Zebrafish-Encoded 3-O-Sulfotransferase-3 Isoform Mediates Herpes Simplex Virus Type 1 Entry and Spread

Abstract

Heparan sulfate proteoglycans modified by human glucosaminyl 3-O-sulfotransferase-3 (3-OST-3) isoform generates the cellular receptor for herpes simplex virus type 1 (HSV-1). Interestingly, the ability of zebrafish (ZF)-encoded 3-OST-3 isoform to modify heparan sulfate to mediate HSV-1 entry and cell-cell fusion has not been determined although it is predominantly expressed in ZF, a popular model organism to study viral infections. Here, we demonstrate that expression of ZF-encoded 3-OST-3 isoform renders the resistant Chinese hamster ovary (CHO-K1) cells to become susceptible for HSV-1 entry. The following lines of evidence support the important role of ZF-encoded 3-OST-3 isoform as the mediator of HSV-1 entry into CHO-K1 cells: (1) ZF 3-OST-3-expressing CHO-K1 cells were able to preferentially bind HSV-1 glycoprotein D, and (2) CHO-K1 cells expressing ZF-encoded 3-OST-3 acquire the ability to fuse with cells expressing HSV-1 glycoproteins. Finally, knocking down 3-OST-3 receptor by siRNA in ZF fibroblasts cells significantly reduced HSV-1 entry and glycoprotein D binding to cells. Taken together, our results provide novel insight into the significance of ZF 3-OST-3 isoform as an HSV-1 entry and fusion receptor and its potential involvement in the HSV-1 disease model of ZF.

Zebrafish: Modeling for Herpes Simplex Virus Infections

“…[5][6][7][8] Quite interestingly, zebrafish Danio rerio widely expresses 3-OSTs, which are required for embryonic development and also for generating HSV receptors. [9][10][11][12][13][14] Supporting the idea that zebrafish 3-OSTs can generate the receptors, we have found evidence that similar to the human 3-OST-3 isoform, zebrafish encoded 3-OST-3 also allows HSV-1 entry. 9 In addition, zebrafish embryos are susceptible to HSV infection and the zebrafish model is now emerging as a new model system for host-pathogen interactions, largely because the zebrafish larvae are transparent and thus, highly suited for in vivo imaging and cost effective high throughput screening.…”

“…[9][10][11][12][13][14] Supporting the idea that zebrafish 3-OSTs can generate the receptors, we have found evidence that similar to the human 3-OST-3 isoform, zebrafish encoded 3-OST-3 also allows HSV-1 entry. 9 In addition, zebrafish embryos are susceptible to HSV infection and the zebrafish model is now emerging as a new model system for host-pathogen interactions, largely because the zebrafish larvae are transparent and thus, highly suited for in vivo imaging and cost effective high throughput screening. Based on the above attractive promises, zebrafish system provides a unique opportunity to understand many aspects of HSV infection such as host cell tropism, clinical pathologies of the disease and associated inflammation together with immune response to the infection via live in vivo imaging.…”

“…7,8 Recently, our group provided the first evidence of zebrafish encoded 3-OST modified HS receptor mimicking human 3-OST generated HS in allowing HSV-1 entry and spread. [9][10][11] Our results raised the possibility that zebrafish can provide a reasonable ground to study the role of 3-OST generated receptors in HSV-1 infection by making 3-OST isoform-specific knockouts. Zebrafish embryos can be microinjected with moroholinos at 1-4 cell stage to target the specific 3-OST gene.…”

“…Using Chinese hamster ovary (CHO-K1) cells transiently expressing zebrafish encoded 3-OST-2 and 3-OST-3 isoforms resulted in HSV-1 infection. 9,10 More direct and visual evidence of HSV-1 infection was demonstrated by using green fluorescent protein (GFP)-tagged HSV-1 (K26GFP) virions, which clearly infected CHO-K1 cells expressing zebrafish encoded 3-OST-3. The infection was also confirmed by high resolution electron microscopy.…”

“…The infection was also confirmed by high resolution electron microscopy. 9,16 Future studies to characterize the other members of the zebrafish 3-OST family will determine their role in mediating HSV infection of specific cells and tissues. Because HSV-1 is a neurotropic virus, it is therefore critical to determine the role of the 3-OS HS receptor in promoting pathology in the brain region of zebrafish embryo during HSV-1 infection.…”