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Ryan C. Riddle, PhD

Academic Title:

Faculty Member

Primary Appointment:

Orthopaedics

Additional Title:

Health Sciences Specialist, Research Service and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD

Phone (Primary):

(410) 706-0422

Education and Training

Education

1998-2002: B.S., Biology, Loyola College in Maryland

2002-2007: Ph.D. Cellular and Molecular Biology, The Pennsylvania University State University College of Medicine

 

Post-Doctoral Training

2007-2009: Department of Pathology and Center for Metabolic Bone Disease, The University of Alabama at Birmingham

2009-2010: Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine

Biosketch

Ryan C. Riddle, PhD is a faculty member in the Department of Orthopaedics at the University of Maryland School of Medicine and holds a co-appointment in the Research and Development Service of the Baltimore Veterans Administration Medical Center.  

Dr. Riddle graduate from Loyola College in Maryland with a Bachelor of Science in Biology before pursuing a Ph.D. in Cell and Molecular Biology at The Pennsylvania State University College of Medicine.  He completed his dissertation on the effects of mechanical signals in bone marrow mesenchymal stem proliferation and differentiation in the laboratory of Dr. Henry Donahue.  In 2007, he joined the laboratory of Dr. Thomas Clemens at the University of Alabama at Birmingham for postdoctoral training focused on hormone signaling in osteoblasts. The laboratory moved in 2010 to Department of Orthopaedic Surgery at The Johns Hopkins University School of Medicine.  Dr. Riddle was appointed as an Assistant Professor at Johns Hopkins in 2010 and was promoted to the rank of Associate Professor in 2017.  In 2022, Dr. Riddle was recruited to the Department of Orthopaedics at the University of Maryland School of Medicine.

Dr. Riddle's work is supported by grants from the U.S. Department of Veterans Affairs and the National Institutes of Health.  In addition to serving on study sections for the NIH and international funding agencies he is an Editorial Board member for Journal of Bone and Mineral Research, Bone Research, and Frontiers in Endocrinology, Bone Research as well as a member of the Board of Consulting Editors for Journal of Clinical Investigation.

Research/Clinical Keywords

Osteoblast, Adipocyte, Wnt Signaling, Sclerostin, Fatty Acid Metabolism, musculoskeletal biology, integrative physiology.

Highlighted Publications

Kim SP, Da H, Wang L, Taketo MM, Wan M, Riddle RC. Bone-derived sclerostin and Wnt/β-catenin signaling regulate PDGFRa+ adipoprogenitor cell differentiation. FASEB J, 35:e21957.

Kushwaha P, Kim S, Foxa GE, Michalski MN, Williams BO, Tomlinson RE, Riddle RC. Frizzled-4 is required for normal bone acquisition despite compensation by Frizzled-8. J Cell Physiol, 235:6673-6683.

Kim SP, Da H, Li Z, Kushwaha P, Beil C, Mei L, Xiong XC, Wolfgang MJ, Clemens TL, Riddle RC. Lrp4 expression by adipocytes and osteoblasts differentially impacts sclerostin’s endocrine effects on body composition and glucose metabolism.  J Biol Chem, 294:6899-6911.

Frey JL, Kim SP, Li Z, Wolfgang MJ, Riddle RC. β-catenin directs long-chain fatty acid catabolism in the osteoblasts of male mice. Endocrinology, 159:272-284.

Kim SP, Frey JL, Li Z, Kushwaha P, Zoch ML, Tomlinson RE, Da H, Aja S, Noh HL, Kim JK, Hussain MA, Thorek DLJ, Wolfgang MJ, Riddle RC. Sclerostin influences body composition by regulating catabolic acid and anabolic metabolism in adipocytes. Proc Natl Acad Sci USA, 114(52): E11238-11247, 2017.

Kim SP, Frey JL, Li Z, Goh BC, Riddle RC. Lack of Lrp5 signaling in osteoblasts sensitizes male mice to diet-induced disturbances in glucose metabolism. Endocrinology, 58(11):3805-3816.

Kim SP, Li Z, Zoch ML, Frey JL, Bowman CE, Kushwaha P, Ryan KA, Goh BC, Scafidi S, Pickett JE, Faugere MC, Kershaw EE, Thorek DLJ, Clemens TL, Wolfgang MJ, Riddle RC. Fatty acid oxidation by the osteoblast is required for normal bone acquisition in a sex and diet-dependent manner. JCI Insight, 2(16):e92704.

Zoch ML, Abou DS, Clemens TL, Thorek DLJ, Riddle RC. In vivo radiometric analysis of glucose uptake and distribution in mouse bone. Bone Res, 4:16004. dx.doi.org/10.1038/boneres. 2016.4

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 

 

Additional Publication Citations

Alekos NS, Moorer MC, Riddle RC. Dual effects of lipid metabolism on osteoblast function. Front Endocrinol,11:578194.

Dirckx N, Moorer MC, Clemens TL, Riddle RC. Role of the osteoblast in energy homeostasis. Nat Rev Endocrinol, 15:651-665.

Moorer MC, Riddle RC. 2018. Regulation of osteoblast metabolism by Wnt signaling. Endocrinol Metab (Seoul), 33:318-330.

Kushwaha P, Wolfgang MJ, Riddle RC. Fatty acid metabolism by the osteoblast. Bone, 115:8-14.

Riddle RC, Clemens TL. Bone Cell Bioenergetics and Skeletal Energy Homeostasis.  Physiol Rev, 97:667-698.

Zoch ML, Clemens TL, Riddle RC. New insights into the biology of osteocalcin. Bone, 82:42-49.

 

 

 

 

 

Research Interests

Research in the Riddle Laboratory is focused on 1) understanding the role of Wnt/b-catenin signaling in musculoskeletal development and the response to mechanical, hormonal, and other anabolic signals, and 2) determining the contributions of osteoblast intermediary metabolism and bone-derived endocrine factors to the coordination of whole-body metabolism.

Grants and Contracts

Current Research Support

07/24/2013-3/31/2023 "Regulation of Osteoblast Metabolism by Lrp5" NIH/NIDDK R01 DK099134. Role: PI

04/01/2021-3/30/2026 "Bone-Adipose Interactions During Skeletal Anabolism: NIH/NIAMS R01 AR077533. Role: PI

01/01/2022-12/31/2026 "Endocrine Actions of Sclerostin" VA Merit Review Award I01 BX003724. Role: PI