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.

Cloning, identification and functional analysis of the goat transcription factor c-fos / 生物工程学报

C-fos is a transcription factor that plays an important role in cell proliferation, differentiation and tumor formation. The aim of this study was to clone the goat c-fos gene, clarify its biological characteristics, and further reveal its regulatory role in the differentiation of goat subcutaneous adipocytes. We cloned the c-fos gene from subcutaneous adipose tissue of Jianzhou big-eared goats by reverse transcription-polymerase chain reaction (RT-PCR) and analyzed its biological characteristics. Using real-time quantitative PCR (qPCR), we detected the expression of c-fos gene in the heart, liver, spleen, lung, kidney, subcutaneous fat, longissimus dorsi and subcutaneous adipocytes of goat upon induced differentiation for 0 h to 120 h. The goat overexpression vector pEGFP-c-fos was constructed and transfected into the subcutaneous preadipocytes for induced differentiation. The morphological changes of lipid droplet accumulation were observed by oil red O staining and bodipy staining. Furthermore, qPCR was used to test the relative mRNA level of the c-fos overexpression on adipogenic differentiation marker genes. The results showed that the cloned goat c-fos gene was 1 477 bp in length, in which the coding sequence was 1 143 bp, encoding a protein of 380 amino acids. Protein structure analysis showed that goat FOS protein has a basic leucine zipper structure, and subcellular localization prediction suggested that it was mainly distributed in the nucleus. The relative expression level of c-fos was higher in the subcutaneous adipose tissue of goats (P < 0.05), and the expression level of c-fos was significantly increased upon induced differentiation of subcutaneous preadipocyte for 48 h (P < 0.01). Overexpression of c-fos significantly inhibited the lipid droplets formation in goat subcutaneous adipocytes, significantly decreased the relative expression levels of the AP2 and C/EBPβ lipogenic marker genes (P < 0.01). Moreover, AP2 and C/EBPβ promoter are predicted to have multiple binding sites. In conclusion, the results indicated that c-fos gene was a negative regulatory factor of subcutaneous adipocyte differentiation in goats, and it might regulate the expression of AP2 and C/EBPβ gene expression.

The effect of fat mass and obesity associated proteins mediated mRNA m6A modification on animal fat deposition and its application prospects / 生物工程学报

In the process of animal fat deposition, the proliferation and differentiation of pre-adipocytes and the change of lipid droplet content in adipocytes are regulated by a series of transcription factors and signal pathways. Although researchers have conducted in-depth studies on the transcriptional regulation mechanisms of adipogenesis, there are relatively few reports on post-transcriptional modification on mRNA levels. The modification of mRNA m6A regulated by methyltransferase, demethylase and methylation reading protein is a dynamic and reversible process, which is closely related to fat deposition in animals. Fat mass and obesity associated proteins (FTO) act as RNA demethylases that affect the expression of modified genes and play a key role in fat deposition. This article summarized the mechanism of FTO-mediated demethylation of mRNA m6A in the process of animal fat deposition, suggesting that FTO may become a target for effective treatment of obesity. Moreover, this review summarized the development of FTO inhibitors in recent years.

Knockdown of long non-coding RNA MIR4697 host gene inhibits adipogenic differentiation in bone marrow mesenchymal stem cells / 北京大学学报(医学版)

OBJECTIVE@#To preliminarily investigate the role of long non-coding RNA (lncRNA) MIR4697 host gene (MIR4697HG) in regulating the adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).@*METHODS@#For adipogenic differentiation, BMSCs were induced in adipogenic media for 10 days. The mRNA expression levels of lncRNA MIR4697HG and adipogenic marker genes including peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhanced binding protein α (CEBP/α) and adiponectin (ADIPQ) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) at different time points (0, 1, 2, 3, 5, 7, 10 days). The MIR4697HG stable knockdown-BMSC cell line was generated by infection of MIR4697HG shRNA-containing lentiviruses. To avoid off-target effect, two target sequences (shMIR4697HG-1, shMIR4697HG-2) were designed. And then cells were induced to differentiate in adipogenic medium. Oil red O staining, Western blot and qRT-PCR were used to detect the effect of MIR4697HG knockdown on adipogenic differentiation of BMSCs.@*RESULTS@#The mRNA expression level of MIR4697HG was significantly increased during adipogenic differentiation (P < 0.01), and adipogenic differentiation of BMSCs was evidenced by upregulated mRNA levels of specific adipogenesis-related genes including PPARγ, CEBP/α and ADIPQ. Observed by fluorescence microscopy, more than 90% transfected target cells expressed green fluorescent protein successfully after shMIR4697HG-1 group, shMIR4697HG-2 group and shNC group transfection for 72 h. And the transfection efficiency of MIR4697HG examined by qRT-PCR was above 60%. Then the BMSCs were treated with adipogenic media for 7 days and showed that the mRNA expression levels of adipogenesis-related genes including PPARγ, CEBP/α and ADIPQ were significantly decreased in the MIR4697HG knockdown group (P < 0.01), while the expression levels of PPARγ and CEBP/α proteins were decreased remarkably as well (P < 0.01). Consistently, MIR4697HG knockdown BMSCs formed less lipid droplets compared with the control BMSCs, which further demonstrated that MIR4697HG knockdown inhibited adipogenic differentiation of BMSCs.@*CONCLUSION@#lncRNA MIR4697HG played a crucial role in regulating the adipogenic differentiation of BMSCs, and MIR4697HG knockdown significantly inhibited the adipogenic differentiation of BMSCs. These data may suggest that lncRNA MIR4697HG could serve as a therapeutic potential target for the aberrant adipogenic differentiation-associated disorders including osteoporosis.

Expression regulation and functional analysis of RGS2 and RGS4 in adipogenic and osteogenic differentiation of human mesenchymal stem cells

BACKGROUND: Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs). RESULTS: Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation. CONCLUSIONS: RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.

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.

Characterization of human adipose-derived stem cells and expression of chondrogenic genes during induction of cartilage differentiation

OBJECTIVES: Understanding the changes in chondrogenic gene expression that are involved in the differentiation of human adipose-derived stem cells to chondrogenic cells is important prior to using this approach for cartilage repair. The aims of the study were to characterize human adipose-derived stem cells and to examine chondrogenic gene expression after one, two, and three weeks of induction. MATERIALS AND METHODS: Human adipose-derived stem cells at passage 4 were evaluated by flow cytometry to examine the expression of surface markers. These adipose-derived stem cells were tested for adipogenic and osteogenic differentiation capacity. Ribonucleic acid was extracted from the cells for quantitative polymerase chain reaction analysis to determine the expression levels of chondrogenic genes after chondrogenic induction. RESULTS: Human adipose-derived stem cells were strongly positive for the mesenchymal markers CD90, CD73, CD44, CD9, and histocompatibility antigen and successfully differentiated into adipogenic and osteogenic lineages. The human adipose-derived stem cells aggregated and formed a dense matrix after chondrogenic induction. The expression of chondrogenic genes (collagen type II, aggrecan core protein, collagen type XI, COMP, and ELASTIN) was significantly higher after the first week of induction. However, a significantly elevated expression of collagen type X was observed after three weeks of chondrogenic induction. CONCLUSION: Human adipose-derived stem cells retain stem cell characteristics after expansion in culture to passage 4 and serve as a feasible source of cells for cartilage regeneration. Chondrogenesis in human adiposederived stem cells was most prominent after one week of chondrogenic induction.

COL18A1 is highly expressed during human adipocyte differentiation and the SNP c.1136C > T in its "frizzled" motif is associated with obesity in diabetes type 2 patients

Collagen XVIII can generate two fragments, NC11-728 containing a frizzled motif which possibly acts in Wnt signaling and Endostatin, which is cleaved from the NC1 and is a potent inhibitor of angiogenesis. Collagen XVIII and Wnt signaling have recently been associated with adipogenic differentiation and obesity in some animal models, but not in humans. In the present report, we have shown that COL18A1 expression increases during human adipogenic differentiation. We also tested if polymorphisms in the Frizzled (c.1136C>T; Thr379Met) and Endostatin (c.4349G>A; Asp1437Asn) regions contribute towards susceptibility to obesity in patients with type 2 diabetes (113 obese, BMI =30; 232 non-obese, BMI < 30) of European ancestry. No evidence of association was observed between the allele c.4349G>A and obesity, but we observed a significantly higher frequency of homozygotes c.1136TT in obese (19.5 percent) than in non-obese individuals (10.9 percent) [P = 0.02; OR = 2.0 (95 percentCI: 1.07-3.73)], suggesting that the allele c.1136T is associated to obesity in a recessive model. This genotype, after controlling for cholesterol, LDL cholesterol, and triglycerides, was independently associated with obesity (P = 0.048), and increases the chance of obesity in 2.8 times. Therefore, our data suggest the involvement of collagen XVIII in human adipogenesis and susceptibility to obesity.

Colágeno XVIII pode gerar dois fragmentos, um correspondendo à região NC11-728 contendo o motivo ''frizzled'', o qual possivelmente atua na sinalização Wnt, e outro correspondendo a Endostatina, que é clivada a partir da região NC1 e é uma potente inibidora de angiogênese. Colágeno XVIII e a via de sinalização Wnt foram recentemente associados à diferenciação adipogênica e obesidade em alguns modelosanimais, porém ainda não em humanos. No presente trabalho, mostramos que os níveis de expressão gênica do COL18A1 aumentam durante o processo de diferenciação adipogênica em humanos. Também testamos se polimorfismos localizados no motivo ''Frizzled'' (c.1136C > T; Thr379Met) e na região da Endostatina (c.4349G > A; Asp1437Asn) contribuem na predisposição a obesidade em pacientes com diabetes tipo 2. (113 obesos, BMI > 30; 232 não-obesos, BMI < 30) de ancestralidade Européia. Nenhuma evidência de associação entre o alelo c.4349G > A e obesidade foi observada, contudo, observamos uma freqüência significativamente maior de homozigotos c.1136TT em obesos (19.5 por cento) do que em não-obesos (10.9 por cento)[P = 0.02; OR = 2.0 (95 por centoCI: 1.07-3.73)], sugerindo que o alelo c.1136T está associado com obesidade conforme ummodelo recessivo. Este genótipo manteve-se associado à obesidade (P = 0.048) mesmo após o controle das variáveis colesterol, LDL e triglicérides, e confere um risco 2.8 vezes maior de obesidade. Portanto, nossos dados sugerem o envolvimento do colágeno XVIII em adipogênese humana e predisposição a obesidade.

Expression and Regulation of Osteoprotegerin in Adipose Tissue

PURPOSE: Osteoprotegerin (OPG), a potent inhibitor of osteoclastic bone resorption, has a variety of biological functions that include anti-inflammatory effects. Adipocytes and osteoblasts share a common origin, and the formation of new blood vessels often precedes adipogenesis in developing adipose tissue microvasculature. We examined whether OPG is secreted from adipocytes, therefore contributing to the prevention of neovascularization and protecting the vessels from intimal inflammation and medial calcification. MATERIALS AND METHODS: The mRNA expression of OPG and receptor activator of NF-kappaB ligand (RANKL) was measured in differentiated 3T3L1 adipocytes and adipose tissues. RESULTS: OPG mRNA expression increased with the differentiation of 3T3L1 adipocytes, while RANKL expression was not significantly altered. OPG mRNA was expressed at higher levels in white adipose tissue than in brown adipose tissue and was most abundant in the epididymal portion. In differentiated 3T3L1 adipocytes, Rosiglitazone and insulin reduced the OPG/RANKL expression ratio in a dose- and time- dependent manner. In contrast, tumor necrosis factor-alpha (TNF-alpha) increased the expression of both OPG and RANKL in a time-dependent manner. The OPG/RANKL ratio was at a maximum two hours after TNF-alpha treatment and then returned to control levels. Furthermore, OPG was abundantly secreted into the media after transfection of OPG cDNA with Phi C31 integrase into 3T3L1 cells. CONCLUSION: Our results indicate that OPG mRNA is expressed and regulated in the adipose tissue. Considering the role of OPG in obesity-associated inflammatory changes in adipose tissue and vessels, we speculate that OPG may have both a protective function against inflammation and anti-angiogenic effects on adipose tissue.