bims-conane 2025-03-16 papers

Blood Adv. 2025 Mar 14. pii: bloodadvances.2024013591. [Epub ahead of print]

MITAPIVAT METABOLICALLY REPROGRAMS HUMAN BETA-THALASSEMIC ERYTHROBLASTS, INCREASING THEIR RESPONSIVENESS TO OXIDATION.

Angela Siciliano, Angelo D'Alessandro, Alessandro Matte, Giovanni Bisello, Mariarita Bertoldi, Monika Dzieciatkowska, Amy Argabright, Richard Huot Pozzetto, Veronica Riccardi, Andrea Mattarei, Alberto Ongaro, Jacopo Ceolan, Roberta Russo, Leonardo Rivadeneyra, Megan Wind-Rotolo, Achille Iolascon, Carlo Brugnara, Lucia De Franceschi.

beta-thalassemia (beta-thal) is a worldwide hereditary red cell disorder characterized by severe chronic anemia. Recently, the pyruvate kinase (PK) activator mitapivat has been shown to improve anemia and ineffective erythropoiesis in a mouse model of beta-thal and in non-transfusion dependent thalassemic patients. Here, we showed that in vitro CD34+ derived erythroblasts from beta-thal (codb039) patients are characterized by persistent expression of two PK isoforms, PKR and PKM2, when compared to healthy cells. Activation of PKR and PKM2 via mitapivat promoted a significant metabolic reprogramming of beta-thal erythroblasts, resulting in higher levels of high-energy phosphate compounds, including adenosine triphosphate (ATP) and triphosphate nucleoside pools. Proteomics analyses revealed an accumulation of PKR, suggesting a possible beneficial effect of mitapivat on the stability of PKs. Increased ATP availability was accompanied by a higher degree of protein phosphorylation, especially of proteins involved in cell cycle regulation at the transcriptional, translational, and post-translational levels, supporting the effect of mitapivat on erythroid maturation. Upon treatment with mitapivat, beta-thal erythroblasts showed decreased markers of oxidation, including cysteine oxidative post-translational modifications, down-regulation of HSP-70 and Prdx2 expression, and normalization of the redox-dependent sub-cellular distribution of the latter enzyme. Collectively, our data support a protective effect of mitapivat in beta-thal erythropoiesis, an effect favored by its activation of persistently expressed PKR and PKM2. In addition to the anticipated benefits on energy metabolism, we report that mitapivat treatment mitigated the oxidative damage in beta-thal erythropoiesis, ensuring improved beta-thal erythroblast maturation and survival.

DOI: https://doi.org/10.1182/bloodadvances.2024013591

Br J Haematol. 2025 Mar 09.

Real-world insights from a cohort of approximately 2000 individuals who were analysed using a freely available next-generation sequencing anaemia screening programme.

Jorune Balciuniene, Saliha Yilmaz, Satheesh Chonat, Rachael F Grace, Gerald A Soff, Yaddanapudi Ravindranath, Bertil Glader, Paola Bianchi, Bryan McGee, Archana M Agarwal, Geetha Puthenveetil.

Data from a large cohort of individuals referred for NGS testing evaluate the utility of next-generation sequencing in clinical practice for diagnosing hereditary haemolytic anaemias.

DOI: https://doi.org/10.1111/bjh.20049

Biochem Biophys Res Commun. 2025 Mar 01. pii: S0006-291X(25)00277-3. [Epub ahead of print]756 151563

RPS24 haploinsufficiency impairs erythropoiesis in the Diamond-Blackfan anemia zebrafish model via the STAT6-SATB1 pathway.

Soyul Ahn, Chang-Kyu Oh.

Diamond-Blackfan anemia (DBA) is a rare bone marrow failure disorder primarily caused by mutations in ribosomal proteins (RPs), including RPS24, leading to impaired erythropoiesis. Despite advances in our understanding of the roles of other RPs, the mechanisms underlying RPS24-related DBA remain unclear. Therefore, in this study, we aimed to investigate the effect of RPS24 haploinsufficiency on erythropoiesis using a zebrafish model. RPS24 knockdown via morpholino injection significantly reduced the hemoglobin levels, as confirmed by O-dianisidine staining and whole-mount in situ hybridization. Further analysis revealed that RPS24 deficiency downregulated the expression of SATB homeobox 1a (satb1a), a key regulator of erythroid differentiation, by inhibiting the signal transducer and activator of transcription 6 (STAT6) signaling pathway. Western blotting analysis revealed decreased levels of pSTAT6 correlated with the decrease in downstream erythroid marker levels. satb1a knockdown further impaired erythropoiesis in zebrafish, reinforcing its critical role in DBA pathogenesis. Overall, our findings suggest that RPS24 haploinsufficiency leads to DBA by disrupting the STAT6-SATB1 axis, providing novel insights into the molecular mechanisms underlying erythropoietic failure in DBA. Furthermore, this study highlights the importance of zebrafish models for further exploration of therapeutic targets for DBA.

Keywords: Diamond–Blackfan anemia; Erythropoiesis; RPS24; SATB1; STAT6; Zebrafish

DOI: https://doi.org/10.1016/j.bbrc.2025.151563

Blood Adv. 2025 Mar 03. pii: bloodadvances.2024015347. [Epub ahead of print]

Identification of two novel non-coding variants in Diamond-Blackfan Anemia Syndrome patients by whole genome sequencing.

Ting Wen, Steven E Boyden, Caleb M Hocutt, Robert G Lewis, Erin E Baldwin, Jennie Vagher, Ashley Andrews, Thomas J Nicholas, Alexander Chapin, Elaine M Fan, Lorenzo D Botto, Pinar Bayrak-Toydemir, Rong Mao, Jessica Meznarich.

Diamond-Blackfan Anemia Syndrome (DBAS) is a rare congenital disorder with variable penetrance and expressivity, characterized by pure red cell aplasia that typically manifests as early-onset chronic macrocytic or normocytic anemia and is often associated with other congenital anomalies. DBAS is etiologically heterogeneous, with over 20 known DBAS-associated genes encoding small and large ribosomal protein subunits, and an inheritance pattern largely as autosomal dominant or sporadic. We report two DBAS cases with prior negative genetic testing, which included targeted gene panels, karyotype analysis, chromosome breakage analysis, and whole exome sequencing (WES). Although clinical whole genome sequencing (WGS) was initially negative, in-depth reanalysis identified two novel non-coding variants in the RPS gene family: a maternally inherited splicing variant at the end of the first non-coding exon in RPS7 (NM_001011.4, c.-19G>C) in Family 1, and a deep intronic de novo variant in RPS19 (NM_001022.4, c.172+350C>T) in Family 2. In Family 1, several maternal relatives were identified as sharing the same variant through cascade testing; clinically, they exhibited variable degrees of anemia and elevated erythrocyte adenosine deaminase (eADA) activity, a marker for DBAS. RNA sequencing analysis demonstrated deleterious functional consequences for both non-coding variants. In Case 1, hematopoietic stem cell transplant (HSCT) with an unaffected matched sibling donor, who did not carry the variant, successfully cured the congenital anemia. This study identified novel non-coding variants and underscores the clinical utility of WGS in accelerating diagnosis and improving care for rare genetic disorders, particularly when timely treatment decisions are critically important.

DOI: https://doi.org/10.1182/bloodadvances.2024015347