Proteomic analysis of decellularized pancreatic matrix identifies collagen V as a critical regulator for islet organogenesis from human pluripotent stem cells

In pancreatic tissue engineering, generating human pancreatic islet organoids from stem cells has been challenging due mainly to a poor understanding of niches required for multicellular tissue self-assembly in vitro. In this study, we aimed to identify bioactive, chemically defined niches from natural, biological materials for islet development in vitro. We investigated the proteomics of decellularized rat pancreatic extracellular matrix (dpECM) hydrogel using advanced bioinformatics analysis, and identified that type V collagen (ColV) is constantly and abundantly present in dpECM hydrogel. Niches provided to human pluripotent stem cells (iPSCs) by presenting ColV in matrix coating substrates permitted stem cells progression into islet-like organoids that consist of all major pancreatic endocrine cell types, i.e. a, beta, delta, and pancreatic polypeptide cells. In the presence of ColV niches, gene expressions of all key pancreatic transcription factors and major hormone genes significantly increased in iPSC-derived organoids. Most importantly, ColV-containing microenvironment resulted in enhanced glucose responsive secretions of both insulin and glucagon hormone from organoids. The study demonstrates that ColV is a critical regulator that augments islet self-assembly from iPSCs, and it is feasible to utilize natural biomaterials to build tissue cues essential for multicellular tissue production in vitro.