Lentiviral Transduction Research Articles

Targeted Therapy of CEA-CAR-NK Cells Against Colorectal Cancer Cells

Objective: Investigate the cytotoxic effect of CAR-NK cells targeting CEA on colorectal cancer cells with positive CEA expression. Methods: The mRNA and protein levels of CEA in different CRC cell lines were detected by qRT-PCR and Western blot analysis. Lentiviral transduction was used to construct CAR-NK cells and empty vector CON-NK cells targeting CEA. Fluorescence microscopy and WB were used to determine whether the cells successfully constructed and expressed CAR structures. The effector NK cells were co-cultured with target cells, and the levels of LDH, IFN-γ, and GM-CSF were detected. The killing rate of effector cells was calculated, and the release of cytokines during the killing of target cells by different effector cells was compared. Results: The expression level of CEA in colorectal cancer patients was significantly higher than that in normal samples and other tumor samples, and the prognosis survival time of patients with high CEA expression was lower than that of CRC patients with low or no CEA expression (P < 0.05). The CEA expression of the HT29 cell line was significantly higher than that of the SW1116 cell line at both the mRNA and protein levels. CEA-CAR-NK92 cells and CON-NK92 cells expressed green fluorescence under a microscope, and WB results showed that CEA-CAR-NK92 cells successfully expressed the CAR structure. Compared with CON-NK92 cells and NK92 cells, CEA-CAR-NK92 cells effectively killed HT29 cells (P < 0.05). CEA-CAR-NK92 cells secreted a large amount of IFN-γ and GM-CSF during the killing of HT29 cells, while the cytokine secretion of CON-NK92 cells and NK92 cells was not significant (P < 0.05). Conclusion: CAR-NK92 cells targeting CEA can effectively kill CEA-positive colorectal cancer cells.

Knockdown of swine leukocyte antigen expression in porcine lung transplants enables graft survival without immunosuppression.

Immune rejection remains the major obstacle to long-term survival of allogeneic lung transplants. The expression of major histocompatibility complex molecules and minor histocompatibility antigens triggers allogeneic immune responses that can lead to allograft rejection. Transplant outcomes therefore depend on long-term immunosuppression, which is associated with severe side effects. To address this problem, we investigated the effect of genetically engineered transplants with permanently down-regulated swine leukocyte antigen (SLA) expression to prevent rejection in a porcine allogeneic lung transplantation (LTx) model. Minipig donor lungs with unmodified SLA expression (control group, n = 7) or with modified SLA expression (treatment group, n = 7) were used to evaluate the effects of SLA knockdown on allograft survival and on the nature and strength of immune responses after terminating an initial 4-week period of immunosuppression after LTx. Genetic engineering to down-regulate SLA expression was achieved during ex vivo lung perfusion by lentiviral transduction of short hairpin RNAs targeting mRNAs encoding β2-microglobulin and class II transactivator. Whereas all grafts in the control group were rejected within 3 months, five of seven animals in the treatment group maintained graft survival without immunosuppression during the 2-year monitoring period. Compared with controls, SLA-silenced lung recipients had lower donor-specific antibodies and proinflammatory cytokine concentrations in the serum. Together, these data demonstrate a survival benefit of SLA-down-regulated lung transplants in the absence of immunosuppression.

The involvement of krüppel-like transcription factor 2 in megakaryocytic differentiation induction by phorbol 12-myrestrat 13-acetate

BackgroundMegakaryocytic differentiation is a complicated process regulated by a series of transcription factors in a context- and stage-dependent manner. Recent studies have suggested that krüppel-like transcription factor 2 (KLF2) is involved in the control of embryonic erythroid precursor cell differentiation and maturation. However, the function and mechanism of KLF2 in regulating megakaryocytic differentiation remain unclear.MethodsThe expression patterns of krüppel-like transcription factors (KLFs) during megakaryocytic differentiation were identified from public databases. Phorbol 12-myristate 13-acetate (PMA) treatment of the myeloid-erythroid-leukemic cell lines K562 and HEL were used as cellular megakaryocytic differentiation models. A lentiviral transduction system was utilized to achieve the goal of amplifying or reducing KLF2. The expression of KLF2 was examined using real-time PCR and western blot. The impact of KLF2 on the megakaryocytic differentiation of K562 cells was examined by flow cytometry, Giemsa staining, Phalloidin staining and western blot. RNA-sequencing (RNA-seq) and chromatin immunoprecipitation-sequencing (ChIP-seq) technologies were used to identify the KLF2-regulated targets.ResultsKLF2 is increased in the maturation process of megakaryocytes. KLF2 overexpression accelerated the PMA-induced megakaryocytic differentiation, as reflected by an increased percentage of CD41/CD61 cells, an increased number of polyploid cells, and an elevated expression of P21 and P27. KLF2 knockdown exhibited the opposite results, indicating that KLF2 knockdown suppressed the megakaryocytic differentiation. Further, combination of the RNA-seq and ChIP-seq results suggested that chimerin 1 (CHN1) and potassium voltage-gated channel subfamily Q member 5 (KCNQ5) may be target genes regulated of KLF2. Both CHN1 and KCNQ5 knockdown could block the megakaryocytic differentiation to some content.ConclusionThis study implicated a regulatory role of KLF2 in megakaryocytic differentiation, which may suggest KLF2 as a target for illness with abnormal megakaryocytic differentiation.

Endometrial senescence is mediated by interleukin 17 receptor B signaling

BackgroundWe previously identified Il17RB, a member of the IL17 superfamily, as a candidate marker gene for endometrial aging. While IL17RB has been linked to inflammation and malignancies in several organ systems, its function in the endometrium has not been investigated and is thus poorly understood. In the present study, we performed a functional analysis of this receptor with the aim of determining the effects of its age-associated overexpression on the uterine environment.MethodsWe analyzed IL17RB-related signaling pathways and downstream gene expression in an immortalized human endometrial glandular epithelial cell line (“hEM”) forced to express the receptor via lentiviral transduction (“IL17RB-hEM”). We also prepared endometrial organoids from human endometrial tissue sourced from hysterectomy patients (“patient-derived EOs”) and exposed them to cytokines that are upregulated by IL17RB expression to investigate changes in organoid-forming capacity and senescence markers. We analyzed RNA-seq data (GEO accession number GSE132886) from our previous study to identify the signaling pathways associated with altered IL17RB expression. We also analyzed the effects of the JNK pathway on organoid-forming capacity.ResultsStimulation with interleukin 17B enhanced the NF-κB pathway in IL17RB-hEM, resulting in significantly elevated expression of the genes encoding the senescence associated secretory phenotype (SASP) factors IL6, IL8, and IL1β. Of these cytokines, IL1β inhibited endometrial organoid growth. Bioinformatics analysis showed that the JNK signaling pathway was associated with age-related variation in IL17RB expression. When IL17RB-positive cells were cultured in the presence of IL17B, their organoid-forming capacity was slightly but non-significantly lower than in unexposed IL17RB-positive cells, but when IL17B was paired with a JNK inhibitor (SP600125), it was restored to control levels. Further, IL1β exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1β was paired with SP600125, both indicators were restored to levels comparable to the control condition.ConclusionsWe have revealed an association between IL17RB, whose expression increases in the endometrial glandular epithelium with advancing age, and cellular senescence. Using human endometrial organoids as in vitro model, we found that IL1β inhibits cell proliferation and leads to endometrial senescence via the JNK pathway.

Scalable intracellular delivery via microfluidic vortex shedding enhances the function of chimeric antigen receptor T-cells.

Adoptive chimeric antigen receptor T-cell (CAR-T) therapy is transformative and approved for hematologic malignancies. It is also being developed for the treatment of solid tumors, autoimmune disorders, heart disease, and aging. Despite unprecedented clinical outcomes, CAR-T and other engineered cell therapies face a variety of manufacturing and safety challenges. Traditional methods, such as lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7- to 2-fold higher CAR-T yields compared to electroporation with superior cell viability and recovery. Hydroporated cells exhibited rapid proliferation, robust target cell lysis, and increased pro-inflammatory and regulatory cytokine secretion in addition to improved CAR-T yield by day 5 post-transfection. We demonstrate that scaled-up hydroporation can process 5 x 108 cells in less than 10 s, showcasing the platform as a viable solution for high-yield CAR-T manufacturing with the potential for improved therapeutic outcomes.

Umbilical cord blood T cells can be isolated and enriched by CD62L selection for use in 'off the shelf' chimeric antigen receptor T-cell therapies to widen transplant options.

Umbilical cord blood (UCB) T cells exhibit distinct naive ontogenetic profiles and may be an attractive source of starting cells for the production of chimeric antigen receptor (CAR) T cells. Pre-selection of UCB-T cells on the basis of CD62L expression was investigated as part of a machine-based manufacturing process, incorporating lentiviral transduction, CRISPR-Cas9 editing, T-cell expansion and depletion of residual TCReeeT cells. This provided stringent mitigation against the risk of graft versus host disease (GVHD), and was combined with simultaneous knockout of CD52 to enable persistence of edited T cells in combination with preparative lymphodepletion using Alemtuzumab. Under compliant manufacturing conditions, two cell banks were generated with high levels of CAR19 expression and minimal carriage of TCReeeT cells. Sufficient cells were cryopreserved in dose-banded aliquots at the end of each campaign to treat dozens of potential recipients. Molecular characterisation captured vector integration sites and CRISPR editing signatures and functional studies, including in vivo potency studies in humanised mice, confirmed antileukaemic activity comparable to peripheral blood-derived universal CAR19 T cells. Machine manufactured UCB derived T cells banks offer an alternative to autologous cell therapies and could help widen access to CAR T cells.

Design of iPSC-based cell model to study the functions of the <i>UBE2A</i> gene

BACKGROUND: The UBE2A protein belongs to the E2 family of ubiquitin-binding enzymes involved in the ubiquitination of substrate proteins. UBE2A mutations lead to congenital X-linked mental retardation syndrome-type Nascimento. How UBE2A participates in the central nervous system development is still unknown. AIM: To establish a cell model based on induced pluripotent stem cells (iPSCs) to study the molecular and cellular functions of UBE2A in neurogenesis. METHODS: Using genomic CRISPR-Cas9 editing and lentiviral transduction, a cell model based on iPSCs from two healthy donors was designed. This cell model includes isogenic iPSCs with knockout and inducible hyperexpression of UBE2A. In addition, iPSCs were obtained by reprogramming peripheral blood mononuclear cells of a patient diagnosed with X-linked mental retardation of Nascimento type, which has a deletion spanning the whole UBE2A locus. RESULTS: The obtained iPSCs demonstrate an ESC-like morphology. They express pluripotent cell markers OCT4, SOX2, SSEA-4, and TRA-1-81 and have normal karyotypes. iPSCs with UBE2A knockout or hyperexpression had significantly increased nuclei size compared with the isogenic control. CONCLUSION: The developed iPSC-based cell model can be used for fundamental studies of the functions of UBE2A in neurogenesis.

Utilizing epigenetic regulators to improve HSC-based lentiviral gene therapy

AbstractThe curative benefits of autologous and allogeneic transplantation of hematopoietic stem cells (HSCs) have been proven in various diseases. However, the low number of true HSCs that can be collected from patients and the subsequent in vitro maintenance and expansion of true HSCs for genetic correction remains challenging. Addressing this issue, we here focused on optimizing culture conditions to improve ex vivo expansion of true HSCs for gene therapy purposes. In particular, we explored the use of epigenetic regulators to enhance the effectiveness of HSC-based lentiviral (LV) gene therapy. The histone deacetylase inhibitor quisinostat and bromodomain inhibitor CPI203 each promoted ex vivo expansion of functional HSCs, as validated by xenotransplantation assays and single-cell RNA sequencing analysis. We confirmed the stealth effect of LV transduction on the loss of HSC numbers in commonly used culture protocols, whereas the addition of quisinostat or CPI203 improved the expansion of HSCs in transduction protocols. Notably, we demonstrated that the addition of quisinostat improved the LV transduction efficiency of HSCs and early progenitors. Our suggested culture conditions highlight the potential therapeutic effects of epigenetic regulators in HSC biology and their clinical applications to advance HSC-based gene correction.

Functional characterization of PI3K C2 domain mutations detected in breast cancer circulating tumor cells and metastatic cells

BackgroundIn breast cancer, over one third of all patients harbor a somatic mutation in the PIK3CA gene, encoding the p110α catalytic subunit of the phosphatidylinositol 3-kinase (PI3K) in their tumor cells. Circulating tumor cells (CTCs) are cells shed from the primary tumor into the blood stream. Recently, the long-term stable breast cancer CTC-ITB-01 cell line with tumorigenic and metastatic capacity was established from liquid biopsy derived cells. The oncogenic hotspot PIK3CA mutation H1047R (kinase domain) was detected in the primary tumor, CTCs and metastasis of the same patient. Other PIK3CA mutations located within the C2 domain (E418K and E453K) were detected in the CTCs and the vaginal metastasis but not in the primary tumor. The goal of our study was to functionally characterize the impact of the rare E418K and E453K mutations within the C2 domain that were not detected in the primary tumor. MethodsPIK3CA mutations E418K, E453K, H1047R were generated by site-directed mutagenesis and stably overexpressed in breast cancer cells by lentiviral transduction. Subsequent signaling pathway activation was examined by western blot analysis. The impact of PIK3CA mutations on biological processes was studied by live cell imaging using the Incucyte Zoom system. Structural modeling was conducted in Pymol. The membrane localization of the mutants was evaluated by separating the cytosolic and membrane fraction using ultracentrifugation. Drug susceptibility of CTC-ITB-01 cells was analyzed by live cell imaging. ResultsWestern blot analysis of human MDA-MB-231, MCF-7 and T47D breast cancer cells stably overexpressing either the PIK3CA wildtype (WT) or one of the E418K, E453K or H1047R mutants revealed a significant increase in AKT phosphorylation in both C2 mutants (E418K and E453K) and the kinase domain mutant H1047R. Functional analysis showed a significantly increased proliferation of MDA-MB-231 cells overexpressing the E453K and H1047R mutants. Migration was increased in all cells overexpressing WT and each of the mutants. Interestingly, invasion and chemotaxis were only enhanced in the MDA-MB-231 cells overexpressing the C2 domain mutants, i.e. E418K and E453K. In addition, membrane localization of the two C2 domain mutants was increased. Structural modeling of the E453K mutation suggests a disruption of the interaction between the negative regulatory domain of the p85α subunit and the p110α catalytic subunit as a potential mechanism leading to the observed activation of PI3K/AKT/mTOR signaling. Dual targeting of AKT/mTOR pathway by MK2206 and RAD001 leads to very strong synergistic effects (IC50 MK2206: 148 nM, IC50 RAD001: 15 nM) with respect to proliferation in the CTC-ITB-01 line through apoptosis induction. ConclusionsOur results demonstrate that PIK3CA C2 domain mutations activate PI3K downstream AKT signaling and can increase proliferation, migration and invasion after stable lentiviral transduction. Although both investigated mutations - E418K and E453K - are located within the C2 domain, a different molecular mechanism can be proposed. The PIK3CA mutated CTC-ITB-01 shows a high susceptibility against dual inhibition of AKT/mTOR. Further studies are required to fully elucidate the oncogenic potential of rare PIK3CA mutations.

Proteomic insights into the regulatory function of ARID1A in colon cancer cells.

The AT-rich interacting domain-containing protein 1A (ARID1A) is a tumor suppressor gene that has been implicated in several cancers, including colorectal cancer (CRC). The present study used a proteomic approach to elucidate the molecular mechanisms of ARID1A in CRC carcinogenesis. Stable ARID1A-overexpressing SW48 colon cancer cells were established using lentivirus transduction and the successful overexpression of ARID1A was confirmed by western blotting. Label-free quantitative proteomic analysis using liquid chromatography-tandem mass spectrometry identified 705 differentially altered proteins in the ARID1A-overexpressing cells, with 310 proteins significantly increased and 395 significantly decreased compared with empty vector control cells. Gene Ontology enrichment analysis highlighted the involvement of the altered proteins mainly in the Wnt signaling pathway. Western blotting supported these findings, as a decreased protein expression of Wnt target genes, including c-Myc, transcription factor T cell factor-1/7 and cyclin D1, were observed in ARID1A-overexpressing cells. Among the altered proteins involved in the Wnt signaling pathway, the interaction network analysis revealed that ARID1A exhibited a direct interaction with E3 ubiquitin-protein ligase zinc and ring finger 3 (ZNRF3), a negative regulator of the Wnt signaling pathway. Further analyses using the The Cancer Genome Atlas colon adenocarcinoma public dataset revealed that ZNRF3 expression significantly impacted the overall survival of patients with CRC and was positively correlated with ARID1A expression. Finally, an increased level of ZNRF3 in ARID1A-overexpressing cells was confirmed by western blotting. In conclusion, the findings of the present study suggest that ARID1A negatively regulates the Wnt signaling pathway through ZNRF3, which may contribute to CRC carcinogenesis.

Salidroside improves cognitive function in Parkinson’s disease via Braf-mediated mitogen‑activated protein kinase signaling pathway

ObjectiveTo delve into the underlying mechanism of Salidroside (Sal) on the improvement of cognitive function in Parkinson’s Disease (PD). MethodsThe experimental mice were divided into Control group, Model group [injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)], and Model+Sal (low concentration, high concentration) group. Mouse hippocampal tissues were extracted for RNA sequencing to obtain the core pathway and core gene. Mouse plasma was prepared and analyzed by LC-MS to obtain differential metabolites. In vitro experiments were verified by immunofluorescence and lentiviral transduction. ResultsELISA signaled that Sal facilitated the reduction of neuronal damage and inflammatory reaction in mice. MPTP_Sal_Low and MPTP_Sal_High groups had high levels of glial cell derived neurotrophie factor (GDNF) expression. Differentially expressed genes (DEGs) in control group, MPTP group and MPTP_Sal_High group were identified by transcriptomic, which were classified to the mitogen-activated protein kinase (MAPK) signaling pathway, and the core gene Braf was obtained. Metabolomics manifested that the differential metabolites involved DL-tyrosine, adenosine, phosphoenolpyruvate, and L-tryptophan. In vitro experiments verified that Sal treatment inhibited the up-regulation of p-p38, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal-regulated kinase (ERK) expression, and growth of neuronal protrusions. The OE-Braf group showed a significant up-regulation of the GDNF expression, a decrease in the expression of p-p38, p-JNK, and p-ERK, and a significant growth of neuronal protrusions. ConclusionSal may exert its effects in PD through the Braf-mediated MAPK signaling pathway, which can increase GDNF expression and promote neuronal protrusion growth for the protection of neurological function and the improvement of cognitive function.

IMMU-22. B7-H3 NANOBODY CAR-T AND SOLUBLE TREM2 GENETICALLY ENGINEERED MYELOID CELL THERAPY IN MURINE SYNGENEIC GLIOBLASTOMA

Abstract BACKGROUND Myeloid immunosuppression can be a major impediment to CAR-T cell therapy for CNS tumors. Importantly, CAR-T cells are often evaluated in immunocompromised mice which cannot accurately recapitulate the tumor immune response or tumor microenvironment. CNS tumor macrophages express TREM2, an important driver of immunosuppression. This study combines B7-H3 targeting nanobody CAR-T cells which are cross reactive in humans and mice (currently being evaluated for clinical development) with genetically engineered myeloid cells (GEMys) expressing soluble TREM2 (sTREM2) in a syngeneic mouse model of glioblastoma (GBM), with the aim of blocking TREM2-mediated immunosuppression to enhance CAR-T cell function. METHODS Syngeneic murine GBM, designed to mimic human GBM and generated at the Center for Advanced Preclinical Research (CAPR), was used for all studies. B7-H3 nanobody CAR-T cells were generated from mouse splenic T cells. In vitro tumor killing assays were performed by xCELLigence. sTREM2 GEMys were generated from bone marrow progenitor cells using lentiviral transduction. For in vivo studies, mice underwent orthotopic implantation of tumors and placement of an MRI-compatible, permanent catheter-port system for serial intracerebroventricular (ICV) administration of cell therapies. Mice were treated with CAR-T and/or GEMy therapies, evaluated weekly for tumor burden by MRI, and were monitored for survival. RESULTS Syngeneic GBM expression of B7-H3 was confirmed by flow cytometry, immunofluorescence, and western blot. B7-H3 nanobody CAR-T cells demonstrated effective killing of GBM by xCELLigence. sTREM2 GEMys were successfully generated and confirmed to produce sTREM2. Cell therapies were successfully infused ICV via the implanted catheter-port system, demonstrating safety and feasibility of this model for serial ICV cellular therapy. CONCLUSIONS B7-H3 nanobody CAR-T cells were validated against syngeneic GBM, and we have demonstrated safety and feasibility of ICV catheter administration of cellular therapies in vivo. Future studies will continue to evaluate in vivo timing and efficacy of CAR-T and GEMy therapy.

EPEN-21. EXPLORATION OF TUMOR SUPPRESSOR LATS1 LOSS IN POSTERIOR FOSSA GROUP A EPENDYMOMA WITH LOSS OF CHROMOSOME 6Q

Abstract INTRODUCTION Chromosome 6q loss (6q-) has recently been identified as an ultra-high-risk factor in posterior fossa group A ependymoma (PFA). This study seeks to pinpoint the biological mechanism underlying the aggressive biology of PFA 6q-. We hypothesize that loss of chromosome 6q gene large tumor suppressor kinase 1 (LATS1) in PFA 6q- results in increased Hippo pathway activity that drives malignant tumor progression. LATS1 is a key negative regulator of the Hippo pathway which may represent a novel therapeutic vulnerability in 6q- PFA. METHODS We are testing this hypothesis using genomic and transcriptomic analysis of PFA patient samples, and by gene knock-in and pharmaceutical interventions of LATS1 and Hippo pathway components in PFA 6q- models. RESULTS Tumor suppressor LATS1 shows reduced expression in PFA 6q- patient samples. Although complete loss of the entire 6q arm is common in PFA 6q-, partial loss of chromosome 6q is also observed, and in all cases this partial loss encompasses the LATS1 locus on chromosome 6q. We used lentiviral transduction to knock-in LATS1 in PFA 6q- cell lines to determine the effect on tumor growth. This demonstrated loss of viability that was specific for 6q- PFA cell lines versus 6q WT control cell lines. DISCUSSION Data point to LATS1 loss being a key driver of the aggressive phenotype of PFA6q-, implicating the Hippo pathway in PFA 6q- and potential for novel therapeutic strategies.

Spermatogonial stem cells in the 129 inbred strain exhibit unique requirements for self-renewal.

Spermatogonial stem cells (SSCs) undergo self-renewal division to sustain spermatogenesis. Although it is possible to derive SSC cultures in most mouse strains, SSCs from a 129 background never proliferate under the same culture conditions, suggesting they have distinct self-renewal requirements. Here, we established long-term culture conditions for SSCs from mice of the 129 background (129 mice). An analysis of 129 testes showed significant reduction of GDNF and CXCL12, whereas FGF2, INHBA and INHBB were higher than in testes of C57BL/6 mice. An analysis of undifferentiated spermatogonia in 129 mice showed higher expression of Chrna4, which encodes an acetylcholine (Ach) receptor component. By supplementing medium with INHBA and Ach, SSC cultures were derived from 129 mice. Following lentivirus transduction for marking donor cells, transplanted cells re-initiated spermatogenesis in infertile mouse testes and produced transgenic offspring. These results suggest that the requirements of SSC self-renewal in mice are diverse, which has important implications for understanding self-renewal mechanisms in various animal species.

Transcription Factor-Mediated Generation of Dopaminergic Neurons from Human iPSCs-A Comparison of Methods.

Dopaminergic neurons are the predominant brain cells affected in Parkinson's disease. With the limited availability of live human brain dopaminergic neurons to study pathological mechanisms of Parkinson's disease, dopaminergic neurons have been generated from human-skin-cell-derived induced pluripotent stem cells. Originally, induced pluripotent stem-cell-derived dopaminergic neurons were generated using small molecules. These neurons took more than two months to mature. However, the transcription-factor-mediated differentiation of induced pluripotent stem cells has revealed quicker and cheaper methods to generate dopaminergic neurons. In this study, we compared and contrasted three protocols to generate induced pluripotent stem-cell-derived dopaminergic neurons using transcription-factor-mediated directed differentiation. We deviated from the established protocols using lentivirus transduction to stably integrate different transcription factors into the AAVS1 safe harbour locus of induced pluripotent stem cells. We used different media compositions to generate more than 90% of neurons in the culture, out of which more than 85% of the neurons were dopaminergic neurons within three weeks. Therefore, from our comparative study, we reveal that a combination of transcription factors along with small molecule treatment may be required to generate a pure population of human dopaminergic neurons.

Surface-modified injectable poly(ethylene-glycol) diacrylate-based cryogels for localized gene delivery

Lentiviral transduction is widely used in research, has shown promise in clinical trials involving gene therapy and has been approved for CAR-T cell immunotherapy. However, most modifications are done ex vivo and rely on systemic administration of large numbers of transduced cells for clinical applications. A novel approach utilizing in situ biomaterial-based gene delivery can reduce off-target side effects while enhancing effectiveness of the manipulation process. In this study, poly(ethylene glycol) diacrylate (PEGDA)-based scaffolds were developed to enable in situ lentivirus-mediated transduction. Compared to other widely popular biomaterials, PEGDA stands out due to its robustness and cost-effectiveness. These scaffolds, prepared via cryogelation, are capable of flowing through surgical needles in both in vitro and in vivo conditions, and promptly regain their original shape. Modification with poly(L-lysine) (PLL) enables lentivirus immobilization while interconnected macroporous structure allows cell infiltration into these matrices, thereby facilitating cell-virus interaction over a large surface area for efficient transduction. Notably, these preformed injectable scaffolds demonstrate hemocompatibility, cell viability and minimally inflammatory response as shown by our in vitro and in vivo studies involving histology and immunophenotyping of infiltrating cells. This study marks the first instance of using preformed injectable scaffolds for delivery of lentivectors, which offers a non-invasive and localized approach for delivery of factors enabling in situ lentiviral transduction suitable for both tissue engineering and immunotherapeutic applications.

Trophoblast-specific overexpression of the LAT1 increases transplacental transport of essential amino acids and fetal growth in mice.

Placental System L amino acid transporter activity is decreased in pregnancies complicated by intrauterine growth restriction (IUGR) and increased in fetal overgrowth. However, it is unknown if changes in the expression/activity of placental Large Neutral Amino Acid Transporter Small Subunit 1 (Slc7a5/LAT1) are mechanistically linked to placental function and fetal growth. We hypothesized that trophoblast-specific Slc7a5 overexpression increases placental transport of essential amino acids, activates the placental mechanistic target of rapamycin (mTOR) signaling, and promotes fetal growth in mice. Using lentiviral transduction of blastocysts with a Slc7a5 transgene, we achieved trophoblast-specific overexpression of Slc7a5 (Slc7a5 OX) with increased fetal (+27%) and placental weights (+10%). Trophoblast-specific Slc7a5 overexpression increased trophoblast plasma membrane (TPM) LAT1 protein abundance and TPM System L transporter (+53%) and System A transporter activity (+ 21%). Slc7a5 overexpression also increased transplacental transport of leucine (+ 85%) but not of the System A tracer, 14C-methylamino isobutyric acid, in vivo. Trophoblast-specific overexpression of Slc7a5 activated placental mTORC1, as assessed by increased (+44%) phosphorylation of S6 ribosomal protein (Ser 235/236), and mTORC2 as indicated by phosphorylation of PKCα-Tyr-657 (+47%) and Akt-Ser 473 (+96%). This is the first demonstration that placental transport of essential amino acids is mechanistically linked to fetal growth. The decreased placental System L activity in human IUGR and the increased placental activity of this transporter in some cases of fetal overgrowth may directly contribute to the development of these pregnancy complications.

Establishment of human post-vaccination SARS-CoV-2 standard reference sera

There is a critical need to understand the effectiveness of serum elicited by different SARS-CoV-2 vaccines against SARS-CoV-2 variants. We describe the generation of reference reagents comprised of post-vaccination sera from recipients of different primary vaccines with or without different vaccine booster regimens in order to allow standardized characterization of SARS-CoV-2 neutralization in vitro. We prepared and pooled serum obtained from donors who received a either primary vaccine series alone, or a vaccination strategy that included primary and boosted immunization using available SARS-CoV-2 mRNA vaccines (BNT162b2, Pfizer and mRNA-1273, Moderna), replication-incompetent adenovirus type 26 vaccine (Ad26.COV2·S, Johnson and Johnson), or recombinant baculovirus-expressed spike protein in a nanoparticle vaccine plus Matrix-M adjuvant (NVX-CoV2373, Novavax). No subjects had a history of clinical SARS-CoV-2 infection, and sera were screened with confirmation that there were no nucleocapsid antibodies detected to suggest natural infection. Twice frozen sera were aliquoted, and serum antibodies were characterized for SARS-CoV-2 spike protein binding (estimated WHO antibody binding units/ml), spike protein competition for ACE-2 binding, and SARS-CoV-2 spike protein pseudotyped lentivirus transduction. These reagents are available for distribution to the research community (BEI Resources), and should allow the direct comparison of antibody neutralization results between different laboratories. Further, these sera are an important tool to evaluate the functional neutralization activity of vaccine-induced antibodies against emerging SARS-CoV-2 variants of concern. ImportanceThe explosion of COVID-19 demonstrated how novel coronaviruses can rapidly spread and evolve following introduction into human hosts. The extent of vaccine- and infection-induced protection against infection and disease severity is reduced over time due to the fall in concentration, and due to emerging variants that have altered antibody binding regions on the viral envelope spike protein. Here, we pooled sera obtained from individuals who were immunized with different SARS-CoV-2 vaccines and who did not have clinical or serologic evidence of prior infection. The sera pools were characterized for direct spike protein binding, blockade of virus-receptor binding, and neutralization of spike protein pseudotyped lentiviruses. These sera pools were aliquoted and are available to allow inter-laboratory comparison of results and to provide a tool to determine the effectiveness of prior vaccines in recognizing and neutralizing emerging variants of concern.

Poor in vivo transduction of myocardium by lentiviral vectors is likely caused by a post-entry block of transduction

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Stichting LSH-TKI Introduction In cardiac gene therapy, two prototypic viral vectors are typically considered for long-term transgene expression, i.e. lentivirus (LV) and adeno-associated virus (AAV) vectors. Compared to AAV vectors, LV vectors have the advantages of a larger insert capacity and the ability to confer permanent transgene expression due to integration of the vector genome in the host cell’s chromosomal DNA . However, standard VSV G protein-pseudotyped LV vectors (VSV G-LV vectors) has shown suboptimal transduction of cardiac myocytes in vivo. Purpose In this study, we aimed to improve LV-mediated transduction of cardiomyocytes in vivo by evaluating LV vectors carrying various different envelopes and compared the most potent variants with AAV1 capsid-pseudotyped AAV2 vectors (AAV2/1 vectors). Methods We made a panel of LV vectors pseudotyped with envelope proteins from 76 different viruses carrying an expression cassette for enhanced green fluorescent protein (eGFP). Transduction efficiencies in neonatal rat ventricular myocytes (NRVMs), human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and cardiomyocyte progenitor cells (CMPCs) were determined by fluorescence-activated cell sorting (FACS) as percentage eGFP-positive cells. Male NOD -SCID mice aged 3-6 months were injected directly into the left ventricular myocardium with eGFP-encoding VSV G-LV and AAV2/1 vectors at doses of 1.4 x 10^7 infectious units and 2.0 x 10^10 genome copies, respectively, or PBS as a control. Mice were sacrificed one and four weeks after surgery. Per heart, left ventricular and eGFP-positive area was determined from 40 – 50 slides and the ratio was used as a measure of transduction efficiency. Results Of the panel of pseudotyped LVs none was able to consistently outperform VSV G-LV vectors, which reached transduction efficiencies in vitro of 58% in NRVMs to 96% in hiPSC-CMs and 100% in CMPCs . In AAV2/1 vector-injected hearts, the eGFP expressing area in the left ventricle increased from 1.07% in week 1 to 5.42% in week 4. In contrast, eGFP expression in LV-injected hearts was 0.31% and 0.16% after 1 week and 4 weeks, respectively (figure 1). Conclusion In vitro screening of a panel of pseudotyped LV vectors showed standard VSV G-LV vectors as top performer. Despite encouraging in vitro results and previously reported findings, VSV G-LV vectors was unable to provide for robust in vivo transduction. The observation that none of the 76 different envelopes yielded a meaningful improvement of lentiviral transduction rates together with the discrepancy between in vitro and in vivo transduction efficiencies, suggest that a post-entry block of transduction likely represents an important component of the poor in vivo performance.Figure 1in vivo transduction

Genetically-modified, redirected T cells target hepatitis B surface antigen-positive hepatocytes and hepatocellular carcinoma lesions in a clinical setting.

Hepatitis B virus (HBV)-DNA integration in HBV-related hepatocellular carcinoma (HBV-HCC) can be targeted by HBV-specific T cells. SCG101 is an autologous, HBV-specific T-cell product expressing a T-cell receptor (TCR) after lentiviral transduction recognizing the envelope-derived peptide (S20-28) on HLA-A2. We here validated its safety and efficacy preclinically and applied it to an HBV-related HCC patient (NCT05339321). Good Manufacturing Practice-grade manufactured cells were assessed for off-target reactivity and functionality against hepatoma cells. Subsequently, a patient with advanced HBV-HCC (Child-Pugh class A, Barcelona Clinic Liver Cancer stage B, Eastern Cooperative Oncology Group performance status 0, hepatitis B e antigen-, serum hepatitis B surface antigen [HBsAg]+, HBsAg+ hepatocytes 10%) received 7.9×107 cells/kg after lymphodepletion. Safety, T-cell persistence, and antiviral and antitumor efficacy were evaluated. SCG101, produced at high numbers in a closed-bag system, showed HBV-specific functionality against HBV-HCC cells in vitro and in vivo. Clinically, treatment was well tolerated, and all adverse events, including transient hepatic damage, were reversible. On day 3, ALT levels increased to 1,404 U/L, and concurrently, serum HBsAg started decreasing by 3.84 log10 and remained <1 IU/mL for over six months. HBsAg-expressing hepatocytes in liver biopsies were undetectable after 73 days. The patient achieved a partial response according to modified RECIST with a >70% reduction in target lesion size. Transferred T cells expanded, developed a stem cell-like memory phenotype, and were still detectable after six months in the patient's blood. SCG101 T-cell therapy showed encouraging efficacy and safety in preclinical models and in a patient with primary HBV-HCC and concomitant chronic hepatitis B with the capability to eliminate HBsAg+ cells and achieve sustained tumor control after single dosing.