Figure 5.

Real-Time Analysis and Targeting of β Cell Hubs

(A and B) Schematic showing the effects of eNpHR3.0 activation upon β cell Ca²⁺ signaling (A), and snapshot showing placement of a diffraction-limited laser spot over a discrete islet region (B) (scale bar, 25 μm; image cropped to display a single islet).

(C) Experimental flowchart for real-time manipulation of hub function.

(D–F) Representative functional connectivity map and activity plots at high glucose (11 mM), before (D), during (E) and after (F) optogenetic silencing (identified hub cell; red). A representative Ca²⁺ trace is displayed above.

(G and H) Summary data showing a reversible collapse in the proportion of correlated cell links following hub (G), but not follower (or non-hub) (H) silencing (n = 7–9 recordings from four animals).

(I–K) Representative cell-cell entrainment patterns (I) and representative Ca²⁺ rises in linked cells (J) following photopharmacological stimulation of an identified hub (red) at 3 mM glucose using JB253 (50 μM). Box and whiskers plot shows the range and mean number of hub- or follower-entrained cells under high (11 mM) glucose (High Glu) conditions, and following targeted stimulation using JB253 in the presence of control (3 mM glucose), BGA, AGA, and low (1 mM) glucose (low Glu) (K) (n = 4–7 recordings from three to four animals).

(L) Insulin secretion measured using JP-107 is unaffected following illumination of follower (or non-hub) cells or wild-type (WT) islets, but suppressed in response to hub or islet (global) shutdown (mean traces shown) (n = 8 islets from 4 animals).

Scale bars, 20 μm. Data are means ± SEM. ^∗p < 0.05. NS, non-significant. See also Figures S2 and S3 and Movies S5 and S6.