Aging is associated with a decline in cognitive function, which can partly be explained by the accumulation of damage to the brain cells over time. Neurons and glia undergo morphological and ultrastructure changes during aging. Over the past several years, it has become evident that at the cellular level, various hallmarks of an aging brain are closely related to mitophagy. The importance of mitochondria quality and quantity control through mitophagy is highlighted by the contribution that defects in mitochondria–autophagy crosstalk make to aging and age-related diseases. In this review, we analyze some of the more recent findings regarding the study of brain aging and neurodegeneration in the context of mitophagy. We discuss the data on the dynamics of selective autophagy in neurons and glial cells during aging and in the course of neurodegeneration, focusing on three mechanisms of mitophagy: non-receptor-mediated mitophagy, receptor-mediated mitophagy, and transcellular mitophagy. We review the role of mitophagy in neuronal/glial homeostasis and in the molecular pathogenesis of neurodegenerative disorders, such as Parkinson’s disease, Alzheimer’s disease, and other disorders. Common mechanisms of aging and neurodegeneration that are related to different mitophagy pathways provide a number of promising targets for potential therapeutic agents.
Alzheimer’s disease is the most common age-related neurodegenerative disease. Understanding of its etiology and pathogenesis is constantly expanding. Thus, the increasing attention of researchers is directed to the study of the role of mitochondrial disorders. In addition, in recent years, the concept of Alzheimer’s disease as a stress-induced disease has begun to form more and more actively. The stress-induced damage to the neuronal system can trigger a vicious circle of pathological processes, among which mitochondrial dysfunctions have a significant place, since mitochondria represent a substantial component in the anti-stress activity of the cell. The study of mitochondrial disorders in Alzheimer’s disease is relevant for at least two reasons: first, as important pathogenetic component in this disease; second, due to vital role of mitochondria in formation of the body resistance to various conditions, including stressful ones, throughout the life. This literature review analyzes the results of a number of recent studies assessing potential significance of the mitochondrial disorders in Alzheimer’s disease. The probable mechanisms of mitochondrial disorders associated with the development of this disease are considered: bioenergetic dysfunctions, changes in mitochondrial DNA (including assessment of the significance of its haplogroup features), disorders in the dynamics of these organelles, oxidative damage to calcium channels, damage to MAM complexes (membranes associated with mitochondria; mitochondria-associated membranes), disruptions of the mitochondrial quality control system, mitochondrial permeability, etc. The issues of the “primary” or “secondary” mitochondrial damage in Alzheimer’s disease are discussed. Potentials for the development of new methods for diagnosis and therapy of mitochondrial disorders in Alzheimer’s disease are considered.
The following review considers current concepts concerning the characteristics of DRP1-related mitochondrial division in brain cells during hypoxic-ischemic pathology. The functional role of DRP1 in neurons and astroglia in cerebral ischemia conditions was analyzed. We discuss the potential for regulating DRP1 activity through the selective inhibitor of mitochondrial fission, mdivi-1. The article also presents data on DRP1 involvement in astro- and microglia-mediated intercellular mitochondrial transport. Understanding of the molecular mechanisms responsible for mitochondrial fission during hypoxic-ischemic exposure will allow us to consider DRP1 as an effective therapeutic target for treating conditions with a hypoxic component.
Hypoxia-inducible factors (HIF-1α, HIF-2α, HIF-3α) regulate cellular adaptation to oxygen deprivation, but their region-specific roles in Alzheimer’s disease (AD) and AD with cerebral amyloid angiopathy (CAA) remain unclear. Using post-mortem human brain tissue from aging, AD, and AD + CAA groups, we measured all three HIF isoforms in hippocampal subfields (CA1, CA2, CA4, dentate gyrus) and anterior cingulate cortex (ACC) layers 3 and 5. In the AD hippocampus, two distinct patterns emerged: ischemia-resistant regions (CA4, DG) maintained HIF-2α and showed relative resilience, whereas vulnerable regions (CA1, CA2) exhibited HIF-1α upregulation, HIF-3α loss, and HIF-2α dysregulation. The ACC contrasts sharply with the hippocampus by preserving coordinated HIF-1α/HIF-3α regulation during aging and AD, with layer-specific divergence (exhaustion in layer 3 vs. resilience in layer 5) emerging only upon addition of CAA. Notably, HIF-2α in ACC neurons remains stably elevated across all conditions. Taken together, our results highlight HIF-2α as a potential contributor to regional vulnerability and raise the possibility that maintaining HIF-2α levels, in addition to or instead of modulating HIF-1α, could be worthy of further investigation in the context of AD and related vascular changes.