Bardet-Biedl syndrome proteins regulate intracellular signaling and neuronal function in patient-specific iPSC-derived neurons
Liheng Wang, … , Claudia A. Doege, Rudolph L. Leibel
Liheng Wang, … , Claudia A. Doege, Rudolph L. Leibel
Published February 25, 2021
Citation Information: J Clin Invest. 2021;131(8):e146287. https://doi.org/10.1172/JCI146287.
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Research Article

Bardet-Biedl syndrome proteins regulate intracellular signaling and neuronal function in patient-specific iPSC-derived neurons

Abstract

Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder caused by mutations in genes encoding components of the primary cilium and is characterized by hyperphagic obesity. To investigate the molecular basis of obesity in human BBS, we developed a cellular model of BBS using induced pluripotent stem cell–derived (iPSC-derived) hypothalamic arcuate-like neurons. BBS mutations BBS1M390R and BBS10C91fsX95 did not affect neuronal differentiation efficiency but caused morphological defects, including impaired neurite outgrowth and longer primary cilia. Single-cell RNA sequencing of BBS1M390R hypothalamic neurons identified several downregulated pathways, including insulin and cAMP signaling and axon guidance. Additional studies demonstrated that BBS1M390R and BBS10C91fsX95 mutations impaired insulin signaling in both human fibroblasts and iPSC-derived neurons. Overexpression of intact BBS10 fully restored insulin signaling by restoring insulin receptor tyrosine phosphorylation in BBS10C91fsX95 neurons. Moreover, mutations in BBS1 and BBS10 impaired leptin-mediated p-STAT3 activation in iPSC-derived hypothalamic neurons. Correction of the BBS mutation by CRISPR rescued leptin signaling. POMC expression and neuropeptide production were decreased in BBS1M390R and BBS10C91fsX95 iPSC–derived hypothalamic neurons. In the aggregate, these data provide insights into the anatomic and functional mechanisms by which components of the BBSome in CNS primary cilia mediate effects on energy homeostasis.

Authors

Liheng Wang, Yang Liu, George Stratigopoulos, Sunil Panigrahi, Lina Sui, Yiying Zhang, Charles A. Leduc, Hannah J. Glover, Maria Caterina De Rosa, Lisa C. Burnett, Damian J. Williams, Linshan Shang, Robin Goland, Stephen H. Tsang, Sharon Wardlaw, Dieter Egli, Deyou Zheng, Claudia A. Doege, Rudolph L. Leibel

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Figure 6

BBS1M390R mutation reduces POMC expression in both mouse hypothalamus and human iPSC–derived hypothalamic neurons.

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BBS1M390R mutation reduces POMC expression in both mouse hypothalamus a...
(A) Body weight curve of male WT and BBS1M390R-knockin (KI) mice (n = 9, 10). (B) Intraperitoneal glucose tolerance test (IPGTT) of 10-week-old male mice on regular chow diet (n = 9, 10). (C and D) Body weight (C) and IPGTT (D) of 12-week-old male mice fed breeder chow ad libitum (n = 6, 7). (E) The glucose area under the curve (AUC) in WT and KI mice as shown in D. ***P < 0.001. (F) Body weight of 24-week-old WT and KI mice on regular chow diet (n = 9, 8). (G) IPGTT of 24-week-old WT and KI mice on regular chow diet (n = 9, 8). (H) qPCR analysis of Pomc and Npy expression in hypothalamus of WT and KI mice (24-week-old males) after 16-hour fasting followed by 4-hour refeeding (n = 5, 5). *P < 0.05, **P < 0.01 by 2-tailed Student’s t test (A–H). (I) qPCR analysis of POMC expression in day 35 iPSC-derived hypothalamic neurons (n = 3). **P < 0.01, ****P < 0.0001 by 1-way ANOVA followed by Tukey’s multiple-comparison test. (J and K) Amount of neuropeptide produced in neuronal lysates (J) and in cultured medium (16-hour culture, K) from control (n = 3), BBS1B (n = 3), BBS10A (n = 3), and c-BBS1B (n = 1) iPSC–derived hypothalamic neurons. POMC, αMSH, and βEP concentrations were measured with ELISA and radioimmunoassay and normalized to total protein.