The rotavirus surface protein VP8 modulates the gate and fence function of tight junctions in epithelial cells.
Rotaviruses constitute a major cause of diarrhea in young mammals. Rotaviruses utilize different integrins as cell receptors, therefore upon their arrival to the intestinal lumen their integrin receptors will be hidden below the tight junction (TJ), on the basolateral membrane. Here we have studied whether the rotavirus outer capsid proteins are capable of opening the paracellular space sealed by the TJ. From the outermost layer of proteins of the rotavirus, 60 spikes formed of protein VP4 are projected. VP4 is essential for virus-cell interactions and is cleaved by trypsin into peptides VP5 and VP8. Here we found that when these peptides are added to confluent epithelial monolayers (Madin-Darby canine kidney cells), VP8 is capable of diminishing in a dose dependent and reversible manner the transepithelial electrical resistance. VP5 exerted no effect. VP8 can also inhibit the development of newly formed TJs in a Ca-switch assay. Treatment with VP8 augments the paracellular passage of non-ionic tracers, allows the diffusion of a fluorescent lipid probe and the apical surface protein GP135, from the luminal to the lateral membrane, and triggers the movement of the basolateral proteins Na+-K+-ATPase, alphanubeta3 integrin and beta1 integrin subunit, to the apical surface. VP8 generates a freeze-fracture pattern of TJs characterized by the appearance of loose end filaments, that correlates with an altered distribution of several TJ proteins. VP8 given orally to diabetic rats allows the enteral administration of insulin, thus indicating that it can be employed to modulate epithelial permeability.
Nava
Porfirio
P
Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (CINVESTAV), Mexico DF 07000, Mexico.
López
Susana
S
Arias
Carlos F
CF
Islas
Socorro
S
González-Mariscal
Lorenza
L
D000284:Administration, Oral; D000595:Amino Acid Sequence; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D062465:Claudin-3; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy; D004195:Disease Models, Animal; D004285:Dogs; D017097:Electric Impedance; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005614:Freeze Fracturing; D007004:Hypoglycemic Agents / Q000493:pharmacokinetics; D007328:Insulin / Q000493:pharmacokinetics; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D062793:Occludin; D010750:Phosphoproteins / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D062826:Zonula Occludens-1 Protein
D062465:Claudin-3; C568124:Cldn3 protein, rat; D007004:Hypoglycemic Agents; D007328:Insulin; D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; C569044:Tjp1 protein, rat; D017361:Viral Nonstructural Proteins; D062826:Zonula Occludens-1 Protein; C079234:NS35 protein, rotavirus