MIR208B: MIR208B is a microRNA that is encoded within the intron of the MYH7 gene, which codes for the slow isoform of Myosin Heavy Chain (MyHC). It has been shown to play a role in regulating mitochondrial function and metabolism in cooperation with KLF4, ESRR, and PGC-1 [PMC5586433]. MIR208B is differentially expressed in a sex- and hypertrophy-dependent manner, with an increase reported in hypertrophy [PMC5586433]. It is generated from an intron of Myh7, which is the cardiac fetal isoform that switches to Myh6 after birth [PMC5586433]. MIR208B has been implicated in the regulation of skeletal muscle fiber type switch to Myh7 through its interaction with PPARα and ESRRG [PMC7123062]. It has also been associated with cardiac hypertrophy and its downregulation has been observed in patients with amyotrophic lateral sclerosis (ALS) [PMC5573384] [PMC8424364]. MIR208B has been shown to target genes such as Sox6, Sp3, Thrap1, EZH2, EED, and SUZ12 [PMC4488424] [PMC4754821]. Additionally, changes in MIR208B expression have been observed during muscle atrophy and cancer cachexia [PMC8260947] [PMC8396502]. The role of MIR208B in regulating muscle regeneration and differentiation can be influenced by essential amino acid intake [PMC8466275]. Plasma levels of MIR208B have also been found to be elevated by cardiovascular damage [PMC3157373]