| First Author | Kubota A | Year | 2019 |
| Journal | Hum Mol Genet | Volume | 28 |
| Issue | 2 | Pages | 209-219 |
| PubMed ID | 30260394 | Mgi Jnum | J:266857 |
| Mgi Id | MGI:6257995 | Doi | 10.1093/hmg/ddy299 |
| Citation | Kubota A, et al. (2018) Cardiomyopathy and altered integrin-actin signaling in Fhl1 mutant female mice. Hum Mol Genet |
| abstractText | X-linked scapuloperoneal myopathy (X-SM), one of FHL1 (Four-and-a half LIM 1) related diseases, is an adult-onset slowly progressive myopathy, often associated with cardiomyopathy. We previously generated a knock-in mouse model that has the same mutation (c.365 G>C, p.W122S) as human X-SM patients. Mutant male mice developed late-onset slowly progressive myopathy without cardiomyopathy. In this study, we observed that heterozygous and homozygous female mice did not show alterations of skeletal muscle function or histology. In contrast, 20 month-old mutant female mice showed signs of cardiomyopathy on echocardiograms with increased systolic diameter (wild-type[WT]: 2.74+/-0.22 mm, mean+/-SD; heterozygous: 3.13+/-0.11 mm, P<0.01; homozygous: 3.08+/-0.37 mm, P<0.05) and lower fractional shortening (WT: 31.1+/-4.4%, mean+/-SD; heterozygous: 22.7+/-2.5%, P<0.01; homozygous: 22.4+/-6.9%, P<0.01). Histological analysis of cardiac muscle revealed frequent extraordinarily large rectangular nuclei in mutant female mice that were also observed in human cardiac muscle from X-SM patients. Western blot demonstrated decreased Fhl1 protein levels in cardiac muscle, but not in skeletal muscle, of homozygous mutant female mice. Proteomic analysis of cardiac muscle from 20 month-old homozygous mutant female mice indicated abnormalities of the integrin signaling pathway (ISP) in association with cardiac dysfunction. ISP dysregulation was further supported by altered levels of a subunit of the ISP downstream effectors Arpc1a in Fhl1 mutant mice and ARPC1A in X-SM patient muscles. This study reveals the first mouse model of FHL1-related cardiomyopathy and implicates ISP dysregulation in the pathogenesis of FHL1 myopathy. |
