Engineering Globin Gene Expression

Abstract

Hemoglobinopathies, including sickle cell disease and thalassemia, are among the most common inherited genetic diseases worldwide. Due to the relative ease of isolating and genetically modifying hematopoietic stem and progenitor cells, recent gene editing and gene therapy strategies have progressed to clinical trials with promising outcomes; however, challenges remain and necessitate the continued exploration of new gene engineering and cell transplantation protocols. Current gene engineering strategies aim at reactivating the expression of the fetal γ-globin genes in adult erythroid cells. The γ-globin proteins exhibit anti-sickling properties and can functionally replace adult β-globin. Here, we describe and compare the current genetic engineering procedures that may develop into safe and efficient therapies for hemoglobinopathies in the near future.

Precise and error-prone CRISPR-directed gene editing activity in human CD34+ cells varies widely among patient samples

“…Of the many inherited diseases amenable to gene editing, SCD holds a certain fascination for workers in the field since a solution, single-base correction, seems logical and attainable [ 27 ]. While impressive levels of HDR and genetic conversion have been reported, they are usually not robust, perhaps due to the heterogeneous population of cells and the reaction conditions used in the targeting experiments.…”

Genome editing of HBG1 and HBG2 to induce fetal hemoglobin

“…Genome editing of patient HSCs by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 nucleases represents a promising approach for genetic correction of b-hemoglobinopathies. [4][5][6] These nucleases introduce targeted DNA double-stranded breaks (DSBs) that can be exploited therapeutically through 2 general cellular DNA damage repair strategies. First, HBB mutations can be corrected via homologydirected repair (HDR).…”

Genome-edited adult stem cells: Next-generation advanced therapy medicinal products

“…The most successful strategies are aimed at reactivating fetal γ-globin gene expression by disrupting the negative regulatory region of the γ-globin gene. 59,60 These were the first human GE strategies to be investigated in clinical trials using CRISPR/CAS9 (CTX001, NCT03745287) and later ZFNs (ST-400; NCT03432364) for the treatment of β-thalassemia and SCD. New clinical trials have been approved for these diseases using…”