Download characterization of myogenic factors derived from a

CHARACTERIZATION OF MYOGENIC FACTORS DERIVED FROM A STABLE
MACROPHAGE CELL LINES
A. Malerba1, I. Scambi1, D. Segat1, M. Frigo1, P. De Coppi2, P. Gamba2, L. Boldrin2, L.
Cavallini4, R. Bellomo3, G. Fanò3, L. Vecchiett3, L. Vitiello1,3 and D. Baroni1,3
1Department of Biology, 2Pediatric Surgery & 4Biochemistry, University of Padova,
Italy
3InterUniversity Myology Istitute, Chieti, Italy
The interplay between macrophages and muscle precursors, critical for myogenesis, is
still poorly known. We have already reported that the murine macrophage cell line J774
can produce, in the absence of serum, a Macrophage-Conditioned Medium (MCM) that
contains muscle specific growth factors.
Here we show that MCM can strongly stimulate (up to 2 fold) the proliferation rate of
primary rat myoblasts and pure rat satellite cells. Interestingly, in both cases cell division
and cytoplasmic growth were partially uncoupled by MCM, with a loss of 30-35% of the
mean cell mass respect to control. Primary rat myoblasts, fully inhibited to form
myotubes when co-cultured with other cell types, could instead produce a very extensive
network of contractile myotubes if exposed to MCM.
Some of the in vitro properties of MCM were also compared to those of purified
myogenic factors. The presence of known myogenic factors in active MCM preparations
is also under investigation. The potential usefulness of MCM for expanding myoblast
populations will be discussed.