Cell Surface Research Articles

Neurexin facilitates glycosylation of Dystroglycan to sustain muscle architecture and function in Drosophila

Neurexin, a molecule associated with autism spectrum disorders, is thought to function mainly in neurons. Recently, it was reported that Neurexin is also present in muscle, but the role of Neurexin in muscle is still poorly understood. Here, we demonstrate that the overexpression of Neurexin in muscles effectively restored the locomotor function of Drosophila neurexin mutants, while rescuing effects are observed within the nervous. Notably, the defects in muscle structure and function caused by Neurexin deficiency were similar to those caused by mutations in dystroglycan, a gene associated with progressive muscular dystrophy. The absence of Neurexin leads to muscle attachment defects, emphasizing the essential role of Neurexin in muscle integrity. Furthermore, Neurexin deficiency reduces Dystroglycan glycosylation on the cell surface, which is crucial for maintaining proper muscle structure and function. Finally, Neurexin guides Dystroglycan to the glycosyltransferase complex through interactions with Rotated Abdomen, a homolog of mammalian POMT1. Our findings reveal that Neurexin mediates muscle development and function through Dystroglycan glycosylation, suggesting a potential association between autism spectrum disorders and muscular dystrophy.

In situ editing of tumour cell membranes induces aggregation and capture of PD-L1 membrane proteins for enhanced cancer immunotherapy

Immune checkpoint blockade (ICB) therapy has emerged as a new therapeutic paradigm for a variety of advanced cancers, but wide clinical application is hindered by low response rate. Here we use a peptide-based, biomimetic, self-assembly strategy to generate a nanoparticle, TPM1, for binding PD-L1 on tumour cell surface. Upon binding with PD-L1, TPM1 transforms into fibrillar networks in situ to facilitate the aggregation of both bound and unbound PD-L1, thereby resulting in the blockade of the PD-1/PD-L1 pathway. Characterizations of TPM1 manifest a prolonged retention in tumour ( > 7 days) and anti-cancer effects associated with reinvigorating CD8+ T cells in multiple mice tumour models. Our results thus hint TPM1 as a potential strategy for enhancing the ICB efficacy.

Synthesis of SulfoCy5‐ and SulfoCy7‐αGalCer Probes as Chemical Tools for Investigating the Uptake of Liposomal αGalCer Conjugates by Antigen Presenting Cells

Abstractα‐Galactosylceramide (αGalCer) is a synthetic glycolipid that, when loaded into the CD1d receptor of antigen presenting cells, activates iNKT cells to coordinate the generation of both innate and adaptive immune responses. In vaccines, the αGalCer adjuvant is generally delivered in liposomes, but interestingly, little is known about the intracellular fate of αGalCer‐antigen conjugates resulting in the absence of clear “design rules” for this type of compounds and their formulations. To unravel the uptake mechanism of liposomal αGalCer conjugates and understand the fate of its components, we synthesized sulfoCy7‐αGalCer 1 and sulfoCy5‐αGalCer 2. The fluorescent probes were obtained from a linker‐functionalized αGalCer, which was then modified with sulfoCy7/sulfoCy5. After formulation in liposomes, the cellular presentation was studied in a murine dendritic cell line using fluorescence imaging and flow cytometry. Imaging indicates that liposomes loaded with sulfoCy5‐αGalCer are taken up by DC2.4 cells in a heterogeneous and concentration‐dependent manner. Additionally, fluorescence antibody staining confirms that αGalCer is ultimately presented by CD1d receptors, but importantly is cleaved from sulfoCy5 before reaching the cell surface. These results validate our synthetic probes as useful in mechanistic studies of the uptake of αGalCer‐antigen conjugates as shown here for DC2.4 cells.

Mammalian cell-based production of glycans, glycopeptides and glycomodules

Access to defined glycans and glycoconjugates is pivotal for discovery, dissection, and harnessing of a range of biological functions orchestrated by cellular glycosylation processes and the glycome. We previously employed genetic glycoengineering by nuclease-based gene editing to develop sustainable production of designer glycoprotein therapeutics and cell-based glycan arrays that display glycans in their natural context at the cell surface. However, access to human glycans in formats and quantities that allow structural studies of molecular interactions and use of glycans in biomedical applications currently rely on chemical and chemoenzymatic syntheses associated with considerable labor, waste, and costs. Here, we develop a sustainable and scalable method for production of glycans in glycoengineered mammalian cells by employing secreted Glycocarriers with repeat glycosylation acceptor sequence motifs for different glycans. The Glycocarrier technology provides a flexible production platform for glycans in different formats, including oligosaccharides, glycopeptides, and multimeric glycomodules, and offers wide opportunities for use in bioassays and biomedical applications.

Role of mucous cells in the defence system of the cnidarian Actinia equina (Linnaeus, 1758): The keystone of evolution

AbstractCnidarians are the first phylum of metazoans to exhibit a functional mucus layer. In evolution, mucous cells perform the classical secretory function of mucus and act as sentinels for external insults, particularly in mammals. However, this topic has not been much analysed in the lower metazoans. This study aims to investigate the role of mucous cells in Actinia equina (Anthozoa, Hexacorallia) (Linnaeus, 1758) by using confocal microscopy and bioinformatics. The results show colocalization of Toll‐like receptor 2 (TLR2) and Mucin2 (MUC2) on these cells, suggesting a crosstalk between defence response and mucus secretion in cnidarians. Furthermore, the presence of TLR2 on the surface of mucous cells suggests their involvement in host defence responses, as occurs in vertebrates. Moreover, through in silico analysis, we confirmed the presence of orthologous genes for the tested antibodies, providing additional evidence to support our results from an evolutionary perspective. These data suggest that mucous cells play a defensive role throughout evolution, helping us understand how these cells have developed and adapted across phylogenesis. This information also provides new insights into the defensive strategies of invertebrates and clarifies their evolutionary history.

Glioma–Astrocyte connexin43 confers temozolomide resistance through activation of the E2F1/ERCC1 axis

Abstract Background Glioma is the most prevalent and lethal tumor of the central nervous system. Routine treatment with Temozolomide (TMZ) would unfortunately result in inevitable recurrence and therapy resistance, severely limiting therapeutic efficacy. Tumor associated astrocytes (TAAs) are key components of the tumor microenvironment and increasing evidence has demonstrated that aberrant expression of Connexin43 (Cx43) was closely associated with glioma progression and TMZ resistance. However, the specific role of Cx43 in mediating TMZ resistance through glioma and astrocyte interactions has not been fully explored. Methods The expression and prognostic value of Cx43 were evaluated in tumor samples and clinical databases. ShRNA-medicated knockdown and Gfap-Cre Cx43flox/flox gene mouse were used to assessed the role and functional significance of Cx43 in vitro and in vivo. Moreover, we performed mass spectrometry analysis, chromatin immunoprecipitation, and other biochemical assays to define the molecular mechanisms by which Cx43 promotes TMZ resistance. Results We confirmed that upregulation of Cx43 expression between TAAs and glioma cells contributed to TMZ resistance and tumor recurrence. Genetic knockdown or pharmacological inhibition of Cx43 enhanced TMZ-induced cytotoxicity. Mechanistically, elevated Cx43 expression induced β-catenin accumulation at the cell surface of glioma cells, suppressing TCF/LEF transcription, This led to impaired miR-205-5p expression and subsequent activation of E2F1/ERCC1 axis, which eventually led to chemoresistance. Conclusions Our study reveals a novel regulatory mechanism in which the Cx43/miR-205-5p/E2F1/ERCC1 axis contributes to TMZ resistance in glioma. These findings further highlight the potential of targeting Cx43 as a therapeutic strategy in glioma.

Physicochemical Characterization of Polysaccharide–Protein Carriers with Immobilized Yeast Cells Obtained Using the Freeze-Drying Technique

New techniques for the immobilization of yeast cells have the potential for enhancement of the beer production process. Alongside conventional materials for cell immobilization, there is a rising trend toward polysaccharide–protein systems. This study focused on the immobilization of yeast cells (Saccharomyces pastorianus) via a freeze-drying process. The whey protein isolate, sodium alginate, maltodextrin, inulin, and their blends were used for carrier preparation. The effect of a 1.0% inulin solution as a cryoprotectant on the viability of the yeast cells after the freeze-drying process was also analyzed. The powders were assessed for cell viability, moisture content, water activity, solubility, particle size, and surface charge. According to the results, the addition of whey proteins reduced the moisture content, while solubility did not significantly decrease. Samples containing whey protein showed slight diameter variations. The negative surface charge observed in all samples, especially the control, indicates a cell’s tendency to aggregate, demonstrated by optical microscopy. SEM micrographs showed successful cell immobilization in polysaccharide–protein carriers. Furthermore, inulin and whey protein addition enhanced cell protection during the immobilization of cells. The freeze-drying technique demonstrates efficacy in immobilization of yeast cells, indicating its potential for applications in the food and beverage industry.

Regulated N-glycosylation controls chaperone function and receptor trafficking

One-fifth of human proteins are N-glycosylated in the endoplasmic reticulum (ER) by two oligosaccharyltransferases, OST-A and OST-B. Contrary to the prevailing view of N-glycosylation as a housekeeping function, we identified an ER pathway that modulates the activity of OST-A. Genetic analyses linked OST-A to HSP90B1, an ER chaperone for membrane receptors, and CCDC134, an ER luminal protein. During its translocation into the ER, an N-terminal peptide in HSP90B1 templates the assembly of a translocon complex containing CCDC134 and OST-A that protects HSP90B1 during folding, preventing its hyperglycosylation and degradation. Disruption of this pathway impairs WNT and IGF1R signaling and causes the bone developmental disorder osteogenesis imperfecta. Thus, N-glycosylation can be regulated by specificity factors in the ER to control cell surface receptor signaling and tissue development.

TMED inhibition suppresses cell surface PD-1 expression and overcomes T cell dysfunction

BackgroundBlockade of the programmed cell death protein 1 (PD-1) immune checkpoint (ICB) is revolutionizing cancer therapy, but little is known about the mechanisms governing its expression on CD8 T cells....

ApoE Receptor-2 R952Q Variant in Macrophages Elevates Soluble LRP1 to Potentiate Hyperlipidemia and Accelerate Atherosclerosis in Mice.

apoER2 (apolipoprotein E receptor-2) is a transmembrane receptor in the low-density lipoprotein receptor (LDLR) family with unique tissue expression. A single-nucleotide polymorphism that encodes the R952Q sequence variant has been associated with elevated plasma cholesterol levels and increased myocardial infarction risk in humans. The objective of this study was to delineate the mechanism underlying the association between the apoER2 R952Q variant and increased atherosclerosis risk. An apoER2 R952Q mouse model was generated using a CRISPR/Cas9 strategy, intercrossed with LDLR knockout mice, followed by feeding a Western-type high-fat high-cholesterol diet for 16 weeks. Atherosclerosis was investigated by immunohistology. Plasma lipids and lipid distributions among the various lipoprotein classes were analyzed by colorimetric assay. Tissue-specific effects of the R952Q sequence variant on atherosclerosis were analyzed by bone marrow transplant studies. sLRP1 (soluble low-density lipoprotein receptor-related protein 1) was measured in plasma and conditioned media from bone marrow-derived macrophages by ELISA and GST-RAP (glutathione S-transferase-receptor-associated protein) pull-down, respectively. P38 MAPK (mitogen-activated protein kinase) phosphorylation in VLDL (very-low-density lipoprotein)-treated macrophages was determined by Western blot analysis. Consistent with observations in humans with this sequence variant, the apoER2 R952Q mutation exacerbated diet-induced hypercholesterolemia, via impediment of plasma triglyceride-rich lipoprotein clearance, to accelerate atherosclerosis in Western diet-fed LDLR knockout mice. Reciprocal bone marrow transplant experiments revealed that the apoER2 R952Q mutation in bone marrow-derived cells instead of non-bone marrow-derived cells was responsible for the increase in hypercholesterolemia and atherosclerosis. Additional data showed that the apoER2 R952Q mutation in macrophages promotes VLDL-induced LRP1 (low-density lipoprotein receptor-related protein 1) shedding in a p38 MAPK-dependent manner. The apoER2 R952Q mouse model recapitulates characteristics observed in human disease. The underlying mechanism is that the apoER2 R952Q mutation in macrophages exacerbates VLDL-stimulated sLRP1 production in a p38 MAPK-dependent manner, resulting in its competition with cell surface LRP1 to impede triglyceride-rich lipoprotein clearance, thereby resulting in increased hypercholesterolemia and accelerated atherosclerosis.

Claudin2 is involved in the interaction between Megalocytivirus-induced virus-mock basement membrane (VMBM) and lymphatic endothelial cells

The genus Megalocytivirus, belonging to the family Iridoviridae, is one of the most detrimental virus groups to fish aquaculture. Megalocytivirus creates a virus-mock basement membrane (VMBM) on the surface of infected cells. This membrane provides attachment sites for lymphatic endothelial cells (LECs), disrupting fish's endothelial cell-extracellular matrix system. This disruption triggers injury to the vascular system and can result in death. Exploring the VMBM-cell interaction mechanism is crucial for uncovering the pathogenesis of Megalocytivirus and identifying therapeutic targets. Claudins, a class of tetra transmembrane proteins, play a key role in creating tight junctions between endothelial or epithelial cells. In this study, we demonstrated that the expression of Claudin2, a member of the Claudin family in fish, was significantly up-regulated by Megalocytivirus infection. Claudin2 was found in LECs attached to the surface of infected cells. It interacted with the VMBM viral components VP23R, VP08R, and VP33L at multiple binding sites through its two extracellular loops. However, it did not interact with the host basement membrane’s nidogen. Therefore, Claudin2 is involved in the interaction of LEC with VMBM and plays a role in the disturbed distribution of extracellular matrix and endothelial cells in Megalocytivirus-infected fish tissues. This study aims to uncover the molecular mechanisms by which Megalocytivirus infection leads to pathological changes in the vascular system.

Apoptosis: A Comprehensive Overview of Signaling Pathways, Morphological Changes, and Physiological Significance and Therapeutic Implications

Cell survival and death are intricately governed by apoptosis, a meticulously controlled programmed cell death. Apoptosis is vital in facilitating embryonic development and maintaining tissue homeostasis and immunological functioning. It is a complex interplay of intrinsic and extrinsic signaling pathways that ultimately converges on executing the apoptotic program. The extrinsic pathway is initiated by the binding of death ligands such as TNF-α and Fas to their respective receptors on the cell surface. In contrast, the intrinsic pathway leads to increased permeability of the outer mitochondrial membrane and the release of apoptogenic factors like cytochrome c, which is regulated by the Bcl-2 family of proteins. Once activated, these pathways lead to a cascade of biochemical events, including caspase activation, DNA fragmentation, and the dismantling of cellular components. Dysregulation of apoptosis is implicated in various disorders, such as cancer, autoimmune diseases, neurodegenerative disorders, and cardiovascular diseases. This article focuses on elucidating the molecular mechanisms underlying apoptosis regulation, to develop targeted therapeutic strategies. Modulating apoptotic pathways holds immense potential in cancer treatment, where promoting apoptosis in malignant cells could lead to tumor regression. This article demonstrates the therapeutic potential of targeting apoptosis, providing options for treating cancer and neurological illnesses. The safety and effectiveness of apoptosis-targeting drugs are being assessed in ongoing preclinical and clinical trials (phase I–III), opening the door for more effective therapeutic approaches and better patient outcomes.

Modifying the Glycocalyx of Melanoma Cells via Metabolic Glycoengineering Using N-Acetyl-d-glucosamine Analogues

Tumor cells are decorated with aberrant glycan structures on cell surfaces. It is well known that the glycocalyx serves as a main cellular regulator, although its role in cancer is still not completely understood. Over recent decades, several non-natural monosaccharides carrying clickable groups have been introduced in melanoma cells. This technique, called Metabolic Glycoengineering (MGE), opens up the possibility of altering the cell’s glycocalyx via click chemistry using a two-step approach. This study expands the field of MGE by showing the successful metabolic incorporation of novel alternative artificial glucosamine derivatives. The latter were either deoxygenated or blocked by methyl ether in position 4 to generate deficient glycosylation patterns, while being extended by an alkyne to enable click chemistry as a one-step approach. As a result, we observed a reduced proliferation rate of melanoma cells. Furthermore, using a lectin array, the decrease in high mannose epitopes was observed. In summary, the successful use of alternative artificial glucosamine derivatives enabled a significant alteration in the glycocalyx, consequently influencing cell behavior.

Hydrogen Sulfide‐Triggered Artificial DNAzyme Switches for Precise Manipulation of Cellular Functions

AbstractThe development of synthetic molecular tools responsive to biological cues is crucial for advancing targeted cellular regulation. A significant challenge is the regulation of cellular processes in response to gaseous signaling molecules such as hydrogen sulfide (H2S). To address this, we present the design of Gas signaling molecule‐Responsive Artificial DNAzyme‐based Switches (GRAS) to manipulate cellular functions via H2S‐sensitive synthetic DNAzymes. By incorporating stimuli‐responsive moieties to the phosphorothioate backbone, DNAzymes are strategically designed with H2S‐responsive azide groups at cofactor binding locations within the catalytic core region. These modifications enable their activation through H2S‐reducing decaging, thereby initiating substrate cleavage activity. Our approach allows for the flexible customization of various DNAzymes to regulate distinct cellular processes in diverse scenarios. Intracellularly, the enzymatic activity of GRAS promotes H2S‐induced cleavage of specific mRNA sequences, enabling targeted gene silencing and inducing apoptosis in cancer cells. Moreover, integrating GRAS with dynamic DNA assembly allows for grafting these functional switches onto cell surface receptors, facilitating H2S‐triggered receptor dimerization. This extracellular activation transmits signals intracellularly to regulate cellular behaviors such as migration and proliferation. Collectively, synthetic switches are capable of rewiring cellular functions in response to gaseous cues, offering a promising avenue for advanced targeted cellular engineering.

Deciphering transcriptome patterns in porcine mesenchymal stem cells promoting phenotypic maintenance and differentiation by key driver genes

Mesenchymal stem cells (MSC) are fibroblast-like non-hematopoietic cells with self-renewal and differentiation capacity, and thereby great potential in regeneration and wound healing. MSC populations are heterogeneous not only inherently, but also among different model species. In particular, porcine MSC serve as a frequently used resource for translational research, due to pigs’ distinctive closeness to human anatomy and physiology. However, information on gene expression profiles from porcine MSC and its dynamics during differentiation is sparse, especially with regard to cell surface and inner cell markers. In this study, we investigated the transcriptome of bone marrow-derived MSC and its differentiated cell types in a minipig breed for experimental research, known as Mini-LEWE, using bulk mRNA sequencing. Our data highlighted Rap1 signaling and downstream pathways PI3K-Akt and MAPK signaling as potential players for the maintenance of stemness of BM-MSC. In addition, we were able to link the process of differentiation to changes in the regulation of actin cytoskeleton. A total of 18 “BM-MSC differentiation driver markers” were identified, potentially promoting the process of differentiation into adipocytes, chondrocytes as well as osteocytes. Our results offer a new perspective on the molecular phenotype of porcine BM-MSC and the transcriptional responses in new differentiated progeny.

Single-cell multiomics analysis of chronic myeloid leukemia links cellular heterogeneity to therapy response.

The advent of tyrosine kinase inhibitors (TKIs) as treatment of chronic myeloid leukemia (CML) is a paradigm in molecularly targeted cancer therapy. Nonetheless, TKI-insensitive leukemia stem cells (LSCs) persist in most patients even after years of treatment and are imperative for disease progression as well as recurrence during treatment-free remission (TFR). Here, we have generated high-resolution single-cell multiomics maps from CML patients at diagnosis, retrospectively stratified by BCR::ABL1IS (%) following 12 months of TKI therapy. Simultaneous measurement of global gene expression profiles together with >40 surface markers from the same cells revealed that each patient harbored a unique composition of stem and progenitor cells at diagnosis. The patients with treatment failure after 12 months of therapy had a markedly higher abundance of molecularly defined primitive cells at diagnosis compared to the optimal responders. The multiomic feature landscape enabled visualization of the primitive fraction as a mixture of molecularly distinct BCR::ABL1+ LSCs and BCR::ABL1-hematopoietic stem cells (HSCs) in variable ratio across patients, and guided their prospective isolation by a combination of CD26 and CD35 cell surface markers. We for the first time show that BCR::ABL1+ LSCs and BCR::ABL1- HSCs can be distinctly separated as CD26+CD35- and CD26-CD35+, respectively. In addition, we found the ratio of LSC/HSC to be higher in patients with prospective treatment failure compared to optimal responders, at diagnosis as well as following 3 months of TKI therapy. Collectively, this data builds a framework for understanding therapy response and adapting treatment by devising strategies to extinguish or suppress TKI-insensitive LSCs.

Restored Collagen VI Microfilaments Network in the Extracellular Matrix of CRISPR-Edited Ullrich Congenital Muscular Dystrophy Fibroblasts

Collagen VI is an essential component of the extracellular matrix (ECM) composed by α1, α2 and α3 chains and encoded by COL6A1, COL6A2 and COL6A3 genes. Dominant negative pathogenic variants in COL6A genes result in defects in collagen VI protein and are implicated in the pathogenesis of muscular diseases, including Ullrich congenital muscular dystrophy (UCMD). Here, we designed a CRISPR genome editing strategy to tackle a dominant heterozygous deletion c.824_838del in exon 9 of the COL6A1 gene, causing a lack of secreted collagen VI in a patient’s dermal fibroblasts. The evaluation of efficiency and specificity of gene editing in treating patient’s fibroblasts revealed the 32% efficiency of editing the mutated allele but negligible editing of the wild-type allele. CRISPR-treated UCMD skin fibroblasts rescued the secretion of collagen VI in the ECM, which restored the ultrastructure of the collagen VI microfibril network. By using normal melanocytes as surrogates of muscle cells, we found that collagen VI secreted by the corrected patient’s skin fibroblasts recovered the anchorage to the cell surface, pointing to a functional improvement of the protein properties. These results support the application of the CRISPR editing approach to knock out COL6A1 mutated alleles and rescue the UCMD phenotype in patient-derived fibroblasts.

Integrin α2 in the microenvironment and the tumor compartment of digestive (gastrointestinal) cancers: emerging regulators and therapeutic opportunities

Integrins are a family of cell surface membrane receptors and play a crucial role in facilitating bidirectional cell signaling. Integrin α2 (ITGA2) is expressed across a range of cell types, including epithelial cells, platelets, megakaryocytes, and fibroblasts, where it functions as a surface marker and it is implicated in the cell movements. The most recent findings have indicated that ITAG2 has the potential to function as a novel regulatory factor in cancer, responsible for driving tumorigenesis, inducing chemoresistance, regulating genomic instability and remodeling tumor microenvironment. Hence, we primarily focus on elucidating the biological function and mechanism of ITGA2 within the digestive tumor microenvironment, while highlighting its prospective utilization as a therapeutic target for cancer therapy.

Isolation and assessment of probiotic potential of Acidipropionibacterium acidipropionici C03B-STR from goat milk with cholesterol-lowering capability.

Elevated levels of cholesterol or triglycerides in the blood are one of the major risk factors for coronary heart disease, which is the foremost leading cause of death across the world. The aims of this study were to isolate and verify the potential probiotic strain and cholesterol-lowering capability from goat milk. The C03B-STR isolate had a broad-spectrum antibacterial property and exhibited remarkable bacteriostatic activity against Klebsiella pneumoniae ATCC 13883 (27.00 ± 1.73mm), Pseudomonas aeruginosa ATCC 27853 (19.33 ± 0.57mm) and Staphylococcus aureus ATCC 10832 (19.00 ± 1.00mm) by agar well diffusion assay. This isolate is closely related to the 16S rDNA sequence of Acidipropionibacterium acidipropionici. Acidipropionibacterium acidipropionici C03B-STR can survive under acidic conditions (60.51 ± 0.02% of survival rate at pH 3.0 for 3h) and was as bile-tolerant strain (> 80% of survival rate at 0.30% bile salts after 3h of incubation). Furthermore, it showed significantly high cell surface hydrophobicity (74.36 ± 0.23%) and aggregation capability (> 83%) (p ≤ 0.05) but displayed low to moderate co-aggregation ability (44-61%). This strain can also be regarded as strongly adhesive (73.69 ± 0.74%) and inhibit pathogen attachment to the Caco-2 cell lines (39.20 ± 0.59-69.01 ± 0.29%). A. acidipropionici C03B-STR appeared to be safe (non-haemolytic) and controllable (sensitive to various antibiotics). Notably, it had the potential to suppress cholesterol uptake in Caco-2 cells (approximately 45%) and also reduced cholesterol level above 84% during the exponential phase under acidic conditions. Thus, A. acidipropionici C03B-STR from goat milk may be a promising novel potential cholesterol-lowering probiotic strain for application in functional foods and biotherapeutics.

Effect of NK cell receptor genetic variation on allogeneic stem cell transplantation outcome and in vitro NK cell cytotoxicity

Natural killer (NK) cells recognize and may kill malignant cells via their cell surface receptors. Killer cell immunoglobulin-like receptor (KIR) genotypes of donors have been reported to adjust the risk of relapse after allogeneic stem cell transplantation (HSCT), particularly in patients with acute myeloid leukemia. To test whether non-KIR NK cell receptors have a similar effect, we screened 1,638 genetic polymorphisms in 21 non-KIR NK cell receptor genes for their associations with relapse and graft-versus-host disease (GVHD) after HSCT in 1,491 HSCT donors (from Finland, the UK, Spain, and Poland), divided into a discovery and replication cohort. Eleven polymorphisms regulating or located in CD226, CD244, FCGR3A, KLRD1, NCR3, and PVRIG were associated with the risks for relapse and GVHD. These associations could not be confirmed in the replication cohort. Blood donor NK cells carrying alleles showing genetic protection for relapse had a higher in vitro NK cell killing activity than non-carriers whereas those with alleles genetically protective for GVHD had lower cytotoxicity, potentially indicating functional effects. Taken together, these results show no robust effects of genetic variation in the tested non-KIR NK cell receptors on the outcome of HSCT.