Glycoproteins Presenting Galactose and N-Acetylgalactosamine in Human Seminal Plasma as Potential Players Involved in Immune Modulation in the Fertilization Process

Abstract

In light of recent research, there is increasing evidence showing that extracellular semen components have a significant impact on the immune reaction of the female partner, leading to the tolerogenic response enabling the embryo development and implantation as well as further progress of healthy pregnancy. Seminal plasma glycoproteins are rich in the unique immunomodulatory glycoepitopes that may serve as ligands for endogenous lectins that decorate the surface of immune cells. Such interaction may be involved in modulation of the maternal immune response. Among immunomodulatory glycans, Lewis type antigens have been of interest for at least two decades, while the importance of T/Tn antigens and related structures is still far from understanding. In the current work, we applied two plant lectins capable of distinguishing glycoepitopes with terminal GalNAc and Gal to identify glycoproteins that are their efficient carriers. By means of lectin blotting and lectin affinity chromatography followed by LC-MS, we identified lactotransferrin, prolactin inducible protein as well as fibronectin and semenogelins 1 and 2 as lectin-reactive. Net-O-glycosylation analysis results indicated that the latter three may actually carry T and/or Tn antigens, while in the case of prolactin inducible protein and lactotransferrin LacdiNAc and lactosamine glycoepitopes were more probable. STRING bioinformatics analysis linked the identified glycoproteins in the close network, indicating their involvement in immune (partially innate) processes. Overall, our research revealed potential seminal plasma ligands for endogenous Gal/GalNAc specific lectins with a possible role in modulation of maternal immune response during fertilization.

Hybridization altered the gut microbiota of pigs

“…Interestingly, the current study shows that galactose metabolism in F4 was significantly higher than that in F0 and Duroc; this might be also related to the significantly enriched Lactobacillus and Bifidobacterium in F4. Numerous studies reported that both Lactobacillus and Bifidobacterium could ferment lactose into galactose ( de Vries and Stouthamer, 1968 ; Turner and Martley, 1983 ; Hickey et al, 1986 ), which is involved in several physiological functions, such as protecting the intestinal epithelial barrier and improving immune function ( Salkovic-Petrisic, 2021 ; Szczykutowicz et al, 2021 ). Among them, Galacto-Oligo Saccharides (GOS) could also promote the proliferation of Lactobacillus and Bifidobacterium as well as the production of lactic acid and butyric acid ( Dai et al, 2019 ).…”

Ligand Recognition by the Macrophage Galactose-Type C-Type Lectin: Self or Non-Self?—A Way to Trick the Host’s Immune System

“…Our recent study revealed the glycoproteins of seminal plasma, which are potential carriers of O-glycans terminated with Gal and GalNAc residues, including T and Tn antigens [172]. As already mentioned, both T and its precursor Tn antigen are hidden in normal cells but selectively exposed on cancer cells [87].…”

“…The presence of these glycoepitopes on identified glycoproteins makes them candidates for ligands of endogenous galactose-specific lectins, such as galectins or MGL. As potential carriers of GalNActerminated glycans, which are preferred by the MGL receptor, our analysis indicated prolactin-inducible protein (PIP), semenogelin-1 (SEMG1), semenogelin-2 SEMG2, lactotransferrin (LTF), prostate-specific antigen (KLK3), and fibronectin (FN1) [172].…”

Insights into the Antibacterial Activity of Prolactin-Inducible Protein against the Standard and Environmental MDR Bacterial Strains

“…Innate immunity plays an important role in human health [ 1 ]. During infection, injury, and disease conditions, the metabolism or nutritional homeostasis of the body is disturbed, involving various signaling pathways and secondary messenger molecules [ 2 , 3 ]. Innate immune responses protect our body through various alterations such as modulating membrane composition, antioxidants or cellular redox levels, and cytokines production [ 4 , 5 ].…”