Down-regulation of the brain-specific cell-adhesion molecule contactin-3 in tuberous sclerosis complex during the early postnatal period

Abstract

Background The genetic disorder tuberous sclerosis complex (TSC) is frequently accompanied by the development of neuropsychiatric disorders, including autism spectrum disorder and intellectual disability, with varying degrees of impairment. These co-morbidities in TSC have been linked to the structural brain abnormalities, such as cortical tubers, and recurrent epileptic seizures (in 70–80% cases). Previous transcriptomic analysis of cortical tubers revealed dysregulation of genes involved in cell adhesion in the brain, which may be associated with the neurodevelopmental deficits in TSC. In this study we aimed to investigate the expression of one of these genes – cell-adhesion molecule contactin-3. Methods Reverse transcription quantitative polymerase chain reaction for the contactin-3 gene (CNTN3) was performed in resected cortical tubers from TSC patients with drug-resistant epilepsy (n = 35, age range: 1–48 years) and compared to autopsy-derived cortical control tissue (n = 27, age range: 0–44 years), as well as by western blot analysis of contactin-3 (n = 7 vs n = 7, age range: 0–3 years for both TSC and controls) and immunohistochemistry (n = 5 TSC vs n = 4 controls). The expression of contactin-3 was further analyzed in fetal and postnatal control tissue by western blotting and in-situ hybridization, as well as in the SH-SY5Y neuroblastoma cell line differentiation model in vitro. Results CNTN3 gene expression was lower in cortical tubers from patients across a wide range of ages (fold change = − 0.5, p < 0.001) as compared to controls. Contactin-3 protein expression was lower in the age range of 0–3 years old (fold change = − 3.8, p < 0.001) as compared to the age-matched controls. In control brain tissue, contactin-3 gene and protein expression could be detected during fetal development, peaked around birth and during infancy and declined in the adult brain. CNTN3 expression was induced in the differentiated SH-SY5Y neuroblastoma cells in vitro (fold change = 6.2, p < 0.01). Conclusions Our data show a lower expression of contactin-3 in cortical tubers of TSC patients during early postnatal period as compared to controls, which may affect normal brain development and might contribute to neuropsychiatric co-morbidities observed in patients with TSC.

GABAA receptor function is enhanced by Interleukin-10 in human epileptogenic gangliogliomas and its effect is counteracted by Interleukin-1β

“…Immunohistochemistry (patients are reported in Table 1 ) was carried out as previously described 65 . The primary antibody against IL-10 receptor alpha (IL-10Rα, rabbit polyclonal, Genetex, Irvine, CA, USA, 1:150) was incubated at room temperature for 1 h for single labelling.…”

“…All library preparation, sequencing and bioinformatic analyses including differential expression analysis were carried out as previously described 65 (patients are reported in Supplementary Information). Differential expression analysis compared 21 TSC patients and 15 age-matched control cortices; 37 GG patients and 15 age-matched controls cortices.…”

Epileptogenesis in tuberous sclerosis complex-related developmental and epileptic encephalopathy

“… 91 Notably, lower expression of the cell-adhesion molecule contactin-3 in TSC brain during the early postnatal period is a hypothetical pathophysiological mechanism. 109 …”

Specific Features of Focal Cortical Dysplasia in Tuberous Sclerosis Complex

“…Contactin-3, an immunoglobulin-like NCAM, is downregulated in cortical tubers at the RNA and protein levels, especially during the early postnatal period, which is critical for brain development. The lack of contactin-3 may be involved in the development of neurodevelopmental and behavioral disorders in TSC [84]. Alterations in glutamatergic and GABAergic synaptic transmission are critically involved in hyperexcitability and epileptogenesis as well as in the buffering of the extracellular potassium levels [31].…”