NCS-1 protein regulates TRPA1 channel through the PI3K pathway in breast cancer and neuronal cells.

The physical and functional interaction between transient receptor potential channel ankyrin 1 (TRPA1) and neuronal calcium sensor 1 (NCS-1) was assessed. NCS-1 is a calcium (Ca2+) sensor found in many tissues, primarily neurons, and TRPA1 is a Ca2+ channel involved not only in thermal and pain sensation but also in conditions such as cancer and chemotherapy-induced peripheral neuropathy, in which NCS-1 is also a regulatory component.We explored the interactions between these two proteins by employing western blot, qRT-PCR, co-immunoprecipitation, Ca2+ transient monitoring with Fura-2 spectrophotometry, and electrophysiology assays in breast cancer cells (MDA-MB-231) with different levels of NCS-1 expression and neuroblastoma cells (SH-SY5Y).Our findings showed that the expression of TRPA1 was directly correlated with NCS-1 levels at both the protein and mRNA levels. Additionally, we found a physical and functional association between these two proteins. Physically, the NCS-1 and TRPA1 co-immunoprecipitate. Functionally, NCS-1 enhanced TRPA1-dependent Ca2+ influx, current density, open probability, and conductance, where the functional effects depended on PI3K. Conclusion: NCS-1 appears to act not only as a Ca2+ sensor but also modulates TRPA1 protein expression and channel function in a direct fashion through the PI3K pathway. These results contribute to understanding how Ca2+ homeostasis is regulated and provides a mechanism underlying conditions where Ca2+ dynamics are compromised, including breast cancer. With a cellular pathway identified, targeted treatments can be developed for breast cancer and neuropathy, among other related diseases.

Schizophrenia-relevant behaviours of female mice overexpressing neuregulin 1 type III.

Elevated levels of the type III (III) isoforms of neuregulin 1 (NRG1) have been observed in the brains of schizophrenia patients that carry NRG1 HapICE risk alleles, which is thought to contribute to the aetiology of the disease. We generated transgenic mice with forebrain driven Nrg1 III overexpression (Nrg1 III tg) and previously found that male heterozygous Nrg1 type III tg mice exhibit several schizophrenia-relevant behaviours including social and cognitive deficits as well as impaired sensorimotor gating. A number of mouse models for other Nrg1 isoform types exhibit sex-specific phenotypes yet sex-specific effects of Nrg1 III overexpression had not been evaluated. Thus, in this study we tested female Nrg1 III transgenic mice using a comprehensive behavioural phenotyping battery relevant to positive, negative and cognitive symptoms of schizophrenia. Firstly, forebrain Nrg1 III mRNA overexpression was confirmed in female transgenic mice using by qPCR. In the open field test, female Nrg1 III mice exhibited a blunted response to an acute challenge with the N-methyl-d-aspartate (NMDA) receptor antagonist MK-801. Female Nrg1 III tg mice also exhibited moderately impaired short-term memory. Other behavioural domains including sensory abilities, motor functions, baseline locomotion, anxiety, sociability, social recognition memory, fear conditioning and prepulse inhibition were unperturbed in Nrg1 III tg females. Together these results illustrate that overexpressing forebrain Nrg1 III in female mice modifies the locomotive response to NMDA receptor antagonism without causing severe alterations to a number of other schizophrenia-related behavioural domains. The data suggest that behavioural effects of Nrg1 III overexpression may be sex-dependent.

Overexpression of Neuregulin 1 Type III Confers Hippocampal mRNA Alterations and Schizophrenia-Like Behaviors in Mice.

Neuregulin 1 (NRG1) is a schizophrenia candidate gene whose protein product is involved in neuronal migration, survival, and synaptic plasticity via production of specific isoforms. Importantly, NRG1 type III (NRG1 III) mRNA is increased in humans inheriting a schizophrenia risk haplotype for the NRG1 gene (HapICE), and NRG1 protein levels can be elevated in schizophrenia. The nature by which NRG1 type III overexpression results in schizophrenia-like behavior and brain pathology remains unclear, therefore we constructed a transgenic mouse with Nrg1 III overexpression in forebrain neurons (CamKII kinase+). Here, we demonstrate construct validity for this mouse model, as juvenile and adult Nrg1 III transgenic mice exhibit an overexpression of Nrg1 III mRNA and Nrg1 protein in multiple brain regions. Furthermore, Nrg1 III transgenic mice have face validity as they exhibit schizophrenia-relevant behavioral phenotypes including deficits in social preference, impaired fear-associated memory, and reduced prepulse inhibition. Additionally, microarray assay of hippocampal mRNA uncovered transcriptional alterations downstream of Nrg1 III overexpression, including changes in serotonin receptor 2C and angiotensin-converting enzyme. Transgenic mice did not exhibit other schizophrenia-relevant behaviors including hyperactivity, social withdrawal, or an increased vulnerability to the effects of MK-801 malate. Our results indicate that this novel Nrg1 III mouse is valid for modeling potential pathological mechanisms of some schizophrenia-like behaviors, for determining what other neurobiological changes may be downstream of elevated NRG1 III levels and for preclinically testing therapeutic strategies that may be specifically efficacious in patients with the NRG1 (HapICE) risk genotype.

Relationship between somatostatin and death receptor expression in the orbital frontal cortex in schizophrenia: a postmortem brain mRNA study.

BACKGROUND: Recently, we provided evidence showing reductions in GAD67 and Dlx mRNAs in the orbital frontal cortex (OFC) in schizophrenia. It is unknown whether these reductions relate mainly to somatostatin (SST) or parvalbumin (PV) mRNA expression changes, and/or whether these reductions are related to decreased SST mRNA+ interneuron density. AIMS: To determine whether inhibitory interneuron deficits in the OFC from people with schizophrenia are greatest for SST or PV mRNAs, and whether any such deficits relate to mRNAs encoding cell death signalling molecules. METHODS: Inhibitory interneuron mRNAs (SST; PV: in situ hybridization, quantitative PCR (qPCR)) and death signaling mRNAs [FAS receptor (FASR); TNFSF13: qPCR] were measured in control and schizophrenia subjects (38/38). SST mRNA+ interneuron-like cells were quantified in layer II in the gyrus rectus. Gray matter SST and PV mRNAs were correlated with interstitial white matter neuron (IWMN) density (GAD65/67; NeuN) and death signaling mRNAs. RESULTS: SST mRNA was reduced in OFC layers I-VI in schizophrenia (both in situ and qPCR), with greatest deficit in layer II (67%). Layer II SST mRNA+ neuron density was reduced in schizophrenia (~29%). PV mRNA was reduced in layers III (18%) and IV (31%) with no significant diagnostic difference in PV mRNA measured by qPCR. FASR mRNA was increased in schizophrenia (34%). SST, but not PV, expression correlated negatively with FASR and TNFSF13 expressions and with IWMN density. CONCLUSIONS: Our study demonstrates that SST interneurons are predominantly linked to the inhibitory interneuron pathology in the OFC in schizophrenia and that increased death receptor signaling mRNAs relate to prominent laminar deficits in SST mRNA in the OFC in schizophrenia. We suggest that SST interneurons may be more vulnerable to increased death receptor signaling than PV interneurons.