TY - JOUR
T1 - Protease-activated receptor 1 deletion causes enhanced osteoclastogenesis in response to inflammatory signals through a Notch2-dependent mechanism
AU - Jastrzebski, Sandra
AU - Kalinowski, Judith
AU - Mun, Sehwan
AU - Shin, Bongjin
AU - Adapala, Naga Suresh
AU - Jacome-Galarza, Christian E.
AU - Mirza, Faryal
AU - Leonardo Aguila, H.
AU - Drissi, Hicham
AU - Sanjay, Archana
AU - Canalis, Ernesto
AU - Lee, Sun Kyeong
AU - Lorenzo, Joseph A.
N1 - Funding Information:
This work was supported by grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01 AR048714 and R01 AR068160) and the National Institute of Diabetes, Digestive and Kidney Diseases (R01 DK045227) of the National Institutes of Health.
Publisher Copyright:
© 2019 by The American Association of Immunologists, Inc.
PY - 2019
Y1 - 2019
N2 - We found that protease-activated receptor 1 (PAR1) was transiently induced in cultured osteoclast precursor cells. Therefore, we examined the bone phenotype and response to resorptive stimuli of PAR1-deficient (knockout [KO]) mice. Bones and bone marrow-derived cells from PAR1 KO and wild-type (WT) mice were assessed using microcomputed tomography, histomorphometry, in vitro cultures, and RT-PCR. Osteoclastic responses to TNF-a (TNF) challenge in calvaria were analyzed with and without a specific neutralizing Ab to the Notch2-negative regulatory region (N2-NRR Ab). In vivo under homeostatic conditions, there were minimal differences in bone mass or bone cells between PAR1 KO and WT mice. However, PAR1 KO myeloid cells demonstrated enhanced osteoclastogenesis in response to receptor activator of NF-kB ligand (RANKL) or the combination of RANKL and TNF. Strikingly, in vivo osteoclastogenic responses of PAR1 KO mice to TNF were markedly enhanced. We found that N2-NRR Ab reduced TNF-induced osteoclastogenesis in PAR1 KO mice to WT levels without affecting WT responses. Similarly, in vitro N2-NRR Ab reduced RANKL-induced osteoclastogenesis in PAR1 KO cells to WT levels without altering WT responses. We conclude that PAR1 functions to limit Notch2 signaling in responses to RANKL and TNF and moderates osteoclastogenic response to these cytokines. This effect appears, at least in part, to be cell autonomous because enhanced osteoclastogenesis was seen in highly purified PAR1 KO osteoclast precursor cells. It is likely that this pathway is involved in regulating the response of bone to diseases associated with inflammatory signals.
AB - We found that protease-activated receptor 1 (PAR1) was transiently induced in cultured osteoclast precursor cells. Therefore, we examined the bone phenotype and response to resorptive stimuli of PAR1-deficient (knockout [KO]) mice. Bones and bone marrow-derived cells from PAR1 KO and wild-type (WT) mice were assessed using microcomputed tomography, histomorphometry, in vitro cultures, and RT-PCR. Osteoclastic responses to TNF-a (TNF) challenge in calvaria were analyzed with and without a specific neutralizing Ab to the Notch2-negative regulatory region (N2-NRR Ab). In vivo under homeostatic conditions, there were minimal differences in bone mass or bone cells between PAR1 KO and WT mice. However, PAR1 KO myeloid cells demonstrated enhanced osteoclastogenesis in response to receptor activator of NF-kB ligand (RANKL) or the combination of RANKL and TNF. Strikingly, in vivo osteoclastogenic responses of PAR1 KO mice to TNF were markedly enhanced. We found that N2-NRR Ab reduced TNF-induced osteoclastogenesis in PAR1 KO mice to WT levels without affecting WT responses. Similarly, in vitro N2-NRR Ab reduced RANKL-induced osteoclastogenesis in PAR1 KO cells to WT levels without altering WT responses. We conclude that PAR1 functions to limit Notch2 signaling in responses to RANKL and TNF and moderates osteoclastogenic response to these cytokines. This effect appears, at least in part, to be cell autonomous because enhanced osteoclastogenesis was seen in highly purified PAR1 KO osteoclast precursor cells. It is likely that this pathway is involved in regulating the response of bone to diseases associated with inflammatory signals.
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U2 - 10.4049/jimmunol.1801032
DO - 10.4049/jimmunol.1801032
M3 - Article
C2 - 31109956
AN - SCOPUS:85068429337
SN - 0022-1767
VL - 203
SP - 105
EP - 116
JO - Journal of Immunology
JF - Journal of Immunology
IS - 1
ER -