Abstract
BackgroundHuman cytomegalovirus (HCMV) is the leading infectious cause of vision loss among congenitally infected children. Retinal pericytes play an essential role in maintaining retinal vascular and endothelial cell proliferation. However, the role of retinal pericytes in ocular HCMV pathogenesis is unknown.MethodsRetinal pericytes were exposed to clinical (SBCMV) and lab strains of HCMV; infectivity was analyzed by microscopy, immunofluorescence and qRT-PCR (reverse transcription polymerase chain reaction). Cytokine expression was examined by Luminex assay. Recombinant HCMV-GPF was used to examine viral replication kinetics. A Tricell culture model of the inner blood-retinal barrier (IBRB) was examined for cell type infectivity using immunohistochemistry.ResultsRetinal pericytes expressed the biomarker neuron-glial antigen 2. Antigenic expression profiles for several cytoskeletal, cell adhesion and inflammatory proteins were shared by both retinal and brain pericytes. Infected pericytes showed cytomegalic cytopathology and expressed mRNAs for the major immediate protein (MIE) and HCMV phosphorylated envelop protein 65. qRT-PCR analysis showed full lytic replication of HCMV in retinal pericytes. Pericytes exposed to SBCMV for 9 days expressed higher levels of vascular endothelial cell growth factor mRNA compared to controls. Luminex analysis of supernatants from SBCMV-infected retinal pericytes had increased levels of macrophage inflammatory protein-1α, beta-2 microglobulin (B2-m), matrix metalloproteinase-3 and -9 (MMP3/9), and lower levels of IL-6 and IL-8 compared to controls. At 24 hours post infection, pericytes expressed higher levels of IL-8, TIMP-1 (tissue inhibitor of metalloproteinase-1), and RANTES (regulated upon activation normal T cell-expressed and presumably secreted) but lower levels of MMP9. Time course analysis showed that both brain and retinal pericytes were more permissive for HCMV infection than other cellular components of the BBB (blood-brain barrier) and IBRB. Using a Tricell culture model of the IBRB (retinal endothelial, pericytes, Müller cells), retinal pericytes were most permissive for SBCMV infection. SBCMV infection of this IBRB Tricell mixture for 96 hours resulted in increased levels of IL-6, MMP9, and stem cell factor with a concomitant decrease in granulocyte-macrophage colony-stimulating factor and TNF-alpha.ConclusionIn retinal pericytes, HCMV induces proinflammatory and angiogenic cytokines. In the IBRB, pericytes likely serve as an amplification reservoir which contributes to retinal inflammation and angiogenesis.
Highlights
Human cytomegalovirus (HCMV) is the leading infectious cause of vision loss among congenitally infected children
Pericytes were examined for expression of cytosketal antigenic biomarkers, cellular adhesion antigenic biomarkers (CD68, platelet endothelial cell adhesion molecule-1 (PECAM-1), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), MelCAM-1, E-selectin, von Willebrand factor (VWF), alpha 4 integrin) and inflammatory biomarkers (TNF-alpha, NFkB, RANTES and Tissue Factor)
We found a high degree of similarity in the antigenic expression profiles in human brain and retinal pericytes for those cytoskeletal, cell adhesion and inflammatory biomarkers we tested (Table 1)
Summary
Human cytomegalovirus (HCMV) is the leading infectious cause of vision loss among congenitally infected children. Congenital HCMV infection is the major cause of birth defects, affecting approximately 40,000 children (0.2 to 2% of all live births) in the United States each year [2,3,4,5,6], and is the leading infectious cause of mental retardation and deafness in children [7,8]. It is estimated that approximately 8,000 children are affected each year with some form of neuropathology associated with congenital HCMV infections in the United States [12]. Retinitis due to HCMV infection, which can result in blindness, is the most prevalent ocular disease in individuals with HIV/AIDS [15,16,17,18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
