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Disrupted in Schizophrenia 1 (DISC1) is a scaffold protein implicated in major mental illnesses including schizophrenia, with a significant negative impact on social life. To investigate if DISC1 affects social interactions in Drosophila melanogaster, we created transgenic flies with second or third chromosome insertions of the human full-length DISC1 (hflDISC1) gene fused to a UAS promotor (UAS-hflDISC1). Initial characterization of the insertion lines showed unexpected endogenous expression of the DISC1 protein that led to various behavioral and neurochemical phenotypes. Social interaction network (SIN) analysis showed altered social dynamics and organizational structures. This was in agreement with the altered levels of the locomotor activity of individual flies monitored for 24 h. Together with a decreased ability to climb vertical surfaces, the observed phenotypes indicate altered motor functions that could be due to a change in the function of the motor neurons and/or central brain. The changes in social behavior and motor function suggest that the inserted hflDISC1 gene influences nervous system functioning that parallels symptoms of DISC1-related mental diseases in humans. Furthermore, neurochemical analyses of transgenic lines revealed increased levels of hydrogen peroxide and decreased levels of glutathione, indicating an impact of DISC1 on the dynamics of redox regulation, similar to that reported in transgenic mammals. Future studies are needed to address the localization of DISC1 expression and to address how the redox parameter changes correlate with the observed behavioral changes.

Objective: To assess nuclear distribution element-like 1 (Ndel1) enzyme activity following acute administration of sodium nitroprusside (sNP) in a rodent model of schizophrenia (SCZ) and in a cohort of chronic SCZ patients. Methods: Ndel1 activity was measured following sNP infusions in spontaneously hypertensive rats (SHR) (2.5 or 5.0 mg/kg) and in a double-blind randomized trial with 15 SCZ patients (0.5 μg/kg/min). Patients were randomized into two groups (group I: n=7; group II: n=8), with one group receiving placebo and the other sNP in phase A. In phase B, the groups switched treatments. sNP was administered as an infusion of 0.5 μg/kg/min, for 4 h, while placebo was a 5% glucose solution infused under the same conditions. The infusions were administered once weekly over 4 weeks. Psychopathology was assessed using the 18-item figure 5 (BPRS-18 – Bech’s version) and the negative subscale of the Positive and Negative Syndrome Scale. Results: Ndel1 activity was significantly reduced after sNP infusion in SHR and in patients receiving sNP (t = 7.756, degrees of freedom [df] = 97, p < 0.0001, dcohen=1.44) compared to placebo. Reduced Ndel1 activity from baseline to the end of infusion was only seen in patients after treatment with sNP. Conclusion: SCZ patients may benefit from adjunctive therapy with sNP and that the Ndel1 enzyme is a candidate biomarker of psychopathology in the disorder. Future research should look into the role of Ndel1 in SCZ and the potential effects of sNP and drugs with similar profiles of action in both animals and patients.