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Prostaglandin F2(alpha) stimulates growth of skeletal muscle cells via an NFATC2-dependent pathway.

Horsley V, Pavlath GK - J. Cell Biol. (2003)

Bottom Line: We demonstrate that prostaglandin F2alpha (PGF2alpha) as well as two analogues augment muscle cell size in vitro.We show that NFAT is activated by PGF2alpha, and the isoform NFATC2 is required for PGF2alpha-induced muscle cell growth and nuclear accretion, demonstrating the first intersection between prostaglandin receptor activation and NFAT signaling.Given this novel role for PGF2alpha in skeletal muscle cell growth, these studies raise caution that extended use of drugs that inhibit PG production, such as nonsteroidal antiinflammatory drugs, may be deleterious for muscle growth.

View Article: PubMed Central - PubMed

Affiliation: Cell and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.

ABSTRACT
Skeletal muscle growth requires multiple steps to form large multinucleated muscle cells. Molecules that stimulate muscle growth may be therapeutic for muscle loss associated with aging, injury, or disease. However, few factors are known to increase muscle cell size. We demonstrate that prostaglandin F2alpha (PGF2alpha) as well as two analogues augment muscle cell size in vitro. This increased myotube size is not due to PGF2alpha-enhancing cell fusion that initially forms myotubes, but rather to PGF2alpha recruiting the fusion of cells with preexisting multinucleated cells. This growth is mediated through the PGF2alpha receptor (FP receptor). As the FP receptor can increase levels of intracellular calcium, the involvement of the calcium-regulated transcription factor nuclear factor of activated T cells (NFAT) in mediating PGF2alpha-enhanced cell growth was examined. We show that NFAT is activated by PGF2alpha, and the isoform NFATC2 is required for PGF2alpha-induced muscle cell growth and nuclear accretion, demonstrating the first intersection between prostaglandin receptor activation and NFAT signaling. Given this novel role for PGF2alpha in skeletal muscle cell growth, these studies raise caution that extended use of drugs that inhibit PG production, such as nonsteroidal antiinflammatory drugs, may be deleterious for muscle growth.

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PGF2α increases myotube size by facilitating muscle cell fusion. (A) Primary myoblasts were induced to differentiate in the presence of vehicle (10−6 M PGF2α or 10−7 M 17-phPGF2α) and immunostained for EMyHC at the indicated times. Bar, 60 μm. (B) The DNA content of myotube cultures treated with vehicle or 10−6 M PGF2α was quantified after 48 h in DM. (C) The percentage of nuclei within EMyHC-positive cells was analyzed after treatment with vehicle or 10−6 M PGF2α at the indicated times. (D) The percentage of nuclei within myotubes was calculated after treatment with vehicle or 10−6 M PGF2α at the indicated times. (E) Cells were treated with the indicated doses of PGF2α for 48 h, and the number of nuclei within individual myotubes was counted. Myotubes were grouped into two categories, and the percentage of myotubes in each category was determined. Data are mean ± SEM of three independent cell isolates. *Significantly different from vehicle, P < 0.05. (F) Cells were treated with the indicated doses of 17-phPGF2α for 48 h, and the number of nuclei within individual myotubes was counted as in E. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05. (G) Cells were treated with vehicle or 10−6 M PGF2α at 0, 24, or both 0 and 24 h. Nuclear number assays were performed as in E, and the percentage of myotubes with five or more nuclei is shown. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05.
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fig1: PGF2α increases myotube size by facilitating muscle cell fusion. (A) Primary myoblasts were induced to differentiate in the presence of vehicle (10−6 M PGF2α or 10−7 M 17-phPGF2α) and immunostained for EMyHC at the indicated times. Bar, 60 μm. (B) The DNA content of myotube cultures treated with vehicle or 10−6 M PGF2α was quantified after 48 h in DM. (C) The percentage of nuclei within EMyHC-positive cells was analyzed after treatment with vehicle or 10−6 M PGF2α at the indicated times. (D) The percentage of nuclei within myotubes was calculated after treatment with vehicle or 10−6 M PGF2α at the indicated times. (E) Cells were treated with the indicated doses of PGF2α for 48 h, and the number of nuclei within individual myotubes was counted. Myotubes were grouped into two categories, and the percentage of myotubes in each category was determined. Data are mean ± SEM of three independent cell isolates. *Significantly different from vehicle, P < 0.05. (F) Cells were treated with the indicated doses of 17-phPGF2α for 48 h, and the number of nuclei within individual myotubes was counted as in E. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05. (G) Cells were treated with vehicle or 10−6 M PGF2α at 0, 24, or both 0 and 24 h. Nuclear number assays were performed as in E, and the percentage of myotubes with five or more nuclei is shown. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05.

Mentions: To test the hypothesis that PGF2α has a role in the growth of skeletal muscle cells, differentiating primary muscle cultures were treated with different doses of PGF2α or with a stable synthetic analogue of PGF2α, 17-phenyl trinor PGF2α (17-phPGF2α). After 24 h, the majority of cells are differentiated and have formed a few multinucleated cells. Although no difference is apparent between the vehicle- and drug-treated groups at 24 h, after 48 h, drug-treated myotubes are larger in size as compared with vehicle (Fig. 1 A), suggesting that PGF2α can regulate muscle growth.


Prostaglandin F2(alpha) stimulates growth of skeletal muscle cells via an NFATC2-dependent pathway.

Horsley V, Pavlath GK - J. Cell Biol. (2003)

PGF2α increases myotube size by facilitating muscle cell fusion. (A) Primary myoblasts were induced to differentiate in the presence of vehicle (10−6 M PGF2α or 10−7 M 17-phPGF2α) and immunostained for EMyHC at the indicated times. Bar, 60 μm. (B) The DNA content of myotube cultures treated with vehicle or 10−6 M PGF2α was quantified after 48 h in DM. (C) The percentage of nuclei within EMyHC-positive cells was analyzed after treatment with vehicle or 10−6 M PGF2α at the indicated times. (D) The percentage of nuclei within myotubes was calculated after treatment with vehicle or 10−6 M PGF2α at the indicated times. (E) Cells were treated with the indicated doses of PGF2α for 48 h, and the number of nuclei within individual myotubes was counted. Myotubes were grouped into two categories, and the percentage of myotubes in each category was determined. Data are mean ± SEM of three independent cell isolates. *Significantly different from vehicle, P < 0.05. (F) Cells were treated with the indicated doses of 17-phPGF2α for 48 h, and the number of nuclei within individual myotubes was counted as in E. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05. (G) Cells were treated with vehicle or 10−6 M PGF2α at 0, 24, or both 0 and 24 h. Nuclear number assays were performed as in E, and the percentage of myotubes with five or more nuclei is shown. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05.
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fig1: PGF2α increases myotube size by facilitating muscle cell fusion. (A) Primary myoblasts were induced to differentiate in the presence of vehicle (10−6 M PGF2α or 10−7 M 17-phPGF2α) and immunostained for EMyHC at the indicated times. Bar, 60 μm. (B) The DNA content of myotube cultures treated with vehicle or 10−6 M PGF2α was quantified after 48 h in DM. (C) The percentage of nuclei within EMyHC-positive cells was analyzed after treatment with vehicle or 10−6 M PGF2α at the indicated times. (D) The percentage of nuclei within myotubes was calculated after treatment with vehicle or 10−6 M PGF2α at the indicated times. (E) Cells were treated with the indicated doses of PGF2α for 48 h, and the number of nuclei within individual myotubes was counted. Myotubes were grouped into two categories, and the percentage of myotubes in each category was determined. Data are mean ± SEM of three independent cell isolates. *Significantly different from vehicle, P < 0.05. (F) Cells were treated with the indicated doses of 17-phPGF2α for 48 h, and the number of nuclei within individual myotubes was counted as in E. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05. (G) Cells were treated with vehicle or 10−6 M PGF2α at 0, 24, or both 0 and 24 h. Nuclear number assays were performed as in E, and the percentage of myotubes with five or more nuclei is shown. Data are mean ± SEM of three independent experiments. *Significantly different from vehicle, P < 0.05.
Mentions: To test the hypothesis that PGF2α has a role in the growth of skeletal muscle cells, differentiating primary muscle cultures were treated with different doses of PGF2α or with a stable synthetic analogue of PGF2α, 17-phenyl trinor PGF2α (17-phPGF2α). After 24 h, the majority of cells are differentiated and have formed a few multinucleated cells. Although no difference is apparent between the vehicle- and drug-treated groups at 24 h, after 48 h, drug-treated myotubes are larger in size as compared with vehicle (Fig. 1 A), suggesting that PGF2α can regulate muscle growth.

Bottom Line: We demonstrate that prostaglandin F2alpha (PGF2alpha) as well as two analogues augment muscle cell size in vitro.We show that NFAT is activated by PGF2alpha, and the isoform NFATC2 is required for PGF2alpha-induced muscle cell growth and nuclear accretion, demonstrating the first intersection between prostaglandin receptor activation and NFAT signaling.Given this novel role for PGF2alpha in skeletal muscle cell growth, these studies raise caution that extended use of drugs that inhibit PG production, such as nonsteroidal antiinflammatory drugs, may be deleterious for muscle growth.

View Article: PubMed Central - PubMed

Affiliation: Cell and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.

ABSTRACT
Skeletal muscle growth requires multiple steps to form large multinucleated muscle cells. Molecules that stimulate muscle growth may be therapeutic for muscle loss associated with aging, injury, or disease. However, few factors are known to increase muscle cell size. We demonstrate that prostaglandin F2alpha (PGF2alpha) as well as two analogues augment muscle cell size in vitro. This increased myotube size is not due to PGF2alpha-enhancing cell fusion that initially forms myotubes, but rather to PGF2alpha recruiting the fusion of cells with preexisting multinucleated cells. This growth is mediated through the PGF2alpha receptor (FP receptor). As the FP receptor can increase levels of intracellular calcium, the involvement of the calcium-regulated transcription factor nuclear factor of activated T cells (NFAT) in mediating PGF2alpha-enhanced cell growth was examined. We show that NFAT is activated by PGF2alpha, and the isoform NFATC2 is required for PGF2alpha-induced muscle cell growth and nuclear accretion, demonstrating the first intersection between prostaglandin receptor activation and NFAT signaling. Given this novel role for PGF2alpha in skeletal muscle cell growth, these studies raise caution that extended use of drugs that inhibit PG production, such as nonsteroidal antiinflammatory drugs, may be deleterious for muscle growth.

Show MeSH
Related in: MedlinePlus