Cystathionine γ-Lyase-Hydrogen Sulfide Induces Runt-Related Transcription Factor 2 Sulfhydration, Thereby Increasing Osteoblast Activity to Promote Bone Fracture Healing.
OBJECTIVE
Hydrogen sulfide (H2S) plays an essential role in bone formation, in part, by inhibiting osteoclast differentiation, maintaining mesenchymal stem cell osteogenesis ability, or reducing osteoblast injury. We aimed to investigate the role of H2S in osteoblast function and its possible molecular target.


RESULTS
In this study, we found that cystathionine γ-lyase (CSE) majorly contributed to endogenous H2S production in the primary osteoblast. Overexpressed CSE increased osteoblast differentiation and maturation with higher bone morphogenetic protein 2 and osteopontin expression, alkaline phosphatase activity, and calcium nodule formation; in contrast, knockdown of CSE had opposite effects. Runt-related transcript factor 2 (RUNX2) is required for osteoblast biologic function. CSE-H2S increased nuclear RUNX2 accumulation, DNA binding activity, and target gene transcription. Protein sulfhydration is a common signal by H2S. We confirmed that RUNX2 was also sulfhydrated by H2S. This chemical modification enhanced RUNX2 transactivation, which was blocked by dithiothreitol (DTT, sulfhydration remover). Mutation of two cysteine sites in the runt domain of RUNX2 abolished H2S-induced RUNX2 sulfhydration and transactivation. In a bone -fracture rat model, overexpressed CSE promoted bone healing, which confirmed the effect of CSE-H2S on osteoblasts.


METHODS
CSE-H2S is a dominant H2S generation system in osteoblasts and promotes osteoblast activity by the RUNX2 pathway, with RUNX2 sulfhydration as a novel transactivation regulation.


CONCLUSIONS
CSE-H2S sulfhydrated RUNX2 enhanced its transactivation and increased osteoblast differentiation and maturation, thereby promoting bone healing. Antioxid. Redox Signal. 27, 742-753.
1 Hypertension Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases , Beijing, China .|2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Yang
Y
Zheng
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .|3 Department of Orthopedics, Sichuan Provincial People's Hospital, Chengdu , China .
Feng
F
Liao
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Xianjuan
X
Lin
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Fengjiao
F
Zheng
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Jinghui
J
Fan
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Qinghua
Q
Cui
2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Jichun
J
Yang
1 Hypertension Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases , Beijing, China .|2 Department of Physiology and Pathophysiology, Department of Osteology-Peking University Third Hospital, Center for Noncoding RNA Medicine, Peking University Health Science Center , Beijing, China .
Bin
B
Geng
1 Hypertension Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases , Beijing, China .
Jun
J
Cai
D000818:Animals; D002454:Cell Differentiation; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism*; D003542:Cystathionine gamma-Lyase / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005269:Femur / Q000293:injuries; D017102:Fracture Healing; D050723:Fractures, Bone / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism*; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D050659:Core Binding Factor Alpha 1 Subunit; C493709:RUNX2 protein, human; D003542:Cystathionine gamma-Lyase; D006862:Hydrogen Sulfide
cystathionine γ-lyase; differentiation; hydrogen sulfide; osteoblast; runt-related transcript factor 2; sulfhydration