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Archives of Oral Biology Sep 2023Apert syndrome, an autosomal dominant congenital disorder characterized by craniosynostosis, is caused by a missense mutation (S252W or P253R) in fibroblast growth...
OBJECTIVE
Apert syndrome, an autosomal dominant congenital disorder characterized by craniosynostosis, is caused by a missense mutation (S252W or P253R) in fibroblast growth factor receptor 2 (FGFR2). Exosomes are naturally occurring carriers that deliver nucleic acids, including small interfering RNA (siRNA), to induce gene silencing. This study aimed to develop siRNA-loaded exosomes (Ex-siRNA) to silence the Fgfr2 gain-of-function mutation, thereby inhibiting the increased osteoblastic differentiation caused by the constitutive activation of FGFR2 signaling in calvarial osteoblastic cells isolated from Apert syndrome model mice.
DESIGN
Primary calvarial osteoblast-like cells were isolated from the embryonic calvarial sutures of the Apert syndrome model (Fgfr2) and littermate wild-type mice (Ap-Ob and Wt-Ob, respectively). Exosomes were extracted from the serum of wild-type mice, validated using biomarkers, and used to encapsulate siRNAs. After exosome-mediated siRNA transfection, cells were analyzed under a fluorescence microscope to validate the delivery of Ex-siRNA, followed by western blot and real-time reverse transcription polymerase chain reaction analyses.
RESULTS
After 24 h of Ex-siRNA delivery in both Ap-Ob and Wt-Ob, siRNA-loaded exosome delivery was validated. Moreover, p44/42 mitogen-activated protein kinase (MAPK) phosphorylation, runt-related transcription factor 2 (Runx2), and collagen type 1 alpha 1 (Col1a1) mRNA expression, and alkaline phosphatase (ALP) activity were significantly increased in Ap-Ob. The levels of phospho-p44/42 protein, Runx2, Col1a1, and ALP were significantly decreased after Ex-siRNA transfection but did not affect Wt-Ob.
CONCLUSIONS
These results indicate that exosome-mediated delivery of siRNA targeting Fgfr2 is a potential non-invasive treatment for aberrant FGF/FGFR signaling.
Topics: Mice; Animals; Acrocephalosyndactylia; Core Binding Factor Alpha 1 Subunit; RNA, Small Interfering; Exosomes; Cell Differentiation; Osteoblasts
PubMed: 37348363
DOI: 10.1016/j.archoralbio.2023.105753 -
The Journal of Craniofacial Surgery Oct 2023Saethre-Chotzen syndrome (SCS) is a syndromic craniosynostosis with pathogenic variants in the TWIST1 gene showing a broad phenotypic spectrum. Controversies exist in...
Saethre-Chotzen syndrome (SCS) is a syndromic craniosynostosis with pathogenic variants in the TWIST1 gene showing a broad phenotypic spectrum. Controversies exist in the literature regarding surgical management with single one-stage versus patient-tailored surgery and the related reoperation rate for intracranial hypertension of up to 42%. At our center, SCS patients are offered patient-tailored surgery with single-stage fronto-orbital advancement and remodeling or fronto-orbital advancement and remodeling and posterior distraction in an individually determined order. The authors' database identified 35 confirmed SCS patients between 1999 and 2022. Involved sutures in craniosynostosis were left unicoronal (22.9%), bicoronal (22.9%), sagittal (8.6%), bicoronal and sagittal (5.7%), right unicoronal (2.9%), bicoronal and metopic (2.9%), bicoronal, sagittal and metopic (2.9%), and bilateral lambdoid (2.9%). There was pansynostosis in 8.6% and no craniosynostosis in 14.3% of the patients. Twenty-six patients, 10 females, and 16 males were operated on. Mean age at the first surgery was 1.70 years, and 3.86 years at the second surgery. Eleven of 26 patients had invasive intracranial pressure monitoring. Three patients presented with papilledema before the first surgery and 4 afterward. Four of the 26 operated patients were operated initially elsewhere. The other 22 patients were initially referred to our unit and underwent patient-tailored surgery. Nine of these patients (41%) had a second surgery, and 3 (14%) of them were because of raised intracranial pressure. Seven (27%) of all operated patients had a complication. Median follow-up was 13.98 years (range, 1.85-18.08). Patient-tailored surgery in a specialized center and long-term follow-up allow for a low reoperation rate for intracranial hypertension.
Topics: Male; Female; Humans; Infant; Acrocephalosyndactylia; Reoperation; Craniosynostoses; Skull; Intracranial Hypertension
PubMed: 37226293
DOI: 10.1097/SCS.0000000000009429 -
Genetics Aug 2023TWIST1 is a basic helix-loop-helix (bHLH) transcription factor in humans that functions in mesoderm differentiation. TWIST1 primarily regulates genes as a...
TWIST1 is a basic helix-loop-helix (bHLH) transcription factor in humans that functions in mesoderm differentiation. TWIST1 primarily regulates genes as a transcriptional repressor often through TWIST-Box domain-mediated protein-protein interactions. The TWIST-Box also can function as an activation domain requiring 3 conserved, equidistant amino acids (LXXXFXXXR). Autosomal dominant mutations in TWIST1, including 2 reported in these conserved amino acids (F187L and R191M), lead to craniofacial defects in Saethre-Chotzen syndrome (SCS). Caenorhabditis elegans has a single TWIST1 homolog, HLH-8, that functions in the differentiation of the muscles responsible for egg laying and defecation. Null alleles in hlh-8 lead to severely egg-laying defective and constipated animals due to defects in the corresponding muscles. TWIST1 and HLH-8 share sequence identity in their bHLH regions; however, the domain responsible for the transcriptional activity of HLH-8 is unknown. Sequence alignment suggests that HLH-8 has a TWIST-Box LXXXFXXXR motif; however, its function also is unknown. CRISPR/Cas9 genome editing was utilized to generate a domain deletion and several missense mutations, including those analogous to SCS patients, in the 3 conserved HLH-8 amino acids to investigate their functional role. The TWIST-Box alleles did not phenocopy hlh-8 null mutants. The strongest phenotype detected was a retentive (Ret) phenotype with late-stage embryos in the hermaphrodite uterus. Further, GFP reporters of HLH-8 downstream target genes (arg-1::gfp and egl-15::gfp) revealed tissue-specific, target-specific, and allele-specific defects. Overall, the TWIST-Box in HLH-8 is partially required for the protein's transcriptional activity, and the conserved amino acids contribute unequally to the domain's function.
Topics: Animals; Female; Humans; Acrocephalosyndactylia; Basic Helix-Loop-Helix Transcription Factors; Caenorhabditis elegans; Mutation; Transcription Factors; Twist-Related Protein 1
PubMed: 37067863
DOI: 10.1093/genetics/iyad066 -
Plastic and Reconstructive Surgery Aug 2023CRISPR-Cas genome editing tools are among the most substantial advances in the life sciences in modern history. Single-dose gene therapies to correct pathogenic...
CRISPR-Cas genome editing tools are among the most substantial advances in the life sciences in modern history. Single-dose gene therapies to correct pathogenic mutations have moved quickly from bench to bedside, with several therapeutics designed by CRISPR pioneers entering various stages of clinical investigation. Applications of these genetic technologies are poised to reshape the practice of both medicine and surgery. Many of the most morbid conditions treated by craniofacial surgeons are syndromic craniosynostoses caused by mutations in fibroblast growth factor receptor genes, including Apert, Pfeiffer, Crouzon, and Muenke syndromes. The fact that pathogenic mutations in these genes are recurrent in the majority of affected families presents a unique opportunity to develop "off-the-shelf" gene editing therapies to correct these mutations in affected children. The therapeutic potential of these interventions could reshape pediatric craniofacial surgery, potentially first eliminating the need for midface advancement procedures in affected children.
Topics: Child; Humans; Craniosynostoses; Mutation; Face; Specialties, Surgical; Craniofacial Dysostosis; Acrocephalosyndactylia
PubMed: 36912935
DOI: 10.1097/PRS.0000000000010402 -
Plastic and Reconstructive Surgery Sep 2023Crouzon syndrome is characterized by complex craniosynostosis and midfacial hypoplasia. Where frontofacial monobloc advancement (FFMBA) is indicated, the method of...
BACKGROUND
Crouzon syndrome is characterized by complex craniosynostosis and midfacial hypoplasia. Where frontofacial monobloc advancement (FFMBA) is indicated, the method of distraction used to achieve advancement holds an element of equipoise. This two-center retrospective cohort study quantifies the movements produced by internal or external distraction methods used for FFMBA. Using shape analysis, this study evaluates whether the different distraction forces cause plastic deformity of the frontofacial segment, producing distinct morphologic outcomes.
METHODS
Patients with Crouzon syndrome who underwent FFMBA with internal distraction [Hôpital Necker-Enfants Malades (Paris, France)] or external distraction [Great Ormond Street Hospital for Children (London, United Kingdom)] were compared. Digital Imaging and Communications in Medicine files of preoperative and postoperative computed tomographic scans were converted to three-dimensional bone meshes and skeletal movements were assessed using nonrigid iterative closest point registration. Displacements were visualized using color maps and statistical analysis of the vectors was undertaken.
RESULTS
Fifty-one patients met the strict inclusion criteria. Twenty-five underwent FFMBA with external distraction and 26 with internal distraction. External distraction provides a preferential midfacial advancement, whereas internal distractors produce a more positive movement at the lateral orbital rim. This confers good orbital protection but does not advance the central midface to the same extent. Vector analysis confirmed this to be statistically significant ( P < 0.01).
CONCLUSIONS
Morphologic changes resulting from monobloc surgery differ depending on the distraction technique used. Although the relative merits of internal and external distraction still stand, it may be that external distraction is more suited to addressing the midfacial biconcavity seen in syndromic craniosynostosis.
CLINICAL QUESTION/LEVEL OF EVIDENCE
Therapeutic, III.
Topics: Child; Humans; Retrospective Studies; Osteogenesis, Distraction; Facial Bones; Craniofacial Dysostosis; Craniosynostoses; Acrocephalosyndactylia
PubMed: 36847681
DOI: 10.1097/PRS.0000000000010331 -
The Cleft Palate-craniofacial Journal :... Apr 2024Head and neck positioning is a key element of craniofacial reconstructive surgery and can become challenging when intervention necessitates broad exposure of the...
Head and neck positioning is a key element of craniofacial reconstructive surgery and can become challenging when intervention necessitates broad exposure of the calvarium. We present a case of craniosynostosis secondary to Apert's syndrome requiring anterior and posterior cranial vault access during surgical correction. A modified sphinx position was used that required significant neck extension. The patient had concurrent Chiari I malformation with brain stem compression so intraoperative neuromonitoring (IONM) was used to ensure that there were no negative effects on the neural elements with positioning. This highlights benefits of IONM in a setting not typically associated with its use.
Topics: Humans; Skull; Acrocephalosyndactylia; Craniosynostoses; Arnold-Chiari Malformation
PubMed: 36357356
DOI: 10.1177/10556656221135284 -
The Cleft Palate-craniofacial Journal :... Nov 2023Apert, Crouzon, and Pfeiffer syndromes are common genetic syndromes related to syndromic craniosynostosis (SC), whereby it is a congenital defect that occurs when the...
INTRODUCTION
Apert, Crouzon, and Pfeiffer syndromes are common genetic syndromes related to syndromic craniosynostosis (SC), whereby it is a congenital defect that occurs when the cranial growth is distorted. Identifying cranial angles associated with these 3 syndromes may assist the surgical team to focus on a specific cranial part during the intervention planning, thus optimizing surgical outcomes and reducing potential morbidity.
OBJECTIVE
The aim of this study is to identify the cranial angles, which are associated with Apert, Crouzon, and Pfeiffer syndromes.
METHODS
The cranial computed tomography scan images of 17 patients with SC and 22 control groups aged 0 to 12 years who were treated in the University Malaya Medical Centre were obtained, while 12 angular measurements were attained using the Mimics software. The angular data were then divided into 2 groups (patients aged 0 to 24 months and >24 months). This work proposes a 95% confidence interval (CI) for angular mean to detect the abnormality in patient's cranial growth for the SC syndromes.
RESULTS
The 95% CI of angular mean for the control group was calculated and used as an indicator to confirm the abnormality in patient's cranial growth that is associated with the 3 syndromes. The results showed that there are different cranial angles associated with these 3 syndromes.
CONCLUSIONS
All cranial angles of the patients with these syndromes lie outside the 95% CI of angular mean of control group, indicating the reliability of the proposed CI in the identification of abnormality in the patient's cranial growth.
Topics: Humans; Reproducibility of Results; Craniosynostoses; Skull; Acrocephalosyndactylia; Craniofacial Dysostosis; Syndrome
PubMed: 35711157
DOI: 10.1177/10556656221107524 -
The Cleft Palate-craniofacial Journal :... Aug 2023Saethre-Chotzen syndrome (SCS) is a known craniosynostosis syndrome with a variable presentation of craniofacial and somatic involvement. Congenital coronal... (Review)
Review
Saethre-Chotzen syndrome (SCS) is a known craniosynostosis syndrome with a variable presentation of craniofacial and somatic involvement. Congenital coronal craniosynostosis is most commonly observed in SCS; however, progressive postnatal craniosynostosis of other sutures has been reported. The authors present 2 infants with progressive postnatal craniosynostosis and SCS caused by chromosome 7p deletions including the gene. The evolution of their clinical features and a literature review of patients with syndromic, postnatal progressive craniosynostosis illustrate the importance of longitudinal observation and management of these patients.
Topics: Infant; Humans; Gene Deletion; Twist-Related Protein 1; Acrocephalosyndactylia; Craniosynostoses; Chromosome Deletion; Nuclear Proteins
PubMed: 35354337
DOI: 10.1177/10556656221090844