Modeling human congenital disorders with neural crest developmental defects using patient-derived induced pluripotent stem cells

Abstract

The neural crest is said to be the fourth germ layer in addition to the ectoderm, mesoderm and endoderm because of its ability to differentiate into a variety of cells that contribute to the various tissues of the vertebrate body. Neural crest cells (NCCs) can be divided into three functional groups: cranial NCCs, cardiac NCCs and trunk NCCs. Defects related to NCCs can contribute to a broad spectrum of syndromes known as neurocristopathies. Studies on the neural crest have been carried out using animal models such as Xenopus, chicks, and mice. However, the precise control of human NCC development has not been elucidated in detail due to species differences. Using induced pluripotent stem cell (iPSC) technology, we developed an in vitro disease model of neurocristopathy by inducing the differentiation of patient-derived iPSCs into NCCs and/or neural crest derivatives. It is now possible to address complicated questions regarding the pathogenetic mechanisms of neurocristopathies by characterizing cellular biological features and transcriptomes and by transplanting patient-derived NCCs in vivo. Here, we provide some examples that elucidate the pathophysiology of neurocristopathies using disease modeling via iPSCs.

Keywords: Disease modeling; Neurocristopathy; iPS cells derived neural crest cells.

Fig. 1

Overview of NCCs differentiation along the anterior–posterior axis of the embryo. Only cranial NCCs can differentiated into bone and cartilage in addition to melanocyte, cranial neurons and glial cells and odontoblasts. Cardiac NCCs migrate into 3rd-6th pharyngeal arches and give rise to aorticopulmonary septum, smooth muscle of the aorta and pulmonary artery and valvular tissue and cardiac neurons. Vagal and Sacral NCCs consists of enteric nervous system. Trunk NCCs migrate dorsolateral and ventrolateral. The former group give rise to melanocyte and the latter give rise to chromaffin cells, known as endocrine cells in adrenal glands, and the neurons of the sympathetic nervous system.

Fig. 2

Schematic overview of genes in the 22q11.2 critical region. Schematic overview of 3 Mb in the 22q11.2 region. The gray columns A, B, C, D indicate blocks of low-copy repeats, named LCR22s. Breakpoints of the deletion mostly occur in these LCR22s. Eighty-five percent of patients with chr.22q11.2 deletion syndrome have a 3 Mb deletion, and 5% harbor a 1.5 Mb deletion. Forty-four coding genes and 9 noncoding genes are located in this region. The genes listed in blue were reported to be associated with schizophrenia. TBX1 (shown in red) is known as a cardinal gene of chr.22q11.2 deletion syndrome. Eight coding genes were reported to cause autosomal recessive syndromes. ND: neural development, NC: neural crest, PA: pharyngeal arches.

Fig. 3

Defective migration of CHARGE iPSC-NCCs. A. Features of the enrolled CHARGE patients. Both patients had typical CHARGE syndrome phenotypes. B. Representative image of control (green) and CHARGE (red) iPSC-NCCs in chick embryos at 36 h after transplantation into the dorsal side of the developing neural tube at the hindbrain level in a chick embryo at HH-stage 10. C. Venn diagram of 338 differentially expressed genes between control- and CHARGE-iPSC-NCCs and 12,159 listed genes as targets of CHD7 in the ChIP-seq datasets from the ENCODE transcription factor target database.