Gene Therapy to Cure HIV: Where to from Here?

Engineered Zinc Finger Protein Targeting 2LTR Inhibits HIV Integration in Hematopoietic Stem and Progenitor Cell-Derived Macrophages: In Vitro Study

Human hematopoietic stem/progenitor cell (HSPC)-based gene therapy is a promising direction for curing HIV-1-infected individuals. The zinc finger protein (2LTRZFP) designed to target the 2-LTR-circle junction of HIV-1 cDNA was previously reported as an intracellular antiviral molecular scaffold that prevents HIV integration. Here, we elucidate the efficacy and safety of using 2LTRZFP in human CD34⁺ HSPCs. We transduced 2LTRZFP which has the mCherry tag (2LTRZFPmCherry) into human CD34⁺ HSPCs using a lentiviral vector. The 2LTRZFPmCherry-transduced HSPCs were subsequently differentiated into macrophages. The expression levels of pro-apoptotic proteins of the 2LTRZFPmCherry-transduced HSPCs showed no significant difference from those of the non-transduced control. Furthermore, the 2LTRZFPmCherry-transduced HSPCs were successfully differentiated into mature macrophages, which had normal phagocytic function. The cytokine secretion assay demonstrated that 2LTRZFPmCherry-transduced CD34⁺ derived macrophages promoted the polarization towards classically activated (M1) subtypes. More importantly, the 2LTRZFPmCherry transduced cells significantly exhibited resistance to HIV-1 integration in vitro. Our findings demonstrate that the 2LTRZFPmCherry-transduced macrophages were found to be functionally and phenotypically normal, with no adverse effects of the anti-HIV-1 scaffold. Our data suggest that the anti-HIV-1 integrase scaffold is a promising antiviral molecule that could be applied to human CD34⁺ HSPC-based gene therapy for AIDS patients.

Research and Clinical Significance of the Differentially Expressed Genes TP63 and LMO4 in Human Immunodeficiency Virus-Related Penile Squamous Cell Carcinoma

To study the differential gene expression and clinical significance in human immunodeficiency virus-infected individuals (HIVIIs) with penile squamous cell carcinoma. At our hospital from 2019 to 2020, we selected six samples of HIV-related penile squamous cell carcinoma for the experimental group and six samples of non-HIV-related penile squamous cell carcinoma for the control group. Transcriptome sequencing of sample mRNAs was performed by high-throughput sequencing. Differential gene expression analysis, differential Gene Ontology (GO) enrichment analysis and differential Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were carried out, and the reads per kilobase per million reads (RPKM) value was used as a measure of gene expression. A total of 2418 differentially expressed genes were obtained, of which 663 were upregulated and 1755 were downregulated (absolute value of logFC >1 and p value <.05). On the basis of the significance of the GO enrichment analysis, we found that the tumor protein p63 (TP63) gene was significantly upregulated and that the LIM domain only 4 (LMO4) gene was significantly downregulated in the experimental group compared with the control group. KEGG pathway analysis of the differentially expressed genes revealed that DNA replication was the most significant pathway associated with the upregulated genes and cell adhesion molecule (CAM) metabolism was the most significant pathway associated with the downregulated genes. The gene expression profiles of HIV-related penile squamous cell carcinoma and non-HIV-related penile squamous cell carcinoma are significantly different and involve significant GO enrichment and KEGG metabolic pathways, and this is very meaningful for the study of non-AIDS-defining cancers (NADCs). Differential expression of genes may be an important target for the prevention of penile squamous cell carcinoma in HIVIIs.

The Daunting Economics of Therapeutic Genome Editing

There is no shortage of enthusiasm for the clinical potential of CRISPR-based genome editing: many life-changing cures appear to be just around the corner. However, as mature genetic therapies reach the market, it seems that million-dollar price tags are the new normal. Several factors contribute to the extreme pricing of next-generation medicines, including the need to recoup development costs, the undeniable value of these powerful therapies, and the inherent technical challenges of manufacture and delivery. CRISPR technology has been hailed as a great leveler and a democratizing force in biomedicine. But for this principle to hold true in clinical contexts, therapeutic genome editing must avoid several pitfalls that could substantially limit access to its transformative potential, especially in the developing world.

Clinical applications of CRISPR-based genome editing and diagnostics

Clustered regularly interspaced short palindromic repeats (CRISPR)-driven genome editing has rapidly transformed preclinical biomedical research by eliminating the underlying genetic basis of many diseases in model systems and facilitating the study of disease etiology. Translation to the clinic is under way, with announced or impending clinical trials utilizing ex vivo strategies for anticancer immunotherapy or correction of hemoglobinopathies. These exciting applications represent just a fraction of what is theoretically possible for this emerging technology, but many technical hurdles must be overcome before CRISPR-based genome editing technology can reach its full potential. One exciting recent development is the use of CRISPR systems for diagnostic detection of genetic sequences associated with pathogens or cancer. We review the biologic origins and functional mechanism of CRISPR systems and highlight several current and future clinical applications of genome editing.

Modeling Anti-HIV-1 HSPC-Based Gene Therapy in Humanized Mice Previously Infected with HIV-1

Investigations of anti-HIV-1 human hematopoietic stem/progenitor cell (HSPC)-based gene therapy have been performed by HIV-1 challenge after the engraftment of gene-modified HSPCs in humanized mouse models. However, the clinical application of gene therapy is to treat HIV-1-infected patients. Here, we developed a new method to investigate an anti-HIV-1 HSPC-based gene therapy in humanized mice previously infected with HIV-1. First, humanized mice were infected with HIV-1. When plasma viremia reached >10⁷ copies/mL 3 weeks after HIV-1 infection, the mice were myeloablated with busulfan and transplanted with anti-HIV-1 gene-modified CD34⁺ HSPCs transduced with a lentiviral vector expressing two short hairpin RNAs (shRNAs) against CCR5 and HIV-1 long terminal repeat (LTR), along with human thymus tissue under the kidney capsule. Anti-HIV-1 vector-modified human CD34⁺ HSPCs successfully repopulated peripheral blood and lymphoid tissues in HIV-1 previously infected humanized mice. Anti-HIV-1 shRNA vector-modified CD4⁺ T lymphocytes showed selective advantage in HIV-1 previously infected humanized mice. This new method will be useful for investigations of anti-HIV-1 gene therapy when testing in a more clinically relevant experimental setting.