Heterogenous impairment of α cell function in type 2 diabetes is linked to cell maturation state

AUTHORS

Dai Xiao-Qing , Camunas-Soler Joan , Briant J BLinford , Dos Santos Theodore , Spigelman FAliya , Walker MEmily , Arrojo E Drigo Rafael , Bautista Austin , Jones CRobert , Avrahami Dana , Lyon James , Nie Aifang , Smith Nancy , Zhang Yongneng , Johnson Janyne , Manning Fox EJocelyn , Michelakis DEvangelos , Light EPeter , Kaestner HKlaus , Kim KSeung , Rorsman Patrik , Stein WRoland , Quake RStephen , MacDonald EPatrick . Cell Metab. 2022 2 1; ().

ABSTRACT

In diabetes, glucagon secretion from pancreatic α cells is dysregulated. The underlying mechanisms, and whether dysfunction occurs uniformly among cells, remain unclear. We examined α cells from human donors and mice using electrophysiological, transcriptomic, and computational approaches. Rising glucose suppresses α cell exocytosis by reducing P/Q-type Ca²⁺ channel activity, and this is disrupted in type 2 diabetes (T2D). Upon high-fat feeding of mice, α cells shift toward a “β cell-like” electrophysiological profile in concert with indications of impaired identity. In human α cells we identified links between cell membrane properties and cell surface signaling receptors, mitochondrial respiratory chain complex assembly, and cell maturation. Cell-type classification using machine learning of electrophysiology data demonstrated a heterogenous loss of “electrophysiologic identity” in α cells from donors with type 2 diabetes. Indeed, a subset of α cells with impaired exocytosis is defined by an enrichment in progenitor and lineage markers and upregulation of an immature transcriptomic phenotype, suggesting important links between α cell maturation state and dysfunction.