Expression analysis of BMP7 responsive P2RY1/ALK3 expressing progenitor like cells within the human exocrine pancreas

Purpose: Here we demonstrate ALK3Bright/PDX1+ cells residing within the human pancreatic ducts have progenitor like characteristics. Using flow cytometery, live-cell sorting of ALK3bright/PDX1+ cells is possible using a surrogate surface marker for PDX1 (P2RY1). Treating ALK3bright/P2RY1+ cells with BMP7 results in their expansion. Later removal of BMP7 results in the differentiation of these cells to ß-like cells. Here we compare the mRNA expression profiles of these three different cell types (in triplicate). Methods: mRNA profiles of ALK3Bright/P2RY1+ cells isolated from human non-endocrine pancreatic tissue, ALK3Bright/P2RY1+ cells treated with BMP7 and ALK3Bright/P2RY1+ cells differentiated to ß-like cells after BMP7 removal were generated by deep sequencing, in triplicate, using Illumina HiSeq PE Cluster Kit v4 and Illumina HiSeq Flow Cell v4 with 50 nt paired end reads plus dual index reads using the Illumina HiSeq SBS kit v4. Sequence reads that passed quality filters were analyzed at the transcript isoform level following alignment using TopHat v2.1.0 followed by exon and gene level counting using Bioconductor easyRNASeq v 2.4.7. Conclusions: Our study represents the first detailed analysis of ALK3Bright/P2RY1+ sorted cells with biological replicates. We demonstrate ALK3Bright/P2RY1+ cells were shown to form progenitor-like epithelial colonies characterized by NKX6.1 and PDX1 expression. Unlike the negative fraction controls, these colonies responded to BMP-7 by generating new ß-like cells as well as cells from other pancreatic lineages. The transcriptional profile of these cells and their BMP7 treated counterparts suggest a mitotic and progenitor like state. Our studies confirm the progenitor-like nature of ALK3Bright/PDX1+ cells within the human pancreas and suggest a specific anatomical location within the ductal network. Overall design: Comparison of transcriptional expression in Alk3Bright/P2RY1+ cells, Alk3Bright/P2RY1+ cells treated with BMP7 and Alk3Bright/P2RY1+ cells allowed to differentiate after BMP7 removal. Human islets, isolated from the same donors were included as a control.

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Qadir MMF, Álvarez-Cubela S, Klein D, Lanzoni G, García-Santana C, Montalvo A, Pláceres-Uray F, Mazza EMC, Ricordi C, Inverardi LA, Pastori RL, Domínguez-Bendala J