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Wisner SR, Chlebowski M, Mandal A, Mai D, Stein C, Petralia RS, Wang YX, Drerup CM. An initial HOPS-mediated fusion event is critical for autophagosome transport initiation from the axon terminal. Autophagy 2024:1-22. [PMID: 38899385 DOI: 10.1080/15548627.2024.2366122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 06/05/2024] [Indexed: 06/21/2024] Open
Abstract
In neurons, macroautophagy/autophagy is a frequent and critical process. In the axon, autophagy begins in the axon terminal, where most nascent autophagosomes form. After formation, autophagosomes must initiate transport to exit the axon terminal and move toward the cell body via retrograde transport. During retrograde transport these autophagosomes mature through repetitive fusion events. Complete lysosomal cargo degradation occurs largely in the cell body. The precipitating events to stimulate retrograde autophagosome transport have been debated but their importance is clear: disrupting neuronal autophagy or autophagosome transport is detrimental to neuronal health and function. We have identified the HOPS complex as essential for early autophagosome maturation and consequent initiation of retrograde transport from the axon terminal. In yeast and mammalian cells, HOPS controls fusion between autophagosomes and late endosomes with lysosomes. Using zebrafish strains with loss-of-function mutations in vps18 and vps41, core components of the HOPS complex, we found that disruption of HOPS eliminates autophagosome maturation and disrupts retrograde autophagosome transport initiation from the axon terminal. We confirmed this phenotype was due to loss of HOPS complex formation using an endogenous deletion of the HOPS binding domain in Vps18. Finally, using pharmacological inhibition of lysosomal proteases, we show that initiation of autophagosome retrograde transport requires autophagosome maturation. Together, our data demonstrate that HOPS-mediated fusion events are critical for retrograde autophagosome transport initiation through promoting autophagosome maturation. This reveals critical roles for the HOPS complex in neuronal autophagy which deepens our understanding of the cellular pathology of HOPS-complex linked neurodegenerative diseases.Abbreviations: CORVET: Class C core vacuole/endosome tethering; gRNA: guide RNA; HOPS: homotypic fusion and protein sorting; pLL: posterior lateral line; Vps18: VPS18 core subunit of CORVET and HOPS complexes; Vps41: VPS41 subunit of HOPS complex.
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Affiliation(s)
- Serena R Wisner
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Madison Chlebowski
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Amrita Mandal
- National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Don Mai
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris Stein
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute of Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute of Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Catherine M Drerup
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
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2
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Donovan EJ, Agrawal A, Liberman N, Kalai JI, Adler AJ, Lamper AM, Wang HQ, Chua NJ, Koslover EF, Barnhart EL. Dendrite architecture determines mitochondrial distribution patterns in vivo. Cell Rep 2024; 43:114190. [PMID: 38717903 DOI: 10.1016/j.celrep.2024.114190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/08/2024] [Accepted: 04/17/2024] [Indexed: 06/01/2024] Open
Abstract
Neuronal morphology influences synaptic connectivity and neuronal signal processing. However, it remains unclear how neuronal shape affects steady-state distributions of organelles like mitochondria. In this work, we investigated the link between mitochondrial transport and dendrite branching patterns by combining mathematical modeling with in vivo measurements of dendrite architecture, mitochondrial motility, and mitochondrial localization patterns in Drosophila HS (horizontal system) neurons. In our model, different forms of morphological and transport scaling rules-which set the relative thicknesses of parent and daughter branches at each junction in the dendritic arbor and link mitochondrial motility to branch thickness-predict dramatically different global mitochondrial localization patterns. We show that HS dendrites obey the specific subset of scaling rules that, in our model, lead to realistic mitochondrial distributions. Moreover, we demonstrate that neuronal activity does not affect mitochondrial transport or localization, indicating that steady-state mitochondrial distributions are hard-wired by the architecture of the neuron.
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Affiliation(s)
- Eavan J Donovan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Anamika Agrawal
- Department of Physics, University of California, San Diego, La Jolla, CA 92092, USA
| | - Nicole Liberman
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jordan I Kalai
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Avi J Adler
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Adam M Lamper
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Hailey Q Wang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Nicholas J Chua
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Elena F Koslover
- Department of Physics, University of California, San Diego, La Jolla, CA 92092, USA
| | - Erin L Barnhart
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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Koehler S, Hengel FE, Dumoulin B, Damashek L, Holzman LB, Susztak K, Huber TB. The 14th International Podocyte Conference 2023: from podocyte biology to glomerular medicine. Kidney Int 2024; 105:935-952. [PMID: 38447880 DOI: 10.1016/j.kint.2024.01.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/11/2023] [Accepted: 01/02/2024] [Indexed: 03/08/2024]
Abstract
The 14th International Podocyte Conference took place in Philadelphia, Pennsylvania, USA from May 23 to 26, 2023. It commenced with an early-career researchers' meeting on May 23, providing young scientists with a platform to present and discuss their research findings. Throughout the main conference, 29 speakers across 9 sessions shared their insights on podocyte biology, glomerular medicine, novel technologic advancements, and translational approaches. Additionally, the event featured 3 keynote lectures addressing engineered chimeric antigen receptor T cell- and mRNA-based therapies and the use of biobanks for enhanced disease comprehension. Furthermore, 4 brief oral abstract sessions allowed scientists to present their findings to a broad audience. The program also included a panel discussion addressing the challenges of conducting human research within the American Black community. Remarkably, after a 5-year hiatus from in-person conferences, the 14th International Podocyte Conference successfully convened scientists from around the globe, fostering the presentation and discussion of crucial research findings, as summarized in this review. Furthermore, to ensure continuous and sustainable education, research, translation, and trial medicine related to podocyte and glomerular diseases for the benefit of patients, the International Society of Glomerular Disease was officially launched during the conference.
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Affiliation(s)
- Sybille Koehler
- III. Department of Medicine and Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Felicitas E Hengel
- III. Department of Medicine and Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Bernhard Dumoulin
- III. Department of Medicine and Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; Renal, Electrolyte, and Hypertension Division, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Laurel Damashek
- International Society of Glomerular Disease, Florence, Massachusetts, USA
| | - Lawrence B Holzman
- Renal, Electrolyte, and Hypertension Division, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Katalin Susztak
- Renal, Electrolyte, and Hypertension Division, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Institute of Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tobias B Huber
- III. Department of Medicine and Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; International Society of Glomerular Disease, Florence, Massachusetts, USA.
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Bond C, Hugelier S, Xing J, Sorokina EM, Lakadamyali M. Multiplexed DNA-PAINT Imaging of the Heterogeneity of Late Endosome/Lysosome Protein Composition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585634. [PMID: 38562776 PMCID: PMC10983937 DOI: 10.1101/2024.03.18.585634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Late endosomes/lysosomes (LELs) are crucial for numerous physiological processes and their dysfunction is linked to many diseases. Proteomic analyses have identified hundreds of LEL proteins, however, whether these proteins are uniformly present on each LEL, or if there are cell-type dependent LEL sub-populations with unique protein compositions is unclear. We employed a quantitative, multiplexed DNA-PAINT super-resolution approach to examine the distribution of six key LEL proteins (LAMP1, LAMP2, CD63, TMEM192, NPC1 and LAMTOR4) on individual LELs. While LAMP1 and LAMP2 were abundant across LELs, marking a common population, most analyzed proteins were associated with specific LEL subpopulations. Our multiplexed imaging approach identified up to eight different LEL subpopulations based on their unique membrane protein composition. Additionally, our analysis of the spatial relationships between these subpopulations and mitochondria revealed a cell-type specific tendency for NPC1-positive LELs to be closely positioned to mitochondria. Our approach will be broadly applicable to determining organelle heterogeneity with single organelle resolution in many biological contexts. Summary This study develops a multiplexed and quantitative DNA-PAINT super-resolution imaging pipeline to investigate the distribution of late endosomal/lysosomal (LEL) proteins across individual LELs, revealing cell-type specific LEL sub-populations with unique protein compositions, offering insights into organelle heterogeneity at single-organelle resolution.
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Nambiar A, Manjithaya R. Driving autophagy - the role of molecular motors. J Cell Sci 2024; 137:jcs260481. [PMID: 38329417 DOI: 10.1242/jcs.260481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024] Open
Abstract
Most of the vesicular transport pathways inside the cell are facilitated by molecular motors that move along cytoskeletal networks. Autophagy is a well-explored catabolic pathway that is initiated by the formation of an isolation membrane known as the phagophore, which expands to form a double-membraned structure that captures its cargo and eventually moves towards the lysosomes for fusion. Molecular motors and cytoskeletal elements have been suggested to participate at different stages of the process as the autophagic vesicles move along cytoskeletal tracks. Dynein and kinesins govern autophagosome trafficking on microtubules through the sequential recruitment of their effector proteins, post-translational modifications and interactions with LC3-interacting regions (LIRs). In contrast, myosins are actin-based motors that participate in various stages of the autophagic flux, as well as in selective autophagy pathways. However, several outstanding questions remain with regard to how the dominance of a particular motor protein over another is controlled, and to the molecular mechanisms that underlie specific disease variants in motor proteins. In this Review, we aim to provide an overview of the role of molecular motors in autophagic flux, as well as highlight their dysregulation in diseases, such as neurodegenerative disorders and pathogenic infections, and ageing.
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Affiliation(s)
- Akshaya Nambiar
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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Kim HR, Lee HJ, Jeon Y, Jang SY, Shin YK, Yun JH, Park HJ, Koh H, Lee KE, Shin JE, Park HT. Targeting SARM1 improves autophagic stress-induced axonal neuropathy. Autophagy 2024; 20:29-44. [PMID: 37561040 PMCID: PMC10761069 DOI: 10.1080/15548627.2023.2244861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/23/2023] [Accepted: 07/31/2023] [Indexed: 08/11/2023] Open
Abstract
ABBREVIATIONS AAV: adeno-associated virus; ATF3: activating transcription factor 3; ATG7: autophagy related 7; AVIL: advillin; cADPR: cyclic ADP ribose; CALC: calcitonin/calcitonin-related polypeptide; CMT: Charcot-Marie-Tooth disease; cKO: conditional knockout; DEG: differentially expressed gene; DRG: dorsal root ganglion; FE-SEM: field emission scanning electron microscopy; IF: immunofluorescence; NCV: nerve conduction velocity; PVALB: parvalbumin; RAG: regeneration-associated gene; ROS: reactive oxygen species; SARM1: sterile alpha and HEAT/Armadillo motif containing 1; SYN1: synapsin I.
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Affiliation(s)
- Hye Ran Kim
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hye Jin Lee
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Yewon Jeon
- Department of Life Sciences, Division of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - So Young Jang
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Yoon Kyoung Shin
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Jean Ho Yun
- Department of Biochemistry, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hye Ji Park
- Neuroscience Translational Research Solution Center, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hyongjong Koh
- Neuroscience Translational Research Solution Center, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Kyung Eun Lee
- Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Jung Eun Shin
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hwan Tae Park
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience and Translational Biomedical Sciences, Dong-A University College of Medicine, Busan, Republic of Korea
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Cason SE, Holzbaur EL. Axonal transport of autophagosomes is regulated by dynein activators JIP3/JIP4 and ARF/RAB GTPases. J Cell Biol 2023; 222:e202301084. [PMID: 37909920 PMCID: PMC10620608 DOI: 10.1083/jcb.202301084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 08/28/2023] [Accepted: 10/05/2023] [Indexed: 11/03/2023] Open
Abstract
Neuronal autophagosomes form and engulf cargos at presynaptic sites in the axon and are then transported to the soma to recycle their cargo. Autophagic vacuoles (AVs) mature en route via fusion with lysosomes to become degradatively competent organelles; transport is driven by the microtubule motor protein cytoplasmic dynein, with motor activity regulated by a sequential series of adaptors. Using lysate-based single-molecule motility assays and live-cell imaging in primary neurons, we show that JNK-interacting proteins 3 (JIP3) and 4 (JIP4) are activating adaptors for dynein that are regulated on autophagosomes and lysosomes by the small GTPases ARF6 and RAB10. GTP-bound ARF6 promotes formation of the JIP3/4-dynein-dynactin complex. Either knockdown or overexpression of RAB10 stalls transport, suggesting that this GTPase is also required to coordinate the opposing activities of bound dynein and kinesin motors. These findings highlight the complex coordination of motor regulation during organelle transport in neurons.
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Affiliation(s)
- Sydney E. Cason
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Erika L.F. Holzbaur
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
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8
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Dou D, Smith EM, Evans CS, Boecker CA, Holzbaur ELF. Regulatory imbalance between LRRK2 kinase, PPM1H phosphatase, and ARF6 GTPase disrupts the axonal transport of autophagosomes. Cell Rep 2023; 42:112448. [PMID: 37133994 PMCID: PMC10304398 DOI: 10.1016/j.celrep.2023.112448] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/15/2023] [Accepted: 04/13/2023] [Indexed: 05/04/2023] Open
Abstract
Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), increasing phosphorylation of RAB GTPases through hyperactive kinase activity. We find that LRRK2-hyperphosphorylated RABs disrupt the axonal transport of autophagosomes by perturbing the coordinated regulation of cytoplasmic dynein and kinesin. In iPSC-derived human neurons, knockin of the strongly hyperactive LRRK2-p.R1441H mutation causes striking impairments in autophagosome transport, inducing frequent directional reversals and pauses. Knockout of the opposing protein phosphatase 1H (PPM1H) phenocopies the effect of hyperactive LRRK2. Overexpression of ADP-ribosylation factor 6 (ARF6), a GTPase that acts as a switch for selective activation of dynein or kinesin, attenuates transport defects in both p.R1441H knockin and PPM1H knockout neurons. Together, these findings support a model where a regulatory imbalance between LRRK2-hyperphosphorylated RABs and ARF6 induces an unproductive "tug-of-war" between dynein and kinesin, disrupting processive autophagosome transport. This disruption may contribute to PD pathogenesis by impairing the essential homeostatic functions of axonal autophagy.
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Affiliation(s)
- Dan Dou
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA; Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Erin M Smith
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chantell S Evans
- Duke University Medical Center, Duke University, Durham, NC 27710, USA
| | - C Alexander Boecker
- Department of Neurology, University Medical Center Goettingen, 37077 Goettingen, Germany.
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA; Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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Cason SE, Holzbaur EL. Axonal transport of autophagosomes is regulated by dynein activators JIP3/JIP4 and ARF/RAB GTPases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.28.526044. [PMID: 36747648 PMCID: PMC9901177 DOI: 10.1101/2023.01.28.526044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Neuronal autophagosomes, "self-eating" degradative organelles, form at presynaptic sites in the distal axon and are transported to the soma to recycle their cargo. During transit, autophagic vacuoles (AVs) mature through fusion with lysosomes to acquire the enzymes necessary to breakdown their cargo. AV transport is driven primarily by the microtubule motor cytoplasmic dynein in concert with dynactin and a series of activating adaptors that change depending on organelle maturation state. The transport of mature AVs is regulated by the scaffolding proteins JIP3 and JIP4, both of which activate dynein motility in vitro. AV transport is also regulated by ARF6 in a GTP-dependent fashion. While GTP-bound ARF6 promotes the formation of the JIP3/4-dynein-dynactin complex, RAB10 competes with the activity of this complex by increasing kinesin recruitment to axonal AVs and lysosomes. These interactions highlight the complex coordination of motors regulating organelle transport in neurons.
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Affiliation(s)
- Sydney E. Cason
- Department of Physiology, University of Pennsylvania
- Neuroscience Graduate Group, University of Pennsylvania
- Pennsylvania Muscle Institute, University of Pennsylvania
| | - Erika L.F. Holzbaur
- Department of Physiology, University of Pennsylvania
- Neuroscience Graduate Group, University of Pennsylvania
- Pennsylvania Muscle Institute, University of Pennsylvania
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