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Li S, Yan W, Sun K, Miao J, Liu Z, Xu J, Wang X, Li B, Zhang Q. Norisoboldine, a Natural Alkaloid from Lindera aggregata (Sims) Kosterm, Promotes Osteogenic Differentiation via S6K1 Signaling Pathway and Prevents Bone Loss in OVX Mice. Mol Nutr Food Res 2024; 68:e2400193. [PMID: 38813717 DOI: 10.1002/mnfr.202400193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/06/2024] [Indexed: 05/31/2024]
Abstract
SCOPE Norisoboldine (NOR) is a major isoquinoline alkaloid component in the traditional Chinese herbal plant Lindera aggregata (Sims) Kosterm, with previously reported anti-osteoclast differentiation and antiarthritis properties. However, the roles of NOR on osteoblasts, bone marrow mesenchymal stem cells (BMSCs), and osteoporosis in vivo have never been well established. METHODS AND RESULTS This study investigates the ability of NOR to improve bone formation in vitro and in vivo. Osteoblasts and BMSCs are used to study the effect of NOR on osteogenic and adipogenic differentiation. It finds that NOR promotes osteogenic differentiation of osteoblasts and BMSCs, while inhibiting adipogenic differentiation of BMSCs by reducing the relative expression of peroxisome proliferator-activated receptor γ (Ppar-γ) and adiponectin, C1Q and collagen domain containing (Adipoq). Mechanistic studies show that NOR increases osteoblast differentiation through the mechanistic target of rapamycin kinase (mTOR)/ribosomal protein S6 kinase; polypeptide 1 (S6K1) pathway, and treatment with an mTOR inhibitor rapamycin blocked the NOR-induced increase in mineral accumulation. Finally, the study evaluates the therapeutic potential of NOR in a mouse model of ovariectomy (OVX)-induced bone loss. NOR prevents bone loss in both trabecular and cortical bone by increasing osteoblast number and phospho-S6K1 (p-S6K1) expression in osteoblasts. CONCLUSION NOR effects in enhancing osteoblast-induced bone formation via S6K1 pathway, suggesting the potential of NOR in osteoporosis treatment by increasing bone formation.
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Affiliation(s)
- Shiming Li
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100193, China
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Wenliang Yan
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Kainong Sun
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100193, China
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Jingyuan Miao
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Zichao Liu
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Jiayang Xu
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Xiaoyu Wang
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Bo Li
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100193, China
| | - Qian Zhang
- Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
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Current Aspects on the Pathophysiology of Bone Metabolic Defects during Progression of Scoliosis in Neurofibromatosis Type 1. J Clin Med 2022; 11:jcm11020444. [PMID: 35054138 PMCID: PMC8781800 DOI: 10.3390/jcm11020444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 02/04/2023] Open
Abstract
Neurofibromatosis type 1 (NF1), which is the most common phacomatoses, is an autosomal dominant disorder characterized by clinical presentations in various tissues and organs, such as the skin, eyes and nervous and skeletal systems. The musculoskeletal implications of NF1 include a variety of deformities, including scoliosis, kyphoscoliosis, spondylolistheses, congenital bony bowing, pseudarthrosis and bone dysplasia. Scoliosis is the most common skeletal problem, affecting 10-30% of NF1 patients. Although the pathophysiology of spinal deformities has not been elucidated yet, defects in bone metabolism have been implicated in the progression of scoliotic curves. Measurements of Bone Mineral Density (BMD) in the lumbar spine by using dual energy absorptiometry (DXA) and quantitative computer tomography (QCT) have demonstrated a marked reduction in Z-score and osteoporosis. Additionally, serum bone metabolic markers, such as vitamin D, calcium, phosphorus, osteocalcin and alkaline phosphatase, have been found to be abnormal. Intraoperative and histological vertebral analysis confirmed that alterations of the trabecular microarchitecture are associated with inadequate bone turnover, indicating generalized bone metabolic defects. At the molecular level, loss of function of neurofibromin dysregulates Ras and Transforming Growth factor-β1 (TGF-β1) signaling and leads to altered osteoclastic proliferation, osteoblastic activity and collagen production. Correlation between clinical characteristics and molecular pathways may provide targets for novel therapeutic approaches in NF1.
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Li Y, Zhu M, Lin X, Li J, Yuan Z, Liu Y, Xu H. Autophagy is involved in neurofibromatosis type I gene-modulated osteogenic differentiation in human bone mesenchymal stem cells. Exp Ther Med 2021; 22:1262. [PMID: 34603530 PMCID: PMC8453340 DOI: 10.3892/etm.2021.10697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 07/14/2021] [Indexed: 12/30/2022] Open
Abstract
Neurofibromatosis type I (NF1) is an autosomal dominant genetic disease that is caused by mutations in the NF1 gene. Various studies have previously demonstrated that the mTOR complex 1 signaling pathway is essential for the NF1-modulated osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Additionally, the mTOR signaling pathway plays a notable role in autophagy. The present study hypothesized that NF1 could modulate the osteogenic differentiation of BMSCs by regulating the autophagic activities of BMSCs. In the present study, human BMSCs were cultured in an osteogenic induction medium. The expression of the NF1 gene was either knocked down or overexpressed by transfection with a specific small interfering RNA (siRNA) targeting NF1 or the pcDNA3.0 NF1-overexpression plasmid, respectively. Autophagic activities of BMSCs (Beclin-1, P62, LC3B I, and LC3B II) were determined using western blotting, electron microscopy, acridine orange (AO) staining and autophagic flux/lysosomal detection by fluorescence microscopy. In addition, the autophagy activator rapamycin (RAPA) and inhibitor 3-methyladenine (3-MA) were used to investigate the effects of autophagy on NF1-modulated osteogenic differentiation in BMSCs. Inhibiting NF1 with siRNA significantly decreased the expression levels of autophagy markers Beclin-1 and LC3B-II, in addition to osteogenic differentiation markers osterix, runt-related transcription factor 2 and alkaline phosphatase. By contrast, overexpressing NF1 with pcDNA3.0 significantly increased their levels. Transmission electron microscopy, AO staining and autophagic flux/lysosomal detection assays revealed that the extent of autophagosome formation was significantly decreased in the NF1-siRNA group but significantly increased in the NF1-pcDNA3.0 group when compared with the NC-siRNA and pcDNA3.0 groups, respectively. In addition, the activity of the PI3K/AKT/mTOR pathway [phosphorylated (p)-PI3K, p-AKT, p-mTOR and p-p70S6 kinase] was significantly upregulated in the NF1-siRNA group compared with the NC-siRNA group, and significantly inhibited in the NF1-pcDNA3.0 group, compared with the pcDNA3.0 group. The knockdown effects of NF1-siRNA on the autophagy and osteogenic differentiation of BMSCs were reversed by the autophagy activator RAPA, while the overexpression effects of NF1-pcDNA3.0 on the autophagy and osteogenic differentiation of BMSCs were reversed by the autophagy inhibitor 3-MA. In conclusion, results from the present study suggest at the involvement of autophagy in the NF1-modulated osteogenic differentiation of BMSCs. Furthermore, NF1 may partially regulate the autophagic activity of BMSCs through the PI3K/AKT/mTOR signaling pathway.
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Affiliation(s)
- Yiqiang Li
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Mingwei Zhu
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Xuemei Lin
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Jingchun Li
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Zhe Yuan
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Yanhan Liu
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
| | - Hongwen Xu
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
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Wang W, Wei CJ, Cui XW, Li YH, Gu YH, Gu B, Li QF, Wang ZC. Impacts of NF1 Gene Mutations and Genetic Modifiers in Neurofibromatosis Type 1. Front Neurol 2021; 12:704639. [PMID: 34566848 PMCID: PMC8455870 DOI: 10.3389/fneur.2021.704639] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/15/2021] [Indexed: 12/26/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is a tumor predisposition genetic disorder that directly affects more than 1 in 3,000 individuals worldwide. It results from mutations of the NF1 gene and shows almost complete penetrance. NF1 patients show high phenotypic variabilities, including cafe-au-lait macules, freckling, or other neoplastic or non-neoplastic features. Understanding the underlying mechanisms of the diversities of clinical symptoms might contribute to the development of personalized healthcare for NF1 patients. Currently, studies have shown that the different types of mutations in the NF1 gene might correlate with this phenomenon. In addition, genetic modifiers are responsible for the different clinical features. In this review, we summarize different genetic mutations of the NF1 gene and related genetic modifiers. More importantly, we focus on the genotype–phenotype correlation. This review suggests a novel aspect to explain the underlying mechanisms of phenotypic heterogeneity of NF1 and provides suggestions for possible novel therapeutic targets to prevent or delay the onset and development of different manifestations of NF1.
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Affiliation(s)
- Wei Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cheng-Jiang Wei
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xi-Wei Cui
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue-Hua Li
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi-Hui Gu
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bin Gu
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qing-Feng Li
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhi-Chao Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Pyrimidine Biosynthetic Enzyme CAD: Its Function, Regulation, and Diagnostic Potential. Int J Mol Sci 2021; 22:ijms221910253. [PMID: 34638594 PMCID: PMC8508918 DOI: 10.3390/ijms221910253] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/18/2021] [Accepted: 09/19/2021] [Indexed: 01/10/2023] Open
Abstract
CAD (Carbamoyl-phosphate synthetase 2, Aspartate transcarbamoylase, and Dihydroorotase) is a multifunctional protein that participates in the initial three speed-limiting steps of pyrimidine nucleotide synthesis. Over the past two decades, extensive investigations have been conducted to unmask CAD as a central player for the synthesis of nucleic acids, active intermediates, and cell membranes. Meanwhile, the important role of CAD in various physiopathological processes has also been emphasized. Deregulation of CAD-related pathways or CAD mutations cause cancer, neurological disorders, and inherited metabolic diseases. Here, we review the structure, function, and regulation of CAD in mammalian physiology as well as human diseases, and provide insights into the potential to target CAD in future clinical applications.
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Li Y, Lin X, Zhu M, Xun F, Li J, Yuan Z, Liu Y, Xu H. A mutation in SLC20A2 (c.C1849T) promotes proliferation while inhibiting hypertrophic differentiation in ATDC5 chondrocytes. Bone Joint Res 2020; 9:751-760. [PMID: 33135420 PMCID: PMC7649514 DOI: 10.1302/2046-3758.911.bjr-2020-0112.r1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aims This study aimed to investigate the effect of solute carrier family 20 member 2 (SLC20A2) gene mutation (identified from a hereditary multiple exostoses family) on chondrocyte proliferation and differentiation. Methods ATDC5 chondrocytes were cultured in insulin-transferrin-selenium medium to induce differentiation. Cells were transfected with pcDNA3.0 plasmids with either a wild-type (WT) or mutated (MUT) SLC20A2 gene. The inorganic phosphate (Pi) concentration in the medium of cells was determined. The expression of markers of chondrocyte proliferation and differentiation, the Indian hedgehog (Ihh), and parathyroid hormone-related protein (PTHrP) pathway were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Results The expression of SLC20A2 in MUT group was similar to WT group. The Pi concentration in the medium of cells in MUT group was significantly higher than WT group, which meant the SLC20A2 mutation inhibited Pi uptake in ATDC5 chondrocytes. The proliferation rate of ATDC5 chondrocytes in MUT group was greater than WT group. The expression of aggrecan (Acan), α-1 chain of type II collagen (COL2A1), and SRY-box transcription factor 9 (SOX9) were higher in MUT group than WT group. However, the expression of Runt-related transcription factor 2 (Runx2), α-1 chain of type X collagen (COL10A1), and matrix metallopeptidase 13 (MMP13) was significantly decreased in the MUT group. Similar results were obtained by Alcian blue and Alizarin red staining. The expression of Ihh and PTHrP in MUT group was higher than WT group. An inhibitor (cyclopamine) of Ihh/PTHrP signalling pathway inhibited the proliferation and restored the differentiation of chondrocytes in MUT group. Conclusion A mutation in SLC20A2 (c.C1948T) decreases Pi uptake in ATDC5 chondrocytes. SLC20A2 mutation promotes chondrocyte proliferation while inhibiting chondrocyte differentiation. The Ihh/PTHrP signalling pathway may play an important role in this process. Cite this article: Bone Joint Res 2020;9(11):751–760.
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Affiliation(s)
- YiQiang Li
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - XueMei Lin
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - MingWei Zhu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - FuXing Xun
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - JingChun Li
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Zhe Yuan
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - YanHan Liu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - HongWen Xu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
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Vincent A, Natarajan V, Khetan V, Krishnakumar S, Parameswaran S. Heterozygous retinoblastoma gene mutation compromises in vitro osteogenesis of adipose mesenchymal stem cells - a temporal gene expression study. Exp Cell Res 2020; 396:112263. [PMID: 32890459 DOI: 10.1016/j.yexcr.2020.112263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 12/27/2022]
Abstract
Osteosarcoma (OS) is a bone malignancy affecting children and adolescents. Retinoblastoma (RB) patients with germline RB1 mutations are susceptible to osteosarcoma in the second decade of their life. Several studies, particularly in mice, have revealed a role for RB1 in osteogenesis. Since, there is species specific difference attributed in retinoblastoma tumorigenesis between mice and human, we assumed, it is worthwhile exploring the role of RB1 in osteogenesis and thus onset of osteosarcoma. In this study, we analyzed the temporal gene expression of the osteogenic markers, tumor suppressor genes and hormone receptors associated with growth spurt during in vitro osteogenesis of mesenchymal stem cells derived from orbital adipose tissue of germline RB patients and compared it with those with wild type RB1 gene. Mesenchymal stem cells with the heterozygous RB1 mutation showed reduced expression of RB1 and other tumor suppressor genes and showed deregulation of osteogenic markers which could be an initial step for the onset of osteosarcoma.
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Affiliation(s)
- Ambily Vincent
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be University, Thanjavur, India
| | | | - Vikas Khetan
- Shri Bhagwan Mahavir Vitreoretinal Services, Sankara Nethralaya, Medical Research Foundation, Chennai, India
| | - Subramanian Krishnakumar
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India
| | - Sowmya Parameswaran
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India.
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Tan Q, Wu JY, Liu YX, Liu K, Tang J, Ye WH, Zhu GH, Mei HB, Yang G. The neurofibromatosis type I gene promotes autophagy via mTORC1 signalling pathway to enhance new bone formation after fracture. J Cell Mol Med 2020; 24:11524-11534. [PMID: 32862562 PMCID: PMC7576311 DOI: 10.1111/jcmm.15767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/23/2020] [Accepted: 07/31/2020] [Indexed: 12/13/2022] Open
Abstract
Bone fracture is one of the most common injuries. Despite the high regenerative capacity of bones, failure of healing still occurs to near 10% of the patients. Herein, we aim to investigate the modulatory role of neurofibromatosis type I gene (NF1) to osteogenic differentiation of bone marrow–derived mesenchymal stem cells (BMSCs) and new bone formation after fracture in a rat model. We studied the NF1 gene expression in normal and non‐union bone fracture models. Then, we evaluated how NF1 overexpression modulated osteogenic differentiation of BMSCs, autophagy activity, mTORC1 signalling and osteoclastic bone resorption by qRT‐PCR, Western blot and immunostaining assays. Finally, we injected lentivirus‐NF1 (Lv‐NF1) to rat non‐union bone fracture model and analysed the bone formation process. The NF1 gene expression was significantly down‐regulated in non‐union bone fracture group, indicating NF1 is critical in bone healing process. In the NF1 overexpressing BMSCs, autophagy activity and osteogenic differentiation were significantly enhanced. Meanwhile, the NF1 overexpression inhibited mTORC1 signalling and osteoclastic bone resorption. In rat non‐union bone fracture model, the NF1 overexpression significantly promoted bone formation during fracture healing. In summary, we proved the NF1 gene is critical in non‐union bone healing, and NF1 overexpression promoted new bone formation after fracture by enhancing autophagy and inhibiting mTORC1 signalling. Our results may provide a novel therapeutic clue of promoting bone fracture healing.
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Affiliation(s)
- Qian Tan
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Jiang-Yan Wu
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Yao-Xi Liu
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Kun Liu
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Jin Tang
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Wei-Hua Ye
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Guang-Hui Zhu
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Hai-Bo Mei
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
| | - Ge Yang
- Department of Orthopedic Surgery, The Hunan Children's Hospital, Changsha, China
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Mesenchymal Stem Cell-Specific and Preosteoblast-Specific Ablation of TSC1 in Mice Lead to Severe and Slight Spinal Dysplasia, Respectively. BIOMED RESEARCH INTERNATIONAL 2020; 2020:4572687. [PMID: 32309432 PMCID: PMC7140121 DOI: 10.1155/2020/4572687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/09/2020] [Accepted: 03/09/2020] [Indexed: 12/13/2022]
Abstract
Background TSC1-related signaling plays a pivotal role in intramembranous and endochondral ossification processes during skeletogenesis. This study was aimed at determining the significance of the TSC1 gene at different stages of spinal development. Materials and Methods. TSC1-floxed mice (TSC1flox/flox) were crossed with Prrx1-Cre or BGLAP-Cre transgenic mice or mesenchymal stem cell- and osteoblast-specific TSC1-deficient mice, respectively. Somatic and vertebral differences between WT and Prrx1-TSC1 null mice were examined at 4 weeks after birth. Results No apparent body size abnormalities were apparent in newborn and 4-week- to 2-month-old mice with BGLAP-Cre driver-depleted TSC1. Vertebral and intervertebral discs displayed strong dysplasia in Prrx1-TSC1 null mice. In contrast, vertebrae were only slightly affected, and intervertebral discs from skeletal preparations displayed no apparent changes in BGLAP-TSC1 null mice. Conclusion Our data suggest that the TSC1 gene is crucial for endochondral ossification during postnatal spine development but plays discriminative roles at different stages. Mesenchymal stem cell-specific ablation of TSC1 led to severe spinal dysplasia at early stages of endochondral ossification while osteoblast-specific deletion of TSC1 affected vertebrae slightly and had no detectable effects on intervertebral discs.
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