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

Abstract

Toll-like receptors (TLRs) are a group of sensory receptors which are capable of recognizing a microbial invasion and activating innate immune system responses, including inflammatory responses, in both immune and non-immune cells. However, TLR functions in chick myoblasts, which are myogenic precursor cells contributing to skeletal muscle development and growth, have not been studied. Here, we report the expression patterns of TLR genes as well as TLR ligand-dependent transcriptions of interleukin (IL) genes in primary-cultured chick myoblasts. Almost TLR genes were expressed both in layer and broiler myoblasts but TLR1A was detected only in embryonic layer chick myoblasts. Chick TLR1/2 ligands, Pam3CSK4 and FSL-1, induced inflammatory ILs in both broiler and layer myoblasts but a TLR4 ligand, lipopolysaccharide, scarcely promoted. This is the first report on TLR ligand-dependent inflammatory responses in chick myoblasts, which may provide useful information to chicken breeding and meat production industries.

Enhanced cytokine expression and upregulation of inflammatory signaling pathways in broiler chickens affected by wooden breast myopathy

“…However, the expression profile of TLRs and their functions in chicken skeletal muscle have been rarely investigated. In this study, we detected nine TLR genes expressed in muscle of broilers except TLR1A , which was in accordance with a recent study suggesting that TLR1A transcription might be silenced during embryonic myotube formation in chickens 37 . Remarkably, all of these detected TLR genes and their adaptor MyD88 were transcriptionally upregulated in WB compared to CON.…”

Identification of the myogenetic oligodeoxynucleotides (myoDNs) that promote differentiation of skeletal muscle myoblasts by targeting nucleolin

“…Immunocytochemistry of myoblasts was performed as previously described (Takaya et al, 2017; Nihashi et al, 2019a; Nihashi et al, 2019b). The myoblasts were fixed with 2% paraformaldehyde, permeabilized with 0.2% Triton X-100, and immunostained with 0.5 μg/ml mouse monoclonal anti-myosin heavy chain (MHC) antibody (MF20; R&D Systems, MN, USA) and 1.0 μg/ml rabbit polyclonal anti-nucleolin antibody (ab22758; Abcam, Cambridge, UK).…”

“…Immunocytochemistry of myoblasts was performed as previously described (Takaya et al, 2017;Nihashi et al, 2019a;Nihashi et al, 2019b).…”

Distinct cell proliferation, myogenic differentiation, and gene expression in skeletal muscle myoblasts of layer and broiler chickens

“…Myoblasts from hindlimb muscles of WL or UKC chicken embryos at HH36 (E10) were isolated, primary-cultured, and induced to differentiate as previously described 57,58 . Conventional WL and UKC chicken eggs were provided by National Federation of Agricultural Cooperative Associations (Tokyo, Japan) and were conventionally cultured at 38.5 °C and 60% humidity with 45° horizontal rotation every 3.75 min in an incubation chamber for 10 days.…”