41 research outputs found

    Functional factor VIII made with von Willebrand factor at high levels in transgenic milk

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    Background—Current manufacturing methods for recombinant human Factor VIII (rFVIII) within mammalian cell cultures are inefficient which limit the abundance needed for affordable, worldwide treatment of hemophilia A. However, rFVIII has been expressed at very high levels by the transgenic mammary gland of mice, rabbits, sheep and pigs. Unfortunately, it is secreted into milk with low specific activity due in part to the labile, heterodimeric structure that results from furin processing of its B domain. Objectives—To express biologically active rFVIII in the milk of transgenic mice through targeted bioengineering. Methods—Transgenic mice were made with a mammary specific FVIII gene (226/N6) bioengineered for efficient expression and stability containing a B domain with no furin cleavage sites. 226/N6 was expressed with and without von Willebrand Factor (VWF). 226/N6 was evaluated by ELISA, SDS-PAGE, Western blot, and one- and two-stage clotting assays. Hemostatic activity of immunoaffinity enriched 226/N6 was studied in vivo by infusion into hemophilia A knockout mice. Results and conclusions—With or without co-expression of VWF, 226/N6 was secreted into milk as a biologically active single chain molecule that retained high specific activity similar to therapeutic-grade FVIII. 226/N6 had \u3e450-fold higher IU/ml than previously reported in cell culture for rFVIII. 226/N6 exhibited similar binding to plasma-derived VWF as therapeutic-grade rFVIII and intravenous infusion of transgenic 226/N6 corrected the bleeding phenotype of hemophilia A mice. This provides proof-of-principle to study expression of 226/N6 and perhaps other single chain bioengineered rFVIII in the milk of transgenic livestock

    Bovine Follicular Dynamics, Oocyte Recovery,and Development of Oocytes Microinjected with a Green Fluorescent Protein Construct

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    The present study was carried out to 1) evaluate the viability of in vitro fertilized zygotes after microinjection of DNA, 2) assess the influence of oocyte quality upon the development rate of embryos when injected with DNA, and 3) determine the integration frequency of green fluorescent protein DNA into microinjected embryos. Oocytes were aspirated from ovaries of nine nonlactating Holsteins and were categorized into grades A, B, C, and D. At 16 h after in vitro fertilization, approximately half of the pronuclear stage presumptive zygotes were classified as having 1 pronucleus or 2 pronuclei, and they were microinjected with DNA constructs. A potential predictor of DNA integration frequency at d 10 was assessment of the incidence of green fluorescing embryos. The proportion of cleaved embryos that developed to morulae or blastocysts was not different between groups with 1 pronucleus injected (45%), 1 pronucleus uninjected (64%), or 2 pronuclei injected (49%). However, the development of morulae or blastocysts was higher in the group with 2 pronuclei uninjected (69%). The overall developmental score of green fluorescent protein-positive embryos was higher for grade A oocytes (1.3 &#;&#;0.1) than for grade B (0.8 &#; 0.1), C (0.6 &#;&#;0.1), or D (0.3 &#;&#;0.1) oocytes. The results show that production of transgenic bovine blastocysts can occur from the microinjection of a presumptive zygote having only one visible pronucleus. Initial oocyte quality is an important factor in selection of oocytes suitable for microinjection of DNA and for preimplantation development to produce bovine transgenic embryos

    Haemophilic factors produced by transgenic livestock: abundance that can enable alternative therapies worldwide

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    Haemophilia replacement factors, both plasma-derived and recombinant, are in relatively short supply and are high-cost products. This has stymied the study and development of alternative methods of administration of haemophilia therapy even in the most economically advanced countries, owing to the large amounts of material needed because bioabsorption and bioavailability of haemophilic factors can be less than 10% when using non-intravenous routes of delivery. There is therefore a need to increase access to therapy worldwide by decreasing the cost and increasing the abundance so that therapy can be achieved through simplified, alternative delivery methods. Transgenic livestock have been used to produce haemophilic factors in milk. Only the pig mammary gland has been shown to carry out the post-translational processing necessary to enable both the biological activity and long circulation half-life needed for therapeutic glycoproteins. Furthermore, the large amounts of recombinant protein that can be produced from pig milk make feasible the use of alternative delivery methods such as oral, intratracheal, subcutaneous, and intramuscular administration

    Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk

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    Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock

    Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk

    Get PDF
    Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock

    KiDS+GAMA:The weak lensing calibrated stellar-to-halo mass relation of central and satellite galaxies

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    We simultaneously present constraints on the stellar-to-halo mass relation for central and satellite galaxies through a weak lensing analysis of spectroscopically classified galaxies. Using overlapping data from the fourth data release of the Kilo-Degree Survey (KiDS), and the Galaxy And Mass Assembly survey (GAMA), we find that satellite galaxies are hosted by halo masses that are 0.53±0.390.53 \pm 0.39 dex (68\% confidence, 3σ3\sigma detection) smaller than those of central galaxies of the same stellar mass (for a stellar mass of log(M/M)=10.6\log(M_{\star}/M_{\odot}) = 10.6). This is consistent with galaxy formation models, whereby infalling satellite galaxies are preferentially stripped of their dark matter. We find consistent results with similar uncertainties when comparing constraints from a standard azimuthally averaged galaxy-galaxy lensing analysis and a two-dimensional likelihood analysis of the full shear field. As the latter approach is somewhat biased due to the lens incompleteness and as it does not provide any improvement to the precision when applied to actual data, we conclude that stacked tangential shear measurements are best-suited for studies of the galaxy-halo connection.Comment: 12 pages, 10 figures, accepted for publication in A&

    Galaxy bias from galaxy–galaxy lensing in the DES science verification data

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    We present a measurement of galaxy–galaxy lensing around a magnitude-limited (iAB < 22.5) sample of galaxies from the dark energy survey science verification (DES-SV) data. We split these lenses into three photometric-redshift bins from 0.2 to 0.8, and determine the product of the galaxy bias b and cross-correlation coefficient between the galaxy and dark matter overdensity fields r in each bin, using scales above 4 h−1 Mpc comoving, where we find the linear bias model to be valid given our current uncertainties. We compare our galaxy bias results from galaxy–galaxy lensing with those obtained from galaxy clustering and CMB lensing for the same sample of galaxies, and find our measurements to be in good agreement with those in Crocce et al., while, in the lowest redshift bin (z ∼ 0.3), they show some tension with the findings in Giannantonio et al. We measure b· r to be 0.87 ± 0.11, 1.12 ± 0.16 and 1.24 ± 0.23, respectively, for the three redshift bins of width Δz = 0.2 in the range 0.2 < z < 0.8, defined with the photometric-redshift algorithm BPZ. Using a different code to split the lens sample, TPZ, leads to changes in the measured biases at the 10–20 per cent level, but it does not alter the main conclusion of this work: when comparing with Crocce et al. we do not find strong evidence for a cross-correlation parameter significantly below one in this galaxy sample, except possibly at the lowest redshift bin (z ∼ 0.3), where we find r = 0.71 ± 0.11 when using TPZ, and 0.83 ± 0.12 with BPZ

    Effect of Culture Conditions, Donor Age, and Injection Site on In Vitro Development of DNA Microinjected Porcine Zygotes

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    A series of experiments evaluated development of porcine zygotes microinjected with DNA in three culture media and two incubation temperatures, from postpubertal and prepubertal donors, and between zygotes injected with DNA into the pronucleus and the cytoplasm. Zygotes recovered from 36 postpubertal gilts in Exp. 1 were injected and cultured in modified NCSU-23, modified NCSU-37, and CZB media at 37°C or 39°C for 7 d. In Exp. 2, zygotes were collected from postpubertal or prepubertal gilts, microinjected with DNA, and cultured in modified NCSU-23. In Exp. 3 superovulated prepubertal gilts had DNA injected into the cytoplasm or pronucleus of zygotes. Mean percentages developing to the expanded or hatched blastocyst stage in modified NCSU-23 (42.9) and modified NCSU-37 (40.1) did not differ, but development was greater than that for zygotes cultured in CZB (8.8; P \u3c .05). Development was greater at 39°C ( P \u3c .05) than at 37°C (36.5 vs 24.6%). Microinjection of DNA decreased development (P \u3c .05) from that of noninjected controls (18.1 vs 43.1%). Zygotes from postpubertal gilts had a higher percentage (6 8.0) of expanded and hatched blastocysts than zygotes from prepubertal donors (29.0; P \u3c .05). No development difference was found between DNA injection into the pronucleus (23.1%) or cytoplasm ( 17.4% 1, but development was less than for control embryos (64.9%; P \u3c .05). DNA microinjected porcine zygotes can be successfully cultured to the expanded blastocyst stage in modified NCSU-23 and modified NCSU-37 media at 39°C. Microinjection of DNA decreases survival of embryos from prepubertal donors more than it decreases survival of embryos from postpubertal donors
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