Publications (121) View all
-
Article: Topographically targeted osteogenesis of mesenchymal stem cells stimulated by inclusion bodies attached to polycaprolactone surfaces.
[show abstract] [hide abstract]
ABSTRACT: Aim: Bacterial inclusion bodies (IBs) are nanostructured (submicron), pseudospherical proteinaceous particles produced in recombinant bacteria resulting from ordered protein aggregation. Being mechanically stable, several physicochemical and biological properties of IBs can be tuned by appropriate selection of the producer strain and of culture conditions. It has been previously shown that IBs favor cell adhesion and surface colonization by mammalian cell lines upon decoration on materials surfaces, but how these biomaterials could influence the behavior of mesenchymal stem cells remains to be explored. Materials & methods: Here, the authors vary topography, stiffness and wettability using the IBs to decorate polycaprolactone surfaces on which mesenchymal stem cells are cultured. Results: The authors show that these topographies can be used to specifically target osteogenesis from mesenchymal stem cells, and through metabolomics, they show that the cells have increased energy demand during this bone-related differentiation. Conclusion: IBs as topographies can be used not only to direct cell proliferation but also to target differentiation of mesenchymal stem cells. Original submitted 12 October 2012; Revised submitted 22 January 2013.Nanomedicine 04/2013; · 5.05 Impact Factor -
Article: A nanostructured bacterial bioscaffold for the sustained bottom-up delivery of protein drugs.
[show abstract] [hide abstract]
ABSTRACT: Aims: Bacterial inclusion bodies (IBs) are protein-based, amyloidal nanomaterials that mechanically stimulate mammalian cell proliferation upon surface decoration. However, their biological performance as potentially functional scaffolds in mammalian cell culture still needs to be explored. Materials & methods: Using fluorescent proteins, we demonstrate significant membrane penetration of surface-attached IBs and a corresponding intracellular bioavailability of the protein material. Results: When IBs are formed by protein drugs, such as the intracellular acting human chaperone Hsp70 or the extracellular/intracellular acting human FGF-2, IB components intervene on top-growing cells, namely by rescuing them from chemically induced apoptosis or by stimulating cell division under serum starvation, respectively. Protein release from IBs seems to mechanistically mimic the sustained secretion of protein hormones from amyloid-like secretory granules in higher organisms. Conclusions: We propose bacterial IBs as biomimetic nanostructured scaffolds (bioscaffolds) suitable for tissue engineering that, while acting as adhesive materials, partially disintegrate for the slow release of their biologically active building blocks. The bottom-up delivery of protein drugs mediated by bioscaffolds offers a highly promising platform for emerging applications in regenerative medicine. Original submitted 25 June 2012; Revised submitted 18 September 2012.Nanomedicine 02/2013; · 5.05 Impact Factor -
Article: Overexpression of the nuclear factor kappaB inhibitor A20 is neurotoxic after an excitotoxic injury to the immature rat brain.
[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: The zinc finger protein A20 is an ubiquitinating/deubiquitinating enzyme essential for the termination of inflammatory reactions through the inhibition of nuclear factor kappaB (NF-kappaB) signaling. Moreover, it also shows anti-apoptotic activities in some cell types and proapoptotic/pronecrotic effects in others. Although it is known that the regulation of inflammatory and cell death processes are critical in proper brain functioning and that A20 mRNA is expressed in the CNS, its role in the brain under physiological and pathological conditions is still unknown. METHODS: In the present study, we have evaluated the effects of A20 overexpression in mixed cortical cultures in basal conditions: the in vivo pattern of endogenous A20 expression in the control and N-methyl-D-aspartate (NMDA) excitotoxically damaged postnatal day 9 immature rat brain, and the post-injury effects of A20 overexpression in the same lesion model. RESULTS: Our results show that overexpression of A20 in mixed cortical cultures induced significant neuronal death by decreasing neuronal cell counts by 45±9%. In vivo analysis of endogenous A20 expression showed widespread expression in gray matter, mainly in neuronal cells. However, after NMDA-induced excitotoxicity, neuronal A20 was downregulated in the neurodegenerating cortex and striatum at 10-24 hours post-lesion, and it was re-expressed at longer survival times in reactive astrocytes located mainly in the lesion border. When A20 was overexpressed in vivo 2 hours after the excitotoxic damage, the lesion volume at 3 days post-lesion showed a significant increase (20.8±7.0%). No A20-induced changes were observed in the astroglial response to injury. CONCLUSIONS: A20 is found in neuronal cells in normal conditions and is also expressed in astrocytes after brain damage, and its overexpression is neurotoxic for cortical neurons in basal mixed neuron-glia culture conditions and exacerbates postnatal brain excitotoxic damage.Neurological Research 12/2012; · 1.52 Impact Factor -
Article: Systems metabolic engineering, industrial biotechnology and microbial cell factories.
[show abstract] [hide abstract]
ABSTRACT: Cell factories have been largely exploited for the controlled production of substances of interest for food, pharma and biotech industries. Although human-controlled microbial production and transformation are much older, the cell factory concept was fully established in the 80's through the intensive public and private investment. Strongly empowered by the then nascent recombinant DNA technologies and supported by the approval of recombinant insulin, the principle of controlled biological production as a convenient source of difficult-to-obtain molecules (especially those of high added value) deeply penetrated the industrial tissue, soon becoming a widespread platform aiming at cost-effective large-scale production.Microbial Cell Factories 12/2012; 11(1):156. · 3.55 Impact Factor -
Article: Supramolecular organization of protein-releasing functional amyloids solved in bacterial inclusion bodies.
[show abstract] [hide abstract]
ABSTRACT: Slow protein release from amyloidal materials is a molecular platform used by nature to control protein hormone secretion in the endocrine system. The molecular mechanics of the sustained protein release from amyloids remains essentially unexplored. Inclusion bodies (IBs) are natural amyloids that occur as discrete protein nanoparticles in recombinant bacteria. These protein clusters have been recently explored as protein-based functional biomaterials with diverse biomedical applications, and adapted as Nanopills to deliver recombinant protein drugs into mammalian cells. Interestingly, the slow protein release from IBs does not significantly affect the particulate organization and morphology of the material, suggesting the occurrence of a tight scaffold. We have here determined, by using a combined set of analytical approaches, a sponge-like supramolecular organization of IBs combining differently folded protein versions (amyloid and native-like), which supports both mechanical stability and sustained protein delivery. Apart from offering structural clues about how amyloid materials release their monomeric protein components, these findings open exciting possibilities for the tailored development of smart biofunctional materials, adapted to mimic the functions of amyloid-based secretory glands of higher organisms.Acta biomaterialia 12/2012; · 3.98 Impact Factor
