Activation of adult human pancreatic ductal and ductal progenitor-like cells requires extracellular matrix protein signaling [scRNA-seq]

Ductal progenitor-like cells are a subpopulation of ductal cells in the adult human pancreas that have the potential to contribute to regenerative medicine. However, the microenvironmental cues that regulate their activation are poorly understood. Here, we establish a 3-dimensional suspension culture system containing six defined soluble factors in which primary human ductal and ductal progenitor-like cells can survive but do not proliferate. Expansion and polarization occur when cells are provided with a low concentration (5% v/v) of Matrigel, a sarcoma cell product enriched in many extracellular matrix (ECM) proteins. Screening of ECM proteins identified that collagen IV is capable of partially recapitulating the effects of Matrigel. Inhibition of integrin α1β1, a major collagen IV receptor, negates collagen IV- and Matrigel-stimulated effects. These results demonstrate that collagen IV is a key ECM protein that stimulates the expansion and polarization of human ductal and ductal progenitor-like cells via integrin α1β1 receptor signaling. Single-cell RNA-sequencing of primary adult human pancreatic cells cultured in 3D suspension for 3 or 7 days. The cells were derived from a freshly dissociated, islet-depleted exocrine tissue that was either directly placed into culture or was first cryopreserved before culture.