Disruption of the aldehyde dehydrogenase 2 gene increases the bone anabolic response to intermittent PTH treatment in an ovariectomized mouse model

• Published in: Bone (New York, N.Y.) Vol. 136; p. 115370
• Main Authors: Kosugi, Kenji, Tajima, Takafumi, Menuki, Kunitaka, Okuma, Kayoko Furukawa, Tokuda, Kotaro, Fukuda, Hokuto, Okada, Yasuaki, Tsukamoto, Manabu, Yamanaka, Yoshiaki, Zenke, Yukichi, Sakai, Akinori
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2020
• Subjects: Aldehyde Dehydrogenase; Aldehyde dehydrogenase 2; Aldehyde Dehydrogenase, Mitochondrial; Animals; Bone anabolic effect; Bone Density; Female; Mice; Mice, Knockout; Osteocyte; Ovariectomized mouse; p21; Parathyroid hormone; Parathyroid Hormone - pharmacology; PTH receptor; Receptor, Parathyroid Hormone, Type 1; ALDH2/Aldh2; PTH; ALP; Bone anabolic effect; TPTD; LRP; PTH receptor; BW; BMD; SOST; WT; Ovariectomized mouse; Runx2; PBS; Col1a1; KO; PTHR; micro-CT; p21; Parathyroid hormone; Veh; Aldehyde dehydrogenase 2; BTM; CFU-f; Osteocyte
• ISSN: 8756-3282; 1873-2763
• DOI: 10.1016/j.bone.2020.115370

Aldehyde dehydrogenase 2 (ALDH2) is the enzyme that oxidizes the acetaldehyde produced by alcohol metabolism. This variant not only affects the response to alcohol but is also associated with several diseases, such as esophageal cancer, myocardial infarction, and particularly osteoporosis. In our previous study, we reported that compared to wild-type (WT) mice, Aldh2 knockout (KO) mice naturally have a strong bone formation ability, and high expression of parathyroid hormone receptor (PTHR1) in osteocytes. The effect of the Aldh2 gene on bone metabolism in response to intermittent PTH treatment is unknown. The purpose of this study was to clarify the effect of the Aldh2 gene on the bone anabolic response to intermittent PTH treatment in ovariectomized mice. Female KO and WT mice were ovariectomized at 8 weeks of age. At 14 weeks of age, the KO and WT mice were divided into vehicle-treated (Veh) and PTH-treated (PTH) groups (i.e., the WT-Veh, WT-PTH, KO-Veh and KO-PTH groups). PTH (1–34) and vehicle were subcutaneously administered to each group at a dose of 40 μg/kg body weight (BW) five times per week for 4 weeks. Micro-CT showed that the bone volume (BV), trabecular number (Tb.N), connectivity density (Conn.D), and cortical thickness (Ct.Th) values in the KO-PTH mice were significantly higher than those in the KO-Veh mice. Histomorphometric analysis showed that the BV, Tb.N, and mineral apposition rate (MAR) values in the KO-PTH group were significantly higher than those in the KO-Veh group. The mRNA expression level of PTHR1 in the KO-PTH group was significantly increased and that of p21 in the KO-PTH group was significantly decreased compared with the levels in the KO-Veh group. The expression of PTHR in osteocytes from the KO-PTH group was also significantly increased compared with that in osteocytes from the KO-Veh group. Furthermore, cell cultures revealed that the ALP+CFU-f/total CFU-f percentage was significantly higher in the KO-PTH group than in the KO-Veh group. We concluded that in ovariectomized Aldh2 KO mice, the bone anabolic response to intermittent PTH treatment was significantly enhanced compared to that in WT mice, which may be mediated by the high expression level of PTHR1. •In an ovariectomized aldehyde dehydrogenase 2 (Aldh2) knockout (KO) mice, the bone anabolic response to intermittent PTH treatment was significantly enhanced compared to wild-type (WT) mice.•Aldh2 KO mice had high expression of PTHR1 in osteocytes. In an ovariectomized mouse model, the expression of PTHR in osteocytes was increased in only KO group by intermittent PTH treatment.•In an ovariectomized mouse model, aldh2 KO mice had high expression of p21 in osteocytes. The expression of p21 in osteocytes was decreased in only KO group by intermittent PTH treatment.