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U0126 is a potent and selective inhibitor of MEK1 and MEK2 kinases. It has been widely used as an inhibitor for the Ras/Raf/MEK/ERK signaling pathway with over 5000 references on the NCBI PubMed database. In particular,U0126 has been used in a number of studies to show that inhibition of the Raf/MEK/ERK pathway protects neuronal cells against oxidative stress. Here,we report that U0126 can function as an antioxidant that protects PC12 cells against a number of different oxidative-stress inducers. This protective effect of U0126 is independent of its function as a MEK inhibitor,as several other MEK inhibitors failed to show similar protective effects. U0126 reduces reactive oxygen species (ROS) in cells. We further demonstrate that U0126 is a direct ROS scavenger in vitro,and the oxidation products of U0126 exhibit fluorescence. Our finding that U0126 is a strong antioxidant signals caution for its future usage as a MEK inhibitor and for interpreting some previous results. View Publication

Manipulation of the CD28/CTLA-4 pathway is at the heart of a number of immunomodulatory approaches used in both autoimmunity and cancer. Although it is clear that CTLA-4 is a critical regulator of T cell responses,the immunological contexts in which CTLA-4 controls immune responses are not well defined. In this study,we show that whereas CD80/CD86-dependent activation of resting human T cells caused extensive T cell proliferation and robust CTLA-4 expression,in this context CTLA-4 blocking Abs had no impact on the response. In contrast,in settings where CTLA-4(+) cells were present as regulators� View Publication

UNLABELLED In the classical form of $\$1-antitrypsin deficiency (ATD),aberrant intracellular accumulation of misfolded mutant $\$1-antitrypsin Z (ATZ) in hepatocytes causes hepatic damage by a gain-of-function,proteotoxic" mechanism. Whereas some ATD patients develop severe liver disease (SLD) that necessitates liver transplantation� View Publication

Areas of a junction between two types of epithelia are known to be cancer-prone in many organ systems. However,mechanisms for preferential malignant transformation at the junction areas remain insufficiently elucidated. Here we report that inactivation of tumor suppressor genes Trp53 and Rb1 in the gastric squamous-columnar junction (SCJ) epithelium results in preferential formation of metastatic poorly differentiated neoplasms,which are similar to human gastroesophageal carcinoma. Unlike transformation-resistant antral cells,SCJ cells contain a highly proliferative pool of immature Lgr5-CD44+ cells,which are prone to transformation in organoid assays,comprise early dysplastic lesions,and constitute up to 30{\%} of all neoplastic cells. CD44 ligand osteopontin (OPN) is preferentially expressed in and promotes organoid formation ability and transformation of the SCJ glandular epithelium. OPN and CD44 overexpression correlate with the worst prognosis of human gastroesophageal carcinoma. Thus,detection and selective targeting of the active OPN-CD44 pathway may have direct clinical relevance. View Publication

As the prognosis of invasive aspergillosis remains unacceptably poor in patients undergoing hematopoietic stem cell transplantation (HSCT),there is a growing interest in the adoptive transfer of antifungal effector cells,such as Natural Killer (NK) cells. Because immunosuppressive agents are required in most HSCT recipients,knowledge of the impact of these compounds on the antifungal activity of NK cells is a prerequisite for clinical trials. We,therefore,assessed the effect of methylprednisolone (mPRED),cyclosporin A (CsA) and mycophenolic acid (MPA) at different concentrations on proliferation,apoptosis/necrosis,and the direct and indirect anti-Aspergillus activity of human NK cells. Methylprednisolone decreased proliferation and increased apoptosis of NK cells in a significant manner. After seven days,a reduction of viable NK cells was seen for all three immunosuppressants,which was significant for MPA only. Cyclosporin A significantly inhibited the direct hyphal damage by NK cells in a dose-dependent manner. None of the immunosuppressive compounds had a major impact on the measured levels of interferon-$\gamma$,granulocyte-macrophage colony-stimulating factor and RANTES (regulated on activation,normal T cell expressed and secreted; CCL5). Our data demonstrate that commonly used immunosuppressive compounds have distinct effects on proliferation,viability and antifungal activity of human NK cells,which should be considered in designing studies on the use of NK cells for adoptive antifungal immunotherapy. View Publication

Autoimmune uveitis is a leading cause of severe vision loss,and animal models provide unique opportunities for studying its pathogenesis and therapeutic strategies. Here we employ scRNA-seq,RNA-seq and various molecular and cellular approaches to characterize mouse models of classical experimental autoimmune uveitis (EAU),revealing that EAU causes broad retinal neuron degeneration and marker downregulation,and that Müller glia may act as antigen-presenting cells. Moreover,EAU immune response is primarily driven by Th1 cells,and results in dramatic upregulation of CC chemokines,especially CCL5,in the EAU retina. Accordingly,overexpression of CCR5,a CCL5 receptor,in mesenchymal stem cells (MSCs) enhances their homing capacity and improves their immunomodulatory outcomes in preventing EAU,by reducing infiltrating T cells and activated microglia and suppressing Nlrp3 inflammasome activation. Taken together,our data not only provide valuable insights into the molecular characteristics of EAU but also open an avenue for innovative MSC-based therapy.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12974-024-03134-3. View Publication

In this study,Chen et al. describe two independent mechanisms that control ?-catenin levels in neuroglial cells and drive their proliferation. The work provides mechanistic insight into the impact of MEK activation resulting from the biallelic loss of NF1 or BRAF rearrangement in pediatric gliomas. The two major genomic alterations in pediatric pilocytic astrocytoma (PA) are NF1 loss and KIAA1549:BRAF rearrangement. Although these molecular changes result in increased MEK activity and tumor growth,it is not clear exactly how MEK controls human neuroglial cell proliferation. Leveraging human-induced pluripotent stem cells harboring these PA-associated alterations,we used a combination of genetic and pharmacological approaches to demonstrate that MEK-regulated cell growth is mediated by ?-catenin through independent mechanisms involving IRX2 control of CTNNB1 transcription and NPTX1 stabilization of ?-catenin protein levels. These results provide new mechanistic insights into MEK regulation of human brain cell function. View Publication

The persistence of HIV-1 latency reservoirs in CD4+ T cells is a significant obstacle for curing HIV-1. Shock-and-kill strategies,which aim to reactivate latent HIV-1 followed by cytotoxic clearance,have shown limited success in vivo due to insufficient efficacy of latency reversal agents (LRAs) and off-target effects. Natural killer (NK) cells,with their ability to mediate cytotoxicity independent of antigen specificity,offer a promising avenue for enhancing the shock-and-kill approach. Previously,we observed that pan-caspase inhibitors induce NK cells to secrete an LRA in vitro. Here,we aimed to identify this LRA using a targeted proteomic approach. We identified lymphotoxin-α (LTα) as the key LRA secreted by NK cells following pan-caspase inhibitor treatment. LTα was shown to significantly induce HIV-1 LTR promoter activity,a hallmark of viral reactivation. Neutralization of LTα effectively abolished the observed LRA activity,confirming its central role. Moreover,cytokine-primed but not resting human primary NK cells exhibited LRA activity that could be neutralized with LTα neutralizing antibodies. Finally,pan-caspase inhibitor treatment did not decrease the ability of the cytokine-primed NK cells to kill target cells. These findings demonstrate that cytokine-primed NK cells,through LTα secretion,can effectively reactivate latent HIV-1 following pan-caspase inhibitor treatment,without compromising NK cell cytotoxicity. This highlights a potential enhancement strategy utilizing NK cells for shock-and-kill approaches in HIV-1 cure research. View Publication

BackgroundLevels of the human cationic antimicrobial host defence peptide LL-37 are enhanced in the lungs during neutrophilic airway inflammation. LL-37 drives Th17 differentiation,and Th17 cells produce IL-17A and IL-17F which form the biologically active heterodimer IL-17A/F. While IL-17 is a critical mediator of neutrophilic airway inflammation,LL-37 exhibits contradictory functions; LL-37 can both promote and mitigate neutrophil recruitment depending on the inflammatory milieu. The impact of LL-37 on IL-17-induced responses in the context of airway inflammation remains largely unknown. Therefore,we examined signaling intermediates and downstream responses mediated by the interplay of IL-17A/F and LL-37 in human bronchial epithelial cells (HBEC). As LL-37 can become citrullinated during airway inflammation,we also examined LL-37-mediated downstream responses compared to that with citrullinated LL-37 (citLL-37) in HBEC.ResultsUsing an aptamer-based proteomics approach,we identified proteins that are altered in response to IL-17A/F in HBEC. Proteins enhanced in response to IL-17A/F were primarily neutrophil chemoattractants,including chemokines and proteins associated with neutrophil migration such as lipocalin-2 (LCN-2). We showed that selective depletion of LCN-2 mitigates neutrophil migration,functionally demonstrating LCN-2 as a critical neutrophil chemoattractant. We further demonstrated that LL-37 and citLL-37 selectively suppress IL-17A/F-induced LCN-2 abundance in HBEC. Mechanistic studies revealed that LL-37 and citLL-37 suppresses IL-17 A/F-mediated enhancement of C/EBPβ,a transcription factor required for LCN-2 production. In contrast,LL-37 and citLL-37 enhance the abundance of ribonuclease Regnase-1,which is a negative regulator of IL-17 and LCN-2 in HBEC. In an animal model of allergen-challenged airway inflammation with elevated IL-17A/F and neutrophil elastase in the lungs,we demonstrated that CRAMP (mouse orthologue of LL-37) negatively correlates with LCN-2.ConclusionsOverall,our findings showed that LL-37 and citLL-37 can selectively suppress the abundance of IL-17A/F-mediated LCN-2,a protein that is critical for neutrophil migration in HBEC. These results suggest that LL-37,and its modified citrullinated form,have the potential to negatively regulate IL-17-mediated neutrophil migration during airway inflammation. To our knowledge,this is the first study to report that the immunomodulatory function of LL-37 enhances the RNA binding protein Regnase-1,suggesting that a post-transcriptional mechanism of action is mediated by the peptide.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12950-025-00446-w. View Publication

Neurodevelopmental studies employing animal models encounter challenges due to interspecies differences and ethical concerns. Maturing neurons of human origin,undergoing several developmental stages,present a powerful alternative. In this study,human embryonic stem cell (H9 cell line) was differentiated into neural stem cells and subsequently matured into neurons over 30 days. Ion AmpliSeq™ was used for transcriptomic characterization of human stem cell-derived neurons at multiple time points. Data analysis revealed a progressive increase of markers associated with neuronal development and astrocyte markers,indicating the establishment of a co-culture accommodating both glial and neurons. Transcriptomic and pathway enrichment analysis also revealed a more pronounced GABAergic phenotype in the neurons,signifying their specialization toward this cell type. The findings confirm the robustness of these cells across different passages and demonstrate detailed progression through stages of development. The model is intended for neurodevelopmental applications and can be adapted to investigate how genetic modifications or exposure to chemicals,pharmaceuticals,and other environmental factors influence neurons and glial maturation. View Publication