A natural DNMT1 mutation elevates the fetal hemoglobin level via epigenetic derepression of the γ-globin gene in ß-thalassemia.

DNA methyltransferase 1 (DNMT1) is a major epigenetic regulator of the formation of large macromolecular complexes that repress human γ-globin expression by maintaining DNA methylation. However, very little is known about the association of DNMT1 variants with ß-thalassemia phenotypes. We systematically investigated associations between variants in DNMT1 and phenotypes in 1142 ß-thalassemia subjects and identified a novel missense mutation (c.2633G>A, S878F) in the DNMT1 bromo-adjacent homology-1 (BAH1) domain. We functionally characterized this mutation in CD34+ cells from patients and engineered HuDEP-2 mutant cells. Our results demonstrate that DNMT1 phosphorylation is abrogated by substituting serine with phenylalanine at position 878, resulting in lower stability and catalytic activity loss. S878F mutation also attenuated DNMT1 interactions with BCL11A, GATA1, and HDAC1/2, and reduced recruitment of DNMT1 to the γ-globin (HBG) promoters, leading to epigenetic derepression of γ-globin expression. By analyzing the F-cell pattern, we demonstrated that the effect of DNMT1 mutation on increased fetal hemoglobin (HbF) is heterocellular. Furthermore, introduction of S878F mutation into erythroid cells by clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) recapitulated γ-globin reactivation. Thus, the natural S878F DNMT1 mutation is a novel modulator of HbF synthesis and represents a potential new therapeutic target for ß-hemoglobinopathies.

Analysis of Hematological Indices and Splenectomy Rates in 2,130 Patients with Hemoglobin H Diseases or ß-Thalassemia.

INTRODUCTION: Splenomegaly and hypersplenism are common complications of thalassemia patients due to the excessive clearance of defective red blood cells from the spleen. To date, splenectomy has been considered one of the most effective treatments for splenomegaly, reducing clinical severity among thalassemia patients. Thus, we aim to investigate the differences in splenectomy rates and hematological indices among thalassemia patients with different genotypes. METHOD: In this study, we analyzed the clinical data of thalassemia in 2,130 patients admitted to the 923rd Hospital of the People's Liberation Army from January 2006 to December 2020, and the statistical software SPSS 26.0 was applied to analyze the data. RESULT: Of the 2,130 patients with thalassemia, 265 patients underwent splenectomy. It was determined that significantly more patients with hemoglobin H (HbH) disease, a form of α-thalassemia, have undergone splenectomy than ß-thalassemia patients (20% vs. 7%). Further, HbH disease patients were diagnosed at a significantly older age than ß-thalassemia patients. CONCLUSION: The greater probability of HbH disease patients undergoing splenectomy is likely influenced by multiple factors, including their lower dependency on transfusion, leading to high spleen compensatory stress on the spleen, and the destruction of defective erythrocytes. In contrast, ß-thalassemia is clinically more severe and less tolerant of hemoglobin fluctuations. Based on these findings, clinicians are suggested to pay more attention to HbH disease patients as many of them are still under-transfused, which could lead to chronic hemolysis and more severe hepatosplenomegaly. These results might offer insight for improving the clinical management of patients with different types of thalassemia.

Humanoid Robot Cooperative Motion Control Based on Optimal Parameterization.

The implementation of low-energy cooperative movements is one of the key technologies for the complex control of the movements of humanoid robots. A control method based on optimal parameters is adopted to optimize the energy consumption of the cooperative movements of two humanoid robots. A dynamic model that satisfies the cooperative movements is established, and the motion trajectory of two humanoid robots in the process of cooperative manipulation of objects is planned. By adopting the control method with optimal parameters, the parameters optimization of the energy consumption index function is performed and the stability judgment index of the robot in the movement process is satisfied. Finally, the effectiveness of the method is verified by simulations and experimentations.

[Oxidative Stress Status and Its Effect on Regulation of Hepcidin in Patients with HbHCS].

OBJECTIVE: To investigate the oxidative stress status and its effects on hepcidin in patients with hemoglobin H Constant Spring disease (HbH-CS). METHODS: A total of 35 patients were enrolled in the study, including 15 splenectomized cases and 20 non-splenectomized cases. 20 healthy volunteers were selected as controls. Serum superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG) levels, erythropoietin (EPO), serum free transferrin receptor (sFTR), growth differentiation factor 15 (GDF15) as well as the level of hepcidin were detected. Correlation analysis and multiple factor regression analysis were performed to investigate the factors affecting the iron metabolism and erythropoiesis. RESULTS: Compared with healthy control, the SOD and GSH levels in patients with HbHCS decreased, while MDA and GSSG levels increased. The levels of SOD, MDA, GSG and GSSG were not significantly different between the patients with splenectomy and those without splenectomy. Correlation analysis showed that inpatients with HbHCS, EPO, sFTR and GDF15 correlated negatively with SOD level and positively with MDA level. EPO and sFTR levels negatively correlated with Hepcidin. CONCLUSION: Excessive oxidative stress is present in patients with HbHCS, and hepcidin is inhibited by the upregulation of EPO and sFTR, and hence involved in iron overload in patients.