Letter | Published:

Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis

Nature volume 540, pages 276279 (08 December 2016) | Download Citation


Platelet-derived growth factor receptor α (PDGFRα) exhibits divergent effects in skeletal muscle. At physiological levels, signalling through this receptor promotes muscle development in growing embryos and angiogenesis in regenerating adult muscle1,2. However, both increased PDGF ligand abundance and enhanced PDGFRα pathway activity cause pathological fibrosis3,4. This excessive collagen deposition, which is seen in aged and diseased muscle5,6,7, interferes with muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders8,9. Although compelling evidence exists for the role of PDGFRα in fibrosis, little is known about the cells through which this pathway acts. Here we show in mice that PDGFRα signalling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated10,11,12,13. We found that FAPs produce multiple transcriptional variants of Pdgfra with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signalling and to prevent FAP over-activation. Moreover, increasing the expression of this isoform limits fibrosis in vivo in mice, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem-cell populations.

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We would like to thank members of the Rando laboratory, especially A. de Morrée, M. Quarta, J. Shih, B. Yoo, V. Garcia and I. Akimenko for discussions and experimental assistance as well as L. Rott for guidance with FACS. This work was supported by the Glenn Foundation for Medical Research, by grants from the National Institutes of Health (F30 AG043235) and the California Institute for Regenerative Medicine (TG2-01159) to A.A.M., and by grants from the Department of Veterans Affairs and the NIH (P01 AG036695, R01 AG23806, R01 AR062185, and TR01 AG47820) to T.A.R.

Author information

Author notes

    • Alisa A. Mueller
    •  & Tom H. Cheung

    Present addresses: Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA (A.A.M); Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China (T.H.C.).


  1. Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, California, USA

    • Alisa A. Mueller
    • , Cindy T. van Velthoven
    • , Kathryn D. Fukumoto
    • , Tom H. Cheung
    •  & Thomas A. Rando
  2. Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA

    • Alisa A. Mueller
    • , Cindy T. van Velthoven
    • , Kathryn D. Fukumoto
    • , Tom H. Cheung
    •  & Thomas A. Rando
  3. Program in Cancer Biology, Stanford University School of Medicine, Stanford, California, USA

    • Alisa A. Mueller
  4. Neurology Service and Rehabilitation Research and Development REAP, Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA

    • Thomas A. Rando


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A.A.M. and T.A.R. conceived the study and were involved in the overall design of experiments. A.A.M. and T.H.C. designed, conducted and analysed the microarray and sequencing experiments as well as the FACS analyses. A.A.M. designed the morpholinos and siRNAs and also performed and analysed the associated experiments to test for their transcriptional effects. A.A.M. and C.T.V.V. designed the viral construct while C.T.V.V. created the construct and performed experiments to analyse expression. A.A.M. and C.T.V.V. designed and performed experiments and data analysis for PDGFRα protein expression and downstream signalling in response to morpholino treatment in vitro and in vivo as well as for muscle fibrosis responses. A.A.M. conducted and analysed the proliferation assays whereas C.T.V.V. performed and evaluated the scratch assays. K.D.F. carried out pilot experiments to assess for PDGFRα signalling in regenerating skeletal muscle and in initial FACS characterization of the FAP population. A.A.M. and T.A.R. wrote the manuscript with input from C.T.V.V. and T.H.C.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Thomas A. Rando.

Reviewer Information Nature thanks F. Rossi, Y. Shi and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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