Fast determination of three-dimensional fibril orientation of type-I collagen via macroscopic chirality

2017 ◽  
Vol 110 (2) ◽  
pp. 023702 ◽  
1981 ◽  
Vol 1 (10) ◽  
pp. 801-810 ◽  
Author(s):  
Karl A. Piez ◽  
Benes L. Trus

A specific fibril model is presented consisting of bundles of five-stranded microfibrils, which are usually disordered (except axially) but under lateral compression become ordered. The features are as follows (where D = 234 residues or 67 nm): (1) D-staggered collagen molecules 4.5 D long in the helical microfibril have a left-handed supercoil with a pitch of 400–700 residues, but microfibrils need not have helical symmetry. (2) Straight-tilted 0.5-D overlap regions on a near-hexagonal lattice contribute the discrete x-ray diffraction reflections arising from lateral order, while the gap regions remain disordered. (3) The overlap regions are equivalent, but are crystallographically distinguished by systematic displacements from the near-hexagonal lattice. (4) The unit cell is the same as in a recently proposed three-dimensional crystal model, and calculated intensities in the equatorial region of the x-ray diffraction pattern agree with observed values.


2009 ◽  
Vol 185 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Farideh Sabeh ◽  
Ryoko Shimizu-Hirota ◽  
Stephen J. Weiss

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.


1994 ◽  
Vol 3 (6) ◽  
pp. 481-492 ◽  
Author(s):  
Keiichi Kanda ◽  
Takehisa Matsuda

The effect of tensile stress on the orientation and phenotype of arterial smooth muscle cells (SMCs) cultured in three-dimensional (3D) type I collagen gels was morphologically investigated. Ring-shaped hybrid tissues were prepared by thermal gelation of a cold mixed solution of type I collagen and SMCs derived from bovine aorta. The tissues were subjected to three different modes of tensile stress. They were floated (isotonic control), stretched isometrically (static stress) and periodically stretched and recoiled by 5% above and below the resting tissue length at 60 RPM frequency (dynamic stress). After incubation for up to four wk, the tissues were investigated under a light microscope (LM) and a transmission electron microscope (TEM). Hematoxylin and eosinstained LM samples revealed that, irrespective of static or dynamic stress loading, SMCs in stress-loaded tissues exhibited elongated bipolar spindle shape and were regularly oriented parallel to the direction of the strain, whereas those in isotonic control tissues were polygonal or spherical and had no preferential orientation. In Azan-stained samples, collagen fiber bundles in isotonic control tissues were somewhat retracted around the polygonal SMCs to form a random network. On the other hand, those in statically and dynamically stressed tissues were accumulated and prominently oriented parallel to the stretch direction. Ultrastructural investigation using a TEM showed that SMCs in control and statically stressed tissues were almost totally filled with synthetic organelles such as rough endoplasmic reticulums, free ribosomes, Golgi complexes and mitochondria, indicating that the cells remained in the synthetic phenotype. On the other hand, SMCs in dynamically stressed tissues had increased fractions of contractile apparatus, such as myofilaments, dense bodies and extracellular filamentous materials equivalent to basement membranes, that progressed with incubation time. These results indicate that periodic stretch, in concert with 3-D extracellular collagen matrices, play a significant role in the phenotypic modulation of SMCs from the synthetic to the contractile state, as well as cellular and biomolecular orientation.


Author(s):  
Lowell T. Edgar ◽  
Steve A. Maas ◽  
James E. Guilkey ◽  
Jeffrey A. Weiss

Recent developments in tissue engineering have created demand for the ability to create microvascular networks with specific topologies in vitro. During angiogenesis, sprouting endothelial cells apply traction forces and migrate along components of the extracellular matrix (ECM), resulting in neovessel elongation [1]. The fibrillar structure of the ECM serves as the major pathway for mechanotransduction between contact-dependent cells. Using a three-dimensional (3D) organ culture model of microvessel fragments within a type-I collagen gel, we have shown that subjecting the culture to different boundary conditions during angiogenesis can lead to drastically different vascular topologies [2]. Fragments cultured in a rectangular gel that were free to contract grew into a randomly oriented network [3, 4]. When the long-axis of the gel was constrained as to prevent contraction, microvessels and collagen fibers were found aligned along the constrained axis (Fig. 1) [4].


2019 ◽  
Vol 20 (11) ◽  
pp. 2734 ◽  
Author(s):  
Young Hun Lee ◽  
Eun Kyoung Seo ◽  
Seung-Taek Lee

Skullcapflavone II is a flavonoid derived from the root of Scutellaria baicalensis, a herbal medicine used for anti-inflammatory and anti-cancer therapies. We analyzed the effect of skullcapflavone II on the expression of matrix metalloproteinase-1 (MMP-1) and integrity of type I collagen in foreskin fibroblasts. Skullcapflavone II did not affect the secretion of type I collagen but reduced the secretion of MMP-1 in a dose- and time-dependent manner. Real-time reverse transcription-PCR and reporter gene assays showed that skullcapflavone II reduced MMP-1 expression at the transcriptional level. Skullcapflavone II inhibited the serum-induced activation of the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways required for MMP-1 transactivation. Skullcapflavone II also reduced tumor necrosis factor (TNF)-α-induced nuclear factor kappa light chain enhancer of activated B cells (NF-κB) activation and subsequent MMP-1 expression. In three-dimensional culture of fibroblasts, skullcapflavone II down-regulated TNF-α-induced MMP-1 secretion and reduced breakdown of type I collagen. These results indicate that skullcapflavone II is a novel biomolecule that down-regulates MMP-1 expression in foreskin fibroblasts and therefore could be useful in therapies for maintaining the integrity of extracellular matrix.


2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Jinjin Ma ◽  
Kristen Goble ◽  
Michael Smietana ◽  
Tatiana Kostrominova ◽  
Lisa Larkin ◽  
...  

The incidence of ligament injury has recently been estimated at 400,000/year. The preferred treatment is reconstruction using an allograft, but outcomes are limited by donor availability, biomechanical incompatibility, and immune rejection. The creation of an engineered ligament in vitro solely from patient bone marrow stromal cells (has the potential to greatly enhance outcomes in knee reconstructions. Our laboratory has developed a scaffoldless method to engineer three-dimensional (3D) ligament and bone constructs from rat bone marrow stem cells in vitro. Coculture of these two engineered constructs results in a 3D bone-ligament-bone (BLB) construct with viable entheses, which was successfully used for medial collateral ligament (MCL) replacement in a rat model. 1 month and 2 month implantations were applied to the engineered BLBs. Implantation of 3D BLBs in a MCL replacement application demonstrated that our in vitro engineered tissues grew and remodeled quickly in vivo to an advanced phenotype and partially restored function of the knee. The explanted 3D BLB ligament region stained positively for type I collagen and elastin and was well vascularized after 1 and 2 months in vivo. Tangent moduli of the ligament portion of the 3D BLB 1 month explants increased by a factor of 2.4 over in vitro controls, to a value equivalent to those observed in 14-day-old neonatal rat MCLs. The 3D BLB 1 month explants also exhibited a functionally graded response that closely matched native MCL inhomogeneity, indicating the constructs functionally adapted in vivo.


2004 ◽  
Vol 167 (4) ◽  
pp. 757-767 ◽  
Author(s):  
Tae-Hwa Chun ◽  
Farideh Sabeh ◽  
Ichiro Ota ◽  
Hedwig Murphy ◽  
Kevin T. McDonagh ◽  
...  

During angiogenesis, endothelial cells initiate a tissue-invasive program within an interstitial matrix comprised largely of type I collagen. Extracellular matrix–degradative enzymes, including the matrix metalloproteinases (MMPs) MMP-2 and MMP-9, are thought to play key roles in angiogenesis by binding to docking sites on the cell surface after activation by plasmin- and/or membrane-type (MT) 1-MMP–dependent processes. To identify proteinases critical to neovessel formation, an ex vivo model of angiogenesis has been established wherein tissue explants from gene-targeted mice are embedded within a three-dimensional, type I collagen matrix. Unexpectedly, neither MMP-2, MMP-9, their cognate cell-surface receptors (i.e., β3 integrin and CD44), nor plasminogen are essential for collagenolytic activity, endothelial cell invasion, or neovessel formation. Instead, the membrane-anchored MMP, MT1-MMP, confers endothelial cells with the ability to express invasive and tubulogenic activity in a collagen-rich milieu, in vitro or in vivo, where it plays an indispensable role in driving neovessel formation.


Sign in / Sign up

Export Citation Format

Share Document