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Cite this page: Hill, M.A. (2021, August 4) Embryology Pharyngeal arches. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Pharyngeal_arches
Tbx1 and Foxi3 genetically interact in the pharyngeal pouch endoderm in a mouse model for 22q11.2 deletion syndrome
Abstract We investigated whether Tbx1, the gene for 22q11.2 deletion syndrome (22q11.2DS) and Foxi3, both required for segmentation of the pharyngeal apparatus (PA) to individual arches, genetically interact. We found that all Tbx1+/-;Foxi3+/- double heterozygous mouse embryos had thymus and parathyroid gland defects, similar to those in 22q11.2DS patients. We then examined Tbx1 and Foxi3 heterozygous, null as well as conditional Tbx1Cre and Sox172A-iCre/+ null mutant embryos. While Tbx1Cre/+;Foxi3f/f embryos had absent thymus and parathyroid glands, Foxi3-/- and Sox172A-iCre/+;Foxi3f/f endoderm conditional mutant embryos had in addition, interrupted aortic arch type B and retroesophageal origin of the right subclavian artery, which are all features of 22q11.2DS. Tbx1Cre/+;Foxi3f/f embryos had failed invagination of the third pharyngeal pouch with greatly reduced Gcm2 and Foxn1 expression, thereby explaining the absence of thymus and parathyroid glands. Immunofluorescence on tissue sections with E-cadherin and ZO-1 antibodies in wildtype mouse embryos at E8.5-E10.5, revealed that multilayers of epithelial cells form where cells are invaginating as a normal process. We noted that excessive multilayers formed in Foxi3-/-, Sox172A-iCre/+;Foxi3f/f as well as Tbx1 null mutant embryos where invagination should have occurred. Several genes expressed in the PA epithelia were downregulated in both Tbx1 and Foxi3 null mutant embryos including Notch pathway genes Jag1, Hes1, and Hey1, suggesting that they may, along with other genes, act downstream to explain the observed genetic interaction. We found Alcam and Fibronectin extracellular matrix proteins were reduced in expression in Foxi3 null but not Tbx1 null embryos, suggesting that some, but not all of the downstream mechanisms are shared. PMID: 31412026 PMCID: PMC6709926 DOI: 10.1371/journal.pgen.1008301
Foxi1 promotes late-stage pharyngeal pouch morphogenesis through ectodermal Wnt4a activation
Dev Biol. 2018 Sep 1;441(1):12-18. doi: 10.1016/j.ydbio.2018.06.011. Epub 2018 Jun 19.
Jin S1, O J2, Stellabotte F3, Choe CP4. Author information Abstract The pharyngeal pouches are a series of epithelial outgrowths of the foregut endoderm. Pharyngeal pouches segment precursors of the vertebrate face into pharyngeal arches and pattern the facial skeleton. These pouches fail to develop normally in zebrafish foxi1 mutants, yet the role Foxi1 plays in pouch development remains to be determined. Here we show that ectodermal Foxi1 acts downstream of Fgf8a during the late stage of pouch development to promote rearrangement of pouch-forming cells into bilayers. During this phase, foxi1 and wnt4a are coexpressed in the facial ectoderm and their expression is expanded in fgf8a mutants. foxi1 expression is unaffected in wnt4a mutants; conversely, ectodermal wnt4a expression is abolished in foxi1 mutants. Consistent with this, foxi1 mutant pouch and facial skeletal defects resemble those of wnt4a mutants. These findings suggest that ectodermal Foxi1 mediates late-stage pouch morphogenesis through wnt4a expression. We therefore propose that Fox1 activation of Wnt4a in the ectoderm signals the epithelial stabilization of pouch-forming cells during late-stage of pouch morphogenesis.
KEYWORDS: Epithelial morphogenesis; Fgf8; Foxi1; Pharyngeal pouches; Wnt4; Zebrafish PMID: 29932895 DOI: 10.1016/j.ydbio.2018.06.011
Branchial anomalies in children: A report of 105 surgical cases
Int J Pediatr Otorhinolaryngol. 2018 Jan;104:14-18. doi: 10.1016/j.ijporl.2017.10.035. Epub 2017 Oct 29.
Li W1, Xu H1, Zhao L1, Li X2.
BACKGROUND: Branchial anomalies (BAs) account for 20% of all congenital masses in children. We sought to review the incidence of involvement of individual anomalies, diagnostic methods, surgical treatment, and complications of BAs in children. In addition, we also classified our study and analyzed a congenital lower neck cutaneous fistula near the sternoclavicular joint that was thought to be the skin-side remnant of the fourth BAs. METHODS: We conducted a retrospective analysis of 105 children who were referred to our hospital from June 2009 to December 2016 for the treatment of BAs. RESULTS: In this series, there were 51 males and 54 females. The age at the time of operation varied from 19 days to 13 years, and the mean age was 4.5 years. A total of 33 (31.4%) cases presented with first BAs, 13 (12.4%) presented with second BAs, and 59 (56.2%) presented with third and fourth BAs, including 6 cases of congenital lower neck cutaneous fistula. Fistulectomy under general anesthesia was performed on all of them. For postoperative complications, 2 cases had temporary facial paralysis, 1 case had permanent facial paralysis, 4 cases had temporary recurrent laryngeal nerve injury. Recurrence occurred in 2 patients with first BAs after medium follow-up time of 3.6 years (6 months-8 years). CONCLUSIONS: BAs are common congenital head and neck lesions in children, and there are four distinct types (first, second, third and fourth anomalies). The incidence of third and fourth BAs in Asia maybe higher when compared with literature reports, second BAs seem rare in this population, but more research is needed to confirm this perspective. Diagnosis is not difficult with a proper knowledge of the anatomy of the BAs. The surgical procedures should be tailored depending on the various types, and complete excision of the fistula is the key to prevent recurrence. Copyright © 2017 Elsevier B.V. All rights reserved. KEYWORDS: Branchial anomalies; Children; Cutaneous fistula; Surgery
PMID: 29287855 DOI: 10.1016/j.ijporl.2017.10.035
Endothelium in the pharyngeal arches 3, 4 and 6 is derived from the second heart field
Dev Biol. 2017 Jan 15;421(2):108-117. doi: 10.1016/j.ydbio.2016.12.010. Epub 2016 Dec 9.
Wang X1, Chen D2, Chen K3, Jubran A4, Ramirez A2, Astrof S5.
Oxygenated blood from the heart is directed into the systemic circulation through the aortic arch arteries (AAAs). The AAAs arise by remodeling of three symmetrical pairs of pharyngeal arch arteries (PAAs), which connect the heart with the paired dorsal aortae at mid-gestation. Aberrant PAA formation results in defects frequently observed in patients with lethal congenital heart disease. How the PAAs form in mammals is not understood. The work presented in this manuscript shows that the second heart field (SHF) is the major source of progenitors giving rise to the endothelium of the pharyngeal arches 3 - 6, while the endothelium in the pharyngeal arches 1 and 2 is derived from a different source. During the formation of the PAAs 3 - 6, endothelial progenitors in the SHF extend cellular processes toward the pharyngeal endoderm, migrate from the SHF and assemble into a uniform vascular plexus. This plexus then undergoes remodeling, whereby plexus endothelial cells coalesce into a large PAA in each pharyngeal arch. Taken together, our studies establish a platform for investigating cellular and molecular mechanisms regulating PAA formation and alterations that lead to disease. Copyright © 2016 Elsevier Inc. All rights reserved.
PMID 27955943 PMCID: PMC5221477 [Available on 2018-01-15] DOI: 10.1016/j.ydbio.2016.12.010