Antioxidant Activity of Fluoxetine and Vortioxetine in a Non-Transgenic Animal Model of Alzheimer’s Disease

Depression is a risk factor for the development of Alzheimer’s disease (AD). A neurobiological and clinical continuum exists between AD and depression, with neuroinflammation and oxidative stress being involved in both diseases. Second-generation antidepressants, in particular selective serotonin reuptake inhibitors (SSRIs), are currently investigated as neuroprotective drugs in AD. By employing a non-transgenic AD model, obtained by intracerebroventricular (i.c.v.) injection of amyloid-β (Aβ) oligomers in 2-month-old C57BL/6 mice, we recently demonstrated that the SSRI fluoxetine (FLX) and the multimodal antidepressant vortioxetine (VTX) reversed the depressive-like phenotype and memory deficits induced by Aβ oligomers rescuing the levels of transforming growth factor-β1 (TGF-β1). Aim of our study was to test FLX and VTX for their ability to prevent oxidative stress in the hippocampus of Aβ-injected mice, a brain area strongly affected in both depression and AD. The long-term intraperitoneal (i.p.) administration of FLX (10 mg/kg) or VTX (5 and 10 mg/kg) for 24 days, starting 7 days before Aβ injection, was able to prevent the over-expression of inducible nitric oxide synthase (iNOS) and NADPH oxidase 2 (Nox2) induced by Aβ oligomers. Antidepressant pre-treatment was also able to rescue the mRNA expression of glutathione peroxidase 1 (Gpx1) antioxidant enzyme. FLX and VTX also prevented Aβ-induced neurodegeneration in mixed neuronal cultures treated with Aβ oligomers. Our data represent the first evidence that the long-term treatment with the antidepressants FLX or VTX can prevent the oxidative stress phenomena related to the cognitive deficits and depressive-like phenotype observed in a non-transgenic animal model of AD.

Development of the First Transgenic Animal Model for IRF4-Induced Lymphoid Malignancy

Introduction The transcription factor IRF4, a member of Interferon Regulatory Factor (IRF) family, is a critical regulator for the production of functional B and T lymphocytes. The dysregulation of IRF4 expression has been frequently implicated in various mature B- and T-lymphoid malignancies such as multiple myeloma and peripheral T-cell lymphomas in which IRF4 acts as an oncogene. However, in vivo model systems to investigate the oncogenic property of IRF4 has not been established. One of common downstream targets of IRF4 across different cancers is the oncogene, MYC, which promotes cell proliferation. Other downstream targets or collaborating factors of IRF4 in these malignancies have not been fully elucidated. Here, we established the first transgenic animal model for IRF4-induced lymphoma, which displays multiple spectrum of tumors providing an in vivo platform to study IRF4 oncogenicity. Methods and Results To identify the specific lineages and stages of the hematopoietic cells that can be transformed by IRF4, we utilized the zebrafish lck promoter, which is active both in T- and B-lymphocytes. We overexpressed human IRF4 gene in zebrafish under this promoter along with a fluorescent marker gene. We confirmed successful expression of both IRF4 and marker genes in the lymphocyte population. Strikingly, multiple F0 transgenic zebrafish showed an expansion of fluorescent signals arising from the thymus by 5 months, while control fish showed thymic involution after 4 months. Approximately 20% of F1 animals developed lymphoma within 5 months and progressed to leukemia by 8 months. Histopathological examination revealed massive infiltration of abnormal lymphocytes into skin, spinal cord, muscles, and liver, which resembles clinical and pathological features observed in several types of human mature T-cell neoplasms. Interestingly, the tumor onset and progression were significantly accelerated when crossed with p53e7/e7-mutant fish, which possesses transactivation-dead p53 variant. This reveals the synergy between IRF4 expression and p53 loss of function, which have also been observed in several types of human lymphomas. Notably, analysis of gene expression profiles using the single-cell RNA-sequencing platform revealed a simultaneous development of both B- and T-cell tumors, which consist of multiple clones at the early stage of tumorigenesis. T-cell-derived tumors became dominant at the late stage of tumorigenesis. Importantly, the expressions of mycb, the zebrafish orthologue of human MYC, as well as of other lymphoid transcription factors were highly upregulated in those tumors in parallel with IRF4 expression. Conclusion Our study demonstrated that IRF4 serves as a driver oncogene in the development of T- and B-cell malignancies. IRF4 accelerates the tumor progression by taking advantage of the impaired function of p53, as demonstrated by massive infiltration into distal organs recapitulating human lymphomas. Taken together, our zebrafish IRF4 model provides a very powerful platform to investigate the plausible mechanisms and pathways through which IRF4 exert its oncogenic property in lymphomagenesis. Disclosures Iida: Teijin Pharma: Research Funding; Astellas: Research Funding; Gilead: Research Funding; Sanofi: Research Funding; MSD: Research Funding; Abbvie: Research Funding; Kyowa Kirin: Research Funding; Chugai: Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Daichi Sankyo: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

PO-054 Research on Animal models of Alzheimer’s Disease

Objective This paper analysis amount of literature about domestic and abroad with establishing the animal model of AD as the basics point of the research, and explore the construction of animal models of AD and the theoretical basis of the study. The purpose of the paper was to better probe AD Pathogenesis and etiology, and how to take appropriate intervention methods to lay the foundation. Methods Results Following the analysis, we found that the animal models of AD were mainly modeled by transgenic animal model, modeled by AD histopathological features, cholinergic nerve injury, aging, multifactorial complex, and ischemia and hypoxia. Each modeling method was based on the corresponding theoretical research carried out on the basis of the current research, however, the exact pathogenesis of AD was not clear, so the scholars in a variety of hypotheses on the premise Under the experimental animal model, naturally with a certain degree of one-sidedness. Transgenic animal model is expensive, disease resistance was poor, it was difficult to carry out a large amount of experimental study; cholinergic neuron damage in AD experimental animals for cholinergic function impairment and cognitive function of the ideal study. Conclusions The modeling method of AD had many advantages and disadvantages, and the compound animal model of AD was more complex than single factor modeling. Thus, no matter which way AD animal model, it was difficult to replicate all the typical pathological changes in AD, suggesting that the pathogenesis of AD and its pathological changes in the complexity and multi-factor.