolic parameters in the participants with diabetes, but in those without diabetes, the circulating CD14 concentration significantly negatively correlated with body mass index; waist circumference; the concentrations of fasting insulin, 2-hour post-load glucose, 2-h post-load insulin, and low-density lipoprotein-cholesterol; homeostasis model of assessment (HOMA) of insulin resistance; and HOMA beta-cell function.

CONCLUSIONS

This is the first study to show associations of serum CD14 concentration with metabolic parameters in non-diabetic individuals. Circulating CD14 may represent a useful biomarker of metabolic dysfunction in non-diabetic individuals.