Lentiviral Transfer of γ-Globin with Fusion Gene NUP98-HOXA10HD Expands Hematopoietic Stem Cells and Ameliorates Murine β-Thalassemia

Biotechnological Advances in Gene Therapy of Hematopoietic Stem Cells: Systematic Review and Meta-Analysis

Gene therapy (GT) has emerged as a promising treatment option for disorders in the hematopoietic system, particularly primary immunodeficiencies (PID). Hematopoietic stem cells (HSCs) have gained attention due to their ability to support long-term hematopoiesis. In this study, we present a summary of research evaluating the most effective method of gene editing in HSCs for translational medicine. We conducted a systematic literature search in various databases, including Cochrane, LILACs, SciELO, and PubMed (MEDLINE), covering the period from January 1989 to June 10, 2023. The aim of this study was to identify articles that assessed the efficiency of gene editing in HSCs and clinical trials focusing on PID. Our research protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number CRD42022349850). Of the 470 studies identified in our search, 77 met the inclusion criteria. Among these, 61 studies were included in strategy 1 (gene therapy using HSC [GT-HSC]) of the systematic review (SR). We performed a meta-analysis on 17 of these studies. In addition, 16 studies were categorized under strategy 2 (clinical trials for PID). While clinical trials have demonstrated the potential benefits of GT-HSC, the safety and efficacy of gene editing still pose significant challenges. Various viral and nonviral approaches for gene delivery have been explored in basic and clinical research, with viral vectors being the most commonly used method in HSC therapeutics. Although promising, recent technologies such as CRISPR/Cas are not yet ready for efficient long-term restoration of the immune system as a whole.

Comparative targeting analysis of KLF1, BCL11A, and HBG1/2 in CD34+ HSPCs by CRISPR/Cas9 for the induction of fetal hemoglobin

β-hemoglobinopathies are caused by abnormal or absent production of hemoglobin in the blood due to mutations in the β-globin gene (HBB). Imbalanced expression of adult hemoglobin (HbA) induces strong anemia in patients suffering from the disease. However, individuals with natural-occurring mutations in the HBB cluster or related genes, compensate this disparity through γ-globin expression and subsequent fetal hemoglobin (HbF) production. Several preclinical and clinical studies have been performed in order to induce HbF by knocking-down genes involved in HbF repression (KLF1 and BCL11A) or disrupting the binding sites of several transcription factors in the γ-globin gene (HBG1/2). In this study, we thoroughly compared the different CRISPR/Cas9 gene-disruption strategies by gene editing analysis and assessed their safety profile by RNA-seq and GUIDE-seq. All approaches reached therapeutic levels of HbF after gene editing and showed similar gene expression to the control sample, while no significant off-targets were detected by GUIDE-seq. Likewise, all three gene editing platforms were established in the GMP-grade CliniMACS Prodigy, achieving similar outcome to preclinical devices. Based on this gene editing comparative analysis, we concluded that BCL11A is the most clinically relevant approach while HBG1/2 could represent a promising alternative for the treatment of β-hemoglobinopathies.

Fetal hemoglobin and F-cell variance in mobilized CD34+ cell-transplanted rhesus monkeys

Elevated fetal hemoglobin (HbF) is associated with reduced severity of sickle cell disease. Therefore, γ-globin protein levels and F-cell (HbF-positive red blood cell) percentages are used for estimation of clinical benefit. Here, we monitored transplantation-related changes in HbF and F-cell percentages for rhesus macaques (Macaca mulatta) following total body irradiation or busulfan conditioning prior to CD34⁺ cell transplantation. HbF protein expression peaked in the first 4-9 weeks posttransplant (0.99%-2.53%), and F-cells increased in the first 6-17 weeks posttransplant (8.7%-45.3%). HbF and F-cell ratios gradually decreased and stabilized to levels similar to those of control animals (1.96 ± 1.97% for F cells and 0.49 ± 0.19% γ-globin expression) 4-7 months post-transplant. These findings confirm and expand on previous reports of transient induction in HbF and F-cell percentages in rhesus macaques following CD34⁺ cell transplantation, an observation that must be taken into consideration when evaluating therapeutic strategies that aim to specifically elevate HbF expression, which are currently in clinical development.

Modified conditioning regimen improves outcomes of unrelated donor peripheral blood stem cell transplantation for β-thalassaemia major patients

BACKGROUND

The objective of this study was to evaluate the feasibility of a modified conditioning regimen for the treatment of patients with β-thalassaemia major (TM), using unrelated donor peripheral blood stem cell transplantation (UD-PBSCT).

METHODS

A modified conditioning regimen based on intravenous busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin was performed in 50 consecutive childhood patients with β-TM and a median age of 4.6 years (range, 2-12 years). According to Pesaro's classification, three classes of risk are identified using the criteria of degree of hepatomegaly, portal fibrosis, and quality of the chelation treatment. Patients with three adverse criteria constituted class III, none of the adverse criteria constituted class I, and one or two of the adverse criteria formed class II. Ten patients were class I, 36 class II, and four class III. All patients were transplanted with UDs containing 37 of 10/10 human leukocyte antigen (HLA)-matched pairs, 11 of 9/10 matched pairs, and two of 8/10 matched pairs. The median follow-up was 36 months (range, 9-96 months).

RESULTS

All patients successfully achieved engraftment, two of whom developed persistent thrombocytopaenia. The incidence of acute graft-versus-host disease (aGVHD) grade III-IV and chronic graft-versus-host disease (cGVHD) were 12% and 8%, respectively. However, 8.3% of HLA-matched and 15.4% of HLA-mismatched patients developed aGVHD. The incidence of severe bacterial infections and fungal pneumonia was 12% and 20%, respectively. The 3-year overall survival, disease-free survival, graft rejection, and transplant-related mortality were 94%, 92%, 2%, and 6%, respectively.

CONCLUSION

This modified conditioning protocol effectively improved outcomes of UD-PBSCT for patients with β-TM.

Recent challenges and advances in genetically-engineered cell therapy

Cells naturally sense and actively response to their environment. Cell-therapy has long been studied and shown therapeutic effects in various diseases. However, several hurdles should be overcome to improve cell-based therapy. Gene delivery-mediated cellular modification has shown improvement of cell function by obstacle gene silencing and therapeutic gene expression. Especially, CRISPR/Cas9-mediated genome editing is a very promising method for gene modification. In this review, we describe the recent advances in genetic modification for cell therapy. Stem cells are still promising source of cell therapy due to their self-renewal character and differentiation potential. Immune cells regulate the inflammatory response and immunization, which inspired various cell therapy using immune-regulatory cells. Conclusively, we emphasize the need to develop gene-modification-based cell therapy as potent future treatment.

The roles of the nuclear pore complex in cellular dysfunction, aging and disease

The study of the Nuclear Pore Complex (NPC), the proteins that compose it (nucleoporins), and the nucleocytoplasmic transport that it controls have revealed an unexpected layer to pathogenic disease onset and progression. Recent advances in the study of the regulation of NPC composition and function suggest that the precise control of this structure is necessary to prevent diseases from arising or progressing. Here we discuss the role of nucleoporins in a diverse set of diseases, many of which directly or indirectly increase in occurrence and severity as we age, and often shorten the human lifespan. NPC biology has been shown to play a direct role in these diseases and therefore in the process of healthy aging.