Latest assessment methods for mitochondrial homeostasis in cognitive diseases

Mitochondria play an essential role in neural function,such as supporting normal energy metabolism,regulating reactive oxygen species,buffering physiological calcium loads,and maintaining the balance of morphology,subcellular distribution,and overall health through mitochondrial dynamics.Given the recent technological advances in the assessment of mitochondrial structure and functions,mitochondrial dysfunction has been regarded as the early and key pathophysiological mechanism of cognitive disorders such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,mild cognitive impairment,and postoperative cognitive dysfunction.This review will focus on the recent advances in mitochondrial medicine and research methodology in the field of cognitive sciences,from the perspectives of energy metabolism,oxidative stress,calcium homeostasis,and mitochondrial dynamics(including fission-fusion,transport,and mitophagy).

Targeting whole body metabolism and mitochondrial bioenergetics in the drug development for Alzheimer’s disease

Aging is by far the most prominent risk factor for Alzheimer’s disease(AD),and both aging and AD are associated with apparent metabolic alterations.As developing effective therapeutic interventions to treat AD is clearly in urgent need,the impact of modulating whole-body and intracellular metabolism in preclinical models and in human patients,on disease pathogenesis,have been explored.There is also an increasing awareness of differential risk and potential targeting strategies related to biological sex,microbiome,and circadian regulation.As a major part of intracellular metabolism,mitochondrial bioenergetics,mitochondrial quality-control mechanisms,and mitochondria-linked inflammatory responses have been considered for AD therapeutic interventions.This review summarizes and highlights these efforts.

Microfluidic devices as model platforms of CNS injury-ischemia to study axonal regeneration by regulating mitochondrial transport and bioenergetic metabolism

Central nervous system(CNS)neurons typically fail to regenerate their axons after injury leading to neurological impairment.Axonal regeneration is a highly energy-demanding cellular program that requires local mitochondria to supply most energy within injured axons.Recent emerging lines of evidence have started to reveal that injury-triggered acute mitochondrial damage and local energy crisis contribute to the intrinsic energetic restriction that accounts for axon regeneration failure in the CNS.Characterizing and reprogramming bioenergetic signaling and mitochondrial maintenance after axon injury-ischemia is fundamental for developing therapeutic strategies that can restore local energy metabolism and thus facilitate axon regeneration.Therefore,establishing reliable and reproduc-ible neuronal model platforms is critical for assessing axonal energetic metabolism and regeneration capacity after injury-ischemia.In this focused methodology article,we discuss recent advances in applying cutting-edge microflu-idic chamber devices in combination with state-of-the-art live-neuron imaging tools to monitor axonal regeneration,mitochondrial transport,bioenergetic metabolism,and local protein synthesis in response to injury-ischemic stress in mature CNS neurons.

A new method for quantifying mitochondrial axonal transport

Axonal transport of mitochondria is critical for neuronal survival and function. Automatically quantifying and analyzing mitochondrial movement in a large quantity remain challenging. Here, we report an efficient method for imaging and quantifying axonal mitochondrial trans- port using microfluidic-chamber-cultured neurons together with a newly developed analysis package named ＂MitoQuant＂. This tool-kit consists of an automated program for tracking mitochondrial movement inside live neuronal axons and a transient-velocity analysis program for analyzing dynamic movement patterns of mitochondria. Using this method, we examined axonal mitochondrial movement both in cultured mammalian neurons and in motor neuron axons of Drosophila in vivo. In 3 different paradigms （temperature changes, drug treatment and genetic manipulation） that affect mitochondria, we have shown that this new method is highly efficient and sensitive for detecting changes in mitochondrial movement. The method significantly enhanced our ability to quantitatively analyze axonal mitochondrial movement and allowed us to detect dynamic changes in axonal mltochondrial transport that were not detected by traditional kymographic analyses.