Background: Intestinal smooth muscle cells (SMCs) undergo substantial morphological, phenotypic, and contractile changes during inflammatory bowel disease (IBD). SMCs act as a source and target for different inflammatory mediators, however their role in IBD pathogenesis is usually overlooked. Glucagon-like peptide-1 (GLP-1) is an incretin hormone reported to exert multiple anti-inflammatory effects in different tissues including the gastrointestinal tract through various mechanisms. Aim: The aim of this research is to explore the effect of GLP-1 analog exendin-4 on the expression and secretion of inflammatory markers from mouse colon smooth muscle cells (CSMCs) after stimulation with lipopolysaccharide (LPS). Materials and methods: Freshly isolated CSMCs from male BALB/c mice were cultured in DMEM and treated with vehicle, LPS (1 µg/mL), LPS+exendin-4 (50 nM), or LPS+exendin-4 (100 nM) for 24 h. Expression of inflammatory cytokines was then evaluated by antibody array membrane. Results: CSMCs showed basal expression of several cytokines which was enhanced with the induction of inflammation by LPS. However, exendin-4 (50 and 100 nM) significantly (p<0.05) reduced the expression of multiple cytokines including tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), T cell activation gene-3 (TCA-3), stromal cell-derived factor-1 (SDF-1), and macrophage colony stimulating factor (M-CSF). To confirm these results, expression of these cytokines was further assessed by enzyme-linked immunosorbent assay and real-time polymerase chain reaction and similar results were also observed. Moreover, secretion of TNF-α and IL1-α into the conditioned media was significantly downregulated by exendin-4 when compared to LPS-treated cells. Furthermore, LPS increased NF-κB phosphorylation, while exendin-4 significantly reduced levels of NF-κB phosphorylation. Conclusion: These data indicate that GLP-1 analogs can exert significant anti-inflammatory effects on CSMCs and can potentially be used as an adjunct treatment for inflammatory bowel conditions.

Malic Enzyme 1 (ME1) supports lipogenesis, cholesterol synthesis, and cellular redox potential by catalyzing the decarboxylation of L-malate to pyruvate, and the concomitant reduction of NADP to NADPH. We examined the contribution of ME1 to the development of obesity by provision of an obesogenic diet to C57BL/6 wild type (WT) and MOD-1 (lack ME1 protein) female mice. Adiposity, serum hormone levels, and adipose, mammary gland, liver, and small intestine gene expression patterns were compared between experimental groups after 10 weeks on a diet. Relative to WT female mice, MOD-1 female mice exhibited lower body weights and less adiposity; decreased concentrations of insulin, leptin, and estrogen; higher concentrations of adiponectin and progesterone; smaller-sized mammary gland adipocytes; and reduced hepatosteatosis. MOD-1 mice had diminished expression of Lep gene in abdominal fat; Lep, Pparg, Klf9, and Acaca genes in mammary glands; Pparg and Cdkn1a genes in liver; and Tlr9 and Ffar3 genes in the small intestine. By contrast, liver expression of Cdkn2a and Lepr genes was augmented in MOD-1, relative to WT mice. Results document an integrative role for ME1 in development of female obesity, suggest novel linkages with specific pathways/genes, and further support the therapeutic targeting of ME1 for obesity, diabetes, and fatty liver disease.

Polycystic ovarian syndrome (PCOS) is a prevalent endocrinopathy among women of a reproductive age. Although not included in the diagnostic criteria, insulin resistance (IR) is a major characteristic of PCOS and may contribute to its development. The exact cause of IR remains unknown but appears to be multifactorial. Changes in the levels of leptin, adiponectin, branched‑chain amino acids (BCAAs) and/or homocysteine have been reported in women with PCOS. However, the relative contribution of the aforementioned metabolites to PCOS has not been tested in Jordan. In the present study, 154 women diagnosed with PCOS and 151 normally menstruating women matched by age and body mass index (BMI) were recruited. The levels of leptin, adiponectin, BCAAs, homocysteine and 5‑methyltetrahydrofolate (5‑MTHF) were measured in the serum of the recruited participants. It was revealed that homocysteine levels were significantly elevated in women with PCOS compared with normally menstruating women (P<0.0001), while 5‑MTHF (P=0.024), leptin (P=0.027) and adiponectin (P=0.010) levels were significantly lower. In multivariate analysis, serum homocysteine had the strongest association with PCOS and significantly increased its risk [P<0.0001; odds ratio 1.217; 95% confidence interval (CI) 1.157‑1.280]. With an area under the curve of 0.855 (95% CI 0.811‑0.898) in receiver operating characteristic analysis, serum homocysteine was determined to be a good predictor for PCOS diagnosis based on Rotterdam guidelines. It was concluded that serum levels of homocysteine are elevated in women with PCOS in Jordan independent of age, BMI, or leptin, adiponectin and BCAAs levels.

Inflammatory bowel disease (IBD) is a chronic incurable condition characterized by relapsing inflammation of the gut. Intestinal smooth muscle cells (SMCs) are affected structurally and functionally during IBD due to excessive production of different inflammatory mediators. Metformin is a widely used antidiabetic agent known to exert several anti‑inflammatory effects in different tissues independently from its hypoglycemic effect. The aim of the present study was to investigate the effect of metformin on expression and secretion of different cytokines and chemokines from mouse colon SMCs (CSMCs) following induction of inflammation with lipopolysaccharide (LPS) in vitro. CSMCs from male BALB/c mice were isolated and cultured in Dulbecco's modified Eagle's medium and treated with LPS (1 µg/ml) and 0, 5, 10 or 20 mM metformin for 24 h. Expression and secretion of tumor necrosis factor‑α (TNF‑α), interleukin‑1α (IL‑1α), macrophage colony stimulating factor (M‑CSF), T cell activation gene‑3 (TCA‑3) and stromal cell‑derived factor‑1 (SDF‑1) was evaluated by ELISA. LPS‑treated CSMCs demonstrated significantly increased expression of TNF‑α, IL‑1α, M‑CSF, TCA‑3 and SDF‑1 when compared with the control group (P<0.05). Co‑treatment with metformin (5 and 10 mM) significantly reduced their expression by ~20‑40% when compared with LPS treatment alone (P<0.05). Furthermore, secretion of TNF‑α, IL‑1α, M‑CSF and TCA‑3 into the conditioned media was significantly decreased by metformin (5 and 10 mM; P<0.05). In addition, metformin decreased levels of LPS‑induced nuclear factor‑κB phosphorylation. These data suggest that metformin may provide beneficial anti‑inflammatory effects on CSMCs and it may be utilized as an adjunct therapy for patients suffering from IBD.

Oxytocin produces an excitatory effect on gastric muscle through the activation of receptors present on stomach smooth muscle cells. However, the intracellular mechanisms that mediate oxytocin excitatory effects are still largely unknown. Therefore, we aimed to investigate the signaling pathways involved in oxytocin-induced contractions in gastric smooth muscle, shedding light on phospholipase C (PLC)-β1 signaling and its downstream molecules, including inositol 1,4,5- trisphosphate (IP₃) and myosin light chain kinase (MLCK). The contractions of gastric smooth muscle from male rats were measured in an organ bath set up in response to exogenous oxytocin 10⁻⁷ M, in the presence and absence of inhibitors of the indicated signaling molecules. Oxytocin (10⁻⁹–10⁻⁵ M) induced dose-dependent stomach smooth muscle contraction. Pre-incubation with atosiban, an oxytocin receptor inhibitor, abolished the oxytocin-induced contraction. Moreover, PLC β1 inhibitor (U73122) and IP₃ inhibitor Xestospongin C inhibited oxytocin-induced muscle contraction to various degrees. Verapamil, a calcium channel blocker, inhibited oxytocin-induced contraction, and pre-incubation of the strips, with both verapamil and Xestospongin C, further inhibited the excitatory effect of oxytocin. Chelation of intracellular calcium with BAPT-AM (1,2-bis-(o-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid) significantly inhibited the effect of oxytocin on muscle contraction. Finally, pre-incubation of the strips with the Ca²⁺/calmodulin-dependent protein kinase selective inhibitor STO-609 significantly inhibited the contraction induced by oxytocin. These results suggest that oxytocin directly stimulates its cell surface receptor to activate PLC β1, which in turn liberates IP₃, which eventually elevates intracellular calcium, the prerequisite for smooth muscle contraction.

Background and Objectives: Vitamin D is involved in pancreatic beta-cell function, insulin sensitivity, and inflammation. Further, elevation in branched-chain amino acids (BCAAs) has been implicated in type 2 diabetes (T2DM) pathology. However, the relationship between vitamin D and BCAAs in T2DM remains unclear. The current study aimed to investigate the relationship between vitamin D and BCAAs in T2DM. Materials and Methods: In total, 230 participants (137 with T2DM and 93 healthy controls) were recruited in a cross-sectional study. Furthermore, an additional follow-up study was performed, including 20 T2DM patients with vitamin D deficiency. These patients were prescribed weekly vitamin D tablets (50,000 IU) for three months. The levels of several biochemical parameters were examined at the end of the vitamin D supplementation. Results: The results showed that patients with T2DM had higher serum levels of BCAAs and lower serum levels of 25-hydroxyvitamin D (25(OH)D) compared with those of the healthy controls (p < 0.01). The serum levels of vitamin D were negatively correlated with BCAA levels in T2DM patients (r = −0.1731, p < 0.05). In the follow-up study, 25(OH)D levels were significantly improved (p < 0.001) following vitamin D supplementation. Vitamin D supplementation significantly reduced the levels of BCAAs, HbA1c, total cholesterol, triglycerides, and fasting glucose (p < 0.01). Conclusion: Overall, these results suggest a role for BCAAs and vitamin D in the etiology and progression of T2DM. Thus, managing vitamin D deficiency in patients with T2DM may improve glycemic control and lower BCAA levels.