Supplementary MaterialsFIGURE S1: Treatment with RK35 does not affect the amount of intranuclear aggregates: Mice were subject to a weekly regimen of either saline or the anti-myostatin RK35 antibody i
July 31, 2020
Supplementary MaterialsFIGURE S1: Treatment with RK35 does not affect the amount of intranuclear aggregates: Mice were subject to a weekly regimen of either saline or the anti-myostatin RK35 antibody i. model of OPMD at 42 weeks of age. The mice CP-673451 inhibition were administered a weekly dose of 10 mg/kg RK35 intraperitonially for 10 weeks, following which serum and histological analyses were performed on muscle samples. Results The administration of the antibody resulted in a significant decrease in serum myostatin and collagen deposition in muscles. However, minimal effects on body mass, muscle mass and myofiber diameter, or the density of intranuclear inclusions (INIs) (a hallmark of disease progression of OPMD) were observed. Conclusion This study demonstrates that inhibition of myostatin does not revert muscle atrophy in a mouse model with established OPMD disease, but is effective at CP-673451 inhibition reducing observed histological markers of fibrosis in the treated muscles. gene whose product regulates poly (A) tail length on mRNAs, controls the use of alternative polyadenylation (APA) sites, and influences pre-mRNA splicing among other roles (Harish et al., 2015). In OPMD, mutated PABPN1 has a poly-alanine CP-673451 inhibition expansion at the N terminus of the protein, resulting in 11C18 repeats instead of the normal 10 present in unaffected individuals (Brais et al., 1998; Blumen et al., 2000). The alanine expansion results in protein misfolding and consequent accumulation in the nuclei as intranuclear inclusion bodies (INI) (Harish et al., 2018). These INI bodies also sequester other molecules such as poly(A)-containing RNA, various CP-673451 inhibition transcription factors of the proteasome ubiquitin pathway (ubiquitin and 20S catalytic proteasomal subunit), molecular chaperones (HDJ-1, HSP70), heterogeneous nuclear ribonucleoprotein A1 (HNRPA1) and arginine methyltransferares (Harish et al., 2018). The sequestration of these proteins may induce defects in transcriptomic or protein folding pathways (Tavanez et al., 2009; Malerba et al., 2017). Current methods to ameliorate disease symptoms are surgical in nature, however, various small molecule and gene therapy strategies have been proposed that directly or indirectly target the INI bodies (Harish et al., 2018). Concordant with other muscular dystrophies, moderate muscle atrophy (especially in non-somitically derived muscles) has also been described in patients with OPMD (Schmitt and Krause, 1981; Little and Perl, 1982), and hence therapeutic agents that target muscle mass may ameliorate symptoms in this disease state. Myostatin is a known regulator of muscle mass and has been examined as a therapeutic target to ameliorate symptoms of dystrophy, cachexia, and sarcopenia (Rodgers and Garikipati, 2008; Sartori et al., 2013; Mouisel et al., 2014). While primary myostatin signaling CP-673451 inhibition is effected as a balance between the bone morphogenetic protein (BMP) and activing receptor IIB (ACTRIIB) signaling pathways, secondary signaling mechanisms also influence cell growth via interactions with the IGF-1, p21/Cdk, Wnt signaling pathways (Rodgers and Garikipati, 2008; McPherron, 2010; Sartori et al., 2013). Studies in myostatin null mice report an increased bone mineral density (as compared to wild-type controls) and ejection fraction, resistance to diet induced obesity, dyslipidemia, atherogenesis, hepatic steatosis and macrophage infiltration, besides hJAL a substantial improvement in muscle mass (White and LeBrasseur, 2014). Inhibition of myostatin on disease progression has been studied in aged mice (modeling Duchenne muscular dystrophy) and C57 (wildtype) model systems utilizing various strategies, and report variable levels of efficacy (LeBrasseur et al., 2009; Murphy et al., 2010; Arounleut et al., 2013). Unsurprisingly, a variety of strategies to disrupt myostatin signaling are in pre-clinical and clinical development, including but not limited to propeptide, gene therapy, gene editing, ligand traps,.