Basement Membrane Fragments Research Articles

Epithelial recurrent erosion dystrophy (ERED) from the splice site altering COL17A1 variant c.3156C>T in families of Finnish-Swedish ancestry.

To describe four Finnish families with epithelial recurrent erosion dystrophy (ERED) caused by the pathogenic variant c.3156C>T in collagen type XVII alpha 1 chain gene (COL17A1). Eleven affected and two unaffected individuals underwent clinical ophthalmological examination, anterior segment photography, and corneal topography. Two of them underwent phototherapeutic keratectomy (PTK). Genetic analysis included both next-generation and Sanger sequencing. Specimens from the manual keratectomy of one patient were available for ophthalmic pathologic examination, including immunohistochemistry. The common splice-site altering synonymous variant c.3156C > T, p.(Gly1052=) in COL17A1 was confirmed in 15 individuals with ERED from the four families. Subepithelial corneal scarring grades varied and increased with age, leading to decreased best-corrected visual acuity. PTK improved vision in 58- and 67-year-old individuals without reactivating the disease. The keratectomy specimens showed an uneven epithelium and a spectrum of basement membrane abnormalities, including breaks, fragmentation, multiplication and entrapment within the subepithelial scar, reflecting recurrent erosions. The stromal cells consisted of varying proportions of bland and activated fibroblasts and myofibroblasts, reflecting different ages of scars. The family with the largest number of known affected generations originated from Southern Sweden. The phenotype in the Finnish ERED families is consistent with earlier reports of the c.3156C > T variant, although the severity has varied between reports. The phenotype may be modulated by other genes. This study suggests a likely founder effect of the variant in both Finnish and Swedish populations due to their shared population histories. If vision is compromised, PTK can be considered especially in older patients.

Basement membrane product, endostatin, as a link between inflammation, coagulation and vascular permeability in COVID-19 and non-COVID-19 acute respiratory distress syndrome.

Immune cell recruitment, endothelial cell barrier disruption, and platelet activation are hallmarks of lung injuries caused by COVID-19 or other insults which can result in acute respiratory distress syndrome (ARDS). Basement membrane (BM) disruption is commonly observed in ARDS, however, the role of newly generated bioactive BM fragments is mostly unknown. Here, we investigate the role of endostatin, a fragment of the BM protein collagen XVIIIα1, on ARDS associated cellular functions such as neutrophil recruitment, endothelial cell barrier integrity, and platelet aggregation in vitro. In our study we analyzed endostatin in plasma and post-mortem lung specimens of patients with COVID-19 and non-COVID-19 ARDS. Functionally, we investigated the effect of endostatin on neutrophil activation and migration, platelet aggregation, and endothelial barrier function in vitro. Additionally, we performed correlation analysis for endostatin and other critical plasma parameters. We observed increased plasma levels of endostatin in our COVID-19 and non-COVID-19 ARDS cohort. Immunohistochemical staining of ARDS lung sections depicted BM disruption, alongside immunoreactivity for endostatin in proximity to immune cells, endothelial cells, and fibrinous clots. Functionally, endostatin enhanced the activity of neutrophils, and platelets, and the thrombin-induced microvascular barrier disruption. Finally, we showed a positive correlation of endostatin with soluble disease markers VE-Cadherin, c-reactive protein (CRP), fibrinogen, and interleukin (IL)-6 in our COVID-19 cohort. The cumulative effects of endostatin on propagating neutrophil chemotaxis, platelet aggregation, and endothelial cell barrier disruption may suggest endostatin as a link between those cellular events in ARDS pathology.

Histopathology unveiling the structural damage in gonads of Catla catla due to freshwater contamination

Potentially harmful materials, e.g., heavy metals, pesticides, dyes, and hydrocarbons, are often released untreated into freshwater bodies. When such pollutants are released in large quantities, there may be large-scale, sudden mortalities of aquatic organisms. This study summarizes experimental evidence about the disruption of gonadal development due to freshwater contamination. Adult fish specimens of Catla catla were collected from the River Chenab downstream of the Chakbandi Main Drain (CMD) entrance into the Chenab River. CMD collects domestic and industrial sewage wastes from Faisalabad city and disposes them into River Chenab, polluting this water body. Water samples were analyzed from each site of fish harvest for water quality parameters. Collected fish specimens were subjected to histopathological evaluation to detect the impact of pollution on the gonads of this fish species. The male Catla catla gonads showed marked histopathological alterations such as testes degeneration, generalized tissue degeneration produced by fragmentation and detachment of basement membrane, necrosis, and fibrosis in the testis. A loss of tubular arrangement, rupturing of the blood vessels, delimiting seminiferous lobules, vascular hypertrophy of the interstitial compartment, and appearance of a clustered organization were observed. The follicular epithelium in vitellogenic oocytes, rupturing and detachment of follicular basement membrane tissue with cytoplasmic vacuolization, immature oocytes with scattered yolk droplets, hypertrophied follicular epithelium, interstitial proteinaceous fluid deposition, and structural deterioration of follicles with early oocytes were observed in the ovary.

Translocation of pro-apoptotic proteins through basements membrane and hemidesmosome in the corneal epithelium of the keratoconus subjects

Keratoconus (KC) is an ectatic corneal disorder to frequently characterize by corneal thinning and severe visual impairment, and it continues to be one of the leading indications for corneal transplantation. The etiology is multi-factorial and pathological changes have been observed in the KC corneas. It is still unknown where the disease originates, but the changes in the corneal epithelium are considered to start even before a clinical sign appears. The present study, we investigated the potential role of basement membrane and hemidesmosomes damage whether they are participating a key role on pro-apoptotic protein elevations in the KC corneal epithelium. Samples of corneal epithelium from three KC and three normal subjects were used by Western blot, electron microscopy, immunohistochemistry and fluorescent staining. The histology and ultrastructural changes in the KC corneal sections were illustrated that arises the damage to the bowmen's layer, hemidesmosomes, and basement membrane broken. The basal cells of the corneal epithelium in KC exhibits squamous cells with absence of nuclei compared to the corneal epithelium of normal subjects. The expression of pro-apoptotic proteins Bax, phospho-p53, and cleaved caspase-3 were elevated significantly in the KC cornea when compared to normal corneal tissues extracts. Similarly, immunohistochemistry and triple antibodies staining (Bax, phosphor-p53, and cleaved caspase-3) of KC subjects were demonstrated an identical result as compared to the normal corneal sections. The Nile red/DAPI stain results correspondingly illustrated that KC corneas had less membrane lipid contents, and occurs a fewer progenitor cells than peripheral corneas in the normal subjects. Hence, the collective results indicate the colocalization of pro-apoptotic proteins transduced through basal epithelial cell damage and fragmented basement membrane, which is boost apoptotic induction in the KC corneal epithelium.

Anatomical Parameters of Eye and Associated Histological Features are Potential Risk Factors for Development of Pterygium

<p><strong>Background and Objectives:</strong> Pterygium occurs throughout the world but the exact pathogenesis is still not clear. The reports on the association between eye anatomical parameters and presence of pterygium is controversial, similarly how the histological features of the pterygium may differ due to these parameters is not known. Thus, the focus of this study was to explore this gap by assessing and comparing the anatomical parameters of eye in pterygium patients and in healthy controls. In addition, histological features of pterygium were assessed and correlated with the eye anatomical parameters of the patients.</p>
 <p><strong>Methods:</strong> Forty-one pterygium patients of age range 25-70 years undergoing surgery were included in the study after taking written informed consent. Forty-two age and sex matched healthy controls were also recruited for assessing anatomical eye parameters. Relevant history with demographic details of every subject was obtained. All participants underwent a thorough ophthalmic examination. Assessment of orbital protrusion and interpalpebral distance was measured by millimeter scale. Tear film breakup time (TFBUT) and Schirmer test was used for tear film assessment. Presence of any meibomian gland dysfunction (MGD) was examined by slit lamp. Post-surgical tissue samples from patients were assessed for histological features with H& E, PAS & Verhoeff stains. Data were processed and analyzed by using SPSS version 21.0.</p>
 <p><strong>Results: </strong>Eyeball protrusion and MGD was found higher in pterygium patients as compared to controls. Basement membrane fragmentation on histology significantly correlated with the eyeball protrusion (P<0.04) and TFBUT (P<0.020), inflammation significantly correlated with the MGD (P<0.05) while elastosis showed significant correlation with TFBUT (P<0.001).</p>
 <p><strong>Conclusion:</strong> It can be concluded that eye anatomical parameters might be the risk factors in the development of pterygium. The correlation between certain histological features & eye anatomical parameters indicate that anatomical eye parameters can be taken as risk factor for recurrence in these patients. </p>

Peripheral Nerve Sheath Tumors Resembling Human Atypical Neurofibroma in Goldfish (Carassius auratus, Linnaeus, 1758).

Simple SummaryIn animals, especially in fish, dermal neoplasms are a common finding. A distinction between peripheral nerve sheath tumors (PNSTs) and other spindle cell tumors (SCTs) is not always possible when relying exclusively on routine cytological and histopathological findings. The current study aims to determine a minimal subset of stains required to correctly identify PNSTs in goldfish and describes, in detail, six dermal nodules that resemble atypical neurofibroma in humans. Interestingly, muscular and fibroblastic tumors were excluded using Azan trichrome staining, while Alcian blue and Gomori’s reticulin stains revealed the presence of intratumoral areas of mucins and basement membrane fragments, respectively. In addition, PAS and PAS with diastase pretreatment confirmed the latter finding and revealed intra- and extracellular glycogen granules. Immunohistochemistry displayed reactivity for S100 protein, CNPase, and phosphorylated and non-phosphorylated neurofilament-positive axons. Altogether, these findings suggested that Azan trichrome staining, Gomori’s reticulin staining, and immunohistochemistry for S100 protein and CNPase represent a useful set of stains to identify and characterize PNSTs in goldfish.Skin spindle cell tumors (SSTs) frequently occur in fishes, with peripheral nerve sheath tumors (PNSTs) being the most commonly reported neoplasms in goldfish. However, distinguishing PNSTs from other SCTs is not always possible when relying exclusively on routine cytological and histopathological findings. Therefore, the aim of this study is to characterize six skin nodules, resembling atypical neurofibromas in humans, found in six cohabiting goldfish (Carassius auratus), and to determine a minimal subset of special stains required to correctly identify PNSTs in this species. Routine cytology and histopathology were indicative of an SCT with nuclear atypia in all cases, with randomly distributed areas of hypercellularity and loss of neurofibroma architecture. Muscular and fibroblastic tumors were excluded using Azan trichrome staining. Alcian blue and Gomori’s reticulin stains revealed the presence of intratumoral areas of glycosaminoglycans or mucins and basement membrane fragments, respectively. PAS and PAS–diastase stains confirmed the latter finding and revealed intra- and extracellular glycogen granules. Immunohistochemistry displayed multifocal, randomly distributed aggregates of neoplastic cells positive for S100 protein and CNPase, intermingled with phosphorylated and non-phosphorylated neurofilament-positive axons. Collectively, these findings are consistent with a PNST resembling atypical neurofibroma in humans, an entity not previously reported in goldfish, and suggest that Azan trichrome staining, reticulin staining, and immunohistochemistry for S100 protein and CNPase represent a useful set of special stains to identify and characterize PNSTs in this species.

Correlation between sestrin2 expression and airway remodeling in COPD

BackgroundAirway remodeling is a major pathological characteristic of chronic obstructive pulmonary disease (COPD), and has been shown to be associated with oxidative stress. Sestrin2 has recently drawn attention as an important antioxidant protein. However, the underlying correlation between sestrin2 and airway remodeling in COPD has yet to be clarified.MethodsA total of 124 subjects were enrolled in this study, including 62 control subjects and 62 COPD patients. The pathological changes in airway tissues were assessed by different staining methods. The expression of sestrin2 and matrix metalloproteinase 9 (MMP9) in airway tissues was monitored by immunohistochemistry. Enzyme-linked immunosorbent assays (ELISAs) were used to detect the serum concentrations of sestrin2 and MMP9. The airway parameters on computed tomography (CT) from all participants were measured for evaluating airway remodeling. The relationship between serum sestrin2 and MMP9 concentration and airway parameters in chest CT was also analyzed.ResultsIn patients with COPD, staining of airway structures showed distinct pathological changes of remodeling, including cilia cluttered, subepithelial fibrosis, and reticular basement membrane (Rbm) fragmentation. Compared with control subjects, the expression of sestrin2 and MMP9 was significantly increased in both human airway tissues and serum. Typical imaging characteristics of airway remodeling and increased airway parameters were also found by chest CT. Additionally, serum sestrin2 concentration was positively correlated with serum MMP9 concentration and airway parameters in chest CT.ConclusionIncreased expression of sestrin2 is related to airway remodeling in COPD. We demonstrated for the first time that sestrin2 may be a novel biomarker for airway remodeling in patients with COPD.

Histopathological and Histomorphometric studies on the effects of Olanzapine on Testis: An experimental study in Albino Rats

Introduction: Toxic effects of an antipsychotic drug on male gonad were explored experimentally. Olanzapine, an antipsychotic drug, has affinity for a wide range of receptors posing danger to the large variety of organs. Since olanzapine can bind to these receptors, a direct effect of these drugs on spermatogenesis is possible. Therefore testis, an organ least attended, has been selected in the present study. Material and Methods: Two groups of animals of the equal number were designed in such a way that the first group acted as control and second group acted as experimental. After histopathological comparison in the tissue of the testis, histomorphometric analysis was also performed to support the former. Twelve albino male rats were divided into two groups of six animals each. Olanzapine was injected in experimental rats in a dose of 4 mg/kg body weight intraperitoneally for 6 weeks. Sections of both experimental and control testis were examined under light microscope for histopathological findings. Histomorphometric informations were also collected to support the former findings by using ocular and stage micrometers. Student's t-test was used to compare the control testis findings with the single variable experimental one. Results: Experimental testis showed intra and interlobular edema, compressed seminiferous tubules, thinning and fragmentation of basement membrane. Spermatogenic cells were smudgy and compressed by edema fluid. Blood vessels showed inflammatory cells in the lumen. Discussion and Conclusion: Olanzapine-induced testicular degeneration might lead to reduced libido, a fact of great social impact.

Circulating Vascular Basement Membrane Fragments are Associated with the Diameter of the Abdominal Aorta and Their Expression Pattern is Altered in AAA Tissue

Abdominal aortic aneurysm (AAA) is characterised by enhanced proteolytic activity, and extracellular matrix (ECM) remodelling in the vascular wall. Type IV and XVIII collagen/endostatin are structural proteins in vascular basement membrane (VBM), a specialised ECM structure. Here the association between plasma levels of these collagens with the aortic diameter and expansion rate is studied, and their expression in aortic tissue characterised. This was a retrospective population based cohort study. Type IV and XVIII collagen/endostatin were analysed in plasma by ELISA assay in 615 men, divided into three groups based on the aortic diameter: 1) normal aorta ≤ 25mm, 2) sub-aneurysmal aorta (SAA) 26-29mm, and 3) AAA≥30mm. Follow up data were available for 159 men. The association between collagen levels and aortic diameter at baseline, and with the expansion rate at follow up were analysed in ordinal logistic regression and linear regression models, controlling for common confounding factors. Tissue expression of the collagens was analysed in normal aorta (n=6) and AAA (n=6) by immunofluorescence. Plasma levels of type XVIII collagen/endostatin (136ng/mL [SD 29] in individuals with a normal aorta diameter, 154ng/ml [SD 45] in SAA, and 162ng/ml [SD 46] in AAA; p=.001) and type IV collagen (105ng/mL [SD 42] normal aorta, 124ng/ml [SD 46] SAA, and 127ng/ml [SD 47] AAA; p=.037) were associated with a larger aortic diameter. A significant association was found between the baseline levels of type XVIII/endostatin and the aortic expansion rate (p=.035), but in the multivariable model, only the initial aortic diameter remained significantly associated with expansion (p=.005). Altered expression patterns of both collagens were observed in AAA tissue. Plasma levels of circulating type IV and XVIII collagen/endostatin increase with AAA diameter. The expression pattern of VBM proteins is altered in the aneurysm wall.

Renal Interstitial Lipid Accumulation in Cats with Chronic Kidney Disease

Chronic kidney disease (CKD) is a common progressive condition described in dogs and cats, involving several non-specific morphological and histological lesions. Recently, renal interstitial lipid accumulation was reported in cats with CKD; however, to date, little is known about this condition and its pathogenesis. The aim of this study was to investigate the occurrence and to characterize renal interstitial lipid deposits in dogs and cats. A total of 49 animals (27 cats and 22 dogs) with CKD were included in the study. Interstitial lipid accumulation was found exclusively in cats, affecting both males and females. In 55.6% of the cases, the extent of the lesion was not equally distributed in right and left kidneys. The lesion was always found in the cortical region, associated with an inflammatory reaction. Lipid macrovacuoles were also observed in the tubular epithelium, as well as in areas of tubulorrhexis. The amount of lipid deposited was variable, being more extensive in older animals. Data from this study suggest that interstitial lipid accumulation may be related to tubular lipidosis (typical of feline kidneys) associated with epithelial degeneration and lysis, and to tubular basement membrane fragmentation. Extended studies on this condition are necessary, as it appears to be involved in the progression of CKD and may, therefore, have repercussion in the clinical management of the disease and in the development of new approaches to delay its advance.

Building discontinuous liver sinusoidal vessels.

Blood vessels have a unified mission to circulate blood throughout the body; however, they have additional diverse and specialized roles in various organs. For example, in the liver, discontinuous sinusoids, which are fenestrated capillaries with intercellular gaps and a fragmented basement membrane, facilitate delivery of macromolecules to highly metabolic hepatocytes. During embryonic development, discontinuous sinusoids also allow circulating hematopoietic progenitor and stem cells to populate the liver and promote blood cell differentiation. In this issue of the JCI, Géraud et al. describe an essential role for the transcription factor GATA4 in promoting the development of discontinuous sinusoids. In the absence of liver sinusoidal GATA4, mouse embryos developed hepatic capillaries with upregulated endothelial cell junction proteins and a continuous basement membrane. These features prevented hematopoietic progenitor cells from transmigrating into the developing liver, and Gata4-mutant embryos died from subsequent liver hypoplasia and anemia. This study highlights the surprising and extensive transcriptional control GATA4 exercises over specialized liver vascular development and function.

Topical Administration of Acylated Homoserine Lactone Improves Epithelialization of Cutaneous Wounds in Hyperglycaemic Rats.

Clinicians often experience delayed epithelialization in diabetic patients, for which a high glucose condition is one of the causes. However, the mechanisms underlying delayed wound closure have not been fully elucidated, and effective treatments to enhance epithelialization in patients with hyperglycaemia have not been established. Here we propose a new reagent, acylated homoserine lactone (AHL), to improve the delayed epithelialization due to the disordered formation of a basement membrane of epidermis in hyperglycaemic rats. Acute hyperglycaemia was induced by streptozotocin injection in this experiment. Full thickness wounds were created on the flanks of hyperglycaemic or control rats. Histochemical and immunohistochemical analyses were performed to identify hyperglycaemia-specific abnormalities in epidermal regeneration by comparison between groups. We then examined the effects of AHL on delayed epithelialization in hyperglycaemic rats. Histological analysis showed the significantly shorter epithelializing tissue (P < 0.05), abnormal structure of basement membrane (fragmentation and immaturity), and hypo- and hyperproliferation of basal keratinocytes in hyperglycaemic rats. Treating the wound with AHL resulted in the decreased abnormalities of basement membrane, normal distribution of proliferating epidermal keratinocytes, and significantly promoted epithelialization (P < 0.05) in hyperglycemic rats, suggesting the improving effects of AHL on abnormal epithelialization due to hyperglycemia.

Perlecan antagonizes collagen IV and ADAMTS9/GON-1 in restricting the growth of presynaptic boutons.

In the mature nervous system, a significant fraction of synapses are structurally stable over a long time scale. However, the mechanisms that restrict synaptic growth within a confined region are poorly understood. Here, we identified that in the C. elegans neuromuscular junction, collagens Type IV and XVIII, and the secreted metalloprotease ADAMTS/GON-1 are critical for growth restriction of presynaptic boutons. Without these components, ectopic boutons progressively invade into the nonsynaptic region. Perlecan/UNC-52 promotes the growth of ectopic boutons and functions antagonistically to collagen Type IV and GON-1 but not to collagen XVIII. The growth constraint of presynaptic boutons correlates with the integrity of the extracellular matrix basal lamina or basement membrane (BM), which surrounds chemical synapses. Fragmented BM appears in the region where ectopic boutons emerge. Further removal of UNC-52 improves the BM integrity and the tight association between BM and presynaptic boutons. Together, our results unravel the complex role of the BM in restricting the growth of presynaptic boutons and reveal the antagonistic function of perlecan on Type IV collagen and ADAMTS protein.

ZO-1 and ZO-2 are required for extra-embryonic endoderm integrity, primitive ectoderm survival and normal cavitation in embryoid bodies derived from mouse embryonic stem cells.

The Zonula Occludens proteins ZO-1 and ZO-2 are cell-cell junction-associated adaptor proteins that are essential for the structural and regulatory functions of tight junctions in epithelial cells and their absence leads to early embryonic lethality in mouse models. Here, we use the embryoid body, an in vitro peri-implantation mouse embryogenesis model, to elucidate and dissect the roles ZO-1 and ZO-2 play in epithelial morphogenesis and de novo tight junction assembly. Through the generation of individual or combined ZO-1 and ZO-2 null embryoid bodies, we show that their dual deletion prevents tight junction formation, resulting in the disorganization and compromised barrier function of embryoid body epithelial layers. The disorganization is associated with poor microvilli development, fragmented basement membrane deposition and impaired cavity formation, all of which are key epithelial tissue morphogenetic processes. Expression of Podocalyxin, which positively regulates the formation of microvilli and the apical membrane, is repressed in embryoid bodies lacking both ZO-1 and ZO-2 and this correlates with an aberrant submembranous localization of Ezrin. The null embryoid bodies thus give an insight into how the two ZO proteins influence early mouse embryogenesis and possible mechanisms underlying the embryonic lethal phenotype.

A randomized controlled trial of inhaled corticosteroids (ICS) on markers of epithelial&amp;ndash;mesenchymal transition (EMT) in large airway samples in COPD: an exploratory proof of concept study

BackgroundWe recently reported that epithelial–mesenchymal transition (EMT) is active in the airways in chronic obstructive pulmonary disease (COPD), suggesting presence of an active profibrotic and promalignant stroma. With no data available on potential treatment effects, we undertook a blinded analysis of inhaled corticosteroids (ICS) effects versus placebo on EMT markers in previously obtained endobronchial biopsies in COPD patients, as a “proof of concept” study.MethodsAssessment of the effects of inhaled fluticasone propionate (FP; 500 μg twice daily for 6 months) versus placebo in 34 COPD patients (23 on fluticasone propionate and eleven on placebo). The end points were epidermal growth factor receptor (EGFR; marker of epithelial activation) and the biomarkers of EMT: reticular basement membrane (Rbm) fragmentation (“hallmark” structural marker), matrix metalloproteinase-9 (MMP-9) cell expression, and S100A4 expression in basal epithelial and Rbm cells (mesenchymal transition markers).ResultsEpithelial activation, “clefts/fragmentation” in the Rbm, and changes in the other biomarkers all regressed on ICS, at or close to conventional levels of statistical significance. From these data, we have been able to nominate primary and secondary end points and develop power calculations that would be applicable to a definitive prospective study.ConclusionAlthough only a pilot “proof of concept” study, this trial provided strong suggestive support for an anti-EMT effect of ICS in COPD airways. A larger and fully powered prospective study is now indicated as this issue is likely to be extremely important. Such studies may clarify the links between ICS use and better clinical outcomes and protection against lung cancer in COPD.

FGF and Notch signaling hierarchy in sensory neurogenesis (651.18)

The purpose of this study was to determine the regulatory relationship of sensory neurogenesis in the trigeminal placode between the Fibroblast Growth Factor (FGF) and Notch signaling pathways. To do this, FGF signaling was blocked cell autonomously or globally while simultaneously downregulating Notch signaling in 10‐12 somite stage Gallus gallus chick embryos. Cell autonomous FGF inhibition with global Notch downregulation significantly reduced the number of proneural cells contributing the future trigeminal ganglion (p=0.0002). A similar reduction was found with concurrent global inhibition of FGF and Notch (p&lt;0.0001). Remarkably, blocking FGF either cell autonomously or globally with simultaneous Notch downregulation reversed the effects of robust neurogenesis seen with Notch downregulation alone (p&lt;0.0001). Further, Notch downregulation for 4 or 12 hours showed no difference in the level of FGF‐receptor 4 mRNA expression when compared to controls. It did however result in a highly fragmented basal lamina, which was reversed when blocking FGF signaling. From these data, we invalidate the FGF downregulates Notch in sensory neurogenesis model and propose a mechanism for parallel regulation of FGF and Notch leading to basement membrane fragmentation and subsequent delamination of differentiating opV placode cells.Grant Funding Source: Supported by NIH/NICHD ‐ R01 HD046475

486 Prenatal Allergen Exposure Facilitated Airway Remodeling by Airborne Allergen Stimuli in Postnatal Life

BackgroundMurine asthma models are mainly created through adulthood sensitization, but lack airway remodeling hallmarks.AimsThis study aimed to examine airway remodeling in the prenatally-sensitized murine asthma model.MethodsFVB/N fetuses were exposed to...

Tumour basement membrane laminin expression predicts outcome following curative resection of pancreatic head cancer

Background:Although widely fragmented BMs have been associated with adverse outcome in several cancer types, comparatively little is known with respect to its effect on the prognosis of pancreatic cancer. The aim of the current study was therefore to determine the prognostic value of tumour basement membrane (BM) continuity in two anatomically closely related, however, prognostically different tumours, pancreatic head- and periampullary cancer.Methods:Tumour BM continuity was determined by immunohistochemical staining of its two major components, laminin and collagen type IV. Associations were made with recurrence free survival (RFS), cancer-specific survival (CSS), overall survival (OS) and conventional prognostic factors.Results:Fifty-nine and 61% of pancreatic head and periampullary tumours, respectively, showed limited BM laminin expression. Whereas 43% and 41% of pancreatic head and periampullary cancers, respectively, showed limited BM collagen type IV expression. Limited BM laminin was associated with poor outcome following curative resection of pancreatic head cancer (P=0.034, 0.013 and 0.017 for RFS, CSS and OS, respectively). Two and a half times as many patients with ⩾25% BM laminin were recurrence free and alive 5 years following resection compared with those with limited BM laminin. Although staining patterns of both BM components were weakly correlated with each other, BM collagen type IV expression was not significantly associated with outcome in either tumour type.Conclusion:Discontinuous BMs, determined by laminin expression, are associated with poor outcome following curative resection of pancreatic head cancer.

COL4A2 mutation associated with familial porencephaly and small-vessel disease

Familial porencephaly, leukoencephalopathy and small-vessel disease belong to the spectrum of disorders ascribed to dominant mutations in the gene encoding for type IV collagen alpha-1 (COL4A1). Mice harbouring mutations in either Col4a1 or Col4a2 suffer from porencephaly, hydrocephalus, cerebral and ocular bleeding and developmental defects. We observed porencephaly and white matter lesions in members from two families that lack COL4A1 mutations. We hypothesized that COL4A2 mutations confer genetic predisposition to porencephaly, therefore we sequenced COL4A2 in the family members and characterized clinical, neuroradiological and biochemical phenotypes. Genomic sequencing of COL4A2 identified the heterozygous missense G1389R in exon 44 in one family and the c.3206delC change in exon 34 leading to frame shift and premature stop, in the second family. Fragmentation and duplication of epidermal basement membranes were observed by electron microscopy in a c.3206delC patient skin biopsy, consistent with abnormal collagen IV network. Collagen chain accumulation and endoplasmic reticulum (ER) stress have been proposed as cellular mechanism in COL4A1 mutations. In COL4A2 (3206delC) fibroblasts we detected increased rates of apoptosis and no signs of ER stress. Mutation phenotypes varied, including porencephaly, white matter lesions, cerebellar and optic nerve hypoplasia and unruptured carotid aneurysm. In the second family however, we found evidence for additional factors contributing to the phenotype. We conclude that dominant COL4A2 mutations are a novel major risk factor for familial cerebrovascular disease, including porencephaly and small-vessel disease with reduced penetrance and variable phenotype, which might also be modified by other contributing factors.

Tumor suppressor function of Liver kinase B1 (Lkb1) is linked to regulation of epithelial integrity

Although loss of epithelial integrity is a hallmark of advanced cancer, it remains poorly understood whether genetic alterations corrupting this integrity causally facilitate tumorigenesis. We show that conditional deletion of tumor suppressor gene Lkb1 (Par-4) in the mammary gland compromises epithelial integrity manifested by mislocalization of cell polarity markers, lateralization of tight junctions, deterioration of desmosomes and basement membrane (BM), and hyperbranching of the mammary ductal tree. We identify the desmosomal BM remodelling serine protease Hepsin as a key factor mediating Lkb1 loss-induced structural alterations in mammary epithelium and BM fragmentation. Although loss of Lkb1 alone does not promote mammary tumorigenesis, combination of Lkb1 deficiency with oncogenic c-Myc leads to dramatic acceleration in tumor formation. The results coupling Lkb1 loss-mediated epithelial integrity defects to mislocalization of serine protease Hepsin and to oncogenic synergy with c-Myc imply that Lkb1 loss facilitates oncogenic proliferation by releasing epithelial cells from structural BM boundaries.