Identification of a novel pathway for the in vivo regulation of fast anterograde axonal transport

2008 ◽  
Vol 81 ◽  
pp. 93-94
Author(s):  
Gerardo Morfini ◽  
G. Szebenyi ◽  
H. Brown ◽  
R. Wray ◽  
H. Reyna ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Anterograde Axonal Transport

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 α-Synuclein oligomers induce early axonal dysfunction in human iPSC-based models of synucleinopathies

2018 ◽  
Vol 115 (30) ◽  
pp. 7813-7818 ◽  
Author(s):  
Iryna Prots ◽  
Janina Grosch ◽  
Razvan-Marius Brazdis ◽  
Katrin Simmnacher ◽  
Vanesa Veber ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Disease Patient ◽  
In Vivo Models ◽  
Human Neurons ◽  
Anterograde Axonal Transport ◽  
Axonal Dysfunction ◽  
Underlying Mechanisms ◽  
Human Ipsc

α-Synuclein (α-Syn) aggregation, proceeding from oligomers to fibrils, is one central hallmark of neurodegeneration in synucleinopathies. α-Syn oligomers are toxic by triggering neurodegenerative processes in in vitro and in vivo models. However, the precise contribution of α-Syn oligomers to neurite pathology in human neurons and the underlying mechanisms remain unclear. Here, we demonstrate the formation of oligomeric α-Syn intermediates and reduced axonal mitochondrial transport in human neurons derived from induced pluripotent stem cells (iPSC) from a Parkinson’s disease patient carrying an α-Syn gene duplication. We further show that increased levels of α-Syn oligomers disrupt axonal integrity in human neurons. We apply an α-Syn oligomerization model by expressing α-Syn oligomer-forming mutants (E46K and E57K) and wild-type α-Syn in human iPSC-derived neurons. Pronounced α-Syn oligomerization led to impaired anterograde axonal transport of mitochondria, which can be restored by the inhibition of α-Syn oligomer formation. Furthermore, α-Syn oligomers were associated with a subcellular relocation of transport-regulating proteins Miro1, KLC1, and Tau as well as reduced ATP levels, underlying axonal transport deficits. Consequently, reduced axonal density and structural synaptic degeneration were observed in human neurons in the presence of high levels of α-Syn oligomers. Together, increased dosage of α-Syn resulting in α-Syn oligomerization causes axonal transport disruption and energy deficits, leading to synapse loss in human neurons. This study identifies α-Syn oligomers as the critical species triggering early axonal dysfunction in synucleinopathies.

scholarly journals Inhibition of LRRK2 kinase activity promotes anterograde axonal transport and presynaptic targeting of α-synuclein

2021 ◽  
Author(s):  
Charlotte F Brzozowski ◽  
Baraa A Hijaz ◽  
Vijay Singh ◽  
Nolwazi Z Gcwensa ◽  
Kaela Kelly ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Kinase Activity ◽  
Alpha Synuclein ◽  
Presynaptic Terminal ◽  
Lewy Pathology ◽  
Anterograde Axonal Transport ◽  
Lrrk2 Kinase ◽  
The Impact ◽  
Lrrk2 Kinase Activity

Pathologic inclusions composed of alpha-synuclein called Lewy pathology are hallmarks of Parkinson Disease (PD). Dominant inherited mutations in leucine rich repeat kinase 2 (LRRK2) are the most common genetic cause of PD. Lewy pathology is found in the majority of individuals with LRRK2-PD, particularly those with the G2019S-LRRK2 mutation. Lewy pathology in LRRK2-PD associates with increased non-motor symptoms such as cognitive deficits, anxiety, and orthostatic hypotension. Thus, understanding the relationship between LRRK2 and alpha-synuclein could be important for determining the mechanisms of non-motor symptoms. In PD models, expression of mutant LRRK2 reduces membrane localization of alpha-synuclein, and enhances formation of pathologic alpha-synuclein, particularly when synaptic activity is increased. alpha-Synuclein and LRRK2 both localize to the presynaptic terminal. LRRK2 plays a role in membrane traffic, including axonal transport, and therefore may influence alpha-synuclein synaptic localization. This study shows that LRRK2 kinase activity influences alpha-synuclein targeting to the presynaptic terminal. We used the selective LRRK2 kinase inhibitors, MLi-2 and PF-06685360 (PF-360) to determine the impact of reduced LRRK2 kinase activity on presynaptic localization of alpha-synuclein. Expansion microscopy (ExM) in primary hippocampal cultures and the mouse striatum, in vivo, was used to more precisely resolve the presynaptic localization of alpha-synuclein. Live imaging of axonal transport of alpha-synuclein-GFP was used to investigate the impact of LRRK2 kinase inhibition on alpha-synuclein axonal transport towards the presynaptic terminal. Reduced LRRK2 kinase activity increases alpha-synuclein overlap with presynaptic markers in primary neurons, and increases anterograde axonal transport of alpha-synuclein-GFP. In vivo, LRRK2 inhibition increases alpha-synuclein overlap with glutamatergic, cortico-striatal terminals, and dopaminergic nigral-striatal presynaptic terminals. The findings suggest that LRRK2 kinase activity plays a role in axonal transport, and presynaptic targeting of alpha-synuclein. These data provide potential mechanisms by which LRRK2-mediated perturbations of alpha-synuclein localization could cause pathology in both LRRK2-PD, and idiopathic PD.

scholarly journals Kinesin light chain-1 serine-460 phosphorylation is altered in Alzheimer’s disease and regulates axonal transport and processing of the amyloid precursor protein

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Gábor M. Mórotz ◽  
Elizabeth B. Glennon ◽  
Jenny Greig ◽  
Dawn H. W. Lau ◽  
Nishita Bhembre ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Axonal Transport ◽  
Disease Process ◽  
Precursor Protein ◽  
App Processing ◽  
Amyloidogenic Processing ◽  
Anterograde Axonal Transport

AbstractDamage to axonal transport is an early pathogenic event in Alzheimer’s disease. The amyloid precursor protein (APP) is a key axonal transport cargo since disruption to APP transport promotes amyloidogenic processing of APP. Moreover, altered APP processing itself disrupts axonal transport. The mechanisms that regulate axonal transport of APP are therefore directly relevant to Alzheimer’s disease pathogenesis. APP is transported anterogradely through axons on kinesin-1 motors and one route for this transport involves calsyntenin-1, a type-1 membrane spanning protein that acts as a direct ligand for kinesin-1 light chains (KLCs). Thus, loss of calsyntenin-1 disrupts APP axonal transport and promotes amyloidogenic processing of APP. Phosphorylation of KLC1 on serine-460 has been shown to reduce anterograde axonal transport of calsyntenin-1 by inhibiting the KLC1-calsyntenin-1 interaction. Here we demonstrate that in Alzheimer’s disease frontal cortex, KLC1 levels are reduced and the relative levels of KLC1 serine-460 phosphorylation are increased; these changes occur relatively early in the disease process. We also show that a KLC1 serine-460 phosphomimetic mutant inhibits axonal transport of APP in both mammalian neurons in culture and in Drosophila neurons in vivo. Finally, we demonstrate that expression of the KLC1 serine-460 phosphomimetic mutant promotes amyloidogenic processing of APP. Together, these results suggest that increased KLC1 serine-460 phosphorylation contributes to Alzheimer’s disease.

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.

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