A 3- O -Sulfated Heparan Sulfate Binding Peptide Preferentially Targets Herpes Simplex Virus 2-Infected Cells

Abstract

Herpes simplex virus 2 (HSV-2) is the primary cause of genital herpes, which is one of the most common sexually transmitted viral infections worldwide and a major cofactor for human immunodeficiency virus infection. The lack of an effective vaccine or treatment and the emergence of drug-resistant strains highlight the need for developing new antivirals for HSV-2. Here, we demonstrate that a low-molecular-weight peptide isolated against 3- O -sulfated heparan sulfate (3-OS HS) can efficiently block HSV-2 infection. Treatment with the peptide inhibited viral entry and cell-to-cell spread both in vitro and in vivo using a mouse model of genital HSV-2 infection. Quite interestingly, the peptide showed a preferential binding to HSV-2-infected cells, with more than 200% increased binding compared to uninfected cells. Our additional results show that heparan sulfate expression is upregulated by 25% upon HSV-2 infection, which is a significant new finding that could be exploited for designing new diagnostic tests and treatment strategies against HSV-2-infected cells. In addition, our results also raise the possibility that 3-OS HS modifications within HS may be upregulated even more to accommodate for a significantly higher increase in the peptide binding to the infected cells.

Zebrafish: Modeling for Herpes Simplex Virus Infections

“…33 The differences also point to the possibility that the levels of HSV infectivity during zebrafish development from early stages of embryos to adult form may vary and a lot of it can be monitored using time-lapse confocal imaging. Since our group has already identified and characterized HS recognizing anti-HS and anti-3-OS HS peptides, 7,8 it will be interesting to test the effects of the peptides in blocking HSV infection and associated inflammation in the zebrafish model. Similarly, testing HSV infectivity in receptor-specific knockouts will also be very useful to understand their in vivo significance.…”

“…21 Ideally, zebrafish in a 96-well format can be treated with antibodies 50 or compounds targeting specific cells/tissues or modified antiviral peptides with an objective to have higher efficacy. For instance, peptide generated against human 3-OS HS 7,8 can be tested against the zebrafish 3-OS HS model since virus is able to infect zebrafish. Likewise, elucidating the antiviral activity of new drugs or peptides can be done and activation or blockage of specific pathways may be identified.…”

“…5,6 In addition, phage display screening generated peptides against HS and 3-OS HS significantly impaired HSV infection in both cell culture and in vivo mouse corneal model. 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.…”

“…4 Using primary human cell culture model and a mouse model we have demonstrated the in vivo significance of HS and 3-OS HS in HSV-1 infection. [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.…”

“…Further, an advantage of using a zebrafish model is to test peptides generated against specific 3-OST isoforms. 7,8 The kinetics of inhibition can be determined in short duration of time together with toxicological evaluation, which again is not possible with present murine and rabbit models against HSV infection. The information generated by the zebrafish experiments can identify useful inhibitors to prevent HSV-1-induced pathological damages especially during ocular corneal infection or neuronal damages.…”