Vasculature Growth - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 617

Table 10.7. Peptides released from cleavage of matrix constituents and chemotaxis (Source:

[ 1185 ]).

Peptidic fragments Effect

Collagen Neutrophil recruitment

Elastin Monocyte recruitment

Laminin Cell migration

Table 10.8. Peptides released from cleavage of matrix constituents and production of peptidases
and cytokines (Source: [ 1185 ]; MMP: matrix metallopeptidase; PAI: plasminogen activator
inhibitor; uPA: urokinase-type plasminogen activator [urokinase]).

Peptidic fragments Effect

Collagen Production of peptidases and cytokines

Elastin Production of peptidases and cytokines

Fibronectin Production of MMP9/12, cytokines

Hyaluronan Production of MMP12, PAI1, cytokines

Laminin-111 Production of MMP9, uPA

Laminin-511 Production of MMP9/14, cytokines

as well as (2) the interstitial matrix that surrounds the vasculature, such as collagen-
18, 18 collagen-8, 19 and collagen-15. 20
Both thrombospondin-1 and -2 as well as their proteolytically derived fragments
hinder angiogenesis during wound healing. Thrombospondin fragments are more
effective than full-length thrombospondins.
In addition, peptidic fragments that are cleavage products of collagen-1 and -4,
elastin, fibronectin, laminins, nidogens, thrombospondins, and hyaluronan operate
as chemotactic substances for inflammatory cells (Table 10.7 ).
These fragments can also induce specific gene expression programs in leuko-
cytes, in particular those of peptidases and cytokines (Table 10.8 ). In particular,
fragments of fibronectin and laminin increase the production of various peptidases
such as mt1MMP in monocytes and macrophages [ 1185 ].
Secreted protein acidic and rich in cysteine (SPARC) 21 isamemberofthe
group of non-structural components of the extracellular matrix. This secreted Ca 2 + -
binding glycoprotein modulates cell adhesion and proliferation, as it intervenes in
interactions between cells and their environment [ 1187 ]. 22 It is highly expressed in

18 A.k.a. endostatin and neostatin.
19 A.k.a. vastatin.
20 A.k.a. restin.
21 A.k.a. basement-membrane protein BM40 and osteonectin.
22 The Sparc gene is generally detected in cells with high rates of matrix production and prolifera-
tion. It can be identified in osteoblasts, odontoblasts, and chondrocytes, as well as megacaryocytes,
steroid-producing cells of adrenal glands and gonads, and cells of kidney glomeruli, bronchi, skin,
and large vessels [ 1188 ].