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Baranov MV, Kumar M, Sacanna S, Thutupalli S, van den Bogaart G. Modulation of Immune Responses by Particle Size and Shape. Front Immunol 2021; 11:607945. [PMID: 33679696 PMCID: PMC7927956 DOI: 10.3389/fimmu.2020.607945] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/23/2020] [Indexed: 12/12/2022] Open
Abstract
The immune system has to cope with a wide range of irregularly shaped pathogens that can actively move (e.g., by flagella) and also dynamically remodel their shape (e.g., transition from yeast-shaped to hyphal fungi). The goal of this review is to draw general conclusions of how the size and geometry of a pathogen affect its uptake and processing by phagocytes of the immune system. We compared both theoretical and experimental studies with different cells, model particles, and pathogenic microbes (particularly fungi) showing that particle size, shape, rigidity, and surface roughness are important parameters for cellular uptake and subsequent immune responses, particularly inflammasome activation and T cell activation. Understanding how the physical properties of particles affect immune responses can aid the design of better vaccines.
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Affiliation(s)
- Maksim V. Baranov
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Manoj Kumar
- Simons Center for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Stefano Sacanna
- Molecular Design Institute, Department of Chemistry, New York University, New York, NY, United States
| | - Shashi Thutupalli
- Simons Center for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
- International Centre for Theoretical Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Geert van den Bogaart
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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Chen F, Amgalan D, Kitsis RN, Pessin JE, Feng D. ATG16L1 autophagy pathway regulates BAX protein levels and programmed cell death. J Biol Chem 2020; 295:15045-15053. [PMID: 32848017 PMCID: PMC7606669 DOI: 10.1074/jbc.ra120.013999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/20/2020] [Indexed: 01/05/2023] Open
Abstract
Previously we reported that adipocyte SNAP23 (synaptosome-associated protein of 23 kDa) deficiency blocks the activation of macroautophagy, leading to an increased abundance of BAX, a pro-death Bcl-2 family member, and activation and adipocyte cell death both in vitro and in vivo Here, we found that knockdown of SNAP23 inhibited the association of the autophagosome regulators ATG16L1 and ATG9 compartments by nutrient depletion and reduced the formation of ATG16L1 membrane puncta. ATG16L1 knockdown inhibited autophagy flux and increased BAX protein levels by suppressing BAX degradation. The elevation in BAX protein had no effect on BAX activation or cell death in the nutrient-replete state. However, following nutrient depletion, BAX was activated with a concomitant induction of cell death. Co-immunoprecipitation analyses demonstrated that SNAP23 and ATG16L1 proteins form a stable complex independent of nutrient condition, whereas in the nutrient-depleted state, BAX binds to SNAP23 to form a ternary BAX-SNAP23-ATG16L1 protein complex. Taken together, these data support a model in which SNAP23 plays a crucial function as a scaffold for ATG16L1 necessary for the suppression of BAX activation and induction of the intrinsic cell death program.
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Affiliation(s)
- Fenfen Chen
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Dulguun Amgalan
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Richard N. Kitsis
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA,Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jeffrey E. Pessin
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA,Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Wilf Family Cardiovascular Research Center, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Daorong Feng
- Fleischer Institute of Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA,For correspondence: Daorong Feng,
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Moya-Alvarado G, Gonzalez A, Stuardo N, Bronfman FC. Brain-Derived Neurotrophic Factor (BDNF) Regulates Rab5-Positive Early Endosomes in Hippocampal Neurons to Induce Dendritic Branching. Front Cell Neurosci 2018; 12:493. [PMID: 30618640 PMCID: PMC6304382 DOI: 10.3389/fncel.2018.00493] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 11/30/2018] [Indexed: 11/24/2022] Open
Abstract
Neurotrophin receptors use endosomal pathways for signaling in neurons. However, how neurotrophins regulate the endosomal system for proper signaling is unknown. Rabs are monomeric GTPases that act as molecular switches to regulate membrane trafficking by binding a wide range of effectors. Among the Rab GTPases, Rab5 is the key GTPase regulating early endosomes and is the first sorting organelle of endocytosed receptors. The objective of our work was to study the regulation of Rab5-positive endosomes by BDNF at different levels, including dynamic, activity and protein levels in hippocampal neurons. Short-term treatment with BDNF increased the colocalization of TrkB in dendrites and cell bodies, increasing the vesiculation of Rab5-positive endosomes. Consistently, BDNF increased the number and mobility of Rab5 endosomes in dendrites. Cell body fluorescence recovery after photobleaching of Rab-EGFP-expressing neurons suggested increased movement of Rab5 endosomes from dendrites to cell bodies. These results correlated with the BDNF-induced activation of Rab5 in dendrites, followed by increased activation of Rab5 in cell bodies. Long-term treatment of hippocampal neurons with BDNF increased the protein levels of Rab5 and Rab11 in an mTOR-dependent manner. While BDNF regulation of Rab5a levels occurred at both the transcriptional and translational levels, Rab11a levels were regulated at the translational level at the time points analyzed. Finally, expression of a dominant-negative mutant of Rab5 reduced the basal arborization of nontreated neurons, and although BDNF was partially able to rescue the effect of Rab5DN at the level of primary dendrites, BDNF-induced dendritic branching was largely reduced. Our findings indicate that BDNF regulates the Rab5-Rab11 endosomal system at different levels and that these processes are likely required for BDNF-induced dendritic branching.
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Affiliation(s)
- Guillermo Moya-Alvarado
- Department of Physiology, Faculty of Biological Sciences, Center for Aging and Regeneration (CARE UC), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andres Gonzalez
- Department of Physiology, Faculty of Biological Sciences, Center for Aging and Regeneration (CARE UC), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolas Stuardo
- Department of Physiology, Faculty of Biological Sciences, Center for Aging and Regeneration (CARE UC), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisca C Bronfman
- Department of Physiology, Faculty of Biological Sciences, Center for Aging and Regeneration (CARE UC), Pontificia Universidad Católica de Chile, Santiago, Chile
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