Cholesterol‐conjugated miR‐29b induces fetal haemoglobin expression via γ‐globin promoter demethylation in the Townes mouse model for sickle cell anaemia

• DOI: 10.1111/bjh.20107
• Publication Date: 2025-05-05T04:08:09Z
• Authors: Chithra D. Palani; Alana Smith; Xueyuan Cao; Biaoru Li; Betty S. Pace; Athena Starlard‐D...

SummaryCholesterol‐conjugated miRNA has emerged as a viable system for preventing small molecule degradation in plasma with low toxicity and high delivery efficiency. We previously established that miR‐29b induces fetal haemoglobin (HbF) in Townes sickle cell anaemia (SCA) mice using a continuous infusion mini‐osmotic pump. Herein, we expanded the scope of our work to determine the ability of intermittent subcutaneous cholesterol‐conjugated miR‐29b (Chol‐miR‐29b) to induce HbF expression in SCA mice. Blood was collected for automated complete blood counts with differential, reticulocyte count and γ‐globin and βS‐globin mRNA levels quantified by reverse transcription‐quantitative PCR; flow cytometry measured the percentage of HbF‐positive cells (F‐cells). Methylation assays determined 5‐methylcytosine levels, and RNA sequencing changes in gene expression for different treatment conditions. SCA mice receiving Chol‐miR‐29b exhibited normal behaviour and weight gain without peripheral blood count toxicity. The γ‐globin mRNA levels significantly increased, and F‐cell percentages were enhanced after Chol‐miR‐29b treatment. Subsequently, spleen tissue confirmed decreased DNMT3A protein and 5‐methylcytosine levels in the γ‐globin gene promoter. RNA‐seq analysis supports oncogene silencing and tumour suppressor gene activation by Chol‐miR‐29b. These data demonstrate that a daily subcutaneous dose of Chol‐miR‐29b induces HbF expression, highlighting its potential for clinical development in SCA.