Microglia have always been thought as the central nervous system security guard. Their functions as sensor, housekeeper and cleaner are undoubtedly essential for the system’s homeostasis. Being regulated by an almost uncountable number of genes, which act like checkpoints, microglia behavior should remain constant and healthy. However, such checkpoints may become bypassed by external stimuli, hijacking and diverting microglia to a pro-inflammatory state and, ultimately, promoting the development of Alzheimer’s disease. Universidad de Sevilla. Grado en Farmacia