AUTHOR=Rementer Cameron , Yavirach Apichai , Buranaphatthana Worakanya , Walczak Philip A. , Speer Mei , Pierce Kat , Dharmarajan Subramanian , Leber Elizabeth , Sangiorzan Bruce , Bain Steven , Scatena Marta , Blümke Alexander , Giachelli Cecilia M. TITLE=Engineered myeloid precursors differentiate into osteoclasts and resorb heterotopic ossification in mice JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=12 YEAR=2024 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2024.1491962 DOI=10.3389/fbioe.2024.1491962 ISSN=2296-4185 ABSTRACT=Introduction

Heterotopic ossification (HO) occurs following orthopedic trauma, spinal cord injuries, brain trauma and limb amputations. Once symptomatic, HO causes pain, limited mobility and decreased quality of life. Current treatments are limited and have significant complications with high recurrence rates, underscoring the need for improved therapeutic interventions. Osteoclasts (OCs) are physiological bone resorptive cells that secrete enzymes and protons to degrade bone.

Methods

In this study, we describe the use of genetically engineered OCs as a novel cell therapy approach to treat HO. Inducible, engineered myeloid precursors (iRANK cells) treated with a chemical inducer of dimerization (CID) differentiated into TRAP+ multinucleated OCs and resorbed mineralized tissues in vitro.

Results

In vivo, BMP-2-induced murine HO lesions were significantly regressed following treatment using iRANK cells with concomitant systemic administration of CID. Moreover, many OCs were TRAP+, MMP9+, and GFP+, indicating that they differentiated from delivered iRANK cells.

Discussion

In summary, these data con rm the ability of engineered myeloid precursors to differentiate into OCs and resorb HO in vivo paving the way for OC delivery as a promising approach for HO treatment.