Analysis Of The Differences In Cell Morphology And Fat Metabolism Between Bovine Back Subcutaneous Fat And Perirenal Fat Based On RNA-seq

Adipose tissue is a complex and highly active organ in the body,and its deposition site and deposition level play an important role in meat quality and body health.Subcutaneous fat and visceral fat have different physiological functions and metabolic pathways.To explore the biological differences between bovine back subcutaneous fat(BF)and perirenal visceral fat(PF),we used Angus and Simmental cattle(Bos taurus)as models.The differences in histomorphology and lipid accumulation between the two tissues were observed by HE staining and Oil Red O staining of back subcutaneous adipose and perirenal adipose;subsequently,transcriptome sequencing of the two adipose tissues was performed to analyze the highly expressed common genes in all tested tissues and to screen for key signaling pathways and differentially expressed genes that may lead to differences in lipid metabolism between BF and PF.The results showed that PF was found to have greater cell area and fewer cells as well as greater lipid metabolic activity than BF in both different breeds of cattle;whereas BF had greater lipid synthesis capacity.Transcriptome sequencing generated approximately 10.99 Gb of data in each library,and 23,472 genes were identified.Three genes including FABP4,ADIRF,and SCD that are related to adipose deposition were highly expressed in four tissues.There were 1,678 DEGs between BF and PF in Angus cattle and 1,955 DEGs in Simmental cattle.Gene Ontology(GO)function analysis identified several DEGs involved in metabolism.KEGG pathway analysis showed that four pathways related to fat metabolism(ECM-receptor interaction pathway,regulation of adipocyte lipolysis,PPAR signaling pathway,and glycerolipid metabolism)were significantly enriched.In the BF,seven genes such as COL1A1,COL1A2,COL3A1,COL2A1,RXRA,C1QTNF7,and MOGAT2 were up-regulated.The expression of six genes:ADRB3,ABHD5,CPT1 B,LPIN1,PTGER3 and CD36 were significantly upregulated in PF.To verify the accuracy of the transcriptome data,q RT-PCR validation was performed on five DEGs(COL1A1,COL3A1,RXRA,LPIN1 and GPAT3).The results showed that the expression patterns of the five genes in the qRT-PCR were consistent with RNA-seq,indicating that the expression levels determined by RNA-seq were reliable.This study explored the differences in cell morphology and lipid metabolism between different bovine adipose tissues;at the same time,the transcriptome maps of the two adipose tissues were constructed,and the key signaling pathways and candidate genes that may cause the differences were screened out,which provided a foundation for further experiments on the role of these genes in the regulation of adipose deposition.