Pansteatitis Induced Differential Expression of Inflammatory and Apoptosis Genes in Adipose Tissue: A Glimpse into Pathophysiology of the Condition in the Nile Crocodile.

Abstract

In the quest to understand the pathophysiology of pansteatitis in the Nile crocodile, a condition that was attributed to the recent crocodile die off at the Olifant river, Mpumalanga, the whole transcriptome of the Nile crocodile was sequenced and assembled using whole transcriptome shotgun sequencing data by Illumina RNAseq from RNA obtained from fat body and other adipose tissues.Total RNA, from abdominal fat body and other adipose tissue from normal farmed Nile crocodiles and samples collected from Nile crocodiles that had died of pansteatitis, were extracted and purified using Qiagen RNA mini prep (Qiagen, USA). RNA samples library were prepped using the Truseq stranded total RNA sample preparation and sequenced on the Illumina Hiseq 2500 with v4 SBS chemistry. Reads were assembled using Tophat (http://tophat.cbcb.umd.edu/) and aligned with reference transcriptome from Crocodylus porosus using Cufflinks (http://cufflinks.cbcb.umd.edu/) for downstream analysis while the differential gene expression analysis was done using Cuffdiff and RSEM (http://deweylab.github.io/RSEM/).A total of 13,329 genes were identified out which 1541 genes related to inflammatory response and apoptosis were identified. A total of 641 genes were up regulated in the pansteatitis samples as compared to normal adipose tissues using a fold change of 16.0. A total of 70 inflammatory genes were up regulated in the pansteatitis samples including, PDCD5 (programmed cell death 5), NFIL3 (nuclear factor, interleukin 3 regulated protein), HSP90B1 (heat shock protein 90kDa beta (Grp94), member 1), VCAM1 (vascular cell adhesion molecule 1), IL1R1 (interleukin 1 receptor, type I), TNIP1 (TNFAIP3 interacting protein 1), JAK1 (Janus kinase 1), TNFAIP2 (tumor necrosis factor, alpha‐induced protein 2) IL6ST (interleukin 6 signal transducer (gp130, oncostatin M receptor)) CFD (complement factor D (adipsin) and PPARG (peroxisome proliferator‐activated receptor gamma) among others. These genes are responsible for inflammation, apoptosis, regulation of Toll‐like receptors in inflammatory response, leucocyte migration and fibrosis in chronic inflammation.We present for the first time in the Nile crocodile, a comprehensive lists of inflammatory response genes that are expressed and up regulated in pansteatitis in the Nile crocodile.Support or Funding InformationPart of the study was funded by Tertiary Education Trust Fund (TETFund) AST and D, Nigeria and Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.