Transcriptional and Histochemical Signatures of Bone Marrow Mononuclear Cell-Mediated Resolution of Synovitis.

Autor:	Menarim BC; Department of Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States., El-Sheikh Ali H; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States.; Theriogenology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt., Loux SC; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States., Scoggin KE; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States., Kalbfleisch TS; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States., MacLeod JN; Gluck Equine Research Center, Department of Veterinary Sciences, College of Agricultural, Food and Environment, University of Kentucky, Lexington, KY, United States., Dahlgren LA; Department of Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in immunology [Front Immunol] 2021 Dec 08; Vol. 12, pp. 734322. Date of Electronic Publication: 2021 Dec 08 (Print Publication: 2021).
DOI:	10.3389/fimmu.2021.734322
Abstrakt:	Osteoarthritis (OA) may result from impaired ability of synovial macrophages to resolve joint inflammation. Increasing macrophage counts in inflamed joints through injection with bone marrow mononuclear cells (BMNC) induces lasting resolution of synovial inflammation. To uncover mechanisms by which BMNC may affect resolution, in this study, differential transcriptional signatures of BMNC in response to normal (SF) and inflamed synovial fluid (ISF) were analyzed. We demonstrate the temporal behavior of co-expressed gene networks associated with traits from related in vivo and in vitro studies. We also identified activated and inhibited signaling pathways and upstream regulators, further determining their protein expression in the synovium of inflamed joints treated with BMNC or DPBS controls. BMNC responded to ISF with an early pro-inflammatory response characterized by a short spike in the expression of a NF-ƙB- and mitogen-related gene network. This response was associated with sustained increased expression of two gene networks comprising known drivers of resolution ( IL-10, IGF-1, PPARG , isoprenoid biosynthesis). These networks were common to SF and ISF, but more highly expressed in ISF. Most highly activated pathways in ISF included the mevalonate pathway and PPAR-γ signaling, with pro-resolving functional annotations that improve mitochondrial metabolism and deactivate NF-ƙB signaling. Lower expression of mevalonate kinase and phospho-PPARγ in synovium from inflamed joints treated with BMNC, and equivalent IL-1β staining between BMNC- and DPBS-treated joints, associates with accomplished resolution in BMNC-treated joints and emphasize the intricate balance of pro- and anti-inflammatory mechanisms required for resolution. Combined, our data suggest that BMNC-mediated resolution is characterized by constitutively expressed homeostatic mechanisms, whose expression are enhanced following inflammatory stimulus. These mechanisms translate into macrophage proliferation optimizing their capacity to counteract inflammatory damage and improving their general and mitochondrial metabolism to endure oxidative stress while driving tissue repair. Such effect is largely achieved through the synthesis of several lipids that mediate recovery of homeostasis. Our study reveals candidate mechanisms by which BMNC provide lasting improvement in patients with OA and suggests further investigation on the effects of PPAR-γ signaling enhancement for the treatment of arthritic conditions. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2021 Menarim, El-Sheikh Ali, Loux, Scoggin, Kalbfleisch, MacLeod and Dahlgren.)
Databáze:	MEDLINE
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