Fig. 8: Pharmacological inhibition of Irgm1 alleviates OVX-induced osteoporosis.

A The protein-protein (PPI) network of IRGM-related genes. B Network proximity analysis of the distribution of distances between drug targets and IRGM-related proteins. C Molecular docking diagram between mifamurtide and Irgm1. D Schematic of the experiment. Mice treated with mifamurtide (1 mg/kg, i.v.) or PBS one week after OVX were sacrificed at 20-week-old. E Representative 3D reconstructed CT images of the distal femur. F Quantitative measurements of BV/TV, Tb. N, Tb. Th, and Tb.Sp. All bar graphs are presented as the mean ± SD (n = 4), ^∗∗p < 0.01, ^∗∗∗p < 0.001, and ns vs the indicated groups. G CCK8 assay detected BMDMs viability with different concentrations of mifamurtide (n = 3). H TRAP staining of osteoclasts differentiated from BMDMs. BMDMs were subjected to osteoclast full differentiation induced with RANKL (40 ng/ml) and M-CSF (10 ng/ml) for 5 days under different concentrations of mifamurtide (0, 50, 5000 nM). Scale bar = 100 μm. I Quantitative analysis of TRAP-positive MNCs from (H) (n = 3). ^∗p < 0.05 and ^∗∗p < 0.01 vs the indicated group. J WB analysis of expression of Keap1, Nrf2, and Irgm1 in BMDMs induced with RANKL (40 ng/ml) and M-CSF (10 ng/ml) for 3 days, treated with different concentrations of mifamurtide (0, 50, 5000 nM). K–M Quantitative analysis of Keap1 (J), Nrf2 (K), and Irgm1 (L) from (I) were normalized to GAPDH and presented as means ± SD (n = 3). ^∗p < 0.05, ^∗∗p < 0.01 and ^∗∗∗p < 0.001 vs the indicated groups. N Schematic illustration of the role of Irgm1 in regulating the Keap1-Nrf2 signaling pathway to oppose OVX-induced osteoporosis.