Human embryonic stem cells carrying an unbalanced translocation demonstrate impaired differentiation into trophoblasts: an in vitro model of human implantation failure
MOLECULAR HUMAN REPRODUCTION
Authors: Shpiz, A.; Kalma, Y.; Frumkin, T.; Telias, M.; Carmon, A.; Amit, A.; Ben-Yosef, D.
Abstract
Carriers of the balanced translocation t(11;22), the most common reciprocal translocation in humans, are at high risk of creating gametes with unbalanced translocation, leading to repeated miscarriages. Current research models for studying translocated embryos and the biological basis for their implantation failure are limited. The aim of this study was to elucidate whether human embryonic stem cells (hESCs) carrying the unbalanced chromosomal translocation t(11;22) can provide an explanation for repeated miscarriages of unbalanced translocated embryos. Fluorescent in situ hybridization and karyotype analysis were performed to analyze the t(11;22) in embryos during PGD and in the derived hESC line. The hESC line was characterized by RT-PCR and FACS analysis for pluripotent markers. Directed differentiation to trophoblasts was carried out by bone morphogenetic protein 4 (BMP4). Trophoblast development was analyzed by measuring beta-hCG secretion, by beta-hCG immunostaining and by gene expression of trophoblastic markers. We derived the first hESC line carrying unbalanced t(11;22), which showed the typical morphological and molecular characteristics of a hESC line. Control hESCs differentiated into trophoblasts secreted increasing levels of beta-hCG and concomitantly expressed the trophoblast genes, CDX2, TP63, KRT7, ERVW1, CGA, GCM1, KLF4 and PPARG. In contrast, differentiated translocated hESCs displayed reduced and delayed secretion of beta-hCG concomitant with impaired expression of the trophoblastic genes. The reduced activation of trophoblastic genes may be responsible for the impaired trophoblastic differentiation in t(11;22)-hESCs, associated with implantation failure in unbalanced t(11;22) embryos. Our t(11;22) hESCs are presented as a valuable human model for studying the mechanisms underlying implantation failure.
ADULT syndrome due to an R243W mutation in TP63
INTERNATIONAL JOURNAL OF DERMATOLOGY
Authors: Berk, David R.; Armstrong, Nicole L.; Shinawi, Marwan; Whelan, Alison J.
Abstract
Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome is a rare, autosomal dominant form of ectodermal dysplasia due to TP63 mutations. ADULT syndrome is much less common than the more classical forms of TP63-associated ectodermal dysplasias, such as ectrodactylyectodermal dysplasiacleft lip/palate (EEC) syndrome and ankyloblepharonectodermal defectscleft lip/palate syndrome. ADULT syndrome is characterized by ectrodactyly, syndactyly, and excessive freckling, in addition to more typical ectodermal defects, including hypodontia, lacrimal duct anomalies, hypotrichosis, and onychodysplasia. Unlike some of the other TP63-associated ectodermal dysplasias, ADULT syndrome lacks clefting and ankyloblepharon. Here, we report a three-generation family with ADULT syndrome due to an R243W mutation in TP63, a mutation that has previously been described in one patient with ADULT syndrome and eight unrelated patients with EEC syndrome.