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In Vitro Cell Dev Biol Anim. 2019 Jan;55(1):45-51. doi: 10.1007/s11626-018-0304-0. Epub 2018 Nov 5.

Production of 8-nitro-cGMP in osteocytic cells and its upregulation by parathyroid hormone and prostaglandin E2.

Author information

1
Department of Biochemistry, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan.
2
Department of Orthodontics, Showa University School of Dentistry, Shinagawa, Japan.
3
Department of Biochemistry, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan. yoichim@dent.showa-u.ac.jp.
4
Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Shinjuku, Japan.
5
Department of Environmental Health Sciences and Molecular Toxicology, Tohoku University Graduate School of Medicine, Sendai, Japan.

Abstract

Osteocytes regulate bone remodeling, especially in response to mechanical loading and unloading of bone, with nitric oxide reported to play an important role in that process. In the present study, we found that 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP), a second messenger of nitric oxide in various types of cells, was produced by osteocytes in bone tissue as well as cultured osteocytic Ocy454 cells. The amount of 8-nitro-cGMP in Ocy454 cells increased during incubation with parathyroid hormone or prostaglandin E2, both of which are known to upregulate receptor activator of nuclear factor-κB ligand (RANKL) mRNA expression in osteocytes. On the other hand, exogenous 8-nitro-cGMP did not have effects on either the presence or absence of these bioactive substances. Furthermore, neither an inhibitor of nitric oxide synthase nor 8-bromo-cGMP, a cell-permeable analog of cGMP, showed remarkable effects on mRNA expression of sclerostin or RANKL. These results indicate that neither nitric oxide nor its downstream compounds, including 8-nitro-cGMP, alone are sufficient for induction of functional changes in osteocytes.

KEYWORDS:

8-Nitro-cGMP; Nitric oxide; Osteocytes; Parathyroid hormone

PMID:
30397855
DOI:
10.1007/s11626-018-0304-0
[Indexed for MEDLINE]

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