title: TRIM33 is essential for osteoblast proliferation and differentiation via BMP pathway.
abstract: Tripartite motif containing 33 (TRIM33) functions both as a positive and negative regulator of the TGF-β/BMP pathway in tumors; however, its effect and mechanism during osteoblast proliferation and differentiation, which involves the TGF-β/BMP pathway is not defined. In this study, we used mouse C3H10T1/2 mesenchymal stem cell line and MC3T3-E1 preosteoblasts to investigate the role of TRIM33 during this process. The results demonstrated that the expression of TRIM33 increased during the differentiation. Moreover, the overexpression or knockdown of TRIM33 resulted in both an augmentation or decrease in osteoblast differentiation, which were measured by the expression of alkaline phosphatase (ALP) at the mRNA level, both Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) at the protein level, and the formation of mineral modules. To further demonstrate the mechanism of TRIM33 in this process, we found that TRIM33 could positively mediate the BMP pathway by forming TRIM33-Smad1/5 complex. This interaction between TRIM33 and Smad1/5 triggered the phosphorylation of Smad1/5. In addition, the essential role of TRIM33 in osteoblast proliferation was determined in this study by CellCounting Kit (CCK) -8 and cell cycle assays. In summary, we establish the function of TRIM33 as a positive regulator of osteoblast differentiation in BMP pathway, which mediates its effect through its interaction with and activation of Smad1/5. In addition, the results clearly demonstrate that TRIM33 is necessary for osteoblast proliferation by regulating cell cycle. These results suggest that TRIM33 can be a positive target of osteoblast proliferation and differentiation through BMP pathway.
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Xing
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Manman
authors.initials: M
authors.lastname: Gao
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Fuxin
authors.initials: F
authors.lastname: Wei
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Song
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Xianling
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangdong, China.
authors.forename: Zhengmei
authors.identifier: http://orcid.org/0000-0003-1586-3741
authors.initials: Z
authors.lastname: Lin
mesh_terms: D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation; D049109:Cell Proliferation; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D010006:Osteoblasts / Q000378:metabolism*; D015675:Osteocalcin / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D034622:RNA Interference; D015398:Signal Transduction; D051898:Smad1 Protein / Q000378:metabolism; D051902:Smad5 Protein / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D019485:Bone Morphogenetic Proteins; D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; D051902:Smad5 Protein; C497798:Smad5 protein, mouse; D014157:Transcription Factors; C491420:Trim33 protein, mouse; D015675:Osteocalcin; D000469:Alkaline Phosphatase
keywords: TGF-β/BMP pathway; TRIM33; differentiation; osteoblast; proliferation