ABSTRACT
Mutations in the SZT2 gene have been associated with developmental and epileptic encephalopathy-18, a rare severe autosomal recessive neurologic disorder, characterized by psychomotor impairment/intellectual disability, dysmorphic facial features and early onset of refractory seizures. Here we report the generation of the first induced pluripotent stem cell (iPSC) lines from a patient with treatment-resistant epilepsy, carrying compound heterozygous mutations in SZT2 (Mut1: c.498G>T and Mut2: c.6553C>T), and his healthy heterozygous parents. Peripheral blood mononuclear cells were reprogrammed by a non-integrating Sendai virus-based reprogramming system. The generated human iPSC lines exhibited expression of the main pluripotency markers, the potential to differentiate into all three germ layers and presented a normal karyotype. These lines represent a valuable resource to study neurodevelopmental alterations, and to obtain mature, pathology-relevant neuronal populations as an in vitro model to perform functional assays and test the patient's responsiveness to novel antiepileptic treatments.
Subject(s)
Epilepsy, Generalized , Induced Pluripotent Stem Cells , Humans , Induced Pluripotent Stem Cells/metabolism , Leukocytes, Mononuclear , Mutation , Heterozygote , Nerve Tissue Proteins/metabolismABSTRACT
Seizure threshold 2 (SZT2) is a component of the KICSTOR complex which, under catabolic conditions, functions as a negative regulator in the amino acid-sensing branch of mTORC1. Mutations in this gene cause a severe neurodevelopmental and epileptic encephalopathy whose main symptoms include epilepsy, intellectual disability, and macrocephaly. As SZT2 remains one of the least characterized regulators of mTORC1, in this work we performed a systematic interactome analysis under catabolic and anabolic conditions. Besides numerous mTORC1 and AMPK signaling components, we identified clusters of proteins related to autophagy, ciliogenesis regulation, neurogenesis, and neurodegenerative processes. Moreover, analysis of SZT2 ablated cells revealed increased mTORC1 signaling activation that could be reversed by Rapamycin or Torin treatments. Strikingly, SZT2 KO cells also exhibited higher levels of autophagic components, independent of the physiological conditions tested. These results are consistent with our interactome data, in which we detected an enriched pool of selective autophagy receptors/regulators. Moreover, preliminary analyses indicated that SZT2 alters ciliogenesis. Overall, the data presented form the basis to comprehensively investigate the physiological functions of SZT2 that could explain major molecular events in the pathophysiology of developmental and epileptic encephalopathy in patients with SZT2 mutations.
Subject(s)
Multiprotein Complexes/metabolism , Nerve Tissue Proteins/metabolism , Protein Interaction Maps , Amino Acids/deficiency , Animals , Blood Proteins/pharmacology , Cilia/drug effects , Cilia/metabolism , Dogs , HEK293 Cells , Humans , Madin Darby Canine Kidney Cells , Mechanistic Target of Rapamycin Complex 1/antagonists & inhibitors , Mechanistic Target of Rapamycin Complex 1/metabolism , Organogenesis/drug effects , Principal Component Analysis , Protein Interaction Maps/drug effects , Sirolimus/pharmacologyABSTRACT
To date, more than 200 monogenic, often devastating, skin diseases have been described. Because of unmet medical needs, development of long-lasting and curative therapies has been consistently attempted, with the aim of correcting the underlying molecular defect. In this review, we will specifically address the few combined cell and gene therapy strategies that made it to the clinics. Based on these studies, what can be envisioned for the future is a patient-oriented strategy, built on the specific features of the individual in need. Most likely, a combination of different strategies, approaches, and advanced therapies will be required to reach the finish line at the end of the long and winding road hampering the achievement of definitive treatments for genodermatoses.
