(A) At 0 h PCS, little expression of gremlin-1 protein is detected in
both WT and FNcKO LCs. However, by 48 h PCS, gremlin-1 protein expression is
elevated in both WT (***P ≤ 0.001) and FNcKO LCs
(***P ≤ 0.001) although the expression is
significantly less in FNcKO LCs (**P = 0.004) compared to WT.
In contrast, gremlin-1 levels are greatly attenuated in FNcKO LCs by 5 days PCS
(***P ≤ 0.001) compared to WT whereas WT LCs
maintain the robust expression of gremlin-1 (***P ≤
0.001). Gremlin-1 (red) is merged with αSMA (green) and DNA detected by
Draq5 (blue). Scale bars: 35 μm. LC, remnant lens epithelial cells/lens
cells; C, lens capsule. All experiments had N = 3. Values are expressed as mean
± SEM. Asterisks (*) indicate statistically significant MFI between WT
and FNcKO at a PCS or between two PCS time points. (B)
Administration of exogenous gremlin-1 to FNcKO capsular bags elevates the levels
of the fibrotic proteins αSMA (*P = 0.015), tenascin C
(**P = 0.002), and collagen I (*P = 0.017)
concomitant with elevated levels of pSMAD2/3 levels (*P =
0.013) at 5 days PCS. In contrast, exogenous gremlin-1 treatment did not reduce
pSMAD1/5/8 levels in FNcKO capsular bags (P = 0.440). Collagen
I, Tenascin C, pSMAD2/3 (downstream of TGFβ signaling), pSMAD1/5/8
(downstream of BMP signaling) (red), αSMA (green) and DNA detected by
Draq5 (blue). Scale bars: 35 μm. LC, remnant lens epithelial cells/lens
cells; C, lens capsule. All experiments had N = 3. Values are expressed as mean
± SEM. Asterisks (*) indicate statistically significant MFI between WT
and/or FNcKO and/or FNcKO (gremlin-1) at 5 days PCS..