β-thalassemia is a hematologic disease that may be associated with significant morbidity and mortality. Increased expression of HBG1/2 can ameliorate the severity of β-thalassemia. Compared to the unaffected population, some β-thalassemia patients display elevated HBG1/2 expression levels in their red blood cells. However, the magnitude of up-regulation does not reach the threshold of self-healing, and thus, the molecular mechanism underlying HBG1/2 expression in the context of HBB-deficiency requires further elucidation. Here, we performed a multi-omics study examining chromatin accessibility, transcriptome, proteome, and phosphorylation patterns in the HBB homozygous knockout of the HUDEP2 cell line (HBB-KO). We found that up-regulation of HBG1/2 in HBB-KO cells was not induced by the H3K4me3-mediated genetic compensation response. Deletion of HBB in human erythroid progenitor cells resulted in increased ROS levels and production of oxidative stress, which led to an increased rate of apoptosis. Furthermore, in response to oxidative stress, slower cell cycle progression and proliferation were observed. In addition, stress erythropoiesis was initiated leading to increased intracellular HBG1/2 expression. This molecular model was also validated in the single-cell transcriptome of hematopoietic stem cells from β-hemoglobinopathy patients. These findings further the understanding of HBG1/2 gene regulatory networks and provide novel clinical insights into β-thalassemia phenotypic diversity.

The msh homeobox 1 (Msx1) and msh homeobox 2 (Msx2) coordinate in myoblast differentiation and also contribute to muscle defects if altered during development. Deciphering the downstream signaling networks of Msx1 and Msx2 in myoblast differentiation will help us to understand the molecular events that contribute to muscle defects. Here, the proteomics characteristics in Msx1- and Msx2-mediated myoblast differentiation was evaluated using isobaric tags for the relative and absolute quantification labeling technique (iTRAQ). The downstream regulatory proteins of Msx1- and Msx2-mediated differentiation were identified. Bioinformatics analysis revealed that these proteins were primarily associated with xenobiotic metabolism by cytochrome P450, fatty acid degradation, glycolysis/gluconeogenesis, arginine and proline metabolism, and apoptosis. In addition, our data show Acta1 was probably a core of the downstream regulatory networks of Msx1 and Msx2 in myoblast differentiation.