BACKGROUND: Hyperglycemia and insulin resistance are among the key phenotypes of obesity and type 2 diabetes (T2DM). Notably, skeletal muscle fiber-type composition is closely linked to insulin resistance. Vascular endothelial growth factor B (VEGF-B) has been shown to play an important role in T2DM. However, the effects of VEGF-B on myofiber types in individuals with obesity or T2DM remain unclear. This study aimed to investigate the effects and mechanisms of VEGF-B on myofiber-type formation and regeneration. METHODS: Male Vegfb (vascular endothelial growth factor B) gene knockout mice and wild-type C57BL/6 male mice were fed either a normal diet or a high-fat diet. Double immunofluorescence staining and RNA-seq of skeletal muscle tissue from these mice were used to evaluate the role of VEGF-B in myofiber type regulation. To investigate the effects of VEGF-B on myoblast differentiation, fusion, and type I slow-twitch fiber formation in vitro, we prepared a novel in vitro model by continuous single-dose administration of VEGF-B, which was matched with physiological conditions and high-fat diet-induced hyperglycemia in vivo. RESULTS: VEGF-B deficiency attenuated high-fat diet-induced loss of slow-twitch type I myofibers and improved hyperglycemia and insulin resistance in mice. Continuous low-concentration administration of VEGF-B isoforms (VEGF-B186 and VEGF-B167) enhanced myoblast differentiation, fusion and myotube formation in a dose-dependent manner, whereas higher concentrations inhibited these processes, with VEGF-B186 exhibiting more pronounced effects. Notably, elevated VEGF-B levels, particularly VEGF-B186, suppressed mainly slow-twitch type I myofiber formation. Mechanistic studies revealed that high-dose VEGF-B186 (100 ng/mL) reduced myoblast differentiation/fusion and slow-twitch fiber formation via PKA-NFAT-MyoG/MEF2C signaling. Furthermore, high-dose VEGF-B186 decreased the expression of glucose transporter type 4, glucose utilization, and mitochondrial function in a unique myoblast cell model, effects that were reversed by PKA activators and NFATc1/c2 overexpression. CONCLUSION: These findings demonstrate that VEGF-B is a key regulator of myofiber type composition and metabolic homeostasis in the context of obesity or T2DM. The inhibitory effects of elevated VEGF-B186 on slow-twitch fiber formation and glucose metabolism underscore its pathological role in obesity-related metabolic dysregulation. These results support the therapeutic potential of targeting VEGF-B186—via inhibitors or monoclonal antibodies— for obesity and T2DM, which are characterized by slow-twitch fiber depletion.

Species distribution and activity patterns vary across regions, and these patterns reveal key information about the biology of a given species. However, such data in Niubeiliang National Nature Reserve located in the Qinling Mountains, Shaanxi Province, China, are inadequate due to limited monitoring studies. From September 2017 to December 2019, 57 infrared cameras were installed to monitor species distribution relative to distance from National Highway 210, and spatial and temporal activity patterns in Niubeiliang National Nature Reserve (elevation range 1,100 to 2,802 m). Sixteen species of mammals were recorded in our survey. The 4 most frequently detected species were Reeves's Muntjac (Muntiacus reevesi), Wild Boar (Sus scrofa), Pere David's Rock Squirrel (Sciurotamias davidianus), and Golden Takin (Budorcas taxicolor bedfordi). Daily patterns of these species indicated that Reeves's muntjacs and golden takins were more active at dawn and dusk, whereas wild boars and Pere David's rock squirrels were more active during the day. The relative abundance index of these mammals varied seasonally. Wild boars and Pere David's rock squirrels showed no obvious preference in elevation distribution, Reeves's muntjacs preferred low-elevation habitats (1,300 to 1,600 m), and golden takins mainly inhabited high-elevation areas (1,900 to 2,100 m). Golden takins showed obvious avoidance of roads, with avoidance distance from the road of >300 m. In contrast, Reeves's muntjacs were remarkably abundant within 200 m of the road. For both wild boars and Pere David's rock squirrels, there was no significant difference in RAI among 5 highway ranges. These findings help describe the distribution and activity patterns of these species in Qinling, to monitor their population dynamics, and to develop tailored conservation strategies for the 4 species and sympatric wildlife.

诱导细胞凋亡DFF45样效应子a(cell death inducing DNA fragmentation factor 45 like effector a,CIDEa)是一类和脂类代谢紧密相关的蛋白,参与调控脂解、脂滴的生长融合和极低密度脂蛋白的成熟.为研究CIDEa基因在奶山羊(Capra hircus)乳腺上皮细胞中的生物学功能,本研究利用qPCR技术检测CIDEa在奶山羊泌乳期和干奶期乳腺组织的表达差异;采用siRNA介导的干扰技术研究CIDEa基因对脂质合成和相关基因表达的影响.结果发现,CIDEa基因在泌乳期乳腺组织的表达量显著高于干奶期(P<0.05).利用siRNA介导的干扰技术,在奶山羊乳腺上皮细胞中转染siRNA,CIDEa基因mRNA水平下调60％～88％(P<0.01);干扰CIDEa,抑制了细胞中脂滴积累,显著降低细胞中甘油三酯含量(P<0.05);CIDEa干扰后,显著上调脂肪酸合酶(fatty acid synthase,FASN)和激素敏感脂酶(hormone-sensitive lipase,HSL)基因的表达(P<0.05),同时促进固醇调节元件结合蛋白1(sterol regulatory element binding proteins 1,SREBP1)基因的表达(P<0.05),并且抑制脂肪酸结合蛋白3(fatty acid-binding protein 3,FABP3)和二酰基甘油酰基转移酶1(diacylglycerol acyltransferase 1,DGAT1)基因的表达(P<0.05).研究结果表明,CIDEa基因在奶山羊乳腺上皮细胞中促进脂滴合成,本研究为进一步研究CIDEa调控奶山羊乳脂合成的作用机制提供理论依据.

An increasing number of researches have shown that cell metabolism regulates cell function. Dendritic cells (DCs), a professional antigen presenting cells, connect innate and adaptive immune responses. The preference of DCs for sugar or lipid affects its phenotypes and functions. In many diseases such as atherosclerosis (AS), diabetes mellitus and tumor, altered glucose or lipid level in microenvironment makes DCs exert ineffective or opposite immune roles, which accelerates the development of these diseases. In this article, we review the metabolism pathways of glucose and cholesterol in DCs, and the effects of metabolic changes on the phenotype and function of DCs. In addition, we discuss the effects of changes in glucose and lipid levels on DCs in the context of different diseases for better understanding the relationship between DCs and diseases. The immune metabolism of DCs may be a potential intervention link to treat metabolic-related immune diseases.

本研究旨在克隆奶山羊(Capra hircus)中链脂肪酸受体GPR84基因并分析其在不同组织及不同泌乳时期的表达情况,为进一步探讨其生理功能奠定基础.根据GenBank上已登录的牛、人、鼠等物种的GPR84基因序列设计一对特异性引物,利用RT-PCR方法克隆奶山羊GPR84基因的CDS,利用实时荧光定量PCR方法分析奶山羊GPR84基因的组织表达谱.测序结果表明奶山羊GPR84基因CDS为1191 bp,编码396个氨基酸.序列同源性分析表明:奶山羊的GPR84基因核苷酸序列与牛(NM_001038568.1)、人(NM_020370.2)、鼠(NM_030720.1)的相似性分别为96％、88％和82％.实时定量分析结果表明脾脏是GPR84表达量最高的组织,然后是小肠和瘤胃组织,在皮下脂肪、肺脏、乳腺组织中的表达量相对较少,心脏组织中的表达量最少.奶山羊不同泌乳时期乳腺组织表达分析表明GPR84基因在泌乳盛期和泌乳中期的表达量显著高于其它泌乳阶段(P＜0.05),而泌乳前期和后期表达量相对较少.本研究结果表明GPR84具有一定的组织表达特异性,并且GPR84可能在泌乳的乳腺组织中发挥着重要的生理作用.

Atherosclerosis (AS) is characterized by dyslipidemia and chronic inflammation. In the high-fat environment, the lipid metabolism of dendritic cells (DCs) is abnormal, which leads to abnormal immune function, promotes the occurrence of immune inflammatory reactions, and promotes the development of AS. Alisol B 23-acetate (23B) is a triterpenoid in the rhizomes of Alisma, which is a traditional Chinese medicine. Here, we identified cholesterol metabolism-related targets of 23B through a virtual screen, and further transcriptome analysis revealed that 23B can change antigen presentation and cholesterol metabolism pathways in cholesterol-loaded DCs. In vitro experiments confirmed that 23B promoted cholesterol efflux from ApoE-/- DCs, reduced the expression of MHC II, CD80, and CD86, and inhibited the activation of CD4+ T cells and the production of inflammatory cytokines IL-12 and IFN-γ. In advanced AS mice, 23B can decrease triacylglycerol (TG) levels and increase high-density lipoprotein-cholesterol (HDL-C) levels in plasma and the expression of cholesterol efflux genes in the aorta. Neither helper T cells 1 (Th1) nor regulatory T cells (Tregs) in peripheral blood changed significantly in the presence of 23B, but 23B reduced the levels of IL-12 and IFN-γ in serum. However, 23B did not change the total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels in serum or lipid accumulation in the aorta. Moreover, 23B did not increase the production of IL-10 and TGF-β1 in vivo or in vitro. These results indicate that 23B promotes cholesterol efflux from DCs, which can improve the immune inflammatory response and contribute to controlling the inflammatory status of AS.

Background Atherosclerosis (AS), which characterized with the accumulation of lipids on the vessel wall, is the pathological basis of many cardiovascular diseases (CVD) and seriously threatens human health. Resveratrol (RES) has been reported to be benefit for AS treatment. This research aimed to observe the effects of RES on AS induced by high-fat diet (HFD) and LPS in ApoE −/− mice and investigate the underlying mechanism. Methods ApoE −/− mice were fed with HFD companied with LPS to induce AS and RES was administrated for 20 weeks. Splenic CD4 + T cells were cultured and treated with anti-CD3/CD28 together with LPS, and RES was added. Serum lipids and the atherosclerotic areas of aortas were detected. The activation of CD4 + T cells were investigated both in vivo and in vitro and the expression of DNA methyltransferases (Dnmt) in CD4 + T cells were measured. Results In vivo, administration of RES prevented HFD and LPS induced dysfunction of serum lipids including TC (total cholesterol), TG (triglyceride), LDL-C (low density lipoprotein cholesterol) and HDL-C (high density lipoprotein cholesterol), ameliorated the thickened coronary artery wall and decreased the areas of atherosclerotic lesion on aortas. Besides, RES decreased the number of CD4 + T cells in peripheral blood, decreased the expression of CD25 and CD44, but not affected the expression of L-selectin (CD62L). In vitro, RES decreased the expression of Ki67, CD25 and CD44 in CD4 + T cells. Moreover, RES increased the secretion of IL-2, IL-10 and TGF-β1, decreased IL-6. In addition, RES decreased both the mRNA and protein level of Dnmt1 and Dnmt3b in CD4 + T cells. Conclusion These results indicated that RES ameliorated AS induced by HFD companied with LPS in ApoE −/− mice, inhibited the proliferation and activation of CD4 + T cells and regulated the expression of Dnmt1 and Dnmt3b.

试验旨在研究陕西三个不同地区不同泌乳时期的关中奶山羊乳常规营养成分的差异.选取健康,产奶量、体重及胎次接近的高产关中奶山羊139只(分别为凤翔县46只,淳化县50只,白水县43只)为研究对象,测定其乳脂率、乳蛋白、干物质、非脂固形物及乳糖的含量,从而对不同地区和不同泌乳时期山羊乳常规营养成分的相对含量进行对比.结果表明:3个地区奶山羊乳中乳脂率、乳蛋白、干物质和非脂固形物的含量差异不显著(P＞0.05).随着泌乳时间的延长,各地区奶山羊乳中乳脂率、乳蛋白、干物质、非脂固形物均呈现出先下降后上升的趋势;乳中乳糖含量则随着泌乳时间的增加而呈现下降的趋势.这些结果对于统一不同地区羊奶的收购提供了一定的理论依据.

Dairy goats serve as an important source of milk and also fulfill agricultural and economic roles in developing countries. Understanding the genetic background of goat mammary gland is important for research on the regulatory mechanisms controlling tissue function and the synthesis of milk components. We collected tissue at four different stages of goat mammary gland development and generated approximately 25 GB of data from Illumina de novo RNA sequencing. The combined reads were assembled into 51,361 unigenes, and approximately 60.07 % of the unigenes had homology to other proteins in the NCBI non-redundant protein database (NR). Functional classification through eukaryotic Ortholog Groups of Protein (KOG), gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that the unigenes from goat mammary glands are involved in a wide range of biological processes and metabolic pathways, including lipid metabolism and lactose metabolism. The results of qPCR revealed that genes encoding FABP3, FASN, SCD, PLIN2, whey proteins (LALBA and BLG), and caseins (CSN1S1, CSN1S2, CSN2 and CSN3) at 100 and 310 days postpartum increased significantly compared with the non-lactating period. In addition to their role in lipid and protein synthesis, the higher expression at 310 days postpartum could contribute to mammary cell turnover during pregnancy. In conclusion, this is the first study to characterize the complete transcriptome of goat mammary glands and constitutes a comprehensive genomic resource available for further studies of ruminant lactation.

Short-chain fatty acids (SCFAs) are the major energy sources for ruminants and are known to regulate various physiological functions in other species. However, their roles in ruminant milk fat metabolism are still unclear. In this study, goat mammary gland epithelial cells (GMECs) were treated with 3 mmol/L acetate, propionate or butyrate for 24 h to assess their effects on lipogenesis. Data revealed that the content of triacylglycerol (TAG) and lipid droplet formation were significantly stimulated by propionate and butyrate. The expression of FABP3, SCD1, PPARG, SREBP1, DGAT1, AGPAT6 and ADRP were upregulated by propionate and butyrate treatment. In contrast, the messenger RNA (mRNA) expression of FASN and LXRα was not affected by propionate, but reduced by butyrate. Acetate had no obvious effect on the content of TAG and lipid droplets but increased the mRNA expression of SCD1 and FABP3 in GMECs. Additionally, it was observed that propionate significantly increased the relative content of mono-unsaturated fatty acids (C18:1 and C16:1) at the expense of decreased saturated fatty acids (C16:0 and C18:0). Butyrate and acetate had no significant effect on fatty acid composition. Overall, the results from this work help enhance our understanding of the regulatory role of SCFAs on goat mammary cell lipid metabolism.

Fatty acid synthase (FASN) is a central enzyme of milk fat synthesis in the ruminant mammary gland. However, the mechanisms regulating goat FASN transcription remain elusive. The objective of this study was to investigate the mechanisms by which liver X receptor α (LXRα) regulates the FASN promoter in goat mammary epithelial cells (GMECs). In this study, T0901317 (T09), an agonist for LXRα, significantly enhanced the mRNA expression and promoter activity of FASN. Cloning of the dairy goat FASN promoter revealed the presence of one LXR response element (LXRE) and two sterol regulatory elements (SREs). Deletion or mutation of the FASN promoter LXRE reduced, but did not eliminate the transcriptional response of FASN to T09. While the LXRE and the SREs were both disrupted, basal transcription was severely reduced and there was no response to T09 treatment. This suggested that a complete response required one LXRE and two SREs. Knockdown of LXRα by siRNA did not alter the basal or T09-induced transcriptional activity of FASN. However, when sterol regulatory binding protein 1 (SREBP1) was knocked down, T09 significantly increased FASN transcription by wild-type GMECs, but had no effect on cells with LXRE-mutant promoters. The results suggested that LXR regulates FASN promoter activity through direct interaction with the LXRE as well as through increasing SREBP1 abundance. The present study provides insight into the transcriptional regulatory mechanisms controlling de novo fatty acid synthesis in GMECs.

Fat metabolism is a complicated process regulated by a series of factors. microRNAs (miRNAs) are a class of negative regulator of proteins and play crucial roles in many biological processes; including fat metabolism. Although there have been some researches indicating that miRNAs could influence the milk fat metabolism through targeting some factors, little is known about the effect of miRNAs on goat milk fat metabolism. Here we utilized an improved miRNA detection assay, S-Poly-(T), to profile the expression of miRNAs in the goat mammary gland in different periods, and found that miR-130b was abundantly and differentially expressed in goat mammary gland. Additionally, overexpressing miR-130b impaired adipogenesis while inhibiting miR-130b enhanced adipogenesis in goat mammary epithelial cells. Utilizing 3’-UTR assay and Western Blot analusis, the protein peroxisome proliferator-activated receptor coactivator-1α (PGC1α), a major regulator of fat metabolism, was demonstrated to be a potential target of miR-130b. Interestingly, miR-130b potently repressed PGC1α expression by targeting both the PGC1α mRNA coding and 3’ untranslated regions. These findings have some insight of miR-130b in mediating adipocyte differentiation by repressing PGC1α expression and this contributes to further understanding about the functional significance of miRNAs in milk fat synthesis.

Fatty acid synthase (FASN) is the central enzyme of the de novo fatty acid biosynthesis pathway. Although the FASN transcriptional regulatory mechanism has been elucidated clearly in many tumor cells, its mechanism is still not clear in the ruminant mammary gland. In this study, we cloned and sequenced a 1.8-kb fragment of the FASN 5' flanking region from goat genomic DNA. Multiple alignment analysis demonstrated that the entire 1.8-kb fragment has little homology but that the sub-section nearest the transcriptional start site (-203 to +1) is more conserved across species, in particular the binding motifs for transcriptional regulation. Deletion analysis revealed a putative core promoter region located in -297/-14 bp upstream of the transcription site within the high homology domain. Mutations of sterol response elements (SRE1 and SRE2) and the nuclear factor Y (NF-Y) binding site appeared to significantly down-regulate the FASN promoter activity in goat mammary epithelial cells (P<0.05). Further analysis showed that both SRE sites responded to sterol regulatory element-binding protein 1 (SREBP-1). SREBP-1 overexpression and knockdown by small interference RNA influenced the abundance of endogenous FASN. These data suggested that SREBP-1 may regulate FASN expression at the transcriptional level in the lactating goat mammary gland. Hence, the current work will contribute valuable information to understanding the molecular regulatory mechanisms of FASN during lactation.

Specificity protein 1 (SP1) is a ubiquitous transcription factor that plays an important role in controlling gene expression. Although important in mediating the function of various hormones, the role of SP1 in regulating milk fat formation remains unknown. To investigate the sequence and expression information, as well as its role in modulating lipid metabolism, we cloned SP1 gene from mammary gland of Xinong Saanen dairy goat. The full-length cDNA of the SP1 gene is 4376 bp including 103 bp of 5'UTR, 2358 bp of ORF (HM_236311) and 1915 bp of 3'UTR, which is predicted to encode a 786 amino acids polypeptide. Phylogenetic tree analysis showed that goat SP1 has the closest relationship with sheep, followed by bovines (bos taurus, odobenus and ceratotherium), pig, primates (pongo, gorilla, macaca and papio) and murine (rattus and mus), while the furthest relationship was with canis and otolemur. Expression was predominant in the lungs, small intestine, muscle, spleen, mammary gland and subcutaneous fat. There were no significant expression level differences between the mammary gland tissues collected at lactation and dry-off period. Overexpression of SP1 in goat mammary epithelial cells (GMECs) led to higher mRNA expression level of peroxisome proliferator-activated receptor-γ (PPARγ) and lower liver X receptor α (LXRα) mRNA level, both of which were crucial in regulating fatty acid metabolism, and correspondingly altered the expression of their downstream genes in GMECs. These results were further enhanced by the silencing of SP1. These findings suggest that SP1 may play an important role in fatty acid metabolism.

Adipose triglyceride lipase (ATGL) catalyzes the initial step in the lipid lipolysis process, hydrolyzing triglyceride (TG) to produce diacylglycerol (DG) and free fatty acids (FFA). In addition, ATGL regulates lipid storage and release in adipocyte cells. However, its role in mammary gland tissue remains unclear. To assess the role of the ATGL gene in the goat mammary gland, this study analyzed the tissue distribution and expression of key genes together with lipid accumulation after knockdown of the ATGL gene. The mRNA of ATGL was highly expressed in subcutaneous adipose tissue, the lung and the mammary gland with a significant increase in expression during the lactation period compared with the dry period of the mammary gland. Knockdown of the ATGL gene in goat mammary epithelial cells (GMECs) using siRNA resulted in a significant decrease in both ATGL mRNA and protein levels. Silencing of the ATGL gene markedly increased lipid droplet accumulation and intracellular TG concentration (P < 0.05), while it reduced FFA levels in GMECs (P < 0.05). Additionally, the expression of HSL for lipolysis, FABP3 for fatty acid transport, PPARα for fatty acid oxidation, ADFP, BTN1A1, and XDH for milk fat formation and secretion was down-regulated (P < 0.05) after knockdown of the ATGL gene, with increased expression of CD36 for fatty acid uptake (P < 0.05). In conclusion, these data suggest that the ATGL gene plays an important role in triglyceride lipolysis in GMECs and provides the first experimental evidence that ATGL may be involved in lipid metabolism during lactation.

GPR43是G蛋白偶联受体(G protein-coupled receptors,GPCRs)家族成员之一,在脂代谢中具有潜在的调控作用.本实验旨在克隆奶山羊(Capra hircus)短链脂肪酸受体基因GPR43编码区(coding sequence,CDS)并分析其组织表达谱.根据GenBank上己登录的牛(Bos taurus)GPR43基因(NM001163784)序列设计引物,利用RT-PCR方法克隆奶山羊GPR43基因的编码区(coding sequence,CDS)(GenBank登录号:HM623658),测序结果分析表明,该基因CDS区长度为987 bp,共编码329个氨基酸.序列同源性分析表明,奶山羊GPR43的核苷酸和氨基酸序列与牛、人(Homo sapiens)、鼠(Mus musculus)的相似性较高,且与牛的相似性高达90％以上.蛋白结构预测发现,奶山羊GPR43蛋白具有7个跨膜螺旋,且C端存在较强的疏水区域,N端则表现出较强的亲水性.实时定量PCR分析表明,在干奶期奶山羊的10个组织中,GPR43基因在脾脏中表达量最高,小肠、肝脏、脂肪次之,肺脏、肌肉和肾脏表达相对最少,而乳腺中也有少量的表达,表明其具有明显的组织表达特异性.泌乳期奶山羊GPR43基因的表达显著高于干奶期,表明该基因在奶山羊泌乳组织中具有一定的调控作用.研究结果为进一步揭示GPR43在奶山羊乳腺组织的功能提供参考资料.

超长链脂肪酸延伸酶6（elongase of very long chain fatty acids 6,ELOVL6）是长链脂肪酸延长反应的限速酶。本研究旨在通过对奶山羊（Capra hircus）ELOVL6基因的克隆、组织表达分析以及腺病毒（Adenovirus）介导的超表达技术,研究该基因超表达后对乳腺上皮细胞中脂肪酸代谢相关基因的影响。利用RT-PCR技术克隆了奶山羊ELOVL6基因的CDS区;利用实时荧光定量PCR（qRT-PCR）检测该基因在泌乳期奶山羊10个组织中的相对表达量;构建该基因的重组腺病毒超表达载体,包装出高滴度的腺病毒并感染奶山羊原代乳腺上皮细胞,qRT-PCR检测ELOVL6超表达效果及其对脂肪酸代谢相关基因的影响。结果表明,ELOVL6基因CDS区序列长度为795 bp（GenBank登录号:KF667508）,共编码264个氨基酸。同源分析发现,奶山羊ELOVL6基因CDS区核酸序列与牛（Bos taurus）、大鼠（Rattus norvegicus）和人（Homo sapiens）的同源性分别为97%、90%和93%,氨基酸序列同源性分别为99%、92%、95%。利用TMpred对ELOVL6蛋白跨膜结构预测分析,发现该蛋白有5个跨膜区,保守的组氨酸模体（HXXHH）位于ELOVL6蛋白的第二与第三跨膜螺旋间。ELOVL6蛋白质疏水性预测显示,该蛋白总体具有较强的疏水性。组织表达分析显示,ELOVL6基因在脂肪组织中表达量最高（P＜0.01）,小肠次之（P＜0.01）,心脏中表达量最低。超表达ELOVL6基因的重组腺病毒的滴度为108U/mL,病毒液感染原代乳腺上皮细胞48 h后,ELOVL6基因的表达量上升约200倍;脂肪酸代谢相关基因检测分析发现,固醇调节元件结合蛋白-1基因（SREBP-1）的表达量显著下降（P＜0.05）,脂肪分化相关蛋白基因（ADRP）的表达量显著升高（P＜0.05）,过氧化物酶体增殖物激活受体γ基因（PPARγ）及脂肪酸转位酶基因（CD36）的表达量无明显变化。研究结果表明,ELOVL6基因可以影响奶山羊乳腺上皮细胞脂肪酸代谢相关基因的表达,对乳腺脂肪酸代谢具有一定的调控作用。本研究为ELOVL6基因在奶山羊乳腺脂肪酸代谢调控中的功能研究提供研究依据。

【Objective】The objectives of this experiment were to clone insulin-induced gene 1(INSIG1)sequence of Saanen Dairy Goat from Northwest AF University,and to analyze the sequence characterization and quantitative tissues expression.【Method】The coding sequence region was cloned from goats mammary gland total RNA by PCR reaction with primers designed based on bovine INSIG-1,and sequence characterization was performed by biology information analyzing software.INSIG-1 gene expression patterns in ten tissues(subcutaneous fat,muscles,mammary gland,liver,kidney,heart,lung,spleen,rumen and small intestine)were conducted using real-time fluorescence quantitative PCR(RT-qPCR).【Result】The experiment obtained a 1 014bp sequence(GenBank,accession number JQ665439),which contained a coding sequence region of 831bp and 276 amino acids with molecular weight of 29.70ku and pI of 8.99.The genetic distance analysis showed that goat had the closest relationship with bovine(Bos taurus).Nucleotides and amino acid sequences alignment showed both the nucleotides and amino acid of goat INSIG-1 had the highest similarity score(97%and 90%,respectively) with bovine in GenBank.Protein structure analysis of goat INSIG-1 protein showed that INSIG-1 contained five transmembranehelices and hydrophobicity analysis showed that the protein was hydrophilic.INSIG-1 expression patterns were examined by RT-qPCR,and the results showed that the liver had the highest expression level,followed by fat,and mammary gland while heart had the lowest expression level.【Conclusion】This study cloned originally INSIG-1 gene coding sequence region of Saanen Dairy Goat from Northwest AF University,and found the gene expression patterns.

To explore the function of PPAR γ in the goat mammary gland, we cloned the whole cDNA of the PPAR γ gene. Homology alignments revealed that the goat PPAR γ gene is conserved among goat, bovine, mouse, and human. Luciferase assays revealed that rosiglitazone enhanced the activity of the PPAR γ response element (PPRE) in goat mammary epithelial cells (GMECs). After rosiglitazone (ROSI) treatment of GMECs, there was a significant (P < 0.05) increase in the expression of genes related to triacylglycerol synthesis and secretion: LPL, FASN, ACACA, PLIN3, FABP3, PLIN2, PNPLA2, NR1H3, SREBF1, and SCD. The decreases in expression observed after knockdown of PPAR γ relative to the control group (Ad-NC) averaged 65%, 52%, 67%, 55%, 65%, 58%, 85%, 43%, 50%, and 24% for SCD, DGAT1, AGPAT6, SREBF1, ACACA, FASN, FABP3, SCAP, ATGL, and PLIN3, respectively. These results provide direct evidence that PPAR γ plays a crucial role in regulating the triacylglycerol synthesis and secretion in goat mammary cells and underscore the functional importance of PPAR γ in mammary gland tissue during lactation.

Peroxisome proliferator activated receptor γ(PPARγ) plays an important role in the metabolism process of fat and glucose. In order to explore the function of PPARγ gene during lacation in dairy goat(Cap ra hircus),the experiments were designed to clone the whole cDNA of PPARγ gene by RT-PCR and RACE from Xinong Saanen dairy goat mammary gland,to analyze its expression in ten tissues and mammary tissue in different lactation periods and to detect the expressions of fatty acid metabolism related genes in mammary epithelial cell treated with rosiglitazone(ROSI) by qRT-PCR. The whole cDNA sequence of PPARγ gene was isolated from the dairy goat(GenBank accession NO.HQ589347). Homology alignments revealed that PPARγgene was conservative among the mammalian. Structure prediction showed that there were two zinc finger structures and a ligand binding domain in the dairy goat PPARγ protein. Tissue spectral analysis showed that PPARγ gene had the most abundant expression in adipose tissue,followed by the rumen and the minimal expression was detected in muscle. Expression analysis in the two different lactation periods of mammary tissue revealed that the PPARγ mRNA level during lactation peak was about twice than that of dry period. After treatment with rosiglitazone,a specific agonist,in goat mammary epithelial cells,some fatty acid related genes such as LPL(lipoprotein lipase),FABP3(fatty acid binding protein),ADRP(adipose differentiation related protein) and TIP47(tail-interacting protein 47) were up-regulated significantly. These results indicate that the PPARγ gene may play an important role in fatty acid metabolism during the dairy goat lactation process,and provide the basic data for further research in regulating milk fat,improving the quality of milk and developing mammary gland bioreactor in the individual level.