BIOLOGY OF THE DYNAMIC CONNECTIVE TISSUE (MCTS) IN INVERTEBRATE MARINE MODELS:AN INTEGRATED APPROACH
Tesi di Dottorato
Data di Pubblicazione:
2013
Citazione:
BIOLOGY OF THE DYNAMIC CONNECTIVE TISSUE (MCTS) IN INVERTEBRATE MARINE MODELS:AN INTEGRATED APPROACH / S. Tricarico ; tutor: F. Bonasoro, M.D. Candia Carnevali ; coordinatore: M. Ferraguti. UNIVERSITA' DEGLI STUDI DI MILANO, 2013 Jan 24. 25. ciclo, Anno Accademico 2012. [10.13130/tricarico-serena_phd2013-01-24].
Abstract:
Animal tissues are an immense source of inspiration for humans which actually mimic
(biomimetic approach) and use them for novel material design and production. Connective tissue is
the most important animal structural material and it (or its components) is often used as source of
inspiration/model for different applications. Its main extracellular matrix (ECM) component is
collagen. Currently, industrially available collagen is mainly of bovine origin that, however, carries
a risk of transmission of serious diseases (bovine spongiform encephalopathy, BSE, and
transmissible spongiform encephalopathy, TSE). Therefore, alternative and safer sources of
collagen are required for regenerative medicine and one of the safer and recently exploited source
are aquatic organisms.
The marine invertebrates that I used in this project (echinoderms, in particular sea urchins)
possess peculiar and unique connective tissues, called Mutable Collagenous Tissues (MCTs), which
could actually represent an alternative source of collagen. Moreover, MCTs undergo extremely
rapid, drastic and reversible changes (completely independent from any muscular contribution) in
their passive mechanical properties such as stiffness, tensile strength and viscosity under nervous
control. Several evidences suggest that MCTs are probably one of the key elements of the striking
regenerative capacities found in echinoderms, since they directly help the regenerative process, exante
creating the conditions and ex-post providing optimal growth-promoting environment and
“dynamic” structures for tissue healing and regeneration. MCTs could therefore represent a
valuable source of inspiration for biomaterial design addressed to biomedical applications.
The main general aim of this work was to acquire the appropriate knowledge of the model
we want to get inspiration from (MCTs) and to understand how natural MCTs actually work. In
particular, the specific objective was to define the basic biology of natural MCTs, particularly the
key-components and their fundamental interactions; this will be achieved through morphological,
biochemical, biomolecular and biomechanical characterizations.
This thesis is part of the MIMESIS Project financed by CARIPLO Foundation (2009). The
very ultimate challenge of the project is to explore the possible development of a new class of
biomimetic materials inspired to echinoderm MCT to be used for scaffolds for tissue regeneration
and cell colture studies.
The first approach consisted in the investigation of the MCT structural key-components,
including fibrillar proteins, proteoglycans (PGs) and glycosaminoglycans (GAGs) in order to deeply
investigate how the natural tissue works. The transmission electron microscopy technique was used
to obtain micro-scale view to understand the micro-organization of the ECM components. With this
detailed investigation the current knowledge of the structural organization of MCT ECM was
expanded.
The biochemical analysis with SDS-PAGE and Western blot analysis on collagen and
PGs/GAGs showed how complex MCTs are. We found that the fibrillar collagen has strong
similarities with collagen type I and that all the PGs/GAGs families are represented in MCTs but
with differences in quality and quantity according to the tissues analysed or to the related
mechanical state.
Another major focus of this work was the biomolecular approach related to a presumptive
key effector protein, tensilin. This factor, previously found and characterised in other echinoderms
(holothurians), is considered as responsible for mutability phenomena. In our study, attention was
addressed to “tensilin” possible presence and function in two common sea urchin species,
Strongylocentrotus purpuratus and Pa
Tipologia IRIS:
Tesi di dottorato
Keywords:
echinoderm ; echinoid ; paracentrotus lividus ; strongylocentrotus purpuratus ; collagen ; tensilin ; proteoglycan ; glycosaminoglycan ; biomaterial ; cell culture ; peristomial membrane ; compass depressor ligament ; connective tissue
Elenco autori:
S. Tricarico
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