{ "items": [ "\n\n
<p>Supplementary Table 2 Gene sets for GSEA</p>
\n \n\n \n \n<p>Supplementary Table 1 VEGFAC Top Differentially Expressed Genes by Cluster</p>
\n \n\n \n \n<p>MM ALL Donor Details</p>
\n \n\n \n \n<p>Supplementary Table 6 qRT PCR Probes</p>
\n \n\n \n \n<p>Supplementary Table 5 Antibodies</p>
\n \n\n \n \n<p>Supplementary Table 7 NGS Panel</p>
\n \n\n \n \n<p>Supplementary Table 3 HD and MPN samples.</p>
\n \n\n \n \n<p>MM ALL Donor Details</p>
\n \n\n \n \n<p>Supplementary Table 3 HD and MPN samples.</p>
\n \n\n \n \n<p>Supplementary Materials and Methods, Supplementary Figures S1-S12</p>
\n \n\n \n \n<p>Supplementary Table 7 NGS Panel</p>
\n \n\n \n \n<div>Abstract<p>A lack of models that recapitulate the complexity of human bone marrow has hampered mechanistic studies of normal and malignant hematopoiesis and the validation of novel therapies. Here, we describe a step-wise, directed-differentiation protocol in which organoids are generated from induced pluripotent stem cells committed to mesenchymal, endothelial, and hematopoietic lineages. These 3D structures capture key features of human bone marrow\u2014stroma, lumen-forming sinusoids, and myeloid cells including proplatelet-forming megakaryocytes. The organoids supported the engraftment and survival of cells from patients with blood malignancies, including cancer types notoriously difficult to maintain <i>ex vivo</i>. Fibrosis of the organoid occurred following TGF\u03b2 stimulation and engraftment with myelofibrosis but not healthy donor\u2013derived cells, validating this platform as a powerful tool for studies of malignant cells and their interactions within a human bone marrow\u2013like milieu. This enabling technology is likely to accelerate the discovery and prioritization of novel targets for bone marrow disorders and blood cancers.</p>Significance:<p>We present a human bone marrow organoid that supports the growth of primary cells from patients with myeloid and lymphoid blood cancers. This model allows for mechanistic studies of blood cancers in the context of their microenvironment and provides a much-needed <i>ex vivo</i> tool for the prioritization of new therapeutics.</p><p><i><a href=\"https://aacrjournals.org/cancerdiscovery/article/doi/10.1158/2159-8290.CD-22-1303\" target=\"_blank\">See related commentary by Derecka and Crispino, p. 263</a>.</i></p><p><i><a href=\"https://aacrjournals.org/cancerdiscovery/article/doi/10.1158/2159-8290.CD-13-2-ITI\" target=\"_blank\">This article is highlighted in the In This Issue feature, p. 247</a></i></p></div>
\n \n\n \n \nINTRODUCTION: Azacitidine (AZA) is an approved frontline therapy for higher-risk myelodysplastic syndromes (HR-MDS); however, poor survival denotes unmet needs to increase depth/duration of response (DOR). METHODS: This retrospective study with patient chart review evaluated AZA effectiveness in 382 treatment-naive patients with HR-MDS from a US electronic health record (EHR)-derived database. Responses were assessed using International Working Group (IWG) 2006 criteria; real-world equivalents were derived from EHRs. Primary endpoint was IWG 2006-based complete remission rate (CRR). Secondary endpoints were EHR-based CRR, IWG 2006- and EHR-based objective response rates (ORRs), duration of CR, DOR, progression-free survival, time-to-next-treatment, and overall survival (OS). RESULTS: Using IWG 2006 criteria, the CRR was 7.9% (n\u00a0=\u00a030); median duration of CR was 12.0 months (95% CI, 7.7-15.6). In poor cytogenetic risk (n\u00a0=\u00a0101) and TP53 mutation (n\u00a0=\u00a046) subgroups, CRRs were 7.9% (n\u00a0=\u00a08) and 8.7% (n\u00a0=\u00a04), respectively. ORR was 62.8% (n\u00a0=\u00a0240), including a hematologic improvement rate (HIR) of 46.9% (n\u00a0=\u00a0179). Using EHR-based data, CRR was 3.7% (n\u00a0=\u00a014); median duration of CR was 13.5 months (95% CI, 4.5-21.5). ORR was 67.8% (n\u00a0=\u00a0259), including an HIR of 29.3% (n\u00a0=\u00a0112). Median follow-up was 12.9 months; median OS was 17.9 months (95% CI, 15.5-21.7). CONCLUSIONS: Consistent with other studies, CRRs and median OS with AZA in treatment-naive patients with HR-MDS were low in this large, real-world cohort. Novel agents/combinations are urgently needed to improve these outcomes in HR-MDS.
\n \n\n \n \nThe Bloom syndrome helicase BLM interacts with topoisomerase III\u03b1 (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex. We show that this is due to a previously overlooked role for BARD1 in recruiting SLX4 to resolve DNA intermediates left unprocessed by BLM in the preceding interphase. Consequently, cells with defective BLM and BRCA1-BARD1 accumulate catastrophic levels of chromosome breakage and micronucleation, leading to cell death. Thus, we reveal mechanistic insights into SLX4 recruitment to DNA lesions, with potential clinical implications for treating BRCA1-deficient tumors.
\n \n\n \n \nHuman bone marrow failure (BMF) syndromes result from the loss of hematopoietic stem and progenitor cells (HSPC), and this loss has been attributed to cell death; however, the cell death triggers, and mechanisms remain unknown. During BMF, tumor necrosis factor-\u03b1 (TNF\u03b1) and interferon-\u03b3 (IFN\u03b3) increase. These ligands are known to induce necroptosis, an inflammatory form of cell death mediated by RIPK1, RIPK3, and MLKL. We previously discovered that mice with a hematopoietic RIPK1 deficiency (Ripk1HEM KO) exhibit inflammation, HSPC loss, and BMF, which is partially ameliorated by a RIPK3 deficiency; however, whether RIPK3 exerts its effects through its function in mediating necroptosis or other forms of cell death remains unclear. Here, we demonstrate that similar to a RIPK3 deficiency, an MLKL deficiency significantly extends survival and like Ripk3 deficiency partially restores hematopoiesis in Ripk1HEM KO mice revealing that both necroptosis and apoptosis contribute to BMF in these mice. Using mouse models, we show that the nucleic acid sensor Z-DNA binding protein 1 (ZBP1) is up-regulated in mouse RIPK1-deficient bone marrow cells and that ZBP1's function in endogenous nucleic acid sensing is necessary for HSPC death and contributes to BMF. We also provide evidence that IFN\u03b3 mediates HSPC death in Ripk1HEM KO mice, as ablation of IFN\u03b3 but not TNF\u03b1 receptor signaling significantly extends survival of these mice. Together, these data suggest that RIPK1 maintains hematopoietic homeostasis by preventing ZBP1 activation and induction of HSPC death.
\n \n\n \n \nIron overloading disorders linked to mutations in ferroportin have diverse phenotypes in vivo, and the effects of mutations on ferroportin in vitro range from loss of function (LOF) to gain of function (GOF) with hepcidin resistance. We reviewed 359 patients with 60 ferroportin variants. Overall, macrophage iron overload and low/normal transferrin saturation (TSAT) segregated with mutations that caused LOF, while GOF mutations were linked to high TSAT and parenchymal iron accumulation. However, the pathogenicity of individual variants is difficult to establish due to the lack of sufficiently reported data, large inter-assay variability of functional studies, and the uncertainty associated with the performance of available in silico prediction models. Since the phenotypes of hepcidin-resistant GOF variants are indistinguishable from the other types of hereditary hemochromatosis (HH), these variants may be categorized as ferroportin-associated HH, while the entity ferroportin disease may be confined to patients with LOF variants. To further improve the management of ferroportin disease, we advocate for a global registry, with standardized clinical analysis and validation of the functional tests preferably performed in human-derived enterocytic and macrophagic cell lines. Moreover, studies are warranted to unravel the definite structure of ferroportin and the indispensable residues that are essential for functionality.
\n \n\n \n \nBACKGROUND: How specific nutrients influence adaptive immunity is of broad interest. Iron deficiency is the most common micronutrient deficiency worldwide and imparts a significant burden of global disease; however, its effects on immunity remain unclear. METHODS: We used a hepcidin mimetic and several genetic models to examine the effect of low iron availability on T\u00a0cells in\u00a0vitro and on immune responses to vaccines and viral infection in mice. We examined humoral immunity in human patients with raised hepcidin and low serum iron caused by mutant TMPRSS6. We tested the effect of iron supplementation on vaccination-induced humoral immunity in piglets, a natural model of iron deficiency. FINDINGS: We show that low serum iron (hypoferremia), caused by increased hepcidin, severely impairs effector and memory responses to immunizations. The intensified metabolism of activated lymphocytes requires the support of enhanced iron acquisition, which is facilitated by IRP1/2 and TFRC. Accordingly, providing extra iron improved the response to vaccination in hypoferremic mice and piglets, while conversely, hypoferremic humans with chronically increased hepcidin have reduced concentrations of antibodies specific for certain pathogens. Imposing hypoferremia blunted the T\u00a0cell, B cell, and neutralizing antibody responses to influenza virus infection in mice, allowing the virus to persist and exacerbating lung inflammation and morbidity. CONCLUSIONS: Hypoferremia, a well-conserved physiological innate response to infection, can counteract the development of adaptive immunity. This nutrient trade-off is relevant for understanding and improving immune responses to infections and vaccines in the globally common contexts of iron deficiency and inflammatory disorders. FUNDING: Medical Research Council, UK.
\n \n\n \n \nVaccines are the most effective measure to prevent deaths and illness from infectious diseases. Nevertheless, the efficacy of several paediatric vaccines is lower in low-income and middle-income countries (LMICs), where mortality from vaccine-preventable infections remains high. Vaccine efficacy can also be decreased in adults in the context of some common comorbidities. Identifying and correcting the specific causes of impaired vaccine efficacy is of substantial value to global health. Iron deficiency is the most common micronutrient deficiency worldwide, affecting more than 2 billion people, and its prevalence in LMICs could increase as food security is threatened by the COVID-19 pandemic. In this Viewpoint, we highlight evidence showing that iron deficiency limits adaptive immunity and responses to vaccines, representing an under-appreciated additional disadvantage to iron deficient populations. We propose a framework for urgent detailed studies of iron-vaccine interactions to investigate and clarify the issue. This framework includes retrospective analysis of newly available datasets derived from trials of COVID-19 and other vaccines, and prospective testing of whether nutritional iron interventions, commonly used worldwide to combat anaemia, improve vaccine performance.
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