Background: Sialic acids are located at the termini of glycoproteins and glycans, which build the glycocalyx. As such, they are involved in numerous cell-cell interactions. This includes physiological and pathological processes. They interact with lectins, specifically with selectins, factor H, and sialic acid binding immunoglobulin like lectins – Siglecs. Siglecs are emerging as potential therapeutic targets, for treatment of immune cell disorders and cancer.
Aim: Siglec-7 and Siglec-8 are receptors from the Siglec family, and least researched ones. They are expressed on immune cells and play a role in disorders of the immune system. From this point of view, our aim was to conduct a review of research articles, whose main focus are the interactions between Siglec-7 or Siglec-8 with glycomimetics – analogues of sialic acids. In the review, we included small molecules, whose structure is based on the structure of native sialic acids and have drug like properties. Our focus were the selectivity and affinity of binding of these analogues with Siglec-7 and Siglec-8.
Methods: We conducted the search using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We defined the search profile, on the basis of which we conducted the search in PubMed and Web of Science. We included the research articles that mentioned small molecules, that bind to Siglec-7 and Siglec-8, preferentially with a defined Kd or IC50. We included articles, which explain in detail the functions of sialic acids in cancer as well as immune disorders, and articles that examine the structure of Siglec receptors.
Results: According to the PRISMA guidelines, we extracted 21 research articles from PubMed and Web of Science and included them in the review. We categorised the articles according to the country, where the research took place. Another analysis was according to the year of publication of the same articles.
Conclusion: The review showed that the binding affinity of the receptors with native glycans is significantly lower than the binding affinity with glycomimetics. Siglec receptors distinguish a difference between the types of bonds formed between the monosaccharides and show different preferences for different bonding conformations.
|