Exogenous Oncostatin M Induces Cardiac Dysfunction, Muscluloskeletal Atrophy and Fibrosis

Musculoskeletal diseases such as muscular dystrophy, cachexia, osteoarthritis, and rheumatoid arthritis impair overall physical health. Patients suffer from increased pain and death rate, decreased productivity and function. Inflammation and fibrosis are commonly observed in musculoskeletal disorders either at the bone, muscle, or joint. The Interleukin-6 Family of Cytokines primarily Interleukin-6 (IL-6) are implicated in the context of musculoskeletal disorders. In this study, we utilized adeno-associated virus expressing murine Oncostatin M or an empty vector at 10^11 viral particles to observe effects in muscle and bone of mice in the presence and absence of Interleukin-6. We performed echocardiography, microCT, quantitative polymerase chain reaction, histology, and RNA-sequencing to characterize the functional effects on muscle and bone. The echocardiography results demonstrated cardiac dysfunction as shown by reduced ejection fraction (%) and fractional shortening (%) with AAV-Osm compared to AAV-Null. RNA-sequencing results on cardiac muscle showed increased cardiac inflammation and fibrosis genes with AAV-Osm. Skeletal muscle weights and histology revealed muscle atrophy and fibrosis in the gastrocnemius, tibialis anterior, and quadriceps of the local limbs injected with AAV-Osm, but not observed in the non-injected side. MicroCT results revealed local and distant trabecular bone loss with AAV-Osm as shown by reduced bone volume, number, thickness, and increased trabeculae separation. Our findings show that Oncostatin M induces cardiac dysfunction, muscle, and bone atrophy independent of Interleukin-6. 10-week old wildtype mice were infected with an intramuscular injection of 10^11 viral particles of AAV-Osm and 10-week old wildtype mice were infected with an intramuscular injection of 10^11 viral particals of AAV-Null. After 12 weeks, the mice were euthanized and the cardiac muscle was isolated. The apex of the heart was used for RNA isolation and five samples from each group (AAV-Null or AAV-Osm) were submitted to the core facility. A total of nine samples were used from data analysis.