Page 27 - G. Cell differentiation. division. and death

A branched-chain fatty acid ameliorates ovariectomy-induced osteoporosis
by inhibiting osteoclast differentiation
Kwang Min Cho, Ye Seon Kim, Mingyu Lee, Ha Young Lee, and Yoe-Sik Bae 1,2,*
1
1
2
1
1 Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
2 Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Republic of Korea
BACKGROUND AIM
Osteoclasts (OCs) are multinucleated cells derived from the monocyte/macrophage lineage In this study, we examined whether IVA affects the
which are known as the OC progenitors. In the bone, OC activity is importantly involved in the activity of macrophages and their differentiation
regulation of bone metabolism and homeostasis with OC specific enzymes such as cathepsin into OCs. Therefore, We also examined the in vivo
K (CTSK) and tartrate-resistant acid phosphatase (TRAP). Therefore, modulation of OC effects of IVA on the regulation of osteoporosis, an
differentiation and activity is crucial for the maintenance of bone homeostasis in the human
body. OC-associated disorder.
Branched chain fatty acids (BCFAs) are made from essential amino acids including valine,
isoleucine, and leucine by microbial fermentation, to form isobutyric acid with 4 carbons, or 2-
methylbutyric acid and isovaleric acid (IVA) with 5 carbons.
METHODS

1. Generation of mouse bone marrow-derived macrophages (BMDMs)
The non-adherent cells of bone marrow cells were cultured for three days with α-MEM containing 10% FBS and M-CSF (30 ng/ml).
2. OC differentiation and TRAP staining
Mouse BMDMs (1×10 cells/well) were differentiated into immature OCs using M-CSF (30 ng/ml) and RANKL (100 ng/ml) in 96-well plate.
4
3. OVX mouse model
Mice were anesthetized by inhalation anesthesia and ovaries were bilaterally removed. To examine the effects of IVA on OVX mice, IVA was added
to the drinking water (at a final concentration of 75 mM or 150 mM) from the day after surgery.
RESULTS

Figure 1. IVA stimulates BMDMs Figure 2. IVA blocks RANKL-induced Figure 3. IVA regulates the expression of
leading to chemotactic migration. osteoclastogenesis. RANKL-induced OC-related genes.

The BCFA inhibited the expression of
OC-related genes. The BCFA-induced
inhibitory effects on OC generation
was blocked by pertussis toxin (PTX)
but not by protein kinase A (PKA)
inhibitor H89, suggesting that G i -
coupled receptor-dependent but PKA-
independent response. Furthermore,
the BCFA stimulates AMPK
phosphorylation, besides the BCFA-
induced inhibition of OC generation
was blocked by AMPK inhibitor. In an
ovariectomized mouse model, the
group that drank water containing the
BCFA significantly recovered body
Figure 4. IVA-induced inhibitory effects on Figure 5. IVA shows therapeutic effects weight loss and decreased the
osteoclastogenesis is mediated by G i - against OVX-induced osteoporosis. expression of OC-related genes and
coupled GPCR and AMPK. fusogenic genes in total bone tissue.
CONCLUSION REFERENCES Contact information

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