Autoantibody responses to nodal and paranodal antigens in chronic inflammatory neuropathies
JOURNAL OF NEUROIMMUNOLOGY
Authors: Mathey, E. K.; Garg, N.; Park, S. B.; Nguyen, T.; Baker, S.; Yuki, N.; Yiannikas, C.; Lin, C. S.; Spies, J. M.; Ghaoui, R.; Barnett, M. H.; Vucic, S.; Pollard, J. D.; Kiernan, M. C.
Abstract
Autoantibodies to nodal/paranodal proteins have been reported in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). To determine the frequency of anti-paranodal antibodies in our cohort of CIDP patients and to validate the presence anti-nodal antibodies in MMN, sera were screened for IgG against human neurofascin 155, contactin-1, neurofascin 186 and gliomedin using ELISA. In CIDP patients, 7% were anti-NF155 IgG(4) positive and 7% were anti-CNTN1 IgG(4) positive. Positive results were confirmed using cell based assays and indirect immunofluorescence on teased nerve fibres. We did not detect IgG autoantibodies against these nodal/paranodal antigens in MMN patients.
Unexpected phenotypic effects of a transgene integration causing a knockout of the endogenous Contactin-5 gene in mice
TRANSGENIC RESEARCH
Authors: Smirnov, Alexander V.; Kontsevaya, Galina V.; Feofanova, Natalia A.; Anisimova, Margarita V.; Serova, Irina A.; Gerlinskaya, Lyudmila A.; Battulin, Nariman R.; Moshkin, Mikhail P.; Serov, Oleg L.
Abstract
Contactins (Cntn1-6) are a family of neuronal membrane proteins expressed in the brain. They are required for establishing cell-to-cell contacts between neurons and for the growth and maturation of the axons. In humans, structural genomic variations in the Contactin genes are implicated in neurodevelopmental disorders. In addition, population genetic studies associate Contactins loci with obesity and hypertension. Cntn5 knockout mice were first described in 2003, but showed no gross physiological or behavioral abnormalities (just minor auditory defects). We report a novel Cntn5 knockout mouse line generated by a random transgene integration as an outcome of pronuclear microinjection. Investigation of the transgene integration site revealed that the 6Kbp transgene construct coding for the human granulocyte-macrophage colony-stimulating factor (hGMCSF) replaced 170 Kbp of the Cntn5 gene, including four exons. Reverse transcription PCR analysis of the Cntn5 transcripts in the wild-type and transgenic mouse lines showed that splicing of the transgene leads to a set of chimeric hGMCSF-Cntn5 transcript variants, none of which encode functional Cntn5 protein due to introduction of stop codons. Although Cntn5 knockout animals displayed no abnormalities in behavior, we noted that they were leaner, with less body mass and fat percentage than wild-type animals. Their cardiovascular parameters (heart rate, blood pressure and blood flow speed) were elevated compared to controls. These findings link Cntn5 deficiency to obesity and hypertension.