Blood advances最新文献

Abstract: Among the most common genetic alterations in myelodysplastic syndromes (MDS) are mutations in the spliceosome gene SF3B1. Such mutations induce specific RNA missplicing events, directly promote ring sideroblast (RS) formation, and generally associate with a more favorable prognosis. However, not all SF3B1 mutations are the same, and little is known about how distinct hotspots influence disease. Here, we report that the E592K variant of SF3B1 associates with high-risk disease features in MDS, including a lack of RS, increased myeloblasts, a distinct comutation pattern, and a lack of favorable survival seen with other SF3B1 mutations. Moreover, compared with other hot spot SF3B1 mutations, E592K induces a unique RNA missplicing pattern, retains an interaction with the splicing factor SUGP1, and preserves normal RNA splicing of the sideroblastic anemia genes TMEM14C and ABCB7. These data have implications for our understanding of the functional diversity of spliceosome mutations, as well as the pathobiology, classification, prognosis, and management of SF3B1-mutant MDS.

Abstract: A variety of autosomal recessive mutations in the JAGN1 gene cause severe congenital neutropenia (CN). However, the underlying pathomechanism remains poorly understood, mainly because of the limited availability of primary hematopoietic stem cells from JAGN1-CN patients and the absence of animal models. In this study, we aimed to address these limitations by establishing a zebrafish model of JAGN1-CN. We found 2 paralogs of the human JAGN1 gene, namely jagn1a and jagn1b, which play distinct roles during zebrafish hematopoiesis. Using various approaches such as morpholino-based knockdown, CRISPR/Cas9-based gene editing, and misexpression of a jagn1b harboring a specific human mutation, we successfully developed neutropenia while leaving other hematopoietic lineages unaffected. Further analysis of our model revealed significant upregulation of apoptosis and genes involved in the unfolded protein response (UPR). However, neither UPR nor apoptosis is the primary mechanism that leads to neutropenia in zebrafish. Instead, Jagn1b has a critical role in granulocyte colony-stimulating factor receptor signaling and steady-state granulopoiesis, shedding light on the pathogenesis of neutropenia associated with JAGN1 mutations. The establishment of a zebrafish model for JAGN1-CN represents a significant advancement in understanding the specific pathologic pathways underlying the disease. This model provides a valuable in vivo tool for further investigation and exploration of potential therapeutic strategies.

Abstract: Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell (PC) neoplasm that may evolve with variable frequency into multiple myeloma (MM). SMM is initiated by chromosomal translocations involving the immunoglobulin heavy-chain locus or by hyperdiploidy and evolves through acquisition of additional genetic lesions. In this scenario, we aimed at establishing a reliable analysis pipeline to infer genomic lesions from transcriptomic analysis, by combining single-cell RNA sequencing (scRNA-seq) with B-cell receptor sequencing and copy number abnormality (CNA) analysis to identify clonal PCs at the genetic level along their specific transcriptional landscape. We profiled 20 465 bone marrow PCs derived from 5 patients with SMM/MM and unbiasedly identified clonal and polyclonal PCs. Hyperdiploidy, t(11;14), and t(6;14) were identified at the scRNA level by analysis of chimeric reads. Subclone functional analysis was improved by combining transcriptome with CNA analysis. As examples, we illustrate the different functional properties of a light-chain escape subclone in SMM and of different B-cell and PC subclones in a patient affected by Wäldenstrom macroglobulinemia and SMM. Overall, our data provide a proof of principle for inference of clinically relevant genotypic data from scRNA-seq, which in turn will refine functional annotation of the clonal architecture of PC dyscrasias.

Abstract: Chimeric antigen receptor (CAR) T-cell therapy has emerged as a promising immunotherapeutic strategy for eradicating human cancers. Their therapeutic success and durability of clinical responses hinges, in large part, on their functional capacity, including the ability of these engineered cells to simultaneously expand and persist after infusion into patients. CD19 CAR T-cell polyfunctionality, assessing the simultaneous functions of cytokine production, proliferation, and cytotoxicity has been reported to correlate with clinical outcomes. Assay optimization is potentially limited by the heterogeneous nature of CAR T-cell infusion products and target specificity. We optimized a single-cell platform for polyfunctionality using CAR T-cell products manufactured from healthy donors, engineered against a novel target, B-cell-activating factor receptor (BAFF-R) and validated the protocol using CD19 CAR T cells. We observed distinct qualitative differences between BAFF-R and CD19 CAR T cells relative to the proportions of stimulatory vs effector cytokines, based on target antigen density, and, generally, CD19 CAR T cells exhibited lower indices of polyfunctionality. Finally, we applied our assay to the autologous BAFF-R CAR T-cell product generated from the first patient with non-Hodgkin lymphoma treated in an ongoing clinical trial who had progressed after prior CD19 CAR T-cell therapy. We observed robust indicators of polyfunctionality, which correlated with successful CAR T-cell expansion after infusion and achievement of durable complete remission ongoing after 18 months. The precise identification of factors determining the role of BAFF-R CAR T-cell fitness in toxicity and clinical outcome will require the application of this robust assay in the analysis of additional treated patients. This trial was registered at www.ClinicalTrials.gov as #NCT05370430.

Abstract: Allogeneic T cells reprogram their metabolism during acute graft-versus-host disease (GVHD) in a process involving the cellular energy sensor adenosine monophosphate (AMP)-activated protein kinase (AMPK). Deletion of AMPK in donor T cells limits GVHD but still preserves homeostatic reconstitution and graft-versus-leukemia effects. In the current studies, murine AMPK knock-out (KO) T cells decreased oxidative metabolism at early time points posttransplant and lacked a compensatory increase in glycolysis after inhibition of the electron transport chain. Immunoprecipitation using an antibody specific to phosphorylated targets of AMPK determined that AMPK modified interactions of several glycolytic enzymes including aldolase, enolase, pyruvate kinase M, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH), with enzyme assays confirming impaired aldolase and GAPDH activity in AMPK KO T cells. Importantly, these changes in glycolysis correlated with both an impaired ability of AMPK KO T cells to produce significant amounts of interferon gamma upon antigenic restimulation and a decrease in the total number of donor CD4 T cells recovered at later times posttransplant. Human T cells lacking AMPK gave similar results, with glycolytic compensation impaired both in vitro and after expansion in vivo. Xenogeneic GVHD results also mirrored those of the murine model, with reduced CD4/CD8 ratios and a significant improvement in disease severity. Together these data highlight a significant role for AMPK in controlling oxidative and glycolytic metabolism in both murine and human T cells and endorse further study of AMPK inhibition as a potential clinical target for future GVHD therapies.

Abstract: The lack of consensus on acceptable primary end points and definitions of response and survival in phase 2/3 efficacy studies for adult acute lymphoblastic leukemia has led to widely different clinical trial designs. Inconsistency in primary end point selection and lack of consensus on response, survival end points, and adequate follow-up time lead to difficulty in interpreting completed studies and developing future trials. The lack of consensus also runs the risk of integrating ineffective or unacceptably toxic regimens into clinical practice and future trials. Increasingly, studies integrating highly active, targeted agents into chemotherapy use short-term end points of response, measurable residual disease-negative response, and early event-free survival without confidence that these end points will translate into improved late patient outcomes. This article highlights the current consequences and dilemmas caused by this lack of consensus. The hope is to stimulate discussion and ultimately consensus to improve the interpretation and application of clinical trial results.

Abstract: Severe aplastic anemia (SAA) is a rare hematologic condition for which there is no clear management algorithm. A panel of 11 experts on adult and pediatric aplastic anemia was assembled and, using the RAND/University of California, Los Angeles modified Delphi panel method, evaluated >600 varying patient care scenarios to develop clinical recommendations for the initial and subsequent management of patients of all ages with SAA. Here, we present the panel's recommendations to rule out inherited bone marrow failure syndromes, on supportive care before and during first-line therapy, and on first-line (initial management) and second-line (subsequent management) therapy of acquired SAA, focusing on when transplant vs medical therapy is most appropriate. These recommendations represent the consensus of 11 experts informed by published literature and experience. They are intended only as general guidance for experienced clinicians who treat patients with SAA and are in no way intended to supersede individual physician and patient decision making. Current and future research should validate this consensus using clinical data. Once validated, we hope these expert panel recommendations will improve outcomes for patients with SAA.