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Ryan Christopher Riddle, Ph.D.

Photo of Dr. Ryan Christopher Riddle, Ph.D.

Director, Bone Biology subcore of Diabetes Research Center

Assistant Professor of Orthopaedic Surgery

Research Interests: Musculoskeletal development, Skeletal metabolism, Wnt signaling

Contact for Research Inquiries

Orthopaedic Research Labs
720 Rutland Avenue
Ross Research Building
Baltimore, MD 21205 map


Dr. Ryan Riddle is an assistant professor of orthopaedic surgery at the Johns Hopkins University School of Medicine.  He earned his Ph.D. from Pennsylvania State University College of Medicine and completed postdoctoral fellowships at the University of Alabama at Birmingham and Johns Hopkins University School of Medicine.

Dr. Riddle’s research focuses on Wnt/b-catenin signaling in musculoskeletal development and in response to mechanical, hormonal, and other anabolic signals. His prior work examined skeletal mechanotransduction—the process in which mechanical signals are translated to biochemical signals.

He is a member of the American Society for Bone & Mineral Research and the Endocrine Society. His work has been recognized with a 2011-2012 Musculoskeletal Pilot and Feasibility Grant from the JHU Center for Musculoskeletal Research and is supported by grants from the Veterans Administration and the National Institutes of Health. more


  • Director, Bone Biology subcore of Diabetes Research Center
  • Assistant Professor of Orthopaedic Surgery

Departments / Divisions



  • B.S., Loyola University (Maryland) (2002)
  • Ph.D., Pennsylvania State University (Pennsylvania) (2007)

Additional Training

University of Alabama, Birmingham, AL, 2007

Research & Publications

Research Summary

Research in Dr. Riddle’s laboratory is focused on Wnt/b-catenin signaling in musculoskeletal development.  He utilizes mouse genetics to examine receptor and intracellular signaling mechanisms.  In one project, he is interested in the unique and overlapping functions of Wnt signaling components in the accrual of bone and muscle mass.  The Wnt pathway consists of 10 highly related Frizzled receptors, two co-receptors, and several ligands that activate signaling, and human mutations that modify signaling efficacy are associated with both high and low bone mass phenotypes.  Using transgenic mice lacking Wnt signaling components in bone or muscle cells, his research seeks to determine the requirement for this signaling pathway during bone and muscle development and in the response to mechanical, hormonal, and other anabolic signals.  In a second, but related project, his laboratory has found that mice lacking the Wnt co-receptor, low density lipoprotein-related receptor-5, in osteoblasts accumulate body fat and develop dyslipidemia.  These findings have led to new studies designed to examine the energetic requirements of bone cells and to determine how the skeleton communicates its metabolic needs to other tissues.

Selected Publications

View all on Pubmed

Frey JL, Li Z, Ellis JM, Zhang Q, Farber CR, Aja S, Wolfgang MJ, Clemens TL, Riddle RC. 2015. Wnt-Lrp5 signaling regulates fatty acid metabolism in the osteoblast. Mol Cell Biol. 35:1979-1991.

Riddle RC, Frey JL, Ferron M, Li Y, DiGirolamo DJ, Faugere MC, Hussain MA, Karsenty G, Clemens TL. 2014. Tsc2 is a molecular checkpoint controlling osteoblast development and glucose homeostasis. Mol Cell Biol. 34:1850-1862.

Riddle RC, Diegel CR, Leslie JM, Van Koevering KK, Faugere MC, Clemens TL,Williams BO. 2013 Lrp5 and Lrp6 Exert Overlapping Functions in Osteoblasts During Postnatal Bone Acquisition. PLoS ONE 8(5): e63323. doi:10.1371/journal.pone.0063323.

Riddle RC, Leslie JM, Gross TS, Clemens TL. 2011. Hypoxia-inducible factor-1a protein negatively regulates load-induced bone formation. J Biol Chem. 286:44449-44456.

Mavalli MD, DiGirolamo DJ, Fan Y, Riddle RC, Campbell K, Sperling MA, van Groen T, Frank SJ, Bamman MM, Clemens TL. 2010. Differential Growth Hormone Receptor Signaling Modes Regulate Skeletal Muscle Development and Insulin Sensitivity. J Clin Invest. 120:4007-4020.

Fulzele K, Riddle RC, DiGirolamo DJ, Cao X, Wan C, Chen D, Faugere MC, Hussain MA, Brüning JC, Clemens TL. 2010. Insulin receptor signaling in osteoblasts regulates postnatal bone acquisition and body composition. Cell. 142:309-319.

Academic Affiliations & Courses

Graduate Program Affiliation

Cellular and Molecular Medicine

Activities & Honors


  • Musculoskeletal Pilot and Feasibility Grant, JHU Center for Musculoskeletal Research, 2011 - 2012
  • Career Development Award, Veterans Administration, 2011
  • Young Investigator Award, American Society for Bone and Mineral Research


  • American Society for Bone & Mineral Research
  • International Bone & Mineral Society
  • Endocrine Society
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