Serum Soluble Epidermal Growth Factor Receptor Level Increase in Patients Newly Diagnosed with Type 2 Diabetes Mellitus

Increased serum extrachromosomal circular DNA SORBS1circle level is associated with insulin resistance in patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

Extrachromosomal circular DNAs (eccDNAs) exist in human blood and somatic cells, and are essential for oncogene plasticity and drug resistance. However, the presence and impact of eccDNAs in type 2 diabetes mellitus (T2DM) remains inadequately understood.

METHODS

We purified and sequenced the serum eccDNAs obtained from newly diagnosed T2DM patients and normal control (NC) subjects using Circle-sequencing. We validated the level of a novel circulating eccDNA named sorbin and SH3-domain- containing-1circle97206791-97208025 (SORBS1circle) in 106 newly diagnosed T2DM patients. The relationship between eccDNA SORBS1circle and clinical data was analyzed. Furthermore, we explored the source and expression level of eccDNA SORBS1circle in the high glucose and palmitate (HG/PA)-induced hepatocyte (HepG2 cell) insulin resistance model.

RESULTS

A total of 22,543 and 19,195 eccDNAs were found in serum samples obtained from newly diagnosed T2DM patients and NC subjects, respectively. The T2DM patients had a greater distribution of eccDNA on chromosomes 1, 14, 16, 17, 18, 19, 20 and X. Additionally, 598 serum eccDNAs were found to be upregulated, while 856 eccDNAs were downregulated in T2DM patients compared with NC subjects. KEGG analysis demonstrated that the genes carried by eccDNAs were mainly associated with insulin resistance. Moreover, it was validated that the eccDNA SORBS1circle was significantly increased in serum of newly diagnosed T2DM patients (106 T2DM patients vs. 40 NC subjects). The serum eccDNA SORBS1circle content was positively correlated with the levels of glycosylated hemoglobin A1C (HbA1C) and homeostasis model assessment of insulin resistance (HOMA-IR) in T2DM patients. Intracellular eccDNA SORBS1circle expression was significantly enhanced in the high glucose and palmitate (HG/PA)-induced hepatocyte (HepG2 cell) insulin resistance model. Moreover, the upregulation of eccDNA SORBS1circle in the HG/PA-treated HepG2 cells was dependent on generation of apoptotic DNA fragmentation.

CONCLUSIONS

These results provide a preliminary understanding of the circulating eccDNA patterns at the early stage of T2DM and suggest that eccDNA SORBS1circle may be involved in the development of insulin resistance.

A Pilot Genome-Wide Association Study Identifies Novel Markers of Metabolic Syndrome in Patients with Psoriasis

BACKGROUND

Recent studies have reported that psoriasis is associated with the development of metabolic syndrome. Genome-wide association studies have been used to discover gene variant markers that occur frequently in case group in relation to specific diseases.

OBJECTIVE

The aim of the present study was to investigate the variants of specific genes involved in metabolic syndrome associated with psoriasis.

METHODS

A total of 95 psoriasis patients were recruited and divided into two groups: one with metabolic syndrome (38 patients) and the other without (57 patients). After genotyping, imputation, and quality checking, the association between the several single nucleotide polymorphisms and metabolic syndrome in psoriasis was tested, followed by gene set enrichment analysis.

RESULTS

We found 76 gene polymorphisms that conferred an increased risk for metabolic syndrome in patients with psoriasis. Four single nucleotide polymorphisms (rs17154774 of FRMD4A, rs77498336 of GPR116, rs75949580 and rs187682251 of MAPK4) showed the strongest association between metabolic syndrome and psoriasis. The epidermal growth factor receptor protein was located at the center of the protein interactions for the gene polymorphisms.

CONCLUSION

This study identified several previously unknown polymorphisms associated with metabolic syndrome in psoriasis. These results highlight the potential for future genetic studies to elucidate the development, and ultimately prevent the onset, of metabolic syndrome in patients with psoriasis.

Effect of cholesterol-lowering agents on soluble epidermal growth factor receptor level in type 2 diabetes and hypercholesterolemia

Soluble epidermal growth factor receptor (sEGFR) levels are elevated in patients with type 2 diabetes mellitus (T2DM) and positively correlate with blood glucose and cholesterol levels. However, how cholesterol-lowering treatment in patients with T2DM affects the sEGFR level is unknown. Therefore, we investigated the change of serum sEGFR after cholesterol-lowering treatment in type 2 diabetic patients with hypercholesterolemia. This study is a non-randomized, prospective observational study. A total of 115 patients were treated in either the rosuvastatin monotherapy group (R group, 5 mg/day, n = 59) or the rosuvastatin/ezetimibe combination therapy group (RE group, 5 mg/10 mg/day, n = 56) for 12 weeks. We measured serum levels of lipids and sEGFR using an ELISA kit before and after 12 weeks of treatment in each group. The low-density lipoprotein cholesterol (LDL-C) level was significantly reduced (from 130.27 ± 27.09 to 76.24 ± 26.82 mg/dL; P < .001) after 12 weeks of treatment and more so in the RE group than in the R group (from 131.68 ± 28.72 to 87.13 ± 27.04 mg/dL, P < .001 in the R group; from 128.78 ± 25.58 to 64.75 ± 21.52 mg/dL, P < .001 in the RE group; R vs RE group, P < .001). The sEGFR level was significantly decreased after 12 weeks of treatment (from 50.34 ± 13.31 to 45.75 ± 11.54 ng/mL; P = .007). The RE group only showed a significant reduction in the sEGFR level after treatment (from 50.94 ± 12.10 to 44.80 ± 11.36 ng/mL; P = .007). Moreover, the sEGFR level was significantly reduced only when the LDL-C level was significantly reduced (from 50.46 ± 10.66 to 46.24 ± 11.86 ng/mL; P = .043). The serum sEGFR level was significantly reduced by cholesterol-lowering treatment with rosuvastatin alone or rosuvastatin/ezetimibe. We suggested that sEGFR may play a significant role in insulin resistance (IR) and inflammation, which are central pathophysiological mechanisms. We confirmed the possibility of using sEGFR as a biomarker to predict a good response to lipid-lowering treatment in type 2 diabetes patients with hypercholesterolemia.

Soluble LRIG2 is a potential biomarker for type 2 diabetes mellitus

Background

Early diagnosis and treatment of type 2 diabetes can delay the onset of microvascular and macrovascular complications. Therefore, the identification of a novel biomarker for diagnosing diabetes is necessary. In the present study, the role of serum soluble leucine-rich repeats and immunoglobulin like domains 2 (sLRIG2) was investigated as a diagnostic biomarker of type 2 diabetes.

Methods

A total of 240 subjects with newly diagnosed type 2 diabetes (n=80), prediabetes (n=80), or normal glucose tolerance (NGT; n=80) were included in this study. The fasting serum sLRIG2 level was measured using a quantitative sandwich enzyme immunoassay technique with an enzyme-linked immunosorbent assay (ELISA). Serum sLRIG2 levels were compared among the three groups, and the associations of serum sLRIG2 levels with clinical variables were investigated.

Results

Serum sLRIG2 levels were significantly higher in subjects with type 2 diabetes (16.7±8.0 ng/mL) than in subjects without diabetes (NGT group: 12.3±5.3 ng/mL, P<0.001; prediabetes group: 13.2±5.8 ng/mL, P=0.002). Glycosylated hemoglobin (HbA1c: r=0.378, P<0.001) and blood glucose (fasting: r=0.421, P<0.001; 2-hour postprandial: r=0.433, P<0.001) correlated more strongly with sLRIG2 than any other clinical variables.

Conclusions

The serum sLRIG2 levels correlated with glucose parameters; thus, sLRIG2 might be a novel diagnostic biomarker for type 2 diabetes.

Soluble EGFR, a hepatokine, and adipsin, an adipokine, are biomarkers correlated with distinct aspects of insulin resistance in type 2 diabetes subjects

BACKGROUND

Insulin resistance can occur in all metabolic organs including the liver, adipose tissue, and skeletal muscles. Circulating soluble epidermal growth factor receptor (soluble EGFR) and adipsin levels are altered in obese diabetic mice and are possibly correlated with insulin resistance in both mice and humans. Here, we investigated the significance of soluble EGFR and adipsin as biomarkers for insulin resistance in Japanese subjects with type 2 diabetes.

METHODS

We measured the soluble EGFR and adipsin levels in sera from 47 non-diabetic subjects and 106 subjects with type 2 diabetes using enzyme-linked immunosorbent assays (ELISAs) and analyzed the correlations between the soluble EGFR or adipsin levels and metabolic parameters in type 2 diabetes subjects. We also measured the gene expression levels of Egfr and Cfd (adipsin) in the liver, adipose tissue, and skeletal muscle in mice with/without obesity or diabetes.

RESULTS

The soluble EGFR levels were correlated with the fasting blood glucose level (P = 0.010), HOMA-IR (P = 0.035), HbA1c level (P = 0.007), HDL-cholesterol level (P = 0.044), and FIB-4 index (P = 0.017) after adjustments for age, sex, and total cholesterol levels. These factors are known to be related to hepatic insulin resistance. The serum adipsin levels were correlated with BMI (P < 0.001), waist circumference (P < 0.001), fasting serum insulin level (P = 0.001), HOMA-IR (P = 0.009), CPR-index (P = 0.045), and FIB-4 index (P = 0.007) after adjustments for age, sex and eGFR levels. Abdominal adiposity leads to the potentiation of these factors. The expression of Egfr was abundant in the liver, while Cfd was predominantly expressed in adipose tissue in mice.

CONCLUSIONS

Soluble EGFR, a hepatokine, is correlated with insulin resistance in the liver, while adipsin, an adipokine, is associated with adipose insulin resistance.Trial registration: UMIN Clinical Trials Registry (www.umin.ac.jp), UMIN000020474. Registered 8 January 2016.

Epidermal growth factor protects against myocardial ischaemia reperfusion injury through activating Nrf2 signalling pathway

Alleviating the oxidant stress associated with myocardial ischaemia reperfusion has been demonstrated as a potential therapeutic approach to limit ischaemia reperfusion (I/R)-induced cardiac damage. It is reported that EGFR/erbB2 signalling is an important cardiac survival pathway in cardiac function and activation of EGFR has a cardiovascular effect in global ischaemia. Epidermal growth factor (EGF), a typical EGFR ligand, was considered to have a significant role in activating EGFR. However, no evidence has been published whether exogenous EGF has protective effects on myocardial ischaemia reperfusion. This study aims to investigate the effects of EGF in I/R-induced heart injury and to demonstrate its mechanisms. H9c2 cells challenged with H₂O₂ were used for in vitro biological activity and mechanistic studies. The malondialdehyde (MDA) and Superoxide Dismutase (SOD) levels in H9c2 cells were determined, and the cell viability was assessed by MTT assay. Myocardial I/R mouse administrated with or without EGF were used for in vivo studies. Pretreatment of H9c2 cells with EGF activated Nrf2 signalling pathway, attenuated H₂O₂-increased MDA and H₂O₂-reduced SOD level, followed by the inhibition of H₂O₂-induced cell death. In in vivo animal models of myocardial I/R, administration of EGF reduced infarct size and myocardial apoptosis. These data support that EGF decreases oxidative stress and attenuates myocardial ischaemia reperfusion injury via activating Nrf2.