Bisphenol-A Abrogates Proliferation and Differentiation of C2C12 Mouse Myoblasts via Downregulation of Phospho-P65 NF-κB Signaling Pathway.

Previous studies showed that bisphenol-A (BPA), a monomer of polycarbonate plastic, is leached out and contaminated in foods and beverages. This study aimed to investigate the effects of BPA on the myogenesis of adult muscle stem cells. C2C12 myoblasts were treated with BPA in both proliferation and differentiation conditions. Cytotoxicity, cell proliferation and differentiation, antioxidant activity, apoptosis, myogenic regulatory factors (MRFs) gene expression, and mechanism of BPA on myogenesis were examined. C2C12 myoblasts exposed to 25-50 µM BPA showed abnormal morphology, expressing numerous and long cytoplasmic extensions. Cell proliferation was inhibited and was accumulated in subG1 and S phases of the cell cycle, subsequently leading to apoptosis confirmed by nuclear condensation and the expression of apoptosis markers, cleaved caspase-9 and caspase-3. In addition, the activity of antioxidant enzymes, catalase, superoxide dismutase, and glutathione peroxidase was significantly decreased. Meanwhile, BPA suppressed myoblast differentiation by decreasing the number and size of multinucleated myotubes via the modulation of MRF gene expression. Moreover, BPA significantly inhibited the phosphorylation of P65 NF-κB in both proliferation and differentiation conditions. Altogether, the results revealed the adverse effects of BPA on myogenesis leading to abnormal growth and development via the inhibition of phospho-P65 NF-κB.

Stress-induced changes in cognitive function and intestinal barrier integrity can be ameliorated by venlafaxine and synbiotic supplementations.

Stress profoundly impacts various aspects of both physical and psychological well-being. Our previous study demonstrated that venlafaxine (Vlx) and synbiotic (Syn) treatment attenuated learned fear-like behavior and recognition memory impairment in immobilized-stressed rats. In this study, we further investigated the physical, behavior, and cellular mechanisms underlying the effects of Syn and/or Vlx treatment on brain and intestinal functions in stressed rats. Adult male Wistar rats, aged 8 weeks old were subjected to 14 days of immobilization stress showed a decrease in body weight gain and food intake as well as an increase in water consumption, urinary corticosterone levels, and adrenal gland weight. Supplementation of Syn and/or Vlx in stressed rats resulted in mitigation of weight loss, restoration of normal food and fluid intake, and normalization of corticosterone levels. Behavioral analysis showed that treatment with Syn and/or Vlx enhanced depressive-like behaviors and improved spatial learning-memory impairment in stressed rats. Hippocampal dentate gyrus showed stress-induced neuronal cell death, which was attenuated by Syn and/or Vlx treatment. Stress-induced ileum inflammation and increased intestinal permeability were both effectively reduced by the supplementation of Syn. In addition, Syn and Vlx partly contributed to affecting the expression of the glial cell-derived neurotrophic factor in the hippocampus and intestines of stressed rats, suggesting particularly protective effects on both the gut barrier and the brain. This study highlights the intricate interplay between stress physiological responses in the brain and gut. Syn intervention alleviate stress-induced neuronal cell death and modulate depression- and memory impairment-like behaviors, and improve stress-induced gut barrier dysfunction which were similar to those of Vlx. These findings enhance our understanding of stress-related health conditions and suggest the synbiotic intervention may be a promising approach to ameliorate deleterious effects of stress on the gut-brain axis.

A novel model of adenine-induced chronic kidney disease-associated gastrointestinal dysfunction in mice: The gut-kidney axis.

Although constipation is a common complication of chronic kidney disease (CKD), there is no animal model that can be used to study the association between renal impairment and gastrointestinal function without interfering with the gastrointestinal tract of the model. Therefore, we determined whether adenine could induce CKD in association with gastrointestinal dysfunction. Six-week-old ICR mice were intraperitoneally injected with saline, 25, 50, or 75 mg adenine/kg body weight for 21 days. Blood urea nitrogen (BUN), plasma creatinine, and renal histopathology were evaluated. Defecation status was evaluated from defecation frequency and fecal water content. Colonic smooth muscle contraction was measured by the organ bath technique, and transepithelial electrical resistance (TEER) was measured using an Ussing chamber. In the 50 mg/kg treatment group, BUN and creatinine were significantly increased compared with control, and inflammatory cell infiltration, glomerular necrosis, tubular dilatation, and interstitial fibrosis were observed in renal tissues. Mice in this group also showed a significant decrease in defecation frequency, fecal water content, colonic motility index, and TEER. Overall, 50 mg/kg of adenine was the best dose to induce CKD with associated constipation and intestinal barrier impairment. Therefore, this adenine administration model can be recommended for CKD-associated gastrointestinal dysfunction research.

Sargassum plagiophyllum Extract Enhances Colonic Functions and Modulates Gut Microbiota in Constipated Mice.

Constipation is a symptom that is widely found in the world's population. Various dietary supplementations are used to relieve and prevent constipation. Seaweed is widely used for its health benefits. In this study, we aimed to investigate the effects of Sargassum plagiophyllum extract (SPE) on functions of the gastrointestinal tract and gut microbiota. The results show that SPE pretreatment increased the frequency of gut contraction, leading to reduce gut transit time. SPE pretreatment also significantly increased the secretion of Cl− and reduced Na+ absorption, increasing fecal water content in constipated mice (p < 0.05). In addition, the Bifidobacteria population in cecal contents was significantly higher in constipated mice pretreated with 500 mg/kg SPE for 14 days than in untreated constipated mice (p < 0.05). Our findings suggest that SPE can prevent constipation in loperamide-induced mice. This study may be useful for the development of human food supplements from S. plagiophyllum, which prevent constipation.

Styrene Oxide Caused Cell Cycle Arrest and Abolished Myogenic Differentiation of C2C12 Myoblasts.

Contaminations of chemicals in foods and drinks are raising public concerns. Among these, styrene, a monomer for plastic production, receives increasing interest due to its ability to leach from the packaging and contaminate in foods and drinks causing many health problems. The present study was designed to investigate the effects of styrene monomer (STR) and its metabolite styrene oxide (STO) on C2C12 myoblast proliferation and differentiation. Based on an MTT assay, both STR and STO showed no cytotoxic effect at 10-100 µM. However, at 50-100 µM STO, but not STR, significantly inhibited cell proliferation. The STO-treated cells were accumulated in S-phase of cell cycles as revealed by flow cytometry. The antioxidant enzyme (catalase and superoxide dismutase) activities and the gene expressing these enzymes of the arrested cells were decreased and ultimately led to nuclear condensation and expression of apoptotic markers such as cleaved caspase-3 and-9, but not cleaved caspase-8. In addition, STO significantly suppressed myogenic differentiation by decreasing both the number and size of differentiated myotubes. Biochemical analysis showed attenuations of total protein synthesis and myosin heavy chain (MHC) protein expression. In conclusion, a metabolite of styrene, STO, leached from plastic packaging of foods and beverages suppressed both myoblast proliferation and differentiation, which would affect skeletal muscle development and regeneration.

Diarylheptanoid 1-(4-hydroxyphenyl)-7-phenyl-(6E)-6-hepten-3-one enhances C2C12 myoblast differentiation by targeting membrane estrogen receptors and activates Akt-mTOR and p38 MAPK-NF-κB signaling axes.

Diarylheptanoid, 1-(4-hydroxyphenyl)-7-phenyl(6E)-6-hepten-3-one (HPPH), has been reported to enhance myoblast differentiation via estrogen receptor (ER). However, the underlying signaling pathway promising this action remains unknown. The present study thus aimed to investigate the signaling pathway of HPPH that enhances myoblast differentiation. Confluence C2C12 myoblasts were induced to differentiate in the absence or presence of HPPH (10 nM). Differentiation markers (myosin heavy chain (MHC) and myogenin) and other signaling molecules implicated in myogenic differentiation were analyzed by immunostaining and western blotting methods. To identify the location of ER and the signaling molecules, specific inhibitors were applied targeting these molecules. Nuclear factor-κB (NF-κB) DNA binding activity was measured using the electrophoresis mobility shift assay. The results showed that HPPH enhanced myoblast differentiation by increasing MHC and myogenin levels, number, and size as well as the fusion index of myotubes. These actions occurred via membrane ER. Several MAPK proteins were activated at the early stage of differentiation. However, only Akt and p38 MAPK, but not ERK, were implicated in these effects. The underlying signaling molecules of Akt to enhance myogenic differentiation by HPPH, at least in part, were mTOR/P70S6K and GSK-3ß. On the other hand, the downstream signaling molecule of p38 MAPK was NF-κB. Our results suggested that HPPH enhanced myogenic differentiation by binding with membrane ER, which in turn recruited multiple axes including Akt-mTOR-P70S6K, Akt-GSK-3ß, and p38 MAPK-NF-κB.

Prebiotic oligosaccharides from dragon fruits alter gut motility in mice.

Dragon fruit oligosaccharide (DFO) has a prebiotic property which improves gut health by selectively stimulating the colonic microbiota. Altering microbiota composition may affect intestinal motility. However, no study has been done to understand the DFO effects on gut motor functions. This research thus aimed to investigate the DFO effects on mice colons compared to the prebiotic fructo-oligosaccharide (FOS) and probiotic bifidobacteria. The mice in this study received distilled water; 100, 500, and 1000 mg/kg DFO; 1000 mg/kg FOS; or 109 CFU Bifidobacterium animalis daily for 1 week and some treatments for 2 weeks. Gastrointestinal transits were analysed and motility patterns, smooth muscle (SM) contractions and morphological structures of the colons were assessed. Administration of FOS, 500 and 1000 mg/kg DFO significantly increased fecal output when compared to the control group. In mice treated with FOS and bifidobacteria, gut transit time was reduced, while upper gut transit was increased in comparison to DFO groups. Spatiotemporal maps of colonic wall motions showed that DFO increased the number of colonic non-propagation contractions and fecal pellet velocity, consistent with the results from groups treated with FOS and bifidobacteria. DFO also increased the amplitude and duration of colonic SM contractions. Histological stains showed normal epithelia, crypts, goblet cells, and SM thickness in all groups. In conclusion, DFO increased colonic SM contractions without morphological change and acted as a bulk-forming and stimulant laxative to increase fecal output and intestinal motility. Thus, DFO as a dietary supplement may promote gut health and correct gastrointestinal motility disorders.

Molecular cloning and distribution of oxytocin/vasopressin-like mRNA in the blue swimming crab, Portunus pelagicus, and its inhibitory effect on ovarian steroid release.

This study was aimed to characterize the full length of mRNA of oxytocin/vasopressin (OT/VP)-like mRNA in female Portunus pelagicus (PpelOT/VP-like mRNA) using a partial PpelOT/VP-like sequence obtained previously in our transcriptome analysis (Saetan, 2014) to construct the primers. The PpelOT/VP-like mRNA was 626 bp long and it encoded the preprohormones containing 158 amino acids. This preprohormone consisted of a signal peptide, an active nonapeptide (CFITNCPPG) followed by the dibasic cleavage site (GKR), and the neurophysin domain. Sequence alignment of the PpelOT/VP-like peptide with those of other animals revealed strong molecular conservation. Phylogenetic analysis of encoded proteins revealed that the PpelOT/VP-like peptide was clustered within the group of crustacean OT/VP-like peptide. Analysis by RT-PCR revealed the expression of mRNA transcripts in the eyestalk, brain, ventral nerve cord (VNC), ovary, intestine and gill. The in situ hybridization demonstrated the cellular localizations of the transcripts in the central nervous system (CNS) and ovary tissues. In the eyestalk, the mRNA expression was observed in the neuronal clusters 1-5 but not in the sinus gland complex. In the brain and the VNC, the transcripts were detected in all neuronal clusters but not in the glial cell. In the ovary, the transcripts were found in all stages of oocytes (Oc1, Oc2, Oc3, and Oc4). In addition, synthetic PpelOT/VP-like peptide could inhibit steroid release from the ovary. The knowledge gained from this study will provide more understanding on neuro-endocrinological controls in this crab species.