Single‐cell profiling of ineffective erythropoiesis in a mouse model of β‐thalassaemia intermedia

Summary Beta‐thalassaemia is an inherited haemoglobin disorder characterised by ineffective erythropoiesis (IE). The detailed pathogenesis of IE remains unclear. In this study, we used single‐cell RNA sequencing (scRNA‐seq) to examine IE in Th3/+ β‐thalassaemic mice. The results showed that the erythroid group was remarkably expanded, and genes involved in biological processes such as iron metabolism, haeme synthesis, protein folding, and response to heat were significantly upregulated from erythroid progenitors to reticulocytes in β‐thalassaemic mice. In particular, we identified a unique cell population close to reticulocytes, named ThReticulocytes, characterised by a high level of heat shock protein 70 (Hsp70) expression and dysregulation of iron metabolism and haeme synthesis signalling. Treatment of β‐thalassaemic mice with the haeme oxygenase inhibitor tin‐mesoporphyrin effectively improved the iron disorder and IE, and the ThReticulocyte population and Hsp70 expression were significantly suppressed. This study revealed in detail the progression of IE at the single‐cell level and possibly provided clues to find therapeutic targets in thalassaemia.