Human Gene Therapy Methods最新文献

The β-hemoglobinopathies sickle cell anemia and β-thalassemia are the focus of many gene-therapy studies. A key disease parameter is the abundance of globin chains because it indicates the level of anemia, likely toxicity of excess or aberrant globins, and therapeutic potential of induced or exogenous β-like globins. Reversed-phase high-performance liquid chromatography (HPLC) allows versatile and inexpensive globin quantification, but commonly applied protocols suffer from long run times, high sample requirements, or inability to separate murine from human β-globin chains. The latter point is problematic for in vivo studies with gene-addition vectors in murine disease models and mouse/human chimeras. This study demonstrates HPLC-based measurements of globin expression (1) after differentiation of the commonly applied human umbilical cord blood-derived erythroid progenitor-2 cell line, (2) in erythroid progeny of CD34⁺ cells for the analysis of clustered regularly interspaced short palindromic repeats/Cas9-mediated disruption of the globin regulator BCL11A, and (3) of transgenic mice holding the human β-globin locus. At run times of 8 min for separation of murine and human β-globin chains as well as of human γ-globin chains, and with routine measurement of globin-chain ratios for 12 nL of blood (tested for down to 0.75 nL) or of 300,000 in vitro differentiated cells, the methods presented here and any variant-specific adaptations thereof will greatly facilitate evaluation of novel therapy applications for β-hemoglobinopathies.

Lung cancer, caused mainly by smoking, is one of the most prevalent diseases in China, resulting in high mortality rates. The increasing incidence of chronic disease due to lung cancer places a huge burden on the welfare and cost to the Chinese society. Amplification of the fibroblast growth factor receptor 1 (FGFR1) is associated with high incidence and mortality in lung cancer patients. FGFR1 signaling is implicated in oncogenic traits such as proliferation, cell survival, angiogenesis, and migration. Targeting FGFR1 and its ligand basic FGF (bFGF) is a key step forward in developing new therapies for this crippling disease. Lung adenocarcinoma is the most common subtype of non-small-cell lung cancer. In this study, A549, a lung adenocarcinoma cell line widely used in vitro as a model for drug metabolism and as a transfection host, was used to study FGFR1. A stable lentiviral FGFR1 over-expression system in lung cancer cells is described for the study of anti-lung cancer drug candidates targeting FGFR1. Ligand binding to FGFR1 activates the PI3K/Akt/mTOR signaling pathway and increases adhesion, invasion, and migration in this model. Using a unique FGF monoclonal antibody developed in the laboratory, the overactive PI3K pathway was effectively blocked, abrogating the negative metastatic signaling pathways in lung cancer cells. Importantly, this model provides an effective and simple screening kit for anti-FGF1 drug compounds for lung cancer treatment and a tool for understanding the molecular mechanisms of the FGFR1 signaling pathway in lung cancer. Furthermore, this toolkit based on a FGFR1 lentiviral construct model is transferrable to study FGFR1 signaling in any type of cancer cell.

Lentiviral vectors are used in laboratories around the world for in vivo and ex vivo delivery of gene therapies, and increasingly clinical investigation as well as preclinical applications. The third-generation lentiviral vector system has many advantages, including high packaging capacity, stable gene expression in both dividing and post-mitotic cells, and low immunogenicity in the recipient organism. Yet, the manufacture of these vectors is challenging, especially at high titers required for direct use in vivo, and further challenges are presented by the process of translating preclinical gene therapies toward manufacture of products for clinical investigation. The goals of this paper are to report the protocol for manufacturing high-titer third-generation lentivirus for preclinical testing and to provide detailed information on considerations for translating preclinical viral vector manufacture toward scaled-up platforms and processes in order to make gene therapies under Good Manufacturing Practice that are suitable for clinical trials.

Vesicular stomatitis virus G glycoprotein (VSVg) is extensively used for retroviral and lentiviral vector (LV) pseudotyping. However, VSVg pseudotyped vectors are serum inactivated, blocking the in vivo gene delivery. Several strategies have been employed to prevent complement inactivation, including chemical and genetic envelope modifications. This study employed the streptococcal albumin-binding domain (ABD) to generate a construct to express ABD as a glycosylphosphatidylinositol-anchored protein. LV particles bearing ABD are able to bind bovine and human serum albumin in vitro. Neither the lentiviral vector production titer nor the in vitro transduction was affected by the ABD display. The study demonstrated that ABD-bearing LVs are protected from human complement inactivation. More importantly, intravenous administration demonstrated that the presence of ABD significantly reduces lentivector sequestration in liver and bone-marrow cells. Therefore, the use of ABD represents an improvement for in vivo gene therapy applications. The results strongly point to ABD display as a universal strategy to increase the in vivo efficacy of different viral vectors.

Lentiviral vectors (LV) represent a key tool for gene and cell therapy applications. The production of these vectors in sufficient quantities for clinical applications remains a hurdle, prompting the field toward developing suspension processes that are conducive to large-scale production. This study describes a LV production strategy using a stable inducible producer cell line. The HEK293 cell line employed grows in suspension, thus offering direct scalability, and produces a green fluorescent protein (GFP)-expressing lentiviral vector in the 10⁶ transduction units (TU)/mL range without optimization. The stable producer cell line, called clone 92, was derived by stable transfection from a packaging cell line with a plasmid encoding the transgene GFP. The packaging cell line expresses all the other necessary components to produce LV upon induction with cumate and doxycycline. First, the study demonstrated that LV production using clone 92 is scalable from 20 mL shake flasks to 3 L bioreactors. Next, two strategies were developed for high-yield LV production in perfusion mode using acoustic cell filter technology in 1-3 L bioreactors. The first approach uses a basal commercial medium and perfusion mode both pre- and post-induction for increasing cell density and LV recovery. The second approach makes use of a fortified medium formulation to achieve target cell density for induction in batch mode, followed by perfusion mode after induction. Using these perfusion-based strategies, the titer was improved to 3.2 × 10⁷ TU/mL. As a result, cumulative functional LV titers were increased by up to 15-fold compared to batch mode, reaching a cumulative total yield of 8 × 10¹⁰ TU/L of bioreactor culture. This approach is easily amenable to large-scale production and commercial manufacturing.

Transduction of hematopoietic stem and progenitor cells (HSPCs) with lentiviral vectors (LVs) constitutes a new therapeutic option for the treatment of various monogenic diseases affecting the lymphohematopoietic system. The development of detailed preclinical studies of gene therapy in animal disease models constitutes an essential step in expanding the application of gene therapy in a wide variety of inherited and acquired diseases. Here we describe an efficient protocol to transduce HSPCs from wild-type and Fanconi anemia mice with either gene-marking or therapeutic LVs. In this protocol, purified lineage^-, Sca-1⁺, c-Kit⁺ bone marrow cells were transduced in vitro for a short period of time under conditions that facilitated efficient transduction of HSPCs capable of engrafting in transplanted recipients.

Redirected T cells genetically modified with a chimeric antigen receptor (CAR) have induced spectacular remissions of refractory leukemia/lymphoma in early phase trials, attracting interest to use CAR T cells in a variety of other applications including solid cancer and nonmalignant diseases. However, extensive preclinical explorations demand highly effective and robust procedures for the genetic modification of blood T cells; the same applies for engineering with a recombinant T cell receptor. We present laboratory procedures in a step-by-step protocol to engineer human and mouse T cells with a CAR by γ-retro- or lentiviral transduction for further preclinical testing.

Hereditary pulmonary alveolar proteinosis (hPAP) is a rare disorder of pulmonary surfactant accumulation and hypoxemic respiratory failure caused by mutations in CSF2RA (encoding the granulocyte/macrophage colony-stimulating factor [GM-CSF] receptor α-chain [CD116]), which results in reduced GM-CSF-dependent pulmonary surfactant clearance by alveolar macrophages. While no pharmacologic therapy currently exists for hPAP, it was recently demonstrated that endotracheal instillation of wild-type or gene-corrected mononuclear phagocytes (pulmonary macrophage transplantation [PMT]) results in a significant and durable therapeutic efficacy in a validated murine model of hPAP. To facilitate the translation of PMT therapy to human hPAP patients, a self-inactivating (SIN) lentiviral vector was generated expressing a codon-optimized human CSF2RA-cDNA driven from an EF1α short promoter (Lv.EFS.CSF2RA^coop), and a series of nonclinical efficacy and safety studies were performed in cultured macrophage cell lines and primary human cells. Studies in cytokine-dependent Ba/F3 cells demonstrated efficient transduction, vector-derived CD116 expression proportional to vector copy number, and GM-CSF-dependent cell survival and proliferation. Using a novel cell line constructed to express a normal GM-CSF receptor β subunit and a dysfunctional α subunit (due to a function-altering CSF2RA^G196R mutation) that reflects the macrophage disease phenotype of hPAP patients, it was demonstrated that Lv.EFS.CSF2RA^coop transduction restored GM-CSF receptor function. Further, Lv.EFS.CSF2RA^coop transduction of healthy primary CD34⁺ cells did not adversely affect cell proliferation or affect the cell differentiation program. Results demonstrate Lv.EFS.CSF2RA^coop reconstituted GM-CSF receptor α expression, restoring GM-CSF signaling in hPAP macrophages, and had no adverse effects in the intended target cells, thus supporting testing of PMT therapy of hPAP in humans.

Viruses have evolved specialized molecular mechanisms to transfer their genome efficiently into host cells. Viruses can be repurposed into viral vectors to achieve controlled gene transfer to desired cells. One of the most popular classes of vectors, lentiviral vectors (LVs), transduce mammalian cells efficiently. LVs are pseudotyped with various heterologous viral envelopes to alter their tropism. While the most common example is the envelope glycoprotein from vesicular stomatitis virus (VSVG), many other viral proteins have also been used. Pseudotyping LVs with a diverse set of naturally occurring or engineered viral envelopes has allowed targeted transduction of specific cell types. Many exciting studies are further uncovering new specificities and shortcomings of pseudotyped LVs. These studies will expand the toolbox to make LVs that cater to the specific requirements of transduction. This review provides a comprehensive overview of various viral envelope pseudotypes used with LVs, their specificities, advantages, and drawbacks.

Adenoviral vector production for therapeutic applications is a well-established routine process. However, current methods for measurement of adenovirus particle titers as a quality characteristic require highly purified virus preparations. While purified virus is typically obtained in the last step of downstream purification, rapid and reliable methods for adenovirus particle quantification in intermediate products and crude lysates to allow for optimization and validation of cell cultures and intermediate downstream processing steps are currently not at hand. Light scattering is an established process to measure virus particles' size, though due to cell impurities, adequate quantification of adenovirus particles in cell lysates by light scattering has been impossible until today. This report describes a new method using light scattering to measure virus concentration in nonpurified cell lysates. Here we report application of light scattering, a routine method to measure virus particle size, to virus quantification in enzymatically conditioned crude lysates. Samples are incubated with phospholipase A2 and benzonase and filtered through a 0.22 μm filter cartridge prior to quantification by light scattering. Our results show that this treatment provides a precise method for fast and easy determination of total adenovirus particle numbers in cell lysates and is useful to monitor virus recovery throughout all downstream processing.