Chlorogenic Acid Functions as a Novel Agonist of PPARγ2 during the Differentiation of Mouse 3T3-L1 Preadipocytes.

Rosiglitazone (RG) is a well-known activator of peroxisome proliferator-activated receptor-gamma (PPARγ) and used to treat hyperglycemia and type 2 diabetes; however, its clinical application has been confounded by adverse side effects. Here, we assessed the roles of chlorogenic acid (CGA), a phenolic secondary metabolite found in many fruits and vegetables, on the differentiation and lipolysis of mouse 3T3-L1 preadipocytes. The results showed that CGA promoted differentiation in vitro according to oil red O staining and quantitative polymerase chain reaction assays. As a potential molecular mechanism, CGA downregulated mRNA levels of the adipocyte differentiation-inhibitor gene Pref1 and upregulated those of major adipogenic transcriptional factors (Cebpb and Srebp1). Additionally, CGA upregulated the expression of the differentiation-related transcriptional factor PPARγ2 at both the mRNA and protein levels. However, following CGA intervention, the accumulation of intracellular triacylglycerides following preadipocyte differentiation was significantly lower than that in the RG group. Consistent with this, our data indicated that CGA treatment significantly upregulated the expression of lipogenic pathway-related genes Plin and Srebp1 during the differentiation stage, although the influence of CGA was weaker than that of RG. Notably, CGA upregulated the expression of the lipolysis-related gene Hsl, whereas it did not increase the expression of the lipid synthesis-related gene Dgat1. These results demonstrated that CGA might function as a potential PPARγ agonist similar to RG; however, the impact of CGA on lipolysis in 3T3-L1 preadipocytes differed from that of RG.

Inferring the Skeletal Muscle Developmental Changes of Grazing and Barn-Fed Goats from Gene Expression Data.

Thirty-six Xiangdong black goats were used to investigate age-related mRNA and protein expression levels of some genes related to skeletal muscle structural proteins, MRFs and MEF2 family, and skeletal muscle fiber type and composition during skeletal muscle growth under grazing (G) and barn-fed (BF) feeding systems. Goats were slaughtered at six time points selected to reflect developmental changes of skeletal muscle during nonrumination (days 0, 7, and 14), transition (day 42), and rumination phases (days 56 and 70). It was observed that the number of type IIx in the longissimus dorsi was increased quickly while numbers of type IIa and IIb decreased slightly, indicating that these genes were coordinated during the rapid growth and development stages of skeletal muscle. No gene expression was affected (P > 0.05) by feeding system except Myf5 and Myf6. Protein expressions of MYOZ3 and MEF2C were affected (P < 0.05) by age, whereas PGC-1α was linearly decreased in the G group, and only MYOZ3 protein was affected (P < 0.001) by feeding system. Moreover, it was found that PGC-1α and MEF2C proteins may interact with each other in promoting muscle growth. The current results indicate that (1) skeletal muscle growth during days 0-70 after birth is mainly myofiber hypertrophy and differentiation, (2) weaning affects the expression of relevant genes of skeletal muscle structural proteins, skeletal muscle growth, and skeletal muscle fiber type and composition, and (3) nutrition or feeding regimen mainly influences the expression of skeletal muscle growth genes.

Cloning, Phylogenetic Analysis, and Distribution of Free Fatty Acid Receptor GPR120 Expression along the Gastrointestinal Tract of Housing versus Grazing Kid Goats.

G-protein-coupled receptor 120 (GPR120) is reported as a long-chain fatty acid (LCFA) receptor that elicits free fatty acid (FFA) regulation on metabolism homeostasis. The study aimed to clone the gpr120 gene of goats (g-GPR120) and subsequently investigate phylogenetic analysis and tissue distribution throughout the digestive tracts of kid goats, as well as the effect of housing versus grazing (H vs G) feeding systems on GPR120 expression. Partial coding sequence (CDS) of g-GPR120 was cloned and submitted to NCBI (accession no. KU161270 ). Phylogenetic analysis revealed that g-GPR120 shared higher homology in both mRNA and amino acid sequences for ruminants than nonruminants. Immunochemistry, real-time PCR, and Western blot analysis showed that g-GPR120 was expressed throughout the digestive tracts of goats. The expression of g-GPR120 was affected by feeding system and age, with greater expression of g-GPR120 in the G group. It was concluded that the g-GPR120-mediated LCFA chemosensing mechanism is widely present in the tongue and gastrointestinal tract of goats and that its expression can be affected by feeding system and age.

Magnolol and honokiol regulate the calcium-activated potassium channels signaling pathway in Enterotoxigenic Escherichia coli-induced diarrhea mice.

To explore the regulatory mechanisms of magnolol and honokiol on calcium-activated potassium channels signaling pathway in Enterotoxigenic Escherichia coli (ETEC)-induced diarrhea mice, the concentrations of serum chloride ion (Cl(-)), sodium ion (Na(+)), potassium ion (K(+)) and calcium ion (Ca(2+)) were measured. Additionally, the mRNA expressions of calmodulin 1 (CaM), calcium/calmodulin-dependent protein kinase II alpha subunit (CaMKIIα) and beta subunit (CaMKIIß), ryanodine receptor 1, inositol 1,4,5-trisphosphate receptors (IP3 receptors), protein kinases C (PKC), potassium intermediate/small conductance calcium-activated channels (SK) and potassium large conductance calcium-activated channels(BK)were determined. A diarrhea mouse model was established using ETEC suspensions (3.29×10(9)CFU/ml) at a dosage of 0.02ml/g live body weight (BW). Magnolol or honokiol was intragastrically administered at dosages of 100 (M100 or H100), 300 (M300 or H300) and 500 (M500 or H500) mg/kg BW according to a 3×3 factorial arrangement. Magnolol and honokiol increased the Cl(-) and K(+) concentrations, further, upregulated the CaM, BKα1 and BKß3 mRNA levels but downregulated the IP3 receptors 1, PKC, SK1, SK2, SK3, SK4 and BKß4 mRNA expressions. Magnolol and honokiol did not alter the CaMKIIα, CaMKIIß, ryanodine receptor 1, IP3 receptor 2, IP3 receptor 3, BKß1 and BKß2 mRNA expressions. These results clarify that magnolol and honokiol, acting through Ca(2+) channel blockade, inhibit the activation of IP3 receptor 1 to regulate the IP3-Ca(2+) store release, activate CaM to inhibit SK channels, and effectively suppress PKC kinases to promote BKα1 and BKß3 channels opening and BKß4 channel closing, which modulates the intestinal ion secretion.

A mathematical model to describe the diurnal pattern of enteric methane emissions from non-lactating dairy cows post-feeding.

Enteric methane emission is not only a source of energy loss in ruminants, but also a potent contributor to greenhouse gas production. To identify the nature and timing of interventions to reduce methane emissions requires knowledge of temporal kinetics of methane emissions during animal husbandry. Accordingly, a mathematical model was developed to investigate the pattern of enteric methane emissions after feeding in dairy cows. The model facilitated estimation of total enteric methane emissions (V, g) produced by the residual substrate (V1, g) and newly ingested feed (V2, g). The model was fitted to the 10 h methane emission patterns after morning feeding of 16 non-lactating dairy cows with various body weights (BW), and the obtained parameters were used to predict the kinetics of 24 h methane emission for each animal. The rate of methane emission (g/h) reached a maximum within 1 to 2 h after feeding, followed by a gradual post-prandial decline to a basal value before the next feeding. The model satisfactorily fitted curves for each cow according to the criterion of goodness-of-fit, and provided biological descriptions for fluctuations in methane emissions based on basal V1 and feeding V2 in response to the changes in BW and dry matter intake (DMI) of different dairy cows. The basal V1 and feeding V2 are probably maintained by slow- and readily-degradable substrates, respectively. The former contributed at least 0.6 of methane production. In summary, the model provides a means to separate basal V1 and feeding V2 within V, and can be used to predict 24 h emission from a single feeding period.

Alteration of antioxidant enzymes and associated genes induced by grape seed extracts in the primary muscle cells of goats in vitro.

This study was conducted to investigate how the activity and expression of certain paramount antioxidant enzymes respond to grape seed extract (GSE) addition in primary muscle cells of goats. Gluteal primary muscle cells (PMCs) isolated from a 3-week old goat were cultivated as an unstressed cell model, or they were exposed to 100 µM H2O2 to establish a H2O2-stimulated cell model. The activities of catalase (CAT), superoxide dismutases (SOD) and glutathione peroxidases (GPx) in combination with other relevant antioxidant indexes [i.e., reduced glutathione (GSH) and total antioxidant capacity (TAOC)] in response to GSE addition were tested in the unstressed and H2O2-stimulated cell models, and the relative mRNA levels of the CAT, GuZu-SOD, and GPx-1 genes were measured by qPCR. In unstressed PMCs, GSE addition at the dose of 10 µg/ml strikingly attenuated the expression levels of CAT and CuZn-SOD as well as the corresponding enzyme activities. By contrast, in cells pretreated with 100 µM H2O2, the expression and activity levels of these two antioxidant enzymes were enhanced by GSE addition at 10 µg/ml. GSE addition promoted GPx activity in both unstressed and stressed PMCs, while the expression of the GPx 1 gene displayed partial divergence with GPx activity, which was mitigated by GSE addition at 10 µg/ml in unstressed PMCs. GSH remained comparatively stable except for GSE addition to H2O2-stimulated PMCs at 60 µg/ml, in which a dramatic depletion of GSH occurred. Moreover, GSE addition enhanced TAOC in unstressed (but not H2O2-stimulated) PMCs. GSE addition exerted a bidirectional modulating effect on the mRNA levels and activities of CAT and SOD in unstressed and stressed PMCs at a moderate dose, and it only exhibited a unidirectional effect on the promotion of GPx activity, reflecting its potential to improve antioxidant protection in ruminants.