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International Journal of Bioprinting dECM bioink for in vitro disease modeling

ECM composition exhibits tissue specificity. The dECM 2.2.1. Extracellular matrix in central nervous system
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provides a tissue-specific microenvironment containing The nervous system is a sophisticated network of neurons
various receptors and growth factors. Moreover, tissue- and glia cells. ECM is an important constituent of the
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specific dECMs directly transmit special chemical signals, network, accounting for 10–20% of the volume of the
such as cytokines and growth factors, to surrounding nervous system. For the central nervous system (CNS),
cells, inducing cell growth and tissue-specific cellular the main components are the basement membrane
responses. 38 and perineural nets, including the neural interstitial
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The differences in properties between the dECMs matrix. The basement membrane is a thin membrane
of different organs affect the spatial distribution of and an interface that separates astrocytic attachment
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cell surface receptors that regulate cell morphology and perivascular mesenchymal tissue. It provides a
and behavior. Furthermore, dECMs regulate organ- barrier, which is called the blood–brain barrier (BBB),
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specific cell proliferation, migration, and behavior by setting apart the neural tissues and the vascular structure
participating in tissue polarization and transmission of to protect the neural tissue from external pathogen.
mechanical forces, and serve as a structural support for In addition, the basement membrane is essential for
cells. Additionally, specific components of the dECM neural cell attachment and differentiation during the
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are involved in organ development and maturation. For developmental process. The basement membrane
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example, laminin promotes cell adhesion and migration, consists of laminin, nidogen, collagens, fibronectin,
and fibronectin is essential for heart, lung, and kidney and glycans, which are essential for the maintenance of
formation and maturation. 41,42 The tissue specificity of the barrier integrity. The perineuronal net is composed of
dECM can be applied to 3D-bioprinted organ mimicry various chondroitin sulfate proteoglycans (CSPGs), such
and development of disease models that recapitulate actual as neurocan, veriscan, brevican, and aggrecan, which
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pathophysiology. The pathological dysfunction in ECM primarily regulate neural plasticity of the perineuronal
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induces disorder in various tissues, such as brain, liver, nets. For example, CSPGs in the nets regulate excitatory
and lung. Here, we briefly review the ECM composition and inhibitory signal balance. Among these CSPGs,
in the tissues of central nervous system, cardiac tissues, brevicans interact with tenascin-R and regulate synaptic
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liver tissues, and tissues of respiratory system, as well as plasticity. Another feature of the CNS is the neural
the role of ECM proteins. The main tissue-specific ECM interstitial matrix, which is located between neurons and
compositions are summarized in Table 1. glial cells. 49

Table 1. Main composition and role of tissue-specific extracellular matrix
Tissue Main components of ECM Role of each ECM
Central nervous Laminin/Nidogen Basement membrane, neural cell attachment, regulation of neural differentiation
system Fibronectin Perineuronal nets, structural support, oligodendrocyte differentiation
Type IV collagen Perineuronal nets, structural support, neural cell migration support
CSPGs Perineuronal nets, regulation of signal balance between excitatory and inhibitory signals
Cardiac tissue Fibronectin Regulation of cardiac cellular polarity
Type IV collagen Mechanical support to cardiac cells
Proteoglycans Regulation of cardiac cellular differentiation
Liver Types I and III collagen Maintenance of structure
Fibrillin Regulation of elasticity and flexibility
Hyaluronic acid Filling gaps in tissue
Proteoglycans Regulation of gas exchange between cells
Respiratory system Types I, III, and IV collagen Maintenance of organelle formation
Glycosaminoglycans Responsible for gas exchange
Hyaluronic acid Filling gaps in tissue
Proteoglycans Formation of gel state in tissue
Elastin Providing elasticity and flexibility
Abbreviations: CSPGs, chondroitin sulfate proteoglycans; ECM, extracellular matrix.

Volume 10 Issue 2 (2024) 135 doi: 10.36922/ijb.1970