Search Results (232)

This paper conducts a literature review on the role of natural killer cells in haploidentical hematopoietic stem cell transplantation. Theoretical concepts related to KIR genes are introduced regarding their structure, nomenclature, genetic organization, polymorphism, and inheritance pattern, types of KIR proteins and receptors, HLA ligands for KIR receptors, and the definition of different NK alloreactivity prediction models for the donor of haploidentical hematopoietic stem cell transplantation and the recipient. These models include the following and consider incompatibility: ligand–ligand, receptor–ligand, gene–gene, and KIR haplotype models or the KIR-B donor group. These models consider the presence or absence of specific ligands or receptors and/or KIR genes in the donor and recipient to predict alloreactivity. Determining the best model for predicting KIR alloreactivity and its significance in donor selection algorithms for haploidentical transplantation is still under investigation. Full article

The function of NK cells in cancer and viral infections is well documented and understood. NK cell activity, including cytokine secretion, cytotoxic activity, and the coordination of inhibitory and activating receptors, linking innate and adaptive immunity, among others, has been examined for numerous pathogens, including parasites, bacteria, and viruses. The emergence of the SARS-CoV-2 health crisis has exposed a deficiency in understanding the previously elucidated mechanisms; the rationale for the reported variability in symptomatology among COVID-19 patients is extensive and intricate. It is evident that NK cells exert a significant influence on symptom severity, and their absence, with the presence or absence of their surface receptors, elicits a tailored response to the virus. This overview examines the impact of NK cells on the progression of several viral diseases, emphasizing their involvement in the pathogenesis of SARS-CoV-2 via the activation of surface receptors. Full article

Chimeric antigen receptor (CAR)-engineered natural killer (NK) cells are a promising platform for off-the-shelf immunotherapy due to their safety advantages over CAR-T cells, including lower risk of graft-versus-host disease, cytokine release syndrome, and neurotoxicity. However, their persistence and efficacy are limited by immunological challenges such as host T-cell-mediated rejection, NK cell fratricide, and macrophage-mediated clearance. This review summarizes gene editing strategies to overcome these barriers, including β2-microglobulin (B2M) knockout and HLA-E overexpression to evade T and NK cell attacks, CD47 overexpression to inhibit phagocytosis, and TIGIT deletion to enhance cytotoxicity. In addition, we discuss functional enhancements such as IL-15 pathway activation, KIR modulation, and transcriptional reprogramming (e.g., FOXO1 knockout) to improve persistence and antitumor activity. We also highlight the role of induced pluripotent stem cell (iPSC)-derived NK platforms, enabling standardized, scalable, and multiplex gene-edited products. Finally, we explore artificial intelligence (AI) applications in immunogenomic profiling and predictive editing to tailor NK cell therapies to patient-specific HLA/KIR/SIRPα contexts. By integrating immune evasion, functional reinforcement, and computational design, we propose a unified roadmap for next-generation CAR-NK development, supporting durable and broadly applicable cell-based therapies. Full article

Maternal–fetal tolerance mechanisms are crucial during human pregnancy to prevent the immune rejection of the embryo. A well-known mechanism blocking NK-cell cytotoxicity is the interaction of their inhibitory killer-cell immunoglobulin-like receptors (iKIR) with HLA-C molecules on the target cells. In this study, we aimed to investigate the expression of iKIRs (KIR2DL1 and KIR2DL2/3) on the matched decidual and peripheral γδT cells and the localization of HLA-C ligands throughout human pregnancy. The degranulation of γδT cells of pregnant and non-pregnant women in the presence of trophoblast cells was evaluated as well. Our results showed a higher proportion of iKIR-positive γδT cells at the maternal–fetal interface early in human pregnancy compared to the paired blood of pregnant women and full-term pregnancy decidua. In accordance, HLA-C was intensively expressed by the intermediate cytotrophoblasts and decidua-invading extravillous trophoblasts (EVTs) in early but not late pregnancy. Decidual γδT cells during early pregnancy showed higher spontaneous degranulation compared to their blood pairs, but neither decidual nor peripheral γδ T cells increased their degranulation in the presence of Sw71 EVT-like cells. The latter were unable to suppress the higher cytotoxicity of γδT cells, suggesting a complex regulatory landscape beyond NK-like activity inhibition. Full article

Killer Ig-like Receptors (KIRs) regulate immune responses, maintaining the balance between activation and inhibition of the immune system. KIRs are expressed on natural killer cells and some CD8 T cells and interact with HLA class I molecules, influencing various physiological and pathological processes. KIRs’ polymorphism creates a variability in immune responses among individuals. KIRs are involved in autoimmune disorders, cancer, infections, neurological diseases, and other diseases. Specific combinations of KIRs and HLA are linked to several diseases’ susceptibility, progression, and outcomes. In particular, the balance between inhibitory and activating KIRs can determine how the immune system responds to pathogens and tumors. An imbalance can lead to an excessive response, contributing to autoimmune diseases, or an inadequate response, allowing immune evasion by pathogens or cancer cells. The increasing number of studies on KIRs highlights their essential role as diagnostic and prognostic biomarkers and potential therapeutic targets. This review provides a comprehensive overview of the role of KIRs in all clinical conditions and diseases, listed alphabetically, where they are analyzed. Full article

Cell lines and their corresponding expression plasmids are extensively utilized in the study of insect physiology and pathology. In this research, four single-cell cultured lines (Px4-1 to Px4-4) of Plutella xylostella were established from eggs. The promoter for the P. xylostella elongation factor 1α (PxEF1α), known for its high driving activity in cells, was cloned and used to construct expression plasmids. Dual-luciferase activity assays and EGFP expression analyses demonstrated that the PxEF1α promoter exhibited the strongest driving activity in Px4-2 cells, comparable to that of the immediate-early 1 promoter associated with the homologous region 5 enhancer (AcIE1^hr5) from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). In contrast, the driving activity of PxEF1α in cells derived from Spodoptera frugiperda, Trichoplusia ni, and Helicoverpa armigera was lower. Furthermore, the PxEF1α promoter was successfully employed to drive inward rectifier potassium 2A (Kir2A) expression in Px4-2 cells. The electrophysiological properties of the insect Kir2A channel were successfully characterized for the first time. It was observed that the PxKir2A channel possesses typical inward rectifier potassium channel properties and can be inhibited by nanomolar concentrations of VU625 and VU590. This study offers a novel approach for the expression and investigation of foreign gene function in insect cells and provides a valuable tool for the in-depth study of key biomolecules in P. xylostella. Full article

Tolerance to foetal tissues in pregnancy depends on the match between mother and child. CD4+Foxp3+ regulatory T cells (Tregs), which are involved in peripheral tolerance, may facilitate this effect. Previous findings have indicated that the number of missing KIR ligands (MSLs) between mother and child correlates with the risk of gestational hypertension (GH) and preeclampsia (PE). This study tested whether Tregs are involved in the pathogenesis of gestational disorders. In total, 57 pregnant women participated, including 39 with hypertensive disorders of pregnancy and 18 healthy controls. Treg phenotypes were evaluated using multicolour flow cytometry. Killer cell immunoglobulin-like receptors (KIRs) and their ligands were assessed using NGS and PCR-SSO typing. The correlation between the MSLs and Treg antigen expression was evaluated. The pregnancy-related hypertensive groups differ from the healthy control group in the frequency of particular Treg subsets. However, there was a correlation between an increasing number of MSLs and only one subset of Tregs, which was PD-1+ Tregs. Surprisingly, women suffering from GH or PE had a significantly higher percentage of PD-1+ Tregs than healthy pregnant women. The percentages of several other populations of Tregs, such as those expressing CCR4, CCR10, CD39, and CD73, were higher in healthy pregnant women than in those with GH or PE, but these numbers did not correlate with MSLs. The exhausted PD-1+ Treg cell subsets may play a crucial role in the pathogenesis of hypertensive disorders of pregnancy. It is also hypothesised that MSLrelated mechanisms trigger PD-1+ Treg expansion, but their increased number fails to provide protection against hypertensive conditions of pregnancy. Full article

Metabolic stress on the heart can cause dilation of coronary arterioles for blood flow recruitment. Although potassium ions (K⁺) released from the myocardium are a major mediator for this response, the underlying signaling pathways for vasodilation are incompletely understood. Herein, the roles of smooth muscle inward-rectifier K⁺ channel subtype 2.1 (K_ir2.1) and Na⁺/K⁺-ATPase were examined. Porcine coronary arterioles were isolated, cannulated, and pressurized for vasomotor study. Vessels developed basal tone and dilated concentration-dependently to extraluminal K⁺ from 7 to 20 mM. Higher K⁺ concentrations (25–40 mM) caused graded vasoconstriction. Vasodilation to K⁺ (10 mM) was not altered by endothelial removal, and blockade of ATP-sensitive K⁺ channels, voltage-sensitive K⁺ channels, or calcium-activated K⁺ channels did not affect K⁺-induced vasodilation. However, sustained but not abrupt transient vasodilation to K⁺ was reduced by the nonspecific K_ir channel inhibitor Ba²⁺ or K_ir2.1 channel blocker chloroethylclonidine. The Na⁺/K⁺-ATPase inhibitor ouabain attenuated K⁺-elicited vasodilation, and ouabain with Ba²⁺ abolished the response. Transfection of arterioles with K_ir2.1 antisense oligonucleotides abolished sustained but not transient dilation. It is concluded that extraluminal K⁺ elevation within the physiological range induces initial transient dilation of porcine coronary arterioles by activating smooth muscle Na⁺/K⁺-ATPase and sustained dilation via smooth muscle K_ir2.1 channels. Full article

Precisely localizing the spatial distribution of proteins within various brain cell types and subcellular compartments, such as the synapses, is essential for generating and testing hypotheses to elucidate their roles in brain function. While the fms-like tyrosine kinase-3 (Flt3) has been extensively studied in the context of blood cell development and leukemia pathogenesis, its role in the brain remains poorly understood. Previous efforts to address this issue were hindered by the low expression levels of Flt3 and the limited sensitivity of the standard immunolabeling method, which were insufficient to reliably detect Flt3 protein in brain tissue. In this study, we systematically characterized Flt3 protein localization during brain development using a highly sensitive immunolabeling method based on alkaline phosphatase (AP) polymer biochemistry. This approach revealed a previously unrecognized neuron-selective Flt3 expression pattern in both mouse and human cerebella, with a developmental increase in total protein levels accompanied by a shift from a cytosolic to a dendritic subcellular distribution. Combining AP-polymer-based immunohistochemistry (AP-IHC) for Flt3 with conventional immunostaining of cell type marker proteins revealed parvalbumin- and calbindin-positive Purkinje cells to be the main cell type expressing Flt3 in the cerebellum. To validate the versatility of the AP-IHC method for detecting low-abundance neuronal proteins, we demonstrated robust labeling of Kir2.1, a potassium channel protein, in brain tissue sections from mouse, pig, and human samples. We further applied the AP-IHC method to human stem cell-derived neurons, effectively visualizing the postsynaptic density scaffold protein PSD95 within synapses. To our knowledge, this is the first study to employ an AP-IHC method combined with other standard immunofluorescent staining to co-detect weakly expressed neuronal proteins and other cellular markers in brain tissue and cultured neurons. Additionally, our findings uncover a previously unrecognized neuron-specific pattern of Flt3 expression in the cerebellum, laying the foundation for future mechanistic studies on its role in normal brain development and neurological disorders. Full article

Background: Neonatal diabetes (NDM) is a rare genetic disorder diagnosed in infants under six months of age, characterized by persistent hyperglycemia resulting from insufficient or absent insulin production. Unlike the more common forms of diabetes, such as type 1 diabetes (T1D) and type 2 diabetes (T2D), NDM is predominantly caused by monogenic mutations affecting ATP-sensitive potassium (K-ATP) channels in pancreatic beta cells. The most common mutations involved in NDM are found in the KCNJ11 and ABCC8 genes, which encode the Kir6.2 and SUR1 subunits of the K-ATP channel, respectively. These mutations prevent normal insulin secretion by disrupting the function of the K-ATP channel. While genetic advances have identified about 40 genes implicated in NDM, the KCNJ11 and ABCC8 mutations are most commonly seen. Methods: This review provides a comprehensive exploration of the genetic basis, clinical presentation, and treatment strategies for NDM including the role of sulfonylureas, which have revolutionized the management of this condition. Furthermore, it presents a detailed case study of an infant diagnosed with an ABCC8 mutation, illustrating the pivotal role of genetic testing in guiding clinical decisions. Conclusions: Finally, the article discusses challenges in management, such as the persistence of neurological impairments, and outlines potential directions for future research including genetic therapies and prenatal diagnosis. Full article

Chronic pain and mental health disorders, such as depression and anxiety, frequently co-occur and share underlying mechanisms involving neuronal excitability and synaptic transmission. The inwardly rectifying potassium channel 4.1 (Kir4.1), predominantly expressed in glial cells, is crucial for maintaining extracellular potassium and glutamate homeostasis. Dysregulation of Kir4.1 leads to altered neuronal activity, contributing to both chronic pain and mental health disorders. In chronic pain, downregulation of Kir4.1 impairs potassium buffering and glutamate clearance, increasing neuronal excitability and enhancing pain signaling through peripheral and central sensitization. In mental health disorders, impaired Kir4.1 function disrupts neurotrophic factor secretion and neuroinflammatory pathways, leading to mood disturbances. This review primarily summarizes findings from preclinical studies to examine the relationship between Kir4.1 and the pathogenesis of chronic pain and mental health disorders, discussing its molecular structure, expression patterns, and functional roles. Furthermore, we explore therapeutic strategies targeting Kir4.1, including pharmacological modulators and gene therapy approaches, emphasizing its potential as a novel therapeutic target. Full article

Inwardly rectifying potassium (Kir) channels regulate essential physiological processes in insects and have been identified as potential targets for developing new insecticides. Flonicamid has been reported to inhibit Kir channels, disrupting the functions of salivary glands and renal tubules. However, the precise molecular target of flonicamid remains debated. It is unclear whether flonicamid directly targets Kir channels or acts on other sites involved in the activation of transient receptor potential vanilloid (TRPV) channels. In this study, we observed that flonicamid is more toxic to flies than its metabolite, flumetnicam. This higher toxicity is difficult to reconcile if nicotinamidase is the active target, as flonicamid does not inhibit nicotinamidase. An alternative explanation is that flonicamid and flumetnicam may have distinct targets or act on multiple targets. Furthermore, reducing the expression of three individual Kir genes in the salivary glands of D. melanogaster significantly decreased the flies’ susceptibility to both flonicamid and flumetnicam. The double knockdown of Kir1 with Kir3 or Kir2 with Kir3 further reduced the flies’ sensitivity to both compounds. These findings confirm the involvement of Kir channels in mediating the toxic effects of flonicamid on flies. Overall, this study offers new insights into the physiological roles of insect Kir channels and flonicamid toxicity. Full article

Background: Immunotherapy is gaining great relevance in both non-muscle-invasive bladder cancer (NMIBC), with the use of bacille Calmette–Guerin (BCG), and in muscle-invasive BC (MIBC) with anti-checkpoint therapies blocking PD-1/PD-L1, CTLA-4/CD80-CD86, and, more recently, NKG2A/HLA-E interactions. Biomarkers are necessary to optimize the use of these therapies. Methods: We evaluated killer-cell immunoglobulin-like receptors (KIRs) and HLA-I genotyping and the expression of NK cell receptors in circulating T and NK lymphocytes at diagnosis in 325 consecutive BC patients (151 treated with BCG and 174 treated with other therapies), as well as in 648 patients with other cancers and 973 healthy donors as controls. The proliferation and production of cytokines and cytotoxicity were evaluated in peripheral blood mononuclear cells, stimulated in vitro with anti-CD3/CD28 or BCG, from selected patients based on HLA-B −21M/T dimorphism (NKG2A ligands). Results: The HLA-B −21M/T genotype showed opposing results in BC patients treated with BCG or other therapies. The MM genotype, compared to MT and TT, was associated with a longer 75th-percentile overall survival (not reached vs. 68.0 ± 13.7 and 52.0 ± 8.3 months, p = 0.034) in BCG, but a shorter (8.0 ± 2.4 vs. 21.0 ± 3.4 and 19.0 ± 4.9 months, p = 0.131) survival in other treatments. The HLA-B −21M/T genotype was an independent predictive parameter of the progression-free survival (HR = 2.08, p = 0.01) and the OS (HR = 2.059, p = 0.039) of BC patients treated with BCG, together with age and tumor histopathologic characteristics. The MM genotype was associated with higher counts of circulating CD56^bright, fewer KIR2DL1/L2⁺ NK cells, and lower NKG2A expression, but not with differential in vitro NK cell functionality. Conclusions: The HLA-B −21M/T is independently associated with BC patient outcomes and can help to optimize the use of new immunotherapies in these patients. Full article

Amniotic fluid is a complex and dynamic biological matrix that surrounds the fetus during the pregnancy. From this fluid, is possible to isolate various cell types with particular interest directed towards stem cells (AF-SCs). These cells are highly appealing due to their numerous potential applications in the field of regenerative medicine for tissues and organs as well as for treating conditions such as traumatic or ischemic injuries to the nervous system, myocardial infarction, or cancer. AF-SCs, when subcultured in the presence of basic Fibroblast Growth Factor (bFGF), have been shown to survive and migrate when transplanted into the striatum of the rat brain, exhibiting behavior characteristics of neuronal/glial progenitor cells. In this work, we performed an electrophysiological characterization to ascertain the propensity of AF-SCs to differentiate into glial and neuronal cells by bFGF. By using patch clamp technique we characterized a fibroblast-like morphology that display a barium-sensitive inward-rectifying potassium current (Kir) and calcium-activated potassium currents (KCa). The electrophysiological and calcium dynamics of histamine, a marker of undifferentiated neural progenitors, was further studied. Histamine promoted intracellular calcium increase by Fura-2 recording and calcium-activated potassium current activation with a similar temporal profile in AF-SC. The data presented in this paper ultimately confirm the expression in AF-SCs of the Kir and KCa currents, also showing regulation by endogenous stimuli such as histamine for the latter. Full article