Toll-like receptor ligand-dependent inflammatory responses in chick skeletal muscle myoblasts

Toll-like receptor ligand-dependent inflammatory responses in chick skeletal muscle myoblasts

Yuma Nihashi, Tamao Ono, Hiroshi Kagami, Tomohide Takaya.

Graduate School of Science and Technology, Shinshu University, Nagano, Japan.

2018 International Symposium on Animal Science and Technology (Ina, Japan), 2018/08/10 (Poster).

Abstract

Summary: Toll-like receptors (TLRs) are essential for innate immune system. However, it has not been reported whether TLRs initiate inflammatory responses in chick skeletal muscle myoblasts which are myogenic precursor cells. Here, we confirmed the distinct expression patterns of TLR genes between broiler and layer myoblasts. We also found that TLR ligands can induce inflammatory cytokines in chick myoblasts. These results demonstrate that TLR-dependent pathways in myoblasts might be involved in muscle development or growth of chickens.

Materials & Methods Primary-cultured myoblasts were prepared from E10 embryos of broiler (UK Chunky) and layer (White Leghorn) chickens. Myoblasts were maintained in growth medium and stimulated with TLR ligands; triacylated lipopeptide (Pam3CSK4), diacylated lipopeptide (FSL-1), or lipopolysaccharide (LPS). Gene expression levels were quantified by qRT-PCR.

Results & Discussion RT-PCR revealed that layer myoblasts express all TLR homologs but broiler myoblasts lack TLR1A expression. Both of broiler and layer spleens express all TLRs, which indicates that broiler myoblasts have a unique expression pattern of TLRs. Broiler myoblasts were stimulated with TLR ligands then subjected to qPCR. Pam3CSK4 as well as FSL-1 intensely led interleukin 1β expression. Pam3CSK4 highly and FSL-1 moderately induced interleukin 6 and 8. However, LPS did not induce any interleukins. These data indicate that chick myoblasts can produce inflammatory cytokines through TLR-dependent pathways. It might be related to the skeletal muscle inflammation observed in broiler chickens.