bims-mitmed Biomed News
on Mitochondrial medicine
Issue of 2024–03–10
25 papers selected by
Dario Brunetti, Fondazione IRCCS Istituto Neurologico
  1. Hallmark Molecular and Pathological Features of POLG Disease are Recapitulated in Cerebral Organoids.
  2. The interplay between mitochondrial dynamics and autophagy: From a key homeostatic mechanism to a driver of pathology.
  3. Charcot-Marie-tooth disease type 2A: An update on pathogenesis and therapeutic perspectives.
  4. Mitochondrial metabolism in neural stem cells and implications for neurodevelopmental and neurodegenerative diseases.
  5. Identification of a novel MT-ND3 variant and restoring mitochondrial function by allotopic expression of MT-ND3 gene.
  6. Mitochondrial dysfunction in the pathophysiology of renal diseases.
  7. Mitochondrial DNA marks multiple sclerosis.
  8. Generation of a human induced pluripotent stem cell line NTUHi004-A from a patient with Leigh syndrome harboring a homozygous missense mutation c.836 T > G (p.Met279Arg) in NDUFAF5 gene.
  9. Mitochondrial DNA mutations in Korean patients with Leber's hereditary optic neuropathy.
  10. Activity-dependent compartmentalization of dendritic mitochondria morphology through local regulation of fusion-fission balance in neurons in vivo.
  11. Two ancient membrane pores mediate mitochondrial-nucleus membrane contact sites.
  12. Mitochondrial myopathies diagnosed in adulthood: clinico-genetic spectrum and long-term outcomes.
  13. Kinase signalling adaptation supports dysfunctional mitochondria in disease.
  14. A mitochondrial NADPH-cholesterol axis regulates extracellular vesicle biogenesis to support hematopoietic stem cell fate.
  15. NDUFS4 regulates cristae remodeling in diabetic kidney disease.
  16. Integrated stress response signaling acts as a metabolic sensor in fat tissues to regulate oocyte maturation and ovulation.
  17. Targeting mitochondrial dynamics and redox regulation in cardiovascular diseases.
  18. Loss of WIPI4 in neurodegeneration causes autophagy-independent ferroptosis.
  19. Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing.
  20. Aging-induced tRNAGlu-derived fragment impairs glutamate biosynthesis by targeting mitochondrial translation-dependent cristae organization.
  21. The lysosomal β-glucocerebrosidase strikes mitochondria: implications for Parkinson's therapeutics.
  22. Mechanism of proton-powered c-ring rotation in a mitochondrial ATP synthase.
  23. Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids.
  24. Mitochondrial disorders leading to Alzheimer's disease-perspectives of diagnosis and treatment.
  25. A humanized mouse model for adeno-associated viral gene therapy.
  1. Adv Sci (Weinh). 2024 Mar 06. e2307136
    Hallmark Molecular and Pathological Features of POLG Disease are Recapitulated in Cerebral Organoids.
    Anbin Chen, Tsering Yangzom, Yu Hong, Bjørn Christian Lundberg, Gareth John Sullivan, Charalampos Tzoulis, Laurence A Bindoff, Kristina Xiao Liang.
      In this research, a 3D brain organoid model is developed to study POLG-related encephalopathy, a mitochondrial disease stemming from POLG mutations. Induced pluripotent stem cells (iPSCs) derived from patients with these mutations is utilized to generate cortical organoids, which exhibited typical features of the diseases with POLG mutations, such as altered morphology, neuronal loss, and mitochondiral DNA (mtDNA) depletion. Significant dysregulation is also identified in pathways crucial for neuronal development and function, alongside upregulated NOTCH and JAK-STAT signaling pathways. Metformin treatment ameliorated many of these abnormalities, except for the persistent affliction of inhibitory dopamine-glutamate (DA GLU) neurons. This novel model effectively mirrors both the molecular and pathological attributes of diseases with POLG mutations, providing a valuable tool for mechanistic understanding and therapeutic screening for POLG-related disorders and other conditions characterized by compromised neuronal mtDNA maintenance and complex I deficiency.
    Keywords:  POLG; cortical organoids; iPSC; mitochondrial function; neuron
    DOI:  https://doi.org/10.1002/advs.202307136
  2. Semin Cell Dev Biol. 2024 Mar 01. pii: S1084-9521(24)00022-3. [Epub ahead of print]161-162 1-19
    The interplay between mitochondrial dynamics and autophagy: From a key homeostatic mechanism to a driver of pathology.
    Alice Lacombe, Luca Scorrano.
      The complex relationship between mitochondrial dynamics and autophagy illustrates how two cellular housekeeping processes are intimately linked, illuminating fundamental principles of cellular homeostasis and shedding light on disparate pathological conditions including several neurodegenerative disorders. Here we review the basic tenets of mitochondrial dynamics i.e., the concerted balance between fusion and fission of the organelle, and its interplay with macroautophagy and selective mitochondrial autophagy, also dubbed mitophagy, in the maintenance of mitochondrial quality control and ultimately in cell viability. We illustrate how conditions of altered mitochondrial dynamics reverberate on autophagy and vice versa. Finally, we illustrate how altered interplay between these two key cellular processes participates in the pathogenesis of human disorders affecting multiple organs and systems.
    Keywords:  Mitochondria; autophagy; diseases; fusion-fission; mitophagy
    DOI:  https://doi.org/10.1016/j.semcdb.2024.02.001
  3. Neurobiol Dis. 2024 Mar 05. pii: S0969-9961(24)00066-4. [Epub ahead of print] 106467
    Charcot-Marie-tooth disease type 2A: An update on pathogenesis and therapeutic perspectives.
    Claudia Alberti, Federica Rizzo, Alessia Anastasia, Giacomo Comi, Stefania Corti, Elena Abati.
      Mutations in the gene encoding MFN2 have been identified as associated with Charcot-Marie-Tooth disease type 2A (CMT2A), a neurological disorder characterized by a broad clinical phenotype involving the entire nervous system. MFN2, a dynamin-like GTPase protein located on the outer mitochondrial membrane, is well-known for its involvement in mitochondrial fusion. Numerous studies have demonstrated its participation in a network crucial for various other mitochondrial functions, including mitophagy, axonal transport, and its controversial role in endoplasmic reticulum (ER)-mitochondria contacts. Considerable progress has been made in the last three decades in elucidating the disease pathogenesis, aided by the generation of animal and cellular models that have been instrumental in studying disease physiology. A review of the literature reveals that, up to now, no definitive pharmacological treatment for any CMT2A variant has been established; nonetheless, recent years have witnessed substantial progress. Many treatment approaches, especially concerning molecular therapy, such as histone deacetylase inhibitors, peptide therapy to increase mitochondrial fusion, the new therapeutic strategies based on MF1/MF2 balance, and SARM1 inhibitors, are currently in preclinical testing. The literature on gene silencing and gene replacement therapies is still limited, except for a recent study by Rizzo et al.(Rizzo et al., 2023), which recently first achieved encouraging results in in vitro and in vivo models of the disease. The near-future goal for these promising therapies is to progress to the stage of clinical translation.
    Keywords:  CMT2A; MFN2; Mitofusin 2; Pathogenesis; Treatment
    DOI:  https://doi.org/10.1016/j.nbd.2024.106467
  4. J Transl Med. 2024 Mar 04. 22(1): 238
    Mitochondrial metabolism in neural stem cells and implications for neurodevelopmental and neurodegenerative diseases.
    C Garone, F De Giorgio, S Carli.
      Mitochondria are cytoplasmic organelles having a fundamental role in the regulation of neural stem cell (NSC) fate during neural development and maintenance.During embryonic and adult neurogenesis, NSCs undergo a metabolic switch from glycolytic to oxidative phosphorylation with a rise in mitochondrial DNA (mtDNA) content, changes in mitochondria shape and size, and a physiological augmentation of mitochondrial reactive oxygen species which together drive NSCs to proliferate and differentiate. Genetic and epigenetic modifications of proteins involved in cellular differentiation (Mechanistic Target of Rapamycin), proliferation (Wingless-type), and hypoxia (Mitogen-activated protein kinase)-and all connected by the common key regulatory factor Hypoxia Inducible Factor-1A-are deemed to be responsible for the metabolic shift and, consequently, NSC fate in physiological and pathological conditions.Both primary mitochondrial dysfunction due to mutations in nuclear DNA or mtDNA or secondary mitochondrial dysfunction in oxidative phosphorylation (OXPHOS) metabolism, mitochondrial dynamics, and organelle interplay pathways can contribute to the development of neurodevelopmental or progressive neurodegenerative disorders.This review analyses the physiology and pathology of neural development starting from the available in vitro and in vivo models and highlights the current knowledge concerning key mitochondrial pathways involved in this process.
    Keywords:  HIF-1A; Mitochondrial metabolism; Neurodegenerative disorders; Neuronal development; Stem cells; Wnt; mTOR
    DOI:  https://doi.org/10.1186/s12967-024-05041-w
  5. Mitochondrion. 2024 Mar 02. pii: S1567-7249(24)00016-3. [Epub ahead of print] 101858
    Identification of a novel MT-ND3 variant and restoring mitochondrial function by allotopic expression of MT-ND3 gene.
    Nurun Nahar Borna, Yoshihito Kishita, Masaru Shimura, Kei Murayama, Akira Ohtake, Yasushi Okazaki.
      Mitochondrial diseases are caused by nuclear, or mitochondrial DNA (mtDNA) variants and related co-factors. Here, we report a novel m.10197G > C variant in MT-ND3 in a patient, and two other patients with m.10191 T > C. MT-ND3 variants are known to cause Leigh syndrome or mitochondrial complex I deficiency. We performed the functional analyses of the novel m.10197G > C variant that significantly lowered MT-ND3 protein levels, causing complex I assembly and activity deficiency, and reduction of ATP synthesis. We adapted a previously described re-engineering technique of delivering mitochondrial genes into mitochondria through codon optimization for nuclear expression and translation by cytoplasmic ribosomes to rescue defects arising from the MT-ND3 variants. We constructed mitochondrial targeting sequences along with the codon-optimized MT-ND3 and imported them into the mitochondria. To achieve the goal, we imported codon-optimized MT-ND3 into mitochondria in three patients with m.10197G > C and m.10191 T > C missense variants in the MT-ND3. Nuclear expression of the MT-ND3 gene partially restored protein levels, complex I deficiency, and significant improvement of ATP production indicating a functional rescue of the mutant phenotype. The codon-optimized nuclear expression of mitochondrial protein and import inside the mitochondria can supplement the requirements for ATP in energy-deficient mitochondrial disease patients.
    Keywords:  Allotopic expression; Codon-optimization; Leigh Syndrome; MT-ND3; Mitochondrial DNA
    DOI:  https://doi.org/10.1016/j.mito.2024.101858
  6. Am J Physiol Renal Physiol. 2024 Mar 07.
    Mitochondrial dysfunction in the pathophysiology of renal diseases.
    Yuxian Guo, Ruochen Che, Peipei Wang, Aihua Zhang.
      Mitochondria are essential organelles in the human body, serving as the metabolic factory of the whole organism. When mitochondria are dysfunctional, it can affect all organs of the body. The kidney is rich in mitochondria, and its function is closely related to the development of kidney diseases. Studying the relationship between mitochondria and kidney disease progression is of great interest. In the past decade, scientists have made inspiring progress in investigating the role of mitochondria in the pathophysiology of renal diseases. This article discusses various mechanisms for maintaining mitochondrial quality, including mitochondrial energetics, mitochondrial biogenesis, mitochondrial dynamics, mitochondrial DNA repair, mitochondrial proteolysis and UPR, mitochondrial autophagy, mitochondria-derived vesicles, and mitocytosis. The article also highlights the crosstalk between mitochondria and other organelles, with a focus on kidney diseases. Finally, the article concludes with an overview of mitochondrial-related clinical research.
    DOI:  https://doi.org/10.1152/ajprenal.00189.2023
  7. Nat Rev Neurol. 2024 Mar 05.
    Mitochondrial DNA marks multiple sclerosis.
    Ian Fyfe.
      
    DOI:  https://doi.org/10.1038/s41582-024-00948-w
  8. Stem Cell Res. 2024 Mar 05. pii: S1873-5061(24)00077-1. [Epub ahead of print]76 103379
    Generation of a human induced pluripotent stem cell line NTUHi004-A from a patient with Leigh syndrome harboring a homozygous missense mutation c.836 T > G (p.Met279Arg) in NDUFAF5 gene.
    Chih-Hsin Ou-Yang, Pin-Shiuan Chen, Chin-Hsien Lin.
      Leigh syndrome is a rare autosomal recessive disorder showcasing a diverse range of neurological symptoms. Classical Leigh syndrome is associated with mitochondrial complex I deficiency, primarily resulting from biallelic mutations in the NDUFAF5 gene, encoding the NADH:ubiquinone oxidoreductase complex assembly factor 5. Using the Sendai virus delivery system, we generated an induced pluripotent stem cell line from peripheral blood mononuclear cells of a 47-years-old female patient who carried a homozygous NDUFAF5 c.836 T > G (p.Met279Arg) mutation. This cellular model serves as a tool for investigating the underlying pathogenic mechanisms and for the development of potential treatments for Leigh syndrome.
    DOI:  https://doi.org/10.1016/j.scr.2024.103379
  9. Sci Rep. 2024 Mar 08. 14(1): 5702
    Mitochondrial DNA mutations in Korean patients with Leber's hereditary optic neuropathy.
    Hee Kyung Yang, Moon-Woo Seong, Jeong-Min Hwang.
      In order to explore the spectrum of mitochondrial DNA (mtDNA) mutations in Korean patients with Leber's hereditary optic neuropathy (LHON), we investigated the spectrum of mtDNA mutations in 145 Korean probands confirmed with the diagnosis of LHON. Total genomic DNA was isolated from the peripheral blood leukocytes of the patients with suspected LHON, and mtDNA mutations were identified by direct sequencing. Analysis of mtDNA mutations revealed seven primary LHON mutations including the nucleotide positions (nps) 11778A (101 probands, 69.2%), 14484C (31 probands, 21.2%), 3460A (5 probands, 3.4%), and G3635A, G3733A, C4171A, and G13051A mutations in one proband each. In addition, two provisional mtDNA mutations at nps T3472C, and G13259A were each found in one proband, respectively. Another provisional mtDNA mutation at np T3394C was found in two probands. In conclusion, the spectrum of mtDNA mutations in Korean patients with LHON may differ from other ethnicities, which is characterized by high prevalence of 11778A and 14484C mutations, and a low prevalence of the 3460A mutation.
    Keywords:  Koreans; Leber’s hereditary optic neuropathy; Mitochondrial DNA mutation; Spectrum
    DOI:  https://doi.org/10.1038/s41598-024-56215-x
  10. Nat Commun. 2024 Mar 08. 15(1): 2142
    Activity-dependent compartmentalization of dendritic mitochondria morphology through local regulation of fusion-fission balance in neurons in vivo.
    Daniel M Virga, Stevie Hamilton, Bertha Osei, Abigail Morgan, Parker Kneis, Emiliano Zamponi, Natalie J Park, Victoria L Hewitt, David Zhang, Kevin C Gonzalez, Fiona M Russell, D Grahame Hardie, Julien Prudent, Erik Bloss, Attila Losonczy, Franck Polleux, Tommy L Lewis.
      Neuronal mitochondria play important roles beyond ATP generation, including Ca2+ uptake, and therefore have instructive roles in synaptic function and neuronal response properties. Mitochondrial morphology differs significantly between the axon and dendrites of a given neuronal subtype, but in CA1 pyramidal neurons (PNs) of the hippocampus, mitochondria within the dendritic arbor also display a remarkable degree of subcellular, layer-specific compartmentalization. In the dendrites of these neurons, mitochondria morphology ranges from highly fused and elongated in the apical tuft, to more fragmented in the apical oblique and basal dendritic compartments, and thus occupy a smaller fraction of dendritic volume than in the apical tuft. However, the molecular mechanisms underlying this striking degree of subcellular compartmentalization of mitochondria morphology are unknown, precluding the assessment of its impact on neuronal function. Here, we demonstrate that this compartment-specific morphology of dendritic mitochondria requires activity-dependent, Ca2+ and Camkk2-dependent activation of AMPK and its ability to phosphorylate two direct effectors: the pro-fission Drp1 receptor Mff and the recently identified anti-fusion, Opa1-inhibiting protein, Mtfr1l. Our study uncovers a signaling pathway underlying the subcellular compartmentalization of mitochondrial morphology in dendrites of neurons in vivo through spatially precise and activity-dependent regulation of mitochondria fission/fusion balance.
    DOI:  https://doi.org/10.1038/s41467-024-46463-w
  11. J Cell Biol. 2024 Apr 01. pii: e202304075. [Epub ahead of print]223(4):
    Two ancient membrane pores mediate mitochondrial-nucleus membrane contact sites.
    Jana Ovciarikova, Shikha Shikha, Alice Lacombe, Flavie Courjol, Rosalind McCrone, Wasim Hussain, Andrew Maclean, Leandro Lemgruber, Erica S Martins-Duarte, Mathieu Gissot, Lilach Sheiner.
      Coordination between nucleus and mitochondria is essential for cell survival, and thus numerous communication routes have been established between these two organelles over eukaryotic cell evolution. One route for organelle communication is via membrane contact sites, functional appositions formed by molecular tethers. We describe a novel nuclear-mitochondrial membrane contact site in the protozoan Toxoplasma gondii. We have identified specific contacts occurring at the nuclear pore and demonstrated an interaction between components of the nuclear pore and the mitochondrial protein translocon, highlighting them as molecular tethers. Genetic disruption of the nuclear pore or the TOM translocon components, TgNup503 or TgTom40, respectively, result in contact site reduction, supporting their potential involvement in this tether. TgNup503 depletion further leads to specific mitochondrial morphology and functional defects, supporting a role for nuclear-mitochondrial contacts in mediating their communication. The discovery of a contact formed through interaction between two ancient mitochondrial and nuclear complexes sets the ground for better understanding of mitochondrial-nuclear crosstalk in eukaryotes.
    DOI:  https://doi.org/10.1083/jcb.202304075
  12. Brain Commun. 2024 ;6(2): fcae041
    Mitochondrial myopathies diagnosed in adulthood: clinico-genetic spectrum and long-term outcomes.
    Grayson Beecher, Ralitza H Gavrilova, Jay Mandrekar, Elie Naddaf.
      Mitochondrial myopathies are frequently recognized in childhood as part of a broader multisystem disorder and often overlooked in adulthood. Herein, we describe the phenotypic and genotypic spectrum and long-term outcomes of mitochondrial myopathies diagnosed in adulthood, focusing on neuromuscular features, electrodiagnostic and myopathological findings and survival. We performed a retrospective chart review of adult patients diagnosed with mitochondrial myopathy at Mayo Clinic (2005-21). We identified 94 patients. Median time from symptom onset to diagnosis was 11 years (interquartile range 4-21 years). Median age at diagnosis was 48 years (32-63 years). Primary genetic defects were identified in mitochondrial DNA in 48 patients (10 with single large deletion, 38 with point mutations) and nuclear DNA in 29. Five patients had multiple mitochondrial DNA deletions or depletion without nuclear DNA variants. Twelve patients had histopathological features of mitochondrial myopathy without molecular diagnosis. The most common phenotypes included multisystem disorder (n = 30); mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (14); limb myopathy (13); chronic progressive external ophthalmoplegia (12); and chronic progressive external ophthalmoplegia-plus (12). Isolated skeletal muscle manifestations occurred in 27%. Sixty-nine per cent had CNS and 21% had cardiac involvement. Mutations most frequently involved MT-TL1 (27) and POLG (17); however, a wide spectrum of established and novel molecular defects, with overlapping phenotypes, was identified. Electrodiagnostic studies identified myopathy (77%), fibrillation potentials (27%) and axonal peripheral neuropathy (42%, most common with nuclear DNA variants). Among 42 muscle biopsies available, median percentage counts were highest for cytochrome C oxidase negative fibres (5.1%) then ragged blue (1.4%) and ragged red fibres (0.5%). Skeletal muscle weakness was mild and slowly progressive (decline in strength summated score of 0.01/year). Median time to gait assistance was 5.5 years from diagnosis and 17 years from symptom onset. Thirty patients died, with median survival of 33.4 years from symptom onset and 10.9 years from diagnosis. Median age at death was 55 years. Cardiac involvement was associated with increased mortality [hazard ratio 2.36 (1.05, 5.29)]. There was no difference in survival based on genotype or phenotype. Despite the wide phenotypic and genotypic spectrum, mitochondrial myopathies in adults share similar features with slowly progressive limb weakness, contrasting with common multiorgan involvement and high mortality.
    Keywords:  MELAS; POLG; chronic progressive external ophthalmoplegia; inherited myopathies; mitochondrial myopathies
    DOI:  https://doi.org/10.1093/braincomms/fcae041
  13. Front Mol Biosci. 2024 ;11 1354682
    Kinase signalling adaptation supports dysfunctional mitochondria in disease.
    George L Skalka, Mina Tsakovska, Daniel J Murphy.
      Mitochondria form a critical control nexus which are essential for maintaining correct tissue homeostasis. An increasing number of studies have identified dysregulation of mitochondria as a driver in cancer. However, which pathways support and promote this adapted mitochondrial function? A key hallmark of cancer is perturbation of kinase signalling pathways. These pathways include mitogen activated protein kinases (MAPK), lipid secondary messenger networks, cyclic-AMP-activated (cAMP)/AMP-activated kinases (AMPK), and Ca2+/calmodulin-dependent protein kinase (CaMK) networks. These signalling pathways have multiple substrates which support initiation and persistence of cancer. Many of these are involved in the regulation of mitochondrial morphology, mitochondrial apoptosis, mitochondrial calcium homeostasis, mitochondrial associated membranes (MAMs), and retrograde ROS signalling. This review will aim to both explore how kinase signalling integrates with these critical mitochondrial pathways and highlight how these systems can be usurped to support the development of disease. In addition, we will identify areas which require further investigation to fully understand the complexities of these regulatory interactions. Overall, this review will emphasize how studying the interaction between kinase signalling and mitochondria improves our understanding of mitochondrial homeostasis and can yield novel therapeutic targets to treat disease.
    Keywords:  apoptosis; disease adaptation; kinase; mitochondria; mitochondrial associated endoplasmic reticulum membranes (MAMs); mitochondrial morphology; reactive oxygen species (ROS)
    DOI:  https://doi.org/10.3389/fmolb.2024.1354682
  14. Cell Stem Cell. 2024 Mar 07. pii: S1934-5909(24)00047-X. [Epub ahead of print]31(3): 359-377.e10
    A mitochondrial NADPH-cholesterol axis regulates extracellular vesicle biogenesis to support hematopoietic stem cell fate.
    Massimo Bonora, Claudia Morganti, Nick van Gastel, Kyoko Ito, Enrica Calura, Ilaria Zanolla, Letizia Ferroni, Yang Zhang, Yookyung Jung, Gabriele Sales, Paolo Martini, Takahisa Nakamura, Francesco Massimo Lasorsa, Toren Finkel, Charles P Lin, Barbara Zavan, Paolo Pinton, Irene Georgakoudi, Chiara Romualdi, David T Scadden, Keisuke Ito.
      Mitochondrial fatty acid oxidation (FAO) is essential for hematopoietic stem cell (HSC) self-renewal; however, the mechanism by which mitochondrial metabolism controls HSC fate remains unknown. Here, we show that within the hematopoietic lineage, HSCs have the largest mitochondrial NADPH pools, which are required for proper HSC cell fate and homeostasis. Bioinformatic analysis of the HSC transcriptome, biochemical assays, and genetic inactivation of FAO all indicate that FAO-generated NADPH fuels cholesterol synthesis in HSCs. Interference with FAO disturbs the segregation of mitochondrial NADPH toward corresponding daughter cells upon single HSC division. Importantly, we have found that the FAO-NADPH-cholesterol axis drives extracellular vesicle (EV) biogenesis and release in HSCs, while inhibition of EV signaling impairs HSC self-renewal. These data reveal the existence of a mitochondrial NADPH-cholesterol axis for EV biogenesis that is required for hematopoietic homeostasis and highlight the non-stochastic nature of HSC fate determination.
    Keywords:  HSC self-renewal; NADPH; cholesterol; exosomes; extracellular vesicles; fate determination; fatty acid oxidation; hematopoietic stem cell; metabolism; mitochondria
    DOI:  https://doi.org/10.1016/j.stem.2024.02.004
  15. Nat Commun. 2024 Mar 04. 15(1): 1965
    NDUFS4 regulates cristae remodeling in diabetic kidney disease.
    Koki Mise, Jianyin Long, Daniel L Galvan, Zengchun Ye, Guizhen Fan, Rajesh Sharma, Irina I Serysheva, Travis I Moore, Collene R Jeter, M Anna Zal, Motoo Araki, Jun Wada, Paul T Schumacker, Benny H Chang, Farhad R Danesh.
      The mitochondrial electron transport chain (ETC) is a highly adaptive process to meet metabolic demands of the cell, and its dysregulation has been associated with diverse clinical pathologies. However, the role and nature of impaired ETC in kidney diseases remains poorly understood. Here, we generate diabetic mice with podocyte-specific overexpression of Ndufs4, an accessory subunit of mitochondrial complex I, as a model investigate the role of ETC integrity in diabetic kidney disease (DKD). We find that conditional male mice with genetic overexpression of Ndufs4 exhibit significant improvements in cristae morphology, mitochondrial dynamics, and albuminuria. By coupling proximity labeling with super-resolution imaging, we also identify the role of cristae shaping protein STOML2 in linking NDUFS4 with improved cristae morphology. Together, we provide the evidence on the central role of NDUFS4 as a regulator of cristae remodeling and mitochondrial function in kidney podocytes. We propose that targeting NDUFS4 represents a promising approach to slow the progression of DKD.
    DOI:  https://doi.org/10.1038/s41467-024-46366-w
  16. Cell Rep. 2024 Mar 06. pii: S2211-1247(24)00191-8. [Epub ahead of print]43(3): 113863
    Integrated stress response signaling acts as a metabolic sensor in fat tissues to regulate oocyte maturation and ovulation.
    Lydia Grmai, Manuel Michaca, Emily Lackner, Narayanan Nampoothiri V P, Deepika Vasudevan.
      Reproduction is an energy-intensive process requiring systemic coordination. However, the inter-organ signaling mechanisms that relay nutrient status to modulate reproductive output are poorly understood. Here, we use Drosophila melanogaster as a model to establish the integrated stress response (ISR) transcription factor, Atf4, as a fat tissue metabolic sensor that instructs oogenesis. We demonstrate that Atf4 regulates lipase activity to mediate yolk lipoprotein synthesis in the fat body. Depletion of Atf4 in the fat body also blunts oogenesis recovery after amino acid deprivation and re-feeding, suggestive of a nutrient-sensing role for Atf4. We also discovered that Atf4 promotes secretion of a fat-body-derived neuropeptide, CNMamide, which modulates neural circuits that promote egg-laying behavior (ovulation). Thus, we posit that ISR signaling in fat tissue acts as a "metabolic sensor" that instructs female reproduction-directly by impacting yolk lipoprotein production and follicle maturation and systemically by regulating ovulation.
    Keywords:  Atf4; CNMa; CP: Cell biology; CP: Developmental biology; adipocyte; bmm; egg retention; integrated stress response; oogenesis; ovulation; yolk protein
    DOI:  https://doi.org/10.1016/j.celrep.2024.113863
  17. Trends Pharmacol Sci. 2024 Mar 07. pii: S0165-6147(24)00028-2. [Epub ahead of print]
    Targeting mitochondrial dynamics and redox regulation in cardiovascular diseases.
    Mirza Ahmar Beg, Minqi Huang, Lance Vick, K N Shashanka Rao, Jue Zhang, Yiliang Chen.
      Accumulating evidence highlights the pivotal role of mitochondria in cardiovascular diseases (CVDs). Understanding the molecular mechanisms underlying mitochondrial dysfunction is crucial for developing targeted therapeutics. Recent years have seen substantial advancements in unraveling mitochondrial regulatory pathways in both normal and pathological states and the development of potent drugs. However, specific delivery of drugs into the mitochondria is still a challenge. We present recent findings on regulators of mitochondrial dynamics and reactive oxygen species (ROS), critical factors influencing mitochondrial function in CVDs. We also discuss advancements in drug delivery strategies aimed at overcoming the technical barrier in targeting mitochondria for CVD treatment.
    Keywords:  atherosclerosis; cardiovascular disease; drug delivery; fission/fusion; mitochondria; reactive oxygen species
    DOI:  https://doi.org/10.1016/j.tips.2024.02.001
  18. Nat Cell Biol. 2024 Mar 07.
    Loss of WIPI4 in neurodegeneration causes autophagy-independent ferroptosis.
    Ye Zhu, Motoki Fujimaki, Louisa Snape, Ana Lopez, Angeleen Fleming, David C Rubinsztein.
      β-Propeller protein-associated neurodegeneration (BPAN) is a rare X-linked dominant disease, one of several conditions that manifest with neurodegeneration and brain iron accumulation. Mutations in the WD repeat domain 45 (WDR45) gene encoding WIPI4 lead to loss of function in BPAN but the cellular mechanisms of how these trigger pathology are unclear. The prevailing view in the literature is that BPAN is simply the consequence of autophagy deficiency given that WIPI4 functions in this degradation pathway. However, our data indicate that WIPI4 depletion causes ferroptosis-a type of cell death induced by lipid peroxidation-via an autophagy-independent mechanism, as demonstrated both in cell culture and in zebrafish. WIPI4 depletion increases ATG2A localization at endoplasmic reticulum-mitochondrial contact sites, which enhances phosphatidylserine import into mitochondria. This results in increased mitochondrial synthesis of phosphatidylethanolamine, a major lipid prone to peroxidation, thus enabling ferroptosis. This mechanism has minimal overlap with classical ferroptosis stimuli but provides insights into the causes of neurodegeneration in BPAN and may provide clues for therapeutic strategies.
    DOI:  https://doi.org/10.1038/s41556-024-01373-3
  19. Nat Commun. 2024 Mar 02. 15(1): 1931
    Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing.
    Martha M Zarou, Kevin M Rattigan, Daniele Sarnello, Engy Shokry, Amy Dawson, Angela Ianniciello, Karen Dunn, Mhairi Copland, David Sumpton, Alexei Vazquez, G Vignir Helgason.
      Supporting cell proliferation through nucleotide biosynthesis is an essential requirement for cancer cells. Hence, inhibition of folate-mediated one carbon (1C) metabolism, which is required for nucleotide synthesis, has been successfully exploited in anti-cancer therapy. Here, we reveal that mitochondrial folate metabolism is upregulated in patient-derived leukaemic stem cells (LSCs). We demonstrate that inhibition of mitochondrial 1C metabolism through impairment of de novo purine synthesis has a cytostatic effect on chronic myeloid leukaemia (CML) cells. Consequently, changes in purine nucleotide levels lead to activation of AMPK signalling and suppression of mTORC1 activity. Notably, suppression of mitochondrial 1C metabolism increases expression of erythroid differentiation markers. Moreover, we find that increased differentiation occurs independently of AMPK signalling and can be reversed through reconstitution of purine levels and reactivation of mTORC1. Of clinical relevance, we identify that combination of 1C metabolism inhibition with imatinib, a frontline treatment for CML patients, decreases the number of therapy-resistant CML LSCs in a patient-derived xenograft model. Our results highlight a role for folate metabolism and purine sensing in stem cell fate decisions and leukaemogenesis.
    DOI:  https://doi.org/10.1038/s41467-024-46114-0
  20. Cell Metab. 2024 Mar 01. pii: S1550-4131(24)00057-3. [Epub ahead of print]
    Aging-induced tRNAGlu-derived fragment impairs glutamate biosynthesis by targeting mitochondrial translation-dependent cristae organization.
    Dingfeng Li, Xinyi Gao, Xiaolin Ma, Ming Wang, Chuandong Cheng, Tian Xue, Feng Gao, Yong Shen, Juan Zhang, Qiang Liu.
      Mitochondrial cristae, infoldings of the mitochondrial inner membrane, undergo aberrant changes in their architecture with age. However, the underlying molecular mechanisms and their contribution to brain aging are largely elusive. Here, we observe an age-dependent accumulation of Glu-5'tsRNA-CTC, a transfer-RNA-derived small RNA (tsRNA), derived from nuclear-encoded tRNAGlu in the mitochondria of glutaminergic neurons. Mitochondrial Glu-5'tsRNA-CTC disrupts the binding of mt-tRNALeu and leucyl-tRNA synthetase2 (LaRs2), impairing mt-tRNALeu aminoacylation and mitochondria-encoded protein translation. Mitochondrial translation defects disrupt cristae organization, leading to damaged glutaminase (GLS)-dependent glutamate formation and reduced synaptosomal glutamate levels. Moreover, reduction of Glu-5'tsRNA-CTC protects aged brains from age-related defects in mitochondrial cristae organization, glutamate metabolism, synaptic structures, and memory. Thus, beyond illustrating a physiological role for normal mitochondrial cristae ultrastructure in maintaining glutamate levels, our study defines a pathological role for tsRNAs in brain aging and age-related memory decline.
    Keywords:  angiogenin; brain aging; cristae organization; glutamate metabolism; memory decline; mitochondria; mitochondrial translation; tRNA-derived small RNAs
    DOI:  https://doi.org/10.1016/j.cmet.2024.02.011
  21. Brain. 2024 Mar 04. pii: awae070. [Epub ahead of print]
    The lysosomal β-glucocerebrosidase strikes mitochondria: implications for Parkinson's therapeutics.
    Juan Carlos Rubilar, Tiago Fleming Outeiro, Andrés D Klein.
      Parkinson's disease (PD) is a neurodegenerative disorder primarily known for typical motor features that arise due to the loss of dopaminergic neurons in the substantia nigra. However, the precise molecular etiology of the disease is still unclear. Several cellular pathways have been linked to PD, including the autophagy-lysosome pathway (ALP), α-synuclein (α-syn) aggregation, and mitochondrial function. Interestingly, the mechanistic link between GBA1, the gene that encodes for lysosomal β-glucocerebrosidase (GCase), and PD lies in the interplay between GCase functions in the lysosome and mitochondria. GCase mutations alter mitochondria-lysosome contact sites. In the lysosome, reduced GCase activity leads to glycosphingolipid buildup, disrupting lysosomal function and autophagy, thereby triggering α-syn accumulation. Additionally, α-syn aggregates reduce GCase activity, creating a self-perpetuating cycle of lysosomal dysfunction and α-syn accumulation. GCase can also be imported into the mitochondria, where it promotes the integrity and function of mitochondrial complex I. Thus, GCase mutations that impair its normal function increase oxidative stress in mitochondria, the compartment where dopamine is oxidized. In turn, the accumulation of oxidized dopamine-adducts further impairs GCase activity, creating a second cycle of GCase dysfunction. The oxidative state triggered by GCase dysfunction can also induce mitochondrial DNA damage which, in turn, can cause dopaminergic cell death. In this review, we highlight the pivotal role of GCase in PD pathogenesis and discuss promising examples of GCase-based therapeutics such as gene and enzyme replacement therapies, small molecule chaperones, and substrate reduction therapies, among others, as potential therapeutic interventions.
    Keywords:  Gaucher’s disease; Parkinson’s disease; lysosome; mitochondria; neurodegeneration; therapeutics
    DOI:  https://doi.org/10.1093/brain/awae070
  22. Proc Natl Acad Sci U S A. 2024 Mar 12. 121(11): e2314199121
    Mechanism of proton-powered c-ring rotation in a mitochondrial ATP synthase.
    Florian E C Blanc, Gerhard Hummer.
      Proton-powered c-ring rotation in mitochondrial ATP synthase is crucial to convert the transmembrane protonmotive force into torque to drive the synthesis of adenosine triphosphate (ATP). Capitalizing on recent cryo-EM structures, we aim at a structural and energetic understanding of how functional directional rotation is achieved. We performed multi-microsecond atomistic simulations to determine the free energy profiles along the c-ring rotation angle before and after the arrival of a new proton. Our results reveal that rotation proceeds by dynamic sliding of the ring over the a-subunit surface, during which interactions with conserved polar residues stabilize distinct intermediates. Ordered water chains line up for a Grotthuss-type proton transfer in one of these intermediates. After proton transfer, a high barrier prevents backward rotation and an overall drop in free energy favors forward rotation, ensuring the directionality of c-ring rotation required for the thermodynamically disfavored ATP synthesis. The essential arginine of the a-subunit stabilizes the rotated configuration through a salt bridge with the c-ring. Overall, we describe a complete mechanism for the rotation step of the ATP synthase rotor, thereby illuminating a process critical to all life at atomic resolution.
    Keywords:  ATP synthase; bioenergetics; c-ring; molecular dynamics simulations; rotary motor
    DOI:  https://doi.org/10.1073/pnas.2314199121
  23. Nat Med. 2024 Mar 04.
    Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids.
    Mattia Francesco Maria Gerli, Giuseppe Calà, Max Arran Beesley, Beatrice Sina, Lucinda Tullie, Kylin Yunyan Sun, Francesco Panariello, Federica Michielin, Joseph R Davidson, Francesca Maria Russo, Brendan C Jones, Dani Do Hyang Lee, Savvas Savvidis, Theodoros Xenakis, Ian C Simcock, Anna A Straatman-Iwanowska, Robert A Hirst, Anna L David, Christopher O'Callaghan, Alessandro Olivo, Simon Eaton, Stavros P Loukogeorgakis, Davide Cacchiarelli, Jan Deprest, Vivian S W Li, Giovanni Giuseppe Giobbe, Paolo De Coppi.
      Isolation of tissue-specific fetal stem cells and derivation of primary organoids is limited to samples obtained from termination of pregnancies, hampering prenatal investigation of fetal development and congenital diseases. Therefore, new patient-specific in vitro models are needed. To this aim, isolation and expansion of fetal stem cells during pregnancy, without the need for tissue samples or reprogramming, would be advantageous. Amniotic fluid (AF) is a source of cells from multiple developing organs. Using single-cell analysis, we characterized the cellular identities present in human AF. We identified and isolated viable epithelial stem/progenitor cells of fetal gastrointestinal, renal and pulmonary origin. Upon culture, these cells formed clonal epithelial organoids, manifesting small intestine, kidney tubule and lung identity. AF organoids exhibit transcriptomic, protein expression and functional features of their tissue of origin. With relevance for prenatal disease modeling, we derived lung organoids from AF and tracheal fluid cells of congenital diaphragmatic hernia fetuses, recapitulating some features of the disease. AF organoids are derived in a timeline compatible with prenatal intervention, potentially allowing investigation of therapeutic tools and regenerative medicine strategies personalized to the fetus at clinically relevant developmental stages.
    DOI:  https://doi.org/10.1038/s41591-024-02807-z
  24. Geroscience. 2024 Mar 08.
    Mitochondrial disorders leading to Alzheimer's disease-perspectives of diagnosis and treatment.
    Magdalena Pszczołowska, Kamil Walczak, Weronika Miśków, Magdalena Mroziak, Justyna Chojdak-Łukasiewicz, Jerzy Leszek.
      Alzheimer's disease (AD) is a neurodegenerative disorder and the most common cause of dementia globally. The pathogenesis of AD remains still unclear. The three main features of AD are extracellular deposits of amyloid beta (Aβ) plaque, accumulation of abnormal formation hyper-phosphorylated tau protein, and neuronal loss. Mitochondrial impairment plays an important role in the pathogenesis of AD. There are problems with decreased activity of multiple complexes, disturbed mitochondrial fusion, and fission or formation of reactive oxygen species (ROS). Moreover, mitochondrial transport is impaired in AD. Mouse models in many research show disruptions in anterograde and retrograde transport. Both mitochondrial transportation and network impairment have a huge impact on synapse loss and, as a result, cognitive impairment. One of the very serious problems in AD is also disruption of insulin signaling which impairs mitochondrial Aβ removal.Discovering precise mechanisms leading to AD enables us to find new treatment possibilities. Recent studies indicate the positive influence of metformin or antioxidants such as MitoQ, SS-31, SkQ, MitoApo, MitoTEMPO, and MitoVitE on mitochondrial functioning and hence prevent cognitive decline. Impairments in mitochondrial fission may be treated with mitochondrial division inhibitor-1 or ceramide.
    Keywords:  Alzheimer’s disease; Antioxidants; MitoQ; Mitochondrial dysfunction; Oxidative stress; ROS
    DOI:  https://doi.org/10.1007/s11357-024-01118-y
  25. Nat Commun. 2024 Mar 04. 15(1): 1955
    A humanized mouse model for adeno-associated viral gene therapy.
    Mercedes Barzi, Tong Chen, Trevor J Gonzalez, Francis P Pankowicz, Seh Hoon Oh, Helen L Streff, Alan Rosales, Yunhan Ma, Sabrina Collias, Sarah E Woodfield, Anna Mae Diehl, Sanjeev A Vasudevan, Thao N Galvan, John Goss, Charles A Gersbach, Beatrice Bissig-Choisat, Aravind Asokan, Karl-Dimiter Bissig.
      Clinical translation of AAV-mediated gene therapy requires preclinical development across different experimental models, often confounded by variable transduction efficiency. Here, we describe a human liver chimeric transgene-free Il2rg-/-/Rag2-/-/Fah-/-/Aavr-/- (TIRFA) mouse model overcoming this translational roadblock, by combining liver humanization with AAV receptor (AAVR) ablation, rendering murine cells impermissive to AAV transduction. Using human liver chimeric TIRFA mice, we demonstrate increased transduction of clinically used AAV serotypes in primary human hepatocytes compared to humanized mice with wild-type AAVR. Further, we demonstrate AAV transduction in human teratoma-derived primary cells and liver cancer tissue, displaying the versatility of the humanized TIRFA mouse. From a mechanistic perspective, our results support the notion that AAVR functions as both an entry receptor and an intracellular receptor essential for transduction. The TIRFA mouse should allow prediction of AAV gene transfer efficiency and the study of AAV vector biology in a preclinical human setting.
    DOI:  https://doi.org/10.1038/s41467-024-46017-0
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