Employing epigenetics to augment the expression of therapeutic proteins in mammalian cells

2006 ◽  
Vol 24 (3) ◽  
pp. 137-142 ◽  
Author(s):  
Ted H.J. Kwaks ◽  
Arie P. Otte
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yanli Wang ◽  
Sihai Zhao ◽  
Liang Bai ◽  
Jianglin Fan ◽  
Enqi Liu

Transgenic animal bioreactors can produce therapeutic proteins with high value for pharmaceutical use. In this paper, we compared different systems capable of producing therapeutic proteins (bacteria, mammalian cells, transgenic plants, and transgenic animals) and found that transgenic animals were potentially ideal bioreactors for the synthesis of pharmaceutical protein complexes. Compared with other transgenic animal expression systems (egg white, blood, urine, seminal plasma, and silkworm cocoon), the mammary glands of transgenic animals have enormous potential. Compared with other mammalian species (pig, goat, sheep, and cow) that are currently being studied as bioreactors, rabbits offer many advantages: high fertility, easy generation of transgenic founders and offspring, insensitivity to prion diseases, relatively high milk production, and no transmission of severe diseases to humans. Noticeably, for a small- or medium-sized facility, the rabbit system is ideal to produce up to 50 kg of protein per year, considering both economical and hygienic aspects; rabbits are attractive candidates for the mammary-gland-specific expression of recombinant proteins. We also reviewed recombinant proteins that have been produced by targeted expression in the mammary glands of rabbits and discussed the limitations of transgenic animal bioreactors.


2018 ◽  
Author(s):  
Shahar Bracha ◽  
Karoliina Hassi ◽  
Paul D. Ross ◽  
Stuart Cobb ◽  
Lilach Sheiner ◽  
...  

Protein therapy has the potential to alleviate many neurological diseases; however, delivery mechanisms for the central nervous system (CNS) are limited, and intracellular delivery poses additional hurdles. To address these challenges, we harnessed the protist parasite Toxoplasma gondii, which can migrate into the CNS and secrete proteins into cells. Using a fusion protein approach, we engineered T. gondii to secrete therapeutic proteins for human neurological disorders. We tested two secretion systems, generated fusion proteins that localized to the secretory organelles of T. gondii and assessed their intracellular targeting in various mammalian cells including neurons. We show that T. gondii expressing GRA16 fused to the Rett syndrome protein MeCP2 deliver a fusion protein that mimics the endogenous MeCP2, binding heterochromatic DNA in neurons. This demonstrates the potential of T. gondii as a therapeutic protein vector, which could provide either transient or chronic, in situ synthesis and delivery of intracellular proteins to the CNS.


2015 ◽  
Vol 31 (2) ◽  
pp. 522-531 ◽  
Author(s):  
Jason Richardson ◽  
Bhavana Shah ◽  
Pavel V. Bondarenko ◽  
Prince Bhebe ◽  
Zhongqi Zhang ◽  
...  

Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.


Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.


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