Go to The Journal of Clinical Investigation
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Transfers
  • Advertising
  • Job board
  • Contact
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Immunology
    • Metabolism
    • Nephrology
    • Oncology
    • Pulmonology
    • All ...
  • Videos
  • Collections
    • Resource and Technical Advances
    • Clinical Medicine
    • Reviews
    • Editorials
    • Perspectives
    • Top read articles
  • JCI This Month
    • Current issue
    • Past issues

  • Current issue
  • Past issues
  • Specialties
  • In-Press Preview
  • Concise Communication
  • Editorials
  • Viewpoint
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Transfers
  • Advertising
  • Job board
  • Contact
Minor snRNA gene delivery improves the loss of proprioceptive synapses on SMA motor neurons
Erkan Y. Osman, … , Livio Pellizzoni, Christian L. Lorson
Erkan Y. Osman, … , Livio Pellizzoni, Christian L. Lorson
Published June 9, 2020
Citation Information: JCI Insight. 2020;5(12):e130574. https://doi.org/10.1172/jci.insight.130574.
View: Text | PDF
Research Article Neuroscience

Minor snRNA gene delivery improves the loss of proprioceptive synapses on SMA motor neurons

  • Text
  • PDF
Abstract

Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder caused by reduced expression of the survival motor neuron (SMN) protein. SMN has key functions in multiple RNA pathways, including the biogenesis of small nuclear ribonucleoproteins that are essential components of both major (U2-dependent) and minor (U12-dependent) spliceosomes. Here we investigated the specific contribution of U12 splicing dysfunction to SMA pathology through selective restoration of this RNA pathway in mouse models of varying phenotypic severity. We show that virus-mediated delivery of minor snRNA genes specifically improves select U12 splicing defects induced by SMN deficiency in cultured mammalian cells, as well as in the spinal cord and dorsal root ganglia of SMA mice without increasing SMN expression. This approach resulted in a moderate amelioration of several parameters of the disease phenotype in SMA mice, including survival, weight gain, and motor function. Importantly, minor snRNA gene delivery improved aberrant splicing of the U12 intron–containing gene Stasimon and rescued the severe loss of proprioceptive sensory synapses on SMA motor neurons, which are early signatures of motor circuit dysfunction in mouse models. Taken together, these findings establish the direct contribution of U12 splicing dysfunction to synaptic deafferentation and motor circuit pathology in SMA.

Authors

Erkan Y. Osman, Meaghan Van Alstyne, Pei-Fen Yen, Francesco Lotti, Zhihua Feng, Karen K.Y. Ling, Chien-Ping Ko, Livio Pellizzoni, Christian L. Lorson

×

Figure 2

Lentivirus-mediated expression of minor snRNAs improves U12 splicing defects induced by SMN deficiency in mammalian cells.

Options: View larger image (or click on image) Download as PowerPoint
Lentivirus-mediated expression of minor snRNAs improves U12 splicing def...
(A and B) RT-PCR analysis of the levels of Smn mRNA (A) and the indicated minor snRNAs (B) in Dox-treated, Smn-deficient NIH 3T3-SmnRNAi cells that were either mock transduced or transduced with lentivirus expressing human U11, U12, and U4atac snRNAs relative to untreated NIH 3T3-SmnRNAi cells with normal Smn levels (black, control – Dox; red, mock + Dox; orange, U11/U12/U4atac + Dox). Note that primers were designed to detect both endogenous mouse snRNAs and virally delivered human snRNAs. The scatter plots show individual data points, mean, and SEM from 3 independent experiments normalized to the control group. Statistics were performed using multiple t tests with the Benjamini, Krieger, and Yekutieli correction for multiple comparisons. *P < 0.05; **P < 0.01. (C) RT-PCR analysis in the same experimental groups as in A of U12 intron retention in Tspan31 mRNA, aberrant splicing of Stasimon (Stas) mRNA, and exon skipping in Clcn7 mRNA — all of which are previously characterized SMN-dependent U12 splicing defects in NIH 3T3 cells (21). Schematics of the RNA processing events monitored in the assay are shown at the top. The scatter plots show individual data points, mean, and SEM from 3 independent experiments normalized to the control group. Statistics: 1-way ANOVA with Tukey’s post hoc test. *P < 0.05; **P < 0.01; ***P < 0.001. All other pairwise comparisons between groups are not statistically significant.

Copyright © 2022 American Society for Clinical Investigation
ISSN 2379-3708

Sign up for email alerts