Notch signaling pathway induces expression of type IV collagen in angiogenesis.

Mural cell adhesion is important for the localization of basement membrane components during angiogenesis, and cell-cell interactions are thought to be critical for basement membrane formation. Type IV collagen, a component of the basement membrane, and non-triple helical type IV collagen α1 chain (NTH α1(IV)) co-localize in the basement membrane of neovascular vessels. However, it remains unclear how type IV collagen and NTH α1(IV) are produced around the basement membrane.

Non-triple helical form of type IV collagen alpha1 chain suppresses vascular endothelial-cadherin mediated cell-to-cell junctions.

Non-triple helical collagen polypeptide α1(IV) (NTH α1(IV)) is a gene product of COL4A1 and is secreted as a polypeptide chain without the triple helix structure under physiological conditions. Studies have shown that NTH α1(IV) is up-regulated in and around vascular endothelial cells during neovascularization and vascular-like networks of in vitro angiogenesis models, suggesting its involvement in angiogenesis. In the present study, we examined the effect of NTH α1(IV) on endothelial cell-to-cell junctions, and we found that NTH α1(IV) suppressed VE-cadherin (vascular endothelial cadherin) mediated junctions and promoted cellular migration in human umbilical vein endothelial cell cultures.

Synthesis and characterization of PNA oligomers containing preQ as a positively charged guanine analogue.

We report the synthesis of a peptide nucleic acid (PNA) monomer containing preQ, a positively charged guanine analogue. The new monomer was incorporated into PNA oligomers using standard Fmoc-chemistry-based solid-phase synthesis. The preQ unit-containing PNA oligomers exhibited improved affinity for their complementary DNA through electrostatic attraction, and their sequence specificity was not compromised.

Involvement of non‑triple helical type VI collagen α1 chain, NTH α1(VI), in the proliferation of cancer cells.

It has been reported that a polypeptide encoded by collagen type VI alpha 1 chain (COL6A1), one of the three α chains of type VI collagen, is strongly associated with the migration and invasion of highly metastatic human pancreatic cancer BxPC‑M8 cells and excessive proliferation of LNCaP cells. We previously reported that non‑triple helical type VI collagen α1 chain, NTH α1(VI), a non‑triple helical polypeptide encoded by COL6A1, is not derived from type VI collagen and exists in cancer cell‑conditioned media. Therefore, NTH α1(VI) may be involved in cancer cell migration, invasion, and proliferation.

Excessively activated plasminogen in human plasma cleaves VWF multimers and reduces collagen-binding activity.

Plasmin (Pm) is a serine protease that can dissolve fibrin clots. Several possible functions of Pm in blood other than fibrinolysis have been proposed. To explore the effects of Pm on primary haemostasis, we evaluated the cleavage of von Willebrand factor multimers (VWFMs) in human plasma by streptokinase (SK)-activated plasminogen (Pg) and the binding ability of the digested VWFMs to collagen.

Basement membrane-like structures containing NTH α1(IV) are formed around the endothelial cell network in a novel in vitro angiogenesis model.

Angiogenesis is a process through which new blood vessels are formed by sprouting and elongating from existing blood vessels. Several methods have been used to replicate angiogenesis in vitro, including culturing vascular endothelial cells on Matrigel and coculturing with endothelial cells and fibroblasts. However, the angiogenesis elongation process has not been completely clarified in these models.

Silibinin's regulation of proliferation and collagen gene expressions of rat pancreatic β-cells cultured on types I and V collagen involves β-catenin nuclear translocation.

Extracellular matrix (ECM) molecules have multiple functions; prevention of cytotoxicity, provision of mechanical support, cell adhesive substrates and structural integrity in addition to mediation of cellular signaling. In this study, we report that the proliferation of INS-1 cells cultured on collagen I-coated dishes is enhanced, but it is inhibited on collagen V-coated dishes. Inhibitory proliferation on collagen V-coated is not due to apoptosis induction.

Identification of a common epitope in the sequences of COL4A1 and COL6A1 recognized by monoclonal antibody #141.

Identification of a type IV collagen α1 polypeptide in non-triple helical form [NTH α1(IV)], possibly involved in angiogenesis, introduces the further possibility of the existence of non-triple helical forms of other collagen chains. We previously reported that an anti-NTH α1(IV) monoclonal antibody #141 recognizes not only NTH α1(IV) but also a novel non-triple helical collagen polypeptide NTH α1(VI) encoded by COL6A1. In this study, we identified the recognition sequence in order to better understand the properties of antibody #141 and provide clues regarding the biological function of the two non-triple helical molecules.

Type VI collagen α1 chain polypeptide in non-triple helical form is an alternative gene product of COL6A1.

Expression of type IV collagen α1 chain in non-triple helical form, NTH α1(IV), is observed in cultured human cells, human placenta and rabbit tissues. Biological functions of NTH α1(IV) are most likely to be distinct from type IV collagen, since their biochemical characteristics are quite different. To explore the biological functions of NTH α1(IV), we prepared some anti-NTH α1(IV) antibodies.

Acidic Chitinase-Chitin Complex Is Dissociated in a Competitive Manner by Acetic Acid: Purification of Natural Enzyme for Supplementation Purposes.

Acidic chitinase (Chia) has been implicated in asthma, allergic inflammations, and food processing. We have purified Chia enzymes with striking acid stability and protease resistance from chicken and pig stomach tissues using a chitin column and 8 M urea (urea-Chia). Here, we report that acetic acid is a suitable agent for native Chia purification from the stomach tissues using a chitin column (acetic acid-Chia).

Proteolytic inactivation of ADAMTS13 by plasmin in human plasma: risk of thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is caused by inactivation of a von Willebrand factor (VWF)-cleaving enzyme, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), which leads to platelet-rich thrombi comprising unusually large VWF multimers. We have found that ADAMTS13 can bind to the inactivated form of plasmin. In addition, plasmin cleaves purified ADAMTS13 into several fragments and inactivates it.

Preparation and partial characterization of monoclonal antibodies specific for the nascent non-triple helical form of the type IV collagen alpha 1 chain.

This report describes the preparation and partial characterization of monoclonal antibodies that are reactive specifically with the nascently produced non-triple helical form of the type IV collagen α1 chain, designated as NTH α1(IV). These antibodies were nonreactive with the α1 chain of the type IV collagen in the triple-helical conformation. Three antibodies, #141, #179 and #370, with different epitopes in NTH α1(IV) were found to be reactive with the nascent polypeptide secreted from human normal cells and a human carcinoma cell line.

PNA monomers fully compatible with standard Fmoc-based solid-phase synthesis of pseudocomplementary PNA.

Here we report the synthesis of new PNA monomers for pseudocomplementary PNA (pcPNA) that are fully compatible with standard Fmoc chemistry. The thiocarbonyl group of the 2-thiouracil (sU) monomer was protected with the 4-methoxy-2-methybenzyl group (MMPM), while the exocyclic amino groups of diaminopurine (D) were protected with Boc groups. The newly synthesized monomers were incorporated into a 10-mer PNA oligomer using standard Fmoc chemistry for solid-phase synthesis.

Ring-Mesh Model of Proteoglycan Glycosaminoglycan Chains in Tendon based on Three-dimensional Reconstruction by Focused Ion Beam Scanning Electron Microscopy.

Tendons are composed of collagen fibrils and proteoglycan predominantly consisting of decorin. Decorin is located on the d-band of collagen fibrils, and its glycosaminoglycan (GAG) chains have been observed between collagen fibrils with transmission electron microscopy. GAG chains have been proposed to interact with each other or with collagen fibrils, but its three-dimensional organization remains unclear.

Non-Triple Helical Form of Type IV Collagen α1 Chain.

Type IV collagen with a triple-helical structure composed of three α chains is a major component of basement membrane. Previously, we reported that non-triple helical form of type IV collagen α1 chain (NTHα1(IV)) was isolated from human placenta and the culture media of human cells. In the present study, we report on the localization of NTH α1(IV) with a monoclonal antibody #370, exclusively reactive for the nascent chain, in the rabbit tissues.

Peptide Nucleic Acid with a Lysine Side Chain at the β-Position: Synthesis and Application for DNA Cleavage.

This paper reports the synthesis of new β-Lys peptide nucleic acid (PNA) monomers and their incorporation into a 10-residue PNA sequence. PNA containing β-Lys PNA units formed a stable hybrid duplex with DNA. However, incorporation of β-Lys PNA units caused destabilization of PNA-DNA duplexes to some extent.

Synthesis and evaluation of a cyclopropane derivative of DHMEQ.

Dehydroxymethylepoxyquinomycin (DHMEQ, 1) is well known to inhibit nuclear factor-kappa B (NF-κB), which is closely associated with immune, inflammatory, and apoptotic processes as an inducible transcription factor. The inhibitory effect seems to be the result of the ring opening of an epoxide of 1 with Cys(38) of p65. We have synthesized an analog 4 containing a cyclopropanated quinol skeleton and examined its ability to inhibit NF-κB.

Fragility of reconstituted type V collagen fibrils with the chain composition of α1(V)α2(V)α3(V) respective of the D-periodic banding pattern.

The triple-helical domains of two subtypes of type V collagen were prepared from human placenta, one with the chain composition of [α1(V)](2)α2(V) (Vp112) and the other with the chain composition of α1(V)α2(V)α3(V) (Vp123) with limited pepsin treatment. In order to characterize the triple-helical domain of the type Vp123 collagen molecule, the reconstituted aggregate structure formed from the pepsin-treated collagen was compared by using transmission electron microscopy. The diameter of the fibrils reconstituted from types pepsin-treated type Vp123 collagen and type Vp112 collagen was highly uniform and less than the D-periodicity at all the temperatures examined, suggesting that the major triple-helical domain of both subtypes has a potency to limit their lateral growth.

Concerted and adaptive alignment of decorin dermatan sulfate filaments in the graded organization of collagen fibrils in the equine superficial digital flexor tendon.

The equine superficial digital flexor tendon (SDFT) has a graded distribution of collagen fibril diameters, with predominantly small-diameter fibrils in the region of the myotendinous junction (MTJ), a gradual increase in large-diameter fibrils toward the osteotendinous junction (OTJ), and a mixture of small- and large-diameter fibrils in the middle metacarpal (MM) region. In this study, we investigated the ultrastructure of the SDFT, to correlate the spatial relationship of the collagen fibrils with the graded distribution. The surface-to-surface distances of pairs of fibrils were found to be almost constant over the entire tendon.

β-PNA: peptide nucleic acid (PNA) with a chiral center at the β-position of the PNA backbone.

Peptide nucleic acid (PNA) monomers with a methyl group at the β-position have been synthesized. The modified monomers were incorporated into PNA oligomers using Fmoc chemistry for solid-phase synthesis. Thermal denaturation and circular dichroism (CD) studies have shown that PNA containing the S-form monomers was well suited to form a hybrid duplex with DNA, whose stability was comparable to that of unmodified PNA-DNA duplex, whereas PNA containing the R-form monomers was not.

ELISA measurement for urinary 3-hydroxyproline-containing peptides and its preliminary application to healthy persons and cancer patients.

Background/aim: We reported that endogenous urinary 3-hydroxyproline (3-Hyp) is useful for cancer screening because cancer invasion involves the destruction of basement membrane. A simple and sensitive assay is desired.

Patients And Methods: An ELISA method using a specific antibody against a synthetic peptide of 10 amino acids including 3-Hyp corresponding to the amino acid sequences of collagen type IV alpha chain was applied to urine samples from 180 healthy controls and 22 cancer patients.

Intercellular accumulation of type V collagen fibrils in accordance with cell aggregation.

We reported previously that human fibroblasts form clumps when cultured on a dish coated with reconstituted type V collagen fibrils. Essentially all the type V collagen fibrils, initially coated on the dish, were recovered in the cell clumps that had eventually formed during the culture. We interpreted that type V collagen fibrils adhere to cells more strongly than to the dish and are detached by cell movements.

Collagen-type specificity of glycoprotein VI as a determinant of platelet adhesion.

Of the two physiologically important platelet collagen receptors, glycoprotein (GP) VI is the receptor responsible for platelet activation. However, its reactivities towards different types of vascular collagen have not been directly and quantitatively analysed with collagen preparations of defined composition, although the other major platelet collagen receptor integrin alpha(2)beta(1) was shown to react with collagen types I-VI and VIII under either static or flow conditions. We analysed the collagen type specificity of GPVI binding to identify the physiological contribution of the various vascular collagens and how platelet reactivity towards the various collagens may be affected by fibril size.

Graded arrangement of collagen fibrils in the equine superficial digital flexor tendon.

By using ultramorphological and biochemical methods, we analyzed the regional differences between the three parts of the equine superficial digital flexor tendon (SDFT), namely, the myotendinous junction (MTJ), middle metacarpal (mM), and osteotendinous junction (OTJ). Cross-sectional images showed unique distributions of collagen fibrils of varying diameters in each region. Small collagen fibrils (diameter <100 nm) were distributed predominantly in the MTJ region, and the OTJ region was relatively rich in large collagen fibrils (diameter >200 nm).