Mitochondrial Calcium Signaling as a Therapeutic Target for Alzheimer’s Disease

Mitochondria absorb calcium (Ca²⁺) at the expense of the electrochemical gradient generated during respiration. The influx of Ca²⁺ into the mitochondrial matrix helps maintain metabolic function and results in increased cytosolic Ca²⁺ during intracellular Ca²⁺ signaling. Mitochondrial Ca²⁺ homeosta-sis is tightly regulated by proteins located in the inner and outer mitochondrial membranes and by the cross-talk with endoplasmic reticulum Ca²⁺ signals. Increasing evidence indicates that mitochondrial Ca²⁺ overload is a pathological phenotype associated with Alzheimer’s Disease (AD). As intracellular Ca²⁺ dysregulation can be observed before the appearance of typical pathological hallmarks of AD, it is believed that mitochondrial Ca²⁺ overload may also play an important role in AD etiology. The high mi-tochondrial Ca²⁺ uptake can easily compromise neuronal functions and exacerbate AD progression by impairing mitochondrial respiration, increasing reactive oxygen species formation and inducing apopto-sis. Additionally, mitochondrial Ca²⁺ overload can damage mitochondrial recycling via mitophagy. This review will discuss the molecular players involved in mitochondrial Ca²⁺ dysregulation and the pharma-cotherapies that target this dysregulation. As most of the current AD therapeutics are based on amyloi-dopathy, tauopathy, and the cholinergic hypothesis, they achieve only symptomatic relief. Thus, deter-mining how to reestablish mitochondrial Ca²⁺ homeostasis may aid in the development of novel AD therapeutic interventions.