(A) Cyr61 expression increases in all modes of atrophy.
(B) By TMT-MS, Cyr61 protein was significantly upregulated with aging (but not detected with LLC and dexamethasone).
(C) Cyr61 mRNA and protein levels were significantly reduced in TA muscles of 30-month-old mice after electroporation of siRNAs targeting Cyr61 compared to control non-targeting (NT) siRNAs.
(D) Representative images of cross-sections from control (siNT) and Cyr61 siRNA (siCYR61)-treated TA muscles and immunostained for myosin heavy chain isotypes, as explained for Figure 1.
(E) There are no changes in the number of myofibers following Cyr61 knock down. However, the proportion of myofiber types shifts from 2X toward 2B, simultaneously causing a significant increase in the size of type 2X myofibers.
(F–H) Volcano plot of RNA-seq from TA muscles with Cyr61 knock down shows substantial transcriptional changes (F), including significant regulation of Wnt signaling signaling pathway components (G), which are shown in (H).