Siyu Chen

All Publications

• Primary cilia formation requires the Leigh syndrome-associated mitochondrial protein NDUFAF2. The Journal of clinical investigation Lo, C. H., Liu, Z., Chen, S., Lin, F., Berneshawi, A. R., Yu, C. Q., Koo, E. B., Kowal, T. J., Ning, K., Hu, Y., Wang, W. J., Liao, Y. J., Sun, Y. 2024; 134 (13)

  Abstract

  Mitochondria-related neurodegenerative diseases have been implicated in the disruption of primary cilia function. Mutation in an intrinsic mitochondrial complex I component NDUFAF2 has been identified in Leigh syndrome, a severe inherited mitochondriopathy. Mutations in ARMC9, which encodes a basal body protein, cause Joubert syndrome, a ciliopathy with defects in the brain, kidney, and eye. Here, we report a mechanistic link between mitochondria metabolism and primary cilia signaling. We discovered that loss of NDUFAF2 caused both mitochondrial and ciliary defects in vitro and in vivo and identified NDUFAF2 as a binding partner for ARMC9. We also found that NDUFAF2 was both necessary and sufficient for cilia formation and that exogenous expression of NDUFAF2 rescued the ciliary and mitochondrial defects observed in cells from patients with known ARMC9 deficiency. NAD+ supplementation restored mitochondrial and ciliary dysfunction in ARMC9-deficient cells and zebrafish and ameliorated the ocular motility and motor deficits of a patient with ARMC9 deficiency. The present results provide a compelling mechanistic link, supported by evidence from human studies, between primary cilia and mitochondrial signaling. Importantly, our findings have significant implications for the development of therapeutic approaches targeting ciliopathies.

  View details for DOI 10.1172/JCI175560

  View details for PubMedID 38949024

• Base editing correction of OCRL in Lowe syndrome: ABE-mediated functional rescue in patient-derived fibroblasts. Human molecular genetics Chen, S., Lo, C. H., Liu, Z., Wang, Q., Ning, K., Li, T., Sun, Y. 2024

  Abstract

  Lowe syndrome, a rare X-linked multisystem disorder presenting with major abnormalities in the eyes, kidneys, and central nervous system, is caused by mutations in OCRL gene (NG_008638.1). Encoding an inositol polyphosphate 5-phosphatase, OCRL catalyzes the hydrolysis of PI(4,5)P2 into PI4P. There are no effective targeted treatments for Lowe syndrome. Here, we demonstrate a novel gene therapy for Lowe syndrome in patient fibroblasts using an adenine base editor (ABE) that can efficiently correct pathogenic point mutations. We show that ABE8e-NG-based correction of a disease-causing mutation in a Lowe patient-derived fibroblast line containing R844X mutation in OCRL gene, restores OCRL expression at mRNA and protein levels. It also restores cellular abnormalities that are hallmarks of OCRL dysfunction, including defects in ciliogenesis, microtubule anchoring, α-actinin distribution, and F-actin network. The study indicates that ABE-mediated gene therapy is a feasible treatment for Lowe syndrome, laying the foundation for therapeutic application of ABE in the currently incurable disease.

  View details for DOI 10.1093/hmg/ddae045

  View details for PubMedID 38557732