Single-Cell Transcriptomics of Haematopoietic Progenitors in Sickle Cell Disease: Characterising Ineffective Erythropoiesis at the Molecular Level in South East Nigeria

Ineffective erythropoiesis in sickle cell disease is driven by premature destruction of erythroid progenitors, yet the molecular heterogeneity of haematopoietic progenitor cell populations responsible for this process has not been characterised in Nigerian HbSS patients using single-cell resolution approaches. This study applies single-cell RNA sequencing to bone marrow aspirate-derived haematopoietic progenitors from HbSS patients in Anambra and Imo States, South East Nigeria, to characterise molecular trajectories of ineffective erythropoiesis. A case-control design was employed, with 20 HbSS patients, 10 HbAS carriers, and 10 HbAA controls from whom bone marrow aspirates were collected under local anaesthesia. Single-cell libraries were constructed using the 10X Genomics Chromium platform and sequenced on an Illumina NovaSeq 6000. Cell type annotation, trajectory inference by Monocle 3, and regulon analysis by SCENIC identified transcription factor networks driving aberrant erythroid differentiation. Protein-level validation of key regulatory nodes was performed by CyTOF mass cytometry. Pseudotime analysis mapped molecular events from progenitor commitment to enucleation block. This study generates an original single-cell molecular atlas of sickle cell erythropoiesis in an African population and identifies transcriptional targets for erythropoiesis-stimulating therapeutic approaches. Keywords: single-cell transcriptomics, sickle cell disease, ineffective erythropoiesis, haematopoietic progenitors, South East Nigeria.