Biology subjects

Chow, H.-M.

Publications and source records attributed to Chow, H.-M..

4 recordsLinked to original sources

bioRxiv2024

Functional and multi-omic aging rejuvenation with GLP-1R agonism

Identifying readily implementable methods that can effectively counteract aging is urgently needed for tackling age-related degenerative disorders. Here, we conducted functional assessments and deep molecular phenotyping in the aging mouse to demonstrate that glucagon-like peptide-1 receptor agonist (GLP-1RA) treatment attenuates body-wide age-related changes. Apart from improvements in physical and cognitive performance, the age-counteracting effects are prominently evident at multiple omic levels. These span the transcriptomes and DNA methylomes of various tissues, organs and circulating white blood cells, as well as the plasma metabolome. Importantly, the beneficial effects are specific to aged mice, not young adults, and are achieved with a low dosage of GLP-1RA which has a negligible impact on food consumption and body weight. The molecular rejuvenation effects exhibit organ-specific characteristics, which are generally heavily dependent on hypothalamic GLP-1R. We benchmarked the GLP-1RA age-counteracting effects against those of mTOR inhibition, a well-established anti-aging intervention, observing a strong resemblance across the two strategies. Our findings have broad implications for understanding the mechanistic basis of the clinically observed pleiotropic effects of GLP-1RAs, the design of intervention trials for age-related diseases, and the development of anti-aging-based therapeutics.

systems biology↗

bioRxiv2023

The mtDNA-derived lncMtDloop promotes mitochondrial homeostasis maintenance and implications in AD

Maintaining mitochondrial homeostasis stands as a critical factor for cell survival and the health of organisms, as evidenced by the links between mitochondrial dysfunction and a spectrum of diseases, including Alzheimers disease (AD). Here we report that lncMtDloop, a lncRNA originating from the mtDNA D-loop, upholds mitochondrial homeostasis. LncMtDloop demonstrates an affinity for mitochondrial transcription factor A (TFAM), thereby facilitating TFAMs recruitment to mtDNA promoters and enhancing gene transcription. We further observed decreased lncMtDloop expression in the brains of human AD patients and 3xTg mice. Through the introduction of allotropic lncMtDloop with the 3UTR of MRPS12, a significant improvement in mitochondrial homeostasis and a concurrent amelioration of AD-like pathology were found, which exerts a positive influence on synaptic plasticity and behavioral deficits observed in AD mice. Our study provides mechanistic insights into lncMtDloop as a regulator of mitochondrial homeostasis, shedding light on a perspective regarding its contribution to Alzheimers pathogenesis.

molecular biology↗

bioRxiv2022

Mechanical force induces DRP1-dependent asymmetrical mitochondrial fission for quality control

Mitochondria are membrane-bound organelles that perform diverse critical biological functions. They undergo constant fission and fusion, which are important for mitochondrial inheritance, functions, and quality control. While tremendous efforts have identified many factors governing mitochondria dynamics, emerging evidence indicates the involvement of various intracellular or extracellular mechanical cues. However, how mechanical stress directly modulates mitochondrial dynamics remains largely unknown. Here utilizing an optogenetic mitochondria-specific mechanostimulator to apply pulling forces to intracellular mitochondria, we find that mechanostimulation can promote mitochondrial fission, with sustained mechanostimulation triggering fission more effectively than transient one. Asymmetrical fission can occur at different sub-mitochondrial sites after force-induced mitochondrial elongation. Such force-induced fission is dependent on DRP1 and involves the wrapping of ER tubules. Moreover, mechanical force generates mitochondrial fragments without mtDNA which recruit Parkin proteins. Our results prove the mechanosensitivity and mechanoresponsiveness of mitochondria and reveal the role of mechanical cues in directly regulating mitochondrial dynamics.

cell biology↗

bioRxiv2018

ATM is activated by ATP depletion and modulates mitochondrial function through NRF1

We have uncovered new insights into the symptoms of ataxia-telangiectasia (A-T). Neurons with high physiological activity, particularly cerebellar Purkinje cells, have large and dynamic ATP demands. Depletion of ATP generates reactive oxygen species that activate ATM (the A-T Mutated gene product). Activated in this way, but not by DNA damage, ATM phosphorylates nuclear respiratory factor-1 (NRF1). This leads to NRF1 dimerization, nuclear translocation and the upregulation of nuclear-encoded mitochondrial genes, thus enhancing the capacity of the electron transport chain (ETC) and restoring mitochondrial function. In cells with ATM deficiency, resting ATP levels are normal, but cells replenish ATP poorly following surges in energy demand and chronic ATP insufficiency endangers cell survival. This is a particular problem for energy-intensive cells such as Purkinje cells, which degenerate in A-T. Our findings thus identify ATM as a guardian of mitochondrial output as well as genomic integrity, and suggest that alternate fuel sources may ameliorate A-T disease symptoms.\n\nSummaryOxidative stress, resulting from neuronal activity and depleted ATP levels, activates ATM, which phosphorylates NRF1, causing nuclear translocation and upregulation of mitochondrial gene expression. In ATM deficiency, ATP levels recover more slowly, particularly in active neurons with high energy demands.

neuroscience↗