Fig. 5: Characterization of SC-alpha cells.

Pre-alpha (a, c, e, g and i) and SC-alpha cells (b, d, f, h, and j) stained for PC1 (a and b), PC2 (c and d), IRX1 (e and f), PDX1 (g and h), and NKX6.1 (i and j). Scale bar for a−j = 200 μm. The ultrastructure and granule morphology of human cadaveric alpha cells (k) and SC-alpha cells (l) as assessed by electron microscopy are similar. Arrows indicate granules; dashed line denotes the cell boundary. Inlay shows granule morphology. Scale bar for k and l = 500 nm. m SC-alpha cells secrete glucagon in response to glucose and are inhibited by somatostatin (SST). SC-alpha cell response to the glucagon secretagogue veratridine. Data are presented as mean ± SEM, significance calculated using a paired ratio Student’s t test (n = 3 biologically independent samples). n Representative electrophysiology recording of primary human alpha cell showing electrical activity in response to low (1 mM) and high (10 mM) glucose. Amplitude differences at low and high glucose are shown in the inlay (representative; n = 5 biologically independent cells). o Representative electrophysiology recording of SC-alpha cell showing electrical activity in response to low (1 mM) and high (11 mM) glucose. Amplitude differences at low and high glucose are shown in the inlay (representative; n = 30 biologically independent cells).