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HACD1, a regulator of membrane composition and fluidity, promotes myoblast fusion and skeletal muscle growth.

Blondelle J, Ohno Y, Gache V, Guyot S, Storck S, Blanchard-Gutton N, Barthélémy I, Walmsley G, Rahier A, Gadin S, Maurer M, Guillaud L, Prola A, Ferry A, Aubin-Houzelstein G, Demarquoy J, Relaix F, Piercy RJ, Blot S, Kihara A, Tiret L, Pilot-Storck F - J Mol Cell Biol (2015)

Bottom Line: In this study, we investigate the role of HACD1/PTPLA, which is involved in the elongation of the very long chain fatty acids, in muscle fibre formation.In humans and dogs, HACD1 deficiency leads to a congenital myopathy with fibre size disproportion associated with a generalized muscle weakness.These lipid modifications correlate with a reduction in plasma membrane rigidity.

View Article: PubMed Central - PubMed

Affiliation: Inserm, IMRB U955-E10, 94000 Créteil, France Université Paris-Est, Ecole nationale vétérinaire d'Alfort (EnvA), 94700 Maisons-Alfort, France Université Paris-Est Créteil, Faculté de médecine, 94000 Créteil, France.

No MeSH data available.


Related in: MedlinePlus

Defective myoblast fusion in normally differentiating HACD1-deficient myoblasts. (A and B) Immunodetection on muscle primary cell cultures from control or Hacd1−/− newborns on Day 2 of differentiation of the myosin heavy chains (MHC, green). Nuclei are in blue. Scale bar, 100 μm. (C) Unchanged differentiation index in HACD1-deficient myoblasts, i.e. percentage of nuclei contained in MHC-positive cells (n = 5 for each newborn group; ≥1000 nuclei per sample). (D) Decreased fusion index in HACD1-deficient myoblasts, i.e. average number of nuclei per myotube (n = 5 for each newborn group; ≥100 myotubes per sample). (E) Percent distribution of myotubes analysed in D by their number of nuclei. Error bars correspond to standard error of the mean. *P < 0.05, **P < 0.01, ***P < 0.001.
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MJV049F4: Defective myoblast fusion in normally differentiating HACD1-deficient myoblasts. (A and B) Immunodetection on muscle primary cell cultures from control or Hacd1−/− newborns on Day 2 of differentiation of the myosin heavy chains (MHC, green). Nuclei are in blue. Scale bar, 100 μm. (C) Unchanged differentiation index in HACD1-deficient myoblasts, i.e. percentage of nuclei contained in MHC-positive cells (n = 5 for each newborn group; ≥1000 nuclei per sample). (D) Decreased fusion index in HACD1-deficient myoblasts, i.e. average number of nuclei per myotube (n = 5 for each newborn group; ≥100 myotubes per sample). (E) Percent distribution of myotubes analysed in D by their number of nuclei. Error bars correspond to standard error of the mean. *P < 0.05, **P < 0.01, ***P < 0.001.

Mentions: To further confirm the impairment of myoblast fusion and determine if this defect was combined with a depletion in satellite cells, we first assessed in mice muscles the number of Pax7-positive satellite cells from which myoblasts differentiate to form new myofibres. Both immunofluorescence and RT-qPCR experiments indicated a similar expression of Pax7 in Hacd1−/− mice compared with controls (Supplementary Figure S3A–D), excluding reduced numbers of satellite cells as causative of hypotrophy. We then used the capacity of primary myoblasts isolated from young pups to differentiate in vitro to characterize the contribution of Hacd1 in fusion. After 2 days of differentiation, cells isolated from control and Hacd1−/− pups similarly formed myotubes and the number of nuclei within myosin heavy chain-positive cells was similar, indicating normal myoblast commitment into the differentiation process (Figure 4A–C). In contrast, myotubes were globally smaller in cultures from Hacd1−/− pups and presented a reduced fusion index assessed by the average number of nuclei per myotube (Figure 4A, B, and D). Accordingly, distribution of myotubes with respect to their number of nuclei revealed fewer myotubes with ≥6 nuclei, and greater numbers of small myotubes with only 2 nuclei compared with controls (Figure 4E).Figure 4


HACD1, a regulator of membrane composition and fluidity, promotes myoblast fusion and skeletal muscle growth.

Blondelle J, Ohno Y, Gache V, Guyot S, Storck S, Blanchard-Gutton N, Barthélémy I, Walmsley G, Rahier A, Gadin S, Maurer M, Guillaud L, Prola A, Ferry A, Aubin-Houzelstein G, Demarquoy J, Relaix F, Piercy RJ, Blot S, Kihara A, Tiret L, Pilot-Storck F - J Mol Cell Biol (2015)

Defective myoblast fusion in normally differentiating HACD1-deficient myoblasts. (A and B) Immunodetection on muscle primary cell cultures from control or Hacd1−/− newborns on Day 2 of differentiation of the myosin heavy chains (MHC, green). Nuclei are in blue. Scale bar, 100 μm. (C) Unchanged differentiation index in HACD1-deficient myoblasts, i.e. percentage of nuclei contained in MHC-positive cells (n = 5 for each newborn group; ≥1000 nuclei per sample). (D) Decreased fusion index in HACD1-deficient myoblasts, i.e. average number of nuclei per myotube (n = 5 for each newborn group; ≥100 myotubes per sample). (E) Percent distribution of myotubes analysed in D by their number of nuclei. Error bars correspond to standard error of the mean. *P < 0.05, **P < 0.01, ***P < 0.001.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589950&req=5

MJV049F4: Defective myoblast fusion in normally differentiating HACD1-deficient myoblasts. (A and B) Immunodetection on muscle primary cell cultures from control or Hacd1−/− newborns on Day 2 of differentiation of the myosin heavy chains (MHC, green). Nuclei are in blue. Scale bar, 100 μm. (C) Unchanged differentiation index in HACD1-deficient myoblasts, i.e. percentage of nuclei contained in MHC-positive cells (n = 5 for each newborn group; ≥1000 nuclei per sample). (D) Decreased fusion index in HACD1-deficient myoblasts, i.e. average number of nuclei per myotube (n = 5 for each newborn group; ≥100 myotubes per sample). (E) Percent distribution of myotubes analysed in D by their number of nuclei. Error bars correspond to standard error of the mean. *P < 0.05, **P < 0.01, ***P < 0.001.
Mentions: To further confirm the impairment of myoblast fusion and determine if this defect was combined with a depletion in satellite cells, we first assessed in mice muscles the number of Pax7-positive satellite cells from which myoblasts differentiate to form new myofibres. Both immunofluorescence and RT-qPCR experiments indicated a similar expression of Pax7 in Hacd1−/− mice compared with controls (Supplementary Figure S3A–D), excluding reduced numbers of satellite cells as causative of hypotrophy. We then used the capacity of primary myoblasts isolated from young pups to differentiate in vitro to characterize the contribution of Hacd1 in fusion. After 2 days of differentiation, cells isolated from control and Hacd1−/− pups similarly formed myotubes and the number of nuclei within myosin heavy chain-positive cells was similar, indicating normal myoblast commitment into the differentiation process (Figure 4A–C). In contrast, myotubes were globally smaller in cultures from Hacd1−/− pups and presented a reduced fusion index assessed by the average number of nuclei per myotube (Figure 4A, B, and D). Accordingly, distribution of myotubes with respect to their number of nuclei revealed fewer myotubes with ≥6 nuclei, and greater numbers of small myotubes with only 2 nuclei compared with controls (Figure 4E).Figure 4

Bottom Line: In this study, we investigate the role of HACD1/PTPLA, which is involved in the elongation of the very long chain fatty acids, in muscle fibre formation.In humans and dogs, HACD1 deficiency leads to a congenital myopathy with fibre size disproportion associated with a generalized muscle weakness.These lipid modifications correlate with a reduction in plasma membrane rigidity.

View Article: PubMed Central - PubMed

Affiliation: Inserm, IMRB U955-E10, 94000 Créteil, France Université Paris-Est, Ecole nationale vétérinaire d'Alfort (EnvA), 94700 Maisons-Alfort, France Université Paris-Est Créteil, Faculté de médecine, 94000 Créteil, France.

No MeSH data available.


Related in: MedlinePlus