bi7b00875_si_001.pdf (1.33 MB)
O‑GalNAcylation of RANTES Improves Its Properties as a Human Immunodeficiency Virus Type 1 Entry Inhibitor
journal contribution
posted on 2017-12-04, 00:00 authored by Xiaoyang Guan, Patrick K. Chaffey, Huan Chen, Wei Feng, Xiuli Wei, Liu-Meng Yang, Yuan Ruan, Xinfeng Wang, Yaohao Li, Kimberly B. Barosh, Amy H. Tran, Jaimie Zhu, Wei Liang, Yong-Tang Zheng, Xu Wang, Zhongping TanMany
human proteins have the potential to be developed as therapeutic
agents. However, side effects caused by direct administration of natural
proteins have significantly slowed expansion of protein therapeutics
into the clinic. Post-translational modifications (PTMs) can improve
protein properties, but because of significant knowledge gaps, we
are considerably limited in our ability to apply PTMs to generate
better protein therapeutics. Here, we seek to fill the gaps by studying
the PTMs of a small representative chemotactic cytokine, RANTES. RANTES
can inhibit HIV-1 infection by competing with it for binding to receptor
CCR5 and stimulating CCR5 endocytosis. Unfortunately, RANTES can induce
strong signaling, leading to severe inflammatory side effects. We
apply a chemical biology approach to explore the potential of post-translationally
modified RANTES as safe inhibitors of HIV-1 infection. We synthesized
and systematically tested a library of RANTES isoforms for their ability
to inhibit inflammatory signaling and prevent HIV-1 infection of primary
human cells. Through this research, we revealed that most of the glycosylated
variants have decreased inflammation-associated properties and identified
one particular glyco variant, a truncated RANTES containing a Galβ1–3GalNAc
disaccharide α-linked to Ser4, which stands out as having the
best overall properties: relatively high HIV-1 inhibition potency
but also weak inflammatory properties. Moreover, our results provided
a structural basis for the observed changes in the properties of RANTES.
Taken together, this work highlights the potential importance of glycosylation
as an alternative strategy for developing CCR5 inhibitors to treat
HIV-1 infection and, more generally, for reducing or eliminating unwanted
properties of therapeutic proteins.