Letters to the Editor: Does Myostatin Induce Insulin Resistance? Buel D. Rodgers J. Biol. Chem. 2014, 289:21203. doi: 10.1074/jbc.L114.574707
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THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 289, NO. 30, p. 21203, July 25, 2014 Published in the U.S.A.
LETTER
Does Myostatin Induce Insulin Resistance?
JULY 25, 2014 • VOLUME 289 • NUMBER 30
Buel D. Rodgers1 Washington Center for Muscle Biology, Department of Animal Sciences, Washington State University, Pullman, Washington 99164-7620 1. Bonala, S., Lokireddy, S., McFarlane, C., Patnam, S., Sharma, M., and Kambadur, R. (2014) Myostatin induces insulin resistance via Casitas B-lineage lymphoma b (Cblb)-mediated degradation of insulin receptor substrate 1 (IRS1) protein in response to high calorie diet intake. J. Biol. Chem. 289, 7654 –7670 2. Lee, S. J., and McPherron, A. C. (2001) Regulation of myostatin activity and muscle growth. Proc. Natl. Acad. Sci. U.S.A. 98, 9306 –9311 3. Zimmers, T. A., Davies, M. V., Koniaris, L. G., Haynes, P., Esquela, A. F., Tomkinson, K. N., McPherron, A. C., Wolfman, N. M., and Lee, S. J. (2002) Induction of cachexia in mice by systemically administered myostatin. Science 296, 1486 –1488 4. McFarlane, C., Langley, B., Thomas, M., Hennebry, A., Plummer, E., Nicholas, G., McMahon, C., Sharma, M., and Kambadur, R. (2005) Proteolytic processing of myostatin is auto-regulated during myogenesis. Dev. Biol. 283, 58 – 69 5. Rodgers, B. D., Wiedeback, B. D., Hoversten, K. E., Jackson, M. F., Walker, R. G., and Thompson, T. B. (2014) Myostatin stimulates, not inhibits, C2C12 myoblast proliferation. Endocrinology 155, 670 – 675
DOI 10.1074/jbc.L114.574707 1
E-mail: [email protected]
JOURNAL OF BIOLOGICAL CHEMISTRY
21203
Downloaded from http://www.jbc.org/ at The University of Birmingham on August 20, 2014
Bonala et al. (1) report that high glucose or fat increases myostatin protein expression in muscle and surprisingly liver (cells and tissue) and that myostatin induces insulin resistance. Their myostatin antiserum used for Western blotting and possibly ELISAs (not discussed) recognizes a reported 26-kDa protein under reducing conditions despite a predicted and empirically determined 12.5-kDa mass (2, 3). This group previously reported that the antiserum recognizes the same 26-kDa protein in mstn⫺/⫺ muscle extracts (4). Zimmers et al. (3) also identified this protein in wild-type and mstn⫺/⫺ mice, although their antiserum detected only a 12.5-kDa band in wild-type mice. Moreover, several studies have demonstrated the lack of myostatin mRNA in liver. These findings together suggest that Bonala et al. (1) did not quantify myostatin as their antiserum appears to cross-react with an unknown protein. There is also concern with their use of recombinant myostatin made in bacteria, which cannot form the critical disulfide necessary for myostatin maturation. These recombinants may function as dominant negatives and were reported to inhibit C2C12 proliferation whereas different sources of recombinant myostatin generated in eukaryotes stimulate it (5). In fact, concentrations used by Bonala et al. (1) were supraphysiological, 100-fold
higher than the functional concentrations of recombinant myostatin made in eukaryotes, which greatly exceeds the nanomolar affinity range of ActRIIb. This use of highly questionable reagents in turn questions many of the authors’ conclusions. It also adds confusion to the field, and unless the reagents can be finally validated, their use should be discontinued.
Find articles, minireviews, Reflections and Classics on similar topics on the JBC Affinity Sites. Alerts: • When this article is cited • When a correction for this article is posted Click here to choose from all of JBC's e-mail alerts This article cites 5 references, 3 of which can be accessed free at http://www.jbc.org/content/289/30/21203.full.html#ref-list-1
Downloaded from http://www.jbc.org/ at The University of Birmingham on August 20, 2014
Access the most updated version of this article at http://www.jbc.org/content/289/30/21203
THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 289, NO. 30, p. 21203, July 25, 2014 Published in the U.S.A.
LETTER
Does Myostatin Induce Insulin Resistance?
JULY 25, 2014 • VOLUME 289 • NUMBER 30
Buel D. Rodgers1 Washington Center for Muscle Biology, Department of Animal Sciences, Washington State University, Pullman, Washington 99164-7620 1. Bonala, S., Lokireddy, S., McFarlane, C., Patnam, S., Sharma, M., and Kambadur, R. (2014) Myostatin induces insulin resistance via Casitas B-lineage lymphoma b (Cblb)-mediated degradation of insulin receptor substrate 1 (IRS1) protein in response to high calorie diet intake. J. Biol. Chem. 289, 7654 –7670 2. Lee, S. J., and McPherron, A. C. (2001) Regulation of myostatin activity and muscle growth. Proc. Natl. Acad. Sci. U.S.A. 98, 9306 –9311 3. Zimmers, T. A., Davies, M. V., Koniaris, L. G., Haynes, P., Esquela, A. F., Tomkinson, K. N., McPherron, A. C., Wolfman, N. M., and Lee, S. J. (2002) Induction of cachexia in mice by systemically administered myostatin. Science 296, 1486 –1488 4. McFarlane, C., Langley, B., Thomas, M., Hennebry, A., Plummer, E., Nicholas, G., McMahon, C., Sharma, M., and Kambadur, R. (2005) Proteolytic processing of myostatin is auto-regulated during myogenesis. Dev. Biol. 283, 58 – 69 5. Rodgers, B. D., Wiedeback, B. D., Hoversten, K. E., Jackson, M. F., Walker, R. G., and Thompson, T. B. (2014) Myostatin stimulates, not inhibits, C2C12 myoblast proliferation. Endocrinology 155, 670 – 675
DOI 10.1074/jbc.L114.574707 1
E-mail: [email protected]
JOURNAL OF BIOLOGICAL CHEMISTRY
21203
Downloaded from http://www.jbc.org/ at The University of Birmingham on August 20, 2014
Bonala et al. (1) report that high glucose or fat increases myostatin protein expression in muscle and surprisingly liver (cells and tissue) and that myostatin induces insulin resistance. Their myostatin antiserum used for Western blotting and possibly ELISAs (not discussed) recognizes a reported 26-kDa protein under reducing conditions despite a predicted and empirically determined 12.5-kDa mass (2, 3). This group previously reported that the antiserum recognizes the same 26-kDa protein in mstn⫺/⫺ muscle extracts (4). Zimmers et al. (3) also identified this protein in wild-type and mstn⫺/⫺ mice, although their antiserum detected only a 12.5-kDa band in wild-type mice. Moreover, several studies have demonstrated the lack of myostatin mRNA in liver. These findings together suggest that Bonala et al. (1) did not quantify myostatin as their antiserum appears to cross-react with an unknown protein. There is also concern with their use of recombinant myostatin made in bacteria, which cannot form the critical disulfide necessary for myostatin maturation. These recombinants may function as dominant negatives and were reported to inhibit C2C12 proliferation whereas different sources of recombinant myostatin generated in eukaryotes stimulate it (5). In fact, concentrations used by Bonala et al. (1) were supraphysiological, 100-fold
higher than the functional concentrations of recombinant myostatin made in eukaryotes, which greatly exceeds the nanomolar affinity range of ActRIIb. This use of highly questionable reagents in turn questions many of the authors’ conclusions. It also adds confusion to the field, and unless the reagents can be finally validated, their use should be discontinued.
