Interleukin-1β stimulates early myogenesis of mouse C2C12 myoblasts: the impact on myogenic regulatory factors, extracellular matrix components, IGF binding proteins and protein kinases

Abstract

The purpose of the study was to examine the mechanisms important for early myogenesis in mouse C2C12 myogenic cells exposed to interleukin-1β. Cyclin A and cyclin B1 were increased by interleukin-1β (1 ng/ml), but the level of cyclin D1 and total DNA content was unaffected. Fusion index and the rate of protein synthesis was increased in the presence of IL-1β, but these effects were limited to 3-day-treatment. IL-1β increased the level of MyoD, myogenin and MHC on the 3 rd day of differentiation, without altering the content of the active form of myostatin, as well as it augmented the level of fibronectin, integrin β1 and full length 100 kDa form of ADAM12. IL-1β caused a decrease in IGFBP-4 and IGFBP-6 levels and a marked increase in IGFBP-5. The phosphorylation of PKB and ERK1/2 and the cellular content of p38 were elevated by IL-1β. We conclude that the myogenic effect of IL-1β was limited to the onset of myoblast fusion and was associated with: i) increase in the level of myogenic transcription factors i.e. MyoD and myogenin expression, ii) modification of extracellular matrix assembly and signaling, manifested by an increase in fibronectin, integrin-β1 and ADAM12 content, iii) drop in IGFBP-4 and IGFBP-6, and an increase in IGFBP-5, that could alter the local IGF-1 bioavailability, and iv) increase in phosphorylation of PKB and ERK1/2, and the expression of p38 kinase, leading to activation of intracellular pathways essential for myogenic differentiation.

Tumor necrosis factor-α alters integrins and metalloprotease ADAM12 levels and signaling in differentiating myoblasts

“…In this regard, our present data demonstrating an increase in FAK and ILK expression under TNF-α treatment have some discrepancy with cytokine-induced insulin resistance described in fully differentiated myotubes and mature muscle fibers (summarized in O'Connor et al 2008). Our results are, however, compatible with previous studies describing the positive effects of factors released after muscle injury on satellite cells (Goetsch et al 2003) and the transient stimulatory effects of proinflammatory cytokines on myoblasts in culture (Grabiec et al 2013), and support the diversity of proinflammatory cytokine effects in proliferating and fully differentiated cells.…”

“…Apparently, ADAM12-cytoskeleton interactions, and, in turn, ADAM12 breakdown are diminished in the presence of TNF-α, that is in line with increased cellular level of the metalloprotease under cytokine treatment. In our previous study a long 100 kDa isoform of ADAM12 was increased in myoblasts differentiating for 3 days in the presence of IL-1β (Grabiec et al 2013) and IGF-I (Grzelkowska- Kowalczyk et al 2015), suggesting similar effects of proinflammatory cytokines and anabolic growth factors on early stages of myogenesis.…”

“…Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as described previously (Grabiec et al 2013). In both assays the absorbance was measured on a multidetection microplate reader Infinite 200 PRO Tecan TM (TECAN, Mannedorf, Switzerland) at a wavelength of 570 nm.…”

“…It has been shown to promote muscle wasting in several pathological conditions (Yeh et al 2008) and to impair anabolic hormone/factor signaling in mature myotubes in vitro (Grzelkowska-Kowalczyk and et al 2013), and is required for skeletal muscle cells to respond to growth factors (Li and Velleman 2009, Miura et al 2010, Yasaka et al 2013. It has been shown that neither the expression of myogenin, one of muscle regulatory transcription factors (Zammit et al 2006), nor its localization to myoblast nuclei were sufficient to drive skeletal muscle differentiation, if interactions cell-ECM were inhibited (Osses et al 2009).…”

Role of proinflammatory cytokines and growth factors in skeletal muscle regeneration

“…Co ciekawe, IL-6, która bierze udział w degradacji białek i degeneracji mięśni (61), może wywoły-wać proliferację komórek satelitowych i regenerację tkanki mięśniowej (5), co potwierdza przypuszczenia, że cytokina ta jest zaangażowana w etap przejściowy od ostrego zapalenia do naprawy (31). Inne cytokiny prozapalne, TNF-α i IL-1β, stymulują wczesne etapy miogenezy, takie jak: fuzja mioblastów, tworzenie aktywnych kompleksów receptorów integrynowych i synteza metaloproteinaz macierzy zewnątrzkomór-kowej (21,66), co może sprzyjać oddziaływaniom komórka-macierz, adhezji komórkowej i naprawie uszkodzonych włókien mięśniowych poprzez włącza-nie jąder komórek satelitowych. Wymienione efekty wywołuje w mioblastach również IGF-I (24), co sugeruje, że cytokiny prozapalne i anaboliczne czynniki wzrostu dla mięśni wykazują podobne działanie na wczesnych etapach miogenezy.…”