Bradykinin promotes immune responses in differentiated embryonic neurospheres carrying APP swe and PS1 dE9 mutations

Neural stem cells (NSCs) can be cultivated from developing brains, reproducing many of the processes that occur during neural development. They can be isolated from a variety of animal models, such as transgenic mice carrying mutations in amyloid precursor protein (APP) and presenilin 1 and 2 (PSEN 1 and 2), characteristic of familial Alzheimer’s Disease (AD). Modulating the development of these cells with inflammation-related peptides, like bradykinin (BK) and its antagonist HOE-140, enables the understanding of the impact of such molecules on the genetic load of treated neurospheres. To facilitate an understanding of the wider biological processes in the context of neuroinflammation, we performed a global gene expression analysis on the transgenic neurospheres treated with BK and HOE-140. To validate the microarray data, quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) was performed on 8 important genes related to the immune response in AD. We then performed a comparative analysis of the transcriptional profiles between treatments, including gene ontology and reactome enrichment, construction and analysis of protein-protein interaction networks and, finally, comparing our data with human datasetd from AD patients. We observed that the treatments modulated the expression of genes mainly related to neuroinflammation mediated by microglia, with BK promoting an increase in the expression of genes that enrich processes, pathways, and cellular components related to immune impairment, neurodegeneration and cell cycle. B2 receptor inhibition by HOE-140 acting on reduction of AD-related anomalies caused in this system. Our results reinforce that BK is an important modulating agent and enhances the immunological changes identified in transgenic neurospheres that carry the genetic load of AD. Four condition experiment, APPswe/PS1dE9 (APP_WT) vs. WT cells, APPswe/PS1dE9 vs. APPswe/PS1dE9 treated with BK (BK_APP) and APPswe/PS1dE9 vs. APPswe/PS1dE9 treated with HOE-140 (HOE_APP). Biological replicates: 4 APP, 4 WT, 4 BK replicates, 4 HOE-140.