Massachusetts General Hospital

Andrew Brack, Ph.D.
Assistant Professor of Medicine, Harvard Medical School
Brack.Andrew@mgh.harvard.edu

Faculty, Harvard University Program in Biological and Biomedical Sciences

In uninjured muscle, the rare satellite cells are in a functionally dormant, quiescent state. Upon an injury stimulus, these cells proliferate and their progeny will either differentiate to form new muscle fibers or undergo self renewal to replenish the stem cell pool.

We believe that the temporally coordinated cell fate decisions of the stem cell and its progeny are reliant on the communication between the local environment (the muscle stem cell niche) and the stem cell itself. We are using cre/lox gene recombination and genetic knock in technology to deconstruct the communication between the niche and the muscle stem cell to investigate the cell fate decision making process during regeneration. In the future we hope this will lead to strategies that improve stem cell based therapies targeting aging and muscle disease.

Research Fellows
Susan Eliazer, PhD
Swapna Kollu, PhD
Annarita Scaramozza, PhD
Lab Manager
Naveen Nunna, MSPhD Student
Josef ChristensenUndergraduate Student
Morgan Matthews

For research opportunities please contact Dr. Andrew Brack.

1. Charge, S., Brack, A.S., Hughes, S. M. (2002) Aging-related satellite cell differentiation defect occurs prematurely after Ski-induced muscle hypertrophy. Am.J.Cell.Physiol. 283:C1228-C1241. PMID: 12225986

2. Ferguson, R.E., Sun, Y.B., Mercier, P., Brack, A.S., Sykes, B.D., Corrie, J.E., Trentham, D.R., Irving, M. (2003) In situ orientations of protein domains: troponin C in skeletal muscle fibers. Mol.Cell. 11:865-74. PMID: 12718873

3. Brack, A.S., Brandmeier, B.D., Ferguson, R.E., Criddle, S., Dale, R.E., Irving, M. (2004) Bifunctional rhodamine probe of myosin regulatory light chain orientation in relaxed single muscle fibres. Biophys.J. 2004 86: 2329-2341.

4. Brack, A.S., Bildsoe, H., Hughes, S.M. (2005) A satellite cell defect leads to a loss of myonuclei in murine age-related atrophy and is exacerbated in large muscle fibres. J.Cell Sci. 118: 4813-21.

5. Bruusgaard, J.C., Brack, A.S., Hughes, S.M., Gundersen, K. (2005) Muscle hypertrophy induced by the Ski protein: Cyto-architecture and ultrastructure. Acta.Physiol.Scand. 185: 141-9. PMID: 16168008

6. Brack, A.S., Conboy, M.J., Roy, S., Lee, M., Kuo, C., Rando, T.A. (2007) Elevated Wnt signaling during aging alters the fate of myogenic stem cells leading to increased fibrosis and impaired regeneration. Science. 317: 807-810.

7. Brack, A.S. and Rando, T.A. (2007) Intrinsic changes and extrinsic influences of myogenic stem cell function during aging. Stem Cell Rev. 3: 226-237. PMID: 17917136

8. Brack, A.S., Conboy, I.M., Conboy, M.J., Shen, J, and Rando, T.A. (2008) A temporal switch from Notch to Wnt is necessary for normal adult myogenesis. Cell Stem Cell. 2, 50-59. PMID: 18371421

9. Brack, A.S., Charge, S., Bayol, S., Hughes, S. M. (2008) MyoD and nerve-dependent maintenance of myoD expression in mature muscle fibres acts through the DRR/PRR element. BMC: Dev. Biol. (1):5 PMCID: PMC2259323

10. Brack, A.S., Murphy-Seiler, F., Hanifi, J., Deka, J., Eyckerman, S., Keller, C., Aguet, M., and Rando, T.A. (2009). BCL9 is an essential component of canonical Wnt signaling that mediates the differentiation of myogenic progenitors during muscle regeneration. Developmental biology 335(1): 93-105. PMID: 19699733

11. Shea, K.L, Xiang, W., LaPorta, V.S., Licht, J.D., Keller, C., Basson, M.A., Brack, A.S. (2010) Sprouty1 Regulates Reversible Quiescence of a Self-Renewing Adult Muscle Stem Cell Pool during Regeneration. Cell Stem Cell  6: 117-129. PMID: 20144785

12. Warren L, Manos PD, Ahfeldt T, Loh YH, Li H, Lau F, Ebina W, Mandal PK, Smith ZD, Meissner A, Daley GQ, Brack, A.S., Collins JJ, Cowan C, Schlaeger TM, Rossi DJ. Highly efficient reprogramming to pluripotency and directed differentiation of human cells with synthetic modified mRNA.  Cell Stem Cell. 2010 Nov 5;7(5):618-30. Epub 2010 Sep 30.

Reviews, Chapters and Editorials.

1. Brack, A.S and Rando, T.A. (2007) Intrinsic changes and extrinsic influences of myogenic stem cell function during Aging. Stem Cell Rev. 3: 226-237.

2. Brack, A.S and Rando, T.A. (2008) Age-Dependent Changes in Skeletal Muscle Regeneration. Skeletal Muscle Repair and Regeneration. 359-374.

3. Brack, A.S. (2009) Adult muscle stem cells avoid death and Paxes. Cell Stem cell 5(2): 132-134.

4. Abou-Khalil, R and Brack, A.S. (2010) Muscle Stem Cells and Reversible Quiescence; The role of Sprouty. Cell Cycle. 9:13; 1-6.

5. Brack A.S., Rando TA. Tissue-specific stem cells: lessons from the skeletal muscle satellite cell.  Cell Stem Cell. 2012 May 4;10(5):504-14.