Abstract
Statement of the Problem: Recombinant glycoprotein
expression has been carried out in different expression
systems based on the genetic modification. Specifically,
recombinant glycoproteins whose biological activity
depends on post-translational modifications are produced
in cell tissue culture, which increases the manufacturing
cost. The production of biotherapeutics in the mammary
glands of genetically modified mammals results in an
alternative method to overcome the drawback of cell
culture expression system. However, the N-glycosylation
pattern of complex glycoproteins produced in the
mammary epithelia has showed diminished antennae
formation and lower sialic acid contents compare to
native protein. An alternative to obtain high- quality
biopharmaceuticals in milk could be the modification of
the N-glycosylation pattern by overexpression of
exogenous glycosyltransferases. The purpose of this study
is to modify in vivo the glycosylation pattern of
recombinant protein expressed in goat mammary gland.
Methodology & Theoretical Orientation: Human
erythropoietin fused to human IgG Fc (EPO-Fc) was coexpressed with N-acetyl-glucosaminyltransferase-IVa
(GnT-IVa) by adenoviral transduction in goat mammary
gland. Findings: The modification in vivo of the
enzymatic glycosylation machinery in the mammary
gland generated an increment in the antennae number. A
higher population of tri-antennary structures for the EPOFc/GnT-IV variant was obtained by N-glycans mass
spectrometry analysis, compared to bi-antennary
structures N- linked to EPO-Fc expressed in the same
cells. Conclusion & Significance: These results
demonstrate, for the first time, that it is possible to modify
in vivo the glycosylation pattern of recombinant
biopharmaceutical expressed in the goat mammary gland
epithelial cells to obtain a glycosylation pattern similar to
native glycoproteins.
Keywords
Biochemistry, Glycoprotein
Biochemistry is both life science and a chemical science - it explores the chemistry of living organisms and the molecular basis for the changes occurring in living cells. It uses the methods of chemistry,
"Biochemistry has become the foundation for understanding all biological processes. It has provided explanations for the causes of many diseases in humans, animals and plants."
physics, molecular biology, and immunology to study the structure and behaviour of the complex molecules found in biological material and the ways these molecules interact to form cells, tissues, and whole organisms.
Biochemists are interested, for example, in mechanisms of brain function, cellular multiplication and differentiation, communication within and between cells and organs, and the chemical bases of inheritance and disease. The biochemist seeks to determine how specific molecules such as proteins, nucleic acids, lipids, vitamins, and hormones function in such processes. Particular emphasis is placed on the regulation of chemical reactions in living cells.
