Fig. 8: Slc37a2 deletion impairs bone resorption but does not alter osteoclast differentiation, spreading, or RANKL-signaling cascades.

a and b WT and Slc37a2^KO BMM-derived osteoclasts were TRAP stained (a), and TRAP activity measured (405 nm) (b) (n = 3). Bar, 50 µm. c Representative images of WT and Slc37a2^KO osteoclasts immunostained for F-actin, αvβ3 (IntegriSense⁶⁴⁵) and nuclei. Bar 50 µm. d Expression of osteoclast and SL markers during RANKL-induced differentiation of WT and Slc37a2^KO BMMs by immunoblotting using indicated antibodies (n = 3). e RANKL-signaling in WT and Slc37a2^KO BMMs. Immunoblotting of the levels and phosphorylation states of ERK1/2, AKT, and IκBα in response to RANKL (n = 3). f Representative Von Kossa staining of WT and Slc37a2^KO osteoclasts on mineralized substrates (n = 3). g–m Representative images of in vitro bone resorption assays of WT and Slc37a2^KO osteoclasts using reflective microscopy, SEM, and confocal microscopy with quantification of the percentage of eroded surface (h, n = 11 bone discs from 3 experiments; P = 0.0004), pit area (i, n = 11 bone discs from 3 experiments; P = 0.0029), trench surface per bone slice (j, n = 11 bone discs from 3 experiments; P = 0.0006), trench surface/eroded surface (k, n = 11 bone discs from 3 experiments; P < 0.0001), collagen1a staining (l, n = 12 bone discs from 3 experiments; P < 0.0001) and a number of F-actin rings per bone slice (m, n = 12 bone discs from 3 experiments; P = 0.9293). Black and white arrows indicate bone resorption pits in toluidine blue and collagen 1 stained bone slices, respectively. Bars, 50 µm. n and o Rescue of Slc37a2^KO osteoclasts activity by lentiviral transduction of ^emGFP-Slc37a2. Depicted are representative images of toluidine blue stained resorptive pits of WT, Slc37a2^KO, and ^emGFP-Slc37a2 transduced Slc37a2^KO osteoclasts with quantification of the percentage resorbed surface per field quantified (n = 54 fields from 3 experiments, WT vs. Slc37a2^KO P < 0.0001; WT vs. ^emGFP-Slc37a2^KO P = 0.0011; Slc37a2^KO vs. ^emGFP-Slc37a2^KO P = 0.0250). All data are presented as means ± SD. * P < 0.05, ** P < 0.01, *** P < 0.001 by two-tailed unpaired Student’s t-test (h–m) or nested one-way ANOVA (o). Bar, 50 µm. Source data are available in the Source Data file.