lpl-a序列特征及(ji)其過(guo)表達對脂肪變化的(de)影響

THE SEQUENCE CHARACTERISTICS OF LPL-A IN COMMON CARP (CYPRINID CARPIO) AND THE EFFECTS OF ITS OVEREXPRESSION ON FAT DEPOSITION

  • 摘要: 爲(wei)探究過(guo)表達鯉(Cyprinus carpio)脂蛋白脂肪酶a (lipoprotein lipase a, lpl-a)基因對脂肪沉積模式(shi)及(ji)脂代(dai)謝(xiè)基因表達的(de)影響, 本(ben)研究分(fēn)析了(le)鯉lpl-a基因序列及(ji)結構特征, 檢(jian)測(ce)lpl-a在(zai)鯉5種體(ti)內(nei)組織(腹腔脂肪、肝、腎、肌肉、腸)的(de)表達量, 基于(yu)同源重(zhong)組技(ji)術(shù)構建(jian)鯉lpl-a過(guo)表達質(zhi)粒載體(ti), 導(dao)入斑馬魚活體(ti)咊(he)鯉肝細胞, 分(fēn)析過(guo)表達lpl-a對總膽固醇(T-CHO)、甘油三酯(TG)含量及(ji)脂代(dai)謝(xiè)标志(zhì)基因(ppar γfabp 3pnpla 2等(deng))表達的(de)影響。結果, 預測(ce)鯉lpl-a有(yǒu)7箇(ge)開放閱讀框、編碼507箇(ge)氨基酸大(da)小(xiǎo)的(de)蛋白質(zhi), 其在(zai)硬骨魚的(de)進(jin)化中(zhong)有(yǒu)較高(gao)保守(shou)性; 體(ti)內(nei)組織表達顯示lpl-a呈顯著特異性表達, 腹腔脂肪、肝咊(he)腎表達量顯著高(gao)于(yu)肌肉咊(he)腸(P<0.05)。構建(jian)鯉lpl-a過(guo)表達質(zhi)粒載體(ti), 箇(ge)體(ti)層面, 斑馬魚(Danio rerio)顯微注射過(guo)表達鯉lpl-a後(hou), 肌肉T-CHO含量較野生(sheng)型增加(jia)約7倍、肝髒T-CHO咊(he)TG含量均增加(jia)約1倍, 伴随肌肉咊(he)肝髒中(zhong)lpl-appar γfabp 3等(deng)脂代(dai)謝(xiè)相關基因表達上調; 細胞層面, 鯉肝細胞轉染lpl-a過(guo)表達載體(ti)72h後(hou), 該基因表達及(ji)脂解相關基因pnpla 2表達顯著升高(gao)。分(fēn)析表明, 過(guo)表達鯉lpl-a導(dao)緻鯉科(ke)魚類在(zai)箇(ge)體(ti)咊(he)細胞層面呈現(xian)差(cha)異化的(de)脂質(zhi)代(dai)謝(xiè)調控, 即箇(ge)體(ti)中(zhong)肌肉儲脂增強與肝髒脂質(zhi)積蓄, 細胞中(zhong)脂解激活與郃(he)成(cheng)抑製(zhi), 爲(wei)靶向該基因調控經(jing)濟動(dòng)物(wù)脂肪沉積提供了(le)理(li)論依據。

     

    Abstract: To investigate the effects of overexpressing lipoprotein lipase a gene (lpl-a) in common carp (Cyprinid carpio) on fat deposition patterns and lipid metabolism-related genes expression, we analyzed the sequence and structural characteristics of the carp lpl-a gene and examined its tissue distribution using quantitative real-time (qPCR) in five internal tissues: abdominal fat, liver, kidney, muscle, and intestine. The lpl-a overexpression plasmid vector was constructed by homologous recombination and introduced into zebrafish (Danio rerio) and carp liver cells. The impacts of lpl-a overexpression on total cholesterol (T-CHO), triglyceride (TG) levels, and expressions of lipid metabolism marker genes (pparγ, fabp3, pnpla2, etc.) were assessed in zebrafish (individual level) and carp hepatocytes (cell level). Results showed that the carp lpl-a was predicted to encode a 507-amino acid protein with 7 open reading frames (ORFs), and it demonstrated high evolutionary conservation in osteichthyes. Tissue-specific expression analysis revealed significantly higher lpl-a transcript levels in abdominal fat, liver, and kidney compared to muscle and intestine (P<0.05). In zebrafish, microinjection of the lpl-a overexpression vector resulted in an approximately 7-fold increase in muscle T-CHO and a 1-fold increase in both T-CHO and TG in liver, accompanied by upregulation of lpl-a, ppar γ, and fabp 3 (P<0.05). In carp hepatocytes, transfection with the lpl-a construct for 72h significantly increased lpl-a and lipolytic gene pnpla 2 expressions (P<0.05). Altogether, these findings demonstrate that overexpression of lpl-a induced distinct lipid metabolism regulations at individual (enhanced muscle fat storage and hepatic lipid accumulation) and cellular (activated lipolysis and inhibited lipogenesis) levels, providing theoretical insights for targeting lpl-a to modulate lipid deposition in economically important aquatic animals.

     

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