Structure and biological activity of basement membrane proteins

Matrix remodeling in chronic lung diseases

Multicellular organisms synthesize and renew components of their subcellular and scaffolding proteins, collectively known as the extracellular matrix molecules (ECMs). In the lung, ECMs maintain tensile strength, elasticity, and dictate the specialized function of multiple cell lineages. These functions are critical in lung homeostatic processes including cellular migration and proliferation during morphogenesis or in response to repair. Alterations in lung ECMs that expose cells to new cryptic fragments, generated in response to endogenous proteinases or exogenous toxins, are associated with the development of several common respiratory diseases. How lung ECMs provide or relay vital signals to epithelial and mesenchymal cells has shed new light on development and progression of several common chronic respiratory diseases. This review will consider how ECMs regulate lung homeostasis and their reorganization under pathological conditions that can modulate the inflammatory diseases asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). Better understanding of changes in the distribution of lung ECM could provide novel therapeutic approaches to treat chronic lung diseases.

Glomerular endothelial cells versus podocytes as the cellular target in diabetic nephropathy

It usually takes several years (in some cases, decades) for predisposed individuals to move from the onset of type 1 or type 2 diabetes to the development of microalbuminuria, the first sign of diabetic nephropathy. This long, complication-free, period represents the best possible moment to start a successful preventive strategy (primary prevention) aimed to avoid or at least to postpone the increase of albumin excretion rate. Prevention is based on understanding and counteracting the initial mechanisms leading to the development of the disease and unfortunately, in case of diabetic nephropathy, most of them remain unclear. Little is also known about which, among endothelial cells and podocytes, represent the first glomerular target of the complication. Selective damage of the endothelium or of the podocyte results, as a common consequence, in an increase of albumin excretion rate. Albuminuria by itself cannot therefore be of help to solve the case. Endothelium and podocytes are involved in a continuous cross-talk and by studying the impact of diabetes on this "communication" process it should be possible to obtain some information regarding the weak component of the glomerular filter. Finally, the careful investigation of the mechanisms leading to the development podocyturia, a recently identified glomerular dysfunction associated to the pathogenesis of diabetic nephropathy, could contribute to shed some more light on the very early stages of this complication.

Basement membranes in the cornea and other organs that commonly develop fibrosis

Basement membranes are thin connective tissue structures composed of organ-specific assemblages of collagens, laminins, proteoglycan-like perlecan, nidogens, and other components. Traditionally, basement membranes are thought of as structures which primarily function to anchor epithelial, endothelial, or parenchymal cells to underlying connective tissues. While this role is important, other functions such as the modulation of growth factors and cytokines that regulate cell proliferation, migration, differentiation, and fibrosis are equally important. An example of this is the critical role of both the epithelial basement membrane and Descemet's basement membrane in the cornea in modulating myofibroblast development and fibrosis, as well as myofibroblast apoptosis and the resolution of fibrosis. This article compares the ultrastructure and functions of key basement membranes in several organs to illustrate the variability and importance of these structures in organs that commonly develop fibrosis.

A novel biomarker of laminin turnover is associated with disease progression and mortality in chronic kidney disease

Background

Patients with chronic kidney disease (CKD) have increased risk of development of end-stage renal disease (ESRD) and early mortality. Fibrosis is the central pathogenic process in CKD and is caused by dysregulated extracellular matrix (ECM) remodeling. The laminin γ1 chain (LAMC1) is a core structural protein present in the basement membrane of several organs, including the kidneys. We hypothesized that dysregulation of LAMC1 remodeling could be associated with a higher risk of adverse clinical outcomes in patients with CKD.

Methods

A novel immunoassay targeting LG1M, a specific MMP-9-generated neo-epitope fragment of LAMC1, was developed and used to measure the levels of the fragment in urine and serum from 492 patients from the Renal Impairment in Secondary Care (RIISC) study, a prospective cohort of patients with high-risk CKD. Patients were monitored for a median follow-up time of 3.5 years. Associations between serum and urine LG1M levels and progression of CKD at 12 months were assessed by a multivariable logistic regression model. The association with ESRD or mortality was assessed by Kaplan-Meier survival curves and Cox proportional hazards regression.

Results

Forty-six (11%) of the 416 patients who reached 12-month follow-up had progression of CKD; during the study follow-up, 125 patients (25.4%) developed ESRD and 71 patients (14.4%) died. Serum and urine levels of LG1M correlated with baseline eGFR (r = -0.43, p<0.0001 and r = -0.17, p = 0.0002, respectively). Serum levels of LG1M were higher in patients with one-year progression of CKD compared to those who did not progress (p<0.01). Baseline serum levels of LG1M were associated with development of ESRD (HR 3.2, 95% CI 1.99–5.2 for patients in the highest LG1M tertile compared to patient in the lowest tertile). Baseline urinary levels of LG1M (uLG1M) were significantly associated with mortality (HR 5.0, 95% CI 2.8–8.9, p<0.0001 for patients in the highest LG1M tertile compared to patients in the lowest tertile). Urine LG1M was retained in the model for prediction of mortality (HR per standard deviation of uLG1M: 1.01, 95% CI 1.00–1.02, p = 0.001).

Conclusions

LG1M, a marker of basement membrane remodeling, is increased in serum and urine of patients with CKD and levels are associated with one-year disease progression, development of ESRD, and mortality.

Renal Tubular- and Vascular Basement Membranes and their Mimicry in Engineering Vascularized Kidney Tubules

The high prevalence of chronic kidney disease leads to an increased need for renal replacement therapies. While there are simply not enough donor organs available for transplantation, there is a need to seek other therapeutic avenues as current dialysis modalities are insufficient. The field of regenerative medicine and whole organ engineering is emerging, and researchers are looking for innovative ways to create (part of) a functional new organ. To biofabricate a kidney or its functional units, it is necessary to understand and learn from physiology to be able to mimic the specific tissue properties. Herein is provided an overview of the knowledge on tubular and vascular basement membranes' biochemical components and biophysical properties, and the major differences between the two basement membranes are highlighted. Furthermore, an overview of current trends in membrane technology for developing renal replacement therapies and to stimulate kidney regeneration is provided.

A Microfluidic System for the Investigation of Tumor Cell Extravasation

Metastatic dissemination of cancer cells is a very complex process. It includes the intravasation of cells into the metastatic pathways, their passive distribution within the blood or lymph flow, and their extravasation into the surrounding tissue. Crucial steps during extravasation are the adhesion of the tumor cells to the endothelium and their transendothelial migration. However, the molecular mechanisms that are underlying this process are still not fully understood. Novel three dimensional (3D) models for research on the metastatic cascade include the use of microfluidic devices. Different from two dimensional (2D) models, these devices take cell⁻cell, structural, and mechanical interactions into account. Here we introduce a new microfluidic device in order to study tumor extravasation. The device consists of three different parts, containing two microfluidic channels and a porous membrane sandwiched in between them. A smaller channel together with the membrane represents the vessel equivalent and is seeded separately with primary endothelial cells (EC) that are isolated from the lung artery. The second channel acts as reservoir to collect the migrated tumor cells. In contrast to many other systems, this device does not need an additional coating to allow EC growth, as the primary EC that is used produces their own basement membrane. VE-Cadherin, an endothelial adherence junction protein, was expressed in regular localization, which indicates a tight barrier function and cell⁻cell connections of the endothelium. The EC in the device showed in vivo-like behavior under flow conditions. The GFP-transfected tumor cells that were introduced were of epithelial or mesenchymal origin and could be observed by live cell imaging, which indicates tightly adherent tumor cells to the endothelial lining under different flow conditions. These results suggest that the new device can be used for research on molecular requirements, conditions, and mechanism of extravasation and its inhibition.

Immunohistochemical Distribution of Basement Membrane Type IV Collagen and Laminin in Synovial Sarcoma

Aims

To investigate the distribution of basement membrane components type IV collagen and laminin in synovial sarcomas.

Methods

Paraffin sections from four synovial sarcomas were studied by the peroxidase-antiperoxldase procedure using specific antibodies to type IV collagen and laminin.

Results

Type IV collagen and laminin immunoreactivity was confined around epithelial areas in biphasic tumors. Several interruptions and discontinuities of the linear basement membrane profile were seen in sites of transition between mesenchymal and epithelial tissue. Moreover, a spot-like immunoreactivity was often observed in the spindle cell component of biphasic tumors. Monophasic tumors were either negative or showed a pericellular staining for both type IV collagen and laminin.

Conclusions

The distribution of basement membrane components is clearly related to the formation of epithelial elements in biphasic synovial sarcoma. The spot-like immunoreactivity of the spindle cell component, and the basement membrane interruptions at the boundary between mesenchymal and epithelial tissue, are both consistent with early basement membrane formation by developing epithelium. These findings support the concept that synovial sarcomas are basically soft tissue carcinosarcomas and that the epithelial component of the tumors develops by conversion of mesenchyme to epithelium.

The Basement Membranes in Sarcomatoid Carcinomas. An Immunohistochemical Study

Aims

Eight sarcomatoid carcinomas from various anatomical locations were investigated by immunohistochemical staining to laminin, type IV collagen and heparan sulfate proteoglycan, to study the characteristics of basement membranes at the interface between carcinomatous and sarcomatous tissues.

Methods

Paraffin wax embedded tissue sections from representative tumor samples have been stained with specific antibodies, using the peroxidase-antiperoxidase technique.

Results

In all cases several interruptions or discontinuities of the basement membrane staining pattern were seen. In 4 cases, larger defects or complete loss of staining was also noted. At these places, the boundaries between carcinomatous and sarcomatous tissue were often blurred.

Conclusions

Disruption and loss of basement membranes at interface between carcinomatous and sarcomatous tissues is a frequent finding in sarcomatoid carcinomas. These changes could be consistent with an epithelial origin of the sarcomatous component in these tumors by means of an epithelial-mesenchymal conversion mechanism.

A role for collagen type IV in cardiovascular disease?

Over the past decade, studies have repeatedly found single-nucleotide polymorphisms located in the collagen ( COL) 4A1 and COL4A2 genes to be associated with cardiovascular disease (CVD), and the 13q34 locus harboring these genes is one of ~160 genome-wide significant risk loci for coronary artery disease. COL4A1 and COL4A2 encode the α₁- and α₂-chains of collagen type IV, a major component of basement membranes in various tissues including arteries. Despite the growing body of evidence indicating a role for collagen type IV in CVD, remarkably few studies have aimed to directly investigate such a role. The purpose of this review is to summarize the clinical reports linking 13q34 to coronary artery disease, atherosclerosis, and artery stiffening and to assemble the scattered pieces of evidence from experimental studies based on vascular cells and tissue collectively supporting a role for collagen type IV in atherosclerosis and other macrovascular disease conditions.

Long-Term Improvement in Aortic Pulse Wave Velocity After Weight Loss Can Be Predicted by White Adipose Tissue Factors

BACKGROUND

Arterial stiffness, measured by pulse wave velocity (PWV), is linked to obesity, cardiovascular disease, and all-cause mortality. Short-term weight loss improves PWV, but the long-term effects are unknown. We investigated the effect of pronounced long-term weight loss on PWV and whether anthropometric/metabolic parameters and/or white adipose tissue (WAT) phenotype could predict this change in PWV.

METHODS

Eighty-two obese subjects were examined before and 2 years after Roux-en-Y gastric bypass. Analyses included anthropometrics, routine clinical chemistry, and hyperinsulinemic-euglycemic clamp. Arterial stiffness was measured as aortic PWV (aPWV) using the Arteriograph device. WAT mass and distribution were assessed by dual-X-ray absorptiometry. Baseline visceral and subcutaneous WAT samples were obtained to measure adipocyte cell size. Transcriptomic profiling of subcutaneous WAT was performed in a subset of subjects (n = 30).

RESULTS

At the 2-year follow-up, there were significant decreases in body mass index (39.4 ± 3.5 kg/m2 vs. 26.6 ± 3.4 kg/m2; P < 0.0001) and aPWV (7.8 ± 1.5 m/s vs. 7.2 ± 1.4 m/s; P = 0.006). Multiple regression analyses showed that baseline subcutaneous adipocyte volume was associated with a reduction in aPWV (P = 0.014), after adjusting for confounders. Expression analyses of 52 genes implicated in arterial stiffness showed that only one, COL4A1, independently predicted improvements in aPWV after adjusting for confounders (P = 0.006).

CONCLUSIONS

Bariatric surgery leads to long-term reduction in aPWV. This improvement can be independently predicted by subcutaneous adipocyte volume and WAT COL4A1 expression, which suggests that subcutaneous WAT has a role in regulating aPWV.

CLINICAL TRIALS REGISTRATION

Trial Number NCT01727245 (clinicaltrials.gov).

Glucuronylated core 1 glycans are required for precise localization of neuromuscular junctions and normal formation of basement membranes on Drosophila muscles

T antigen (Galβ1-3GalNAcα1-Ser/Thr) is an evolutionary-conserved mucin-type core 1 glycan structure in animals synthesized by core 1 β1,3-galactosyltransferase 1 (C1GalT1). Previous studies showed that T antigen produced by Drosophila C1GalT1 (dC1GalT1) was expressed in various tissues and dC1GalT1 loss in larvae led to various defects, including decreased number of circulating hemocytes, hyper-differentiation of hematopoietic stem cells in lymph glands, malformation of the central nervous system, mislocalization of neuromuscular junction (NMJ) boutons, and ultrastructural abnormalities in NMJs and muscle cells. Although glucuronylated T antigen (GlcAβ1-3Galβ1-3GalNAcα1-Ser/Thr) has been identified in Drosophila, the physiological function of this structure has not yet been clarified. In this study, for the first time, we unraveled biological roles of glucuronylated T antigen. Our data show that in Drosophila, glucuronylation of T antigen is predominantly carried out by Drosophila β1,3-glucuronyltransferase-P (dGlcAT-P). We created dGlcAT-P null mutants and found that mutant larvae showed lower expression of glucuronylated T antigen on the muscles and at NMJs. Furthermore, mislocalization of NMJ boutons and a partial loss of the basement membrane components collagen IV (Col IV) and nidogen (Ndg) at the muscle 6/7 boundary were observed. Those two phenotypes were correlated and identical to previously described phenotypes in dC1GalT1 mutant larvae. In addition, dGlcAT-P null mutants exhibited fewer NMJ branches on muscles 6/7. Moreover, ultrastructural analysis revealed that basement membranes that lacked Col IV and Ndg were significantly deformed. We also found that the loss of dGlcAT-P expression caused ultrastructural defects in NMJ boutons. Finally, we showed a genetic interaction between dGlcAT-P and dC1GalT1. Therefore, these results demonstrate that glucuronylated core 1 glycans synthesized by dGlcAT-P are key modulators of NMJ bouton localization, basement membrane formation, and NMJ arborization on larval muscles.

NIDO, AMOP and vWD domains of MUC4 play synergic role in MUC4 mediated signaling

MUC4 mucin is well known as an important potential target to overcome pancreatic cancer. Three unique domains (NIDO, AMOP, and vWD) with unclear roles only present in MUC4 but are not found in other membrane-bound mucins. Our previous studies first reported that its splice variant, MUC4/Y can be a model of MUC4 (MUC4 gene fragment is more than 30KB, too huge to clone and eukaryotic express) in pancreatic cancer. More importantly, based on MUC4/Y with the appropriate length of gene sequence, it is easy to construct the unique domain-lacking models of MUC4/Y (MUC4) for research. The present study focuses on investigation of the respective role of the unique NIDO, AMOP, and vWD domain or their synergistic effect on MUC4(MUC4/Y)-mediated functions and mechanisms by series of in vitro assays, sequence-based transcriptome analysis, validation of qRT-PCR & Western blot, and systematic comparative analysis. Our results demonstrate: 1) NIDO, AMOP, and vWD domain or their synergy play significant roles on MUC4/Y-mediated malignant function of pancreatic cancer, downstream of molecule mechanisms, particularly MUC4/Y-triggered malignancy-related positive feedback loops, respectively. 2) The synergistic roles of three unique domains on MUC4/Y-mediated functions and mechanisms are more prominent than the respective domain because the synergy of three domain plays the more remarkable effects on MUC4/Y-mediated signaling hub. Thus, to improve reversed effects of domain-lacking and break the synergism of domains will contribute to block MUC4/Y(MUC4) triggering various oncogenic signaling pathways.

Characterization of the structure, cells, and cellular mechanobiological response of human plantar fascia

In this study, we report that human plantar fascia consists of two distinct tissues with differential structural properties. These tissues also contain stem/progenitor cells with differential biological properties. The mechanobiological responses of these two plantar fascia stem cells also differ in terms of expression of collagen I and IV, non-ligament-related genes, and proinflammatory genes. The production of inflammatory agents (prostaglandin E2, interleukin-6) and matrix degradative enzymes (matrix metalloproteinase-1, matrix metalloproteinase-2) are also different between the two types of plantar fascia stem cells. Based on the findings from this study, we suggest that plantar fasciitis results from the aberrant mechanobiological responses of the stem cells from plantar fascia sheath and core tissues. Our findings may also be used to devise tissue engineering approaches to treat plantar fascia injury effectively.

Basement Membrane Defects in Genetic Kidney Diseases

The glomerular basement membrane (GBM) is a specialized structure with a significant role in maintaining the glomerular filtration barrier. This GBM is formed from the fusion of two basement membranes during development and its function in the filtration barrier is achieved by key extracellular matrix components including type IV collagen, laminins, nidogens, and heparan sulfate proteoglycans. The characteristics of specific matrix isoforms such as laminin-521 (α5β2γ1) and the α3α4α5 chain of type IV collagen are essential for the formation of a mature GBM and the restricted tissue distribution of these isoforms makes the GBM a unique structure. Detailed investigation of the GBM has been driven by the identification of inherited abnormalities in matrix proteins and the need to understand pathogenic mechanisms causing severe glomerular disease. A well-described hereditary GBM disease is Alport syndrome, associated with a progressive glomerular disease, hearing loss, and lens defects due to mutations in the genes COL4A3, COL4A4, or COL4A5. Other proteins associated with inherited diseases of the GBM include laminin β2 in Pierson syndrome and LMX1B in nail patella syndrome. The knowledge of these genetic mutations associated with GBM defects has enhanced our understanding of cell-matrix signaling pathways affected in glomerular disease. This review will address current knowledge of GBM-associated abnormalities and related signaling pathways, as well as discussing the advances toward disease-targeted therapies for patients with glomerular disease.

Engineered basement membranes: from in vivo considerations to cell-based assays

Engineered basement membranes are required to mimic in vivo properties within cell-based assays.

The vascular basement membrane in the healthy and pathological brain

The vascular basement membrane contributes to the integrity of the blood-brain barrier (BBB), which is formed by brain capillary endothelial cells (BCECs). The BCECs receive support from pericytes embedded in the vascular basement membrane and from astrocyte endfeet. The vascular basement membrane forms a three-dimensional protein network predominantly composed of laminin, collagen IV, nidogen, and heparan sulfate proteoglycans that mutually support interactions between BCECs, pericytes, and astrocytes. Major changes in the molecular composition of the vascular basement membrane are observed in acute and chronic neuropathological settings. In the present review, we cover the significance of the vascular basement membrane in the healthy and pathological brain. In stroke, loss of BBB integrity is accompanied by upregulation of proteolytic enzymes and degradation of vascular basement membrane proteins. There is yet no causal relationship between expression or activity of matrix proteases and the degradation of vascular matrix proteins in vivo. In Alzheimer's disease, changes in the vascular basement membrane include accumulation of Aβ, composite changes, and thickening. The physical properties of the vascular basement membrane carry the potential of obstructing drug delivery to the brain, e.g. thickening of the basement membrane can affect drug delivery to the brain, especially the delivery of nanoparticles.

Functional Hepatocyte Culture and its Application to Cell Therapies

Since Berry and Friend developed methods to isolate hepatocytes from the liver by a collagenase digestion technique in 1969, studies in laboratory animals have demonstrated that hepatocyte transplantation could potentially be used for the treatment of liver failure and inborn errors of liver-based metabolism. Healthy human hepatocytes are an ideal source for hepatocyte transplantation; however, their relative scarcity is one of the major drawbacks, further compounded by the competing demands of liver transplantation. Notably, most of the hepatocytes are isolated from discarded livers that are not suitable for organ transplantation for a variety of reasons, including excessive fat content. Importantly, the hepatocyte isolation procedure itself exerts major stress on hepatocytes by the disruption of cell-to-cell and cell-to-matrix contacts, resulting in hepatocytic apoptosis. Prevention of apoptosis would maximize yield of healthy cells and maintain hepatocyte differentiated function in culture. In this review, we describe methods to prevent apoptosis by utilizing both antiapoptotic molecules and matrices. We also introduce a new type of liver tissue engineering, hepatocyte sheet transplantation, which utilizes unwoven cloth having a cellular adhesive property.

Basement Membrane Type IV Collagen and Laminin: An Overview of Their Biology and Value as Fibrosis Biomarkers of Liver Disease

Basement membranes provide structural support to epithelium, endothelium, muscles, fat cells, Schwann cells, and axons. Basement membranes are multifunctional: they modulate cellular behavior, regulate organogenesis, promote tissue repair, form a barrier to filtration and tumor metastasis, bind growth factors, and mediate angiogenesis. All basement membranes contain type IV collagen (Col IV), laminin, nidogen, and perlecan. Col IV and laminin self-assemble into two independent supramolecular networks that are linked to nidogen and perlecan to form a morphological discernable basement membrane/basal lamina. The triple helical region, 7S domain and NCI domain of Col IV, laminin and laminin fragment P1 have been evaluated as noninvasive fibrosis biomarkers of alcoholic liver disease, viral hepatitis, and nonalcoholic fatty liver disease. Elevated serum Col IV and laminin are related to degrees of fibrosis and severity of hepatitis, and may reflect hepatic basement membrane metabolism. But the serum assays have not been linked to disclosing the anatomical sites and lobular distribution of perisinusoidal basement membrane formation in the liver. Hepatic sinusoids normally lack a basement membrane, although Col IV is a normal matrix component of the space of Disse. In liver disease, laminin deposits in the space of Disse and codistributes with Col IV, forming a perisinusoidal basement membrane. Concomitantly, the sinusoidal endothelium loses its fenestrae and is transformed into vascular type endothelium. These changes lead to capillarization of hepatic sinusoids, a significant pathology that impairs hepatic function. Accordingly, codistribution of Col IV and laminin serves as histochemical marker of perisinusoidal basement membrane formation in liver disease. Anat Rec, 300:1371-1390, 2017. © 2017 Wiley Periodicals, Inc.

Expression quantitative trait loci for PI3K/AKT pathway

A genome-wide association study (GWAS) was conducted to identify expression quantitative trait loci (eQTLs) for the genes involved in phosphatidylinositol-3-kinase/v-akt murine thymoma viral oncogene homolog (PI3K/AKT) pathway.Data on mRNA expression of 341 genes in lymphoblastoid cell lines of 373 Europeans recruited by the 1000 Genomes Project using Illumina HiSeq2000 were utilized. We used their genotypes at 5,941,815 nucleotide variants obtained by Genome Analyzer II and SOLiD.The association analysis revealed 4166 nucleotide variants associated with expression of 85 genes (P < 5 × 10). A total of 73 eQTLs were identified as association signals for the expression of multiple genes. They included 9 eQTLs for both of the genes encoding collagen type I alpha 1 (COL1A1) and integrin alpha 11 (ITGA11), which synthesize a major complex of plasma membrane. They also included eQTLs for type IV collagen molecules; 13 eQTLs for both collagen type IV alpha 1 (COL4A1) and collagen type IV alpha 2 (COL4A2) and 18 eQTLs for both collagen type IV alpha 5 (COL4A5) and collagen type IV alpha 6 (COL4A6). Some genes expressed by the eQTLs might induce expression of the genes encoding type IV collagen. One eQTL (rs16871986) was located in the promoter of palladin (PALLD) gene which might synthesize collagen by activating fibroblasts through the PI3K/AKT pathway. Another eQTL (rs34845474) was located in an enhancer of cadherin related family member 3 (CDHR3) gene which can mediate cell adhesion.This study showed a profile of eQTLs for the genes involved in the PI3K/AKT pathway using a healthy population, revealing 73 eQTLs associated with expression of multiple genes. They might be candidates of common variants in predicting genetic susceptibility to cancer and in targeting cancer therapy. Further studies are required to examine their underlying mechanisms for regulating expression of the genes.

Synthesis and deposition of basement membrane proteins by primary brain capillary endothelial cells in a murine model of the blood-brain barrier

The brain vascular basement membrane is important for both blood-brain barrier (BBB) development, stability, and barrier integrity and the contribution hereto from brain capillary endothelial cells (BCECs), pericytes, and astrocytes of the BBB is probably significant. The aim of this study was to analyse four different in vitro models of the murine BBB for expression and possible secretion of major basement membrane proteins from murine BCECs (mBCECs). mBCECs, pericytes and glial cells (mainly astrocytes and microglia) were prepared from brains of C57BL/6 mice. The mBCECs were grown as monoculture, in co-culture with pericytes or mixed glial cells, or as a triple-culture with both pericytes and mixed glial cells. The integrity of the BBB models was validated by measures of transendothelial electrical resistance (TEER) and passive permeability to mannitol. The expression of basement membrane proteins was analysed using RT-qPCR, mass spectrometry and immunocytochemistry. Co-culturing mBCECs with pericytes, mixed glial cells, or both significantly increased the TEER compared to the monoculture, and a low passive permeability was correlated with high TEER. The mBCECs expressed all major basement membrane proteins such as laminin-411, laminin-511, collagen [α1(IV)]₂ α2(IV), agrin, perlecan, and nidogen 1 and 2 in vitro. Increased expression of the laminin α5 subunit correlated with the addition of BBB-inducing factors (hydrocortisone, Ro 20-1724, and pCPT-cAMP), whereas increased expression of collagen IV α1 primarily correlated with increased levels of cAMP. In conclusion, BCECs cultured in vitro coherently form a BBB and express basement membrane proteins as a feature of maturation. Cover Image for this issue: doi: 10.1111/jnc.13789.

Stability and Species Specificity of Renal VEGF-A Splicing Patterns in Kidney Disease

Vascular endothelial growth factor A (VEGF-A) is essential for maintaining the glomerular filtration barrier. Absolute renal levels of VEGF-A change in patients with diabetic nephropathy and inflammatory kidney diseases, but whether changes in the renal splicing patterns of VEGF-A play a role remains unclear. In this study, we investigated mRNA splicing patterns of pro-angiogenic isoforms of VEGF-A in glomeruli and whole kidney samples from human patients with kidney disease and from mouse models of kidney disease. Kidney biopsies were obtained from patients with acute rejection following kidney transplantation, patients with diabetic nephropathy, and control subjects. In addition, kidney samples were obtained from mice with lupus nephritis, mice with diabetes mellitus, and control mice. The relative expression of each VEGF-A splice variant was measured using RT-PCR followed by quantitative fragment analysis. The pattern of renal VEGF-A splice variants was unchanged in diabetic nephropathy and lupus nephritis and was stable throughout disease progression in acute transplant rejection and diabetic nephropathy; these results suggest renal VEGF-A splicing stability during kidney disease. The splicing patterns were species-specific; in the control human kidney samples, VEGF-A 121 was the dominant isoform, whereas VEGF-A 164 was the dominant isoform measured in the mouse kidney samples.

The complement factor 5a receptor 1 has a pathogenic role in chronic inflammation and renal fibrosis in a murine model of chronic pyelonephritis

Complement factor 5a (C5a) interaction with its receptor (C5aR1) contributes to the pathogenesis of inflammatory diseases, including acute kidney injury. However, its role in chronic inflammation, particularly in pathogen-associated disorders, is largely unknown. Here we tested whether the development of chronic inflammation and renal fibrosis is dependent on C5aR1 in a murine model of chronic pyelonephritis. C5aR1-deficient (C5aR1-/-) mice showed a significant reduction in bacterial load, tubule injury and tubulointerstitial fibrosis in the kidneys following infection, compared with C5aR1-sufficient mice. This was associated with reduced renal leukocyte infiltration specifically for the population of Ly6Chi proinflammatory monocytes/macrophages and reduced intrarenal gene expression of key proinflammatory and profibrogenic factors in C5aR1-/- mice following infection. Antagonizing C5aR1 decreased renal bacterial load, tissue inflammation and tubulointerstitial fibrosis. Ex vivo and in vitro studies showed that under infection conditions, C5a/C5aR1 interaction upregulated the production of proinflammatory and profibrogenic factors by renal tubular epithelial cells and monocytes/macrophages, whereas the phagocytic function of monocytes/macrophages was down-regulated. Thus, C5aR1-dependent bacterial colonization of the tubular epithelium, C5a/C5aR1-mediated upregulation of local inflammatory responses to uropathogenic E. coli and impairment of phagocytic function of phagocytes contribute to persistent bacterial colonization of the kidney, chronic renal inflammation and subsequent tubulointerstitial fibrosis.

Expression of the High-Affinity Laminin Receptor (67 kDa) in Normal Human Skin and Appendages

The interaction of cells with extracellular matrix components plays a significant role in the regulation of cell biology. Laminin is a large glycoprotein involved in fundamental interactions between cells and the basement membrane. Several cell surface receptors are responsible for cell-matrix interactions. The 67 kDa high affinity laminin receptor, 67LR, is involved in the adhesion of normal cells to the laminin network and is also associated with the metastatic phenotype of some tumoral cells. We have investigated the expression of laminin and of the 67LR in normal human skin using immunoperoxidase staining. Twenty samples of skin were analyzed. Antibody against laminin reacted in a continuous linear band at the dermal-epidermal junction, as well as basement membranes of hair follicles, sebaceous and eccrine sweat glands, and dermal blood vessels. The epidermis and the follicular epithelium were negative for laminin. The 67LR seemed not to be expressed on the basal surface of basal keratinocytes. The major expression of this receptor may be detected in the upper half of the spinous layer and in the granular layer. The cells of the outer root sheath in hair follicle showed the same immunohistochemical pattern described for epidermis. In sebaceous glands and in eccrine sweat glands the secreting epithelium was positive. Endothelial cells of dermal blood vessels were routinely positive for 67LR. We observed that the expression of the 67LR in normal human skin is mostly located in epidermal areas in which the keratinizing process was particularly advanced.

Fabrication and investigation of nanofibrous matrices as esophageal tissue scaffolds using human non-keratinized, stratified, squamous epithelial cells

Clinical conditions of the esophagus are conventionally treated by autologous grafts and are generally associated with complications such as leakage, infection and stenosis necessitating an alternative synthetic graft with superior outcomes.

Potential of Neural Stem Cell-Based Therapy for Parkinson's Disease

Neural stem cell (NSC) transplantation is an emerging strategy for restoring neuronal function in neurological disorders, such as Parkinson's disease (PD), which is characterized by a profound and selective loss of nigrostriatal dopaminergic (DA) neurons. Adult neurogenesis generates newborn neurons that can be observed at specialized niches where endothelial cells (ECs) play a significant role in regulating the behavior of NSCs, including self-renewal and differentiating into all neural lineage cells. In this minireview, we highlight the importance of establishing an appropriate microenvironment at the target site of NSC transplantation, where grafted cells integrate into the surroundings in order to enhance DA neurotransmission. Using a novel model of NSC-EC coculture, it is possible to combine ECs with NSCs, to generate such a neurovascular microenvironment. With appropriate NSCs selected, the composition of the transplant can be investigated through paracrine and juxtacrine signaling within the neurovascular unit (NVU). With target site cellular and acellular compartments of the microenvironment recognized, guided DA differentiation of NSCs can be achieved. As differentiated DA neurons integrate into the existing nigrostriatal DA pathway, the symptoms of PD can potentially be alleviated by reversing characteristic neurodegeneration.

Effect of equine herpesvirus type 1 (EHV-1) infection of nasal mucosa epithelial cells on integrin alpha 6 and on different components of the basement membrane

The respiratory mucosa is the common port of entry of equine herpesvirus type 1 (EHV-1) and several other alphaherpesviruses. An important prerequisite for successful host invasion of the virus is to cross the epithelial cell layer and the underlying basement membrane barrier. In the present study, an analysis was performed to see if an EHV-1 infection of nasal mucosa epithelial cells leads to damage of the underlying extracellular matrix proteins. Nasal mucosa explants were inoculated with EHV-1 and collected at 0, 24 and 48 hours post-inoculation (hpi). Then, double immunofluorescence staining was performed to detect viral-antigen-positive cells on the one hand and integrin alpha 6, laminin, collagen IV and collagen VII on the other hand. The area of these extracellular matrix proteins was measured in regions of interest (ROIs) at a magnification of 200X by means of the software imaging system ImageJ. ROIs were defined beneath uninfected and infected regions. In uninfected regions, 22-28 % of the ROI was stained for integrin alpha 6, 18-37 % for laminin, 14-38 % for collagen IV and 18-26 % for collagen VII. In infected regions, the percentage positive for integrin alpha 6 was significantly decreased to 0.1-9 % and 0.1-6 % after 24 and 48 hours of inoculation, respectively. Infection did not alter the percentages for laminin and collagen IV. For collagen VII, an increase in the percentage (from 18-26 % to 28-39 %) could be observed underneath EHV-1-infected plaques at 48 hours of inoculation. In conclusion, the results revealed a substantial impact of EHV-1 infection on integrin alpha 6 and collagen VII, two important components of the extracellular matrix, which are associated with the basement membrane and may facilitate virus penetration via hijacked leukocytes to underlying tissues.

Targeted drug delivery to the brain using magnetic nanoparticles

Brain capillary endothelial cells denote the blood-brain barrier (BBB), and conjugation of nanoparticles with antibodies that target molecules expressed by these endothelial cells may facilitate their uptake and transport into the brain. Magnetic nanoparticles can be encapsulated in liposomes and carry large molecules with therapeutic potential, for example, siRNA, cDNA and polypeptides. An additional approach to enhance the transport of magnetic nanoparticles across the BBB is the application of extracranially applied magnetic force. Stepwise targeting of magnetic nanoparticles to brain capillary endothelial cells followed by transport through the BBB using magnetic force may prove a novel mechanism for targeted therapy of macromolecules to the brain.

Role of α1 and α2 chains of type IV collagen in early fibrotic lesions of idiopathic interstitial pneumonias and migration of lung fibroblasts

Early fibrotic lesions are thought to be the initial findings of fibrogenesis in idiopathic interstitial pneumonias, but little is known about their properties. Type IV collagen comprises six gene products, α1-α6, and although it is known as a major basement membrane component, its abnormal deposition is seen in fibrotic lesions of certain organs. We studied the expression of type I and III collagen and all α chains of type IV collagen in lung specimens from patients with usual interstitial pneumonia (UIP) or organizing pneumonia (OP) via immunohistochemistry. With cultured lung fibroblasts, we analyzed the expression and function of all α chains of type IV collagen via immunohistochemistry, western blotting, real-time quantitative PCR, and a Boyden chamber migration assay after the knockdown of α1 and α2 chains. Although we observed type I and III collagens in early fibrotic lesions of both UIP and OP, we found type IV collagen, especially α1 and α2 chains, in early fibrotic lesions of UIP but not OP. Fibroblasts enhanced the expression of α1 and α2 chains of type IV collagen after transforming growth factor-β1 stimulation. Small interfering RNA against α1 and α2 chains increased fibroblast migration, with upregulated phosphorylation of focal adhesion kinase (FAK), and adding medium containing fibroblast-produced α1 and α2 chains reduced the increased levels of fibroblast migration and phosphorylation of FAK. Fibroblasts in OP were positive for phosphorylated FAK but fibroblasts in UIP were not. These results suggest that fibroblasts in UIP with type IV collagen deposition, especially α1 and α2 chains, have less ability to migrate from early fibrotic lesions than fibroblasts in OP without type IV collagen deposition. Thus, type IV collagen deposition in early fibrotic lesions of UIP may be implicated in refractory pathophysiology including migration of lesion fibroblasts via a FAK pathway.

Changes of skin collagen orientation associated with chronological aging as probed by polarized-FTIR micro-imaging

During chronological skin aging, alterations in dermal structural proteins cause morphological modifications. Modifications are probably due to collagen fiber (type I collagen) rearrangement and reorientation with aging that have not been researched until now. FTIR microspectroscopy appears as an interesting method to study protein structure under normal and pathological conditions. Associated with a polarizer, this vibrational technique permits us to probe collagen orientation within skin tissue sections, by computing the ratio of integrated intensities of amide I and amide II bands. In this study, we used the polarized-FTIR imaging to evaluate molecular modifications of dermal collagen during chronological aging. The data processing of polarized infrared data revealed that type I collagen fibers become parallel to the skin surface in aged skin dermis. Our approach could find innovative applications in dermatology as well as in cosmetics.

Control of the blood-brain barrier function in cancer cell metastasis

Cerebral metastases are the most common brain neoplasms seen clinically in the adults and comprise more than half of all brain tumours. Actual treatment options for brain metastases that include surgical resection, radiotherapy and chemotherapy are rarely curative, although palliative treatment improves survival and life quality of patients carrying brain-metastatic tumours. Chemotherapy in particular has also shown limited or no activity in brain metastasis of most tumour types. Many chemotherapeutic agents used systemically do not cross the blood-brain barrier (BBB), whereas others may transiently weaken the BBB and allow extravasation of tumour cells from the circulation into the brain parenchyma. Increasing evidence points out that the interaction between the BBB and tumour cells plays a key role for implantation and growth of brain metastases in the central nervous system. The BBB, as the tightest endothelial barrier, prevents both early detection and treatment by creating a privileged microenvironment. Therefore, as observed in several in vivo studies, precise targetting the BBB by a specific transient opening of the structure making it permeable for therapeutic compounds, might potentially help to overcome this difficult clinical problem. Moreover, a better understanding of the molecular features of the BBB, its interrelation with metastatic tumour cells and the elucidation of cellular mechanisms responsible for establishing cerebral metastasis must be clearly outlined in order to promote treatment modalities that particularly involve chemotherapy. This in turn would substantially expand the survival and quality of life of patients with brain metastasis, and potentially increase the remission rate. Therefore, the focus of this review is to summarise the current knowledge on the role and function of the BBB in cancer metastasis.

Reno-protection of G004, a novel anti-diabetic sulfonylurea in db/db mice

1-[4-[2-(4-Bromobenzene-sulfonamino)ethyl]phenylsulfonyl]-3-(trans-4-methylcyclohexyl) urea (G004, CAS865483-06-3) is a synthetic sulfonylurea, incorporating the hypoglycemic active structure of glimepiride (CAS 93479-97-1) and anti-TXA2 receptor (TP) active structure of BM-531(CAS 284464-46-6). In this study, we evaluated the effect of G004 on hyperglycemia and dyslipidemia as well as diabetic nephropathy (DN) in db/db mice by gavage over 90 consecutive days of treatment. The fasting blood glucose (FBG), glucose, and insulin tolerance as well as dyslipidemia were effectively ameliorated in db/db mice treated with G004. Interestingly, renal histological results of db/db mice revealed that G004 markedly reversed the expansion of mesangial extracellular matrix (ECM), the early hallmark of DN. Indeed, G004 treatment downregulated the renal expressions of type 4 collagen (Col IV) and transforming growth factor-β1 (TGF-β1) in db/db mice. In addition, imbalance in expressions of matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor-1 (TIMP-1) in db/db mice kidneys was observed. However, G004 increased and decreased the expressions of MMP-9 and TIMP-1, respectively. It is well known that TGF-β pathway signaling plays an essential role in hyperglycemia-induced cell protein synthesis. On the other hand, MMP/TIMP system is responsible for the breakdown and turnover of ECM. Thus, we speculate that G004 possibly attenuated ECM accumulation via remodeling the synthesis and degradation of ECM component Col IV through modulation in TGF-β1 and MMP-9/TIMP-1 expressions in kidneys of db/db mice. Results from this study provide a strong rationale for G004 to be an efficient glucose-controlling agent with significant reno-protective properties.

MMP-7 and TIMP-1, new targets in predicting poor wound healing in apical periodontitis

INTRODUCTION

Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) are strongly associated with tissue destruction because of inflammation. In this study, we investigated the expression of MMPs and TIMPs messenger RNA and protein levels in apical periodontitis lesions.

METHODS

Tissue samples from patients presenting clinical signs of chronic apical abscess (CAA) or asymptomatic apical periodontitis (AAP) were collected postoperatively and used for gene expression analysis of MMP-2, -3, -7, -9, -14, -16, and -25; TIMP-1; and TIMP-2 in real-time polymerase chain reaction. Immunohistochemistry was also performed to detect the expression of MMP-7 and TIMP-1 proteins. Lastly, U-937 cells were induced to terminal differentiation into macrophages, infected with purified Escherichia coli lipopolysaccharide, and assessed for the expression of MMP-7 and TIMP-1 using immunocytochemistry and confocal microscopy.

RESULTS

Significantly higher messenger RNA levels were found for all genes in AAP and CAA samples when compared with healthy control samples (P < .001). AAP cases exhibited significantly higher TIMP-1 when compared with CAA cases, whereas CAA cases showed higher MMP-2, MMP-7, and MMP-9 messenger RNA levels (P < .05). We also detected positive the expression of MMP-7 and TIMP-1 proteins in the tissue samples. The expression of both MMP-7 and TIMP-1 were increased in lipopolysaccharide-stimulated cells compared with nonstimulated cells and appear to colocalize in the Golgi apparatus.

CONCLUSIONS

MMPs appear to have an influential role in CAA cases in which ongoing tissue destruction is observed. TIMPs are preferentially associated with AAP, perhaps as a subsequent defense mechanism against excessive destruction. Taken together, our findings implicate MMP and TIMP molecules in the dynamics of inflammatory periapical lesion development.

Vitamin a deficiency and alterations in the extracellular matrix

Vitamin A or retinol which is the natural precursor of several biologically active metabolites can be considered the most multifunctional vitamin in mammals. Its deficiency is currently, along with protein malnutrition, the most serious and common nutritional disorder worldwide. It is necessary for normal embryonic development and postnatal tissue homeostasis, and exerts important effects on cell proliferation, differentiation and apoptosis. These actions are produced mainly by regulating the expression of a variety of proteins through transcriptional and non-transcriptional mechanisms. Extracellular matrix proteins are among those whose synthesis is known to be modulated by vitamin A. Retinoic acid, the main biologically active form of vitamin A, influences the expression of collagens, laminins, entactin, fibronectin, elastin and proteoglycans, which are the major components of the extracellular matrix. Consequently, the structure and macromolecular composition of this extracellular compartment is profoundly altered as a result of vitamin A deficiency. As cell behavior, differentiation and apoptosis, and tissue mechanics are influenced by the extracellular matrix, its modifications potentially compromise organ function and may lead to disease. This review focuses on the effects of lack of vitamin A in the extracellular matrix of several organs and discusses possible molecular mechanisms and pathologic implications.

Antenatal exposure of maternal secondhand smoke (SHS) increases fetal lung expression of RAGE and induces RAGE-mediated pulmonary inflammation

Background

Receptors for advanced glycation end-products (RAGE) are immunoglobulin-like pattern recognition receptors abundantly localized to lung epithelium. Our research demonstrated that primary tobacco smoke exposure increases RAGE expression and that RAGE partly mediates pro-inflammatory signaling during exposure. However, the degree to which RAGE influences developing lungs when gestating mice are exposed to secondhand smoke (SHS) has not been determined to date.

Methods

Timed pregnant RAGE null and wild type control mice were exposed to 4 consecutive days of SHS from embryonic day (E) 14.5 through E18.5 using a state of the art nose-only smoke exposure system (Scireq, Montreal, Canada). RAGE expression was assessed using immunofluorescence, immunoblotting, and quantitative RT-PCR. TUNEL immunostaining and blotting for caspase-3 were performed to evaluate effects on cell turnover. Matrix abnormalities were discerned by quantifying collagen IV and MMP-9, a matrix metalloprotease capable of degrading basement membranes. Lastly, TNF-α and IL-1β levels were assessed in order to determine inflammatory status in the developing lung.

Results

Pulmonary RAGE expression was elevated in both dams exposed to SHS and in fetuses gestating within mothers exposed to SHS. Fetal weight, a measure of organismal health, was decreased in SHS-exposed pups, but unchanged in SHS-exposed RAGE null mice. TUNEL assessments suggested a shift toward pulmonary cell apoptosis and matrix in SHS-exposed pups was diminished as revealed by decreased collagen IV and increased MMP-9 expression. Furthermore, SHS-exposed RAGE null mice expressed less TNF-α and IL-1β when compared to SHS-exposed controls.

Conclusions

RAGE augmentation in developing pups exposed to maternal SHS weakens matrix deposition and influences lung inflammation.

Brain morphological defects in prolidase deficient mice: first report

Prolidase gene (PEPD) encodes prolidase enzyme, which is responsible for hydrolysis of dipeptides containing proline or hydroxyproline at their C-terminal end. Mutations in PEPD gene cause, in human, prolidase deficiency (PD), a rare autosomal recessive disorder. PD patients show reduced or absent prolidase activity and a broad spectrum of phenotypic traits including various degrees of mental retardation. This is the first report correlating PD and brain damages using as a model system prolidase deficient mice, the so called dark-like (dal) mutant mice. We focused our attention on dal postnatal brain development, revealing a panel of different morphological defects in the cerebral and cerebellar cortices, such as undulations of the cerebral cortex, cell rarefaction, defects in cerebellar cortex lobulation, and blood vessels overgrowth. These anomalies might be ascribed to altered angiogenic process and loss of pial basement membrane integrity. Further studies will be directed to find a correlation between neuroarchitecture alterations and functional consequences.

Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy.

Enamel organic matrix: potential structural role in enamel and relationship to residual basement membrane constituents at the dentin enamel junction

Although mature enamel is predominantly composed of mineral, a previously uncharacterized organic matrix layer remains in the post-eruptive tissue that begins at the dentin enamel junction and extends 200-300 μm towards the outer tooth surface. Identification of the composition of this layer has been hampered by its insolubility; however, we have developed a single step method to isolate the organic enamel matrix relatively intact. After dissociative dissolution of the matrix with SDS and urea, initial characterization by Western blotting and gel zymography indicates the presence of type IV and type VII basement membrane collagens and active matrix metalloproteinase-20. When combined with data from transgenic knockout mice and from human mutations, these data suggest that the enamel organic matrix (EOM) and dentin enamel junction may have a structural and functional relationship with basement membranes, e.g. skin. To clarify this relationship, we hypothesize a "foundation" model which proposes that components of the EOM form a support structure that stabilizes the crystalline enamel layer, and bonds it to the underlying dentin along the dentin enamel junction. Since we have also co-localized an active matrix metalloproteinase to this layer, our hypothesis suggests that, under pathologic conditions, MMP-mediated degradation of the EOM could destabilize the enamel-dentin interface.

Clinicopathological significance of laminin-5γ2 chain expression in superficial esophageal cancer

The glycoprotein laminin 5γ2 chain (LN-5γ2) has recently become a focus of increased interest and investigation as a marker of invasion in gastrointestinal malignancies. We investigated the significance of LN-5γ2 expression as a prognostic factor in superficial esophageal cancer. The study population consisted of 87 patients who had undergone a transthoracic esophagectomy and three-field lymphadenectomy for the treatment of superficial esophageal cancer at Tokai University Hospital. Formalin-fixed, paraffin-embedded sections of the resected specimens were examined using immunohistochemical staining and hematoxylin and eosin staining to assess the correlations between the LN-5γ2 expression pattern and the clinicopathological factors (age, sex, T-factor, N-factor, ly-factor, v-factor, degree of differentiation, infiltrative growth pattern, tumor node metastasis classification of malignant tumors [TNM] stage, etc.) and the patient outcome. The expression pattern of LN-5γ2 was classified into an extracellular type (E type), characterized by the staining of extracellular matrix such as the basement membrane and the stroma (31 cases, 35.6%), and a cytoplasmic type (C type), characterized by the staining of the cytoplasm in the cancer cells (56 cases, 64.6%). The expression pattern was not correlated with any of the clinicopathological factors that were assessed. However, univariate analyses of the survival analysis data showed that the N-factor (P = 0.011), TNM stage (P = 0.011), and LN-5γ2 C type (P = 0.017) were prognostic factors. A multivariate analysis revealed that the N-factor (P = 0.049) and LN-5γ2 C type (P = 0.048) were prognostic factors. In the survival analysis, a univariate analysis of the 75 T1b cases also showed that the N-factor (P = 0.048), TNM stage (P = 0.048), and LN-5γ2 C type (P = 0.029) were prognostic factors, while a multivariate analysis showed that the LN-5γ2 C type (P = 0.035) was a prognostic factor. The C type expression of LN-5γ2, i.e. confined to the cytoplasm, was correlated with an unfavorable outcome among the patients with superficial esophageal cancer in the present series. Observation of the LN-5γ2 expression pattern may be useful for the diagnosis of highly malignant tumors.

Type VII collagen is enriched in the enamel organic matrix associated with the dentin-enamel junction of mature human teeth

The inner enamel region of erupted teeth is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the residual enamel organic matrix. Since enamel-forming ameloblasts are known to express type VII collagen and type VII collagen null mice display abnormal amelogenesis, the aim of this study was to determine whether type VII collagen is a component of the enamel organic matrix at the dentin-enamel junction (DEJ) of mature human teeth. Immunofluorescent confocal microscopy of demineralized tooth sections localized type VII collagen to the organic matrix surrounding individual enamel rods near the DEJ. Morphologically, immunoreactive type VII collagen helical-bundles resembled the gnarled-pattern of enamel rods detected by Coomassie Blue staining. Western blotting of whole crown or enamel matrix extracts also identified characteristic Mr=280 and 230 kDa type VII dimeric forms, which resolved into 75 and 25 kDa bands upon reduction. As expected, the collagenous domain of type VII collagen was resistant to pepsin digestion, but was susceptible to purified bacterial collagenase. These results demonstrate the inner enamel organic matrix in mature teeth contains macromolecular type VII collagen. Based on its physical association with the DEJ and its well-appreciated capacity to complex with other collagens, we hypothesize that enamel embedded type VII collagen fibrils may contribute not only to the structural resilience of enamel, but may also play a role in bonding enamel to dentin.

Pancreatic cancer counterattack: MUC4 mediates Fas-independent apoptosis of antigen-specific cytotoxic T lymphocyte

Tumor-associated MUC4 mucin has considerable potential as an immunotherapy target for pancreatic cancer. In previous studies, we developed dendritic cell (DC) vaccines which elicited MUC4 antigen-specific cytotoxic T lymphocyte (MS-CTL) response against tumor cells in vitro. Due to the observation that MS-CTL apoptotic rate increased significantly when co-cultured with MUC4+ tumor cells compared with T2 cells, we investigated whether high expression levels of MUC4 in pancreatic cancer cells would have an effect on the significant increase of apoptosis rate of MS-CTLs. First, the adverse influence of regulatory T cells (Tregs) was eliminated by CD8+ T lymphocyte sorting before the induction of MS-CTLs. Then, we constructed clonal MUC4-knockdown HPAC pancreatic cancer sublines with different MUC4 expression for co-incubation system. By utilizing appropriate control to rule out the possible apoptosis-induced pathway of intrinsic activated cell-autonomous death (ACAD) and analogous antigen-dependent apoptosis of CTL (ADAC) in our study system, further analysis of the effect of MUC4 membrane-expression, supernatants and blockade of CTL surface Fas receptor on MS-CTL apoptosis was carried out. The results demonstrated that the level of MUC4 membrane expression strongly positively correlated with MS-CTL apoptosis and the influence of supernatants and Fas-blockade did not significantly correlate with MS-CTL apoptosis. This evidence suggested that there may be a novel counterattack pathway of pancreatic cancer cells, which is a MUC4-mediated, cell contact-dependent and Fas-independent process, to induce CTL apoptosis. Therefore, further exploration and understanding of the potential counterattack mechanisms is beneficial to enhance the efficacy of MUC4 specific tumor vaccines.

Anionic biopolyelectrolytes of the syndecan/perlecan superfamily: physicochemical properties and medical significance

In the review article presented here, we demonstrate that the connective tissue is more than just a matrix for cells and a passive scaffold to provide physical support. The extracellular matrix can be subdivided into proteins (collagen, elastin), glycoconjugates (structural glycoproteins, proteoglycans) and glycosaminoglycans (hyaluronan). Our main focus rests on the anionic biopolyelectrolytes of the perlecan/syndecan superfamily which belongs to extracellular matrix and cell membrane integral proteoglycans. Though the extracellular domain of the syndecans may well be performing a structural role within the extracellular matrix, a key function of this class of membrane intercalated proteoglycans may be to act as signal transducers across the plasma membrane and thus be more appropriately included in the group of cell surface receptors. Nevertheless, there is a continuum in functions of syndecans and perlecans, especially with respect to their structural role and biomedical significance. HS/CS proteoglycans are receptor sites for lipoprotein binding thus intervening directly in lipid metabolism. We could show that among all lipoproteins, HDL has the highest affinity to these proteoglycans and thus instals a feedforward forechecking loop against atherogenic apoB100 lipoprotein deposition on surface membranes and in subendothelial spaces. Therefore, HDL is not only responsible for VLDL/IDL/LDL cholesterol exit but also controls thoroughly the entry. This way, it inhibits arteriosclerotic nanoplaque formation. The ternary complex 'lipoprotein receptor (HS/CS-PG) - lipoprotein (LDL, oxLDL, Lp(a)) - calcium' may be interpreted as arteriosclerotic nanoplaque build-up on the molecular level before any cellular reactivity, possibly representing the arteriosclerotic primary lesion combined with endothelial dysfunction. With laser-based ellipsometry we could demonstrate that nanoplaque formation is a Ca(2+)-driven process. In an in vitro biosensor application of HS-PG coated silica surfaces we tested nanoplaque formation and size in clinical trials with cardiovascular high-risk patients who underwent treatment with ginkgo or fluvastatin. While ginkgo reduced nanoplaque formation (size) by 14.3% (23.4%) in the isolated apoB100 lipid fraction at a normal blood Ca(2+) concentration, the effect of the statin with a reduction of 44.1% (25.4%) was more pronounced. In addition, ginkgo showed beneficial effects on several biomarkers of oxidative stress and inflammation. Besides acting as peripheral lipoprotein binding receptor, HS/CS-PG is crucially implicated in blood flow sensing. A sensor molecule has to fulfil certain mechanochemical and mechanoelectrical requirements. It should possess viscoelastic and cation binding properties capable of undergoing conformational changes caused both mechanically and electrostatically. Moreover, the latter should be ion-specific. Under no-flow conditions, the viscoelastic polyelectrolyte at the endothelium - blood interface assumes a random coil form. Blood flow causes a conformational change from the random coil state to the directed filament structure state. This conformational transition effects a protein unfurling and molecular elongation of the GAG side chains like in a 'stretched' spring. This configuration is therefore combined with an increase in binding sites for Na(+) ions. Counterion migration of Na(+) along the polysaccharide chain is followed by transmembrane Na(+) influx into the endothelial cell and by endothelial cell membrane depolarization. The simultaneous Ca(2+) influx releases NO and PGI2, vasodilatation is the consequence. Decrease in flow reverses the process. Binding of Ca(2+) and/or apoB100 lipoproteins (nanoplaque formation) impairs the flow sensor function. The physicochemical and functional properties of proteoglycans are due to their amphiphilicity and anionic polyelectrolyte character. Thus, they potently interact with cations, albeit in a rather complex manner. Utilizing (23)Na(+) and (39)K(+) NMR techniques, we could show that, both in HS-PG solutions and in native vascular connective tissue, the mode of interaction for monovalent cations is competition. Mg(2+) and Ca(2+) ions, however, induced a conformational change leading to an increased allosteric, cooperative K(+) and Na(+) binding, respectively. Since extracellular matrices and basement membranes form a tight-fitting sheath around the cell membrane of muscle and Schwann cells, in particular around sinus node cells of the heart, and underlie all epithelial and endothelial cell sheets and tubes, a release of cations from or an adsorption to these polyanionic macromolecules can transiently lead to fast and drastic activity changes in these tiny extracellular tissue compartments. The ionic currents underlying pacemaker and action potential of sinus node cells are fundamentally modulated. Therefore, these polyelectrolytic ion binding characteristics directly contribute to and intervene into heart rhythm.

A novel coating of type IV collagen and hyaluronic acid on stent material-titanium for promoting smooth muscle cell contractile phenotype

The method of stent implantation is currently considered an effective means of treating atherosclerosis. However, implanting of cardiovascular stent often leads to intimal breakage and hyperplasia. The phenomenon that vascular smooth muscle cells (SMCs) transform from contractile to synthetic phenotype becomes a serious obstacle to intimal recovery. To improve how SMCs transform from a synthetic to contractile phenotype, a technique of coimmobilization was used to form type IV collagen (CoIV) and hyaluronic acid (HA) coating on the widely used stent material, titanium (Ti). In this work, several bio-functional coatings made of CoIV/HA mixtures in different ratios were fabricated on the Ti surface. The quantitative characterization of CoIV showed that introducing HA could enhance the amount of the immobilized CoIV on the alkali activated Ti (TiOH) surface. The immunofluorescence staining results of myosin heavy chain (MHC) and DAPI showed that the coating of CoIV/HA in ratios of 200 μg/ml (M200) and 500 μg/ml (M500) also could promote SMCs expressing more contractile phenotype compared with TiOH/CoIV control samples, while the AO/PI staining results indicated that SMCs on the M200 and M500 samples showed less apoptosis ratio. Thus, we hope that this study can provide more helpful exploration and application for promoting the SMC contractile phenotype on the cardiovascular stents.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-based nanofibrous scaffolds to support functional esophageal epithelial cells towards engineering the esophagus

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV-gelatin were electrospun to obtain defect-free nanofibers by optimizing various process and solution parameters. Tensile strength, Young's modulus, and wettability of PHBV-gelatin nanofibrous scaffold were determined and compared with PHBV nanofibrous scaffold. Our results demonstrate that PHBV-gelatin nanofibers exhibited higher tensile strength and Young's modulus than the PHBV nanofibers. Human esophageal epithelial cells (HEEpiC) were cultured on PHBV and PHBV-gelatin nanofiber showed better cell proliferation in PHBV nanofibrous scaffold than the PHBV-gelatin scaffold after 7 days of culture. HEEpiC cultured on PHBV and PHBV-gelatin nanofibrous scaffold exhibited characteristic epithelial cobblestone morphology after 3 days of culture. Further, the HEEpiC extracellular matrix (ECM) proteins (collagen type IV and laminin) and phenotypic marker proteins (cytokeratin-4 and 14) expressions were significantly higher in PHBV-gelatin nanofibrous scaffold than the PHBV nanofiber scaffold. However, the long-term stability and functional state of the cells on the PHBV scaffold give it an edge over the blend scaffolds. Thus, PHBV-based nanofibrous scaffolds could be explored further as ECM substitutes for the regeneration of esophageal tissue.