Diabetic nephropathy (DN) is regarded as the leading cause of end-stage renal disease worldwide and lacks novel therapeutic targets. To screen and verify special biomarkers for glomerular injury in patients with DN, fifteen datasets were retrieved from the Gene Expression Omnibus (GEO) database, correspondingly divided into training and testing cohorts and then merged. Using the limma package, 140 differentially expressed genes (DEGs) were screened out between 81 glomerular DN samples and 41 normal ones from the training cohort. With the help of the ConsensusClusterPlus and WGCNA packages, the 81 glomerular DN samples were distinctly divided into two subclusters, and two highly associated modules were identified. By using machine learning algorithms (LASSO, RF, and SVM-RFE) and the Venn diagram, two overlapping genes (PRKAR2B and TGFBI) were finally determined as potential biomarkers, which were further validated in external testing datasets and the HFD/STZ-induced mouse models. Based on the biomarkers, the diagnostic model was developed with reliable predictive ability for diabetic glomerular injury. Enrichment analyses indicated the apparent abnormal immune status in patients with DN, and the two biomarkers played an important role in the immune microenvironment. The identified biomarkers demonstrated a meaningful correlation between the immune cells’ infiltration and renal function. In conclusion, two robust genes were identified as diagnostic biomarkers and may serve as potential targets for therapeutics of DN, which were closely associated with multiple immune cells.

Background and Objectives. Genome-wide association studies (GWAS) have shown that cartilage intermediate layer protein 2 (CILP2) is associated with blood lipid levels and coronary heart disease (CHD). However, no study has reported whether CILP2 is related to atherosclerosis in humans. The purpose of the current study is to identify the associations between CILP2 and atherosclerosis in vitro and in vivo. Methods and Results. Circulating CILP2 levels (measured by ELISA) were compared to various insulin resistance- and atherosclerosis-related parameters in normal subjects and newly diagnosed CHD patients. THP-1 cells were cultured and treated with indicated stimulators. Western blots and RT-PCR were performed to examine protein and mRNA expressions. The results showed that there were significantly higher circulating CILP2 levels in CHD patients relative to healthy controls. Circulating CILP2 correlated positively with waist-hip ratio (WHR), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), HbA1c, homeostasis model assessment of insulin resistance (HOMA-IR), and Gensini scores. In an in vitro study, we found that CILP2 increased oxidatively modified LDL-stimulated lipid accumulation in THP-1 macrophages via the upregulation of CD36 expression. Inhibition of PPARγ signaling eliminated the CILP2 regulation of CD36 expression in THP-1 macrophages. CILP2 positively regulated CD36 transcription through PPARγ-mediated action on two peroxisome-proliferator-responsive elements (PPREs) binding sites of CD36 promoter, PPRE-G, and PPRE-J. Conclusions. Our findings have uncovered a novel role for CILP2 in lipid uptake and foam cell formation. This role is mediated by CD36 through the activation of PPARγ pathway.

Previous studies on serum fetuin-B (fetuin-like protein IRL685) have investigated its association with T2DM; however, the reason for the variation in serum fetuin-B and its regulatory factors in metabolic disease remain unclear. Here, we evaluated serum fetuin-B levels in women with newly diagnosed MetS and performed multiple interventions to investigate the role of fetuin-B in the pathogenesis of MetS. Serum fetuin-B levels were assessed using ELISA. Bioinformatics analysis was performed to analyze fetuin-B-related genes and signaling pathways. Additionally, oxidative stress parameters were measured in the in vitro study. For subgroup analyses, we performed EHC, OGTT, and treatment with a GLP-1RA to investigate the regulatory factors of serum fetuin-B. We found that in comparison with healthy subjects, serum fetuin-B levels were markedly increased in women with MetS. Further, serum fetuin-B showed a positive correlation with WHR, FAT%, TG, FBG, HbA1c, FIns, HOMA-IR, VAI, and LAP. Bioinformatics analysis revealed that most fetuin-B-related core genes were involved in cholesterol metabolism and fat decomposition. Consistent with this finding, multivariate regression analysis showed that triglyceride content and WHR were independently associated with serum fetuin-B. We also observed that serum fetuin-B levels were markedly elevated in healthy subjects after glucose loading and in women with MetS during EHC. In vitro, overexpression of fetuin-B promoted oxidative stress in HepG2 cell. After 6 months of treatment with a GLP-1RA, serum fetuin-B levels in women with MetS decreased following an improvement in metabolism and insulin sensitivity. Therefore, serum fetuin-B is associated with MetS, which may serve as a biomarker of oxidative stress. This trial is registered with ChiCTR-OCC-11001422.