Receptor (CD155)-Dependent Endocytosis of Poliovirus and Retrograde Axonal Transport of the Endosome

108

103

We have shown that foot-and-mouth disease virus (FMDV) infection mediated by the integrin ␣v␤6 takes place through clathrin-dependent endocytosis but not caveolae or other endocytic pathways that depend on lipid rafts. Inhibition of clathrin-dependent endocytosis by sucrose treatment or expression of a dominantnegative version of AP180 inhibited virus entry and infection. Similarly, inhibition of endosomal acidification inhibited an early step in infection. Blocking endosomal acidification did not interfere with surface expression of ␣v␤6, virus binding to the cells, uptake of the virus into endosomes, or cytoplasmic virus replication, suggesting that the low pH within endosomes is a prerequisite for delivery of viral RNA into the cytosol. Using immunofluorescence confocal microscopy, FMDV colocalized with ␣v␤6 at the cell surface but not with the B subunit of cholera toxin, a marker for lipid rafts. At 37°C, virus was rapidly taken up into the cells and colocalized with markers for early and recycling endosomes but not with a marker for lysosomes, suggesting that infection occurs from within the early or recycling endosomal compartments. This conclusion was supported by the observation that FMDV infection is not inhibited by nocodazole, a reagent that inhibits vesicular trafficking between early and late endosomes (and hence trafficking to lysosomes). The integrin ␣v␤6 was also seen to accumulate in early and recycling endosomes on virus entry, suggesting that the integrin serves not only as an attachment receptor but also to deliver the virus to the acidic endosomes. These findings are all consistent with FMDV infection proceeding via clathrin-dependent endocytosis.

mentioning

confidence: 71%

Early Events in Integrin αvβ6-Mediated Cell Entry of Foot-and-Mouth Disease Virus

Berryman¹,

Clark²,

Monaghan

et al. 2005

108

103

“…Furthermore, PV dissemination via the neural pathway has been found to rely on a fast retrograde axonal transport system and was inhibited by MAb p286 (34). Moreover, the efficient direct interaction of the hPVR cytoplasmic domain with Tctex-1, a light chain of cytoplasmic dynein (21), has been suggested to play an important role in retrograde transport, together with microtubule integrity (33). Cytoplasmic dynein, a minus-end-directed microtubule-based motor complex (13,14,17,43), is implicated in the transport of early and late endosomes, lysosomes, synaptic vesicles, and endoplasmic reticulum along microtubules (1,8,13,14,17,43).…”

mentioning

confidence: 99%

Receptor-Dependent and -Independent Axonal Retrograde Transport of Poliovirus in Motor Neurons

Ohka

Sakai

Bohnert

et al. 2009

Self Cite

Poliovirus (PV), when injected intramuscularly into the calf, is incorporated into the sciatic nerve and causes an initial paralysis of the inoculated limb in transgenic (Tg) mice carrying the human PV receptor (hPVR/ CD155) gene. We have previously demonstrated that a fast retrograde axonal transport process is required for PV dissemination through the sciatic nerves of hPVR-Tg mice and that intramuscularly inoculated PV causes paralytic disease in an hPVR-dependent manner. Here we showed that hPVR-independent axonal transport of PV was observed in hPVR-Tg and non-Tg mice, indicating that several different pathways for PV axonal transport exist in these mice. Using primary motor neurons (MNs) isolated from these mice or rats, we demonstrated that the axonal transport of PV requires several kinetically different motor machineries and that fast transport relies on a system involving cytoplasmic dynein. Unexpectedly, the hPVR-independent axonal transport of PV was not observed in cultured MNs. Thus, PV transport machineries in cultured MNs and in vivo differ in their hPVR requirements. These results suggest that the axonal trafficking of PV is carried out by several distinct pathways and that MNs in culture and in the sciatic nerve in situ are intrinsically different in the uptake and axonal transport of PV.In humans, paralytic poliomyelitis results from the invasion of the central nervous system by circulating poliovirus (PV), probably via the blood-brain barrier. This conclusion is supported by the finding that circulating PV after intravenous inoculation in mice appears to cross the blood-brain barrier at a high rate in a human PV receptor (hPVR/CD155)-independent manner (44). After the virus enters the central nervous system, it replicates in neurons, especially in motor neurons (MNs), inducing the cell death that causes paralytic poliomyelitis. Along with this route of dissemination, a neuron-specific pathway has been reported in humans (31), monkeys (18), and PV-sensitive transgenic (Tg) mice carrying the hPVR gene (34,37). This neuron-specific pathway appears to be important in causing "provocation poliomyelitis," which is triggered by injuries after PV ingestion (11). Using differentiated PC12 cells and a PV-sensitive Tg mouse line, we have shown that intramuscularly inoculated PV is taken up by endocytosis at synapses.hPVR is a member of the immunoglobulin (Ig) superfamily, with three linked extracellular Ig-like domains, followed by a membrane-spanning domain and a cytoplasmic domain. Two membrane-bound forms (␣ and ␦) and two secreted forms (␤ and ␥) of hPVR derived by alternative splicing are likely to be expressed in human cells (23). Membrane-bound hPVRs are considered to play important roles in the early steps of infection, such as the binding of the virus to the cell surface, its entry into the cell, and the uncoating of the virus. The N-terminal Ig-like domain harbors the sites for PV binding, and antihPVR monoclonal antibodies (MAbs) directed against this region block PV infection (9,24,39).hPVR ...

“…The brain stem is most likely the major target of EV71 infection (2, 8). However, neither the host cell receptor nor the neurotransmission route of EV71 is fully defined.As for poliovirus (PV), two possible routes by which the virus reaches the central nervous system (CNS) have been suggested: the virus either enters the CNS from the blood across the blood-brain barrier (BBB) or is transmitted to the CNS through peripheral nerves via retrograde axonal transport (1,3,14,23). Expression of certain gene segments would be responsible for determining the capacity of PV to spread to the CNS through bloodstream or neuronal pathways (18).…”

mentioning

confidence: 99%

Retrograde Axonal Transport: a Major Transmission Route of Enterovirus 71 in Mice

Chen¹,

Yao²,

Lin³

et al. 2007

151

126

Enterovirus 71 (EV71), a single-positive-stranded RNA virus that belongs to the Enterovirus genus of the Picornaviridae family, is a highly neurotropic virus and has been regarded as the most important neurotropic EV after the eradication of the poliovirus (11). The brain stem is most likely the major target of EV71 infection (2, 8). However, neither the host cell receptor nor the neurotransmission route of EV71 is fully defined.As for poliovirus (PV), two possible routes by which the virus reaches the central nervous system (CNS) have been suggested: the virus either enters the CNS from the blood across the blood-brain barrier (BBB) or is transmitted to the CNS through peripheral nerves via retrograde axonal transport (1,3,14,23). Expression of certain gene segments would be responsible for determining the capacity of PV to spread to the CNS through bloodstream or neuronal pathways (18).In a cynomologus monkey model (12, 13), EV71 showed a wider-spread distribution pattern in the CNS than PV following both intracranial (i.c.) and intravenous inoculations, and monkeys exhibited extrapyramidal signs, including tremor and ataxia. However, after intraspinal inoculation, monkeys developed flaccid paralysis, a pyramidal sign suggesting direct virus invasion in the inoculation site. EV infection and persistence have been implicated in the pathogenesis of certain chronic muscle diseases (17). Furthermore, PV replicated in muscle cells that maintained constant viremia and spread to CNS from peripheral nerves (23). We previously showed that EV71 propagated more effectively in RD (human rhabdomyosarcoma) cells than in SK-N-SH (neuroblastoma) cells and Caco-2 (colorectal adenocarcinoma) cells. Furthermore, after oral (p.o.) inoculation of a mouse-adapted EV71 strain, EV71/MP4, 7-day-old ICR mice developed paralysis, with a mortality rate of 80%. Virus was first seen in the intestine. The virus then spread to muscle and CNS. A vast amount of virus was detected in the CNS and muscle, which led to neuronal loss and rhabdomyolysis of the mice with severe paralysis (21). In this study, we demonstrated that EV71 possesses strong neurotropism and that retrograde axonal transport in neuron cells might represent the major transmission route of EV71 in mice. MATERIALS AND METHODSCells and virus. RD cells (American Type Culture Collection, Manassas, VA) were maintained in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum plus 2 mM L-glutamine, 100 IU penicillin, and 100 g of streptomycin per ml. EV71/MP4 strain, a mouse-adapted strain derived from parental virus EV71/Tainan/4643/98 (GenBank accession number AF304458) (22), was grown in RD cells. Working stocks contained 2 ϫ 10 7 PFU/ml. Experimental infection. Specific-pathogen-free, 7-day-old ICR mice