乳腺中脂肪细胞的转化和更迭

雌性动物的乳腺组织是由胚胎时期的外胚层发育而来,出生时只有少量导管和皮下基质结构,而后在性成熟、妊娠和泌乳期乳腺发育达到峰值,这一特点使乳腺成为出生后唯一可以重复再生的器官。在乳腺发育到退化的循环中,乳腺的上皮细胞、基质白色脂肪细胞、棕色脂肪细胞和肌上皮细胞经历了一系列转化和更迭,脂肪细胞的动态转化反映了乳腺的功能变化。研究乳腺细胞的转化和更迭与母畜的泌乳直接相关,对延续母畜的生产效率有重要意义。本文就乳腺中脂肪细胞转化方面的最新研究进展进行综述,为深度揭示乳腺发育过程中细胞更迭的机制提供前沿研究信息。     

白藜芦醇通过激活去乙酰化酶1/腺苷一磷酸激活的蛋白激酶信号通路影响牛脂肪细胞凋亡

本试验旨在研究植物提取物白藜芦醇(RES)对牛皮下脂肪细胞凋亡率以及去乙酰化酶1(SIRT1)/腺苷一磷酸激活的蛋白激酶(AMPK)信号通路关键因子的mRNA和蛋白质表达量的影响。选取18月龄鲁西黄牛的皮下前体脂肪细胞,在细胞分化的第0天,更换为RES浓度分别为0(对照)、100、200和400μmol/L的培养液处理48 h,每组设3个重复。应用Hoechst33342染色检测细胞凋亡的形态学变化,流式细胞分析仪检测细胞凋亡率,荧光定量PCR(q PCR)和免疫印迹试验(Western-blot)分别检测SIRT1/AMPK信号通路上的关键因子SIRT1、A MPKα、叉头转录因子1(Fox O1)、B细胞淋巴瘤/白血病-2(Bcl-2)、半胱氨酸天冬氨酸蛋白酶-3(caspase-3)、促凋亡蛋白Bcl-2相关X蛋白(Bax)的mRNA和蛋白质表达量,并利用油红O染色鉴定脂肪细胞。结果表明,与对照组相比:不同浓度RES处理后的牛皮下脂肪细胞凋亡率均极显著增高(P0.01);不同浓度RES处理后的SIRT1、AMPKα、caspase-3、Bax的mRNA表达量均显著或极显著提高(P0.05或P0.01),Bcl-2的mRNA表达量极显著降低(P0.01);不同浓度RES处理后的SIRT1、AMPKα、caspase-3的蛋白质表达量均显著或极显著提高(P0.05或P0.01);200和400μmol/L RES处理后,Fox O1的mRNA和蛋白质表达量显著或极显著提高(P0.05或P0.01),Bax的蛋白质表达量极显著提高(P0.01),Bcl-2的蛋白质表达量极显著降低(P0.01)。100μmol/L RES处理后时,Fox O1的mRNA和蛋白质表达量以及Bcl-2、Bax的蛋白质表达量均与对照组差异不显著(P0.05)。由此可见,RES通过激活SIRT1/AM PK信号通路,同时激活通路下游的Fox O1,促进了牛皮下脂肪细胞的凋亡,为通过营养调控技术降低牛皮下脂肪沉积提供了一定的理论基础。     

Effect of protein kinase C signal pathway on resistin expression in 3T3-L1 adipocytes

AIM：To investigate the effect of protein kinase C on resistin expression in 3T3-L1 adipocytes.METHODS：The differentiated 3T3-L1 adipocytes were incubated with 50 nmol/L phorbol 12-myristate 13-acetate (PMA) or 5 μmol/L Ro-31-8220 for 24 h.Expression of resistin mRNA was detected by RT-PCR and expression of resistin protein was detected by Western blotting.RESULTS：Compared with control,PMA increased the expression of resistin mRNA and protein in 3T3-L1 adipocytes significantly (P<0.01),while Ro-31-8220 decreased the expression of resistin mRNA and protein in 3T3-L1 adipocytes obviously (P<0.01).CONCLUSION：Protein kinase C signal pathway may regulate resistin expression in 3T3-L1 adipocytes.     

小尾寒羊前体脂肪细胞分化过程相关基因表达规律的研究

为了探究小尾寒羊脂肪细胞分化过程中相关基因的变化规律,试验采集2月龄小尾寒羊腹股沟白色脂肪组织,通过酶消化法体外分离小尾寒羊前体脂肪细胞。培养前体脂肪细胞布满细胞板后,分别用诱导Ⅰ液、诱导Ⅱ液对细胞进行诱导分化,使其成为成熟的脂肪细胞。利用油红O染色法验证成熟脂肪细胞并检测脂滴含量。分别在增殖期细胞增殖70%、90%及分化期诱导Ⅰ液处理48 h、诱导Ⅱ液处理48 h、完全培养液处理48 h时（2、4、6、8、10 d）提取细胞总RNA,反转录成cDNA。采用实时荧光定量PCR检测PPARγ、C/EBPα、LPL、SREBP1、KLF5、KLF6、FABP4、STAT5、ACSS2、IGF1、ADD1、FOXO1、ACACA、DGAT1、CPT1A基因的表达规律。结果表明,试验成功分离并诱导前体脂肪细胞变为成熟的脂肪细胞,细胞内部具有明显脂滴;实时荧光定量PCR结果表明,上述基因在细胞分化阶段具有明显波动,峰值出现的时间均不相同;C/EBPα、FOXO1基因表达峰值出现在第6天,可能在细胞分化早期发挥作用;PPARγ、LPL、SREBP1、KLF5、KLF6、FABP4、STAT5、ADD1、ACSS2基因表达峰值出现在第8天,但表达倍数与趋势均不相同;ACACA基因表达量出现上下波动;IGF1、DGAT1基因表达峰值出现在第10天;CPT1A基因表达量则一直下降;FABP4基因表达倍数显著高于其他基因。本研究全面检测了小尾寒羊前体脂肪细胞在分化过程中关键基因的表达规律,可为探究小尾寒羊脂肪分化过程分子机制、挖掘参与脂肪分化新的关键基因、提高小尾寒羊肌间脂肪含量等研究提供一定的理论参考。     

单细胞转录组测序技术及其在肌内脂肪细胞研究中的应用

单细胞转录组测序(single-cell RNA sequencing, scRNA-seq)技术在单细胞水平对转录组进行测序,可从表达量、细胞量及细胞组成等多种角度描述样本,主要包括单细胞分离、mRNA反转录、文库构建、转录组测序和数据分析等步骤。单细胞分离是scRNA-seq技术操作的第一步,常用的细胞分离方法有连续稀释法、显微操作法、荧光激活流式细胞术、激光捕获显微切割术和微流控技术。基于不同细胞捕获、cDNA扩增和文库构建开发了许多scRNA-seq方法,如CEL-seq2、Drop-seq、MARS-seq、SCRB-seq、Smart-seq、Smart-seq2等。与传统测序方法相比,scRNA-seq可识别单个细胞的基因表达信息、记录细胞的空间位置、跟踪不同细胞谱系在分化过程中的轨迹,这为研究难以大量提取的肌内脂肪细胞分子特异性和发生分化过程带来极大便利。作者简要介绍了scRNA-seq技术的关键步骤,比较分析了单细胞分离和转录组测序方法的优缺点,综述了肌内脂肪细胞的起源以及scRNA-seq在肌内脂肪细胞的亚群和标记基因鉴定以及细胞分化轨迹追踪中的应用,以期为肌内脂肪...     

Lipomatosis of axillary lymph nodes in a cynomolgus monkey (Macaca fascicularis)

Lipomatosis of lymph nodes is defined as the replacement of the lymphatic parenchyma by adipose tissue which grows in the node from the hilus toward the cortical zone. In humans, it is considered as part of the normal aging process and is common in obese patients, but there are no reports in non-human primates. In this report, we describe the first case of lymph node lipomatosis in the bilateral axillary lymph nodes of a young adult cynomolgus monkey. Macroscopically, there were no apparent abnormalities in the axillary lymph nodes on either side, and their volumes were unchanged. At the cut surface, pale yellow fat-like tissue was observed in the medullary area. Histopathologically, well differentiated adipocytes replaced a large part of the lymphatic parenchyma in the area from the hilus to the medulla without any malignant findings. Based on these findings, the patient was diagnosed with lipomatosis of the lymph nodes.     

DHA对脂肪细胞周期及COX-2 mRNA表达的调节

以大鼠前体脂肪细胞原代单层培养为模型，分别以0(对照组)、40(低剂量组)和160 μmol/L(高剂量组)的二十二碳六烯酸(DHA)处理未分化的前体脂肪细胞(培养第1天)和分化的脂肪细胞(分化第1天)。采用流式细胞仪(FCM)检测细胞周期分布；逆转录-聚合酶链反应(RT-PCR)分析环氧合酶-2(COX-2 )mRNA表达情况，探讨DHA对脂肪细胞周期及基因表达的调节作用。结果显示，未分化的前体脂肪细胞经DHA作用48 h，各处理组前体脂肪细胞G1期百分比均呈上升趋势，但与对照无显著性差异；分化的脂肪细胞经DHA作用24 h，40 μmol/L组细胞内COX-2 mRNA的表达量显著下降，而160 μmol/L组则显著增加。以上结果表明，DHA对大鼠前体脂肪周期无明显的调节作用，而对脂肪细胞内COX-2 mRNA的调节具有明显的浓度依赖效应。     

CTRP3 increased insulin sensitivity of insulin resistant 3T3-L1 adipocytes via decreasing expression of inflammatory factors

AIM:To investigate the effects of C1q/TNF related protein 3 (CTRP3) on the insulin sensitivity of insulin resistant 3T3-L1 adipocytes. METHODS:The insulin resistance model of 3T3-L1 adipocytes was induced by palmic acid cultivation. The adipocytes were treated with different concentrations of recombinant CTRP3 protein (10, 50, 250,1 250 μg/L) for 12 h, and for different times (2, 6, 12, 24 h) at the concentration of 250 μg/L. The glucose consumption was detected by the glucose oxidase method. The glucose transport ratio was measured by 2-deoxidation-［3H］-glucose intake method. The contents of TNF-α and IL-6 in the supernatant were detected by ELISA. The mRNA expression of TNF-α, IL-6 and glucose transporter-4 (GLUT-4) was measured by real-time PCR. The protein expression of GLUT-4 was detected by Western blotting. RESULTS:Compared with normal control (NC) group, the glucose consumption and glucose intake ratio of insulin resistance (IR) group was decreased by 50.6% and 57.9%, respectively. Compared with IR group, with the increase in CTRP3 (10, 50, 250,1 250 μg/L) in intervention groups, the glucose consumptions were increased by 22.1%, 42.9%, 76.6% and 80.5%, respectively, and the glucose intake ratios were increased by 39.0%, 68.0%, 108.0% and 111.0%, respectively. With the increased duration (2, 6, 12 and 24 h) of CTRP3 treatment at the concentration of 250 μg/L, the glucose intake ratio was increased by 23.0%, 79.0%, 109.0% and 114.0%, respectively. The contents of TNF-α and IL-6 in the supernatant were decreased by 17.4% and 17.1% respectively as treated with CTRP3 at the concentration of 250 μg/L for 12 h, and the mRNA expression of TNF-α and IL-6 was decreased by 26.0% and 18.9% respectively, while the mRNA and protein expression of GLUT-4 was increased by 61.5% and 55.6% respectively. CONCLUSION: CTRP3 may increase the insulin sensitivity of insulin resistant 3T3-L1 adipocytes by down-regulating the expression of inflammatory factors, improving the insulin signal transduction and increasing the expression of GLUT-4.     

槲皮素对肉鸡脂肪细胞脂质代谢作用

文章以肉鸡脂肪细胞为模型,探讨槲皮素对过氧化物酶体增殖激活受体γ(PPARγ)调节脂质代谢作用。试验分对照组(5%培养液)、DMSO对照组(5%培养液+DMSO)、试验组1(5%培养液+10 mg.L-1槲皮素)、试验组2(5%培养液+20 mg.L-1槲皮素)、试验组3(5%培养液+40 mg.L-1槲皮素)。采用ELISA法检测脂肪细胞加槲皮素培养24、48、72 h后PPARγ、脂肪酸合成酶(FAS)、脂蛋白酯酶(LPL)、脂肪酸转运蛋白1(FATP1)、瘦素(leptin)蛋白含量,利用荧光定量PCR检测PPARγ、FAS、FATP1和LPL mRNA表达,利用酶法检测脂肪细胞甘油三酯(TG)含量。结果表明,与对照组相比,24 h,试验组3 PPARγmRNA表达显著降低(P<0.05);试验组1、2和3FATP1 mRNA表达均显著降低(P<0.05);试验组3 FAS mRNA表达显著降低(P<0.05),而试验组1和2有降低趋势(P=0.052),而试验组3 FAS蛋白含量显著降低(P<0.05);试验组2和3 TG含量均显著降低(P<0.05);试验组3leptin含量显著提高(P<0.05)。48 h,试验组3 PPARγmRNA表达显著降低(P<0.05),而试验组1和2有下降趋势(P=0.053),试验组1、2和3 PPARγ蛋白含量均显著降低(P<0.05);试验组1、2和3 LPL mRNA均显著降低(P<0.05);试验组1、2和3 FAS mRNA表达有下降趋势(P=0.05),而试验组2、3FAS蛋白含量均显著降低(P<0.05);试验组1、2和3 FATP1 mRNA表达和蛋白含量均显著降低(P<0.05);试验组1、2和3TG含量均显著降低(P<0.05);试验组1、2和3 leptin含量均显著提高(P<0.05)。72 h,试验组1、2和3 PPARγmRNA表达和蛋白含量均显著降低(P<0.05);试验组2 LPL mRNA显著降低(P<0.05);试验组3 FATP1 mRNA表达显著降低(P<0.05),而试验组1和2有下降趋势(P=0.057),试验组1、2和3 FATP1蛋白含量均显著降低(P<0.05);试验组1、2和3 FASmRNA表达均显著降低(P<0.05),而试验组3FAS蛋白含量显著降低(P<0.05);试验组1、2和3TG含量均显著降低(P<0.05);试验组1、2和3 leptin含量均显著提高(P<0.05)。综上所述,槲皮素可以抑制脂肪水解、跨膜转运和脂肪胞内沉积,从而抑制脂肪细胞脂肪合成代谢,但作用效果未见槲皮素浓度和时间依赖性。即槲皮素可抑制鸡脂肪细胞PPARγ调节脂肪合成代谢,进而减少肉鸡脂肪沉积。