Andes virus replication and polarized trafficking in epithelial cells.

摘要

Andes virus is a causative agent of Hantavirus pulmonary syndrome (HPS) in South America. In nature, hantaviruses are maintained in a persistently infected rodent host, and human infections occur by inhalation of infected rodent excreta. HPS begins as a prodrome of fever, myalgia, and dyspnea and rapidly progresses to severe pulmonary microvascular leakage, respiratory distress, and shock. Pathology is primarily localized to lung endothelial cells; however, initial replication within the airway epithelium and the mechanisms by which the virus crosses the epithelium to gain access to the endothelium are poorly understood. This study investigated ANDV interactions with the respiratory epithelium and the cellular trafficking pathways involved in virus secretion from epithelial cells.; ANDV infection of Syrian golden hamsters serves as a model of HPS pathogenesis. We developed an in vitro culture of primary hamster tracheal epithelial cells (TECs) in order to study ANDV infection of the respiratory epithelium. The hamster TEC cultures differentiate into a polarized, heterogeneous cellular population that resembles the in vivo hamster trachea containing ciliated, basal, and non-ciliated Clara and goblet cells. ANDV infection of hamster TECs resulted in bidirectional virus secretion without cytopathology or loss of tight junction integrity. The infection was localized to the non-ciliated secretory population, correlating with expression of beta3 integrin, a receptor for pathogenic hantaviruses.; Hantaviruses bud into Golgi membranes; however the pathways involved in virus egress to the plasma membrane have not been determined. RabGTPases, RAM and Rab11, localize to the Golgi and recycling endosome and regulate Golgi to plasma membrane transport. Rab8 and Rab11 colocalized with ANDV nucleocapsid in ANDV-infected Vero epithelial cells and when nucleocapsid was expressed in the absence of other viral proteins. ANDV release from infected Vero cells was decreased by 10-fold when Rab8 and Rab11 expression was downregulated using small interfering RNAs. These studies suggest that following assembly at the Golgi, viral particles egress to the plasma membrane through the recycling endosome via Rab8- and/or Rab11-mediated trafficking pathways. Therefore, in the hamster TEC model, ANDV could be trafficked in a bidirectional fashion by a similar mechanism, giving the virus access to the underlying tissue and endothelium.