Dengue Virus Type 2: Protein Binding and Active Replication in Human Central Nervous System Cells

Ma Isabel Salazar,Jaime Diegopérez-Ramírez,María Eugenia Castro-Mussot,Marissa Pérez-García,María Martha García-Flores,Leticia Cedillo-Barrón,Alma Griselda Ramírez-Reyes,Marisol Terreros-Tinoco,Penélope Aguilera

doi:10.1155/2013/904067

Abstract

An increased number of dengue cases with neurological complications have been reported in recent years. The lack of reliable animal models for dengue has hindered studies on dengue virus (DENV) pathogenesis and cellular tropism in vivo. We further investigate the tropism of DENV for the human central nervous system (CNS), characterizing DENV interactions with cell surface proteins in human CNS cells by virus overlay protein binding assays (VOPBA) and coimmunoprecipitations. In VOPBA, three membrane proteins (60, 70, and 130 kDa) from the gray matter bound the entire virus particle, whereas only a 70 kDa protein bound in white matter. The coimmunoprecipitation assays revealed three proteins from gray matter consistently binding virus particles, one clearly distinguishable protein (~32 kDa) and two less apparent proteins (100 and 130 kDa). Monoclonal anti-NS3 targeted the virus protein in primary cell cultures of human CNS treated with DENV-2, which also stained positive for NeuH, a neuron-specific marker. Thus, our results indicate (1) that DENV-2 exhibited a direct tropism for human neurons and (2) that human neurons sustain an active DENV replication as was demonstrated by the presence of the NS3 viral antigen in primary cultures of these cells treated with DENV-2.

Highlights

In recent years, several neurological disorders, such as delirium, coma, amnesia, seizures, meningitis, encephalitis, encephalomyelitis, Guillian-Barresyndrome neuropathies, and intracranial hemorrhages, have been shown to be associated with dengue infections [1,2,3,4,5,6]
Factors secondary to dengue infection caused by thrombocytopenia leading to hemorrhages, liver failure, and electrolyte imbalances are some determinants of encephalopathy during the illness, not of encephalitis
To identify interactions between proteins located on the surface of human central nervous system (CNS) cells and dengue virus (DENV)-2 particles, we carried out virus overlay protein binding assays (VOPBA)

Summary

Introduction

Several neurological disorders, such as delirium, coma, amnesia, seizures, meningitis, encephalitis, encephalomyelitis, Guillian-Barresyndrome neuropathies, and intracranial hemorrhages, have been shown to be associated with dengue infections [1,2,3,4,5,6]. A recent study of fatal dengue cases established that CNS involvement occurs more frequently than was previously reported; dengue virus (DENV) was found in 48.8% of the cerebrospinal fluids (CSF) analyzed. The neurologic diagnoses for these patients were the following: encephalitis (46.3%), meningoencephalitis (34.1%), and meningitis (19.5%) [14]. These authors reported that the major clinical manifestations observed in these individuals were fever, headache, irritability, breathlessness, vomiting, muscle pain, tiredness, abdominal pain, somnolence, restlessness, dizziness, cough, seizure, coma, and neck stiffness [14]

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Conclusion