Pharaoh, G. | Search bioRxiv

bioRxiv2023

Elamipretide Improves ADP Sensitivity in Aged Mitochondria by Increasing Uptake through the Adenine Nucleotide Translocator (ANT)

Aging muscle experiences functional decline in part mediated by impaired mitochondrial ADP sensitivity. Elamipretide (ELAM) rapidly improves physiological and mitochondrial function in aging and binds directly to the mitochondrial ADP transporter ANT. We hypothesized that ELAM improves ADP sensitivity in aging leading to rescued physiological function. We measured the response to ADP stimulation in young and old muscle mitochondria with ELAM treatment, in vivo heart and muscle function, and compared protein abundance, phosphorylation, and S-glutathionylation of ADP/ATP pathway proteins. ELAM treatment increased ADP sensitivity in old muscle mitochondria by increasing uptake of ADP through the ANT and rescued muscle force and heart systolic function. Protein abundance in the ADP/ATP transport and synthesis pathway was unchanged, but ELAM treatment decreased protein s-glutathionylation incuding of ANT. Mitochondrial ADP sensitivity is rapidly modifiable. This research supports the hypothesis that ELAM improves ANT function in aging and links mitochondrial ADP sensitivity to physiological function. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/525989v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1980dc7org.highwire.dtl.DTLVardef@1b0c22eorg.highwire.dtl.DTLVardef@19c9244org.highwire.dtl.DTLVardef@46e79b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract.C_FLOATNO ELAM Binds Directly to ANT and ATP Synthase and ELAM Treatment Improves ADP Sensitivity, Increases ATP Production, and Improves Physiological Function in Old Muscles. ADP (adenosine diphosphate), ATP (adenosine triphosphate), VDAC (voltage-dependent anion channel), ANT (Adenine nucleotide translocator), H+ (proton), ROS (reactive oxygen species), NADH (nicotinamide adenine dinucleotide), FADH2 (flavin adenine dinucleotide), O2 (oxygen), ELAM (elamipretide), -SH (free thiol), -SSG (glutathionylated protein). C_FIG

physiology↗

bioRxiv2022

Mitochondrial interactome remodeling in aging mouse skeletal muscle associated with functional decline.

Genomic, transcriptomic, and proteomic approaches have been employed to gain insight into molecular underpinnings of aging in laboratory animals and in humans. However, protein function in biological systems is under complex regulation and includes factors in addition to abundance levels, such as modifications, localization, conformation, and protein-protein interactions. We have applied new robust quantitative chemical cross-linking technologies to uncover changes muscle mitochondrial interactome contributing to functional decline in aging. Statistically significant age-related changes in protein cross-link levels relating to assembly of electron transport system complexes I and IV, activity of glutamate dehydrogenase, and coenzyme-A binding in fatty acid beta-oxidation and TCA enzymes were observed. These changes showed remarkable correlation with measured CI based respiration differences within the same young-old animal pairs, indicating these cross-link levels offer new molecular insight on commonly observed age-related phenotypic differences. Overall, these system-wide quantitative mitochondrial interactome data provide the first molecular-level insight on ETS complex and substrate utilization enzyme remodeling that occur during age-related mitochondrial dysfunction. Each observed cross-link can serve as a protein conformational or protein-protein interaction probe in future studies making this dataset a unique resource for many additional in-depth molecular studies that are needed to better understand complex molecular changes that occur with aging.

systems biology↗