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Biliverdin IXβ reductase (BLVRB) is an NADPH-dependent enzyme previously implicated in a redox-regulated mechanism of thrombopoiesis distinct from the thrombopoietin (TPO)/c-MPL axis. Here, we apply computational modeling to inform molecule design, followed by de novo syntheses and screening of unique small molecules retaining the capacity for selective BLVRB inhibition as a novel platelet-enhancing strategy. Two distinct classes of molecules are identified, and NMR spectroscopy and co-crystallization studies confirm binding modes within the BLVRB active site and ring stacking between the nicotinamide moiety of the NADP + cofactor. A diazabicyclo derivative displaying minimal off-target promiscuity and excellent bioavailability characteristics promotes megakaryocyte speciation in biphenotypic (erythro/megakaryocyte) cellular models and synergizes with TPO-dependent megakaryocyte formation in hematopoietic stem cells. Upon oral delivery into mice, this inhibitor expands platelet recovery in stress thrombopoietic models with no adverse effects. In this work, we identify and validate a cellular redox inhibitor retaining the potential to selectively promote megakaryocytopoiesis and enhance stress-associated platelet formation in vivo distinct from TPO receptor agonists. Subject terms: Target validation, Medicinal chemistry, X-ray crystallography, Computational biophysics

Osteoporosis diagnoses are increasing in the ageing population, and although some treatments exist, these have several disadvantages, highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts, which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here, we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1), a transcription factor that is essential for osteoclast differentiation, and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control, and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2, FFAR4, FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity, and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells, reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies.

Lipid dyshomeostasis and tau pathology are present in frontotemporal lobar degeneration (FTLD) and Alzheimer’s disease (AD). However, the relationship between lipid dyshomeostasis and tau pathology remains unclear. We report that GRAM Domain Containing 1B (GRAMD1B), a nonvesicular cholesterol transporter, is increased in excitatory neurons of human neural organoids (HNOs) with the MAPT R406W mutation. Human FTLD, AD cases, and PS19 tau mice also have increased GRAMD1B expression. We show that overexpression of GRAMD1B increases levels of free cholesterol, lipid droplets, and impairs autophagy flux. Modulating GRAMD1B in iPSC-derived neurons also alters key autophagy-related components such as PI3K, phospho-AKT, and p62, as well as phosphorylated tau, and CDK5R1. Blocking GRAMD1B function decreases free cholesterol and lipid droplets. Knocking down GRAMD1B additionally reduces phosphorylated tau, and CDK5R1 expression. Our findings elucidate the role of GRAMD1B in the nervous system and highlight its relevance to FTLD and AD. Subject terms: Diseases of the nervous system, Ageing

Myelodysplastic syndrome (MDS) is a malignant hematologic disorder with limited curative options, primarily reliant on hematopoietic stem cell transplantation. Anemia, a prevalent symptom of MDS, has few effective treatment strategies. Realgar, though known for its therapeutic effects on MDS, remains poorly understood in terms of its mechanism of action. In this study, both in vivo and in vitro experiments were conducted using Realgar and its primary active component, As 2 S 2 , to examine their impact on mouse erythroblasts at the single-cell level. Realgar treatment significantly altered the transcriptional profiles and cellular composition of bone marrow in mice, both in vivo and in vitro. Differentially expressed genes in erythroblasts regulated by Realgar were identified, unveiling potential regulatory functions and signaling pathways, such as heme biosynthesis, hemoglobin production, oxygen binding, IL-17 signaling, and MAPK pathways. These findings suggest that Realgar enhances the differentiation of erythroblasts in mouse bone marrow and improves overall blood cell counts. This work offers preliminary insights into Realgar’s mechanisms, expands the understanding of this mineral medicine, and may inform strategies to optimize its therapeutic potential in hematologic diseases. The online version contains supplementary material available at 10.1186/s12935-025-03768-0.

Brain decellularized extracellular matrix (ECM) can be an attractive scaffold capable of mimicking the native ecosystem of the central nervous system tissue. We studied the in vitro response of neural cultures exposed to region-specific brain decellularized ECM scaffolds from three distinct neuroanatomical sections: cortex, cerebellum and remaining areas. First, each brain region was evaluated with the isotropic fractionator method to understand the cellular composition of the different cerebral areas. Second, the cerebral regions were subjected to the decellularization process and their respective characterization using molecular, histological, and ultrastructural techniques. Third, the levels of neurotrophic factors in the decellularized brain scaffold were analyzed. Fourth, we studied the region-specific brain decellularized ECM as a mimetic platform for the maturation of PC12 cells, as a unidirectional model of differentiation. Finally, in vitro studies were carried out to evaluate the cell recovery capacity of brain decellularized ECM under stroke-mimetic conditions. Our results show that region-specific brain decellularized ECM can serve as a biomimetic scaffold capable of promoting the growth of neural lineage cells and, in addition, it possesses a combination of structural and biochemical signals (e.g., neurotrophic factors) that are capable of inducing cell phenotypic changes and promote viability and cell recovery in a stroke/ischemia model in vitro. The online version contains supplementary material available at 10.1038/s41598-025-95656-w.

Genetically encoded calcium ion (Ca 2+ ) indicators (GECIs) are widely-used molecular tools for functional imaging of Ca 2+ dynamics and neuronal activities with single-cell resolution. Here we report the design and development of two far-red fluorescent GECIs, FR-GECO1a and FR-GECO1c, based on the monomeric far-red fluorescent proteins mKelly1 and mKelly2. FR-GECOs have excitation and emission maxima at ~596 nm and ~644 nm, respectively, display large responses to Ca 2+ in vitro (Δ F / F 0 = 6 for FR-GECO1a, 18 for FR-GECO1c), are bright under both one-photon and two-photon illumination, and have high affinities (apparent K d = 29 nM for FR-GECO1a, 83 nM for FR-GECO1c) for Ca 2+ . FR-GECOs offer sensitive and fast detection of single action potentials in neurons, and enable in vivo all-optical manipulation and measurement of cellular activities in combination with optogenetic actuators. Subject terms: Fluorescent proteins, Optogenetics, Zebrafish, Molecular neuroscience, Calcium signalling

The lymph node (LN) performs essential roles in immunosurveillance throughout the body. Developing in vitro models of this key tissue is of great importance to enhancing physiological relevance in immunoengineering. The LN consists of stromal populations and immune cells, which are highly organized and bathed in constant interstitial fluid flow (IFF). The stroma, notably the fibroblastic reticular cells (FRCs) and the lymphatic endothelial cells (LECs), play crucial roles in guiding T cell migration and are known to be sensitive to fluid flow. During inflammation, interstitial fluid flow rates drastically increase in the LN. It is unknown how these altered flow rates impact crosstalk and cell behavior in the LN, and most existing in vitro models focus on the interactions between T cells, B cells, and dendritic cells rather than with the stroma. To address this gap, we developed a human engineered model of the LN stroma consisting of FRC-laden hydrogel above a monolayer of LECs in a tissue culture insert with gravity-driven interstitial flow. We found that FRCs had enhanced coverage and proliferation in response to high flow rates, while LECs experienced decreased barrier integrity. We added CD4+ and CD8+ T cells and found that their egress was significantly decreased in the presence of interstitial flow, regardless of magnitude. Interestingly, 3.0 μ m/s flow, but not 0.8 μ m/s flow, correlated with enhanced inflammatory cytokine secretion in the LN stroma. Overall, we demonstrate that interstitial flow is an essential consideration in the lymph node for modulating LN stroma morphology, T cell migration, and inflammation.

Studying ciliary genes in the context of the human central nervous system is crucial for understanding the underlying causes of neurodevelopmental ciliopathies. Here, we use pluripotent stem cell-derived spinal organoids to reveal distinct functions of the ciliopathy gene RPGRIP1L in humans and mice, and uncover an unexplored role for cilia in human axial patterning. Previous research has emphasized Rpgrip1l critical functions in mouse brain and spinal cord development through the regulation of SHH/GLI pathway. Here, we show that RPGRIP1L is not required for SHH activation or motoneuron lineage commitment in human spinal progenitors and that this feature is shared by another ciliopathy gene, TMEM67 . Furthermore, human RPGRIP1L -mutant motoneurons adopt hindbrain and cervical identities instead of caudal brachial identity. Temporal transcriptome analysis reveals that this antero-posterior patterning defect originates in early axial progenitors and correlates with cilia loss. These findings provide important insights into the role of cilia in human neural development. Subject terms: Ciliogenesis, Pattern formation, Pluripotent stem cells, Neurogenesis

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. We previously discovered that heme oxygenase 1 (HO1) is crucial for chemoresistance in AML, but the detailed molecular mechanism of that remains unclear. RNA sequencing was conducted to assess transcriptomic changes in three pairs of AML cells after regulating the expression of HO1. The molecular mechanism by which HO1 induces gilteritinib resistance in FLT3-ITD (FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD)) AML was evaluated by quantitative real-time PCR (qRT-PCR), CCK-8, flow cytometry, and western blotting. FLT3-ITD AML mouse models were established to investigate the effects of HO1 expression on gilteritinib resistance in vivo. In these three pairs of AML cells, we discovered that HO1-mediated drug resistance is connected to the interleukin-4-mediated signaling pathway (specifically STAT6) only in MV4-11 cells with the FLT3-ITD mutation. Further findings revealed that HO1 overexpression confers gilteritinib resistance in FLT3-ITD AML cell lines and primary individual specimens. While suppression of HO1 sensitized FLT3-ITD AML cell lines and primary individual specimens to gilteritinib. Mechanistically, western blotting and flow cytometry confirmed that HO1-mediated gilteritinib resistance is related to STAT6 phosphorylation in FLT3-ITD AML cell lines and primary individual specimens. Moreover, tumor-bearing mice were employed to determine that HO1 overexpression conferred gilteritinib resistance in vivo. Collectively, these studies illustrate that HO1 may act as a successful treatment target for gilteritinib-resistant FLT3-ITD AML patients. The online version contains supplementary material available at 10.1186/s12935-025-03757-3.

Trogocytosis is the process by which a recipient cell siphons small membrane fragments and proteins from a donor cell and can be utilized by cancer cells to avoid immune detection. We observed lymphocyte specific protein expressed by triple negative breast cancer (TNBC) cells via immunofluorescence imaging of patient samples. Image analysis of Cluster of Differentiation 45RA (CD45RA) expression, a naïve T cell specific protein, revealed that all stages of TNBCs express CD45RA. Flow cytometry revealed TNBC cells trogocytose CD45 protein from T cells. We also showed that the acquisition of these lymphoid markers is contact dependent. Confocal and super-resolution imaging further revealed CD45+ spherical structures containing T cell genomic DNA inside TNBC cells after co-culture. Trogocytosis between T cells and TNBC cells altered tumor cell expression of PTPRC , the gene that encodes for CD45. Our results revealed that CD45 is obtained by TNBC cells from T cells via trogocytosis and that TNBC cells express CD45 intracellularly and on the membrane.