The lung extracellular matrix protein landscape in severe early-onset and moderate chronic obstructive pulmonary disease.

Extracellular matrix (ECM) remodeling has been implicated in the irreversible obstruction of airways and destruction of alveolar tissue in chronic obstructive pulmonary disease (COPD). Studies investigating differences in the lung ECM in COPD have mainly focused on some collagens and elastin, leaving an array of ECM components unexplored. We investigated the differences in the ECM landscape comparing severe-early onset (SEO)-COPD and moderate COPD to control lung tissue for collagen type I α chain 1 (COL1A1), collagen type VI α chain 1 (COL6A1); collagen type VI α chain 2 (COL6A2), collagen type XIV α chain 1 (COL14A1), fibulin 2 and 5 (FBLN2 and FBLN5), latent transforming growth factor ß binding protein 4 (LTBP4), lumican (LUM), versican (VCAN), decorin (DCN), and elastin (ELN) using image analysis and statistical modeling. Percentage area and/or mean intensity of expression of LUM in the parenchyma, and COL1A1, FBLN2, LTBP4, DCN, and VCAN in the airway walls, was proportionally lower in COPD compared to controls. Lowered levels of most ECM proteins were associated with decreasing forced expiratory volume in 1 s (FEV1) measurements, indicating a relationship with disease severity. Furthermore, we identified six unique ECM signatures where LUM and COL6A1 in parenchyma and COL1A1, FBLN5, DCN, and VCAN in airway walls appear essential in reflecting the presence and severity of COPD. These signatures emphasize the need to examine groups of proteins to represent an overall difference in the ECM landscape in COPD that are more likely to be related to functional effects than individual proteins. Our study revealed differences in the lung ECM landscape between control and COPD and between SEO and moderate COPD signifying distinct pathological processes in the different subgroups.NEW & NOTEWORTHY Our study identified chronic obstructive pulmonary disease (COPD)-associated differences in the lung extracellular matrix (ECM) composition. We highlight the compartmental differences in the ECM landscape in different subtypes of COPD. The most prominent differences were observed for severe-early onset COPD. Moreover, we identified unique ECM signatures that describe airway walls and parenchyma providing insight into the intertwined nature and complexity of ECM changes in COPD that together drive ECM remodeling and may contribute to disease pathogenesis.

A comprehensive map of proteoglycan expression and deposition in the pulmonary arterial wall in health and pulmonary hypertension.

Changes in the extracellular matrix of pulmonary arteries (PAs) are a key aspect of vascular remodeling in pulmonary hypertension (PH). Yet, our understanding of the alterations affecting the proteoglycan (PG) family remains limited. We sought to investigate the expression and spatial distribution of major vascular PGs in PAs from healthy individuals and various PH groups (chronic obstructive pulmonary disease: PH-COPD, pulmonary fibrosis: PH-PF, idiopathic: IPAH). PG regulation, deposition, and synthesis were notably heightened in IPAH, followed by PH-PF, with minor alterations in PH-COPD. Single-cell analysis unveiled cell-type and disease-specific PG regulation. Agrin expression, a basement membrane PG, was increased in IPAH, with PA endothelial cells (PAECs) identified as a major source. PA smooth muscle cells (PASMCs) mainly produced large-PGs, aggrecan and versican, and small-leucine-like proteoglycan (SLRP) biglycan, whereas the major PGs produced by adventitial fibroblasts were SLRP decorin and lumican. In IPAH and PF-PH, the neointima-forming PASMC population increased the expression of all investigated large-PGs and SLRPs, except fibroblast-predominant decorin (DCN). Expression of lumican, versican, and biglycan also positively correlated with collagen 1α1/1α2 expression in PASMCs in patients with IPAH and PH-PF. We demonstrated that transforming growth factor-beta (TGF-ß) regulates versican and biglycan expression, indicating their contribution to vessel fibrosis in IPAH and PF-PH. We furthermore show that certain circulating PG levels display a disease-dependent pattern, with increased decorin and lumican across all patient groups, while versican was elevated in PH-COPD and IPAH and biglycan reduced in IPAH. These findings suggest unique compartment-specific PG regulation in different forms of PH, indicating distinct pathological processes.NEW & NOTEWORTHY Idiopathic pulmonary arterial hypertension (IPAH) pulmonary arteries (PAs) displayed the greatest proteoglycan (PG) changes, with PH associated with pulmonary fibrosis (PH-PF) and PH associated with chronic obstructive pulmonary disease (PH-COPD) following. Agrin, an endothelial cell-specific PG, was solely upregulated in IPAH. Among all cells, neo-intima-forming smooth muscle cells (SMCs) displayed the most significant PG increase. Increased levels of circulating decorin, lumican, and versican, mainly derived from SMCs, and adventitial fibroblasts, may serve as systemic indicators of pulmonary remodeling, reflecting perivascular fibrosis and neointima formation.

The endothelial-to-mesenchymal transition changes the focal adhesion site proteins levels and the SLRP-lumican level in HMEC-1 cell line.

Scleroderma, the chronic autoimmune disease is a consequence of inflammation in the connective tissue. Prolonged duration affects formation of compact connective tissue strands (scarring) within the target organ. Endothelial cells undergoing endothelial-to-mesenchymal transition (EndMT) are the source of fibroblast phenotype-resembling cells. EndMT contributes to reorganization of the focal adhesion proteins (FA), including integrins, and intensive extracellular matrix (ECM) remodelling. However, in endothelial cells, the relationship between EndMT and the interaction of integrin receptors with lumican - a component of ECM, is still unclear. Our findings indicate that at the early stages of EndMT caused by Snail-1 transcription factor overexpression, the level of the ß1 integrin subunit and its phosphorylation are elevated. Simultaneously, the changes in the level of proteins that build FAs and promote activation of integrin receptors as well as a decrease in lumican quantity were observed. These modulations contributed to increased migration of human microvascular endothelial cells, HMEC-1. Our findings were achieved by WB, ELISA and wound healing assay. Taken altogether, transfection of HMEC-1 cells with Snail-1 plasmids inducing the early stages of EndMT results in the increase of total FAK and integrin ß1 phosphorylation as well as cell migration: phenomena which are modulated by interaction with lumican.

Matrix lumican endocytosed by immune cells controls receptor ligand trafficking to promote TLR4 and restrict TLR9 in sepsis.

Infections and inflammation are profoundly influenced by the extracellular matrix (ECM), but their molecular underpinnings are ill defined. Here, we demonstrate that lumican, an ECM protein normally associated with collagens, is elevated in sepsis patients' blood, while lumican-null mice resolve polymicrobial sepsis poorly, with reduced bacterial clearance and greater body weight loss. Secreted by activated fibroblasts, lumican promotes Toll-like receptor (TLR) 4 response to bacterial lipopolysaccharides (LPS) but restricts nucleic acid-specific TLR9 in macrophages and dendritic cells. The underlying mechanism involves lumican attachment to the common TLR coreceptor CD14 and caveolin 1 (Cav1) in lipid rafts on immune cell surfaces via two epitopes, which may be cryptic in collagen-associated lumican. The Cav1 binding epitope alone is sufficient for cell surface enrichment of Cav1, while both are required for lumican to increase cell surface TLR4, CD14, and proinflammatory cytokines in response to LPS. Endocytosed lumican colocalizes with TLR4 and LPS and promotes endosomal induction of type I interferons. Lumican-null macrophages show elevated TLR9 in signal-permissive endolysosomes and increased response, while wild types show lumican colocalization with CpG DNA but not TLR9, consistent with a ligand sequestering, restrictive role for lumican in TLR9 signaling. In vitro, lumican competes with CD14 to bind CpG DNA; biglycan, a lumican paralog, also binds CpG DNA and suppresses TLR9 response. Thus, lumican and other ECM proteins, synthesized de novo or released from collagen association during ECM remodeling, may be internalized by immune cells to regulate their transcriptional programs and effector responses that may be harnessed in future therapeutics.

Lumican, a Multifunctional Cell Instructive Biomarker Proteoglycan Has Novel Roles as a Marker of the Hypercoagulative State of Long Covid Disease.

This study has reviewed the many roles of lumican as a biomarker of tissue pathology in health and disease. Lumican is a structure regulatory proteoglycan of collagen-rich tissues, with cell instructive properties through interactions with a number of cell surface receptors in tissue repair, thereby regulating cell proliferation, differentiation, inflammation and the innate and humoral immune systems to combat infection. The exponential increase in publications in the last decade dealing with lumican testify to its role as a pleiotropic biomarker regulatory protein. Recent findings show lumican has novel roles as a biomarker of the hypercoagulative state that occurs in SARS CoV-2 infections; thus, it may also prove useful in the delineation of the complex tissue changes that characterize COVID-19 disease. Lumican may be useful as a prognostic and diagnostic biomarker of long COVID disease and its sequelae.

Differential MMP-14 targeting by biglycan, decorin, fibromodulin, and lumican unraveled by in silico approach.

Small leucine-rich proteoglycans (SLRPs) are major regulators of extracellular matrix assembly and cell signaling. Lumican, a member of the SLRPs family, and its derived peptides were shown to possess antitumor activity by interacting directly with the catalytic domain of MMP-14 leading to the inhibition of its activity. The aim of the present report was to characterize by in silico three-dimensional (3D) modeling the structure and the dynamics of four SLRPs including their core protein and their specific polysaccharide chains to assess their capacity to bind to MMP-14 and to regulate its activity. Molecular docking experiments were performed to identify the specific amino acids of MMP-14 interacting with each of the four SLRPs. The inhibition of each SLRP (100 nM) on MMP-14 activity was measured and the constants of inhibition (Ki) were evaluated. The impact of the number of glycan chains, structures, and dynamics of lumican on the interaction with MMP-14 was assessed by molecular dynamics simulations. Molecular docking analysis showed that all SLRPs bind to MMP-14 through their concave face, but in different regions of the catalytic domain of MMP-14. Each SLRPs inhibited significantly the MMP-14 activity. Finally, molecular dynamics showed the role of glycan chains in interaction with MMP-14 and shielding effect of SLRPs. Altogether, the results demonstrated that each SLRP exhibited inhibition of MMP-14 activity. However, the differential targeting of MMP-14 by the SLRPs was shown to be related not only to the core protein conformation but also to the glycan chain structures and dynamics.

Involvement of small leucine-rich proteoglycans and telocytes in thin and thick human endometrium: immunohistochemical and ultrastructural examination.

Thin endometrium, defined as an endometrial thickness of less than 7 mm during the late follicular phase, is a common cause of frequent cancelation of embryo transfers or recurrent implantation failure during assisted reproductive treatment. Small proteoglycans regulate intracellular signaling cascades by bridging other matrix molecules and tissue elements, affecting cell proliferation, adhesion, migration, and cytokine concentration. The aim of the study is to investigate the role of small leucine-rich proteoglycans in the pathogenesis of thin and thick human endometrium and their differences from normal endometrium in terms of fine structure properties. Normal, thin, and thick endometrial samples were collected, and small leucine-rich proteoglycans (SLRPs), decorin, lumican, biglycan, and fibromodulin immunoreactivities were comparatively analyzed immunohistochemically. The data were compared statistically. Moreover, ultrastructural differences among the groups were evaluated by transmission electron microscopy. The immunoreactivities of decorin, lumican, and biglycan were higher in the thin endometrial glandular epithelium and stroma compared to the normal and thick endometrium (p < .001). Fibromodulin immunoreactivity was also higher in the thin endometrial glandular epithelium than in the normal and thick endometrium (p < .001). However, there was no statistical difference in the stroma among the groups. Ultrastructural features were not profoundly different among cases. Telocytes, however, were not seen in the thin endometrium in contrast to normal and thin endometrial tissues. These findings suggest a possible role of changes in proteoglycan levels in the pathogenesis of thin endometrium.

Three-Dimensional Modeling of CpG DNA Binding with Matrix Lumican Shows Leucine-Rich Repeat Motif Involvement as in TLR9-CpG DNA Interactions.

Lumican is an extracellular matrix proteoglycan known to regulate toll-like receptor (TLR) signaling in innate immune cells. In experimental settings, lumican suppresses TLR9 signaling by binding to and sequestering its synthetic ligand, CpG-DNA, in non-signal permissive endosomes. However, the molecular details of lumican interactions with CpG-DNA are obscure. Here, the 3-D structure of the 22 base-long CpG-DNA (CpG ODN_2395) bound to lumican or TLR9 were modeled using homology modeling and docking methods. Some of the TLR9-CpG ODN_2395 features predicted by our model are consistent with the previously reported TLR9-CpG DNA crystal structure, substantiating our current analysis. Our modeling indicated a smaller buried surface area for lumican-CpG ODN_2395 (1803 Å2) compared to that of TLR9-CpG ODN_2395 (2094 Å2), implying a potentially lower binding strength for lumican and CpG-DNA than TLR9 and CpG-DNA. The docking analysis identified 32 amino acids in lumican LRR1-11 interacting with CpG ODN_2395, primarily through hydrogen bonding, salt-bridges, and hydrophobic interactions. Our study provides molecular insights into lumican and CpG-DNA interactions that may lead to molecular targets for modulating TLR9-mediated inflammation and autoimmunity.

Interplay of Helicobacter pylori, fibroblasts, and cancer cells induces fibroblast activation and serpin E1 expression by cancer cells to promote gastric tumorigenesis.

BACKGROUND: Helicobacter pylori (H. pylori) can disrupt the tight junctions between gastric epithelial cells and penetrate the intercellular spaces acting on epithelial cells, normal fibroblasts (NFs), and cancer-associated fibroblasts (CAFs), but their interaction in gastric cancer tumorigenesis and progression remains unclear. METHODS: Primary CAFs and NFs were isolated from paired gastric cancer tissues and adjacent normal tissues and identified by immunofluorescence staining and western blot analysis for FSP-1, α-SMA, FAP, and vimentin expression. RNA-sequencing was used to compare the transcriptomes between CAFs and NFs. The expressions of FAP, lumican, and α-SMA, human cytokine array, and Transwell assay were used to assess the transformation of NFs to CAFs. CCK-8 assay, colony formation, flow cytometry, Transwell assay, and nude mouse xenograft model were used to determine the effects of Serpin E1 on cell proliferation and metastasis in vitro and in vivo. Finally, Serpin E1 and/or FAP expression was measured in H. pylori-infected gerbil gastric mucosa and human gastric cancer tissues. RESULTS: Gastric CAFs are inflammatory CAFs with α-SMAlowFAPhighlumicanhigh. The interplay of H. pylori, fibroblasts, and cancer cells promotes the transition of NFs to CAFs by inducing cytokine release, especially Serpin E1. Long-term H. pylori infection and CAFs induce Serpin E1 expression in gerbil gastric tissues and human gastric cancer cells. Serpin E1 overexpression enhances the growth, migration, invasion of gastric cancer cells in vitro, and xenograft tumor growth in nude mice via inducing angiogenesis. Serpin E1 and FAP were highly expressed in cancer cells and CAFs of gastric cancer tissues, respectively, and a good correlation was observed between their expression. Higher Serpin E1 expression is negatively associated with the overall survival of patients with gastric cancer. CONCLUSIONS: The interplay of H. pylori, fibroblasts, and cancer cells induced Serpin E1 expression to promote the activation of NFs to CAFs and gastric carcinogenesis. Targeting Serpin E1 will provide a promising therapeutic strategy for gastric cancer by disrupting the interaction between H. pylori, CAFs, and gastric cancer cells.

Lumican is elevated in the lung in human and experimental acute respiratory distress syndrome and promotes early fibrotic responses to lung injury.

BACKGROUND: Fibroproliferative repair starts early in the inflammatory phase of acute respiratory distress syndrome (ARDS) and indicates a poor prognosis. Lumican, a small leucine-rich proteoglycan, is implicated in homeostasis and fibrogenesis, but its role in ARDS is unclear. METHODS: Bronchoalveolar lavage fluid (BALF) samples were obtained from ARDS patients (n = 55) enrolled within 24 h of diagnosis and mechanically ventilated (n = 20) and spontaneously breathing (n = 29) control subjects. Lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse models were intratracheally administered an adeno-associated virus (AAV) vector expressing lumican shRNA. Primary human lung fibroblasts (HLF) and small airway epithelial cells (SAECs) were cultured with tumour necrosis factor (TNF)-α or lumican. Luminex/ELISA, histochemistry/immunohistochemistry, immunofluorescence microscopy, quantitative real-time PCR, and western blotting were performed. RESULTS: Lumican levels were significantly higher in the BALF of ARDS patients than in that of ventilated or spontaneously breathing controls (both p < 0.0001); they were correlated with the PaO2/FiO2 ratio and levels of proinflammatory cytokines (interleukin-6, interleukin-8, and TNF-α) and profibrotic factors (fibronectin, alpha-1 type I collagen [COL1A1], and alpha-1 type III collagen [COL3A1]). Lumican expression was enhanced in the alveolar walls and airway epithelium in the ALI mouse model. Murine lumican levels were also linked to proinflammatory and profibrotic cytokine levels in the BALF. In vitro, TNF-α induced the synthesis and secretion of lumican in HLF. In turn, lumican increased the expression of alpha-smooth muscle actin (α-SMA), COL1A1, and COL3A1 in HLF, upregulated α-SMA and COL3A1, downregulated E-cadherin, and caused spindle-shaped morphological changes in SAECs. Moreover, increased ERK phosphorylation and Slug were noted in both HLF and SAECs treated with lumican. In vivo, AAV-mediated knockdown of lumican inhibited the pulmonary production of fibronectin and COL3A1 and alleviated lung fibrotic lesions in LPS-challenged mice. CONCLUSIONS: Pulmonary lumican levels were increased early in human and experimental ARDS and linked to disease severity and inflammatory fibrotic processes. Lumican triggers the transdifferentiation of lung fibroblasts into myofibroblasts and epithelial-mesenchymal transition in SAECs, possibly via the ERK/Slug pathway. Knockdown of pulmonary lumican attenuated extracellular matrix deposition in ALI mice. Overall, lumican promotes fibrotic responses in the early phase of ARDS, suggesting its potential as a therapeutic target.

Changes in the Brain Extracellular Matrix Composition in schizophrenia: A Pathophysiological Dysregulation and a Potential Therapeutic Target.

The brain extracellular matrix (ECM) is involved in crucial processes of neural support, neuronal and synaptic plasticity, extrasynaptic transmission, and neurotransmission. ECM is a tridimensional fibrillary meshwork composed of macromolecules that determine its bioactivity and give it unique characteristics. The characterization of the brain ECM is critical to understand its dynamic in SZ. Thus, a comparative study was developed with 71 patients with schizophrenia (SZ) and 70 healthy controls. Plasma of participants was analysed by label-free liquid chromatography-tandem mass spectrometry, and the results were validated using the classical western blot method. Lastly, immunostaining of post-mortem human brain tissue was performed to analyse the distribution of the brain ECM proteins by confocal microscopy. The analysis identified four proteins: fibronectin, lumican, nidogen-1, and secreted protein acidic and rich in cysteine (SPARC) as components of the brain ECM. Statistical significance was found for fibronectin (P = 0.0166), SPARC (P = 0.0003), lumican (P = 0.0012), and nidogen-1 (P < 0.0001) that were decreased in the SZ group. Fluorescence imaging of prefrontal cortex (PFC) sections revealed a lower expression of ECM proteins in SZ. Our study proposes a pathophysiological dysregulation of proteins of the brain ECM, whose abnormal composition leads to a progressive neuronal impairment and consequently to neurodegenerative processes due to lack of neurophysiological support and dysregulation of neuronal homeostasis. Moreover, the brain ECM and its components are potential pharmacological targets to develop new therapeutic approaches to treat SZ.

The Anticancer Effect of a Novel Quinoline Derivative 91b1 through Downregulation of Lumican.

Quinoline derivatives have been reported to possess a wide range of pharmaceutical activities. Our group previously synthesized a series of quinoline compounds, in which compound 91b1 showed a significant anticancer effect. The purpose of this study was to evaluate the anticancer activity of compound 91b1 in vitro and in vivo, and screen out its regulated target. A series of cancer cell lines and nontumor cell lines were treated with compound 91b1 by MTS cytotoxicity assay and cell-cycle assay. In vivo anticancer activity was evaluated by a xenografted model on nude mice. Target prediction of 91b1 was assessed by microarray assay and confirmed by pancancer analysis. Relative expression of the target gene Lumican was measured by qRT-PCR. 91b1 significantly reduced tumor size in the nude mice xenograft model. Lumican was downregulated after 91b1 treatment. Lumican was proven to increase tumorigenesis in vivo, as well as cancer cell migration, invasion, and proliferation in vitro. The results of this study suggest that the anticancer activity of compound 91b1 probably works through downregulating the gene Lumican.

Keratocyte Differentiation Is Regulated by NF-κB and TGFß Signaling Crosstalk.

Interleukin-1 (IL-1) and transforming growth factor-beta (TGFß) are important cytokines involved in corneal wound healing. Here, we studied the effect of these cytokines on corneal stromal cell (keratocyte) differentiation. IL-1ß treatment resulted in reduced keratocyte phenotype, as evident by morphological changes and decreased expression of keratocyte markers, including keratocan, lumican, ALDH3A1, and CD34. TGFß1 treatment induced keratocyte differentiation towards the myofibroblast phenotype. This was inhibited by simultaneous treatment with IL-1ß, as seen by inhibition of α-SMA expression, morphological changes, and reduced contractibility. We found that the mechanism of crosstalk between IL-1ß and TGFß1 occurred via regulation of the NF-κB signaling pathway, since the IL-1ß induced inhibition of TGFß1 stimulated keratocyte-myofibroblast differentiation was abolished by a specific NF-κB inhibitor, TPCA-1. We further found that Smad7 participated in the downstream signaling. Smad7 expression level was negatively regulated by IL-1ß and positively regulated by TGFß1. TPCA-1 treatment led to an overall upregulation of Smad7 at mRNA and protein level, suggesting that NF-κB signaling downregulates Smad7 expression levels in keratocytes. All in all, we propose that regulation of cell differentiation from keratocyte to fibroblast, and eventually myofibroblast, is closely related to the opposing effects of IL-1ß and TGFß1, and that the mechanism of this is governed by the crosstalk of NF-κB signaling.

Lumican, an Exerkine, Protects against Skeletal Muscle Loss.

Exerkines are soluble factors secreted by exercised muscles, mimicking the effects of exercise in various organs, including the muscle itself. Lumican is reportedly secreted from muscles; however, its roles in skeletal muscle remain unknown. Herein, we found that lumican mRNA expression in the extensor digitorum longus was significantly higher in exercised mice than in unloading mice, and lumican stimulated myogenesis in vitro. Additionally, lumican knockdown significantly decreased muscle mass and cross-sectional area (CSA) of the muscle fiber in the gastrocnemius muscle of exercised mice. Lumican upregulated phosphorylation of p38 mitogen-activated protein kinase (MAPK) and a p38 inhibitor near completely blocked lumican-stimulated myogenesis. Inhibitors for integrin α2ß1 and integrin ανß3 also prevented lumican-stimulated myogenesis. Systemic lumican treatment, administered via the tail vein for 4 weeks, significantly increased relative muscle masses by 36.1% in ovariectomized mice. In addition, intramuscular lumican injection into unloaded muscles for 2 weeks significantly increased muscle mass by 8.5%. Both intravenous and intramuscular lumican treatment significantly increased muscle CSA. Our in vitro and in vivo experiments indicate that lumican is a muscle-secreted exerkine that affords protection against muscle loss by activating p38 MAPK via integrin receptors.

Epithelial-to-mesenchymal transition and invadopodia markers in breast cancer: Lumican a key regulator.

A great hallmark of breast cancer is the absence or presence of estrogen receptors ERα and ERß, with a dominant role in cell proliferation, differentiation and cancer progression. Both receptors are related with Epithelial-to-Mesenchymal Transition (EMT) since there is a relation between ERs and extracellular matrix (ECM) macromolecules expression, and therefore, cell-cell and cell-ECM interactions. The endocrine resistance of ERα endows epithelial cells with increased aggressiveness and induces cell proliferation, resulting into a mesenchymal phenotype and an EMT status. ERα signaling may affect the transcriptional factors which govern EMT. Knockdown or silencing of ERα and ERß in MCF-7 and MDA-MB-231 breast cancer cells respectively, provoked pivotal changes in phenotype, cellular functions, mRNA and protein levels of EMT markers, and consequently the EMT status. Mesenchymal cells owe their migratory and invasive properties to invadopodia, while in epithelial cells, lamellipodia and filopodia are mostly observed. Invadopodia, are actin-rich protrusions of plasma membrane, promoting proteolytic degradation of ECM and tumor invasion. Cortactin and MMP-14 govern the formation and principal functions of invadopodia. In vitro experiments proved that lumican inhibits cortactin and MMP-14 expression, alters the formation of lamellipodia and transforms mesenchymal cells into epithelial-like. Conclusively, lumican may inhibit or even reverse the several metastatic features that EMT endows in breast cancer cells. Therefore, a lumican-based anti-cancer therapy which will pharmacologically target and inhibit EMT might be interesting to be developed.

Amniotic membrane conditioned medium (AMCM) reduces inflammatory response on human limbal myofibroblast, and the potential role of lumican.

Purpose: Viral infections such as herpetic keratitis (HSK) activate the innate immune response in the cornea triggering opacity and loss of vision. This condition is performed mainly by myofibroblasts that exacerbate secretion of inflammatory cytokines. Amniotic membrane transplantation (AMT) reduces ocular opacity and scarring inhibiting secretion of inflammatory cytokines and proliferation of myofibroblasts. We previously reported that the amniotic membrane (AM) favors an anti-inflammatory microenvironment inhibiting the secretion of inflammatory cytokines, expression of innate immune receptors, and translocation of nuclear NF-κB on human limbal myofibroblasts (HLMs). The aim of the present study was to determine whether the soluble factors of the AM decrease the immune response of HLMs stimulated with polyinosinic-polycytidylic acid sodium salt (poly I:C). Methods: The AM was incubated in Dulbecco's modified eagle medium (DMEM)/F12, and the supernatant was collected to obtain amniotic membrane conditioned medium (AMCM). HLMs were isolated from cadaveric sclera-corneal rims. HLMs were cultured in DMEM/F12 or AMCM and stimulated or not with poly I:C (10 µg/ml) for 12 h to analyze synthesis of CCL2, CCL5, CXCL10, MDA5, RIG-1, and TLR3 or for 2 h to analyze translocation of nuclear NF-kB, IRF3, and IRF7. The proteins contained on AMCM were analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and the acquired peptide ions were analyzed with the Mascot program using both National Center for Biotechnology Information (NCBI) and expressed sequence tag (EST) databases. Results: AMCM downregulated the mRNA levels of CCL2, CCL5, CXCL10, MDA5, RIG-1, and TLR3. In addition, AMCM decreased secretion of CCL2, CCL5, and CXCL10 and translocation of nuclear NF-κB. Interestingly, AMCM increased translocation of nuclear IRF3 and synthesis and secretion of type I IFN-ß. We also identified small leucine-rich proteoglycan lumican in the AMCM. The administration of rh-lumican to poly I:C-stimulated HLMs reduced the mRNA levels of CCL2, CCL5, and CXCL10. Conclusions: These results suggest that the AM can trigger an anti-inflammatory response on HLMs through soluble factors, and that lumican could play an important role in these effects.

Impaired collagen fibril assembly in keloids with enhanced expression of lumican and collagen V.

Keloids are characterized by fibroblast activation and altered architecture of extracellular matrix (ECM). Excessive deposition of ECM molecules and irregular organization of collagen fibers have been observed in keloids. However, the ultrastructural alteration of collagen has not been fully investigated. In this study, the differences in tissue structure, collagen ultrastructure, matrix components, mechanical properties and collagen assembling molecules between keloids and their extra-lesional skins (ELSs) were explored using histology, transmission electron microscope (TEM), qPCR, Western blot, immunohistochemistry and bioinformatics. Histological evaluation showed thinner fibers in keloids with increased contents of collagen III and proteoglycans, which were supported by TEM findings of thinner collagen fibrils and less developed D-band periodicity in keloids than in ELSs (p < 0.05). In addition, total collagen and water contents were significantly increased (p < 0.05) along with richer proteoglycan production in keloids vs ELSs, which also led to increased stiffness and decreased maximal load in keloids compared with ELSs. Mechanism study showed that multiple molecules related to matrix assembly were significantly upregulated in keloids (p < 0.05). In particular, lumican and collagen V showed high degrees in co-expression analysis and their upregulation levels were revealed from microarray data, which were also verified in keloids at both gene and protein levels (p < 0.05). Nevertheless, siRNA knockdown of lumican failed to affect in vitro collagen assembly, but caused upregulated collagen V expression along with the upregulation of focal adhesion kinase, TGF-ß1, TGF-ß3 and PDGF, among which some are known for capable of enhancing collagen V expression. In conclusion, this study demonstrates impaired collagen assembly along with enhanced expression of lumican and collagen V, both are known for interfering with collagen fibril assembly.

Adipose tissue depot-specific intracellular and extracellular cues contributing to insulin resistance in obese individuals.

Adipose tissue dysregulation in obesity strongly influences systemic metabolic homeostasis and is often linked to insulin resistance (IR). However, the molecular mechanisms underlying adipose tissue dysfunction in obesity are not fully understood. Herein, a proteomic analysis of subcutaneous (SC) and omental (OM) fat from lean subjects and obese individuals with different degrees of insulin sensitivity was performed to identify adipose tissue biomarkers related to obesity-associated metabolic disease. Our results suggest that dysregulation of both adipose tissue extracellular matrix (ECM) organization and intracellular trafficking processes may be associated with IR in obesity. Thus, abnormal accumulation of the small leucine-rich proteoglycan, lumican, as observed in SC fat of IR obese individuals, modifies collagen I organization, impairs adipogenesis and activates stress processes [endoplasmic reticulum and oxidative stress] in adipocytes. In OM fat, IR is associated with increased levels of the negative regulator of the Rab family of small GTPases, GDI2, which alters lipid storage in adipocytes by inhibiting insulin-stimulated binding of the Rab protein, Rab18, to lipid droplets. Together, these results indicate that lumican and GDI2 might play depot-dependent, pathogenic roles in obesity-associated IR. Our findings provide novel insights into the differential maladaptive responses of SC and OM adipose tissue linking obesity to IR.

Identification of Lumican and Fibromodulin as Hub Genes Associated with Accumulation of Extracellular Matrix in Diabetic Nephropathy.

INTRODUCTION: Diabetic nephropathy (DN) remains a major cause of end-stage renal disease. The development of novel biomarkers and early diagnosis of DN are of great clinical importance. The goal of this study was to identify hub genes with diagnostic potential for DN by weighted gene co-expression network analysis (WGCNA). METHODS: Gene Expression Omnibus database was searched for microarray data including distinct types of CKD. Gene co-expression network was constructed, and modules specific for DN were identified by WGCNA. Gene ontology (GO) analysis was performed, and the hub genes were screened out within the selected gene modules. In addition, cross-validation was performed in an independent dataset and in samples of renal biopsies with DN and other types of glomerular diseases. RESULTS: Dataset GSE99339 was selected, and a total of 179 microdissected glomeruli samples were analyzed, including DN, normal control, and 7 groups of other glomerular diseases. Twenty-three modules of the total 10,947 genes were grouped by WGCNA, and a module was specifically correlated with DN (r = 0.54, p = 9e-15). GO analysis showed that module genes were mainly enriched in the accumulation of extracellular matrix (ECM). LUM, ELN, FBLN1, MMP2, FBLN5, and FMOD were identified as hub genes. Cross verification showed LUM and FMOD were higher in the DN group and were negatively correlated with estimated glomerular filtration rate (eGFR). In renal biopsies, expression levels of LUM and FMOD were higher in DN than IgA nephropathy, membranous nephropathy, and normal controls. CONCLUSION: By using WGCNA approach, we identified LUM and FMOD related to ECM accumulation and were specific for DN. These 2 genes may represent potential candidate diagnostic biomarkers of DN.

Differential expression of Lumican, Mimecan, Annexin A5 and Serotransferrin in ectopic and matched eutopic endometrium in ovarian endometriosis: a case-control study.

AIM: Endometriosis is a debilitating disease marked by recurrent gynecological proliferations. The present study aimed at performing differential proteomic analysis of matched eutopic and ectopic endometrium from women with ovarian endometriosis. MATERIALS AND METHODS: Proteomes were resolved using nano LC-MS and further identified and quantified using ProteinLynx Global SERVER (PLGS) software. Selected proteins were further chosen for validation by real time-polymerase chain reaction (RT-PCR). RESULTS: The protein profiles uncovered several differentially expressed proteins in the diseased sample (ectopic endometrium) as compared to the reference sample (eutopic endometrium). The study involved an advanced proteomic approach, nano LC-MS, and validates for the first time the upregulation of Mimecan and Lumican proteins in endometriosis. CONCLUSIONS: These proteins may hence prove as potentially useful tools in the search for diagnostic markers for early detection of the disease.