Fig. 4.

MyD88 regulates myoblast fusion through non-canonical NF-κB pathway. a Primary myoblasts were prepared from hind limb muscle of WT and MyD88-KO mice. Cells were then plated at equal densities and incubated in DM. Samples were collected at various time points following addition of DM and processed for biochemical analysis. Immunoblots demonstrate the levels of p100/p52, IκBα, and unrelated protein tubulin. b Primary myoblasts prepared from WT mice were transfected with empty vector or vector containing MyD88 cDNA. After 48 h, cells were collected and protein lysates were made. Representative immunoblots demonstrating levels of MyD88, p100/p52, and unrelated protein tubulin. c WT and MyD88-KO primary myoblasts were transfected with vector alone or vector containing cDNA for p52, RelB, or IKKα. The cells were incubated in DM for 48 h and cultures were fixed and stained with anti-MyHC and DAPI. Representative photomicrographs are presented here. Scale bar: 50 µm. d Quantification of the percentage of myotubes containing ≥ 10 nuclei under each condition. e Quantitative analysis of average myotube diameter under indicated condition. For d and e, N = 5 in each group. Error bars represent s.d. *p < 0.05 from WT cultures transfected with vector alone by unpaired t-test. ^# p < 0.05 from MyD88 cultures transfected with vector alone by unpaired t-test. f Representative immunoblots presented here confirm the overexpression of p52, RelB, and IKKα proteins in transfected cultures