Targeted suppression of μ-calpain and caspase 9 expression and its effect on caspase 3 and caspase 7 in satellite cells of Korean Hanwoo cattle

The calpains play an important role in cell death and cell signalling. Caspases catalyse wholesale destruction of cellular proteins which is a major cause of cellular death. The current study looks at the function of μ‐calpain and caspase 9, using RNAi (RNA interference)‐mediated silencing, and to observe the mRNA expression level of caspase genes during satellite cell growth. The satellite cells were treated with siRNA (small interfering RNA) of μ‐calpain and caspase 9 separately. There was reduction of 16 and 24% in CAPN1 (calpain1)‐siRNA2 and CAPN1‐siRNA3 transfected cells respectively, whereas it was 60 and 56% in CAPN1‐siRNA1 and CAPN1‐siRNA4 transfected cells respectively. CAPN1‐siRNA4 and CAPN1‐siRNA1 treated cells showed more reduction in caspase 3 and 7 gene expression. CARD9 (caspase recruitment domain 9)‐siRNA1 and CARD9‐siRNA2‐treated cells showed reduction of 40 and 49% respectively. CARD9‐siRNA1 and CARD9‐siRNA2 showed an increase in caspase 3 gene expression, whereas CARD9‐siRNA2 showed reduction in caspase 7 gene expression. These results suggest a strong cross‐talk between μ‐calpain and the caspase enzyme systems. Suppression of target genes, such as μ‐calpain and caspase 9, might have genuine potential in the treatment of skeletal muscle atrophy.