Biophysical characterization of the interactions between human papillomavirus and cell surface glycosaminoglycans at the single particle level

Session

Stream 4 (AFM): Quantitative SPM for Biology, Biomedicine, and Bioinspired Technologies

Authors

Dr. Fouzia Bano (1), Dr. Laura Soria Martinez (2), Dr. Mario Schelhaas (2), Dr. Marta Bally (1)

Affiliations

1. Department of Clinical Microbiology and Wallenberg Centre for Molecular Medicine, Umeå University
2. Institute of Cellular Virology, ZMBE, University of Münster

Keywords

Human Papillomavirus, glycosaminoglycan, TIRF, single particle tracking, AFM force spectroscopy

Abstract text

The recruitment of viral pathogens to host cells is often mediated by carbohydrates on the cell surface. For example, glycosaminoglycans (GAGs), negatively charged oligosaccharides, play a decisive role in initially recruiting and accumulating viruses at the cell surface. Moreover, the degree and type of GAG sulfation has been suggested to be important in modulating the attachment/detachment behavior of enveloped viruses like herpes simplex virus type I (1-3). However, little is known about the biophysical properties of the interactions between non-enveloped virus and GAGs, specifically when it comes to their dynamics. In this study, we probe how the attachment, detachment and diffusion of a non-enveloped virus, human papillomavirus type 16 (HPV16), is regulated on the cell surface. HPV16 is a double-stranded DNA virus of high medical important, as it is the leading cause of cervical cancer (4).Using two powerful single particle techniques: single particle tracking by total internal reflection fluorescence (TIRF) and atomic force microscopy-based single molecule force spectroscopy (AFM-FS) (3,5) alongside with surface-immobilized GAGs (a cell-surface mimic platform that offers tight control on grafting density and presentation of GAGs), we study how specific sulfation patterns on highly sulphated GAGs like heparin influence the binding kinetics and diffusion behaviors of HPV type 16. Our TIRF data show that HPV16 binds with higher affinity to parental heparin as compare to selectively N-Desulphated heparin with no major difference in their diffusion behavior. Our AFM-FS data in excellent agreement with TIRF shows higher binding probability and lower dissociation rate for the interaction of HPV16 and parental heparin further highlighting the importance of N-sulphation on the binding behavior. Taken together, this implies that the type of sulphation of the GAGs has an important functional implication for the viral attachment which may influence entry. 

References

1. Spear et al, J. Virol. 65 1090–1098 (1991) 
2. Tufaro et al., Virology 208 531–539. (1995)
3. Bally et al., Biophys. J113, 1223 (2017) 
4. Kast et al., J. Viorology 87, 6062, (2013) and Schelhaas et al. Cellular microbiol. 15, 1818 (2013)
5. Bally et. al., ACS Chem. Biol. 14, 534−542 (2019)