Tissue-specific triggers of IFNa neurotoxicity: bioinformatics prediction and experimental verification
Creators: name: Obolenskaya, Maria
name: Docenko, Valeria
name: Krupko, Olga
name: Pastukhov, Artem
name: Starosila, Daria
name: Chernych, Svetlana
name: Borisova, Tatiana
Publisher: name: F1000 Research Limited
Year: 2017

description: <i>Background. </i>The high-dose IFNA therapy is widely used for the treatment of hematologic disorders, several solid tumors, multiple sclerosis and accompanied by side effects with largely undefined mechanisms of IFNA neurotoxicity. Our previous genome-wide search in rat genome for genes containing in their promoters IFN-stimulated response elements (ISRE) revealed new putative target genes of IFNA - <i>Pick1, Grin3a </i>and<i> Gabra2, </i>that encode correspondingly the protein kinase C, alpha binding protein, regulating the intracellular trafficking of glutamate AMPA receptor, and subunits of NMDA and GABA receptors.<br><br><i>Aim. </i>The goal of the study was to evaluate <i>Pick1, Grin3a </i>and<i> Gabra2, </i>mRNAs abundance along with the abundance of classical target genes of IFNA and <i>Ifna </i>mRNA itself in several regions of mouse brain and the functional activity of presynaptic NMDA receptors after administration of IFNA.<br><br><i>Methods. </i>Recombinant human IFN alpha 2b was administered intracranial. In 24 h the total RNA from six brain regions - olfactory bulb, midbrain, hippocampus, cerebellum, pons and medulla, and cortex, and synaptosomes from combined samples of cortex and hippocampus were isolated. RNA was applied for the RT-qPCR measurement of mRNAs abundance and synaptosomes for their functional activity by estimation of glutamate release from synatposomes and synaptic vesicles in response to NMDA and glutamate treatment.<br><br><i>Results. </i>In intact brain the abundance of mRNAs significantly varies in each brain region and is represented at maximal or closest to maximal level in hippocampus. The IFNA administration mainly increases the mRNAs abundances in each brain region with the utmost up-regulation in the midbrain. The accumulation and distribution of L-[14C]glutamate between synaptosomes and the extracellular space as well as percentage of AO dye accumulated by synaptic vesicles at rest do not change after intracranial injection of IFNA while NMDA and glutamate–stimulated L-[14C]glutamate and AO release increases in experimental vs. control animals and reveals the predominant role of presynaptic NMDA receptors in mediating this effect<br><br><i>Conclusion.</i> Due to intrinsic characteristics of PICK1A, GRIN3A and GABRA2 proteins the up regulation of their genes expression may promote the decrease of synaptic strength, transmission communication, responsiveness to excitatory signals and increase the susceptibility to inhibitory ones. Up regulated expression of <i>Grin3a</i> in response to IFNA injection might increase the prevalence of GRIN3A-containing NMDA receptors in preNMDARs and all over the brain with consequent functional changes corresponding to the specific properties of these receptors. GRIN3A, a key negative modulator of synapse maturation and stabilization, might be an active neuron-specific participant in psycho-emotional and cognitive disorders during IFN therapy.