scholarly journals Ultrasound Combined with Microbubbles Mediated Factor VIII Plasmid Gene Therapy in Hemophilia a Mice

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2039-2039
Author(s):  
Shuxian Song ◽  
James Harrang ◽  
Bryn Smith ◽  
Carol H. Miao

Abstract Hemophilia A is a genetic bleeding disorder resulted from a deficiency of blood clotting factor VIII. In order to develop the efficient approach to gene therapy for hemophilia A, we previously explored reporter gene transfer mediated by ultrasound (US) combined with microbubbles (MBs). It was demonstrated that US/MB can significantly enhance gene transfer efficiency and serve as an efficient non-viral physical delivery strategy. In this study, we further delivered a therapeutic FVIII plasmid into the livers of hemophilia A (HA) mice. In consideration of FVIII synthesis from multiple tissues/cell lines, we first explored the distribution of gene expression using a pGL4.13 [luc2/SV40] luciferase plasmid driven by a ubiquitous promoter. One day following gene transfer, hepatocytes and endothelia cells were isolated from treated lobes by liver perfusion and centrifuge method. Evaluation of luciferase levels in two cell populations indicated that luciferase predominantly expressed in hepatocytes (5.35´104 RLU/107 cells vs. 1.46´103 RLU/107 cells in endothelia cells). Furthermore, gene transfer of pGFP (driven by a ubiquitous CMV promoter) mediated by US/MB also showed fluorescence distribution mostly in hepatocytes. These results indicate that hepatocyte is the predominant site of gene expression following US/MB mediated gene transfer into the liver. Based on these results, a hepatocyte-specific human FVIII plasmid (pBS-HCRHP-hFVIII/N6A) was used for US/MB mediated gene transfer in HA mice. In the short-term experiment, FVIII activity levels of treated HA mice ranged from 4-40% of normal FVIII activity. To follow FVIII expression for longer term, HA mice were pretreated with IL-2/IL-2 mAb (JES6-1) complexes on day −5, −4, and −3 to prevent immune response. In addition, the mice were infused with normal mouse plasma and human FVIII protein prior to gene transfer to maintain hemostasis. Subsequently, FVIII plasmids and 5 Vol% NUVOX MBs were injected into the mouse liver under simultaneous US exposure (1.1MHz transducer H158A driven by a pulse generator and high-power radio frequency amplifier capable of generating up to 1000W). Blood and liver samples were collected at serial time points after treatment to determine FVIII activity in plasma and liver damage. Following gene transfer, 10-30% of FVIII activity was achieved on day 4 and persisted in the average level of 20% by day 28. In a separate long-term follow-up experiment (n=3), 2 of 3 mice still maintained 10-30% activity after 120 days. Both transaminase levels (alanine aminotransferase and aspartate aminotransferase) and histological examination showed that the procedure of plasmid/MBs portal-vein injection and pulse-train acoustic exposure produced transiently localized liver damages however the damages were repaired and the liver recovered rapidly. Phenotypic correction of HA mice was further examined by tail clip assay. Blood loss of US/MB treated mice was significantly reduced compared with naive HA mice. Furthermore, a novel plasmid encoding a B domain-deleted FVIII variant containing mutations of 10 amino acids in the A1 domain (BDDFVIII-X10, a kind gift from Weidong Xiao) was constructed. Preliminary results from ongoing study showed that the gene transfer efficiency could be further improved with better plasmid and more efficient immune modulation. Together all the results indicate that US/MB mediated gene transfer is highly promising for efficient and safe gene therapy of hemophilia A. Disclosures No relevant conflicts of interest to declare.

2021 ◽  
Author(s):  
Michela Milani ◽  
Cesare Canepari ◽  
Tongyao Liu ◽  
Mauro Biffi ◽  
Fabio Russo ◽  
...  

Abstract Liver gene therapy with adeno-associated viral (AAV) vectors delivering a clotting factor transgene into hepatocytes has shown multi-year therapeutic benefit in adults with hemophilia. However, anti-AAV pre-existing immunity and the mostly episomal nature of AAV vectors, currently challenges application of AAV-vector mediated liver gene therapy to people with anti-AAV neutralizing antibodies and young pediatric patients. We have developed lentiviral vectors (LV), which integrate in the host cell genome, which achieve stable and efficient liver gene transfer in mice, dogs and non-human primates (NHP), by intravenous (i.v.) delivery. Here we show long-term coagulation factor VIII (FVIII) activity and restoration of hemostasis, by LV i.v. gene therapy to newborn and adult hemophilia A mice and normal-range FVIII activity in NHP, paving the way for potential clinical application.


Blood ◽  
2011 ◽  
Vol 117 (3) ◽  
pp. 798-807 ◽  
Author(s):  
Natalie J. Ward ◽  
Suzanne M. K. Buckley ◽  
Simon N. Waddington ◽  
Thierry VandenDriessche ◽  
Marinee K. L. Chuah ◽  
...  

Abstract Gene therapy for hemophilia A would be facilitated by development of smaller expression cassettes encoding factor VIII (FVIII), which demonstrate improved biosynthesis and/or enhanced biologic properties. B domain deleted (BDD) FVIII retains full procoagulant function and is expressed at higher levels than wild-type FVIII. However, a partial BDD FVIII, leaving an N-terminal 226 amino acid stretch (N6), increases in vitro secretion of FVIII tenfold compared with BDD-FVIII. In this study, we tested various BDD constructs in the context of either wild-type or codon-optimized cDNA sequences expressed under control of the strong, ubiquitous Spleen Focus Forming Virus promoter within a self-inactivating HIV-based lentiviral vector. Transduced 293T cells in vitro demonstrated detectable FVIII activity. Hemophilic mice treated with lentiviral vectors showed expression of FVIII activity and phenotypic correction sustained over 250 days. Importantly, codon-optimized constructs achieved an unprecedented 29- to 44-fold increase in expression, yielding more than 200% normal human FVIII levels. Addition of B domain sequences to BDD-FVIII did not significantly increase in vivo expression. These significant findings demonstrate that shorter FVIII constructs that can be more easily accommodated in viral vectors can result in increased therapeutic efficacy and may deliver effective gene therapy for hemophilia A.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5477-5477
Author(s):  
Kerry L. Titus ◽  
Paul Lee ◽  
H. Trent Spencer ◽  
Christopher Doering

Abstract A major obstacle for gene therapy of hemophilia A is the achievement of adequate factor VIII (fVIII) expression. Bioengineering strategies have targeted specific sequences within human fVIII that are thought to be responsible for its generally poor expression. Specific amino acid substitutions, L303E/F309S herein referred to as double mutation (DM), function to decrease fVIII binding to BiP, a resident ER chaperone, which results in increased fVIII secretion (Swaroop, Moussalli et al. 1997). Furthermore, addition of 6 N-linked glycosylation sites, designated 226/N6, located within the human B domain also increases human fVIII expression (Miao, Sirachainan et al. 2004). We previously demonstrated that porcine and certain hybrid human/porcine fVIII constructs are expressed at 10 – 14-fold greater levels than human fVIII (Doering, Healey et al. 2002; Doering, Healey et al. 2004). The aim of the current study was to directly compare various fVIII expression constructs in order to determine an optimal transgene for gene therapy applications. The following fVIII constructs were generated: human B-domain-deleted fVIII (HBDD-fVIII), HBDD-fVIII with a 14 amino acid linker between the A2 domain and the activation peptide (HSQ-fVIII), porcine fVIII containing a 24 amino acid linker (HEP-fVIII), hybrid human/porcine-fVIII which has porcine A1 and A3 domains (HP47), and modified HBDD, HSQ and HEP-fVIII constructs containing DM and/or 226/N6. Each construct was transiently transfected into BHK-M cells, and fVIII production between 48 – 72 hrs post-transfection was measured using a one-stage clotting assay. Under these conditions, the addition of the DM and 226/N6 significantly increased fVIII expression for HBDD (P = 0.003), though not for HSQ. Addition of DM or 226/N6 alone did not significantly increase the expression of either human fVIII construct, and furthermore, the addition of DM to HEP-fVIII decreased its expression 98%. HEP-fVIII was expressed at 8-fold or greater levels than any of the other human constructs. Next, ~25 stably transfected BHK-M clones were isolated following transfection with each of the fVIII expression constructs and the rate of fVIII production for each clone was determined. Several clones did not express detectable fVIII activity (<0.01 units/mL) and were excluded from the analysis. Approximately 14% of the total number of clones were excluded, ranging from 0 – 42% for the different constructs. HEP-DM-fVIII was the exception, where 82% of the clones had activity <0.01 units/mL. Mean HEP-fVIII expression was 3.93 ± 3.22 units/mL/24 hr (n = 19) (Figure 1), and HP47 was similarly expressed at 3.21 ± 2.31 units/mL/24 hr (n = 19). All of the HSQ-based constructs and HBDD-DM/226/N6 showed similar mean expression levels (0.28 ± 0.03 units/mL/24 hr) and were significantly higher than HBDD and HBDD-DM, which had a mean of 0.12 ± 0.01 units/mL. In the current study, we provide experimental evidence that the expression of HEP-fVIII and HP47 is superior to other bioengineered fVIII expression constructs, which should eliminate the expression barrier that has hampered the clinical translation of gene therapy for hemophilia A. Figure 1: Stable Transfectants Figure 1:. Stable Transfectants


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3238-3238
Author(s):  
Irene Zolotukhin ◽  
Brett Palaschak ◽  
David M Markusic ◽  
Roland Herzog

Abstract Hemophilia A is the X-linked bleeding disorder resulting from the loss of functional clotting factor VIII (FVIII). Hemophilia A patients with severe disease (<1% residual FVIII activity) experience spontaneous bleeds into the joints and closed spaces with severe morbidity. Restoration of hemostasis is managed by repeated infusions (2-3 times per week) of plasma derived or recombinant FVIII protein. While a standard treatment is available for patients, life-long infusions of FVIII protein is very expensive, has a negative impact on the patient's quality of life, and FVIII protein products are not available worldwide. Hence, there is a need to develop a more robust and cost effective treatment for hemophilia A patients. Liver-directed gene therapy using adeno-associated virus (AAV) represents a promising approach to treat hemophilia A. However, previous studies have shown that overexpression of human FVIII protein in the context of hydrodynamic delivery of plasmid vectors induces ER stress mediated through the unfolded protein response (UPR). Because human FVIII protein is inefficiently secreted into circulation, high AAV vector doses will be required to obtain therapeutic expression levels. Therefore, we sought to determine if AAV-FVIII gene delivery also triggers cellular UPR in hepatocytes in vivo. To this end, we selected to use a codon-optimized FVIII cDNA, which has been shown by our lab to significantly increase FVIII protein expression, and a high vector dose of AAV8-ApoE-hAAT-cohF8, containing a hepatocyte-specific enhancer/promoter combination. We evaluated this vector at doses of 1 x 1011 vg (4x1012 vg/kg) and 1 x 1012 vg (4x1013 vg/kg) in hemophilia A mice on a 129/BL6 background. Intravenous administration of the highest vector dose completely restored hemostasis, which was sustained and achieved super-physiological levels in some animals. Importantly, none of these mice developed inhibitors against FVIII. Next, we administered the vector at the same 2 doses to C67BL/6 mice, which show higher hepatic transduction efficiency than other strains. Experimental controls consisted of mice, with no vector or 1x1012 vg of AAV8-ApoE-hAAT-F9, expressing human factor IX (FIX) protein. Injection of tunicamycin, a potent inducer of the ER stress response, served as a positive control for all assays. Vector-treated mice were studied 2 and 4 weeks after gene transfer (n=3-4 per group). First, we evaluated the status of key molecular chaperones, known to be the mediators of the UPR: Bip, p-PERK, and p-eIF2a. Western blotting performed on the liver lysates indicated modest up-regulation of all three markers compared to normal control, but that effect was neither dose nor gene dependent. In addition, we tested the splicing of Xbp1 mRNA by PCR assay and observed low level of the 26 bp spliced fragment, indicative of the UPR, at the high vector dose. Immunohistochemistry on liver sections from each of our experimental groups including H&E staining, Tunnel staining for apoptotic cells, and reactive oxygen species staining. None of the stains yielded evidence for liver damage even in the 1x1012 AAV8-cohF8 treated mice compared to untreated controls. There was also no elevation of liver enzyme levels in plasma samples. Analysis of plasma from vector injected mice showed systemic levels of human FVIII and FIX proteins at ~30 ng/ml and ~6300 ng/ml, respectively (these ELISA-based measurements likely underestimate FVIII levels due to interference by von Willebrand factor). Overall our results suggest that over-expression of coagulation factors in hepatocytes from AAV vectors causes a mild cell stress response that is not strong enough to cause liver toxicity, is not specific for FVIII, and does impact expression or immunogenicity. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
1995 ◽  
Vol 85 (9) ◽  
pp. 2447-2454 ◽  
Author(s):  
RC Hoeben ◽  
FJ Fallaux ◽  
SJ Cramer ◽  
DJ van den Wollenberg ◽  
H van Ormondt ◽  
...  

Hemophilia A is caused by a deficiency of factor-VIII procoagulant (fVIII) activity. The current treatment by frequent infusions of plasma-derived fVIII concentrates is very effective but has the risk of transmittance of blood-borne viruses (human immunodeficiency virus [HIV], hepatitis viruses). Use of recombinant DNA-derived fVIII as well as gene therapy could make hemophilia treatment independent of blood-derived products. So far, the problematic production of the fVIII protein and the low titers of the fVIII retrovirus stocks have prevented preclinical trials of gene therapy for hemophilia A in large-animal models. We have initiated a study of the mechanisms that oppose efficient fVIII synthesis. We have established that fVIII cDNA contains sequences that dominantly inhibit its own expression from retroviral as well as from plasmid vectors. The inhibition is not caused by instability of the fVIII mRNA (t1/2, > or = 6 hours) but rather to repression at the level of transcription. A 305-bp fragment is identified that is involved in but not sufficient for repression. This fragment does not overlap the region recently identified by Lynch et al (Hum Gene Ther 4:259, 1993) as a dominant inhibitor of RNA accumulation. The repression is mediated by a cellular factor (or factors) and is independent of the orientation of the element in the transcription unit, giving the repressor element the hallmarks of a transcriptional silencer.


Diseases ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 57 ◽  
Author(s):  
Chiaki Hidai ◽  
Hisataka Kitano

Although the development of effective viral vectors put gene therapy on the road to commercialization, nonviral vectors show promise for practical use because of their relative safety and lower cost. A significant barrier to the use of nonviral vectors, however, is that they have not yet proven effective. This apparent lack of interest can be attributed to the problem of the low gene transfer efficiency associated with nonviral vectors. The efficiency of gene transfer via nonviral vectors has been reported to be 1/10th to 1/1000th that of viral vectors. Despite the fact that new gene transfer methods and nonviral vectors have been developed, no significant improvements in gene transfer efficiency have been achieved. Nevertheless, some notable progress has been made. In this review, we discuss studies that report good results using nonviral vectors in vivo in animal models, with a particular focus on studies aimed at in vivo gene therapy to treat cancer, as this disease has attracted the interest of researchers developing nonviral vectors. We describe the conditions in which nonviral vectors work more efficiently for gene therapy and discuss how the goals might differ for nonviral versus viral vector development and use.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3537-3537 ◽  
Author(s):  
Dominika Jirovska ◽  
Peiqing Ye ◽  
Steven W. Pipe ◽  
Carol H. Miao

Abstract Due to the large size of FVIII, a B-domain deleted FVIII (BDD-FVIII) cDNA is usually used for developing gene therapy protocols for treating hemophilia A. Inefficient transcription of wild- type FVIII cDNA can be overcome by deletion of the heavily glycosylated B-domain encoding portion of the gene. BDD-FVIII is as clinically efficacious and not more immunogenic than full-length recombinant FVIII. More recently, it was demonstrated that a partial deletion of the B-domain leaving an N-terminal 226 amino acid stretch containing 6 putative asparagine-linked glycosylation sites intact (FVIII/N6) was able to increase in vitro and in vivo secretion of FVIII by 10–15 fold. We have inserted this B domain variant FVIII/N6 cDNA into our liver-specific gene expression vector. The resulting construct, FVIII/N6 plasmid was delivered into the hemophilia A mouse liver by the hydrodynamic method. In control mice treated with BDD-FVIII plasmid (n=5/group), FVIII expression dropped to undetectable levels at 2 weeks post injection and high-titer anti-FVIII antibodies were generated in all the plasmid-treated mice. However, in mice treated with FVIII/N6 plasmid (n=5/group), one out of five mice never developed inhibitory antibodies and still had some FVIII gene expression (~10%) at 8 weeks post gene transfer. Three FVIII/N6 plasmid-treated mice developed anti-FVIII antibodies with significantly reduced inhibitor titer and only one mouse developed high-titer inhibitory antibodies. The CD4+ T cells isolated from the spleen of mice injected with FVIII/N6 constructs proliferated less in response to FVIII stimulation than those from mice injected with BDD-FVIII. These results indicate that FVIII/N6 protein is less immunogenic than BDD-FVIII. Interestingly, both BDD-FVIII and FVIII/N6 constructs produced similar levels of FVIII gene expression (100–300%) initially following nonviral gene transfer. However this could be due to saturation of the ER to Golgi transport apparatus for FVIII by the initial high-level gene expression. Gene expression levels produced by using reduced dosages of BDD-FVIII and FVIII/N6 plasmids are currently being evaluated and compared. These findings suggest that use of a FVIII/N6 construct decreases transgene-specific immune responses following nonviral gene transfer and facilitates long-term gene expression.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 29-29 ◽  
Author(s):  
Qizhen Shi ◽  
Erin L. Kuether ◽  
Brian C. Cooley ◽  
Scot A. Fahs ◽  
Jocelyn A. Schroeder ◽  
...  

Abstract Abstract 29 The development of inhibitory antibodies to exogenous factor VIII (FVIII) is considered a severe and important complication of FVIII infusion in hemophilia A patients. Gene therapy of hemophilia A with inhibitors is especially challenging because functional FVIII activity may be inactivated by circulating inhibitory antibodies if transgene protein is constitutively secreted into the blood circulation. Our previous studies have demonstrated that syngeneic transplantation of hematopoietic stem cells from 2bF8 transgenic mice that express platelet-specific FVIII can efficiently restore hemostasis to hemophilic mice with pre-existing inhibitory antibodies. In the current study, we assessed whether lentivirus-mediated 2bF8 gene transfer could efficiently introduce 2bF8 transgene expression and ameliorate the hemorrhagic phenotype in hemophilic mice with pre-existing immunity. To mimic the clinical situation of an autologous transplant in an inhibitor patient, both donor and recipient FVIIInull mice were immunized with recombinant human B-domain deleted FVIII to induce inhibitory antibody development. Platelet-derived FVIII expression in FVIIInull mice was introduced by 2bF8 lentiviral-mediated bone marrow (BM) transduction and syngeneic transplantation. Following BM reconstitution, mice were analyzed by PCR, quantitative real-time PCR, platelet lysate FVIII activity assay, and inhibitor assay. Phenotypic correction was assessed by tail clip survival test and electrolytic-induced thrombus formation. Expression of the 2bF8 product was detected in all recipients that received 2bF8 lentivirus transduced BM cells, indicating viable engraftment of BM genetically modified with the 2bF8 lentivirus transfer vector. Functional platelet-FVIII activity levels in the transduced mice with pre-existing immunity ranged from 0.36 to 6.18 mU/108 platelets (mean 1.56 ± 1.76 mU/108 platelets, n = 10), which was not significantly different from the levels obtained from a parallel non-inhibitor model (1.46 ± 0.87 mU/108 platelets, n = 4). Real-time PCR demonstrated that there was an average of 0.17 ± 0.05 LV DNA copies per cell in peripheral white blood cells from transduced mice. FVIII inhibiter titer gradually declined with the time, indicating that transduced platelet FVIII is well protected from exposure to the immune system, avoiding activation of a memory response. The tail clip survival test showed that 90% of mice survived tail clip challenge. The electrolytic injury model demonstrated that hemostasis was improved in recipients that received 2bF8 lentivirus-transduced BM cells. Furthermore, BM transferred from the primary transplant recipients into immunized FVIIInull secondary recipients demonstrated sustained platelet-FVIII expression, resulting in the correction of the hemophilia A phenotype with pre-existing immunity. This shows that gene transfer has occurred within long-term repopulating hematopoietic stem cells even in the presence of inhibitory antibodies. These results demonstrate that lentivirus-mediated bone marrow transduction/transplantation can provide sustained improvement of hemostasis in hemophilic mice with pre-existing immunity, indicating that this approach may be a promising strategy for gene therapy of hemophilia A with inhibitory antibodies in humans. Disclosures: Montgomery: GTI Diagnostics: Consultancy; Baxter: Consultancy; AstraZeneca: Consultancy; Bayer: Research Funding; CSL Behring: Membership on an entity's Board of Directors or advisory committees.


Sign in / Sign up

Export Citation Format

Share Document