The expression of P2X7 receptor in human induced pluripotent stem cell‐derived cellular model of Alzheimer’s disease

Background We aim to elucidate the role of the purinergic receptor P2X7 in the development and progression of the Alzheimer’s disease (AD) pathology in human induced pluripotent stem cell‐derived cellular model. Our model consists of iPSC‐derived mixed neuronal and astrocytic cells, together with human iPSC‐derived microglia‐like cells. Since jointly with amyloid‐β and tau pathology, neuroinflammation presents one of the main factors in AD. Thus, having microglia in the cellular model of AD is unavoidable. Method iPSC‐derived neuronal cultures were generated using the dual SMAD inhibition protocol, while microglial cells were generated through a 3D differentiation protocol, using bone morphogenetic protein 4 (BMP4), vascular endothelial growth factor (VEGF), and stem cell factor (SCF). Further differentiation was forced by adding macrophage colony‐stimulating factor (M‐CSF) and interleukin‐3 (IL‐3). Expression of cellular markers, as well as the studied P2X7R, was verified via ELISA, immunocytochemistry, western blot and RT‐qPCR. Result Our neuronal cell cultures obtained from AD patients have been previously reported to show major pathologic signs of AD, thus, suitable for AD modelling. The acquired microglia‐like cells expressed Iba1, CX3CR1, CD11c, and TMEM119, which confirms their suitability for further use. Both neuronal and microglial cells express the investigated P2X7 receptor. Moreover, based on our preliminary results, the expression of P2X7R in neurons seems to be diminished when co‐cultivated with microglia. This might suggest a temporary modulatory mechanism, activated to supplement the function of the receptor in the absence of microglia. Conclusion Based on our results, the presented cellular system offers an excellent model that can be used for studying the molecular basis of age‐related neurodegenerative diseases such as Alzheimer’s disease. Future experiments will explore the effects of P2X7R antagonism on AD pathology in our cellular model. P2X7R seems to be actively engaged in AD pathological processes, and thus, the modulation of the receptor’s activity with antagonists might present a good therapeutic approach for AD. Therefore, this research helps to validate the correlation between animal and human studies of P2X7R; and will be extended to the evaluation of the therapeutic potential of selected P2X7R antagonists in Alzheimer’s disease.