The specificity of the malarial VAR2CSA protein for chondroitin sulfate depends on 4-O-sulfation and ligand accessibility
Journal article, 2021
Placental malaria infection is mediated by the binding of the malarial VAR2CSA protein to the placental glycosaminoglycan, chondroitin sulfate. Recombinant subfragments of VAR2CSA (rVAR2) have also been shown to bind specifically and with high affinity to cancer cells and tissues, suggesting the presence of a shared type of oncofetal chondroitin sulfate (ofCS) in the placenta and in tumors. However, the exact structure of ofCS and what determines the selective tropism of VAR2CSA remains poorly understood. In this study, ofCS was purified by affinity chromatography using rVAR2 and subjected to detailed structural analysis. We found high levels of N-acetylgalactosamine 4-O-sulfation (∼80-85%) in placenta- and tumor-derived ofCS. This level of 4-O-sulfation was also found in other tissues that do not support parasite sequestration, suggesting that VAR2CSA tropism is not exclusively determined by placenta- and tumor-specific sulfation. Here, we show that both placenta and tumors contain significantly more chondroitin sulfate moieties of higher molecular weight than other tissues. In line with this, CHPF and CHPF2, which encode proteins required for chondroitin polymerization, are significantly upregulated in most cancer types. CRISPR/Cas9 targeting of CHPF and CHPF2 in tumor cells reduced the average molecular weight of cell-surface chondroitin sulfate and resulted in a marked reduction of rVAR2 binding. Finally, utilizing a cell-based glycocalyx model, we showed that rVAR2 binding correlates with the length of the chondroitin sulfate chains in the cellular glycocalyx. These data demonstrate that the total amount and cellular accessibility of chondroitin sulfate chains impact rVAR2 binding and thus malaria infection.
Author
Charlotte B. Spliid
University of California at San Diego (UCSD)
University of Copenhagen
Alejandro Gomez Toledo
University of California at San Diego (UCSD)
Lund University
Patience Sanderson
University of Georgia
Yang Mao
Sun Yat-Sen University
Guangdong Provincial Key Laboratory of Drug Non-Clinical Evaluation and Research
Francesco Gatto
Chalmers, Biology and Biological Engineering, Systems and Synthetic Biology
Tobias Gustavsson
University of Copenhagen
Swati Choudhary
University of Copenhagen
Ana L. Saldanha
University of Copenhagen
Rasmus P. Vogelsang
Zealand University Hospital
Ismail Gögenur
Zealand University Hospital
Thor G. Theander
University of Copenhagen
Franklin E. Leach
University of Georgia
I. Jonathan Amster
University of Georgia
Jeffrey D. Esko
University of California at San Diego (UCSD)
Ali Salanti
University of Copenhagen
Thomas Mandel Clausen
University of Copenhagen
University of California at San Diego (UCSD)
Journal of Biological Chemistry
0021-9258 (ISSN) 1083-351X (eISSN)
Vol. 297 6 101391Subject Categories
Cell and Molecular Biology
Immunology in the medical area
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
DOI
10.1016/j.jbc.2021.101391
PubMed
34762909