Short-chain fatty acids and FFAR2 as suppressors of bone resorption

C C Montalvany-Antonucci; L F Duffles; J A A de Arruda; M C Zicker; S de Oliveira; S Macari; G P Garlet; M F M Madeira; S Y Fukada; I Andrade Jr; M M Teixeira; C Mackay; A T Vieira; M A Vinolo; T A Silva

doi:10.1016/j.bone.2019.05.016

Short-chain fatty acids and FFAR2 as suppressors of bone resorption

Bone. 2019 Aug:125:112-121. doi: 10.1016/j.bone.2019.05.016. Epub 2019 May 14.

Authors

C C Montalvany-Antonucci¹, L F Duffles², J A A de Arruda², M C Zicker³, S de Oliveira⁴, S Macari⁵, G P Garlet⁶, M F M Madeira⁷, S Y Fukada⁸, I Andrade Jr⁹, M M Teixeira¹⁰, C Mackay¹¹, A T Vieira¹⁰, M A Vinolo⁴, T A Silva¹²

Affiliations

¹ Department of Oral Surgery and Pathology, Faculty of Dentistry, Federal University of Minas Gerais, MG, Brazil; Department of Orthodontics, Faculty of Dentistry, Pontifical Catholic University, Belo Horizonte, MG, Brazil.
² Department of Oral Surgery and Pathology, Faculty of Dentistry, Federal University of Minas Gerais, MG, Brazil.
³ Department of Food Science, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
⁴ Laboratory of Immunoinflammation, Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas, Campinas, SP, Brazil.
⁵ Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
⁶ Department of Biological Sciences, School of Dentistry of Bauru, University of São Paulo, Bauru, SP, Brazil.
⁷ Department of Microbiology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
⁸ Department of Pharmacological Science, Faculty of Pharmacy, University of São Paulo, Ribeirão Preto, SP, Brazil.
⁹ Department of Orthodontics, Faculty of Dentistry, Pontifical Catholic University, Belo Horizonte, MG, Brazil.
¹⁰ Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
¹¹ Department of Immunology, Monash University, Melbourne, Australia.
¹² Department of Oral Surgery and Pathology, Faculty of Dentistry, Federal University of Minas Gerais, MG, Brazil. Electronic address: tarcilia@ufmg.br.

PMID: 31100533
DOI: 10.1016/j.bone.2019.05.016

Abstract

Short-chain fatty acids (SCFAs) exert a variety of immune and metabolic functions by binding to G-protein-coupled receptors, mainly free fatty acid receptor 2 (FFAR2). However, the effects of SCFAs and FFARs on bone remodeling, especially in alveolar bone, have been less explored. In this study, we investigated the influence of the SCFA/FFAR2 axis on alveolar bone. Bone samples from wild-type (WT) and FFAR2-deficient mice (FFAR2-/-) were analyzed using micro-CT, histology and qPCR. WT and FFAR2-/- animals received a high-fiber diet (HFD) reported to increase circulating levels of SCFAs. Additionally, we analyzed the effects of SCFAs and a synthetic FFAR2 agonist, phenylacetamide-1 (CTMB), on bone cell differentiation. The participation of histone deacetylase inhibitors (iHDACs) in the effects of SCFAs was further assessed in vitro. CTMB treatment was also evaluated in vivo during orthodontic tooth movement (OTM). FFAR2-/- mice exhibited deterioration of maxillary bone parameters. Consistent with this, FFAR2-/- mice exhibited a significant increase of OTM and changes in bone cell numbers and in the expression of remodeling markers. The HFD partially reversed bone loss in the maxillae of FFAR2-/- mice. In WT mice, the HFD induced changes in the bone markers apparently favoring a bone formation scenario. In vitro, bone marrow cells from FFAR2-/- mice exhibited increased differentiation into osteoclasts, while no changes in osteoblasts were observed. In line with this, differentiation of osteoclasts was diminished by SCFAs and CTMB. Moreover, CTMB treatment significantly reduced OTM. Pretreatment of osteoclasts with iHDACs did not modify the effects of SCFAs on these cells. In conclusion, SCFAs function as regulators of bone resorption. The effects of SCFAs on osteoclasts are dependent on FFAR2 activation and are independent of the inhibition of HDACs. FFAR2 agonists may be useful to control bone osteolysis.

Keywords: Bone remodeling; FFAR2 protein; Short-chain fatty acids.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Bone Marrow Cells / cytology
Bone Marrow Cells / drug effects
Bone Marrow Cells / metabolism
Bone Resorption / drug therapy
Cell Differentiation / drug effects
Cells, Cultured
Fatty Acids, Volatile / pharmacology*
Male
Mice
Mice, Inbred C57BL
Osteoblasts / drug effects
Osteoblasts / metabolism
Osteoclasts / drug effects*
Osteoclasts / metabolism*
Receptors, G-Protein-Coupled / genetics
Receptors, G-Protein-Coupled / metabolism*
X-Ray Microtomography

Substances

Fatty Acids, Volatile
Ffar2 protein, mouse
Receptors, G-Protein-Coupled