Glucagon-like peptide-1 receptor (GLP-1R) agonists have emerged as treatment options for type 2 diabetes mellitus (T2DM). Here, we designed a high-throughput GLP-1R extracellular domain (ECD)-based system that enabled the screening of high-potency receptor-biased GLP-1R agonists demonstrating new pharmacological virtues. Firstly, six 12-mer peptides (termed PEP01–06), screened from a large phage displayed peptide library were fused to the N-terminus of Exendin-4 (29–39) to generate PEP07–12. By the use of four lysine-altered PEP07 (PEP13–16) as the starting point, a series of fatty chain conjugates (PEP17–20) were synthesized and evaluated by in vitro GLP-1R-based cell assays. In addition, the acute and long-term in vivo effects on diet-induced obesity (DIO) mice were further evaluated. All four conjugates showed good receptor activation efficacy, and PEP20 was selected to undergo further assessment. Preclinical experiments in DIO mice demonstrated that PEP20 had significant insulinotropic activities and glucose-lowering abilities. Moreover, a prolonged antidiabetic effect of PEP20 was also observed by the hypoglycemic test in DIO mice. Furthermore, long-term treatment with PEP20 achieved beneficial effects on the food intake, weight gain, hemoglobin A1C (HbA1C) lowering activity, and glucose tolerance compared with the control and was similar to the Liraglutide. In conclusion, PEP20, a GLP-1R ECD-biased agonist, may provide a novel therapeutic approach to T2DM.

An association between coronary artery disease (CAD) and serum omentin-1 was recently identified. The aim of the present study was to investigate the effect of atorvastatin on serum levels of omentin-1 in patients with CAD. One-hundred and ninety-eight patients with CAD were divided into two groups: those with acute coronary syndrome (ACS) and those with stable angina pectoris (SAP). All patients were randomized to receive atorvastatin therapy at a dose of either 20 or 40 mg/day for 12 weeks. Serum omentin-1 levels and other parameters were determined at baseline and at the end of the study. Atorvastatin at 20 and 40 mg/day increased serum omentin-1 levels in patients with ACS (20 mg, P=0.007; 40 mg, P<0.001) and in those with SAP (20 mg, P=0.017; 40 mg, P<0.001). Atorvastatin at 40 mg induced greater changes in serum omentin-1 levels compared with 20 mg atorvastatin in both the ACS group (P=0.003) and the SAP group (P=0.012). The increments of serum omentin-1 levels with atorvastatin administration inversely correlated with changes in LDL cholesterol (r=-0.145, P=0.041), interleukin-6 (r=-0.162, P=0.023), and high-sensitivity C-reactive protein (r=-0.185, P=0.009) in patients with CAD. Furthermore, changes in LDL cholesterol (β=-0.158, P=0.027) and interleukin-6 (β=-0.154, P=0.044) remained independent determinants of omentin-1 alterations in standard multiple regression analysis (R=0.122, P=0.006) after adjusting for age, sex, smoking, family history of CAD, and BMI in patients with CAD. Atorvastatin increased serum omentin-1 concentrations in patients with CAD in a dose-dependent manner.

Disulfide bond-reductase (DSBR) exerts an initial role in the enzymatic degradation of feather waste. However, despite its significance, there are currently very few reports on the heterologous expression and enzymatic properties of this type of enzyme. This study focuses on a novel DSBR derived from the strain Stenotrophomonas sp. Yang-5 (Yang-5-DSBR), which was previously found to efficiently degrade feathers. The target band of the DSBR was cloned by PCR, with a size of 687 bp. Domain prediction revealed that the enzyme consists of two distinct parts: N-terminal domain similar to glutathione-S-transferase, spanning amino acids from 1 to 92, and C-terminal domain spanning amino acids from 110 to 204. Subsequently, recombinant expression was carried out using a prokaryotic expression host, followed by nickel column purification of the protein. SDS-PAGE analysis showed that the size of the target protein was approximately 26 kDa, which was in line with our expectations. Enzymatic property assays indicated that the optimal reaction temperature and pH for the Yang-5-DSBR were 35 °C and pH 7.0, respectively. It maintained over 80% enzymatic activity at pH levels ranging from 6.0 to 8.0 and at 40 °C, demonstrating moderate tolerance with significant potential for further improvement. Notably, most metal ions and chemicals inhibited the activity of Yang-5-DSBR, but among them, Al³⁺, Mg²⁺ and Mn²⁺ at a concentration of 0.025 mM could enhance enzymatic activity by 20–50%. Additionally, the presence of 2.5% reducing reagent DTT increased enzymatic activity by 20%, akin to enzymes with Cys as a catalytic key amino acid, such as keratinase and nitrilase. Substrate specificity studies revealed that Yang-5-DSBR had a preference for GSSG and soluble keratin but exhibited lower activity towards other feather substrates. Kinetic parameter assays determined the V_max and K_M of DSBR to be 7.4 and 6.7 mg/mL, respectively. Overall, these insights enhance understanding of DSBR’s role in feather degradation and facilitate its potential applications in biochemical processes and industry.