Oral Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2014

Comparative analysis of Insulin-producing cells in pancreas, gallbladder and the brain (#105)

Wilson Wong 1 , Mugdha Joglekar 1 , Sarang Satoor 1 , Subhshri Sahu 1 , Ed Stanley 2 , Andrew Elefanty , Tom Kay 3 , Thomas Loudovaris 3 , Helen Thomas 3 , Wayne Hawthorne 4 , Philip O'Connell 4 , David Martin 5 , Anandwardhan Hardikar 1
  1. NHMRC Clinical Trials Centre University of Sydney, Camperdown, NSW, Australia
  2. Murdoch Childrens Research Institute, The Royal Children’s Hospital, Parkville, VIC, Australia
  3. St. Vincent's Institute, Fitzroy, VIC, Australia
  4. National Pancreas Transplant Unit, Westmead Millennium Institute, University of Sydney at Westmead Hospital, Westmead, NSW, Australia
  5. Department of Upper Gastrointestinal Surgery, Royal Prince Alfred and Concord Hospitals, Sydney, NSW, Australia
Transplantation of pancreatic islets is a current therapy for treatment of diabetes; however it is limited by the availability of cadaveric donors and yield from islet isolations.  It is therefore important to identify alternate sources of insulin-producing cells for treatment of diabetes.  During our search for “lineage-committed” islet progenitor cells, we identified pro-insulin expression and c-peptide immuno-positive cells in rodent/human gallbladders and brain.  We are the first to identify insulin-producing cells in adult human gallbladder1. Although the level of pro-insulin transcripts in gallbladder is thousand-fold less than in pancreatic islets, this is significantly higher than the reported levels of differentiated stem cells. Insulin-producing cells have been localized in brains of fruit-fly2,3, mice4 as well as in a clinical report of insulinoma5.   We applied a range of molecular techniques including Next Generation Sequencing (NGS), TaqMan-based real-time PCR, Confocal microscopy, Flowcytometry, single cell PCR and Chromatin IP (ChIP)  to identify similarities and differences in the transcriptome, epigenome and protein expression of rodent and human islets, gallbladder and brain cells.  Our analyses using a Pdx1-GFP reporter mouse model indicates that the developing gallbladder contains comparable proportions of Pdx1 / insulin-expressing cells, which are retained in the adult gallbladder epithelium.  On the other hand, the brain shows a significant reduction in the proportion of insulin-producing cells in adult life as compared to the embryonic samples.  ChIP for H3K4me3 and H3acetylation at Pdx1 gene promoter confirmed that open chromatin conformation was retained in the adult brain.  I will discuss our findings demonstrating the similarities in transcriptome and epigenome of human and rodent gallbladder and pancreas samples, identified through NGS and single cell PCR technologies. Comparative analysis using chromosomal-conformation-capture (3C) and “loopscape” analysis of insulin promoter region in islets and gallbladder cells would identify molecules that would aid in efficient differentiation of islet progenitor cells.