Genetic Manipulation Strategies for β-Thalassemia: A Review

Abstract

Thalassemias are monogenic hematologic diseases that are classified as α- or β-thalassemia according to its quantitative abnormalities of adult α- or β-globin chains. β-thalassemia has widely spread throughout the world especially in Mediterranean countries, the Middle East, Central Asia, India, Southern China, and the Far East as well as countries along the north coast of Africa and in South America. The one and the only cure for β-thalassemia is allogenic hematopoietic stem cell transplantations (HSCT). Nevertheless, the difficulty to find matched donors has hindered the availability of this therapeutic option. Therefore, this present review explored the alternatives for β-thalassemia treatment such as RNA manipulation therapy, splice-switching, genome editing and generation of corrected induced pluripotent stem cells (iPSCs). Manipulation of β-globin RNA is mediated by antisense oligonucleotides (ASOs) or splice-switching oligonucleotides (SSOs), which redirect pre-mRNA splicing to significantly restore correct β-globin pre-mRNA splicing and gene product in cultured erythropoietic cells. Zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) are designer proteins that can alter the genome precisely by creating specific DNA double-strand breaks. The treatment of β-thalassemia patient-derived iPSCs with TALENs have been found to correct the β-globin gene mutations, implying that TALENs could be used as a therapy option for β-thalassemia. Additionally, CRISPR technologies using Cas9 have been used to fix mutations in the β-globin gene in cultured cells as well as induction of hereditary persistence of fetal hemoglobin (HPFH), and α-globin gene deletions have proposed a possible therapeutic option for β-thalassemia. Overall, the accumulated research evidence demonstrated the potential of ASOs-mediated aberrant splicing correction of β-thalassemia mutations and the advancements of genome therapy approaches using ZFNs, TALENs, and CRISPR/Cas9 that provided insights in finding the permanent cure of β-thalassemia.

Impact of α-Globin Gene Expression and α-Globin Modifiers on the Phenotype of β-Thalassemia and Other Hemoglobinopathies: Implications for Patient Management

“…The clinical relevance of the inbalanced expression of α-globin versus β-globin genes is strongly in agreement with data obtained by genome editing approaches, as is summarized in Figure 2. Genome editing (GE) can be considered among the most promising strategies to correct hereditary alterations in a variety of monogenic diseases, including hematopoietic pathologies [34,35]. Figure 2 depicts how CRISPR-Cas9 gene editing can be applied to βthalassemia [34,[36][37][38][39][40][41][42][43][44].…”

“…The AHSP gene is located on human chromosome 16 (Chr16p11.2). It is Genome editing (GE) can be considered among the most promising strategies to correct hereditary alterations in a variety of monogenic diseases, including hematopoietic pathologies [34,35]. Figure 2 depicts how CRISPR-Cas9 gene editing can be applied to β-thalassemia [34,[36][37][38][39][40][41][42][43][44].…”

Oncology Breakthroughs to A New Pace of Precision Diagnostics and Therapeutics

“…Messenger RNA can also deliver gene editing tools such as CRISPR-Cas9 to cells and tissues, making it possible to correct deleterious mutations that cause genetic disorders. For example, mRNA-delivered gene editing tools can eliminate aberrant splicing sites that cause beta-thalassemia [41]. It can also deliver gene editing tools to cancer cells, enabling precise genomic modifications that make the cells more vulnerable to immune attack.…”

Phát Hiện Người Mang Gen Bệnh -Thalassemia Bằng Kỹ Thuật Giải Trình Tự Gen Sanger

“…Các đột biến gen HBB tại chỗ cắt nối kích hoạt các vị trí cắt nối sai lệch làm giảm hiệu quả của cắt nối mRNA bình thường, dẫn đến sản sinh chuỗi βglobin không có chức năng làm phát sinh bệnh -thalassemia. 9 Tất cả các trường hợp phát hiện HbE đều có đột biến CD26. Điều này cho thấy độ nhạy của phương pháp điện di huyết sắc tố đạt 100% đối với HbE.…”

“…Đột biến Cytosine thành Thymine ở nucleotide 654 của gen HBB ở intron 2 (IVS-II-654) là một trong những đột biến phổ biến nhất gây ra bệnh thalassemia ở người Trung Quốc và Đông Nam Á ảnh hưởng đến sự cắt nối gen HBB ở giai đoạn tiền mRNA, đột biến IVS-I-1 cũng làm bất hoạt vị trí cắt nối đầu 5' làm cho quá trình cắt nối bị RNA bị gián đoạn. 9 Đột biến -28 là đột biến ở vùng khởi động làm giảm sự gắn yếu tố phiên mã của hộp TATA, từ đó làm giảm biểu hiện RNA của HBB.…”