Transplantation of cord blood stem cells for treating hematologic diseases and strategies to improve engraftment

Pluripotent possibilities: human umbilical cord blood cell treatment after neonatal brain injury

Perinatal hypoxic-ischemic brain injury and stroke in the developing brain remain important causes of chronic neurologic morbidity. Emerging data suggest that transplantation of umbilical cord blood-derived stem cells may have therapeutic potential for neuroregeneration and improved functional outcome. The pluripotent capacity of stem cells from the human umbilical cord blood provides simultaneous targeting of multiple neuropathologic events initiated by a hypoxic-ischemic insult. Their high regenerative potential and naïve immunologic phenotype makes them a preferable choice for transplantation. A multiplicity of transplantation protocols have been studied with a variety of brain injury models; however, only a few have been conducted on immature animals. Biological recipient characteristics, such as age and sex, appear to differentially modulate responses of the animals to the transplanted cord blood stem cells. Survival, migration, and function of the transplanted cells have also been studied and reveal insights into the mechanisms of cord blood stem cell effects. Data from preclinical studies have informed current clinical safety trials of human cord blood in neonates, and further work is needed to continue progress in this field.

Cell lines expressing mutant FX proteins to generate proteins with reduced rate of fucosylation: WO2010/141478

BACKGROUND

The application (WO 2010/141478) is in the field of glycobiology and deals with the synthesis of recombinant proteins with a reduced rate of fucosylation.

OBJECTIVE

It aims at generating mammalian cell lines that express mutant forms of GDP-4-keto-deoxy-mannose-3,5,-epimerase-4-reductase (FX) and cells that conditionally fucosylate proteins.

METHODS

Mutant forms of FX were synthesized, and mammalian cell lines genetically engineered to express mutant FX proteins and the protein of interest. Cell lines that conditionally fucosylate proteins were generated from a mutant FX form that has reduced ability to fucosylate glycoproteins at 37°C and not at 34°C.

RESULTS

Cells genetically engineered to express mutant forms of FX protein show reduced ability to fucosylate proteins, particularly antibodies, with rates as low as 5 - 0.5% fucosylation, compared to cells expressing wild-type FX.

CONCLUSION

Cells genetically engineered to express the mutant forms of FX protein provide a means to synthesize and express proteins with a reduced rate of fucosylation. The paradigm may be used to synthesize antibodies that mediate antibody-dependent cell-mediated cytotoxicity more efficiently. The application uses mammalian cell lines, genetically engineered to express mutant FX proteins, to synthesize and produce proteins with a reduced rate of fucosylation. The application claims the conditional control of protein fucosylation by FX mutant proteins.

Modulation of GDP-fucose level for generating proteins with reduced rate of fucosylation (WO2010141855)

BACKGROUND

The application (WO2010141855) is in the field of glycobiology, and involves the control of the rate of fucosylation of proteins by exogenous factors.

OBJECTIVE

It aims at controlling the rate of protein fucosylation with inhibitors (drugs or nucleic acid antagonists) of enzymes involved in the synthesis of GDP-fucose.

METHODS

Mammalian cell lines were cultured in the presence of inhibitors, for example, siRNA. The rates of GDP-fucose in cells and during protein fucosylation were characterized.

RESULTS

The level of protein fucosylation decreases rapidly in response to a decrease in GDP-fucose level.

CONCLUSION

The relationship between the rate of fucosylation of proteins and the level of GDP-fucose in a cell is non-linear. Reduction in the rate of protein fucosylation can be achieved with a minimal reduction of the level of GDP-fucose in cells. The paradigm may be used to synthesize proteins and antibodies, with a reduced rate of fucosylation. The application claims that the use of drugs or nucleic acid antagonists that inhibit the enzymes involved in GDP-fucose biosynthesis optimizes the level of GDP-fucose present in cells, and reduces the rate of fucosylation of glycoproteins.

Chimeric proteins comprising the constant region of immunoglobulins for treating hemophilia B (WO2005001025)

The application (WO2005001025) details recombinant fusion proteins attached to the constant region of heavy chains of immunoglobulins. They are found to be particularly useful for the treatment of hemostatic disorders, such as hemophilia B. It aims at engineering chimeric proteins comprising of a single molecule of human factor IX (FIX) and the constant region (Fc domain) of one or two heavy chain(s) of human IgG (rFIXFc). cDNA for rFIXFc was generated by a PCR. rFIXFc protein was isolated and purified from stably transfected mammalian cells. The concentration and clotting activity of rFIXFc were assessed in mice, rats, monkeys, and FIX-deficient mice and dogs, after intravenous administration. The half-life of rFIXFc activity is prolonged by three to fourfold, compared with rFIX, when administered intravenously in all animals. The generation of chimeric proteins, comprised of FIX fused to the Fc domain of IgG, extends the clotting activity of the recombinant molecule. rFIXFc represents a promising candidate for the treatment of patients with hemophilia B. The application claims the methods of making recombinant chimeric proteins comprising of one biologically active molecule fused to the Fc region of the heavy chain(s) of immunoglobulins and their use for therapy.