scholarly journals Expanding the Toolkit for In Vivo Imaging of Axonal Transport

10.3791/63471 ◽  
2021 ◽  
Author(s):  
Andrew P. Tosolini ◽  
David Villarroel-Campos ◽  
Giampietro Schiavo ◽  
James N. Sleigh
Keyword(s):  
Axonal Transport

scholarly journals C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility

2021 ◽  
Vol 7 (15) ◽  
pp. eabg3013
Author(s):  
Laura Fumagalli ◽  
Florence L. Young ◽  
Steven Boeynaems ◽  
Mathias De Decker ◽  
Arpan R. Mehta ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Motor Neurons ◽  
Single Molecule ◽  
Repeat Expansion ◽  
Physical Interaction ◽  
Hexanucleotide Repeat ◽  
Hexanucleotide Repeat Expansion ◽  
Axonal Trafficking ◽  
Inhibitory Interactions

A hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How this mutation leads to these neurodegenerative diseases remains unclear. Here, we show using patient stem cell–derived motor neurons that the repeat expansion impairs microtubule-based transport, a process critical for neuronal survival. Cargo transport defects are recapitulated by treating neurons from healthy individuals with proline-arginine and glycine-arginine dipeptide repeats (DPRs) produced from the repeat expansion. Both arginine-rich DPRs similarly inhibit axonal trafficking in adult Drosophila neurons in vivo. Physical interaction studies demonstrate that arginine-rich DPRs associate with motor complexes and the unstructured tubulin tails of microtubules. Single-molecule imaging reveals that microtubule-bound arginine-rich DPRs directly impede translocation of purified dynein and kinesin-1 motor complexes. Collectively, our study implicates inhibitory interactions of arginine-rich DPRs with axonal transport machinery in C9orf72-associated ALS/FTD and thereby points to potential therapeutic strategies.

Continuation of fast axonal transport in regenerating axons in vitro

1979 ◽  
Vol 57 (11) ◽  
pp. 1251-1255
Author(s):  
M. A. Bisby ◽  
C. E. Hilton
Keyword(s):  
Sciatic Nerve ◽  
Vagus Nerve ◽  
Axonal Transport ◽  
Nerve Injury ◽  
Axon Regeneration ◽  
Free Medium ◽  
Fast Axonal Transport ◽  
Sensory Axons

A previous study by McLean and co-workers reported that regenerating axons of the rabbit vagus nerve were unable to sustain axonal transport in vitro for several months after nerve injury. In contrast, we found that sensory axons of the rat sciatic nerve were able to transport 3H-labeled protein into their regenerating portions distal to the site of injury within a week after injury when placed in vitro. Transport in vitro was not significantly less than transport in axons maintained in vivo for the same period. Transport occurred in the medium that was used by the McLean group, but was significantly reduced in calcium-free medium. When axon regeneration was delared, only small amounts of activity were present in the nerve distal to the site of injury, showing that labeled protein normally present in that part of the nerve was associated with axons and was not a result of local precursor uptake by nonneural elements in the sciatic nerve. We were not able to explain the failure of McLean and co-workers to demonstrate transport in vitro in regenerating vagus nerve, but we conclude that there is no general peculiarity of growing axons that makes them unable to sustain transport in vitro.

scholarly journals C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility

2019 ◽  
Author(s):  
Laura Fumagalli ◽  
Florence L. Young ◽  
Steven Boeynaems ◽  
Mathias De Decker ◽  
Arpan R. Mehta ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Motor Neurons ◽  
Single Molecule ◽  
Induced Pluripotent Stem Cell ◽  
Cytoplasmic Dynein ◽  
Inhibitory Interaction ◽  
Hexanucleotide Repeat ◽  
Repeat Expansions

ABSTRACTHexanucleotide repeat expansions in the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How this mutation leads to these neurodegenerative diseases remains unclear. Here, we use human induced pluripotent stem cell-derived motor neurons to show that C9orf72 repeat expansions impair microtubule-based transport of mitochondria, a process critical for maintenance of neuronal function. Cargo transport defects are recapitulated by treating healthy neurons with the arginine-rich dipeptide repeat proteins (DPRs) that are produced by the hexanucleotide repeat expansions. Single-molecule imaging shows that these DPRs perturb motility of purified kinesin-1 and cytoplasmic dynein-1 motors along microtubules in vitro. Additional in vitro and in vivo data indicate that the DPRs impair transport by interacting with both microtubules and the motor complexes. We also show that kinesin-1 is enriched in DPR inclusions in patient brains and that increasing the level of this motor strongly suppresses the toxic effects of arginine-rich DPR expression in a Drosophila model. Collectively, our study implicates an inhibitory interaction of arginine-rich DPRs with the axonal transport machinery in C9orf72-associated ALS/FTD and thereby points to novel potential therapeutic strategies.

scholarly journals βII-spectrin promotes mouse brain connectivity through stabilizing axonal plasma membranes and enabling axonal organelle transport

2019 ◽  
Vol 116 (31) ◽  
pp. 15686-15695 ◽  
Author(s):  
Damaris N. Lorenzo ◽  
Alexandra Badea ◽  
Ruobo Zhou ◽  
Peter J. Mohler ◽  
Xiaowei Zhuang ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Plasma Membranes ◽  
Brain Connectivity ◽  
Axon Growth ◽  
Membrane Skeleton ◽  
Lipid Binding ◽  
Organelle Transport ◽  
Double Knockout ◽  
Micrometer Scale

βII-spectrin is the generally expressed member of the β-spectrin family of elongated polypeptides that form micrometer-scale networks associated with plasma membranes. We addressed in vivo functions of βII-spectrin in neurons by knockout of βII-spectrin in mouse neural progenitors. βII-spectrin deficiency caused severe defects in long-range axonal connectivity and axonal degeneration. βII-spectrin–null neurons exhibited reduced axon growth, loss of actin–spectrin-based periodic membrane skeleton, and impaired bidirectional axonal transport of synaptic cargo. We found that βII-spectrin associates with KIF3A, KIF5B, KIF1A, and dynactin, implicating spectrin in the coupling of motors and synaptic cargo. βII-spectrin required phosphoinositide lipid binding to promote axonal transport and restore axon growth. Knockout of ankyrin-B (AnkB), a βII-spectrin partner, primarily impaired retrograde organelle transport, while double knockout of βII-spectrin and AnkB nearly eliminated transport. Thus, βII-spectrin promotes both axon growth and axon stability through establishing the actin–spectrin-based membrane-associated periodic skeleton as well as enabling axonal transport of synaptic cargo.

scholarly journals ATAT1-enriched vesicles promote microtubule acetylation via axonal transport

2019 ◽  
Vol 5 (12) ◽  
pp. eaax2705 ◽  
Author(s):  
Aviel Even ◽  
Giovanni Morelli ◽  
Loïc Broix ◽  
Chiara Scaramuzzino ◽  
Silvia Turchetto ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Vesicular Transport ◽  
Microtubule Dynamics ◽  
Tubulin Acetylation ◽  
Cytosolic Side ◽  
Neuronal Vesicles ◽  
Β Tubulin

Microtubules are polymerized dimers of α- and β-tubulin that underlie a broad range of cellular activities. Acetylation of α-tubulin by the acetyltransferase ATAT1 modulates microtubule dynamics and functions in neurons. However, it remains unclear how this enzyme acetylates microtubules over long distances in axons. Here, we show that loss of ATAT1 impairs axonal transport in neurons in vivo, and cell-free motility assays confirm a requirement of α-tubulin acetylation for proper bidirectional vesicular transport. Moreover, we demonstrate that the main cellular pool of ATAT1 is transported at the cytosolic side of neuronal vesicles that are moving along axons. Together, our data suggest that axonal transport of ATAT1-enriched vesicles is the predominant driver of α-tubulin acetylation in axons.

scholarly journals Increased Human Wildtype Tau Attenuates Axonal Transport Deficits Caused by Loss of App in Mouse Models

2010 ◽  
Vol 4 ◽  
pp. MRI.S5237 ◽  
Author(s):  
Karen D.B. Smith ◽  
Erica Peethumnongsin ◽  
Han Lin ◽  
Hui Zheng ◽  
Robia G. Pautler
Keyword(s):  
Synaptic Plasticity ◽  
Axonal Transport ◽  
Mouse Models ◽  
Knockout Mice ◽  
Early Age ◽  
Axonal Elongation ◽  
Protein Tau ◽  
Manganese Enhanced Mri

Amyloid precursor protein (APP) is implicated in axonal elongation, synaptic plasticity, and axonal transport. However, the role of APP on axonal transport in conjunction with the microtubule associated protein tau continues to be debated. Here we measured in vivo axonal transport in APP knockout mice with Manganese Enhanced MRI (MEMRI) to determine whether APP is necessary for maintaining normal axonal transport. We also tested how overexpression and mutations of tau affect axonal transport in the presence or absence of APP. In vivo axonal transport reduced significantly in the absence of functional APP. Overexpression of human wildtype tau maintained normal axonal transport and resulted in a transient compensation of axonal transport deficits in the absence of APP. Mutant R406Wtau in combination with the absence of APP compounded axonal transport deficits and these deficits persisted with age. These results indicate that APP is necessary for axonal transport, and overexpression of human wildtype tau can compensate for the absence of APP at an early age.

scholarly journals In vivo axonal transport rates decrease in a mouse model of Alzheimer's disease

NeuroImage ◽  
2007 ◽  
Vol 35 (4) ◽  
pp. 1401-1408 ◽  
Author(s):  
Karen Dell Brown Smith ◽  
Verena Kallhoff ◽  
Hui Zheng ◽  
Robia G. Pautler
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Axonal Transport ◽  
Model Of Alzheimer’S Disease

scholarly journals The Carboxyl Terminus of Tegument Protein pUL21 Contributes to Pseudorabies Virus Neuroinvasion

2019 ◽  
Vol 93 (7) ◽  
Author(s):  
Kai Yan ◽  
Jie Liu ◽  
Xiang Guan ◽  
Yi-Xin Yin ◽  
Hui Peng ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Pseudorabies Virus ◽  
Motor Proteins ◽  
Retrograde Transport ◽  
Cytoplasmic Dynein ◽  
Bimolecular Fluorescence Complementation ◽  
Tegument Protein ◽  
Carboxyl Terminus ◽  
Anterograde Axonal Transport

ABSTRACTFollowing its entry into cells, pseudorabies virus (PRV) utilizes microtubules to deliver its nucleocapsid to the nucleus. Previous studies have shown that PRV VP1/2 is an effector of dynein-mediated capsid transport. However, the mechanism of PRV for recruiting microtubule motor proteins for successful neuroinvasion and neurovirulence is not well understood. Here, we provide evidence that PRV pUL21 is an inner tegument protein. We tested its interaction with the cytoplasmic light chains using a bimolecular fluorescence complementation (BiFC) assay and observed that PRV pUL21 interacts with Roadblock-1. This interaction was confirmed by coimmunoprecipitation (co-IP) assays. We also determined the efficiency of retrograde and anterograde axonal transport of PRV strains in explanted neurons using a microfluidic chamber system and investigated pUL21’s contribution to PRV neuroinvasionin vivo. Further data showed that the carboxyl terminus of pUL21 is essential for its interaction with Roadblock-1, and this domain contributes to PRV retrograde axonal transportin vitroandin vivo. Our findings suggest that the carboxyl terminus of pUL21 contributes to PRV neuroinvasion.IMPORTANCEHerpesviruses are a group of DNA viruses that infect both humans and animals. Alphaherpesviruses are distinguished by their ability to establish latent infection in peripheral neurons. After entering neurons, the herpesvirus capsid interacts with cellular motor proteins and undergoes retrograde transport on axon microtubules. This elaborate process is vital to the herpesvirus lifecycle, but the underlying mechanism remains poorly understood. Here, we determined that pUL21 is an inner tegument protein of pseudorabies virus (PRV) and that it interacts with the cytoplasmic dynein light chain Roadblock-1. We also observed that pUL21 promotes retrograde transport of PRV in neuronal cells. Furthermore, our findings confirm that pUL21 contributes to PRV neuroinvasionin vivo. Importantly, the carboxyl terminus of pUL21 is responsible for interaction with Roadblock-1, and this domain contributes to PRV neuroinvasion. This study offers fresh insights into alphaherpesvirus neuroinvasion and the interaction between virus and host during PRV infection.

scholarly journals Smcr8 deficiency disrupts axonal transport-dependent lysosomal function and promotes axonal swellings and gain of toxicity in C9ALS/FTD mouse models

2019 ◽  
Vol 28 (23) ◽  
pp. 3940-3953 ◽  
Author(s):  
Chen Liang ◽  
Qiang Shao ◽  
Wei Zhang ◽  
Mei Yang ◽  
Qing Chang ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Mouse Models ◽  
Motor Neurons ◽  
Neuromuscular Junctions ◽  
Motor Behavior ◽  
In Vivo Studies ◽  
Lysosomal Function ◽  
Repeat Expansions ◽  
Axonal Swellings

Abstract G4C2 repeat expansions in an intron of C9ORF72 cause the most common familial amyotrophic lateral sclerosis and frontotemporal dementia (collectively, C9ALS/FTD). Mechanisms and mediators of C9ALS/FTD pathogenesis remain poorly understood. C9orf72 and Smcr8 form a protein complex. Here, we show that expression of Smcr8, like C9orf72, is reduced in C9ALS/FTD mouse models and patient tissues. Since Smcr8 is highly conserved between human and mouse, we evaluated the effects of Smcr8 downregulation in mice. Smcr8 knockout (KO) mice exhibited motor behavior deficits, which resemble those of C9ALS/FTD mouse models, and displayed axonal swellings in their spinal cords and neuromuscular junctions. These deficits are caused by impaired autophagy-lysosomal functions due to disrupted axonal transport in mutant motor neurons. Consistent with its interaction with C9orf72 and their downregulation in patient tissues, Smcr8 deficiency exacerbated autophagy-lysosomal impairment in C9orf72 KO mice. The disease relevance of Smcr8 downregulation was reflected by exacerbated axonal swellings and gain of toxicity pathology arising from Smcr8 haploinsufficiency in a mouse model of C9ALS/FTD. Thus, our in vivo studies suggested that Smcr8 deficiency impairs axonal transport dependent autophagy-lysosomal function and exacerbates axonal degeneration and gain of toxicity in C9ALS/FTD mouse models.

scholarly journals Vesicular Axonal Transport is Modified In Vivo by Tau Deletion or Overexpression in Drosophila

2018 ◽  
Vol 19 (3) ◽  
pp. 744 ◽  
Author(s):  
Yasmina Talmat-Amar ◽  
Yoan Arribat ◽  
Marie-Laure Parmentier
Keyword(s):  
Axonal Transport
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