Analysis of deregulated genes upon Septin9 depletion in C2C12 and primary isolated myoblasts

Controlled myogenic differentiation is integral to the development, maintenance and repair of skeletal muscle, necessitating precise regulation of myogenic progenitors and resident stem cells. The transformation of proliferative muscle progenitors into multinuclear syncytia involves intricate cellular processes driven by cytoskeletal reorganization. While actin and microtubles have been extensively studied, we illuminate the role of septins, an essential yet still often overlooked cytoskeletal component, in myoblast architecture. Notably, Septin9 emerges as a critical regulator of myoblast differentiation during the initial commitment phase. Knock-down of Septin9 in C2C12 cells and primary mouse myoblasts accelerates the transition from proliferation to committed progenitor transcriptional programs. Furthermore, we unveil significant reorganization and downregulation of Septin9 during myogenic differentiation. Collectively, we propose that filmamentous septin structures and their orchestrated reorganization in myoblasts are part of a temporal regulatory mechanism governing the differentiation of myogenic progenitors. This study sheds light on the dynamic interplay between cytoskeletal components underlying controlled myogenic differentiation. Overall design: Bulk RNA-seq of C2C12 cells and primary myoblasts was performed in duplicates for a total of 2 conditions (4 C2C12 samples and 4 primary myoblast samples). C2C12 and primary myoblasts were subjected to Septin9 siRNA treatment and non-targeting siRNA was used as a control. C2C12 cells were myogenically differentiatied for 12 hours thorugh serum deprivation (sample collection 60 hours after Septin9 depletion) and primary myoblasts were cultured under proliferatve conditions (sample collection 48 hours after Septin9 depletion).