Junjing Jia

The polymorphisms of UCP2 and UCP3 genes associated with fat metabolism, obesity and diabetes

Uncoupling proteins (UCPs) belong to the family of mitochondrial transporter proteins that may uncouple the transport of protons across the inner mitochondrial membrane from electron transport and the synthesis of ATP from ADP, hence generating heat rather than energy. In mammals, more than five family members have been identified, including UCP1, UCP2, UCP3, UCP4 (or BMCP1/UCP5) and UCP5. The UCPs may play an important role in energy homeostasis and have become prominent in the fields of thermogenesis, obesity, diabetes and free‐radical biology and have been considered candidate genes for obesity and insulin resistance. They have been as important potential targets for treatment of aging, degenerative diseases, diabetes and obesity. Recently, a series of studies showed the polymorphisms of UCPs gene association with the fat metabolism, obesity and diabetes. This review summarizes data supporting the roles of UCP2 and UCP3 in energy dissipation, as well as the genetic variety association with fat metabolism, obesity and diabetes in humans.

The polymorphisms of UCP1 genes associated with fat metabolism, obesity and diabetes

Uncoupling protein 1 (UCP1), a 32-kDa protein located in the inner mitochondrial membrane, is abundant in brown adipose tissue, as a proton transporter in mitochondria inner membrane which uncouples oxidative metabolism from ATP synthesis and dissipates energy through the heat. UCP1 has been reported to play important roles for energy homeostasis in rodents and neonate of larger mammals including human. Recently, numerous candidate genes were searched to determine the genetic factors implicated in the pathogenesis of obesity, related metabolic disorders and diabetes. UCP-1, which plays a major role in thermogenesis, was suggested to be one of the candidates. This review summarizes data supporting the existence of brown adipocytes and the role of UCP1 in energy dissipation in adult humans, and the genetic variety association with the fat metabolism, obesity and diabetes.

Effect of pu-erh tea on body fat and lipid profiles in rats with diet-induced obesity.

The antiobesity and antihyperlipidaemic effects of pu‐erh tea in rats with high fat diet (HFD)‐induced obesity were investigated. Male Sprague‐Dawley rats were randomly divided into five groups and fed varying diets for an 8‐week period: control diet, HFD, and HFD supplemented with low, moderate or high doses of pu‐erh tea extract (0.5 g, 2 g and 4 g/kg BW/day, respectively). Pu‐erh tea significantly reduced the total body weight and the weight of various adipose pads. Pu‐erh tea administration also significantly lowered plasma total cholesterol, triglyceride concentrations and low‐density lipoprotein‐cholesterol levels in rats with HFD‐induced obesity, but did not affect high‐density lipoprotein‐cholesterol levels. Moreover, pu‐erh tea significantly increased lipoprotein lipase, hepatic lipase and hormone‐sensitive lipase activities in epididymal fat tissue in rats with HFD‐induced obesity. Analysis of real‐time reverse transcription‐polymerase chain reaction results indicated that pu‐erh tea significantly enhanced mRNA levels of hormone‐sensitive lipase in rats with HFD‐induced obesity. These results suggest that pu‐erh tea attenuated visceral fat accumulation and improved hyperlipidemia in a rat model of HFD‐induced obesity. Copyright

Effects of Aqueous Extracts of Raw Pu-erh Tea and Ripened Pu-Erh Tea on Proliferation and Differentiation of 3T3-L1 Preadipocytes

Pu‐erh tea has shown anti‐obesity effects but little is known about its effect on proliferation and differentiation of preadipocytes. This study investigated the effects of the aqueous extracts of raw pu‐erh tea and ripened pu‐erh tea on proliferation and differentiation of murine 3T3‐L1 preadiopocytes. We examined dose and time effects of both aqueous extracts on proliferation of 3T3‐L1 preadipocytes. The contents of triglycerides in cytoplasm and the mRNA expression of critical transcriptional factors involved in differentiation were determined. Cytotoxicity and apoptosis rate of preadipocytes by pu‐erh tea extracts treatment were test for toxic and pro‐apoptotic effects. Both aqueous extracts of pu‐erh tea inhibited the proliferation of 3T3‐L1 preadipocytes at the selected time points. At lower concentration of raw pu‐erh tea extracts (less than 300 µg/ml) and ripened pu‐erh tea extracts (less than 350 µg/ml), no significant cytotoxic and pro‐apoptotic were observed. Ripened pu‐erh tea was more effective with lower IC50 than raw pu‐erh tea. Both extracts suppressed the differentiation and down‐regulated the gene expression of peroxisome proliferator‐activated receptor‐γ and CCAAT/enhancer binding proteins‐α. Therefore, these results indicate that both aqueous extracts of pu‐erh tea can inhibit proliferation and differentiation with ripened pu‐erh tea more potent. Polyphenol rich in both extracts may play a role in the inhibition of proliferation and differentiation of 3T3‐L1 preadipocytes. Copyright

Biological mechanisms discriminating growth rate and adult body weight phenotypes in two Chinese indigenous chicken breeds

BackgroundIntensive selection has resulted in increased growth rates and muscularity in broiler chickens, in addition to adverse effects, including delayed organ development, sudden death syndrome, and altered metabolic rates. The biological mechanisms underlying selection responses remain largely unknown. Non-artificially-selected indigenous Chinese chicken breeds display a wide variety of phenotypes, including differential growth rate, body weight, and muscularity. The Wuding chicken breed is a fast growing large chicken breed, and the Daweishan mini chicken breed is a slow growing small chicken breed. Together they form an ideal model system to study the biological mechanisms underlying broiler chicken selection responses in a natural system. The objective of this study was to study the biological mechanisms underlying differential phenotypes between the two breeds in muscle and liver tissues, and relate these to the growth rate and body development phenotypes of the two breeds.ResultsThe muscle tissue in the Wuding breed showed higher expression of muscle development genes than muscle tissue in the Daweishan chicken breed. This expression was accompanied by higher expression of acute inflammatory response genes in Wuding chicken than in Daweishan chicken. The muscle tissue of the Daweishan mini chicken breed showed higher expression of genes involved in several metabolic mechanisms including endoplasmic reticulum, protein and lipid metabolism, energy metabolism, as well as specific immune traits than in the Wuding chicken. The liver tissue showed fewer differences between the two breeds. Genes displaying higher expression in the Wuding breed than in the Daweishan breed were not associated with a specific gene network or biological mechanism. Genes highly expressed in the Daweishan mini chicken breed compared to the Wuding breed were enriched for protein metabolism, ABC receptors, signal transduction, and IL6-related mechanisms.ConclusionsWe conclude that faster growth rates and larger body size are related to increased expression of genes involved in muscle development and immune response in muscle, while slower growth rates and smaller body size are related to increased general cellular metabolism. The liver of the Daweishan breed displayed increased expression of metabolic genes.

Growth arrest induction of 3T3-L1 preadipocytes by serum starvation and their differentiation by the hormonal adipogenic cocktail

The current methods for differentiation of 3T3-L1 preadipocytes start with growth arrest by contact inhibition. However, on day 6, 3T3-L1 preadipocytes reliably detach and differentiation could no longer proceed. In the present study, we used serum starvation to induce growth arrest in 3T3-L1 preadipocytes and investigated their differentiation by the modified hormonal adipogenic cocktail. About 85% of 3T3-L1 cells were in G0/G1 stage under serum deprivation. There were no significant difference between the percentage of cells in G0/G1 phase under these serum deprivation condition and that of post-confluent cells. Growth assays indicated that cells under serum starvation condition grew slow, two-days later than growing and post-confluent cells. We determined that 0.5% FBS for 48 h was the optimal condition to arrest 3T3-L1 cells at the G0/G1 phase. The grow-arrested 3T3-L1 preadipocytes were induced to differentiation by hormonal adipogenic cocktail. After 19 days of differentiation, over 90% 3T3-L1 cells exhibited adipocyte morphology with ring-like lipid droplet in cytoplasm. The mRNA levels of critical transcriptional factor CCAAT/enhancer binding proteins-α and peroxisome proliferator-activated receptor-γ were determined to validate the differentiation. These results indicated that serum starvation effectively arrested the growth of 3T3-L1 preadipocytes and prevented cells from detachemnt caused by contact inhibition at confluence. Furthermore, growth arrested 3T3-L1 preadipocytes by serum starvation successfully differentiated into adipocytes by the hormonal adipogenic cocktail.

Effect of Crossbreed on the Muscle Quality （Chemical Composition） in Yun- Ling Black Goats

Twenty castrated male goats, each of Yun-Ling Black goats (YLB goat), N × YLB hybrid goats (Nubian ♂× Yun-Ling Black goats♀) and B × YLB hybrid goats (Boer ♂× Yun-Ling Black goats♀), were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi (LD) and biceps femoris (BF) muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content (P＜0.01) and lower fat content (P＜0.05) than the YLB goats in the two types of muscle. The inosinic acid contents of LD muscle for the YLB goats and the B×YLB hybrid goats were significantly higher (P＜0.05) than that for the N×YLB hybrid goats. The LD muscle from the YLB goats contained higher essential amino acid (P＜0.01), total amino acid (P＜0.01), and some individual amino acid (P＜0.05) than those from the hybrid goats. The concentration of unsaturated fatty acid (USFA) of LD muscle from the N×YLB hybrid goats was significantly higher than the other two goat breeds (P＜0.05) but did not differ between the other two goat breeds (P＞0.05). The YLB goats had significantly higher (P＜0.05) concentrations of oleic acid (C18:1) and linolenic acid (C18:3) of LD muscle than the hybrid goats, had significantly higher (P＜0.05) proportion of mono-unsaturated (Sum for C16:1 and C18:1) than the B×YLB hybrid goats, and tended to be higher than the N×YLB hybrid goats (P＞0.05). In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower (P＜0.05) than that in the hybrid goats.

Comparison and analysis of Wuding and avian chicken skeletal muscle satellite cells

Chicken skeletal muscle satellite cells are located between the basement membrane and the sarcolemma of mature muscle fibers. Avian broilers have been genetically selected based on their high growth velocity and large muscle mass. The Wuding chicken is a famous local chicken in Yunnan Province that undergoes non-selection breeding and is slow growing. In this study, we aimed to explore differences in the proliferation and differentiation properties of satellite cells isolated from the two chicken breeds. Using immunofluorescence, hematoxylin-eosin staining and real-time polymerase chain reaction analysis, we analyzed the in vitro characteristics of proliferating and differentiating satellite cells isolated from the two chicken breeds. The growth curve of satellite cells was S-shaped, and cells from Wuding chickens entered the logarithmic phase and plateau phase 1 day later than those from Avian chicken. The results also showed that the two skeletal muscle satellite cell lines were positive for Pax7, MyoD and IGF-1. The expression of Pax7 followed a downward trend, whereas that of MyoD and IGF-1 first increased and subsequently decreased in cells isolated from the two chickens. These data indicated that the skeletal muscle satellite cells of Avian chicken grow and differentiate faster than did those of Wuding chickens. We suggest that the methods of breeding selection applied to these breeds regulate the characteristics of skeletal muscle satellite cells to influence muscle growth.

In Vitro Evaluation of Probiotic Potential of Lactic Acid Bacteria Isolated from Yunnan De’ang Pickled Tea

This study aimed to investigate the probiotic potential of lactic acid bacteria (LAB) strains isolated from De’ang pickled tea, a traditional food consumed by the De’ang nationality of Yunnan, China. Twenty-six LAB strains isolated from De’ang pickled tea were subjected to identification based on 16S rRNA gene sequence analysis. Twenty-four belonged to Lactobacillus plantarum, one belonged to Enterococcus casseliflavus, and one belonged to Lactobacillus acidophilus. Eighteen out of 26 LAB strains which showed a higher capability to tolerate simulated gastrointestinal juices were chosen to further evaluate their probiotic properties. Varied adhesive abilities and auto-aggregative capacities of selected LAB strains were dependent on species and even strains. All tested LAB strains were resistant to kanamycin, streptomycin, gentamycin, and vancomycin and sensitive to tetracycline and chloramphenicol. Ten out of the 18 strains are resistant to ampicillin, and the remaining strains are sensitive to ampicillin; 4 out of the 18 strains showed resistance to erythromycin. Compared to reference strain Lactobacillus rhamnosus strain GG, these LAB strains had a greater or comparative antimicrobial activity against Salmonella typhimurium or Escherichia coli. In contrast, eight out of the 18 strains suppressed growth of Shigella flexneri. Two L. plantarum strains, ST and STDA10, not only exhibited good probiotic properties but also showed a good ability of scavenging DPPH and ABTS+. This study suggests that L. plantarum ST and STDA10 could be used as potential probiotics applied in functional foods.

Selection for growth rate and body size have altered the expression profiles of somatotropic axis genes in chickens

The growth hormone / insulin-like growth factor-1 (GH/IGF-1) pathway of the somatotropic axis is the major controller for growth rate and body size in vertebrates, but the effect of selection on the expression of GH/IGF-1 somatotropic axis genes and their association with body size and growth performance in farm animals is not fully understood. We analyzed a time series of expression profiles of GH/IGF-1 somatotropic axis genes in two chicken breeds, the Daweishan mini chickens and Wuding chickens, and the commercial Avian broilers hybrid exhibiting markedly different body sizes and growth rates. We found that growth rate and feed conversion efficiency in Daweishan mini chickens were significantly lower than those in Wuding chickens and Avian broilers. The Wuding and Daweishan mini chickens showed higher levels of plasma GH, pituitary GH mRNA but lower levels of hepatic growth hormone receptor (GHR) mRNA than in Avian broilers. Daweishan mini chickens showed significantly lower levels of plasma IGF-1, thigh muscle and hepatic IGF-1 mRNA than did Avian broilers and Wuding chickens. These results suggest that the GH part of the somatotropic axis is the main regulator of growth rate, while IGF-1 may regulate both growth rate and body weight. Selection for growth performance and body size have altered the expression profiles of somatotropic axis genes in a breed-, age-, and tissue-specific manner, and manner, and alteration of regulatory mechanisms of these genes might play an important role in the developmental characteristics of chickens.