Development Of Craniofacial Skeleton Research Articles

Tmem88 plays an essential role in pharyngeal pouch progenitor specification by inhibiting Wnt/β-catenin signaling

Abstract Pharyngeal pouches, which are endodermal outpockets that segment the pharyngeal arches, play a crucial role in the development of craniofacial skeletons in vertebrate embryos. Our previous study successfully identified pharyngeal pouch progenitors (PPPs) in zebrafish embryos and emphasized the significance of BMP2b signaling in their specification. However, the specific mechanism by which these progenitors originate from endodermal cells remains largely unknown. Here we found that the pharmacological activation of Wnt signaling pathway disrupts the emergence of PPPs and subsequently hinders the formation of pharyngeal pouches. Moreover, we have identified the expression of tmem88a and tmem88b (collectively known as tmem88a/b) in PPPs during the early-somite stages. Furthermore, the deficiency of tmem88a/b leads to an excessive accumulation of β-catenin in both the cytoplasm and nucleus of endodermal cells that are intended to differentiate into PPPs. Importantly, suppressing the hyperactivation of Wnt/β-catenin signaling through pharmacological treatment, the defects in PPP specification in tmem88a/b−/− mutants are successfully rescued. In summary, our findings establish a clear connection between the specification of PPPs and the regulation of Wnt signaling mediated by Tmem88. These results underscore the pivotal role of Tmem88 in the development of pharyngeal pouches.

The Impact of Benign Jawbone Tumors on the Temporomandibular Joint and Occlusion in Children: A Ten-Year Follow-Up Study

This study aimed to provide a complex analysis of the modifications in craniofacial skeleton development that may arise following the diagnosis of pediatric benign jaw tumors. A prospective study was undertaken involving 53 patients younger than 18 years of age, who presented for treatment at the Department of Maxillo-Facial Surgery, University of Medicine and Pharmacy, Cluj-Napoca, with a primary benign jaw lesion between 2012 and 2022. A total of 28 odontogenic cysts (OCs), 14 odontogenic tumors (OTs), and 11 non-OTs were identified. At follow-up, dental anomalies were identified in 26 patients, and overjet changes were found in 33 children; lateral crossbite, midline shift, and edge-to-edge bite were found in 49 cases; deep or open bite were found in 23 patients. Temporomandibular disorders (TMDs) were found in 51 children, with unilateral TMJ changes identified in 7 cases and bilateral modifications found in 44 patients. Degenerative changes in the TMJ were also diagnosed in 22 pediatric patients. Although benign lesions could be associated with dental malocclusions, a direct etiological factor could be not identified. The presence of jaw tumors or their surgical treatment could, however, be linked to a change of the occlusal relationships or the onset of a TMD.

Inhalational Induction: A Safe Anaesthetic Management in a Patient with Crouzon Syndrome.

Crouzon syndrome is a rare genetic disorder involving craniofacial skeleton development. It's characterized by a triad of cranial deformities: premature craniosynostosis, facial anomalies (mid-facial hypoplasia), and exophthalmia. The anaesthetic management challenges include the presence of a difficult airway, history of obstructive sleep apnea, congenital cardiac disorders, hypothermia, blood loss, and venous air embolism. We present the case of an infant with Crouzon syndrome who was scheduled for a ventriculoperitoneal shunt placement managed with inhalational induction.

Muscle insulin-like growth factor-I modulates murine craniofacial bone growth.

Insulin-like growth factor I (IGF-I) is essential for muscle and bone development and a primary mediator of growth hormone (GH) actions. While studies have elucidated the importance of IGF-I specifically in muscle or bone development, few studies to date have evaluated the relationship between muscle and bone modulated by IGF-I in vivo, during post-natal growth. Mice with muscle-specific IGF-I overexpression (mIgf1+/+) were utilised to determine IGF-I- and muscle-mass-dependent effects on craniofacial skeleton development during post-natal growth. mIgf1+/+ mice displayed accelerated craniofacial bone growth when compared to wild-type animals. Virus-mediated expression of IGF-I targeting the masseter was performed to determine if post-natal modulation of IGF-I altered mandibular structures. Increased IGF-I in the masseter affected the mandibular base plane angle in a lateral manner, increasing the width of the mandible. At the cellular level, increased muscle IGF-I also accelerated cartilage thickness in the mandibular condyle. Importantly, mandibular length changes associated with increased IGF-I were not present in mice with genetic inhibition of muscle IGF-I receptor activity. These results demonstrated that muscle IGF-I could indirectly affect craniofacial growth through IGF-I-dependent increases in muscle hypertrophy. These findings have clinical implications when considering IGF-I as a therapeutic strategy for craniofacial disorders.

Trps1 Regulates Development of Craniofacial Skeleton and Is Required for the Initiation of Palatal Shelves Fusion.

Trichorhinophalangeal syndrome (TRPS) is an autosomal dominant disorder resulting from heterozygous mutations of the TRPS1 gene. Common craniofacial abnormalities in TRPS patients include micrognathia, hypoplastic zygomatic arch, high-arched palate, and, occasionally, cleft palate. Studies have demonstrated that mice with a heterozygous Trps1 mutation (Trps1+/− mice) have similar features to patients with TRPS, including high-arched palates. However, mice with a homozygous Trps1 mutation (Trps1−/− mice) exhibit similar but more severe abnormalities, including cleft palate. Our study aimed to characterize the craniofacial phenotype to understand the role of Trps1 in craniofacial development and gain insight on the cleft palate pathogenesis in Trps1 deficiency. Whole-mount skeletal staining revealed hypoplastic skeletal and cartilaginous elements, steep nasal slope, and missing presphenoid in Trps1−/− mice. Although several craniofacial skeleton elements were abnormal in Trps1−/− mice, the Trps1 deficiency did not appear to disrupt cranial vault development. All Trps1−/− mice presented with cleft palate. Analyses of Trps1 expression during palatogenesis detected Trps1 mRNA and protein in palatal mesenchyme and in specific regions of palatal epithelium, which suggested that Trps1 is involved in palatal fusion. Ex vivo culture experiments demonstrated that Trps1−/− palatal shelves were unable to initiate the fusion process. On the molecular level, Trps1 deficiency resulted in decreased epithelial expression of proteins involved in palatal fusion, including chondroitin sulfate proteoglycan, transforming growth factor-beta 3, Twist1, and beta-catenin. Mesenchymal expression of chondroitin sulfate proteoglycan expression was unaffected, indicating a cell type-specific mechanism of Trps1 regulation on chondroitin sulfate proteoglycan. In conclusion, we demonstrated that Trps1 is involved in the development of craniofacial skeletal elements and in the initiation of the palatal shelves fusion. Furthermore, our studies uncovered that Trps1 is required for epithelial expression of several proteins involved in the palatal shelves fusion.

Shaping the craniofacial skeleton of Mexican cavefish (Astyanax mexicanus); Role of Osteoblast and Osteoclast

The vertebrate bony skeleton is remodelled continuously by bone deposition and reabsorption, which is essential for normal development, growth, repair and for the mineral homeostasis. Remodelling of the skeleton usually involves the removal of the bone by osteoclasts and the subsequent formation of new bone by osteoblasts. These remodelling mechanisms can be found in the teleost fish skeleton with special adaptation to the aquatic life. Most of the fish species have teeth in their craniofacial region and replace their dentitions though out the life which lead to continuous bone remodelling activity in the tooth‐bearing bones. The Mexican tetra (Astyanax mexicanus), is a small teleost fish that exists as two morphs; sighted and blind cave form. The degeneration of the eyes, result in the characteristics craniofacial phenotype in cavefish. However, little is known about the cellular mechanisms underlying the remodelling activity of the skeleton of this species. This study was designed to identify the cellular interactions during the development of craniofacial skeleton of Mexican cavefish. Histological and whole mount analysis was performed to compare the development of the skeleton in these two morphs. The cavefish showed delayed eruption of teeth in tooth‐bearing bones but has large jaw bones compared to the surface larval fish. Sites of bone resorption in the bony skeleton will be investigated by RNA in situ hybridization and ultrastructural analysis. Live bone staining techniques will be used to identify the pattern of bone deposition. This study will provide insights into the evolution of osteoblastic and osteoclastic cell activity and will highlight the use of this species as a model in mammalian skeletal disorders.Support or Funding InformationThis research was funded by the University of Manitoba.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The E3 ubiquitin ligase WWP2 facilitates RUNX2 protein transactivation in a mono-ubiquitination manner during osteogenic differentiation

Poly-ubiquitination-mediated RUNX2 degradation is an important cause of age- and inflammation-related bone loss. NEDD4 family E3 ubiquitin protein ligases are thought to be the major regulators of RUNX2 poly-ubiquitination. However, we observed a mono-ubiquitination of RUNX2 that was catalyzed by WWP2, a member of the NEDD4 family of E3 ubiquitin ligases. WWP2 has been reported to catalyze the mono-ubiquitination of Goosecoid in chondrocytes, facilitating craniofacial skeleton development. In this study, we found that osteogenic differentiation of mesenchymal stem cells promoted WWP2 expression and nuclear accumulation. Knockdown of Wwp2 in mesenchymal stem cells and osteoblasts led to significant deficiencies of osteogenesis, including decreased mineral deposition and down-regulation of osteogenic marker genes. Co-immunoprecipitation experiments showed the interaction of WWP2 with RUNX2 in vitro and in vivo Mono-ubiquitination by WWP2 leads to RUNX2 transactivation, as evidenced by the wild type of WWP2, but not its ubiquitin ligase-dead mutant, augmenting RUNX2-reponsive reporter activity. Moreover, deletion of WWP2-dependent mono-ubiquitination resulted in striking defects of RUNX2 osteoblastic activity. In addition, ectopic expression of the constitutively active type 1A bone morphogenetic protein receptor enhanced WWP2-dependent RUNX2 ubiquitination and transactivation, demonstrating a regulatory role of bone morphogenetic protein signaling in the WWP2-RUNX2 axis. Taken together, our results provide evidence that WWP2 serves as a positive regulator of osteogenesis by augmenting RUNX2 transactivation in a non-proteolytic mono-ubiquitination manner.

The Role of Sonic Hedgehog in Craniofacial Patterning, Morphogenesis and Cranial Neural Crest Survival.

Craniofacial defects (CFD) are a significant healthcare problem worldwide. Understanding both the morphogenetic movements which underpin normal facial development, as well as the molecular factors which regulate these processes, forms the cornerstone of future diagnostic, and ultimately, preventative therapies. The soluble morphogen Sonic hedgehog (Shh), a vertebrate orthologue of Drosophila hedgehog, is a key signalling factor in the regulation of craniofacial skeleton development in vertebrates, operating within numerous tissue types in the craniofacial primordia to spatiotemporally regulate the formation of the face and jaws. This review will provide an overview of normal craniofacial skeleton development, and focus specifically on the known roles of Shh in regulating the development and progression of the first pharyngeal arch, which in turn gives rise to both the upper jaw (maxilla) and lower jaw (mandible).

ADAM10 is essential for cranial neural crest-derived maxillofacial bone development

Growth disorders of the craniofacial bones may lead to craniofacial deformities. The majority of maxillofacial bones are derived from cranial neural crest cells via intramembranous bone formation. Any interruption of the craniofacial skeleton development process might lead to craniofacial malformation. A disintegrin and metalloprotease (ADAM)10 plays an essential role in organ development and tissue integrity in different organs. However, little is known about its function in craniofacial bone formation. Therefore, we investigated the role of ADAM10 in the developing craniofacial skeleton, particularly during typical mandibular bone development. First, we showed that ADAM10 was expressed in a specific area of the craniofacial bone and that the expression pattern dynamically changed during normal mouse craniofacial development. Then, we crossed wnt1-cre transgenic mice with adam10-flox mice to generate ADAM10 conditional knockout mice. The stereomicroscopic, radiographic, and von Kossa staining results showed that conditional knockout of ADAM10 in cranial neural crest cells led to embryonic death, craniofacial dysmorphia and bone defects. Furthermore, we demonstrated that impaired mineralization could be triggered by decreased osteoblast differentiation, increased cell death. Overall, these findings show that ADAM10 plays an essential role in craniofacial bone development.

Radiological and clinical difficulties in the management of chronic maxillary sinusitis in β Thalassemic paediatric patients

IntroductionBeta thalassemia is a blood dyscrasia that caused a marked expansion of active marrow spaces and extramedullary haematopoiesis results. In these patients various alterations and abnormalities affects different body areas, including increased risk of sinusitis. The marrow expansion in the facial bones results in delay in pneumatisation of the sinuses, overgrowth of the maxillae, and forward displacement of the upper incisors with skeletal deformities.In current literature, maxillary sinuses are not deeply evaluated by CT scan studies in these kind of patients.The aim of our study was to investigate the presence of maxillary sinuses abnormalities by the use of CT in patients with beta-thalassemia major and to compare these findings with a control group free from this disease. Materials and methodsA retrospective analysis of 22 paediatric patients with beta-thalassemia major and 22 control subjects without sinonasal diseases was performed. CT was done using a 64-multidetector-row CT scanner without contrast injection, obtained in axial plane using thin-slice technique. Evaluated parameters were: bone thickness of the lateral and anterior wall, density and volume of the maxillary sinuses. ResultsSignificant difference was found between the study group and control group in the evaluation of all the parameters examined. The maxillary sinus of β thalassemic patients was smaller respect of controls, the bone was more dense and thick in the side and anterior wall. Beta-thalassemic patients have a relative risk of 2.87 to develop a maxillary sinusitis. DiscussionIn these patients there is an increased incidence of sinonasal infections due to the abnormal development of cranio facial skeleton. These bone alterations might confuse the physicians and lead to an increased rate of sinusitis diagnoses.

The dentist's role in diagnosing craniofacial dysostosis

Introduction: The Crouzon syndrome is a rare clinical condition that affects the craniofacial skeleton development. It accounts for about 4.8% of all the cases of craniosynostosis, and it is the most common syndrome presenting with craniosynostoses. The Crouzon syndrome’s early diagnosis is critical to avoid cranial hypertension as well as visual disturbances and blindness. Children who have Crouzon syndrome have a range of problems of variable severity, from mild facial defects causing a primarily cosmetic concern, to severe symptoms affecting breathing, feeding, vision and brain development. The dental profession should have sufficient knowledge of syndromes associated with dysmorphic facies to detect patients who are unaware of their condition. Case Report: A 23­year­old female patient presented to the clinic with multiple dental problems affecting masticatory efficiency and esthetics. On observation, it was seen that she had many facial and dental deformities which were suggestive of craniofacial dysostosis. The case was diagnosed as Crouzon syndrome. Conclusion: This case report emphasizes the role of a dentist in diagnosing such conditions and coordinating a multi­disciplinary team for corrective measures.

Visualization of skeletons and intervertebral disks in live fish larvae by fluorescent calcein staining and disk specific GFP expression

Zebrafish and medaka have become popular models for studying skeletal development because of high fecundity, shorter generation period, and transparency of fish embryo. The first step to study skeletal development is visualizing bone and cartilage. Live animal staining with fluorescent calcein have several advantages over the standard skeletal staining protocol by using alizarin red and alcian blue for bone and cartilage. However, there is no detailed study examining skeletal development of live marine fish larvae by calcein staining. Here we applied calcein staining to examine skeletal development in red sea bream larvae. In addition, green fluorescent protein (GFP) reporter zebrafish was employed to trace lineage analysis of intervertebral disk cells in live fish larvae. Calcein staining of red sea bream larvae successfully visualized development of craniofacial skeletons as well as urinary calculus. Histochemical detection of alkaline phosphatase (ALP) activity revealed that abnormal segmentation of notochord induced by RA during vertebral development in zebrafish. Immunohistochemistry clearly revealed that GFP-positive cells in intervertebral space was nucleus polposus like cell in twhh-GFP transgenic zebrafish. It was demonstrated usefulness of calcein and ALP staining and twhh-GFP transgenic zebrafish for studying skeletal development in live fish larvae.

Prdm1a is necessary for posterior pharyngeal arch development in zebrafish

Multiple tissue interactions and signaling within the pharyngeal arches are required for development of the craniofacial skeleton. Here, we focus on the role of the transcription factor prdm1a in the differentiation of the posterior skeleton. prdm1a is expressed in the presumptive pharyngeal arch region and later in an endodermal pouch, the otic vesicle, and pharyngeal teeth. prdm1a mutants display a reduction in pharyngeal arch markers, a loss of posterior ceratobranchial cartilages, and a reduction in most neural crest-derived dermal bones. This is likely caused by a decrease in the number of proliferating cells but not an increase in cell death. Finally, a reduction in two key developmental signaling pathways, Fgf and retinoic acid, alters prdm1a expression, suggesting that prdm1a expression is mediated by these signaling pathways to pattern the posterior craniofacial skeleton. Together, these results indicate an essential role for prdm1a in the development of the zebrafish craniofacial skeleton.

Effect of Maternal Lead Exposure on Craniofacial Ossification in Rat Fetuses and the Role of Antioxidant Therapy

Lead exposure during intrauterine life was found to result in reduced birth weight, impaired skeletal development and post-natal neurotoxic effects. In this study, the effect of pre-natal exposure to different doses of lead on the development of craniofacial skeleton in rat fetuses was investigated. Vitamin E was tested as a concomitant treatment, aiming to improve the fetotoxic effects of lead. Positively pregnant female rats were randomly divided into four groups; groups I and II (L250 and L500), exposed to lead acetate in doses of 250 and 500 mg/l respectively, group III (L500 + E), exposed to lead acetate (500 mg/l) wit concomitant vitamin E and group IV (Control) which was given sodium acetate only. All the treatments started from the first day of gestation till the 20th day, where all rats were sacrificed and the fetuses were recovered. Fetuses were processed to alizarin red staining for ossified components. Twenty-seven bones of the craniofacial skeleton were studied in each fetus where the ossification was scored as being complete, delayed or absent. In all studied fetuses from all groups, changes were found only in eight bones while the remaining craniofacial bones were normally ossified. In affected bones there was a significant decrease in the number of completely ossified bones; associated with a significant increase of both partially ossified and absent bones in L(250) and L(500) treated groups when compared to the control group. These differences were more significant in the L(500) treated group. Giving vitamin E improved the percentage of completely ossified craniofacial bones and decreased the percentage of both partially ossified and absent bones. The most affected bone was presphenoid, then to a lesser extent supraoccipital, squamosal, parietal, interparietal and frontal bone respectively. In conclusion, lead exposure to rats during pregnancy led to varying degrees of fetal growth retardation as well as delayed ossification of some craniofacial bones which were dose dependent and the concomitant supplementation with vitamin E greatly improved the deleterious effect of lead.

Msx1 and Dlx5 act independently in development of craniofacial skeleton, but converge on the regulation of Bmp signaling in palate formation

Msx and Dlx homeoproteins control the morphogenesis and organization of craniofacial skeletal structures, specifically those derived from the pharyngeal arches. In vitro Msx and Dlx proteins have opposing transcriptional properties and form heterodimeric complexes via their homeodomain with reciprocal functional repression. In this report we examine the skeletal phenotype of Msx1; Dlx5 double knock-out (DKO) mice in relationship with their expression territories during craniofacial development. Co-expression of Dlx5 and Msx1 is only observed in embryonic tissues in which these genes have independent functions, and thus direct protein interactions are unlikely to control morphogenesis of the cranium. The DKO craniofacial phenotypes indicate a complex interplay between these genes, acting independently (mandible and middle ear), synergistically (deposition of bone tissue) or converging on the same morphogenetic process (palate growth and closure). In the latter case, the absence of Dlx5 rescues in part the Msx1-dependent defects in palate growth and elevation. At the basis of this effect, our data implicate the Bmp (Bmp7, Bmp4)/Bmp antagonist (Follistatin) signal: in the Dlx5−/− palate changes in the expression level of Bmp7 and Follistatin counteract the reduced Bmp4 expression. These results highlight the importance of precise spatial and temporal regulation of the Bmp/Bmp antagonist system during palate closure.

Postnatal Craniofacial Skeleton Development following a Pushback Operation of Patients with Cleft Palate

A longitudinal growth study of the craniofacial skeleton in 52 (19 males, 33 females) Danish individuals with cleft palates was performed. Thirty (13 males, 17 females) had clefts of the soft palate only or clefts extending into the posterior third of the hard palate. Twenty-two (6 males, 16 females) had more extensive clefts including up to two-thirds of the hard palate. The cleft was closed with a pushback operation at 22 months of age. Orthodontic treatment was included in the early mixed dentition. Lateral cephalometries were obtained at 5, 8, 12, 16, and 21 years of age. Twenty-four variables were digitized and analyzed. The results indicated that patients with more extensive clefts demonstrated significantly smaller anterior cranial base length (N-S), total cranial base length (N-Ba), maxillary dentoalveolar base length (A-PMP), mandibular length (Cd-Pgn), upper anterior and posterior facial heights (N-ANS and P-PMP), and total facial height (N-Gn). Patients with the more extensive clefts reached maximum growth spurt later than patients with less extensive clefts in all dimensions except the A-PMP and the lower and total facial heights.

Postnatal Craniofacial Skeleton Development Following a Pushback Operation of Patients with Cleft Palate

A longitudinal growth study of the craniofacial skeleton in 52 (19 males, 33 females) Danish individuals with cleft palates was performed. Thirty (13 males, 17 females) had clefts of the soft palate only or clefts extending into the posterior third of the hard palate. Twenty-two (6 males, 16 females) had more extensive clefts including up to two-thirds of the hard palate. The cleft was closed with a pushback operation at 22 months of age. Orthodontic treatment was included in the early mixed dentition. Lateral cephalometries were obtained at 5, 8, 12, 16, and 21 years of age. Twenty-four variables were digitized and analyzed. The results indicated that patients with more extensive clefts demonstrated significantly smaller anterior cranial base length (N-S), total cranial base length (N-Ba), maxillary dentoalveolar base length (A-PMP), mandibular length (Cd-Pgn), upper anterior and posterior facial heights (N-ANS and P-PMP), and total facial height (N-Gn). Patients with the more extensive clefts reached maximum growth spurt later than patients with less extensive clefts in all dimensions except the A-PMP and the lower and total facial heights.