PhD Scientific Days 2025

Poster Session I. - N: Health Sciences

Characterizing the Interaction between Placental Galectins and Soluble Immune Proteins

Name of the presenter

Farkas Emese

Institute/workplace of the presenter

HUN-REN TTK, Institute of Molecular Life Sciences, Systems Biology of Reproduction Research Group

Authors

Emese Farkas¹, Orsolya Oravecz², Máté Posta¹, András Szilágyi³, Barbara Uzonyi⁴, Mihály Józsi⁴, Nándor Gábor Than⁵, Andrea Balogh³

1: Systems Biology of Reproduction Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Budapest, Hungary; 2Doctoral College, Károly Rácz Conservative Medicine Division, Semmelweis University, Budapest, Hungary
2: Systems Biology of Reproduction Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Budapest, Hungary; Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
3: Systems Biology of Reproduction Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Budapest, Hungary
4: Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary; HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
5: Systems Biology of Reproduction Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Budapest, Hungary; Department of Obstetrics and Gynecology, Semmelweis University, Budapest, Hungary; Maternity Private Clinic of Obstetrics and Gynecology, Budapest, Hungary

Text of the abstract

Proper immune adaptation at the maternal-fetal interface is essential for a successful pregnancy, with several immunomodulatory factors contributing to this finely tuned balance. Among them, galectins (Gal), recognizing β-galactoside-containing glycoconjugates, have emerged as key regulators of immune functions. In humans, 16 galectins have been identified, each playing distinct yet overlapping roles by modulating e.g., cytokine production and immune cell activation. Placental galectins – Gal-13 and Gal-14 – are uniquely expressed by the syncytiotrophoblast, where they contribute to maternal immune adaptation. Their dysregulation is linked to adverse pregnancy outcomes, such as miscarriage and preeclampsia. Although emerging evidence suggests that galectins interact with complement components and other immune proteins, currently, no data is available on the direct binding of placental galectins to soluble immune proteins with functional relevance. Therefore, we aimed to identify immune binding partners of Gal-13 and Gal-14 in human blood and model the 3D structure of these complexes.
Using ELISA, we screened potential binding partners of Gal-13 and Gal-14 in human plasma, confirmed the binding with purified proteins, and assessed whether these interactions were carbohydrate-dependent. We also performed structural modeling of Gal-immune protein complexes using AlphaFold 3, Chai-1, and Boltz-1.
ELISA experiments demonstrated that Gal-13 and Gal-14 can bind to various immune proteins, including IgG, CRP, and complement components such as C1q, FH, and FHR1 and -5 in a concentration-dependent manner. The interaction of Gal-13 with IgG, C1q, and FH was carbohydrate-dependent, evidenced by reduced binding in the presence of lactose. Computational modeling further supported the likelihood of favorable binding modes between placental galectins and immune proteins.
In conclusion, our results show that Gal-13 and Gal-14 bind to several immune proteins in vitro, with some of the interactions being carbohydrate-dependent. However, further experiments are needed to determine the functional relevance of placental Gal–immune protein complexes. By characterizing the molecular interactions between Gal-13/Gal-14 and immune proteins, our findings may provide new insights into immunoregulatory mechanisms essential for a healthy pregnancy and fetal development.