Primary Cilium-Mediated Retinal Pigment Epithelium Maturation Is Disrupted in Ciliopathy Patient Cells

Publication date: 2 January 2018
Source:Cell Reports, Volume 22, Issue 1
Author(s): Helen Louise May-Simera, Qin Wan, Balendu Shekhar Jha, Juliet Hartford, Vladimir Khristov, Roba Dejene, Justin Chang, Sarita Patnaik, Quanlong Lu, Poulomi Banerjee, Jason Silver, Christine Insinna-Kettenhofen, Dishita Patel, Mostafa Lotfi, May Malicdan, Nathan Hotaling, Arvydas Maminishkis, Rupa Sridharan, Brian Brooks, Kiyoharu Miyagishima, Meral Gunay-Aygun, Rajarshi Pal, Christopher Westlake, Sheldon Miller, Ruchi Sharma, Kapil Bharti
Primary cilia are sensory organelles that protrude from the cell membrane. Defects in the primary cilium cause ciliopathy disorders, with retinal degeneration as a prominent phenotype. Here, we demonstrate that the retinal pigment epithelium (RPE), essential for photoreceptor development and function, requires a functional primary cilium for complete maturation and that RPE maturation defects in ciliopathies precede photoreceptor degeneration. Pharmacologically enhanced ciliogenesis in wild-type induced pluripotent stem cells (iPSC)-RPE leads to fully mature and functional cells. In contrast, ciliopathy patient-derived iPSC-RPE and iPSC-RPE with a knockdown of ciliary-trafficking protein remain immature, with defective apical processes, reduced functionality, and reduced adult-specific gene expression. Proteins of the primary cilium regulate RPE maturation by simultaneously suppressing canonical WNT and activating PKCδ pathways. A similar cilium-dependent maturation pathway exists in lung epithelium. Our results provide insights into ciliopathy-induced retinal degeneration, demonstrate a developmental role for primary cilia in epithelial maturation, and provide a method to mature iPSC epithelial cells for clinical applications.

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Teaser

May-Simera et al. show that primary cilia regulate the maturation and polarization of human iPSC-RPE, mouse RPE, and human iPSC-lung epithelium through canonical WNT suppression and PKCδ activation. RPE cells derived from ciliopathy patients exhibit defective structure and function. These results provide insights into ciliopathy-induced retinal degeneration.


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