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.