| 1. |
- Kagiava, Alexia, et al.
(author)
-
Gene replacement therapy in two Golgi-retained CMT1X mutants before and after the onset of demyelinating neuropathy
- 2023
-
In: MOLECULAR THERAPY METHODS & CLINICAL DEVELOPMENT. - 2329-0501. ; 30, s. 377-393
-
Journal article (peer-reviewed)abstract
- X-linked Charcot-Marie-Tooth disease type 1 (CMT1X) is a demyelinating neuropathy resulting from loss-of-function mu-tations affecting the GJB1/connexin 32 (Cx32) gene. We previ-ously showed functional and morphological improvement in Gjb1-null mice following AAV9-mediated delivery of human Cx32 driven by the myelin protein zero (Mpz) promoter in Schwann cells. However, CMT1X mutants may interfere with virally delivered wild-type (WT) Cx32. To confirm the efficacy of this vector also in the presence of CMT1X mutants, we deliv-ered AAV9-Mpz-GJB1 by lumbar intrathecal injection in R75W/Gjb1-null and N175D/Gjb1-null transgenic lines ex-pressing Golgi-retained mutations, before and after the onset of the neuropathy. Widespread expression of virally delivered Cx32 was demonstrated in both genotypes. Re-establishment of WT Cx32 function resulted in improved muscle strength and increased sciatic nerve motor conduction velocities in all treated groups from both mutant lines when treated before as well as after the onset of the neuropathy. Furthermore, morphological analysis showed improvement of myelination and reduction of inflammation in lumbar motor roots and pe-ripheral nerves. In conclusion, this study provides proof of principle for a clinically translatable gene therapy approach to treat CMT1X before and after the onset of the neuropathy, even in the presence of endogenously expressed Golgi-retained Cx32 mutants.
|
|
| 2. |
- Lopez-Font, Inmaculada, et al.
(author)
-
Decreased circulating ErbB4 ectodomain fragments as a read-out of impaired signaling function in amyotrophic lateral sclerosis.
- 2019
-
In: Neurobiology of disease. - : Elsevier BV. - 1095-953X .- 0969-9961. ; 124:April, s. 428-438
-
Journal article (peer-reviewed)abstract
- ErbB4 is a transmembrane receptor tyrosine kinase that binds to neuregulins to activate signaling. Proteolytic cleavage of ErbB4 results in release of soluble fragments of ErbB4 into the interstitial fluid. Disruption of the neuregulin-ErbB4 pathway has been suggested to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). This study assesses whether soluble proteolytic fragments of the ErbB4 ectodomain (ecto-ErbB4) can be detected in cerebrospinal fluid (CSF) and plasma, and if the levels are altered in ALS. Immunoprecipitation combined with mass spectrometry or western blotting analyses confirmed the presence of ecto-ErbB4 in human CSF. Several anti-ErbB4-reactive bands, including a 55kDa fragment, were detected in CSF. The bands were generated in the presence of neuregulin-1 (Nrg1) and were absent in plasma from ErbB4 knockout mice. Ecto-ErbB4 levels were decreased in CSF from ALS patients (n=20) and ALS with concomitant frontotemporal dementia patients (n=10), compared to age-matched controls (n=13). A similar decrease was found for the short ecto-ErbB4 fragments in plasma of the same subjects. Likewise, the 55-kDa ecto-ErbB4 fragments were decreased in the plasma of the two transgenic mouse models of ALS (SOD1G93A and TDP-43A315T). Intracellular ErbB4 fragments were decreased in the frontal cortex from SOD1G93A mice, indicating a reduction in Nrg-dependent induction of ErbB4 proteolytic processing, and suggesting impaired signaling. Accordingly, overexpression of Nrg1 induced by an adeno-associated viral vector increased the levels of the ecto-ErbB4 fragment in the SOD1G93A mice. We conclude that the determination of circulating ecto-ErbB4 fragments could be a tool to evaluate the impairment of the ErbB4 pathway and may be a useful biomarker in ALS.
|
|
