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Vaquié A, Sauvain A, Duman M, Nocera G, Egger B, Meyenhofer F, Falquet L, Bartesaghi L, Chrast R, Lamy CM, Bang S, Lee SR, Jeon NL, Ruff S, Jacob C. Injured Axons Instruct Schwann Cells to Build Constricting Actin Spheres to Accelerate Axonal Disintegration. Cell Rep 2020; 27:3152-3166.e7. [PMID: 31189102 DOI: 10.1016/j.celrep.2019.05.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/11/2019] [Accepted: 05/17/2019] [Indexed: 01/26/2023] Open
Abstract
After a peripheral nerve lesion, distal ends of injured axons disintegrate into small fragments that are subsequently cleared by Schwann cells and later by macrophages. Axonal debris clearing is an early step of the repair process that facilitates regeneration. We show here that Schwann cells promote distal cut axon disintegration for timely clearing. By combining cell-based and in vivo models of nerve lesion with mouse genetics, we show that this mechanism is induced by distal cut axons, which signal to Schwann cells through PlGF mediating the activation and upregulation of VEGFR1 in Schwann cells. In turn, VEGFR1 activates Pak1, leading to the formation of constricting actomyosin spheres along unfragmented distal cut axons to mediate their disintegration. Interestingly, oligodendrocytes can acquire a similar behavior as Schwann cells by enforced expression of VEGFR1. These results thus identify controllable molecular cues of a neuron-glia crosstalk essential for timely clearing of damaged axons.
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Affiliation(s)
- Adrien Vaquié
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Alizée Sauvain
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Mert Duman
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gianluigi Nocera
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Bioimage Light Microscopy Facility, University of Fribourg, Fribourg, Switzerland
| | - Felix Meyenhofer
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Medicine, University of Fribourg, Fribourg, Switzerland; Bioimage Light Microscopy Facility, University of Fribourg, Fribourg, Switzerland
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Medicine, University of Fribourg, Fribourg, Switzerland; Bioinformatics Core Facility, University of Fribourg and Swiss Institute of Bioinformatics, Fribourg, Switzerland
| | - Luca Bartesaghi
- Departments of Neuroscience and Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Roman Chrast
- Departments of Neuroscience and Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Seokyoung Bang
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Seung-Ryeol Lee
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Noo Li Jeon
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea
| | - Sophie Ruff
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Claire Jacob
- Department of Biology, University of Fribourg, Fribourg, Switzerland; Department of Biology, Johannes Gutenberg University Mainz, Mainz, Germany.
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Grzegorzewicz AE, Korduláková J, Jones V, Born SEM, Belardinelli JM, Vaquié A, Gundi VAKB, Madacki J, Slama N, Laval F, Vaubourgeix J, Crew RM, Gicquel B, Daffé M, Morbidoni HR, Brennan PJ, Quémard A, McNeil MR, Jackson M. A common mechanism of inhibition of the Mycobacterium tuberculosis mycolic acid biosynthetic pathway by isoxyl and thiacetazone. J Biol Chem 2012; 287:38434-41. [PMID: 23002234 DOI: 10.1074/jbc.m112.400994] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Isoxyl (ISO) and thiacetazone (TAC), two prodrugs once used in the clinical treatment of tuberculosis, have long been thought to abolish Mycobacterium tuberculosis (M. tuberculosis) growth through the inhibition of mycolic acid biosynthesis, but their respective targets in this pathway have remained elusive. Here we show that treating M. tuberculosis with ISO or TAC results in both cases in the accumulation of 3-hydroxy C(18), C(20), and C(22) fatty acids, suggestive of an inhibition of the dehydratase step of the fatty-acid synthase type II elongation cycle. Consistently, overexpression of the essential hadABC genes encoding the (3R)-hydroxyacyl-acyl carrier protein dehydratases resulted in more than a 16- and 80-fold increase in the resistance of M. tuberculosis to ISO and TAC, respectively. A missense mutation in the hadA gene of spontaneous ISO- and TAC-resistant mutants was sufficient to confer upon M. tuberculosis high level resistance to both drugs. Other mutations found in hypersusceptible or resistant M. tuberculosis and Mycobacterium kansasii isolates mapped to hadC. Mutations affecting the non-essential mycolic acid methyltransferases MmaA4 and MmaA2 were also found in M. tuberculosis spontaneous ISO- and TAC-resistant mutants. That MmaA4, at least, participates in the activation of the two prodrugs as proposed earlier is not supported by our biochemical evidence. Instead and in light of the known interactions of both MmaA4 and MmaA2 with HadAB and HadBC, we propose that mutations affecting these enzymes may impact the binding of ISO and TAC to the dehydratases.
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Affiliation(s)
- Anna E Grzegorzewicz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, USA
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