The Underlying Mechanism of 3-Hydroxyphthalic Anhydride-Modified Bovine Beta-Lactoglobulin to Block Human Papillomavirus Entry Into the Host Cell

Abstract

We have previously demonstrated that 3-hydroxyphthalic anhydride (3HP)-modified bovine beta-lactoglobulin (3HP-β-LG) is highly effective in inhibiting entry of pseudovirus (PsV) of high- and low-risk human papillomavirus (HPV) into the target cell. Intravaginally applied 3HP-β-LG-containing vaginal gel could significantly inhibit HPV infection and reduce viral load in the cervical region. However, we still do not understand the underlying molecular mechanism by which 3HP-β-LG is able to inhibit HPV infection. Here, though, we showed that 3HP-β-LG did not inactivate HPV PsV, but rather blocked entry of HPV PsV into the target cell via its interaction with virus, not cell. It bound to the positively charged region in the HPV L1 protein, suggesting that 3HP-β-LG binds to HPV L1 protein through the interaction between the negatively charged region in 3HP-β-LG and the positively charged region in HPV L1 protein, thus competitively blocking the binding of HPV to the receptor on the basement membrane in vaginal mucosa. Although 3HP-modified chicken ovalbumin (3HP-OVA) also carries high net negative charges, it exhibited no anti-HPV activity, suggesting that the interaction between 3HP-modified protein and HPV L1 protein relies on both electrostatic and matchable conformation of the binding sites in both proteins. When topically applied, 3HP-β-LG did not enter the host cell or blood circulation. These findings suggest that 3HP-β-LG targets HPV L1 protein and blocks HPV entry into the host cell, thus being safe and effective for topical application in the treatment of HPV infection.

3-Hydroxyphthalic Anhydride-Modified Chicken Ovalbumin as a Potential Candidate Inhibits SARS-CoV-2 Infection by Disrupting the Interaction of Spike Protein With Host ACE2 Receptor

“…Our previous studies have also certified that HP-OVA has no harmful or deleterious impact on the function of immune cells ( Li et al, 2010a ). Actually, anhydride-modiβed proteins, such as anhydride-modiβed bovine β-lactoglobulin, have been studied and utilized as microbicides against HIV and HPV in clinics for years, and their effectiveness and safety as drugs have been veriβed ( Neurath et al, 1996 ; Guo et al, 2016 ; Hua et al, 2019 ).…”

“…Our previous studies have reported that several kinds of viruses, including human immunodeficiency virus (HIV), human papillomavirus (HPV), respiratory syncytial virus (RSV), and novel human coronavirus MERS-CoV, can be inhibited at the viral entry step by anhydride-modified proteins ( Li et al, 2010a ; Zhao et al, 2013 ; Hua et al, 2019 ). Furthermore, one kind of anhydride-modified bovine protein, β-lactoglobulin (β-LG), was clinically applied to treat HPV infection ( Hua et al, 2019 ). Therefore, we decided to investigate whether anhydride-modified proteins could be utilized as anti-SARS-CoV-2 antivirals.…”

Advances in Targeting HPV Infection as Potential Alternative Prophylactic Means

“…Also, HPV58-PsV entry in vitro was found to be inhibited by JB01 with an IC 50 of 0.28 µg/mL [151]. Mechanistically, the negatively charged regions on JB01 were shown to bind to the positively charged region of the HPV L1 protein, and this interaction was proposed to competitively block the binding of HPV to the receptor on the basement membrane in the vaginal mucosa (Figure 1) [151].…”

Affinity-Controlled Double-Network Hydrogel Facilitates Long-Term Release of Anti-Human Papillomavirus Protein

“…Due to a lack of delivery system and high solubility of 3-hydroxyphthalic anhydride-modified bovine beta-lactoglobulin [30], existing studies can only culture cells directly in a protein-containing solution [31]. As for the in vivo application, the previous clinical application method was to use it in a gel, but it needs to be applied once every two days, which is inconvenient for patients [33]. Therefore, the hydrogel system with controlled release function in this study has great application prospects.…”