Study of matrix metalloproteinase-9 (mmp-9) nanoparticles and their potential to optimize the cow dry period

• Autores: Laia Gifre Renom
• Directores de la Tesis: Anna Aris Giralt (dir. tes.), Elena García i Fruitós (dir. tes.), David Reverter Cendrós (tut. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2019
• Idioma: español
• Materias:
  • Química
    • Bioquímica
      • Proteínas
  • Ciencias agrarias
    • Fitopatología
      • Bacterias
    • Ciencias veterinarias
      • Inmunología
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• Resumen

  • There is a worldwide action plan under the motto One Health, calling for the urgent minimization in the use of antibiotics at all levels –human, animal and environmental– in the joint battle against the antimicrobial resistance (AMR) crisis that threatens global health. The development of new preventive strategies to treat infection diseases has become, therefore, an essential initiative since the use of preventive antibiotics is being banned. In dairy cattle, the dry period is a sensitive phase in which cows easily suffer of intramammary infections, or mastitis, due to the temporally inefficient immune condition in the mammary gland. In this context, alternatives are required in order to control and reduce mastitis incidence at dry-off and to diminish the need of antibiotics. Inclusion bodies (IBs), which are protein aggregates recombinantly produced in bacteria and with an easy and low-cost scale-up, have already demonstrated a great potential in research areas such as tissue engineering and cancer therapy. With the aim of exploring their potential into the animal production sector, this thesis has been focused to cover all steps in the way along the development, characterization and application of this novel and promising protein-based therapy in dairy sector. Starting from the acquisition of soluble MMP-9 by solubilizing IBs using a newly described protocol for Generally Recognized as Safe (GRAS) bacteria protein-factories, we have been able to develop new MMP-9 delivery formats and to compare them with IB performances. The greater stability shown by IBs when compared with other formats brought us to consider their applicability in vivo. As a first step, their administration in a murine model revealed for the first time that their potential as an immunostimulant agent could be importantly dissected into two distinct effects. One effect, unspecific and ephemeral, was driven by the IB format whereas the other effect was MMP-9-specific and extended in time. These encouraged us to try to uncover what would be the effects triggered in their ultimate target, the bovine mammary gland at dry-off. Although MMP-9 had not a relevant specific role triggering the early stages of involution in this context, we observed that these protein aggregates accelerated from 3 to 6 days the onset of involution biomarkers, the release of natural bacteriostatic peptides such as lactoferrin, and the recruitment of immune cells in the mammary gland though an unspecific action. Therefore, these results consolidate MMP-9 IBs as a potent immunostimulatory –although unspecific– agent in the bovine mammary gland at dry-off, and reveal that new opportunities are yet to be explored in the use of protein nanoparticles to reach a more specific effect in the acceleration of the mammary gland involution and immune system.