Immunomodulatory role of mesenchymal stem cells in Alzheimer's disease

Alzheimer's disease (AD) is one of the most common causes of dementia and is characterized by gradual loss in memory, language, and cognitive function. The hallmarks of AD include extracellular amyloid deposition, intracellular neuronal fiber entanglement, and neuronal loss. Despite strenuous efforts toward improvement of AD, there remains a lack of effective treatment and current pharmaceutical therapies only alleviate the symptoms for a short period of time. Interestingly, some progress has been achieved in treatment of AD based on mesenchymal stem cell (MSC) transplantation in recent years. MSC transplantation, as a rising therapy, is used as an intervention in AD, because of the enormous potential of MSCs, including differentiation potency, immunoregulatory function, and no immunological rejection. Although numerous strategies have focused on the use of MSCs to replace apoptotic or degenerating neurons, recent studies have implied that MSC-immunoregulation, which modulates the activity state of microglia or astrocytes and mediates neuroinflammation via several transcription factors (NFs) signaling pathways, may act as a major mechanism for the therapeutic efficacy of MSC and be responsible for some of the satisfactory results. In this review, we will focus on the role of MSC-immunoregulation in MSC-based therapy for AD.