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Lv Y, Wang Q, Lin C, Zheng X, Zhang Y, Hu X. Overexpression of Fgf18 in cranial neural crest cells recapitulates Pierre Robin sequence in mice. Front Cell Dev Biol 2024; 12:1376814. [PMID: 38694818 PMCID: PMC11061347 DOI: 10.3389/fcell.2024.1376814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/05/2024] [Indexed: 05/04/2024] Open
Abstract
The pivotal role of FGF18 in the regulation of craniofacial and skeletal development has been well established. Previous studies have demonstrated that mice with deficiency in Fgf18 exhibit severe craniofacial dysplasia. Recent clinical reports have revealed that the duplication of chromosome 5q32-35.3, which encompasses the Fgf18 gene, can lead to cranial bone dysplasia and congenital craniosynostosis, implicating the consequence of possible overdosed FGF18 signaling. This study aimed to test the effects of augmented FGF18 signaling by specifically overexpressing the Fgf18 gene in cranial neural crest cells using the Wnt1-Cre;pMes-Fgf18 mouse model. The results showed that overexpression of Fgf18 leads to craniofacial abnormalities in mice similar to the Pierre Robin sequence in humans, including abnormal tongue morphology, micrognathia, and cleft palate. Further examination revealed that elevated levels of Fgf18 activated the Akt and Erk signaling pathways, leading to an increase in the proliferation level of tongue tendon cells and alterations in the contraction pattern of the genioglossus muscle. Additionally, we observed that excessive FGF18 signaling contributed to the reduction in the length of Meckel's cartilage and disrupted the development of condylar cartilage, ultimately resulting in mandibular defects. These anomalies involve changes in several downstream signals, including Runx2, p21, Akt, Erk, p38, Wnt, and Ihh. This study highlights the crucial role of maintaining the balance of endogenous FGF18 signaling for proper craniofacial development and offers insights into potential formation mechanisms of the Pierre Robin sequence.
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Affiliation(s)
| | | | | | | | | | - Xuefeng Hu
- Fujian Key Laboratory of Developmental and Neural Biology, College of Life Sciences, Fujian Normal University, Fuzhou, China
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2
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Richbourg HA, Vidal-García M, Brakora KA, Devine J, Takenaka R, Young NM, Gong SG, Neves A, Hallgrímsson B, Marcucio RS. Dosage-dependent effects of FGFR2 W290R mutation on craniofacial shape and cellular dynamics of the basicranial synchondroses. Anat Rec (Hoboken) 2024. [PMID: 38409943 DOI: 10.1002/ar.25398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 12/31/2023] [Accepted: 01/17/2024] [Indexed: 02/28/2024]
Abstract
Craniosynostosis is a common yet complex birth defect, characterized by premature fusion of the cranial sutures that can be syndromic or nonsyndromic. With over 180 syndromic associations, reaching genetic diagnoses and understanding variations in underlying cellular mechanisms remains a challenge. Variants of FGFR2 are highly associated with craniosynostosis and warrant further investigation. Using the missense mutation FGFR2W290R , an effective mouse model of Crouzon syndrome, craniofacial features were analyzed using geometric morphometrics across developmental time (E10.5-adulthood, n = 665 total). Given the interrelationship between the cranial vault and basicranium in craniosynostosis patients, the basicranium and synchondroses were analyzed in perinates. Embryonic time points showed minimal significant shape differences. However, hetero- and homozygous mutant perinates and adults showed significant differences in shape and size of the cranial vault, face, and basicranium, which were associated with cranial doming and shortening of the basicranium and skull. Although there were also significant shape and size differences associated with the basicranial bones and clear reductions in basicranial ossification in cleared whole-mount samples, there were no significant alterations in chondrocyte cell shape, size, or orientation along the spheno-occipital synchondrosis. Finally, shape differences in the cranial vault and basicranium were interrelated at perinatal stages. These results point toward the possibility that facial shape phenotypes in craniosynostosis may result in part from pleiotropic effects of the causative mutations rather than only from the secondary consequences of the sutural defects, indicating a novel direction of research that may shed light on the etiology of the broad changes in craniofacial morphology observed in craniosynostosis syndromes.
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Affiliation(s)
- Heather A Richbourg
- Department of Orthopedic Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Marta Vidal-García
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
- The McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Katherine A Brakora
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
| | - Jay Devine
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
- The McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Risa Takenaka
- Department of Orthopedic Surgery, University of California, San Francisco, San Francisco, California, USA
- Molecular and Cellular Biology, University of Washington, Seattle, Washington, USA
| | - Nathan M Young
- Department of Orthopedic Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Siew-Ging Gong
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Amanda Neves
- The McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- DeepSurfaceAI, Calgary, Alberta, Canada
| | - Benedikt Hallgrímsson
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
- The McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ralph S Marcucio
- Department of Orthopedic Surgery, University of California, San Francisco, San Francisco, California, USA
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3
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Jones E, McLaughlin KA. A Novel Perspective on Neuronal Control of Anatomical Patterning, Remodeling, and Maintenance. Int J Mol Sci 2023; 24:13358. [PMID: 37686164 PMCID: PMC10488252 DOI: 10.3390/ijms241713358] [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: 07/20/2023] [Revised: 08/14/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
While the nervous system may be best known as the sensory communication center of an organism, recent research has revealed a myriad of multifaceted roles for both the CNS and PNS from early development to adult regeneration and remodeling. These systems work to orchestrate tissue pattern formation during embryonic development and continue shaping pattering through transitional periods such as metamorphosis and growth. During periods of injury or wounding, the nervous system has also been shown to influence remodeling and wound healing. The neuronal mechanisms responsible for these events are largely conserved across species, suggesting this evidence may be important in understanding and resolving many human defects and diseases. By unraveling these diverse roles, this paper highlights the necessity of broadening our perspective on the nervous system beyond its conventional functions. A comprehensive understanding of the complex interactions and contributions of the nervous system throughout development and adulthood has the potential to revolutionize therapeutic strategies and open new avenues for regenerative medicine and tissue engineering. This review highlights an important role for the nervous system during the patterning and maintenance of complex tissues and provides a potential avenue for advancing biomedical applications.
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Affiliation(s)
| | - Kelly A. McLaughlin
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA;
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4
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Mechanical loading of cranial joints minimizes the craniofacial phenotype in Crouzon syndrome. Sci Rep 2022; 12:9693. [PMID: 35690633 PMCID: PMC9188582 DOI: 10.1038/s41598-022-13807-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/27/2022] [Indexed: 11/09/2022] Open
Abstract
Children with syndromic forms of craniosynostosis undergo a plethora of surgical interventions to resolve the clinical features caused by the premature fusion of cranial sutures. While surgical correction is reliable, the need for repeated rounds of invasive treatment puts a heavy burden on the child and their family. This study explores a non-surgical alternative using mechanical loading of the cranial joints to prevent or delay craniofacial phenotypes associated with Crouzon syndrome. We treated Crouzon syndrome mice before the onset of craniosynostosis by cyclical mechanical loading of cranial joints using a custom designed set-up. Cranial loading applied to the frontal bone partially restores normal skull morphology, significantly reducing the typical brachycephalic appearance. This is underpinned by the delayed closure of the coronal suture and of the intersphenoidal synchondrosis. This study provides a novel treatment alternative for syndromic craniosynostosis which has the potential to be an important step towards replacing, reducing or refining the surgical treatment of all craniosynostosis patients.
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5
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Pitirri MK, Durham EL, Romano NA, Santos JI, Coupe AP, Zheng H, Chen DZ, Kawasaki K, Jabs EW, Richtsmeier JT, Wu M, Motch Perrine SM. Meckel's Cartilage in Mandibular Development and Dysmorphogenesis. Front Genet 2022; 13:871927. [PMID: 35651944 PMCID: PMC9149363 DOI: 10.3389/fgene.2022.871927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/15/2022] [Indexed: 12/02/2022] Open
Abstract
The Fgfr2cC342Y/+ Crouzon syndrome mouse model carries a cysteine to tyrosine substitution at amino acid position 342 (Cys342Tyr; C342Y) in the fibroblast growth factor receptor 2 (Fgfr2) gene equivalent to a FGFR2 mutation commonly associated with Crouzon and Pfeiffer syndromes in humans. The Fgfr2c C342Y mutation results in constitutive activation of the receptor and is associated with upregulation of osteogenic differentiation. Fgfr2cC342Y/+ Crouzon syndrome mice show premature closure of the coronal suture and other craniofacial anomalies including malocclusion of teeth, most likely due to abnormal craniofacial form. Malformation of the mandible can precipitate a plethora of complications including disrupting development of the upper jaw and palate, impediment of the airway, and alteration of occlusion necessary for proper mastication. The current paradigm of mandibular development assumes that Meckel’s cartilage (MC) serves as a support or model for mandibular bone formation and as a template for the later forming mandible. If valid, this implies a functional relationship between MC and the forming mandible, so mandibular dysmorphogenesis might be discerned in MC affecting the relationship between MC and mandibular bone. Here we investigate the relationship of MC to mandible development from the early mineralization of the mandible (E13.5) through the initiation of MC degradation at E17.7 using Fgfr2cC342Y/+ Crouzon syndrome embryos and their unaffected littermates (Fgfr2c+/+). Differences between genotypes in both MC and mandibular bone are subtle, however MC of Fgfr2cC342Y/+ embryos is generally longer relative to unaffected littermates at E15.5 with specific aspects remaining relatively large at E17.5. In contrast, mandibular bone is smaller overall in Fgfr2cC342Y/+ embryos relative to their unaffected littermates at E15.5 with the posterior aspect remaining relatively small at E17.5. At a cellular level, differences are identified between genotypes early (E13.5) followed by reduced proliferation in MC (E15.5) and in the forming mandible (E17.5) in Fgfr2cC342Y/+ embryos. Activation of the ERK pathways is reduced in the perichondrium of MC in Fgfr2cC342Y/+ embryos and increased in bone related cells at E15.5. These data reveal that the Fgfr2c C342Y mutation differentially affects cells by type, location, and developmental age indicating a complex set of changes in the cells that make up the lower jaw.
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Affiliation(s)
- M Kathleen Pitirri
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Emily L Durham
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Natalie A Romano
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Jacob I Santos
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Abigail P Coupe
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Hao Zheng
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Danny Z Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Kazuhiko Kawasaki
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Ethylin Wang Jabs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Joan T Richtsmeier
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
| | - Meng Wu
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Susan M Motch Perrine
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States
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6
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Torii D, Kobayashi T, Horie T, Tsutsui TW. Characterization of dental pulp stem cells isolated from a patient diagnosed with Crouzon syndrome. J Cell Physiol 2021; 236:5317-5324. [PMID: 33386632 PMCID: PMC8048801 DOI: 10.1002/jcp.30241] [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: 02/17/2020] [Revised: 11/26/2020] [Accepted: 12/09/2020] [Indexed: 01/09/2023]
Abstract
Stem cells isolated from patients with rare diseases are important to elucidate their pathogeny and mechanisms to enable regenerative therapy. However, the mechanisms underlying tissue regeneration using patient‐derived dental pulp stem cells (DPSCs) are unclear. In this study, we investigated the levels of mRNA and protein expression related to cellular differentiation of Crouzon syndrome patient‐derived DPSCs (CS‐DPSCs) with a Gly338Arg fibroblast growth factor receptor 2 mutation. Multipotency‐related gene expression levels were equivalent in both healthy donor DPSCs and CS‐DPSCs. CS‐DPSCs showed higher osteocalcin (OCN) expression than healthy donor DPSCs. CS‐DPSCs showed a lower increase in the rate of OCN expression among phorbol 12‐myristate 13‐acetate (PMA)‐treated cells than healthy donor DPSCs compared with untreated control cells. CS‐DPSCs showed a lower phosphorylation rate of p38 and p44/42 in PMA‐treated cells than healthy donor DPSCs compared with untreated control cells. These results demonstrate that CS‐DPSCs have higher OCN expression and lower PMA stimulation‐responsiveness than healthy donor DPSCs.
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Affiliation(s)
- Daisuke Torii
- Department of Pharmacology, The Nippon Dental University School of Life Dentistry, Tokyo, Japan
| | - Tomoko Kobayashi
- Research Center for Odontology, The Nippon Dental University School of Life Dentistry, Tokyo, Japan.,Department of Developmental and Regenerative Dentistry, The Nippon Dental University School of Life Dentistry, Tokyo, Japan
| | - Tetsuro Horie
- Research Center for Odontology, The Nippon Dental University School of Life Dentistry, Tokyo, Japan.,Department of Oral Health, The Nippon Dental University School of Life Dentistry, Tokyo, Japan
| | - Takeo W Tsutsui
- Department of Pharmacology, The Nippon Dental University School of Life Dentistry, Tokyo, Japan
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7
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Genetic background dependent modifiers of craniosynostosis severity. J Struct Biol 2020; 212:107629. [PMID: 32976998 DOI: 10.1016/j.jsb.2020.107629] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/13/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
Craniosynostosis severity varies in patients with identical genetic mutations. To understand causes of this phenotypic variation, we backcrossed the FGFR2+/C342Y mouse model of Crouzon syndrome onto congenic C57BL/6 and BALB/c backgrounds. Coronal suture fusion was observed in C57BL/6 (88% incidence, p < .001 between genotypes) but not in BALB/c FGFR2+/C342Y mutant mice at 3 weeks after birth, establishing that that the two models differ in phenotype severity. To begin identifying pre-existing modifiers of craniosynostosis severity, we compared transcriptome signatures of cranial tissues from C57BL/6 vs. BALB/c FGFR2+/+ mice. We separately analyzed frontal bone with coronal suture tissue from parietal bone with sagittal suture tissues because the coronal suture but not the sagittal suture fuses in FGFR2+/C342Y mice. The craniosynostosis associated Twist and En1 transcription factors were down-regulated, while Runx2 was up-regulated, in C57BL/6 compared to BALB/c tissues, which could predispose to craniosynostosis. Transcriptome analyses under the GO term MAPK cascade revealed that genes associated with calcium ion channels, angiogenesis, protein quality control and cell stress response were central to transcriptome differences associated with genetic background. FGFR2 and HSPA2 protein levels plus ERK1/2 activity were higher in cells isolated from C57BL/6 than BALB/c cranial tissues. Notably, the HSPA2 protein chaperone is central to craniofacial genetic epistasis, and we find that FGFR2 protein is abnormally processed in primary cells from FGFR2+/C342Y but not FGFR2+/+ mice. Therefore, we propose that differences in protein quality control responses may contribute to genetic background influences on craniosynostosis phenotype severity.
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8
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Siismets EM, Hatch NE. Cranial Neural Crest Cells and Their Role in the Pathogenesis of Craniofacial Anomalies and Coronal Craniosynostosis. J Dev Biol 2020; 8:jdb8030018. [PMID: 32916911 PMCID: PMC7558351 DOI: 10.3390/jdb8030018] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/01/2020] [Accepted: 09/07/2020] [Indexed: 12/29/2022] Open
Abstract
Craniofacial anomalies are among the most common of birth defects. The pathogenesis of craniofacial anomalies frequently involves defects in the migration, proliferation, and fate of neural crest cells destined for the craniofacial skeleton. Genetic mutations causing deficient cranial neural crest migration and proliferation can result in Treacher Collins syndrome, Pierre Robin sequence, and cleft palate. Defects in post-migratory neural crest cells can result in pre- or post-ossification defects in the developing craniofacial skeleton and craniosynostosis (premature fusion of cranial bones/cranial sutures). The coronal suture is the most frequently fused suture in craniosynostosis syndromes. It exists as a biological boundary between the neural crest-derived frontal bone and paraxial mesoderm-derived parietal bone. The objective of this review is to frame our current understanding of neural crest cells in craniofacial development, craniofacial anomalies, and the pathogenesis of coronal craniosynostosis. We will also discuss novel approaches for advancing our knowledge and developing prevention and/or treatment strategies for craniofacial tissue regeneration and craniosynostosis.
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Affiliation(s)
- Erica M. Siismets
- Oral Health Sciences PhD Program, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA;
| | - Nan E. Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA
- Correspondence: ; Tel.: +1-734-647-6567
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9
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Hasan MR, Takatalo M, Ma H, Rice R, Mustonen T, Rice DP. RAB23 coordinates early osteogenesis by repressing FGF10-pERK1/2 and GLI1. eLife 2020; 9:55829. [PMID: 32662771 PMCID: PMC7423339 DOI: 10.7554/elife.55829] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Mutations in the gene encoding Ras-associated binding protein 23 (RAB23) cause Carpenter Syndrome, which is characterized by multiple developmental abnormalities including polysyndactyly and defects in skull morphogenesis. To understand how RAB23 regulates skull development, we generated Rab23-deficient mice that survive to an age where skeletal development can be studied. Along with polysyndactyly, these mice exhibit premature fusion of multiple sutures resultant from aberrant osteoprogenitor proliferation and elevated osteogenesis in the suture. FGF10-driven FGFR1 signaling is elevated in Rab23-/-sutures with a consequent imbalance in MAPK, Hedgehog signaling and RUNX2 expression. Inhibition of elevated pERK1/2 signaling results in the normalization of osteoprogenitor proliferation with a concomitant reduction of osteogenic gene expression, and prevention of craniosynostosis. Our results suggest a novel role for RAB23 as an upstream negative regulator of both FGFR and canonical Hh-GLI1 signaling, and additionally in the non-canonical regulation of GLI1 through pERK1/2.
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Affiliation(s)
- Md Rakibul Hasan
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Maarit Takatalo
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Hongqiang Ma
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Ritva Rice
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Tuija Mustonen
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - David Pc Rice
- Craniofacial Development and Malformations research group, Orthodontics, Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.,Oral and Maxillofacial Diseases, Helsinki University Hospital, Helsinki, Finland
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10
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Jiang Q, Mei L, Zou Y, Ding Q, Cannon R, Chen H, Li H. Genetic Polymorphisms in FGFR2 Underlie Skeletal Malocclusion. J Dent Res 2019; 98:1340-1347. [DOI: 10.1177/0022034519872951] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Fibroblast growth factor receptor 2 ( FGFR2) in craniofacial bones mediates osteoprogenitor proliferation, differentiation, and apoptosis. The distortion of proper craniofacial bone growth may cause class II and class III skeletal malocclusion and result in compromised function and aesthetics. Here, we investigated the association between variations in FGFR2 and skeletal malocclusions. First, 895 subjects were included in a 2-stage case-control study with independent populations (stage 1: n = 138 class I, 111 class II, and 81 class III; stage 2: n = 279 class I, 187 class II, and 99 class III). Eight candidate single-nucleotide polymorphisms (SNPs) in FGFR2 were screened and validated. Five SNPs (rs2162540, rs2981578, rs1078806, rs11200014, and rs10736303) were found to be associated with skeletal malocclusions (all P < 0.05). That is, rs2162540 was significantly associated with skeletal class II malocclusion, while others were associated with skeletal class III malocclusion. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis showed that the common genotypes of rs2981578 and rs10736303 contained the binding sites of RUNX2 and SMAD4. Compared with the common genotypes, the minor genotypes at these 2 SNPs decreased the binding affinity and enhancer effect of RUNX2 and SMAD4, as well the levels of FGFR2 expression. In addition, FGFR2 expression contributed positively to osteogenic differentiation in vitro. Thus, we identified FGFR2 as a skeletal malocclusion risk gene, and FGFR2 polymorphisms regulated its transcriptional expression and then osteogenic differentiation.
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Affiliation(s)
- Q. Jiang
- Orthodontic Department, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - L. Mei
- Department of Oral Sciences, Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Y. Zou
- Nanjing University School of Medicine, Nanjing, China
| | - Q. Ding
- Nanjing University School of Medicine, Nanjing, China
| | - R.D. Cannon
- Department of Oral Sciences, Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - H. Chen
- Nanjing University School of Medicine, Nanjing, China
| | - H. Li
- Orthodontic Department, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
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