AUTHOR=Momenzadeh Kaveh , Yeritsyan Diana , Abbasian Mohammadreza , Kheir Nadim , Hanna Philip , Wang Jialiang , Dosta Pere , Papaioannou Garyfallia , Goldfarb Sarah , Tang Cheng-Chia , Amar-Lewis Eliz , Nicole Prado Larrea Michaela , Martinez Lozano Edith , Yousef Mohamed , Wixted John , Wein Marc , Artzi Natalie , Nazarian Ara TITLE=Stimulation of fracture mineralization by salt-inducible kinase inhibitors JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=12 YEAR=2024 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2024.1450611 DOI=10.3389/fbioe.2024.1450611 ISSN=2296-4185 ABSTRACT=Introduction

Over 6.8 million fractures occur annually in the US, with 10% experiencing delayed- or non-union. Anabolic therapeutics like PTH analogs stimulate fracture repair, and small molecule salt inducible kinase (SIK) inhibitors mimic PTH action. This study tests whether the SIK inhibitor YKL-05-099 accelerates fracture callus osteogenesis.

Methods

126 female mice underwent femoral shaft pinning and midshaft fracture, receiving daily injections of PBS, YKL-05-099, or PTH. Callus tissues were analyzed via RT-qPCR, histology, single-cell RNA-seq, and μCT imaging. Biomechanical testing evaluated tissue rigidity. A hydrogel-based delivery system for PTH and siRNAs targeting SIK2/SIK3 was developed and tested.

Results

YKL-05-099 and PTH-treated mice showed higher mineralized callus volume fraction and improved structural rigidity. RNA-seq indicated YKL-05-099 increased osteoblast subsets and reduced chondrocyte precursors. Hydrogel-released siRNAs maintained target knockdown, accelerating callus mineralization.

Discussion

YKL-05-099 enhances fracture repair, supporting selective SIK inhibitors’ development for clinical use. Hydrogel-based siRNA delivery offers targeted localized treatment at fracture sites.