Figure 4. ‘β-cell like’ properties of α-cells from HFD-fed mice.

A-B) Glucagon (A) and insulin (B) secretion from islets of male C57/bl6N mice fed HFD for 10–12 weeks starting from 8 weeks of age (red) compared with age matched (18–20 week) chow fed controls (black). (n = 3, 3 mice).

C) Effect of the P/Q-type Ca²⁺ channel blocker agatoxin (100 nM) and the L-type Ca²⁺ channel blocker isradipine (10 μM) on total exocytosis from chow diet (CD) and HFD α-cells at 1 mM glucose (n = 34, 42, 34, 40, 29, 39 cells from 8 HFD and 8 CD mice).

D-E) Effect of the P/Q-channel activator GV-58 (10 μM) to delay Ca²⁺ current inactivation in both CD and HFD α-cells (D, n = 23, 36, 24, 23 cells from 3 CD and 3 HFD-fed mice) and on exocytosis (E) from CD (grey) and HFD (pink) α-cells at 1 and 5 mM glucose (n = 15, 16, 16, 21 cells from 3 CD mice; n = 14, 13, 15, 14 cells from 3 HFD-fed mice).

F) Steady-state voltage-dependent Na⁺ current inactivation curves (left) and individual half-inactivation voltages (right) from α-cells of chow fed and HFD mice (n = 36, 44 cells from 9 CD and 9 HFD mice, measured at 1 mM glucose). Half-inactivation voltages from fit curves are indicated.

G) From a separate set of CD and HFD α-cells assessed by patch-seq (Suppl Fig 4), mean expression (black) and % of cells expressing (blue) some α-cell identity transcription factors in CD and HFD α-cells.

H) Mean expression (black) and % of cells expressing (blue) the β-cell Na⁺ channel isoform, Scn9a, in HFD α-cells.

I) Correlation Z-scores of the negative shift in Na⁺ channel steady-state inactivation (at 1 mM glucose) in HFD α-cells with transcripts involved in α-cell lineage and identity.

*- P < 0.05; **- P < 0.01; and ***- P < 0.001 by the Student’s t-test (F), or by one-way ANOVA (D,E) or two-way ANOVA (A,B,C) followed by Tukey post-test to compare points or groups with the 5 mM glucose points (A,B), with the 1 mM glucose control group, or as indicated.