TRANSLATIONAL Research

Translational: method for erythrocyte microRNA profiling in anemia disorders identifies specific defect in sickle cell disease erythrocytes and erythroid progenitors 

Isolation and characterization of microRNAs of human mature erythrocytes. (Methods Mol Biol. 2010)

MicroRNA miR-144 modulates oxidative stress tolerance and associates with anemia severity in sickle cell disease. (Blood 2010)

cited in selected review(s): Erythrocyte microRNAs: a tiny magic bullet with great potential for sickle cell disease therapy (Ann Hemat 2021)

Approaches to study of the molecular basis of phenotypic heterogeneity in Sickle Cell Disease in the past have used candidate genes, quantitative trait loci, and genome-wide association studies to identify DNA-based genetic variants associating with particular phenotypes. These approaches required large sample sizes in order to detect significant associations.

We developed a novel approach employing the use of erythrocyte microRNA expression profiles from easily accessible peripheral blood shown to demonstrate abundant, diverse, and disease-specific microRNA expression profiles in a pilot study where samples from normal erythrocytes or from anemia disorders grouped into their respective types simply based on microRNA expression.

Since erythrocytes do not contain DNA or larger RNAs, the RNA extracted from these cells is enriched for microRNAs, therefore only a small amount is needed for robust analysis. Erythrocytic microRNA expression can give insight to the total molecular picture of the life of the red blood cell and further illustrate temporal, developmental, stress-responsive, and otherwise functionally meaningful relationships.

The use of erythrocytic microRNA expression profiles is thus a tool which can be used to further identify novel disease modifiers and potential therapeutic targets.  We published a key protocol paper and applied these methods in large and small scale form in the study of anemia disorders including paroxysmal nocturnal hemoglobinuria and Sickle Cell Disease.  

Translational: erythrocyte microRNA profiling leads to promising mechanism/therapeutic target for patients with sickle cell disease

These methods were used in profiling microRNA expression in erythroid progenitor cells from Sickle Cell patients and we identified a promising mechanism to target for therapeutics.  It has since been shown that activation of the nuclear factor erythroid 2–related factor 2 (NRF2) antioxidant response element signaling pathway in erythroid lineage cells, as well as myeloid cells and endothelial cells, differentially contribute to the amelioration of Sickle Cell Disease, and numerous studies have gone on to show that the application of Nrf2 inducers increases γ-globin activity and fetal hemoglobin, alleviating sickle cell retinopathy, sickling, hemolysis, endothelial inflammation, and other promising clinical therapeutic endpoints.

MIR-144-mediated NRF2 gene silencing inhibits fetal hemoglobin expression in sickle cell disease (Exp Hematol 2019), Nrf2 activation in myeloid cells and endothelial cells differentially mitigates sickle cell disease pathology in mice (Blood Adv 2019), Dimethyl fumarate increases fetal hemoglobin, provides heme detoxification, and corrects anemia in sickle cell disease (2017), Monomethylfumarate induces γ-globin expression and fetal hemoglobin production in cultured human retinal pigment epithelial (RPE) and erythroid cells, and in intact retina (2014)