2139-P: Real-Time Monitoring and High-Resolution Analysis of Human Pancreatic Ductal Plasticity
Authors: FAHD QADIR MIRZA MUHAMMAD , ALVAREZ-CUBELA SILVIA , DIJK JASMIJN VAN , WEITZ JONATHAN , CECHIN SIRLENE , KLEIN DAGMAR , TAMAYO ALEJANDRO M. , ALMACA JOANA , CAICEDO ALEJANDRO , KUSMARTSEVA IRINA , HILLER HELMUT , BEERY MARIA , JOHNSON KEVIN B. , MORENO HERNANDEZ YAISA B. , NAVARRO RUBIO MARIA B. , SADIQ SAAD , RICORDI CAMILLO , PUGLIESE ALBERTO , FRAKER CHRISTOPHER , PASTORI RICARDO , DOMÍNGUEZ-BENDALA JUAN 
Published: June 2019

Introduction: The exocrine compartment of the pancreas has been hypothesized to harbor progenitor cells. While their existence remains the subject of debate, the widespread consensus is that any such putative progenitors should express the pancreatic-duodenal homeobox 1 protein (PDX1). Progenitor cell stimulation often depends on concurrent TGFb inhibition and BMP activation. We further hypothesized that PDX1-expressing putative b-cell progenitors may respond to BMP-7. Our data (1) indicate that extrainsular PDX1+/ALK3+ cells do so by proliferating and subsequently, upon BMP-7 withdrawal, differentiating in a multilineage fashion. Here we present additional mechanistic data on b-cell regeneration using a novel human pancreatic slice culture system that allows for the observation of pancreatic tissue for 2 weeks. We further show single cell RNAseq analyses of sorted ALK3+ from the human pancreas, confirming the heterogeneity of the ductal compartment.
Methods: HPS: Low melting point agarose-embedded, vibratome-sectioned live pancreatic slices were generated from human donors. Transduction with a CMV-[loxP]-dsRed-[loxP]-EGFP adenovirus + insulin promoter-Cre adenovirus was done in slices cultured atop optically clear perfluorcarbon (PFC)-based membranes. scRNAseq of ALK3+ sorted cells from human non-endocrine tissue (hNEPT, the leftover of islet isolations) was done on 1,000 cells/sample (250K reads/cell).
Conclusions: We report the use of live HPS as a novel tool for the study of pancreatic regeneration. Our preliminary results confirm the feasibility of tracing and monitoring discrete transitional events in response to BMP signalling stimulation, as well as the existence of multiple ductal populations at various degrees of differentiation in healthy donor pancreata.
References:
1. Qadir MMF, et al. P2RY1/ALK3-Expressing Cells within the Adult Human Exocrine Pancreas Are BMP-7 Expandable and Exhibit Progenitor-like Characteristics. Cell Reports. 2018

Disclosure
M. Qadir: None. S. Alvarez-Cubela: None. J. van Dijk: None. J. Weitz: None. S. Cechin: None. D. Klein: None. A.M. Tamayo: None. J. Almaca: None. A. Caicedo: None. I. Kusmartseva: None. H. Hiller: None. M. Beery: None. K.B. Johnson: None. Y.B. Moreno Hernandez: None. M.B. Navarro Rubio: None. S. Sadiq: None. C. Ricordi: Advisory Panel; Self; Zone Labs. A. Pugliese: None. C. Fraker: None. R. Pastori: Other Relationship; Self; Ophysio Inc. J. Domínguez-Bendala: None.

Funding
Diabetes Research Institute Foundation; Inserra Family Foundation; Fred and Mabel R. Parks Foundation; Foundation for Diabetes Research; Tonkinson Foundation; Michael J. and Katherine E. Franco Foundation; Frank Strick Foundation; Mildred Graff; National Institutes of Health (R43DK105655-01, R44DK105655-02, U01DK120393-01); Fulbright Scholarship Board/International Institute of Education (to M.M.F.Q.)