Gene cloning and sequence analysis of the RPL29 gene and its effect on lipogenesis in goat intramuscular adipocytes / 生物工程学报

The aim of this study was to clone the goat RPL29 gene and analyze its effect on lipogenesis in intramuscular adipocytes. Using Jianzhou big-eared goats as the object, the goat RPL29 gene was cloned by reverse transcription-polymerase chain reaction (RT-PCR), the gene structure and expressed protein sequence were analyzed by bioinformatics, and the mRNA expression levels of RPL29 in various tissues and different differentiation stages of intramuscular adipocytes of goats were detected by quantitative real-time PCR (qRT-PCR). The RPL29 overexpression vector pEGFP-N1-RPL29 constructed by gene recombination was used to transfect into goat intramuscular preadipocytes and induce differentiation. Subsequently, the effect of overexpression of RPL29 on fat droplet accumulation was revealed morphologically by oil red O and Bodipy staining, and changes in the expression levels of genes related to lipid metabolism were detected by qRT-PCR. The results showed that the length of the goat RPL29 was 507 bp, including a coding sequence (CDS) region of 471 bp which encodes 156 amino acid residues. It is a positively charged and stable hydrophilic protein mainly distributed in the nucleus of cells. Tissue expression profiling showed that the expression level of this gene was much higher in subcutaneous adipose tissue and inter-abdominal adipose tissue of goats than in other tissues (P < 0.05). The temporal expression profile showed that the gene was expressed at the highest level at 84 h of differentiation in goat intramuscular adipocytes, which was highly significantly higher than that in the undifferentiated period (P < 0.01). Overexpression of RPL29 promoted lipid accumulation in intramuscular adipocytes, and the optical density values of oil red O staining were significantly increased (P < 0.05). In addition, overexpression of RPL29 was followed by a highly significant increase in ATGL and ACC gene expression (P < 0.01) and a significant increase in FASN gene expression (P < 0.05). In conclusion, the goat RPL29 may promote intra-muscular adipocyte deposition in goats by up-regulating FASN, ACC and ATGL.

Liver structural injury in leptin-deficient (ob/ob) mice: lipogenesis, fibrogenesis, inflammation, and apoptosis / Lesión estructural del hígado en ratones con deficiencia de leptina (ob/ob): lipogénesis, fibrogénesis, inflamación y apoptosis

SUMMARY: Nonalcoholic fatty liver disease (NAFLD) might progress the steatosis to nonalcoholic steatohepatitis (NASH), reaching a cirrhosis state and possibly hepatocellular carcinoma. The liver of three-month-old C57BL/6J mice (wild-type, WT group, n=10) and leptin- deficient obese mice (ob/ob group, n=10) were studied, focusing on the mechanisms associated with the activation of the hepatic stellate cells (HSCs) and pro-fibrogenesis. The obese ob/ob animals' liver showed steatosis, increased lipogenesis gene expressions, inflammation, increased pro-inflammatory gene expressions, inflammatory infiltrate, and potential apoptosis linked to a high Caspase 3 expression. In ob/ob mice, liver sections were labeled in the fibrotic zones by anti-alpha-smooth muscle actin (alpha-SMA) and anti-Reelin, but not in the WT mice. Moreover, the alpha-SMA gene expression was higher in the ob/ob group's liver than the WT group. The pro-fibrogenic gene expressions were parallel to anti- alpha-SMA and anti-Reelin immunofluorescence, suggesting HSCs activation. In the ob/ob animals, there were increased gene expressions involved with lipogenesis (Peroxisome proliferator-activated receptor-gamma, Cell death-inducing DFFA-like effector-c, Sterol regulatory element-binding protein-1c, and Fatty acid synthase), pro-fibrogenesis (Transforming growth factor beta1, Smad proteins- 3, Yes-associated protein-1, Protein platelet-derived growth factor receptor beta), pro-inflammation (Tumor necrosis factor-alpha, and Interleukin-6), and apoptosis (Caspase 3). In conclusion, the results in obese ob/ob animals provide a clue to the events in humans. In a translational view, controlling these targets can help mitigate the hepatic effects of human obesity and NAFLD progression to NASH.

RESUMEN: La enfermedad del hígado graso no alcohólico (HGNA) puede progresar de la esteatosis a esteatohepatitis no alcohólica (ENA), alcanzando un estado de cirrosis y posiblemente carcinoma hepatocelular. Se estudió el hígado de ratones C57BL / 6J de tres meses de edad (tipo salvaje, grupo WT, n = 10) y ratones obesos con deficiencia de leptina (grupo ob/ob, n = 10), centrándose en los mecanismos asociados con la activación de las células estrelladas hepáticas (HSC) y profibrogénesis. El hígado de los animales obesos ob/ob mostró esteatosis, aumento de la expresión génica de la lipogénesis, inflamación, aumento de la expresión génica proinflamatoria, infiltrado inflamatorio y posible apoptosis ligada a una alta expresión de Caspasa 3. En ratones ob/ob, las sec- ciones de hígado se marcaron en las zonas fibróticas con anti-alfa- actina de músculo liso (alfa-SMA) y anti-Reelin, pero no en los ratones WT. Además, la expresión del gen alfa-SMA fue mayor en el hígado del grupo ob/ob que en el grupo WT. Las expresiones génicas profibrogénicas fueron paralelas a la inmunofluorescencia anti-alfa-SMA y anti-Reelin, lo que sugiere la activación de las HSC. En los animales ob/ob, hubo un aumento de las expresiones génicas involucradas con la lipogénesis (receptor activado por proliferador de peroxisoma gamma, efector c similar a DFFA inductor de muerte celular, proteína de unión al elemento regulador de esterol-1c y sintasa de ácidos grasos), pro-fibrogénesis (factor de crecimiento transformante beta 1, proteínas Smad-3, proteína-1 asociada a Yes, receptor beta del factor de crecimiento derivado de plaquetas de proteínas), proinflamación (factor de necrosis tumoral alfa e interleucina-6) y apoptosis (caspasa 3). ). En conclusión, los resultados en animales obesos ob/ob proporcionan una pista de los eventos en humanos. Desde un punto de vista traslacional, el control de estos objetivos puede ayudar a mitigar los efectos hepáticos de la obesidad humana y la progresión de HGNA a ENA.

Effect of dietary nutrition on tail fat deposition and evaluation of tail-related genes in fat-tailed sheep

BACKGROUND: The effects of dietary nutrition on tail fat deposition and the correlation between production performance and the Hh signaling pathway and OXCT1 were investigated in fat-tailed sheep. Tan sheep were fed different nutritional diets and the variances in tail length, width, thickness and tail weight as well as the mRNA expression of fat-related genes (C/EBPα, FAS, LPL, and HSL) were determined in the tail fat of sheep at three different growth stages based on their body weight. Furthermore, the correlations between tail phenotypes and the Hedgehog (Hh) signaling pathway components (IHH, PTCH1, SMO, and GLI1) and OXCT1 were investigated. RESULTS: C/EBPα, FAS, LPL, and HSL were expressed with differences in tail fat of sheep fed different nutritional diets at three different growth stages. The results of the two-way ANOVA showed the significant effect of nutrition, stage, and interaction on gene expression, except the between C/EBPα and growth stage. C/EBPα, FAS, and LPL were considerably correlated with the tail phenotypes. Furthermore, the results of the correlation analysis demonstrated a close relationship between the tail phenotypes and Hh signaling pathway and OXCT1. CONCLUSIONS: The present study demonstrated the gene-level role of dietary nutrition in promoting tail fat deposition and related tail fat-related genes. It provides a molecular basis by which nutritional balance and tail fat formation can be investigated and additional genes can be identified. The findings of the present study may help improve the production efficiency of fat-tailed sheep and identify crucial genes associated with tail fat deposition.

Duodenal-jejunal bypass normalizes pancreatic islet proliferation rate and function but not hepatic steatosis in hypothalamic obese rats

Modifications in life-style and/or pharmacotherapies contribute to weight loss and ameliorate the metabolic profile of diet-induced obese humans and rodents. Since these strategies fail to treat hypothalamic obesity, we have assessed the possible mechanisms by which duodenal-jejunal bypass (DJB) surgery regulates hepatic lipid metabolism and the morphophysiology of pancreatic islets, in hypothalamic obese (HyO) rats. During the first 5 days of life, male Wistar rats received subcutaneous injections of monosodium glutamate (4 g/kg body weight, HyO group), or saline (CTL). At 90 days of age, HyO rats were randomly subjected to DJB (HyO DJB group) or sham surgery (HyO Sham group). HyO Sham rats were morbidly obese, insulin resistant, hypertriglyceridemic and displayed higher serum concentrations of non-esterified fatty acids (NEFA) and hepatic triglyceride (TG). These effects were associated with higher expressions of the lipogenic genes and fatty acid synthase (FASN) protein content in the liver. Furthermore, hepatic genes involved in β-oxidation and TG export were down-regulated in HyO rats. In addition, these rats exhibited hyperinsulinemia, β-cell hypersecretion, a higher percentage of islets and β-cell area/pancreas section, and enhanced nuclear content of Ki67 protein in islet-cells. At 2 months after DJB surgery, serum concentrations of TG and NEFA, but not hepatic TG accumulation and gene and protein expressions, were normalized in HyO rats. Insulin release and Ki67 positive cells were also normalized in HyO DJB islets. In conclusion, DJB decreased islet-cell proliferation, normalized insulinemia, and ameliorated insulin sensitivity and plasma lipid profile, independently of changes in hepatic metabolism.

BAFF knockout improves systemic inflammation via regulating adipose tissue distribution in high-fat diet-induced obesity

Obesity is recognized as a chronic low-grade inflammatory state due to adipose tissue expansion being accompanied by an increase in the production of proinflammatory adipokines. Our group is the first to report that B-cell-activating factor (BAFF) is produced from adipocytes and functions as a proinflammatory adipokine. Here, we investigated how loss of BAFF influenced diet-induced obesity in mice by challenging BAFF-/- mice with a high-fat diet for 10 weeks. The results demonstrated that weight gain in BAFF-/- mice was >30% than in control mice, with a specific increase in the fat mass of the subcutaneous region rather than the abdominal region. Expression of lipogenic genes was examined by quantitative real-time PCR, and increased lipogenesis was observed in the subcutaneous adipose tissue (SAT), whereas lipogenesis in the epididymal adipose tissue (EAT) was reduced. A significant decrease in EAT mass resulted in the downregulation of inflammatory gene expression in EAT, and more importantly, overall levels of inflammatory cytokines in the circulation were reduced in obese BAFF-/- mice. We also observed that the macrophages recruited in the enlarged SAT were predominantly M2 macrophages. 3T3-L1 adipocytes were cultured with adipose tissue conditioned media (ATCM), demonstrating that EAT ATCM from BAFF-/- mice contains antilipogenic and anti-inflammatory properties. Taken together, BAFF-/- improved systemic inflammation by redistributing adipose tissue into subcutaneous regions. Understanding the mechanisms by which BAFF regulates obesity in a tissue-specific manner would provide therapeutic opportunities to target obesity-related chronic diseases.

Physical training prevents body weight gain but does not modify adipose tissue gene expression

The relationship of body weight (BW) with white adipose tissue (WAT) mass and WAT gene expression pattern was investigated in mice submitted to physical training (PT). Adult male C57BL/6 mice were submitted to two 1.5-h daily swimming sessions (T, N = 18), 5 days/week for 4 weeks or maintained sedentary (S, N = 15). Citrate synthase activity increased significantly in the T group (P < 0.05). S mice had a substantial weight gain compared to T mice (4.06 ± 0.43 vs 0.38 ± 0.28 g, P < 0.01). WAT mass, adipocyte size, and the weights of gastrocnemius and soleus muscles, lung, kidney, and adrenal gland were not different. Liver and heart were larger and the spleen was smaller in T compared to S mice (P < 0.05). Food intake was higher in T than S mice (4.7 ± 0.2 vs 4.0 ± 0.3 g/animal, P < 0.05) but oxygen consumption at rest did not differ between groups. T animals showed higher serum leptin concentration compared to S animals (6.37 ± 0.5 vs 3.11 ± 0.12 ng/mL). WAT gene expression pattern obtained by transcription factor adipocyte determination and differentiation-dependent factor 1, fatty acid synthase, malic enzyme, hormone-sensitive lipase, adipocyte lipid binding protein, leptin, and adiponectin did not differ significantly between groups. Collectively, our results showed that PT prevents BW gain and maintains WAT mass due to an increase in food intake and unchanged resting metabolic rate. These responses are closely related to unchanged WAT gene expression patterns.