Lentivirus-mediated Gene Transfer Research Articles

HKLK alleviates myocardial fibrosis in mice with viral myocarditis.

Myocardial fibrosis is the most serious complication of viral myocarditis (VMC). This study aimed to investigate the therapeutic benefits and underlying mechanisms of lentivirus-mediated human tissue kallikrein gene transfer in myocardial fibrosis in VMC mice. We established VMC mouse model via intraperitoneal injection with Coxsackie B3 virus. The effect was then assessed after treatment with vehicle, the empty lentiviral vectors (EZ.null), and the vectors expressing hKLK1 (EZ.hKLK1) via tail vein injection for 30 days, respectively. The results showed that administering EZ.hKLK1 successfully induced hKLK1 overexpression in mouse heart. Compared with EZ.null treatment, EZ.hKLK1 administration significantly reduced the heart/weight ratio, improved cardiac function, and ameliorated myocardial inflammation in VMC mice, suggesting that hKLK1 overexpression alleviates VMC in mice. EZ.hKLK1 administration also significantly abrogated the increased myocardial collagen content, type I/III collagen ratio, TGF-β1 mRNA and protein expression in VMC mice, suggesting that hKLK1 overexpression reduces collagen accumulation and blunts TGF-β1 signaling in the hearts of VMC mice. In conclusion, our results suggest that hKLK1 alleviates myocardial fibrosis in VMC mice, possibly by downregulating TGF-β1 expression.

Establishment of an in vitro Differentiation and Dedifferentiation System of Rat Schwann Cells.

In the peripheral nervous system, Schwann cells are the primary type of glia; their in vitro differentiation and dedifferentiation system has not been described in detail in the literature. Thus, an in vitro differentiation and dedifferentiation system of rat Schwann cells is described in this protocol. These cultures and systems may be used to investigate the morphological and biochemical effects of drug interventions or lentivirus-mediated gene transfer on Schwann cells during differentiation or dedifferentiation. Graphical abstract.

Smoke-induced SAV1 Gene Promoter Hypermethylation Disrupts YAP Negative Feedback and Promotes Malignant Progression of Non-small Cell Lung Cancer.

YAP (gene symbol YAP1) as a potential oncoprotein, is positively correlated with the malignancy of various tumors. However, overexpression of YAP alone in multiple normal tissue cells has failed to induce tumor formation and the underlying mechanism is poorly understood. Herein, we show that YAP activation directly induces transcription of its negative regulator, SAV1, to constitute a negative feedback loop, which plays a vital role in maintaining lung epithelial cell homeostasis and was dysregulated in non-small cell lung cancer (NSCLC). Notably, smoking promotes the hypermethylation of the SAV1 promoter region, which disrupts YAP negative feedback by inactivating the Hippo pathway. Besides, exogenous overexpression of SAV1 can act as a traffic protein, activating the Hippo signaling and concurrently inhibiting the WNT pathway to decrease cancer cell growth. Furthermore, using the lung cancer organoids, we found that lentivirus-mediated SAV1 gene transfer combined with methylation inhibitor and YAP-TEAD inhibitor is a potential feasible clinical medication regimen for the lung cancer patient, especially among the smoking population. Thus, this SAV1 mediated feedback loop provides an efficient mechanism to establish the robustness and homeostasis of YAP regulation and as a potential target of gene therapy for the smoking NSCLC population.

Abstract 10253: Sin3a Gene Delivery Restores Bmpr2 Expression Through Foxk2 in Pulmonary Arterial Endothelial Cells and Inhibits Sugen/Hypoxia-Induced Pah

Background: Pulmonary arterial hypertension (PAH) is a fatal lung disease of multifactorial etiology, with no curative treatment. Several studies have previously suggested that the loss of BMPR2 expression is associated with a severe hemodynamic profile and poor outcomes in PAH patients. Furthermore, preclinical studies showed that the loss of BMPR2 function is sufficient to induce a PAH-like phenotype. Recently, our group showed that SIN3a (Switch-Independent 3) plays a critical role in the epigenetic regulation of BMPR2 expression in human pulmonary arterial smooth muscle cells (hPASMC). However, our preliminary data suggested that SIN3a regulates BMPR2 expression through a different pathway independently of DNA-methylation in human pulmonary arterial endothelial cells (hPAEC). Methods/Results: We found a significant downregulation of SIN3a expression in the PAEC isolated from PAH patients. In hPAEC, our results showed that SIN3a inhibits cell proliferation, migration and upregulates BMPR2 independently of the methylation status by upregulating the FOXK2 transcription factor. Using a loss-of-function approach using a specific shRNA against FOXK2, we found that the loss of FOXK2 expression using a specific shRNA decreased the expression of BMPR2 in hPAECs. Interestingly, we found that SIN3a overexpression in FOXK2-depleted hPAEC restored the expression of BMPR2. Our results also showed that SIN3a regulates hPAEC proliferation in a FOXK2-dependant manner. Mechanistically, we found that SIN3a interacts physically with FOXK2 to promote its nuclear localization. As a result, we also found enrichment in FOXK2 abundance within the BMPR2 promoter by ChIP-qPCR in PAEC. In vivo , our results showed that restoring SIN3a expression by lentivirus-mediated gene transfer significantly decreased SuHx-induced PAH in mice, as illustrated by decreased vascular remodeling, RV hypertrophy (Fulton index, hypertrophic markers, cardiomyocyte size), and RV systolic pressure. Conclusions: Altogether, our study revealed that SIN3a plays a critical role in the regulation of BMPR2 expression through FOXK2. Additionally, our study identifies lung-targeted SIN3a gene therapy as a new promising therapeutic strategy for treating PAH patients.

Immortalization of cells derived from domestic dogs through expressing mutant cyclin-dependent kinase 4, cyclin D1, and telomerase reverse transcriptase.

The online version contains supplementary material available at 10.1007/s10616-021-00504-0.

Safety and Efficacy Trial of Escalation of Plerixafor for Mobilization of CD34+ Hematopoietic Progenitor Cells (HPCs) for Globin Gene Transfer in Patients with Sickle Cell Disease

▪There is presently no curative therapy for SCD other than allogeneic hematopoietic progenitor cell (HPC) transplantation. Incoming trials of autologous gene therapy approaches in patients with sickle cell disease (SCD) include the need of HPCs for gene transduction. However, the use of G-CSF for mobilization of HPCs is contraindicated in this patient population, having resulted in sickle crises and death in some patients.Plerixafor is an inhibitor of the CXCR4 chemokine receptor on HPCs and blocks binding of its ligand, stromal cell-derived factor-1α (SDF-1α). It is FDA-approved at doses of 240 μg/kg subcutaneously in combination with G-CSF for autologous HPC mobilization in non- Hodgkin lymphoma and multiple myeloma patients.We designed a multi center 3+3, phase 1 study of dose escalation of plerixafor for mobilization of HPC in patients with SCD. The primary goal of this trial is to evaluate the safety of, and the optimal dose for the mobilization of HPCs with plerixafor alone. The desired optimal peripheral blood CD34 concentration was set at > 30 cells/μl. Plerixafor was supplied by Sanofi following their approval of the protocol. Because of the ethical considerations, and the risks associated with the mobilization of patients with SCD, the protocol was submitted to, and approved by the FDA; IND 122657. It was registered with ClinicalTrials.gov; identifier: NCT02193191.Fourteen patients with SCD were entered on the study to date, and 13 patients were evaluable. Patients' age was 21-41 years (median 30 years). Patients had a history of SCD complications including vaso-occlusive crises, acute chest syndrome, osteomyelitis, cerebral aneurysm, retinal ischemia, and skin ulcers. Nine patients were on, and 4 patients were off hydroxyurea at the time of accrual on study.Six patients were treated at the first dose level of 80 μg/Kg, three patients at the second dose level of 160 μg/Kg, and to date, four patients at the third dose level of 240 μg/Kg. Two patients developed adverse events of vaso-occlusive crisis, 2 and 4 days following completion of plerixafor at the first and third dose level respectively, requiring increasing the first and third dose cohorts to 6 patients.White blood cell counts (WBC), absolute neutrophil counts (ANC), absolute lymphocyte counts (ALC) (x 10^9/L), CD34+ and CD34+CD38- cell counts were measured at the following time points: 0, 6-12 and 20-24 hours post-treatment with Plerixafor, which allowed to identify the optimal CD34 peak time in SCD patients.The results of peak WBC, ANC and ALC, and fold increase for these counts, as well as CD34+ concentrations (cells/μl), and number of patients achieving a CD34+count > 30 cells/μl are shown in Table 1 for patients at the 3 dose levels. There was a 1.8-2.8 fold increase in WBC and 1.0-2.2 fold increase in ANC at the 3 dose levels, and CD34 concentrations were: 7-132 cells/μl, 27-251 cells/μl and 19-95 cells/μl for the 3 respective dose levels. There were no significant variations in the levels of hemoglobin and platelets.In summary, this is the first trial on the use of plerixafor for HPC mobilization in patients with SCD. Our data in 13 patients support the safety of plerixafor administration at doses of 80, 160 μg/Kg, and 240 μg/Kg, which is especially significant, in view of the prior toxicity associated with G-CSF in this patient population. Plerixafor increased WBC, ANC and ALC to acceptable levels (1.8-2.8 fold), and allowed the mobilization of high numbers of CD34+ cells for 8 of 13 patients treated at the 3 dose levels. This study will allow us to define the optimal conditions for effective globin gene transfer after optimization of lentivirus-mediated globin gene transfer with the TNS9.3.55 vector in an upcoming trial. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Genetically Engineered Regulatory T Cells for Treatment of Graft-Versus-Host-Disease

Graft-versus-host-disease (GVHD) undermines survival and complicates survivorship of recipients of allogeneic hematopoietic stem-cell transplantation (HSCT). Adoptive transfer of natural T regulatory cells (nTregs) expressing the lineage-specific transcription factor FOXP3 has been successfully used to prevent or treat GVHD in humans and mice. However, human applications of propagated nTregs have been hampered by the need for extensive ex vivo expansion to obtain sufficient numbers. Furthermore, such nTregs could lose expression of FOXP3 compromising their suppressive function after adoptive transfer. Therefore, we have developed a method to generate large numbers of engineered Tregs (eTregs) that stably express FOXP3 and show potent immune suppressive functions in vitro and in a mouse model of GVHD.Primary human CD4+ T cells were transduced with a lentiviral construct to co-express FOXP3 and truncated low-affinity nerve growth factor receptor (dLNGFR). The genetically modified T cells were purified using dLNGFR-specific magnetic beads and propagated by cross-linking CD3/CD28 in the presence of IL-2 for two weeks, resulting in a substantial increase in cell number while maintaining stable expression of FOXP3. Flow cytometry demonstrated that ≥90% purified eTregs were CD4+CD25+CD127neg FOXP3+, reminiscent of bona fide Tregs. In addition, the propagated eTregs maintained TCR Vβ diversity and expressed markers associated with Treg function, including CTLA-4, GITR and CD39.The eTregs vigorously suppressed the proliferation of TCR-stimulated allogeneic CD4+ and CD8+ effector T cells in vitro in a dose-dependent fashion. The suppression was superior to FOXP3+ nTregs isolated from peripheral blood mononuclear cells (PBMC) and numerically expanded by cross-linking CD3/CD28 in the presence of IL-2. We stimulated eTregs with phorbol 12-myristate 13-acetate and a Ca2+ ionophore to determine intracellular IL-2 and IFN-γ by flow cytometry. The production of these cytokines was significantly reduced as compared to stimulated control effector T cells. These results indicated that the eTregs were hyporesponsive or anergic, which is consistent with the findings from nTregs by us and others.To determine the therapeutic potential of eTregs, we used a xenogeneic model of GVHD (xGVHD), induced in sublethally irradiated immunocompromised (NSG) mice. We co-infused allogeneic human PBMC with graded numbers of eTregs and nTregs and demonstrated that the eTregs could significantly protect mice from xGVHD-induced weight loss as well as mortality, as compared to untreated control mice (Figure). Of note, fewer numbers of eTregs were needed compared to nTregs to achieve these biological endpoints. Analysis of peripheral blood from the mice demonstrated the engraftment of eTregs with maintained TCR Vβ diversity and histological analyses of tissues showed substantially reduced infiltrations of human CD45+ cells in the colon, liver and bone marrow in eTreg-treated mice as compared to untreated controls. In addition, cytokines such as human TNF-α and IFN-γ, associated with the pathogenesis of human GVHD, were markedly decreased in the plasma of eTreg-treated mice.In summary, we demonstrated that lentivirus-mediated gene transfer of FOXP3/dLNGFR into primary human CD4+ T cells enabled the generation of potent eTregs that were capable of controlling xGVHD in mice. Our results warrant further study in patients after allogeneic HSCT with GVHD. [Display omitted] DisclosuresTu:Intrexon Corporation: Employment, Equity Ownership. Fox:Intrexon Corporation: Employment, Equity Ownership. Ly:Intrexon Corporation: Employment, Equity Ownership. Steinhart:Intrexon Corporation: Employment, Equity Ownership. Laporte:Intrexon Corporation: Employment. Brennan:Intrexon Corporation: Employment, Equity Ownership. Bolinger:Intrexon Corporation: Employment, Equity Ownership. Cooper:Argos Therapeutics: Equity Ownership; AmpliPhi Biosciences: Equity Ownership; Intrexon Corporation: Equity Ownership, Patents & Royalties; Procter & Gamble: Equity Ownership; Targazyme, Inc.: Equity Ownership; Sangamo Biosciences: Patents & Royalties; Immatics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Miltenyi Biotec: Honoraria; Organovo Holdings: Equity Ownership; Ziopharm Oncology: Employment, Equity Ownership, Research Funding; Ferring: Consultancy. Waldner:Intrexon Corporation: Employment, Equity Ownership.

Hermansky-Pudlak Syndrome and Lung Disease: Pathogenesis and Therapeutics.

Hermansky-Pudlak Syndrome (HPS) is a rare, genetic, multisystem disorder characterized by oculocutaneous albinism (OCA), bleeding diathesis, immunodeficiency, granulomatous colitis, and pulmonary fibrosis. HPS pulmonary fibrosis (HPS-PF) occurs in 100% of patients with subtype HPS-1 and has a similar presentation to idiopathic pulmonary fibrosis. Upon onset, individuals with HPS-PF have approximately 3 years before experiencing signs of respiratory failure and eventual death. This review aims to summarize current research on HPS along with its associated pulmonary fibrosis and its implications for the development of novel treatments. We will discuss the genetic basis of the disease, its epidemiology, and current therapeutic and clinical management strategies. We continue to review the cellular processes leading to the development of HPS-PF in alveolar epithelial cells, lymphocytes, mast cells, and fibrocytes, along with the molecular mechanisms that contribute to its pathogenesis and may be targeted in the treatment of HPS-PF. Finally, we will discuss emerging new cellular and molecular approaches for studying HPS, including lentiviral-mediated gene transfer, induced pluripotent stem cells (iPSCs), organoid and 3D-modelling, and CRISPR/Cas9-based gene editing approaches.

Transcriptome Analysis Reveals Downregulation of Urocortin Expression in the Hypothalamo-Neurohypophysial System of Spontaneously Hypertensive Rats.

The chronically increased blood pressure characteristic of essential hypertension represents an insidious and cumulative risk for cardiovascular disease. Essential hypertension is a multifactorial condition, with no known specific aetiology but a strong genetic component. The Spontaneously Hypertensive rat (SHR) shares many characteristics of human essential hypertension, and as such is a commonly used experimental model. The mammalian hypothalamo-neurohypophyseal system (HNS) plays a pivotal role in the regulation of blood pressure, volume and osmolality. In order to better understand the possible role of the HNS in hypertension, we have used microarray analysis to reveal differential regulation of genes in the HNS of the SHR compared to a control normotensive strain, the Wistar Kyoto rat (WKY). These results were validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). One of the genes identified and validated as being downregulated in SHR compared to WKY was that encoding the neuropeptide urocortin (Ucn). Immunohistochemical analyses revealed Ucn to be highly expressed within magnocellular neurons of the PVN and SON, with pronounced localisation in dendritic projections containing oxytocin and vasopressin. When Ucn was overexpressed in the PVN of the SHR by in vivo lentiviral mediated gene transfer, blood pressure was unaffected but there were significant, transient reductions in the VLF spectra of systolic blood pressure consistent with an action on autonomic balance. We suggest that Ucn may act, possibly via dendritic release, to subtly regulate neurohumoral aspects of arterial pressure control.

Transduction of Human T Cell Subsets with Lentivirus.

Lentivirus-mediated gene transfer is an efficient method to introduce a variety of transgenes to human T cells. Here we describe a protocol to transduce human CD4+, CD8+, or CD4+ regulatory T cells. To illustrate the method, we use transduction with lentivirus encoding an HLA-A2-specific chimeric antigen receptor (CAR) and a transduction marker as an example. Methods to isolate, transduce, purify, and expand CD4+ and CD8+ T cells as well as regulatory T cells are provided. We also describe how to carry out cytotoxicity or suppression assays to assess the function of the resulting CAR T cell or CAR regulatory T cells, respectively.

Erythroid Specificity and Safety of Globin-Encoding Lentiviral Vectors

The beta-thalassemias and sickle cell disease are the most common monogenic inherited blood disorders, both arising from mutations affecting the beta-globin locus. Recent clinical trials utilizing lentiviral-mediated beta-globin gene transfer in autologous CD34+ cells have shown encouraging results in patients with non-beta-zero thalassemias and sickle cell anemia. A case report of insertional mutagenesis in a beta-thalassemia patient resulted in a prolonged clonal expansion that eventually regressed without progressing to leukemic transformation. Nonetheless, this occurrence and the need to insert multiple vector copies per cell when using globin vectors that provide insufficient globin expression to achieve curative responses from a single integrated copy per cell, raise some questions about the erythroid specificity and safety of globin vectors. We thus found it imperative to investigate globin vector expression in hematopoietic progenitors and in non-erythroid cells. To this end, we investigated what regulatory elements, including locus control region (LCR) hypersensitive sites (HS) and others, achieve the highest beta-globin expression per vector copy while at the same time minimizing non-erythroid transcriptional activity. We developed an invivo assay to track the enhancer/promoter activity of different HS elements in hematopoietic progenitor and differentiated cell subsets. We designed lentiviral vectors expressing hrGFP under the control of a short β-globin promoter (137bp) controlled by a set of LCR HS elements and/or a novel biliverdin (BLV) enhancer. Analysis of hrGFP expression in bone marrow cells derived from C57BL6 mice transplanted with transduced syngeneic bone marrow cells revealed that many of the vectors encompassing elements thought to encode erythroid-specific elements were in fact expressed in long term-HSC (LT-HSC), short term-HSC (ST-HSC), multipotent progenitors (MPP), pre-GM, Granulocyte/macrophage progenitors (GMP) and megakaryocyte progenitors (MKP). These findings confirmed that ectopically integrated erythroid regulatory elements can serve as transcriptional enhancers in non-erythroid cells. This transcriptional leakiness was confirmed in therapeutic globin vectors harboring a combination of LCR elements. To avoid these effects, we flanked the globin transcription unit with a small human enhancer-blocking element called A1, kindly provided by the late George Stamatoyannopoulos (Liu, M. et al. 2015). The insulated vector showed markedly reduced non-erythroid expression in non-erythroid cells including ST-HSC, MPP, Pre-GM and GMP. Expression in mature erythroid cells was unchanged. Our findings underscore the benefits of selecting lineage-specific regulatory elements with the least lineage promiscuity for therapeutic vectors, with the eventual addition of enhancer-blocking elements. Based on these results, we are now investigating new globin expression vectors with optimal combination of HS elements. Such novel globin vectors should minimize the risk of oncogene trans-activation in hematopoietic progenitor cells and therefore improve the safety of globin gene therapy while providing lineage-specific high-level expression. Disclosures Sadelain: Mnemo: Patents & Royalties; Fate Therapeutics: Patents & Royalties, Research Funding; Atara: Patents & Royalties, Research Funding; Takeda: Patents & Royalties, Research Funding; Minerva: Other: Biotechnologies , Patents & Royalties.

Generation of Powerful Human Tolerogenic Dendritic Cells by Lentiviral-Mediated IL-10 Gene Transfer.

The prominent role of dendritic cells (DC) in promoting tolerance and the development of methods to generate clinical grade products allowed the clinical application of tolerogenic DC (tolDC)-based therapies for controlling unwanted immune responses. We established an efficient method to generate tolerogenic human DC, producing supra-physiological levels of IL-10, by genetically engineering monocyte-derived DC with a bidirectional Lentiviral Vector (bdLV) encoding for IL-10 and a marker gene. DCIL−10 are mature DC, modulate T cell responses, promote T regulatory cells, and are phenotypically and functionally stable upon stimulation. Adoptive transfer of human DCIL−10 in a humanized mouse model dampens allogeneic T cell recall responses, while murine DCIL−10 delays acute graft-vs.-host disease in mice. Our report outlines an efficient method to transduce human myeloid cells with large-size LV and shows that stable over-expression of IL-10 generates an effective cell product for future clinical applications in the contest of allogeneic transplantation.

Dopamine transporter gene expression within the nucleus accumbens plays important role in the acquisition and reinstatement of ethanol-seeking behavior in mice

Alcoholism and alcohol use disorders are chronically relapsing conditions which is a major problem in treating alcohol addiction. In a previous study we showed that the dopamine transporter (DAT) is implicated in voluntary intake and preference. However, its role in modulating ethanol-associated contextual memory remains largely unknown. In this study we have investigated the role of DAT in ethanol-induced conditioned place preference (EtOH-CPP) acquisition and reinstatement in adult male C57BL/6 mice. For this purpose, we used both loss- and gain-of-function approaches to test the effects of central DAT manipulation on EtOH-CPP. We developed a lentiviral-mediated gene transfer approach to examine whether DAT knockdown (shDAT) or overexpression in the nucleus accumbens (Nacc) is enough to impair EtOH-CPP acquisition and reinstatement. In the first experiment, results showed that DAT knockdown blocked, whereas DAT overexpression, exacerbated the acquisition of EtOH-CPP. In the second experiment and after the EtOH-CPP expression, the mice were subjected to a 14-day extinction trials before drug-induced EtOH-CPP reinstatement was induced by a priming injection of 1 g/kg EtOH. Results indicated that reinstatement of EtOH-CPP was considerably decreased after accumbal shDAT injection. However, DAT overexpression significantly increased EtOH-CPP reinstatement. Finally, and following DAT mRNA quantification using RT-PCR, Pearson’s correlation showed a strong positive relationship between accumbal DAT mRNA and EtOH-CPP acquisition and reinstatement. These results suggest that DAT expression in the Nacc is involved in the acquisition and retrieval of EtOH contextual memory and that blockade of this transporter can decrease the rewarding properties of EtOH.

Genetically modified C3A cells with restored urea cycle for improved bioartificial liver

The bioartificial liver, a hybrid device aimed at improving the survival of patients with fulminant liver failure, requires a cell source to replicate human liver function. However, liver support systems that utilize porcine or human hepatoma-derived cells felt short of expectations in clinical trials. Here we present engineered C3A cells, with a restored function of the urea cycle, which can be used in an efficacious bioartificial liver. The genetic modification was performed using a lentiviral-mediated gene transfer which led to effective integration of the transgenes, coding for arginase I and ornithine transcarbamylase, into the target cell genomes. The engineered cells are more resistant to the oxidative/nitrosative stress induced by the presence of high concentrations of ammonia cations and produce more urea than their unmodified counterparts. Interestingly, the genetically modified cells secrete more albumin than control C3A cells and the synthesis of the protein is induced by increasing concentrations of ammonia. Although the physiological capabilities of the new cell line need to be further examined, at this stage of our study we may conclude that the genetically modified cells are able to convert ammonia to urea more effectively than regular C3A cells.

Production of Lentivirus for the Establishment of CAR-T Cells.

One of the most versatile gene transfer methods involves the use of recombinant lentiviral vectors since they can transduce both dividing and nondividing cells, are considered to be safe and provide long-term transgene expression since the integrated viral genome, the provirus, is passed on to daughter cells. These characteristics are highly desirable when a modified cell must continue to express the transgene even after multiple cell divisions. Lentiviral vectors are often used to introduce protein encoding cDNAs, such as reporter genes, or for noncoding sequences, such as mediators of RNA interference or genome editing, including shRNA or gRNA, respectively. In the gene therapy setting, lentiviral vectors have been used successfully for the modification of hematopoietic stem cells, resulting in restored immune function or correction of defects in hemoglobin, to name but a few examples. The success of chimeric antigen receptor (CAR) T cells for the treatment of B cell leukemias and lymphomas has been particularly striking and this approach has relied heavily on lentivirus-mediated gene transfer. Here we present a typical protocol for the production of lentivirus, concentration by ultracentrifugation and determination of virus titer. The resulting virus can then be used in laboratory assays of gene transfer, including the establishment of CAR T cells.

ALDH-Dependent Glycolytic Activation Mediates Stemness and Paclitaxel Resistance in Patient-Derived Spheroid Models of Uterine Endometrial Cancer.

SummaryUterine endometrial cancer is associated with poor survival outcomes in patients with advanced-stage disease. Here, we developed a three-dimensional cell cultivation method of endometrioid cancer stem-like cells with high aldehyde dehydrogenase (ALDH) activity from clinical specimens. ALDH inhibition synergized with paclitaxel to block cancer proliferation. In the clinical setting, high ALDH1A1 expression was associated with poor survival. A high level of ALDH correlated with an increase of glucose uptake, activation of the glycolytic pathway, and elevation of glucose transporter 1 (GLUT1). Blockade of GLUT1 inhibited characteristics of cancer stem cells. Similarly to ALDH inhibition, GLUT1 inhibition synergized with paclitaxel to block endometrial cancer proliferation. Our data indicated that ALDH-dependent GLUT1 activation and the resulting glycolytic activation are of clinical importance for both prognostic evaluation and therapeutic decision-making in endometrial cancer patients. In addition, the synergistic effects of taxane compounds and ALDH or GLUT1 inhibitors may serve as a new clinical treatment option for endometrial cancer.

Sox11-modified mesenchymal stem cells accelerate cartilage defect repair in SD rats.

Cartilage has a limited capacity to heal. Previously, we have shown that overexpression of Sox11 in rMSCs (Rat Mesenchymal Stem Cells) by lentivirus-mediated gene transfer leads to enhanced tri-lineage differentiation and accelerated bone formation in fracture model of rats. We observed that the fracture repair in the rats that received Sox11-modified rMSCs injection proceeded through an endochondral ossification process much faster than those in the control groups. However, the detailed role of Sox11 in rMSCs chondrogenic differentiation, as well as cartilage defect, is still not clearly clarified. Therefore, this study tests the hypothesis that Sox11 promotes chondrogenesis and cartilage defect repair by regulating β-catenin. Sox11 was transduced into rMSCs using lentiviruses. The expression levels of β-catenin and its downstream genes were evaluated by quantitative RT-PCR. The transcriptional activation of β-catenin was proved by dual-luciferase reporter assay and co-immunoprecipitation was performed to evaluate Sox11-β-catenin interaction. In addition, a cartilage defect model in SD rats was used to evaluate the cartilage regeneration ability of Sox11-modified rMSCs in vivo. We found that Sox11 transcriptionally activated β-catenin expression and discovered the core promoter region (from - 242 to - 1414) of β-catenin gene for Sox11 binding. In addition, Sox11 might regulate β-catenin at the post-transcriptional level by protein-protein interaction. Finally, using a cartilage defect model in rats, we found Sox11-modified rMSCs could improve cartilage regeneration. Taken together, our study shows that Sox11 is an important regulator of chondrogenesis and Sox11-modified rMSCs may have clinical implication for accelerating cartilage defect healing.

Advanced Methods for the Investigation of Cell Contact Dynamics in Endothelial Cells Using Florescence-Based Live Cell Imaging

Endothelial cells of the vascular system are dynamic cells whose molecular adaptability is decisive for the adjustment of homeostasis and organ perfusion. Advanced microscopic techniques, automation processing, and image analysis software was shown to improve the understanding of vascular biology. In this work, we describe advanced methods that allow investigating the dynamics of endothelial cell contacts. The development of viral vectors has contributed significantly to the genetic manipulation of endothelial cells. We used the Gibson assembly as a quick and cheap cloning system for introducing sequences into the lentiviral-based pFUGW vector. Furthermore, classical fluorescence tags such as mCherry and EGFP were compared with self-labeling tags such as Halo and SNAP for their suitability to study junction dynamics in cultured endothelium, and found the self-labeling tags as useful tools. Using such combinations, we found maintained cell junction integrity during shear stress-induced junction remodeling using VE-cadherin-EGFP. Remodeling was accompanied by VE-cadherin plaque formation, indicating that this process is mediated by the for­mation of the actin-driven junction-associated intermittent lamellipodia, JAIL. The combined methods including the Gibson assembly, lentiviral mediated gene transfer, spinning disk-based live cell imaging, and software for quantification allow analyses of the endothelial cell junction dynamics under static and under shear stress conditions.

The Improvement and Application of Lentivirus-Mediated Gene Transfer and Expression System in Penaeid Shrimp Cells.

This study first reported the improvement and application of lentivirus-mediated gene transfer and expression system in shrimp cells. After modified by the inclusion of two envelope proteins (VP19 and VP28) of shrimp white spot syndrome virus (WSSV) into the envelope of the packaged lentivirus, and insertion of a truncated promoter of immediate-early gene 1 (Pie1-504) of shrimp WSSV virus into the lentiviral reporter plasmid, the second-generation lentiviral expression system (pLVX-PEF1α-IRES-mCherry, psPAX2, and PMD2.G) was found to behave better in the mitosis-arrested shrimp cells than the similarly modified retrovirus expression system did. Results from the insect sf9 cells indicated that the inclusion of VP19 and VP28 into the envelope of packaged lentiviruses could significantly improve the tropism or infectivity of the modified lentiviruses to insect cells in a cumulative way. Notably, the VP28 contributed about 86% of the total increase of the tropism. In the shrimp primary lymphoid cells infected by modified lentivirus IV with both VP19 and VP28 included, the infection efficiency was up to 11% (non-confocal) and 19% (confocal) and no background fluorescent signal was observed. However, background fluorescent signal was observed in the shrimp primary Oka organ cells although only under a confocal microscope. In the lentivirus IV-infected Oka organ cells, the actual infection efficiencies were calculated up to 8% (non-confocal) and 19% (confocal), significantly higher than those of commercial intact lentivirus I of 0 (non-confocal) and 3% (confocal). The insertion of WSSV promoter (Pie1-504) had interrupted the effective expression of reporter plasmid encoding lentiviral construct of pLVX-PEF1α-Pie1-504-IRES-mCherry in the HEK293T cells, but markedly increased its efficiencies up to 14% (non-confocal) and 26% (confocal) in the Oka organ cells. This improved lentivirus expression system will provide us a useful tool for efficient gene transfer and expression in shrimp cells.

CAR-Modified Th1/Tc1-Polarized T-Rapa Cells Dissociate Inflammatory Cytokine Secretion from Anti-Tumor Cytotoxicity

▪Introduction: Despite some striking clinical success thus far, chimeric antigen receptor (CAR) engineered cells have the potential to cause severe side effects. Neurotoxicity and cytokine release syndrome (CRS), the latter characterized by increased levels of cytokines such as IL-6, IFN-γ, and MCP-1, are common adverse events associated with CAR therapy. Lymphodepleting preconditioning regimens are associated with improved clinical responses to CAR therapy, yet lymphodepletion has also been identified as a risk factor for CRS. Understanding and management of these toxicities has improved significantly, however these conditions are challenging to treat and can be life-threatening. The ability to limit or prevent initiation of CRS would greatly improve the safety of CAR therapy.Previous clinical trials have shown that T-Rapa cells (patient T cells that have been grown exvivo in rapamycin) can be successfully infused back into autologous recipients after a low-dose conditioning regimen. After infusion, these T-Rapa cells have potent effector functions and demonstrate long-term persistence. Here we determine that T-Rapa cells, engineered by lentivirus-mediated gene transfer to express an anti-CD19 CAR, are just as effective at killing tumor cells as similarly-engineered pan T cells but produce dramatically less IFN-γ, for example.Methods: Human CD3+ cells were treated with rapamycin in the presence of IFN-α and IL-2 to produce T-Rapa cells with a Th1/Tc1 phenotype. An anti-CD19-41BB-CD3ζ CAR construct was subcloned into a lentiviral vector backbone containing an IRES-eGFP element. Vector was prepared and used to transduce T or T-Rapa cells. Transgene expression was assessed by FACS for eGFP and Protein L staining for the CAR. CAR-T cells were then expanded using CD3/CD28 beads in the presence of IL-2. The expanded cells were used in assays including FACS assessment of T cell phenotype, co-culture assays, and 51Cr release assays in comparison with non-rapamycin treated CAR T cells and non-transduced controls.Results: Following transduction and expansion, similar eGFP and CAR expression levels were found in T and T-Rapa cells transduced at the same MOI. CAR-T and CAR-T-Rapa cells developed from multiple independent T cell donors exhibited similar phenotypes at days 5 and 14 post-thaw, as determined by analyses of T-cell subset and exhaustion markers including CD45RO, CD127, CCR7, CD95, CD25, CXCR3, CTLA-4, PD-1, LAG-3, and TIM-3. Both CAR-T and CAR-T-Rapa cells exhibited comparable levels of cytotoxicity against CD19+ Raji, SUP-B15 and RS4;11 cancer cell lines after coculture for 4 hours in a 51Cr release assay. Further, both T and T-Rapa CAR cells produced similar amounts of IL-2 following a 24-hour coculture with CD19+ Raji, SUP-B15 and RS4;11 cancer cell lines, as measured by ELISA. Interestingly, CAR-T-Rapa cells produced significantly less IFN- γ that CAR-T cells after 24 hours of coculture with CD19+ tumor cells. This observation was consistent for CAR-T and CAR-T-Rapa cells assessed at both day 5 and day 14 post-thaw.Conclusions: T-Rapa cells can be successfully transduced with a CAR vector, and show comparable T cell subset, exhaustion phenotype, and cytotoxicity to CAR-T cells that have not been treated with rapamycin. In spite of these similarities, when challenged with CD19+ tumor cells, CAR-T-Rapa cells produced less IFN-γ than CAR-T cells. Decreased production of IFN- γ may reduce the risk and severity of CRS, improving the safety of CAR therapy. Additional cytokine production studies, as well as in vivo studies, are underway to further characterize T-Rapa cells as a novel CAR effector cell type. DisclosuresFelizardo:Rapa Therapeutics: Employment, Patents & Royalties. Zhu:Rapa Therapeutics: Employment, Patents & Royalties. Fowler:Rapa Therapeutics: Employment, Equity Ownership, Patents & Royalties. Medin:Rapa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.