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Kv7.2 subunits encoded by the KCNQ2 gene provide a major contribution to the M-current (IKM), a voltage-gated K+ current crucially involved in the regulation of neuronal excitability. Heterozygous missense variants in Kv7.2 are responsible for epileptic diseases characterized by highly heterogeneous genetic transmission and clinical severity, ranging from autosomal-dominant Benign Familial Neonatal Seizures (BFNS) to sporadic cases of severe epileptic and developmental encephalopathy (DEE). Here, we describe a patient with neonatal onset DEE, carrying a previously undescribed heterozygous KCNQ2 c.418G &gt, C, p.Glu140Gln (E140Q) variant. Patch-clamp recordings in CHO cells expressing the E140Q mutation reveal dramatic loss of function (LoF) effects. Multistate structural modelling suggested that the E140Q substitution impeded an intrasubunit electrostatic interaction occurring between the E140 side chain in S2 and the arginine at position 210 in S4 (R210), this interaction is critically involved in stabilizing the activated configuration of the voltage-sensing domain (VSD) of Kv7.2. Functional results from coupled charge reversal or disulfide trapping experiments supported such a hypothesis. Finally, retigabine restored mutation-induced functional changes, reinforcing the rationale for the clinical use of Kv7 activators as personalized therapy for DEE-affected patients carrying Kv7.2 LoF mutations.

Kv7.2-Kv7.5 channels mediate the M-current (IKM), a K+-selective current regulating neuronal excitability and representing an attractive target for pharmacological therapy against hyperexcitability diseases such as pain. Kv7 channels interact functionally with transient receptor potential vanilloid 1 (TRPV1) channels activated by endogenous and/or exogenous pain-inducing substances, such as bradykinin (BK) or capsaicin (CAP), respectively, however, whether Kv7 channels of specific molecular composition provide a dominant contribution in BK- or CAP-evoked responses is yet unknown. To this aim, Kv7 transcripts expression and function were assessed in F11 immortalized sensorial neurons, a cellular model widely used to assess nociceptive molecular mechanisms. In these cells, the effects of the pan-Kv7 activator retigabine were investigated, as well as the effects of ICA-27243 and (S)-1, two Kv7 activators acting preferentially on Kv7.2/Kv7.3 and Kv7.4/Kv7.5 channels, respectively, on BK- and CAP-induced changes in intracellular Ca2+ concentrations ([Ca2+]i). The results obtained revealed the expression of transcripts of all Kv7 genes, leading to an IKM-like current. Moreover, all tested Kv7 openers inhibited BK- and CAP-induced responses by a similar extent (~60%), at least for BK-induced Ca2+ responses, the potency of retigabine (IC50~1 &micro, M) was higher than that of ICA-27243 (IC50~5 &micro, M) and (S)-1 (IC50~7 &micro, M). Altogether, these results suggest that IKM activation effectively counteracts the cellular processes triggered by TRPV1-mediated pain-inducing stimuli, and highlight a possible critical contribution of Kv7.4 subunits.

The paired-type homeodomain transcription factor Uncx is involved in multiple processes of embryogenesis in vertebrates. Reasoning that zebrafish genes uncx4.1 and uncx are orthologs of mouse Uncx, we studied their genomic environment and developmental expression. Evolutionary analyses indicate the zebrafish uncx genes as being paralogs deriving from teleost-specific whole-genome duplication. Whole-mount in situ mRNA hybridization of uncx transcripts in zebrafish embryos reveals novel expression domains, confirms those previously known, and suggests sub-functionalization of paralogs. Using genetic mutants and pharmacological inhibitors, we investigate the role of signaling pathways on the expression of zebrafish uncx genes in developing somites. In identifying putative functional role(s) of zebrafish uncx genes, we hypothesized that they encode transcription factors that coordinate growth and innervation of somitic muscles., Highlights • The Uncx4.1 and Uncx genes derive from the teleost-specific whole-genome duplication. • Uncx genes are expressed during embryogenesis in unique and overlapping domains. • Uncx gene expression during somite differentiation is regulated by FGF signaling. • Synteny and expression profiles correlate Uncx genes with axon guidance.

Genetic testing of drug response represents an important goal for targeted therapy. In particular, 5-fluorouracil (5-FU) is the backbone of several chemotherapic protocols for treatment of solid tumors. Unfortunately, in some patients, 5-FU is toxic and causes gastrointestinal and hematologic lesions leading to the suspension of therapy. Some adverse drug responses can be predicted by pharmacogenomics. Recently, several polymorphic traits of different genes involved with 5-FU biotransformation have been reported. Many methods have been used for qualitative and quantitative assessment of the mutational status of these genes, without a precise cost-effectiveness analysis. This article reviews recent findings on the seven germline polymorphic traits of four genes involved in the biotransformation of the 5-FU. In particular, we analyze the most common platforms used to identify the specific genetic alterations and their relative costs. Genotyping can be performed either by custom service laboratories or academic reference laboratories by using either the commercial kits (when available) or “in house” tests. By random selection of 20 certified laboratories out of a total of 71, we estimate that the cost of the analysis/single trait is on average €120.00 as custom genotyping service. “In house” validated tests by PCR-based platforms cost approximately €20.00 per single polimorphism. On the basis of this information, the lab manager can evaluate the advantage and limitations, in terms of costs and applicability, of the most appropriate methods for diagnostics of 5-FU pharmacogenomics tests.