bims-tofagi 2023-12-03 papers

on Mitophagy

Issue of 2023‒12‒03
eight papers selected by
Michele Frison, University of Cambridge and Aitor Martínez Zarate, Euskal Herriko Unibertsitatea

Mitophagy in human health, ageing and disease.
Mitochondrial quality control in health and cardiovascular diseases.
Metabolic control of mitophagy.
Restoring the infected powerhouse: Mitochondrial quality control in sepsis.
Basal activity of PINK1 and PRKN in cell models and rodent brain.
BNIP3 as a new tool to promote healthy brain aging.
CARM1 drives mitophagy and autophagy flux during fasting-induced skeletal muscle atrophy.
Mitophagy induction improves salivary gland stem/progenitor cell function by reducing senescence after irradiation.

Nat Metab. 2023 Nov 30.

Mitophagy in human health, ageing and disease.

Anna Picca, Julie Faitg, Johan Auwerx, Luigi Ferrucci, Davide D'Amico.

Maintaining optimal mitochondrial function is a feature of health. Mitophagy removes and recycles damaged mitochondria and regulates the biogenesis of new, fully functional ones preserving healthy mitochondrial functions and activities. Preclinical and clinical studies have shown that impaired mitophagy negatively affects cellular health and contributes to age-related chronic diseases. Strategies to boost mitophagy have been successfully tested in model organisms, and, recently, some have been translated into clinics. In this Review, we describe the basic mechanisms of mitophagy and how mitophagy can be assessed in human blood, the immune system and tissues, including muscle, brain and liver. We outline mitophagy's role in specific diseases and describe mitophagy-activating approaches successfully tested in humans, including exercise and nutritional and pharmacological interventions. We describe how mitophagy is connected to other features of ageing through general mechanisms such as inflammation and oxidative stress and forecast how strengthening research on mitophagy and mitophagy interventions may strongly support human health.

DOI: https://doi.org/10.1038/s42255-023-00930-8
Front Cell Dev Biol. 2023 ;11 1290046

Mitochondrial quality control in health and cardiovascular diseases.

Asli E Atici, Timothy R Crother, Magali Noval Rivas.

  Cardiovascular diseases (CVDs) are one of the primary causes of mortality worldwide. An optimal mitochondrial function is central to supplying tissues with high energy demand, such as the cardiovascular system. In addition to producing ATP as a power source, mitochondria are also heavily involved in adaptation to environmental stress and fine-tuning tissue functions. Mitochondrial quality control (MQC) through fission, fusion, mitophagy, and biogenesis ensures the clearance of dysfunctional mitochondria and preserves mitochondrial homeostasis in cardiovascular tissues. Furthermore, mitochondria generate reactive oxygen species (ROS), which trigger the production of pro-inflammatory cytokines and regulate cell survival. Mitochondrial dysfunction has been implicated in multiple CVDs, including ischemia-reperfusion (I/R), atherosclerosis, heart failure, cardiac hypertrophy, hypertension, diabetic and genetic cardiomyopathies, and Kawasaki Disease (KD). Thus, MQC is pivotal in promoting cardiovascular health. Here, we outline the mechanisms of MQC and discuss the current literature on mitochondrial adaptation in CVDs.

Keywords:  ROS; cardiovascular disease; mitobiogenesis; mitochondria; mitochondrial dynamics; mitophagy

DOI:  https://doi.org/10.3389/fcell.2023.1290046
Eur J Clin Invest. 2023 Dec 01. e14138

Metabolic control of mitophagy.

Andreas Zimmermann, Frank Madeo, Abhinav Diwan, Junichi Sadoshima, Simon Sedej, Guido Kroemer, Mahmoud Abdellatif.

  Mitochondrial dysfunction is a major hallmark of ageing and related chronic disorders. Controlled removal of damaged mitochondria by the autophagic machinery, a process known as mitophagy, is vital for mitochondrial homeostasis and cell survival. The central role of mitochondria in cellular metabolism places mitochondrial removal at the interface of key metabolic pathways affecting the biosynthesis or catabolism of acetyl-coenzyme A, nicotinamide adenine dinucleotide, polyamines, as well as fatty acids and amino acids. Molecular switches that integrate the metabolic status of the cell, like AMP-dependent protein kinase, protein kinase A, mechanistic target of rapamycin and sirtuins, have also emerged as important regulators of mitophagy. In this review, we discuss how metabolic regulation intersects with mitophagy. We place special emphasis on the metabolic regulatory circuits that may be therapeutically targeted to delay ageing and mitochondria-associated chronic diseases. Moreover, we identify outstanding knowledge gaps, such as the ill-defined distinction between basal and damage-induced mitophagy, which must be resolved to boost progress in this area.

Keywords:  AMPK; NAD; acetyl-CoA; ageing; ageing-related disease; metabolism; mitophagy; spermidine

DOI:  https://doi.org/10.1111/eci.14138
Redox Biol. 2023 Nov 23. pii: S2213-2317(23)00369-5. [Epub ahead of print]68 102968

Restoring the infected powerhouse: Mitochondrial quality control in sepsis.

F M Lira Chavez, L P Gartzke, F E van Beuningen, S E Wink, R H Henning, G Krenning, H R Bouma.

  Sepsis is a dysregulated host response to an infection, characterized by organ failure. The pathophysiology is complex and incompletely understood, but mitochondria appear to play a key role in the cascade of events that culminate in multiple organ failure and potentially death. In shaping immune responses, mitochondria fulfil dual roles: they not only supply energy and metabolic intermediates crucial for immune cell activation and function but also influence inflammatory and cell death pathways. Importantly, mitochondrial dysfunction has a dual impact, compromising both immune system efficiency and the metabolic stability of end organs. Dysfunctional mitochondria contribute to the development of a hyperinflammatory state and loss of cellular homeostasis, resulting in poor clinical outcomes. Already in early sepsis, signs of mitochondrial dysfunction are apparent and consequently, strategies to optimize mitochondrial function in sepsis should not only prevent the occurrence of mitochondrial dysfunction, but also cover the repair of the sustained mitochondrial damage. Here, we discuss mitochondrial quality control (mtQC) in the pathogenesis of sepsis and exemplify how mtQC could serve as therapeutic target to overcome mitochondrial dysfunction. Hence, replacing or repairing dysfunctional mitochondria may contribute to the recovery of organ function in sepsis. Mitochondrial biogenesis is a process that results in the formation of new mitochondria and is critical for maintaining a pool of healthy mitochondria. However, exacerbated biogenesis during early sepsis can result in accumulation of structurally aberrant mitochondria that fail to restore bioenergetics, produce excess reactive oxygen species (ROS) and exacerbate the disease course. Conversely, enhancing mitophagy can protect against organ damage by limiting the release of mitochondrial-derived damage-associated molecules (DAMPs). Furthermore, promoting mitophagy may facilitate the growth of healthy mitochondria by blocking the replication of damaged mitochondria and allow for post sepsis organ recovery through enabling mitophagy-coupled biogenesis. The remaining healthy mitochondria may provide an undamaged scaffold to reproduce functional mitochondria. However, the kinetics of mtQC in sepsis, specifically mitophagy, and the optimal timing for intervention remain poorly understood. This review emphasizes the importance of integrating mitophagy induction with mtQC mechanisms to prevent undesired effects associated with solely the induction of mitochondrial biogenesis.

Keywords:  Mitochondrial biogenesis; Mitochondrial dynamics; Mitochondrial quality control; Mitophagy; Sepsis

DOI:  https://doi.org/10.1016/j.redox.2023.102968
Autophagy. 2023 Dec 02. 1-12

Basal activity of PINK1 and PRKN in cell models and rodent brain.

Jens O Watzlawik, Fabienne C Fiesel, Gabriella Fiorino, Bernardo A Bustillos, Zahra Baninameh, Briana N Markham, Xu Hou, Caleb S Hayes, Jenny M Bredenberg, Nicholas W Kurchaba, Dominika Fričová, Joanna Siuda, Zbigniew K Wszolek, Sachiko Noda, Shigeto Sato, Nobutaka Hattori, Asheeta A Prasad, Deniz Kirik, Howard S Fox, Kelly L Stauch, Matthew S Goldberg, Wolfdieter Springer.

  The ubiquitin kinase-ligase pair PINK1-PRKN recognizes and transiently labels damaged mitochondria with ubiquitin phosphorylated at Ser65 (p-S65-Ub) to mediate their selective degradation (mitophagy). Complete loss of PINK1 or PRKN function unequivocally leads to early-onset Parkinson disease, but it is debated whether impairments in mitophagy contribute to disease later in life. While the pathway has been extensively studied in cell culture upon acute and massive mitochondrial stress, basal levels of activation under endogenous conditions and especially in vivo in the brain remain undetermined. Using rodent samples, patient-derived cells, and isogenic neurons, we here identified age-dependent, brain region-, and cell type-specific effects and determined expression levels and extent of basal and maximal activation of PINK1 and PRKN. Our work highlights the importance of defining critical risk and therapeutically relevant levels of PINK1-PRKN signaling which will further improve diagnosis and prognosis and will lead to better stratification of patients for future clinical trials.

Keywords:  Mitophagy; PINK1; PRKN; Parkinson disease; parkin; ubiquitin

DOI:  https://doi.org/10.1080/15548627.2023.2286414
Aging Cell. 2023 Nov 29. e14042

BNIP3 as a new tool to promote healthy brain aging.

Kit Neikirk, Andrea G Marshall, Monica M Santisteban, Antentor Hinton.

  The article "Neuronal induction of BNIP3-mediated mitophagy slows systemic aging in Drosophila" reveals BCL2-interacting protein 3 as a therapeutic target to counteract brain aging and prolong overall organismal health with age. In this spotlight, we consider the roles of BNIP3, a mitochondrial outer membrane protein, in the adult nervous system, including its induction of mitophagy and prevention of dysfunctional mitochondria in the aged brain. Implications for other tissue types to reduce the burden of aging are further considered.

Keywords:  BNIP3; age-related pathology; aging; mitochondria; neuronal

DOI:  https://doi.org/10.1111/acel.14042
Autophagy. 2023 Nov 29.

CARM1 drives mitophagy and autophagy flux during fasting-induced skeletal muscle atrophy.

Derek W Stouth, Tiffany L vanLieshout, Andrew I Mikhail, Sean Y Ng, Rozhin Raziee, Brittany A Edgett, Goutham Vasam, Erin K Webb, Kevin S Gilotra, Matthew Markou, Hannah C Pineda, Brianna G Bettencourt-Mora, Haleema Noor, Zachary Moll, Megan E Bittner, Brendon J Gurd, Keir J Menzies, Vladimir Ljubicic.

  CARM1 (coactivator associated arginine methyltransferase 1) has recently emerged as a powerful regulator of skeletal muscle biology. However, the molecular mechanisms by which the methyltransferase remodels muscle remain to be fully understood. In this study, carm1 skeletal muscle-specific knockout (mKO) mice exhibited lower muscle mass with dysregulated macroautophagic/autophagic and atrophic signaling, including depressed AMP-activated protein kinase (AMPK) site-specific phosphorylation of ULK1 (unc-51 like autophagy activating kinase 1; Ser555) and FOXO3 (forkhead box O3; Ser588), as well as MTOR (mechanistic target of rapamycin kinase)-induced inhibition of ULK1 (Ser757), along with AKT/protein kinase B site-specific suppression of FOXO1 (Ser256) and FOXO3 (Ser253). In addition to lower mitophagy and autophagy flux in skeletal muscle, carm1 mKO led to increased mitochondrial PRKN/parkin accumulation, which suggests that CARM1 is required for basal mitochondrial turnover and autophagic clearance. carm1 deletion also elicited PPARGC1A (PPARG coactivator 1 alpha) activity and a slower, more oxidative muscle phenotype. As such, these carm1 mKO-evoked adaptations disrupted mitophagy and autophagy induction during food deprivation and collectively served to mitigate fasting-induced muscle atrophy. Furthermore, at the threshold of muscle atrophy during food deprivation experiments in humans, skeletal muscle CARM1 activity decreased similarly to our observations in mice, and was accompanied by site-specific activation of ULK1 (Ser757), highlighting the translational impact of the methyltransferase in human skeletal muscle. Taken together, our results indicate that CARM1 governs mitophagic, autophagic, and atrophic processes fundamental to the maintenance and remodeling of muscle mass. Targeting the enzyme may provide new therapeutic approaches for mitigating skeletal muscle atrophy.

Keywords:  Atrophy; autophagy; coactivator-associated arginine methyltransferase 1; fasting; mitophagy; skeletal muscle

DOI:  https://doi.org/10.1080/15548627.2023.2288528
Radiother Oncol. 2023 Nov 23. pii: S0167-8140(23)09335-0. [Epub ahead of print] 110028

Mitophagy induction improves salivary gland stem/progenitor cell function by reducing senescence after irradiation.

Davide Cinat, Anna Lena De Souza, Abel Soto-Gamez, Anne L Jellema-de Bruin, Rob P Coppes, Lara Barazzuol.

  BACKGROUND AND PURPOSE: Patients undergoing radiotherapy for head and neck cancer often experience a decline in their quality of life due to the co-irradiation of salivary glands. Radiation-induced cellular senescence is a key factor contributing to salivary gland dysfunction. Interestingly, mitochondrial dysfunction and cellular senescence have been reported to be strongly interconnected and thus implicated in several aging-related diseases. This study aims to investigate the role of mitochondrial dysfunction in senescence induction in salivary gland stem/progenitor cells after irradiation.MATERIALS AND METHODS: A dose of 7 Gy photons was used to irradiate mouse salivary gland organoids. Senescent markers and mitochondrial function were assessed using rt-qPCR, western blot analysis, SA-β-Gal staining and flow cytometry analysis. Mitochondrial dynamics-related proteins were detected by western blot analysis while Mdivi-1 and MFI8 were used to modulate the mitochondrial fission process. To induce mitophagy, organoids were treated with Urolithin A and PMI and subsequently stem/progenitor cell self-renewal capacity was assessed as organoid forming efficiency.
RESULTS: Irradiation led to increased senescence and accumulation of dysfunctional mitochondria. This was accompanied by a strong downregulation of mitochondrial fission-related proteins and mitophagy-related genes. After irradiation, treatment with the mitophagy inducer Urolithin A attenuated the senescent phenotype and improved organoid growth and stem/progenitor cell self-renewal capacity.
CONCLUSION: This study shows the important interplay between senescence and mitochondrial dysfunction after irradiation. Importantly, activation of mitophagy improved salivary gland stem/progenitor cell function thereby providing a novel therapeutic strategy to restore the regenerative capacity of salivary glands following irradiation.

Keywords:  irradiation; mitochondria; salivary glands; senescence; stem cells

DOI:  https://doi.org/10.1016/j.radonc.2023.110028