bims-tofagi 2023-08-27 papers

on Mitophagy

Issue of 2023‒08‒27
25 papers selected by
Michele Frison, University of Cambridge and Aitor Martínez Zarate, Euskal Herriko Unibertsitatea

Nix interacts with WIPI2 to induce mitophagy.
PINK1 and Parkin regulate IP3R-mediated ER calcium release.
Role of Mitochondria-ER Contact Sites in Mitophagy.
The actin binding protein profilin 1 is critical for mitochondria function.
Healthy mitochondrial DNA in balanced mitochondrial dynamics: A potential marker for neuro‑aging prediction (Review).
The evolution of selective autophagy as a mechanism of oxidative stress response: The evolutionarily acquired ability of selective autophagy receptors to respond to oxidative stress is beneficial for human longevity.
Alterations of lipid-mediated mitophagy result in aging-dependent sensorimotor defects.
Relationship between ferroptosis and mitophagy in renal fibrosis: a systematic review.
Research progress of mitophagy in chronic cerebral ischemia.
Ca2+ signalling: A common language for organelles crosstalk in Parkinson's disease.
Diosgenin Targets CaMKK2 to Alleviate Type II Diabetic Nephropathy through Improving Autophagy, Mitophagy and Mitochondrial Dynamics.
Post-translational modifications and protein quality control of mitochondrial channels and transporters.
Mitochondrial Transfer Between Cell Crosstalk - An Emerging Role in Mitochondrial Quality Control.
Acid ground nano-realgar processed product inhibits breast cancer by inducing mitophagy via the p53/BNIP3/NIX pathway.
Autophagy/Mitophagy in Airway Diseases: Impact of Oxidative Stress on Epithelial Cells.
Autophagy and mitophagy-related extracellular mitochondrial dysfunction of cerebrospinal fluid cells in patients with hemorrhagic moyamoya disease.
Investigation of PRKN Mutations in Levodopa-Induced Dyskinesia in Parkinson's Disease Treatment.
[Effect of mitophagy related genes on the antioxidant properties of Saccharomyces cerevisiae].
PPARγ activation suppresses chondrocyte ferroptosis through mitophagy in osteoarthritis.
Transcriptome Highlights Cannabinol Modulation of Mitophagy in a Parkinson's Disease In Vitro Model.
Lipotoxicity-polarised macrophage-derived exosomes regulate mitochondrial fitness through Miro1-mediated mitophagy inhibition and contribute to type 2 diabetes development in mice.
Mitochondrial Dysfunction in Repeat Expansion Diseases.
The deubiquitinase Leon/USP5 interacts with Atg1/ULK1 and antagonizes autophagy.
Transcription Factor Forkhead Box P (Foxp) 1 Reduces Brain Damage During Cerebral Ischemia-Reperfusion Injury in Mice Through FUNDC1.
SIRT5 Activation and Inorganic Phosphate Binding Reduce Cancer Cell Vitality by Modulating Autophagy/Mitophagy and ROS.

EMBO J. 2023 Aug 25. e113491

Nix interacts with WIPI2 to induce mitophagy.

Eric N Bunker, François Le Guerroué, Chunxin Wang, Marie-Paule Strub, Achim Werner, Nico Tjandra, Richard J Youle.

  Nix is a membrane-anchored outer mitochondrial protein that induces mitophagy. While Nix has an LC3-interacting (LIR) motif that binds to ATG8 proteins, it also contains a minimal essential region (MER) that induces mitophagy through an unknown mechanism. We used chemically induced dimerization (CID) to probe the mechanism of Nix-mediated mitophagy and found that both the LIR and MER are required for robust mitophagy. We find that the Nix MER interacts with the autophagy effector WIPI2 and recruits WIPI2 to mitochondria. The Nix LIR motif is also required for robust mitophagy and converts a homogeneous WIPI2 distribution on the surface of the mitochondria into puncta, even in the absence of ATG8s. Together, this work reveals unanticipated mechanisms in Nix-induced mitophagy and the elusive role of the MER, while also describing an interesting example of autophagy induction that acts downstream of the canonical initiation complexes.

Keywords:  Autophagy; BNIP3; FIP200; LIR; p62

DOI:  https://doi.org/10.15252/embj.2023113491
Nat Commun. 2023 Aug 25. 14(1): 5202

PINK1 and Parkin regulate IP3R-mediated ER calcium release.

Su Jin Ham, Heesuk Yoo, Daihn Woo, Da Hyun Lee, Kyu-Sang Park, Jongkyeong Chung.

Although defects in intracellular calcium homeostasis are known to play a role in the pathogenesis of Parkinson's disease (PD), the underlying molecular mechanisms remain unclear. Here, we show that loss of PTEN-induced kinase 1 (PINK1) and Parkin leads to dysregulation of inositol 1,4,5-trisphosphate receptor (IP3R) activity, robustly increasing ER calcium release. In addition, we identify that CDGSH iron sulfur domain 1 (CISD1, also known as mitoNEET) functions downstream of Parkin to directly control IP3R. Both genetic and pharmacologic suppression of CISD1 and its Drosophila homolog CISD (also known as Dosmit) restore the increased ER calcium release in PINK1 and Parkin null mammalian cells and flies, respectively, demonstrating the evolutionarily conserved regulatory mechanism of intracellular calcium homeostasis by the PINK1-Parkin pathway. More importantly, suppression of CISD in PINK1 and Parkin null flies rescues PD-related phenotypes including defective locomotor activity and dopaminergic neuronal degeneration. Based on these data, we propose that the regulation of ER calcium release by PINK1 and Parkin through CISD1 and IP3R is a feasible target for treating PD pathogenesis.

DOI: https://doi.org/10.1038/s41467-023-40929-z
Biomolecules. 2023 Jul 31. pii: 1198. [Epub ahead of print]13(8):

Role of Mitochondria-ER Contact Sites in Mitophagy.

Alina Rühmkorf, Angelika Bettina Harbauer.

  Mitochondria are often referred to as the "powerhouse" of the cell. However, this organelle has many more functions than simply satisfying the cells' metabolic needs. Mitochondria are involved in calcium homeostasis and lipid metabolism, and they also regulate apoptotic processes. Many of these functions require contact with the ER, which is mediated by several tether proteins located on the respective organellar surfaces, enabling the formation of mitochondria-ER contact sites (MERCS). Upon damage, mitochondria produce reactive oxygen species (ROS) that can harm the surrounding cell. To circumvent toxicity and to maintain a functional pool of healthy organelles, damaged and excess mitochondria can be targeted for degradation via mitophagy, a form of selective autophagy. Defects in mitochondria-ER tethers and the accumulation of damaged mitochondria are found in several neurodegenerative diseases, including Parkinson's disease and amyotrophic lateral sclerosis, which argues that the interplay between the two organelles is vital for neuronal health. This review provides an overview of the different mechanisms of mitochondrial quality control that are implicated with the different mitochondria-ER tether proteins, and also provides a novel perspective on how MERCS are involved in mediating mitophagy upon mitochondrial damage.

Keywords:  mitochondria; mitophagy; organellar contact sites

DOI:  https://doi.org/10.3390/biom13081198
bioRxiv. 2023 Aug 16. pii: 2023.08.07.552354. [Epub ahead of print]

The actin binding protein profilin 1 is critical for mitochondria function.

Tracy-Ann Read, Bruno A Cisterna, Kristen Skruber, Samah Ahmadieh, Halli L Lindamood, Josefine A Vitriol, Yang Shi, Austin E Y T Lefebvre, Joseph B Black, Mitchell T Butler, James A Bear, Alena Cherezova, Daria V Ilatovskaya, Neil L Weintraub, Eric A Vitriol.

Profilin 1 (PFN1) is an actin binding protein that is vital for the polymerization of monomeric actin into filaments. Here we screened knockout cells for novel functions of PFN1 and discovered that mitophagy, a type of selective autophagy that removes defective or damaged mitochondria from the cell, was significantly upregulated in the absence of PFN1. Despite successful autophagosome formation and fusion with the lysosome, and activation of additional mitochondrial quality control pathways, PFN1 knockout cells still accumulate damaged, dysfunctional mitochondria. Subsequent imaging and functional assays showed that loss of PFN1 significantly affects mitochondria morphology, dynamics, and respiration. Further experiments revealed that PFN1 is located to the mitochondria matrix and is likely regulating mitochondria function from within rather than through polymerizing actin at the mitochondria surface. Finally, PFN1 mutants associated with amyotrophic lateral sclerosis (ALS) fail to rescue PFN1 knockout mitochondrial phenotypes and form aggregates within mitochondria, further perturbing them. Together, these results suggest a novel function for PFN1 in regulating mitochondria and identify a potential pathogenic mechanism of ALS-linked PFN1 variants.

DOI: https://doi.org/10.1101/2023.08.07.552354
Biomed Rep. 2023 Sep;19(3): 64

Healthy mitochondrial DNA in balanced mitochondrial dynamics: A potential marker for neuro‑aging prediction (Review).

Made Putra Semadhi, Dewi Mulyaty, Eli Halimah, Jutti Levita.

  The mitochondrial genome or mitochondrial DNA (mtDNA) is released as a response to cellular stress. In mitochondrial biogenesis, active communication between the mitochondria genome and nucleus is associated with the mtDNA profile that affects the mitochondrial quality. The present review aimed to assess the molecular mechanism and potential roles of mitochondria in neuro-aging, including the importance of evaluating the health status of mtDNA via mitochondrial dynamics. The normal condition of mitochondria, defined as mitochondrial dynamics, includes persistent changes in morphology due to fission and fusion events and autophagy-mitophagy in the mitochondrial quality control process. The calculated copy number of mtDNA in the mitochondria genome represents cellular health, which can be affected by a long-term imbalance between the production and accumulation of reactive oxygen species in the neuroendocrine system, which leads to an abnormal function of mitochondria and mtDNA damage. Mitochondria health is a new approach to discovering a potential indicator for the health status of the nervous system and several types of neurodegenerative disorders. Mitochondrial dynamics is a key contributor to predicting neuro-aging development, which affects the self-renewal and differentiation of neurons in cell metabolism. Neuro-aging is associated with uncontrolled mitochondrial dynamics, which generates age-associated diseases via various mechanisms and signaling routes that lead to the mtDNA damage that has been associated with neurodegeneration. Future studies on the strategic positioning of mtDNA health profile are needed to detect early neurodegenerative disorders.

Keywords:  cellular health; mitochondrial DNA; mitochondrial dynamics; neuro-aging

DOI:  https://doi.org/10.3892/br.2023.1646
Bioessays. 2023 Aug 21. e2300076

The evolution of selective autophagy as a mechanism of oxidative stress response: The evolutionarily acquired ability of selective autophagy receptors to respond to oxidative stress is beneficial for human longevity.

Joshua Ratliffe, Tetsushi Kataura, Elsje G Otten, Viktor I Korolchuk.

  Ageing is associated with a decline in autophagy and elevated reactive oxygen species (ROS), which can breach the capacity of antioxidant systems. Resulting oxidative stress can cause further cellular damage, including DNA breaks and protein misfolding. This poses a challenge for longevous organisms, including humans. In this review, we hypothesise that in the course of human evolution selective autophagy receptors (SARs) acquired the ability to sense and respond to localised oxidative stress. We posit that in the vicinity of protein aggregates and dysfunctional mitochondria oxidation of key cysteine residues in SARs induces their oligomerisation which initiates autophagy. The degradation of damaged cellular components thus could reduce ROS production and restore redox homeostasis. This evolutionarily acquired function of SARs may represent one of the biological adaptations that contributed to longer lifespan. Inversely, loss of this mechanism can lead to age-related diseases associated with impaired autophagy and oxidative stress.

Keywords:  ageing; aggrephagy; autophagy; mitophagy; neurodegeneration; oxidative stress; selective autophagy receptors

DOI:  https://doi.org/10.1002/bies.202300076
Aging Cell. 2023 Aug 23. e13954

Alterations of lipid-mediated mitophagy result in aging-dependent sensorimotor defects.

Natalia Oleinik, Onder Albayram, Mohamed Faisal Kassir, F Cansu Atilgan, Chase Walton, Eda Karakaya, John Kurtz, Alexander Alekseyenko, Habeeb Alsudani, Megan Sheridan, Zdzislaw M Szulc, Besim Ogretmen.

  The metabolic consequences of mitophagy alterations due to age-related stress in healthy aging brains versus neurodegeneration remain unknown. Here, we demonstrate that ceramide synthase 1 (CerS1) is transported to the outer mitochondrial membrane by the p17/PERMIT transporter that recognizes mislocalized mitochondrial ribosomes (mitoribosomes) via 39-FLRN-42 residues, inducing ceramide-mediated mitophagy. P17/PERMIT-CerS1-mediated mitophagy attenuated the argininosuccinate/fumarate/malate axis and induced d-glucose and fructose accumulation in neurons in culture and brain tissues (primarily in the cerebellum) of wild-type mice in vivo. These metabolic changes in response to sodium-selenite were nullified in the cerebellum of CerS1to/to (catalytically inactive for C18-ceramide production CerS1 mutant), PARKIN-/- or p17/PERMIT-/- mice that have dysfunctional mitophagy. Whereas sodium selenite induced mitophagy in the cerebellum and improved motor-neuron deficits in aged wild-type mice, exogenous fumarate or malate prevented mitophagy. Attenuating ceramide-mediated mitophagy enhanced damaged mitochondria accumulation and age-dependent sensorimotor abnormalities in p17/PERMIT-/- mice. Reinstituting mitophagy using a ceramide analog drug with selenium conjugate, LCL768, restored mitophagy and reduced malate/fumarate metabolism, improving sensorimotor deficits in old p17/PERMIT-/- mice. Thus, these data describe the metabolic consequences of alterations to p17/PERMIT/ceramide-mediated mitophagy associated with the loss of mitochondrial quality control in neurons and provide therapeutic options to overcome age-dependent sensorimotor deficits and related disorders like amyotrophic lateral sclerosis (ALS).

Keywords:  CerS1; Drp1; aging; ceramide; mitochondrial metabolism; mitophagy; neurodegeneration; sensorimotor defects

DOI:  https://doi.org/10.1111/acel.13954
J Drug Target. 2023 Aug 23. 1-9

Relationship between ferroptosis and mitophagy in renal fibrosis: a systematic review.

Mingyu Zhang, Ziyuan Tong, Yaqing Wang, Wenjing Fu, Yilin Meng, Jiayi Huang, Li Sun.

  Renal fibrosis, characterised by glomerulosclerosis and tubulointerstitial fibrosis, is a typical pathological alteration in the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD). However, the limited and expensive options for treating renal fibrosis place a heavy financial burden on patients and healthcare systems. Therefore, it is significant to find an effective treatment for renal fibrosis. Ferroptosis, a non-traditional form of cell death, has been found to play an important role in acute kidney injury (AKI), tumours, neurodegenerative diseases, and so on. Moreover, a growing body of research suggests that ferroptosis might be a potential target of renal fibrosis. Meanwhile, mitophagy is a type of selective autophagy that can selectively degrade damaged or dysfunctional mitochondria as a form of mitochondrial quality control, reducing the production of reactive oxygen species (ROS), the accumulation of which is the main cause of renal fibrosis. Additionally, as a receptor of mitophagy, NIX can release beclin1 to induce mitophagy, which can also bind to solute carrier family 7 member 11 (SLC7A11) to block the activity of cystine/glutamate antitransporter (system Xc-) and inhibit ferroptosis, thereby suggesting a link between mitophagy and ferroptosis. However, there have been only limited studies on the relationship among mitophagy, ferroptosis and renal fibrosis. In this paper, we review the mechanisms of mitophagy, and describe how ferroptosis and mitophagy are related to renal fibrosis in an effort to identify potential novel targets for the treatment of renal fibrosis.

Keywords:  Mitophagy; ferroptosis; mechanism; relationship; renal fibrosis

DOI:  https://doi.org/10.1080/1061186X.2023.2250574
Front Aging Neurosci. 2023 ;15 1224633

Research progress of mitophagy in chronic cerebral ischemia.

Mayue Yu, Manqing Zhang, Peijie Fu, Moxin Wu, Xiaoping Yin, Zhiying Chen.

  Chronic cerebral ischemia (CCI), a condition that can result in headaches, dizziness, cognitive decline, and stroke, is caused by a sustained decrease in cerebral blood flow. Statistics show that 70% of patients with CCI are aged > 80 years and approximately 30% are 45-50 years. The incidence of CCI tends to be lower, and treatment for CCI is urgent. Studies have confirmed that CCI can activate the corresponding mechanisms that lead to mitochondrial dysfunction, which, in turn, can induce mitophagy to maintain mitochondrial homeostasis. Simultaneously, mitochondrial dysfunction can aggravate the insufficient energy supply to cells and various diseases caused by CCI. Regulation of mitophagy has become a promising therapeutic target for the treatment of CCI. This article reviews the latest progress in the important role of mitophagy in CCI and discusses the induction pathways of mitophagy in CCI, including ATP synthesis disorder, oxidative stress injury, induction of reactive oxygen species, and Ca2+ homeostasis disorder, as well as the role of drugs in CCI by regulating mitophagy.

Keywords:  chronic cerebral ischemia; mitochondrial autophagy; oxidative stress; stroke; treatment

DOI:  https://doi.org/10.3389/fnagi.2023.1224633
Cell Calcium. 2023 Jul 27. pii: S0143-4160(23)00094-5. [Epub ahead of print]115 102783

Ca2+ signalling: A common language for organelles crosstalk in Parkinson's disease.

Caterina Peggion, Lucia Barazzuol, Elena Poggio, Tito Calì, Marisa Brini.

  Parkinson's disease (PD) is a neurodegenerative disease caused by multifactorial pathogenic mechanisms. Familial PD is linked with genetic mutations in genes whose products are either associated with mitochondrial function or endo-lysosomal pathways. Of note, mitochondria are essential to sustain high energy demanding synaptic activity of neurons and alterations in mitochondrial Ca2+ signaling have been proposed as causal events for neurodegenerative process, although the mechanisms responsible for the selective loss of specific neuronal populations in the different neurodegenerative diseases is still not clear. Here, we specifically discuss the importance of a correct mitochondrial communication with the other organelles occurring at regions where their membranes become in close contact. We discuss the nature and the role of contact sites that mitochondria establish with ER, lysosomes, and peroxisomes, and how PD related proteins participate in the regulation/dysregulation of the tethering complexes. Unravelling molecular details of mitochondria tethering could contribute to identify specific therapeutic targets and develop new strategies to counteract the progression of the disease.

Keywords:  Calcium signalling; Mitochondria; Organelles contact sites; Parkinson's disease

DOI:  https://doi.org/10.1016/j.ceca.2023.102783
Nutrients. 2023 Aug 11. pii: 3554. [Epub ahead of print]15(16):

Diosgenin Targets CaMKK2 to Alleviate Type II Diabetic Nephropathy through Improving Autophagy, Mitophagy and Mitochondrial Dynamics.

Yujie Zhong, Ruyi Jin, Ruilin Luo, Jiayu Liu, Luting Ren, Yinghan Zhang, Zhongguo Shan, Xiaoli Peng.

  Diabetic nephropathy (DN) is a worldwide health problem with increasing incidence. Diosgenin (DIO) is a natural active ingredient extracted from Chinese yams (Rhizoma dioscoreae) with potential antioxidant, anti-inflammatory, and antidiabetic effects. However, the protective effect of DIO on DN is still unclear. The present study explored the mitigating effects and underlying mechanisms of DIO on DN in vivo and in vitro. In the current study, the DN rats were induced by a high-fat diet and streptozotocin and then treated with DIO and metformin (Mef, a positive control) for 8 weeks. The high-glucose (HG)-induced HK-2 cells were treated with DIO for 24 h. The results showed that DIO decreased blood glucose, biomarkers of renal damage, and renal pathological changes with an effect comparable to that of Mef, indicating that DIO is potential active substance to relieve DN. Thus, the protective mechanism of DIO on DN was further explored. Mechanistically, DIO improved autophagy and mitophagy via the regulation of the AMPK-mTOR and PINK1-MFN2-Parkin pathways, respectively. Knockdown of CaMKK2 abolished AMPK-mTOR and PINK1-MFN2-Parkin pathways-mediated autophagy and mitophagy. Mitophagy and mitochondrial dynamics are closely linked physiological processes. DIO also improved mitochondrial dynamics through inhibiting fission-associated proteins (DRP1 and p-DRP1) and increasing fusion proteins (MFN1/2 and OPA1). The effects were abolished by CaMKK2 and PINK1 knockdown. In conclusion, DIO ameliorated DN by enhancing autophagy and mitophagy and by improving mitochondrial dynamics in a CaMKK2-dependent manner. PINK1 and MFN2 are proteins that concurrently regulated mitophagy and mitochondrial dynamics.

Keywords:  CaMKK2; autophagy; diabetic nephropathy; diosgenin; mitochondrial dynamics; mitophagy

DOI:  https://doi.org/10.3390/nu15163554
Front Cell Dev Biol. 2023 ;11 1196466

Post-translational modifications and protein quality control of mitochondrial channels and transporters.

Ashlesha Kadam, Pooja Jadiya, Dhanendra Tomar.

  Mitochondria play a critical role in energy metabolism and signal transduction, which is tightly regulated by proteins, metabolites, and ion fluxes. Metabolites and ion homeostasis are mainly mediated by channels and transporters present on mitochondrial membranes. Mitochondria comprise two distinct compartments, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM), which have differing permeabilities to ions and metabolites. The OMM is semipermeable due to the presence of non-selective molecular pores, while the IMM is highly selective and impermeable due to the presence of specialized channels and transporters which regulate ion and metabolite fluxes. These channels and transporters are modulated by various post-translational modifications (PTMs), including phosphorylation, oxidative modifications, ions, and metabolites binding, glycosylation, acetylation, and others. Additionally, the mitochondrial protein quality control (MPQC) system plays a crucial role in ensuring efficient molecular flux through the mitochondrial membranes by selectively removing mistargeted or defective proteins. Inefficient functioning of the transporters and channels in mitochondria can disrupt cellular homeostasis, leading to the onset of various pathological conditions. In this review, we provide a comprehensive overview of the current understanding of mitochondrial channels and transporters in terms of their functions, PTMs, and quality control mechanisms.

Keywords:  MCU; MPQC; MPTP; SLCs; VDAC; mitochondrial channels; mitochondrial transporters; posttranslational modifications

DOI:  https://doi.org/10.3389/fcell.2023.1196466
Ageing Res Rev. 2023 Aug 23. pii: S1568-1637(23)00197-6. [Epub ahead of print] 102038

Mitochondrial Transfer Between Cell Crosstalk - An Emerging Role in Mitochondrial Quality Control.

Yi Liu, Tinglv Fu, Guorui Li, Boyang Li, Guoqing Luo, Ning Li, Qing Geng.

  Intercellular signaling and component conduction are essential for multicellular organisms' homeostasis, and mitochondrial transcellular transport is a key example of such cellular component exchange. In physiological situations, mitochondrial transfer is linked with biological development, energy coordination, and clearance of harmful components, remarkably playing important roles in maintaining mitochondrial quality. Mitochondria are engaged in many critical biological activities, like oxidative metabolism and biomolecular synthesis, and are exclusively prone to malfunction in pathological processes. Importantly, severe mitochondrial damage will further amplify the defects in the mitochondrial quality control system, which will mobilize more active mitochondrial transfer, replenish exogenous healthy mitochondria, and remove endogenous damaged mitochondria to facilitate disease outcomes. This review explores intercellular mitochondrial transport in cells, its role in cellular mitochondrial quality control, and the linking mechanisms in cellular crosstalk. We also describe advances in therapeutic strategies for diseases that target mitochondrial transfer.

Keywords:  cell crosstalk; intercellular mitochondrial transfer; mitochondrial quality control; therapy

DOI:  https://doi.org/10.1016/j.arr.2023.102038
J Cell Mol Med. 2023 Aug 23.

Acid ground nano-realgar processed product inhibits breast cancer by inducing mitophagy via the p53/BNIP3/NIX pathway.

Jiahui Fang, Xue Zou, Ling Gong, Juan Xi, Yi Liu, Xiaoli Yang, Xiuqiao Zhang, Chun Gui.

  Breast cancer is a highly prevalent malignancy with the first morbidity and the primary reason for female cancer-related deaths worldwide. Acid ground nano-realgar processed product (NRPP) could inhibit breast cancer cell proliferation and induce autophagy in our previous research; however, the underlying mechanisms are still unclear. Therefore, this research aimed to verify whether NRPP induces breast cancer mitophagy and explore the mitophagy-mediated mechanism. Primarily, rhodamine-123 assay and transmission electron microscopy were applied to detect mitochondrial membrane potential (MMP) and ultrastructural changes in the MDA-MB-435S cells, respectively. Mito-Tracker Green/Lyso-Tracker Red staining, western blot, immunofluorescence and RT-PCR were used to explore molecular mechanisms of NRPP-induced mitophagy in vitro. MDA-MB-435S breast cancer xenograft models were established to assess the activity and mechanisms of NRPP in vivo. Our results showed that NRPP decreased MMP and increased autophagosome numbers in MDA-MB-435S cells and activated mitophagy. Furthermore, mitophagy was consolidated because mitochondria and lysosomes colocalized phenomenology were observed, and the expression of LC3II/I and COXIV was upregulated. Additionally, we found the p53/BNIP3/NIX pathway was activated. Finally, NRPP inhibited tumour growth and downregulated the levels of TNF-α, IL-1β and IL-6. Necrosis, damaged mitochondria and autophagosomes were observed in xenograft tumour cells, and proteins and mRNA levels of LC3, p53, BNIP3 and NIX were increased. Overall, NRPP inhibited MDA-MB-435S cell proliferation and tumour growth by inducing mitophagy via the p53/BNIP3/NIX pathway. Thus, NRPP is a promising candidate for breast cancer treatment.

Keywords:  MDA-MB-435S cell; acid ground nano-realgar processed product; breast cancer; mitophagy; p53/BNIP3/NIX

DOI:  https://doi.org/10.1111/jcmm.17917
Biomolecules. 2023 Aug 04. pii: 1217. [Epub ahead of print]13(8):

Autophagy/Mitophagy in Airway Diseases: Impact of Oxidative Stress on Epithelial Cells.

Giusy Daniela Albano, Angela Marina Montalbano, Rosalia Gagliardo, Mirella Profita.

  Autophagy is the key process by which the cell degrades parts of itself within the lysosomes. It maintains cell survival and homeostasis by removing molecules (particularly proteins), subcellular organelles, damaged cytoplasmic macromolecules, and by recycling the degradation products. The selective removal or degradation of mitochondria is a particular type of autophagy called mitophagy. Various forms of cellular stress (oxidative stress (OS), hypoxia, pathogen infections) affect autophagy by inducing free radicals and reactive oxygen species (ROS) formation to promote the antioxidant response. Dysfunctional mechanisms of autophagy have been found in different respiratory diseases such as chronic obstructive lung disease (COPD) and asthma, involving epithelial cells. Several existing clinically approved drugs may modulate autophagy to varying extents. However, these drugs are nonspecific and not currently utilized to manipulate autophagy in airway diseases. In this review, we provide an overview of different autophagic pathways with particular attention on the dysfunctional mechanisms of autophagy in the epithelial cells during asthma and COPD. Our aim is to further deepen and disclose the research in this direction to stimulate the develop of new and selective drugs to regulate autophagy for asthma and COPD treatment.

Keywords:  COPD; asthma; autophagy; lung disease; mitophagy; oxidative stress

DOI:  https://doi.org/10.3390/biom13081217
Sci Rep. 2023 Aug 23. 13(1): 13753

Autophagy and mitophagy-related extracellular mitochondrial dysfunction of cerebrospinal fluid cells in patients with hemorrhagic moyamoya disease.

First Korean Stroke Genetics Association Research (The FirstKSGAR) study

We aimed to investigate whether mitochondrial dysfunction in extracellular cerebrospinal fluid (CSF), which is associated with autophagy and mitophagy, might be involved in neurological outcomes in adult patients with hemorrhagic moyamoya disease (MMD) whose pathogenesis related to poor outcomes is not well-known. CSF samples were collected from 43 adult MMD patients and analyzed according to outcomes at 3 months. Fluorescence-activated cell sorter analysis (FACS) and the JC-1 red/green ratio were used to assess mitochondrial cells and intact mitochondrial membrane potential (MMP). We performed quantitative real-time polymerase chain reaction and Western blotting analyses of autophagy and mitophagy-related markers, including HIF1α, ATG5, pBECN1, BECN1, BAX, BNIP3L, DAPK1, and PINK1. Finally, FACS analysis with specific fluorescence-conjugated antibodies was performed to evaluate the potential cellular origin of CSF mitochondrial cells. Twenty-seven females (62.8%) with a mean age of 47.4 ± 9.7 years were included in the study. Among 43 patients with hemorrhagic MMD, 23 (53.5%) had poor outcomes. The difference in MMP was evident between the two groups (2.4 ± 0.2 in patients with poor outcome vs. 3.5 ± 0.4 in patients with good outcome; p = 0.02). A significantly higher expression (2-ΔCt) of HIF1α, ATG5, DAPK1 followed by BAX and BNIP3L mRNA and protein was also observed in poor-outcome patients compared to those with good outcomes. Higher percentage of vWF-positive mitochondria, suggesting endothelial cell origins, was observed in patients with good outcome compared with those with poor outcome (25.0 ± 1.4% in patients with good outcome vs. 17.5 ± 1.5% in those with poor outcome; p < 0.01). We observed the association between increased mitochondrial dysfunction concomitant with autophagy and mitophagy in CSF cells and neurological outcomes in adult patients with hemorrhagic MMD. Further prospective multicenter studies are needed to determine whether it has a diagnostic value for risk prediction.

DOI: https://doi.org/10.1038/s41598-023-40747-9
Biomedicines. 2023 Aug 09. pii: 2230. [Epub ahead of print]11(8):

Investigation of PRKN Mutations in Levodopa-Induced Dyskinesia in Parkinson's Disease Treatment.

Ana Gabrielle Bispo, Caio S Silva, Camille Sena-Dos-Santos, Dafne Dalledone Moura, Brenda Hanae Bentes Koshimoto, Bruno Lopes Santos-Lobato, Ândrea Ribeiro-Dos-Santos, Giovanna C Cavalcante.

  Mitophagy is an important process that participates in mitochondrial quality control. Dysfunctions in this process can be caused by mutations in genes like PRKN and are associated with the development and progression of Parkinson's Disease (PD). The most used drug in the treatment of PD is levodopa (LD), but it can cause adverse effects, such as dyskinesia. Currently, few studies are searching for biomarkers for an effective use of lLD for this disease, especially regarding mitophagy genetics. Thus, this work investigates the association of 14 variants of the PRKN gene with LD in the treatment of PD. We recruited 70 patients with PD undergoing treatment with LD (39 without dyskinesia and 31 with dyskinesia). Genotyping was based on Sanger sequencing. Our results reinforce that age at onset of symptoms, duration of PD, and treatment and dosage of LD can influence the occurrence of dyskinesia but not the investigated PRKN variants. The perspective presented here of variants of mitophagy-related genes in the context of treatment with LD is still underexplored, although an association has been indicated in previous studies. We suggest that other variants in PRKN or in other mitophagy genes may participate in the development of levodopa-induced dyskinesia in PD treatment.

Keywords:  Parkinson’s disease; levodopa; mitophagy

DOI:  https://doi.org/10.3390/biomedicines11082230
Sheng Wu Gong Cheng Xue Bao. 2023 Aug 25. 39(8): 3464-3480

[Effect of mitophagy related genes on the antioxidant properties of Saccharomyces cerevisiae].

Wanqi Cheng, Qianyao Hou, Chunfeng Liu, Chengtuo Niu, Feiyun Zheng, Qi Li, Jinjing Wang.

  Mitophagy is a process whereby cells selectively remove mitochondria through the mechanism of autophagy, which plays an important role in maintaining cellular homeostasis. In order to explore the effect of mitophagy genes on the antioxidant activities of Saccharomyces cerevisiae, mutants with deletion or overexpression of mitophagy genes ATG8, ATG11 and ATG32 were constructed respectively. The results indicated that overexpression of ATG8 and ATG11 genes significantly reduced the intracellular reactive oxygen species (ROS) content upon H2O2 stress for 6 h, which were 61.23% and 46.35% of the initial state, respectively. Notable, overexpression of ATG8 and ATG11 genes significantly increased the mitochondrial membrane potential (MMP) and ATP content, which were helpful to improve the antioxidant activities of the strains. On the other hand, deletion of ATG8, ATG11 and ATG32 caused mitochondrial damage and significantly decreased cell vitality, and caused the imbalance of intracellular ROS. The intracellular ROS content significantly increased to 174.27%, 128.68%, 200.92% of the initial state, respectively, upon H2O2 stress for 6 h. The results showed that ATG8, ATG11 and ATG32 might be potential targets for regulating the antioxidant properties of yeast, providing a new clue for further research.

Keywords:  ATG genes; antioxidant properties; mitophagy; oxidative stress

DOI:  https://doi.org/10.13345/j.cjb.220860
J Orthop Surg Res. 2023 Aug 24. 18(1): 620

PPARγ activation suppresses chondrocyte ferroptosis through mitophagy in osteoarthritis.

Xiang Xue, Tianming Dai, Junyan Chen, Yangyang Xu, Zhenyu Yang, Jian Huang, Wuyan Xu, Siming Li, Qingqi Meng.

  BACKGROUND: Osteoarthritis (OA) is a prevalent disease plaguing the elderly. Recently, chondrocyte ferroptosis has been demonstrated to promote the progression of OA. Peroxisome proliferator-activated receptor-γ (PPARγ) is an important factor in maintaining cartilage health. However, the relationship between PPARγ and chondrocyte ferroptosis in OA and its mechanism is completely unclear.METHODS: We established a surgically induced knee OA rat model to investigate PPARγ and chondrocyte ferroptosis in OA. Rat knee specimens were collected for Safranin O/Fast Green staining and immunohistochemical staining after administered orally placebo or pioglitazone (PPARγ agonist) for 4 weeks. We used RSL3 to establish a chondrocyte ferroptosis model cultured in vitro to study the role of PPARγ activation toward ferroptosis, mitochondrial function, and PTEN-induced putative kinase 1 (Pink1)/Parkin-dependent mitophagy. GW9662 (PPARγ antagonist), Mdivi-1 (mitophagy inhibitor), and chloroquine (mitophagy inhibitor) were employed to investigate the mechanism of PPARγ-Pink1/Parkin-dependent mitophagy in the inhibition of ferroptosis.
RESULTS: We found that PPARγ activation by pioglitazone attenuated not only OA but also inhibited the expression of the ferroptosis marker acyl-CoA synthetase long-chain family member 4 (ACSL4) at the same time in rats. Furthermore, in vivo and in vitro data indicated that PPARγ activation restored Pink1/Parkin-dependent mitophagy, improved mitochondrial function, inhibited chondrocyte ferroptosis, and delayed the progression of OA.
CONCLUSIONS: The present study demonstrated that PPARγ activation attenuates OA by inhibiting chondrocyte ferroptosis, and this chondroprotective effect was achieved by promoting the Pink1/Parkin-dependent mitophagy pathway.

Keywords:  Chondrocyte; Ferroptosis; Mitophagy; Osteoarthritis; PPARγ; Pink1

DOI:  https://doi.org/10.1186/s13018-023-04092-x
Biomolecules. 2023 Jul 25. pii: 1163. [Epub ahead of print]13(8):

Transcriptome Highlights Cannabinol Modulation of Mitophagy in a Parkinson's Disease In Vitro Model.

Agnese Gugliandolo, Santino Blando, Stefano Salamone, Federica Pollastro, Emanuela Mazzon, Simone D'Angiolini.

  Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra and the accumulation of α-synuclein aggregates, known as Lewy bodies. It is known that mitochondria dysfunctions, including impaired localization, transport and mitophagy, represent features of PD. Cannabinoids are arising as new therapeutic strategies against neurodegenerative diseases. In this study, we aimed to evaluate the potential protective effects of cannabinol (CBN) pre-treatment in an in vitro PD model, namely retinoic acid-differentiated SH-SY5Y neuroblastoma cells treated with 1-methyl-4-phenylpyridinium (MPP+). With this aim, we performed a transcriptomic analysis through next-generation sequencing. We found that CBN counteracted the loss of cell viability caused by MPP+ treatment. Then, we focused on biological processes relative to mitochondria functions and found that CBN pre-treatment was able to attenuate the MPP+-induced changes in the expression of genes involved in mitochondria transport, localization and protein targeting. Notably, MPP+ treatment increased the expression of the genes involved in PINK1/Parkin mitophagy, while CBN pre-treatment reduced their expression. The results suggested that CBN can exert a protection against MPP+ induced mitochondria impairment.

Keywords:  Parkinson’s disease; cannabinol; mitochondria; mitophagy

DOI:  https://doi.org/10.3390/biom13081163
Diabetologia. 2023 Aug 24.

Lipotoxicity-polarised macrophage-derived exosomes regulate mitochondrial fitness through Miro1-mediated mitophagy inhibition and contribute to type 2 diabetes development in mice.

Jian-Ming Li, Xianyu Li, Lawrence W C Chan, Ruinian Hu, Tian Zheng, Haojie Li, Sijun Yang.

  AIMS/HYPOTHESIS: Insulin resistance is a major pathophysiological defect in type 2 diabetes and obesity. Numerous experimental and clinical studies have provided evidence that sustained lipotoxicity-induced mitophagy deficiency can exacerbate insulin resistance, leading to a vicious cycle between mitophagy dysfunction and insulin resistance, and thereby the onset of type 2 diabetes. Emerging evidence suggests that exosomes (Exos) from M2 macrophages play an essential role in modulating metabolic homeostasis. However, how macrophages are affected by lipotoxicity and the role of lipotoxicity in promoting macrophage activation to the M1 state have not been determined. The objective of this study was to determine whether M1 macrophage-derived Exos polarised by lipopolysaccharide (LPS) + palmitic acid (PA)-induced lipotoxicity contribute to metabolic homeostasis and impact the development of insulin resistance in type 2 diabetes.METHODS: Lipotoxicity-polarised macrophage-derived M1 Exos were isolated from bone marrow (C57BL/6J mouse)-derived macrophages treated with LPS+PA. Exos were characterised by transmission electron microscopy, nanoparticle tracking analysis and western blotting. Flow cytometry, H&E staining, quantitative real-time PCR, immunofluorescence, glucose uptake and output assays, confocal microscopy imaging, western blotting, GTTs and ITTs were conducted to investigate tissue inflammation, mitochondrial function and insulin resistance in vitro and in vivo. The roles of miR-27-3p and its target gene Miro1 (also known as Rhot1, encoding mitochondrial rho GTPase 1) and relevant pathways were predicted and assessed in vitro and in vivo using specific miRNA mimic, miRNA inhibitor, miRNA antagomir and siRNA.
RESULTS: miR-27-3p was highly expressed in M1 Exos and functioned as a Miro1-inactivating miRNA through the miR-27-3p-Miro1 axis, leading to mitochondria fission rather than fusion as well as mitophagy impairment, resulting in NOD-like receptor 3 inflammatory activation and development of insulin resistance both in vivo and in vitro. Inactivation of miR-27-3p induced by M1 Exos prevented type 2 diabetes development in high-fat-diet-fed mice.
CONCLUSIONS/INTERPRETATION: These findings suggest that the miR-27-3p-Miro1 axis, as a novel regulatory mechanism for mitophagy, could be considered as a new therapeutic target for lipotoxicity-related type 2 diabetes disease development.

Keywords:  Exosomes; Lipotoxicity; Miro1; Mitochondrial fitness; Mitophagy; Type 2 diabetes

DOI:  https://doi.org/10.1007/s00125-023-05992-7
Antioxidants (Basel). 2023 Aug 10. pii: 1593. [Epub ahead of print]12(8):

Mitochondrial Dysfunction in Repeat Expansion Diseases.

Alberto Giménez-Bejarano, Eva Alegre-Cortés, Sokhna M S Yakhine-Diop, Patricia Gómez-Suaga, José M Fuentes.

  Repeat expansion diseases are a group of neuromuscular and neurodegenerative disorders characterized by expansions of several successive repeated DNA sequences. Currently, more than 50 repeat expansion diseases have been described. These disorders involve diverse pathogenic mechanisms, including loss-of-function mechanisms, toxicity associated with repeat RNA, or repeat-associated non-ATG (RAN) products, resulting in impairments of cellular processes and damaged organelles. Mitochondria, double membrane organelles, play a crucial role in cell energy production, metabolic processes, calcium regulation, redox balance, and apoptosis regulation. Its dysfunction has been implicated in the pathogenesis of repeat expansion diseases. In this review, we provide an overview of the signaling pathways or proteins involved in mitochondrial functioning described in these disorders. The focus of this review will be on the analysis of published data related to three representative repeat expansion diseases: Huntington's disease, C9orf72-frontotemporal dementia/amyotrophic lateral sclerosis, and myotonic dystrophy type 1. We will discuss the common effects observed in all three repeat expansion disorders and their differences. Additionally, we will address the current gaps in knowledge and propose possible new lines of research. Importantly, this group of disorders exhibit alterations in mitochondrial dynamics and biogenesis, with specific proteins involved in these processes having been identified. Understanding the underlying mechanisms of mitochondrial alterations in these disorders can potentially lead to the development of neuroprotective strategies.

Keywords:  C9orf72; Ca2+, mitophagy; Huntington disease; ROS; apoptosis; myotonic dystrophy type 1

DOI:  https://doi.org/10.3390/antiox12081593
Cell Death Dis. 2023 08 22. 14(8): 540

The deubiquitinase Leon/USP5 interacts with Atg1/ULK1 and antagonizes autophagy.

Yueh-Ling Pai, Yuchieh Jay Lin, Wen-Hsin Peng, Li-Ting Huang, He-Yen Chou, Chien-Hsiang Wang, Cheng-Ting Chien, Guang-Chao Chen.

Accumulating evidence has shown that the quality of proteins must be tightly monitored and controlled to maintain cellular proteostasis. Misfolded proteins and protein aggregates are targeted for degradation through the ubiquitin proteasome (UPS) and autophagy-lysosome systems. The ubiquitination and deubiquitinating enzymes (DUBs) have been reported to play pivotal roles in the regulation of the UPS system. However, the function of DUBs in the regulation of autophagy remain to be elucidated. In this study, we found that knockdown of Leon/USP5 caused a marked increase in the formation of autophagosomes and autophagic flux under well-fed conditions. Genetic analysis revealed that overexpression of Leon suppressed Atg1-induced cell death in Drosophila. Immunoblotting assays further showed a strong interaction between Leon/USP5 and the autophagy initiating kinase Atg1/ULK1. Depletion of Leon/USP5 led to increased levels of Atg1/ULK1. Our findings indicate that Leon/USP5 is an autophagic DUB that interacts with Atg1/ULK1, negatively regulating the autophagic process.

DOI: https://doi.org/10.1038/s41419-023-06062-x
Neuroscience. 2023 Aug 23. pii: S0306-4522(23)00338-X. [Epub ahead of print]

Transcription Factor Forkhead Box P (Foxp) 1 Reduces Brain Damage During Cerebral Ischemia-Reperfusion Injury in Mice Through FUNDC1.

Yang Li, Yang Changhong, Yang Liyu, Meng Changchang, Linggao Zeng, Li Yue, Zhao Jing.

  Mitophagy plays a significant role in modulating the activation of pyrin domain-containing protein 3 (NLRP3) inflammasome, which is a major contributor to the inflammatory response that exacerbates cerebral ischemia-reperfusion (I/R) injury. Despite this, the transcriptional regulation mechanism that governs mitophagy remains unclear. This study sought to explore the potential mechanism of Forkhead Box P1 (Foxp1) and its impact on cerebral I/R injury. We investigated the potential neuroprotective role of Foxp1 in cerebral I/R injury by the middle cerebral artery occlusion (MCAO) mouse model. Additionally, we assessed whether FUN14 domain-containing protein 1 (FUNDC1) could rescue the protective effect of Foxp1. Our results showed that overexpression of Foxp1 prevented brain damage during cerebral I/R injury and promoted NLRP3 inflammasome activation, whereas knockdown of Foxp1 had the opposite effect. Notably, Foxp1 overexpression directly promotes FUNDC1 expression, enhanced mitophagy activation, and inhibited the inflammatory response mediated by the NLRP3 inflammasome. Furthermore, we confirmed through chromatin immunoprecipitation (ChIP) and luciferase reporter assays that FUNDC1 is a direct target gene of Foxp1 downstream. Furthermore, the knockdown of FUNDC1 reversed the increased activation of mitophagy and suppressed NLRP3 inflammasome activation induced by Foxp1 overexpression. Collectively, our findings suggest that Foxp1 inhibits NLRP3 inflammasome activation through FUNDC1 to reduce cerebral I/R injury.

Keywords:  FUN14 domain-containing protein 1; Nod-like receptor protein 3 inflammasome; cerebral ischemia/reperfusion; forkhead Box P 1; mitochondrial autophagy

DOI:  https://doi.org/10.1016/j.neuroscience.2023.07.029
Antioxidants (Basel). 2023 Aug 18. pii: 1635. [Epub ahead of print]12(8):

SIRT5 Activation and Inorganic Phosphate Binding Reduce Cancer Cell Vitality by Modulating Autophagy/Mitophagy and ROS.

Federica Barreca, Michele Aventaggiato, Laura Vitiello, Luigi Sansone, Matteo Antonio Russo, Antonello Mai, Sergio Valente, Marco Tafani.

  Cancer cells show increased glutamine consumption. The glutaminase (GLS) enzyme controls a limiting step in glutamine catabolism. Breast tumors, especially the triple-negative subtype, have a high expression of GLS. Our recent study demonstrated that GLS activity and ammonia production are inhibited by sirtuin 5 (SIRT5). We developed MC3138, a selective SIRT5 activator. Treatment with MC3138 mimicked the deacetylation effect mediated by SIRT5 overexpression. Moreover, GLS activity was regulated by inorganic phosphate (Pi). Considering the interconnected roles of GLS, SIRT5 and Pi in cancer growth, our hypothesis is that activation of SIRT5 and reduction in Pi could represent a valid antitumoral strategy. Treating cells with MC3138 and lanthanum acetate, a Pi chelator, decreased cell viability and clonogenicity. We also observed a modulation of MAP1LC3B and ULK1 with MC3138 and lanthanum acetate. Interestingly, inhibition of the mitophagy marker BNIP3 was observed only in the presence of MC3138. Autophagy and mitophagy modulation were accompanied by an increase in cytosolic and mitochondrial reactive oxygen species (ROS). In conclusion, our results show how SIRT5 activation and/or Pi binding can represent a valid strategy to inhibit cell proliferation by reducing glutamine metabolism and mitophagy, leading to a deleterious accumulation of ROS.

Keywords:  ROS; autophagy; glutaminase; glutamine; hypoxia; mitophagy; sirtuins

DOI:  https://doi.org/10.3390/antiox12081635