Patient-derived iPSC-cerebral organoid modeling of the 17q11.2 microdeletion syndrome establishes CRLF3 as a critical regulator of neurogenesis

Neurodevelopmental disorders are often caused by chromosomal microdeletions encompassing numerous contiguous genes. One such microdeletion on chromosome 17q11.2, involving the NF1 gene and flanking regions ( NF1 total gene deletion; NF1 -TGD), occurs in a subset of Neurofibromatosis type 1 (NF1) patients with severe developmental delays and intellectual disability. Using patient-derived human induced pluripotent stem cell (hiPSC)-cerebral organoids (hCOs), we identified both neural stem cell (NSC) proliferation and neuronal maturation abnormalities in NF1 -TGD hCOs. While increased NSC proliferation resulted from decreased NF1 /RAS regulation, the neuronal defects (delayed neuronal differentiation, increased immature neuron apoptosis, and impaired dendrite maturation) were caused by reduced cytokine receptor-like factor 3 ( CRLF3 ) expression. Furthermore, we demonstrated a higher autistic trait burden in NF1 patients harboring a deleterious germline mutation in the CRLF3 gene (c.1166T>C, p.Leu389Pro). Collectively, these findings identify a new causative gene within the NF1 -TGD locus responsible for hCO neuronal abnormalities and autism in children with NF1.

神经发育障碍（Neurodevelopmental disorders）多由涵盖多个邻接基因的染色体微缺失引发。17号染色体q11.2区域存在一类此类微缺失，涉及NF1基因及其侧翼区域（NF1全基因缺失；NF1-TGD），该变异见于一小部分伴有严重发育迟缓与智力障碍的1型神经纤维瘤病（Neurofibromatosis type 1, NF1）患者。本研究借助患者来源的人类诱导多能干细胞（human induced pluripotent stem cell, hiPSC）源性脑类器官（cerebral organoids, hCOs），发现NF1-TGD hCOs中存在神经干细胞（neural stem cell, NSC）增殖与神经元成熟异常。其中，NSC增殖升高源于NF1/RAS调控通路的减弱，而神经元缺陷（神经元分化延迟、未成熟神经元凋亡增加及树突成熟受损）则由细胞因子受体样因子3（cytokine receptor-like factor 3, CRLF3）表达下调所导致。进一步研究显示，携带CRLF3基因有害生殖系突变（c.1166T>C，p.Leu389Pro）的NF1患者，其自闭症特征负荷更高。综上，本研究明确了NF1-TGD基因座内的新致病基因，该基因可引发NF1患儿的hCO神经元异常与自闭症表型。