Interaction between periostin and BMP-1 promotes proteolytic activation of lysyl oxidase

Mapping the Periostin splice isoforms in atopic dermatitis and an in vitro asthma model - A multi-platform analysis using mass spectrometry and RT-qPCR

Periostin is a matricellular protein known to be alternatively spliced to produce ten isoforms with a molecular weight of 78-91 kDa. Within the extracellular matrix, periostin attaches to cell surfaces to induce signaling via integrin-binding and actively participates in fibrillogenesis, orchestrating the arrangement of collagen in the extracellular environment. In atopic diseases such as atopic dermatitis (AD) and asthma, periostin is known to participate in driving the disease-causing type 2 inflammation. The periostin isoforms expressed in these diseases and the implication of the alternative splicing events are unknown. Here, we present two universal assays to map the expression of periostin isoforms at the mRNA (RT-qPCR) and protein (PRM-based mass spectrometry) levels. We use these assays to study the splicing profile of periostin in AD lesions as well as in in vitro models of AD and asthma. In these conditions, periostin displayed overexpression with isoforms 3 and 5 standing out as highly overexpressed. Notably, isoforms 9 and 10 exhibited a divergent pattern relative to the remaining isoforms. Isoforms 9 and 10 are often overlooked in periostin research and this paper presents the first evidence of their expression at the protein level. This underlines the necessity to include isoforms 9 and 10 in future research addressing periostin splice isoforms. The assays presented in this paper hold the potential to improve our insight into the splicing profile of periostin in tissues and diseases of interest. The application of these assays to AD lesions and in vitro models demonstrated their potential for identifying isoforms of particular significance, warranting a further in-depth investigation.

Development of a top-down MS assay for specific identification of human periostin isoforms

Periostin is a matricellular protein encoded by the POSTN gene that is alternatively spliced to produce ten different periostin isoforms with molecular weights ranging from 78 to 91 kDa. It is known to promote fibrillogenesis, organize the extracellular matrix, and bind integrin-receptors to induce cell signaling. As well as being a key component of the wound healing process, it is also known to participate in the pathogenesis of different diseases including atopic dermatitis, asthma, and cancer. In both health and disease, the functions of the different periostin isoforms are largely unknown. The ability to precisely determine the isoform profile of a given human sample is fundamental for characterizing their functional significance. Identification of periostin isoforms is most often carried out at the transcriptional level using RT-PCR based approaches, but due to high sequence homogeneity, identification on the protein level has always been challenging. Top-down proteomics, where whole proteins are measured by mass spectrometry, offers a fast and reliable method for isoform identification. Here we present a fully developed top-down mass spectrometry assay for the characterization of periostin splice isoforms at the protein level.

Periostin regulates lysyl oxidase through ERK1/2 MAPK-dependent serum response factor in activated cardiac fibroblasts

Collagen crosslinking, mediated by lysyl oxidase, is an adaptive mechanism of the cardiac repair process initiated by cardiac fibroblasts postmyocardial injury. However, excessive crosslinking leads to cardiac wall stiffening, which impairs the contractile properties of the left ventricle and leads to heart failure. In this study, we investigated the role of periostin, a matricellular protein, in the regulation of lysyl oxidase in cardiac fibroblasts in response to angiotensin II and TGFβ1. Our results indicated that periostin silencing abolished the angiotensin II and TGFβ1-mediated upregulation of lysyl oxidase. Furthermore, the attenuation of periostin expression resulted in a notable reduction in the activity of lysyl oxidase. Downstream of periostin, ERK1/2 MAPK signaling was found to be activated, which in turn transcriptionally upregulates the serum response factor to facilitate the enhanced expression of lysyl oxidase. The periostin-lysyl oxidase association was also positively correlated in an in vivo rat model of myocardial infarction. The expression of periostin and lysyl oxidase was upregulated in the collagen-rich fibrotic scar tissue of the left ventricle. Remarkably, echocardiography data showed a reduction in the left ventricular wall movement, ejection fraction, and fractional shortening, indicative of enhanced stiffening of the cardiac wall. These findings shed light on the mechanistic role of periostin in the collagen crosslinking initiated by activated cardiac fibroblasts. Our findings signify periostin as a possible therapeutic target to reduce excessive collagen crosslinking that contributes to the structural remodeling associated with heart failure.

Targeted Antisense Oligonucleotide-Mediated Skipping of Murine Postn Exon 17 Partially Addresses Fibrosis in D2.mdx Mice

Periostin, a multifunctional 90 kDa protein, plays a pivotal role in the pathogenesis of fibrosis across various tissues, including skeletal muscle. It operates within the transforming growth factor beta 1 (Tgf-β1) signalling pathway and is upregulated in fibrotic tissue. Alternative splicing of Periostin's C-terminal region leads to six protein-coding isoforms. This study aimed to elucidate the contribution of the isoforms containing the amino acids encoded by exon 17 (e17+ Periostin) to skeletal muscle fibrosis and investigate the therapeutic potential of manipulating exon 17 splicing. We identified distinct structural differences between e17+ Periostin isoforms, affecting their interaction with key fibrotic proteins, including Tgf-β1 and integrin alpha V. In vitro mouse fibroblast experimentation confirmed the TGF-β1-induced upregulation of e17+ Periostin mRNA, mitigated by an antisense approach that induces the skipping of exon 17 of the Postn gene. Subsequent in vivo studies in the D2.mdx mouse model of Duchenne muscular dystrophy (DMD) demonstrated that our antisense treatment effectively reduced e17+ Periostin mRNA expression, which coincided with reduced full-length Periostin protein expression and collagen accumulation. The grip strength of the treated mice was rescued to the wild-type level. These results suggest a pivotal role of e17+ Periostin isoforms in the fibrotic pathology of skeletal muscle and highlight the potential of targeted exon skipping strategies as a promising therapeutic approach for mitigating fibrosis-associated complications.

Identification of gravity-responsive serum proteins in spaceflight mice using a quantitative proteomic approach with data-independent acquisition mass spectrometry

Physical inactivity associated with gravity unloading, such as microgravity during spaceflight and hindlimb unloading (HU), can cause various physiological changes. In this study, we attempted to identify serum proteins whose levels fluctuated in response to gravity unloading. First, we quantitatively assessed changes in the serum proteome profiles of spaceflight mice using mass spectrometry with data-independent acquisition. The serum levels of several proteins involved in the responses to estrogen and glucocorticoid, blood vessel maturation, osteoblast differentiation, and ossification were changed by microgravity exposure. Furthermore, a collective evaluation of serum proteomic data from spaceflight and HU mice identified 30 serum proteins, including Mmp2, Igfbp2, Tnc, Cdh5, and Pmel, whose levels varied to a similar extent in both gravity unloading models. These changes in serum levels could be involved in the physiological changes induced by gravity unloading. A collective evaluation of serum, femur, and soleus muscle proteome data of spaceflight mice also showed 24 serum proteins, including Igfbp5, Igfbp3, and Postn, whose levels could be associated with biological changes induced by microgravity. This study examined serum proteome profiles in response to gravity unloading, and may help deepen our understanding of microgravity adaptation mechanisms during prolonged spaceflight missions.

Periostin/Bone Morphogenetic Protein 1 axis axis regulates proliferation and osteogenic differentiation of sutured mesenchymal stem cells and affects coronal suture closure in the TWIST1+/- mouse model of craniosynostosis

BACKGROUND AND OBJECTIVE

The pathogenesis of coronal suture craniosynostosis is often attributed to the dysregulated cellular dynamics, particularly the excessive proliferation and abnormal osteogenic differentiation of suture cells. Despite its clinical significance, the molecular mechanims of this condition remain inadequately understood. This study is dedicated to exploring the influence of the Periostin/Bone Morphogenetic Protein 1 (BMP1) axis on the growth and osteogenic maturation of Suture Mesenchymal Stem Cells (SMSCs), which are pivotal in suture homeostasis.

METHODS

Neonatal TWIST Basic Helix-Loop-Helix Transcription Factor 1 heterozygous (TWIST1+/-) mice, aged one day, were subjected to adenoviral vector-mediated Periostin upregulation. To modulate Periostin/BMP1 levels in SMSCs, we employed siRNA and pcDNA 3.1 vectors. Histological and molecular characterizations, including hematoxylin and eosin staining, Western blot, and immunohistochemistry were employed to study suture closure phenotypes and protein expression patterns. Cellular assays, encompassing colony formation, 5-ethynyl-2'deoxyuridine, and wound healing tests were conducted to analyze SMSC proliferation and migration. Osteogenic differentiation was quantified using Alkaline Phosphatase (ALP) and Alizarin Red S (ARS) staining, while protein markers of proliferation and differentiation were evaluated by Western blotting. The direct interaction between Periostin and BMP1 was validated through co-immunoprecipitation assays.

RESULTS

In the TWIST1+/- model, an upregulation of Periostin coupled with a downregulation of BMP1 was observed. Augmenting Periostin expression mitigated craniosynostosis. In vitro, overexpression of Periostin or BMP1 knockdown suppressed SMSC proliferation, migration, and osteogenic differentiation. Periostin knockdown manifested an inverse biological impact. Notably, the suppressive influence of Periostin overexpression on SMSCs was effectively counteracted by upregulating BMP1. There was a direct interaction between Periostin and BMP1.

CONCLUSION

These findings underscore the significance of the Periostin/BMP1 axis in regulating craniosynostosis and SMSC functions, providing new insights into the molecular mechanisms of craniosynostosis and potential targets for therapeutic intervention.

Runx2 heterozygosity alters homeostasis of the periodontal complex

BACKGROUND AND OBJECTIVE

Haploinsufficiency of Runx2 (Runx2+/- ) causes dental anomalies. However, little is known about the involvement of Runx2 in the maintenance of dentin, cementum, and the periodontal ligament (PDL) during adulthood. This study aimed to observe the effects of Runx2+/- on homeostasis of the periodontal complex.

MATERIALS AND METHODS

A total of 14 three-month-old Runx2+/- mice and their wild-type littermates were examined using micro-computed tomography, histology, and immunohistochemistry. Phenotypic alterations in the dentin, cementum, and PDL were characterized and quantified.

RESULTS

Haploinsufficiency of Runx2 caused cellular changes in the PDL space including reduction of cell proliferation and apoptosis, and irregular attachment of the collagen fibers in the PDL space into the cementum. Absence of continuous thickness of cementum was also observed in Runx2+/- mice.

CONCLUSION

Runx2 is critical for cementum integrity and attachment of periodontal fibers. Because of its importance to cementum homeostasis, Runx2 is essential for homeostasis of periodontal complex.

Identification of Hypoxia Prognostic Signature in Glioblastoma Multiforme Based on Bulk and Single-Cell RNA-Seq

Glioblastoma (GBM) represents a profoundly aggressive and heterogeneous brain neoplasm linked to a bleak prognosis. Hypoxia, a common feature in GBM, has been linked to tumor progression and therapy resistance. In this study, we aimed to identify hypoxia-related differentially expressed genes (DEGs) and construct a prognostic signature for GBM patients using multi-omics analysis. Patient cohorts were collected from publicly available databases, including the Gene Expression Omnibus (GEO), the Chinese Glioma Genome Atlas (CGGA), and The Cancer Genome Atlas-Glioblastoma Multiforme (TCGA-GBM), to facilitate a comprehensive analysis. Hypoxia-related genes (HRGs) were obtained from the Molecular Signatures Database (MSigDB). Differential expression analysis revealed 41 hypoxia-related DEGs in GBM patients. A consensus clustering approach, utilizing these DEGs' expression patterns, identified four distinct clusters, with cluster 1 showing significantly better overall survival. Machine learning techniques, including univariate Cox regression and LASSO regression, delineated a prognostic signature comprising six genes (ANXA1, CALD1, CP, IGFBP2, IGFBP5, and LOX). Multivariate Cox regression analysis substantiated the prognostic significance of a set of three optimal signature genes (CP, IGFBP2, and LOX). Using the hypoxia-related prognostic signature, patients were classified into high- and low-risk categories. Survival analysis demonstrated that the high-risk group exhibited inferior overall survival rates in comparison to the low-risk group. The prognostic signature showed good predictive performance, as indicated by the area under the curve (AUC) values for one-, three-, and five-year overall survival. Furthermore, functional enrichment analysis of the DEGs identified biological processes and pathways associated with hypoxia, providing insights into the underlying mechanisms of GBM. Delving into the tumor immune microenvironment, our analysis revealed correlations relating the hypoxia-related prognostic signature to the infiltration of immune cells in GBM. Overall, our study highlights the potential of a hypoxia-related prognostic signature as a valuable resource for forecasting the survival outcome of GBM patients. The multi-omics approach integrating bulk sequencing, single-cell analysis, and immune microenvironment assessment enhances our understanding of the intricate biology characterizing GBM, thereby potentially informing the tailored design of therapeutic interventions.

Expression of the Pro-Fibrotic Marker Periostin in a Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is characterised by fibrotic tissue deposition in skeletal muscle. We assessed the role of periostin in fibrosis using mdx mice, an established DMD murine model, for which we conducted a thorough examination of periostin expression over a year. RNA and protein levels in diaphragm (DIA) muscles were assessed and complemented by a detailed histological analysis at 5 months of age. In dystrophic DIAs, periostin (Postn) mRNA expression significantly exceeded that seen in wildtype controls at all timepoints analysed, with the highest expression at 5 months of age (p < 0.05). We found Postn to be more consistently highly expressed at the earlier timepoints compared to established markers of fibrosis like transforming growth factor-beta 1 (Tgf-β1) and connective tissue growth factor (Ctgf). Immunohistochemistry confirmed a significantly higher periostin protein expression in 5-month-old mdx mice compared to age-matched healthy controls (p < 0.01), coinciding with a significant fibrotic area percentage (p < 0.0001). RT-qPCR also indicated an elevated expression of Tgf-β1, Col1α1 (collagen type 1 alpha 1) and Ctgf in mdx DIAs compared to wild type controls (p < 0.05) at 8- and 12-month timepoints. Accordingly, immunoblot quantification demonstrated elevated periostin (3, 5 and 8 months, p < 0.01) and Tgf-β1 (8 and 12 months, p < 0.001) proteins in the mdx muscle. These findings collectively suggest that periostin expression is a valuable marker of fibrosis in this relevant model of DMD. They also suggest periostin as a potential contributor to fibrosis development, with an early onset of expression, thereby offering the potential for timely therapeutic intervention and its use as a biomarker in muscular dystrophies.

Emerging Role of Non-collagenous Bone Proteins as Osteokines in Extraosseous Tissues

Bone is a unique tissue, composed of various types of cells embedded in a calcified extracellular matrix (ECM), whose dynamic structure consists of organic and inorganic compounds produced by bone cells. The main inorganic component is represented by hydroxyapatite, whilst the organic ECM is primarily made up of type I collagen and non-collagenous proteins. These proteins play an important role in bone homeostasis, calcium regulation, and maintenance of the hematopoietic niche. Recent advances in bone biology have highlighted the importance of specific bone proteins, named "osteokines", possessing endocrine functions and exerting effects on nonosseous tissues. Accordingly, osteokines have been found to act as growth factors, cell receptors, and adhesion molecules, thus modifying the view of bone from a static tissue fulfilling mobility to an endocrine organ itself. Since bone is involved in a paracrine and endocrine cross-talk with other tissues, a better understanding of bone secretome and the systemic roles of osteokines is expected to provide benefits in multiple topics: such as identification of novel biomarkers and the development of new therapeutic strategies. The present review discusses in detail the known osseous and extraosseous effects of these proteins and the possible respective clinical and therapeutic significance.

The role of periostin in cardiac fibrosis

Cardiac fibrosis, which is the buildup of proteins in the connective tissues of the heart, can lead to end-stage extracellular matrix (ECM) remodeling and ultimately heart failure. Cardiac remodeling involves changes in gene expression in cardiac cells and ECM, which significantly leads to the morbidity and mortality in heart failure. However, despite extensive research, the elusive intricacies underlying cardiac fibrosis remain unidentified. Periostin, an extracellular matrix (ECM) protein of the fasciclin superfamily, acts as a scaffold for building complex architectures in the ECM, which improves intermolecular interactions and augments the mechanical properties of connective tissues. Recent research has shown that periostin not only contributes to normal ECM homeostasis in a healthy heart but also serves as a potent inducible regulator of cellular reorganization in cardiac fibrosis. Here, we reviewed the constitutive domain of periostin and its interaction with other ECM proteins. We have also discussed the critical pathophysiological functions of periostin in cardiac remodeling mechanisms, including two distinct yet potentially intertwined mechanisms. Furthermore, we will focus on the intrinsic complexities within periostin research, particularly surrounding the contentious issues observed in experimental findings.

The molecular mechanism underlying dermatomyositis related interstitial lung disease: evidence from bioinformatic analysis and in vivo validation

Background

Dermatomyositis (DM) is an autoimmune and inflammatory disease that can affect the lungs, causing interstitial lung diseases (ILD). However, the exact pathophysiological mechanisms underlying DM-ILD are unknown. Idiopathic pulmonary fibrosis (IPF) belongs to the broader spectrum of ILD and evidence shows that common pathologic pathways might lie between IPF and DM-ILD.

Methods

We retrieved gene expression profiles of DM and IPF from the Gene Expression Omnibus (GEO) and utilized weighted gene co-expression network analysis (WGCNA) to reveal their co-expression modules. We then performed a differentially expressed gene (DEG) analysis to identify common DEGs. Enrichment analyses were employed to uncover the hidden biological pathways. Additionally, we conducted protein-protein interaction (PPI) networks analysis, cluster analysis, and successfully found the hub genes, whose levels were further validated in DM-ILD patients. We also examined the relationship between hub genes and immune cell abundance in DM and IPF. Finally, we conducted a common transcription factors (TFs)-genes network by NetworkAnalyst.

Results

WGCNA revealed 258 intersecting genes, while DEG analysis identified 66 shared genes in DM and IPF. All of these genes were closely related to extracellular matrix and structure, cell-substrate adhesion, and collagen metabolism. Four hub genes (POSTN, THBS2, COL6A1, and LOXL1) were derived through intersecting the top 30 genes of the WGCNA and DEG sets. They were validated as active transcripts and showed diagnostic values for DM and IPF. However, ssGSEA revealed distinct infiltration patterns in DM and IPF. These four genes all showed a positive correlation with immune cells abundance in DM, but not in IPF. Finally, we identified one possible key transcription factor, MYC, that interact with all four hub genes.

Conclusion

Through bioinformatics analysis, we identified common hub genes and shared molecular pathways underlying DM and IPF, which provides valuable insights into the intricate mechanisms of these diseases and offers potential targets for diagnostic and therapeutic interventions.

Periostin C-Terminal Is Intrinsically Disordered and Interacts with 143 Proteins in an In Vitro Epidermal Model of Atopic Dermatitis

Human periostin is a 78-91 kDa matricellular protein implicated in extracellular matrix remodeling, tumor development, metastasis, and inflammatory diseases like atopic dermatitis, psoriasis, and asthma. The protein consists of six domains, including an N-terminal Cys-rich CROPT domain, four fasciclin-1 domains, and a C-terminal domain. The exons encoding the C-terminal domain may be alternatively spliced by shuffling four exons, generating ten variants of unknown function. Here, we investigate the structure and interactome of the full-length variant of the C-terminal domain with no exons spliced out. The structural analysis showed that the C-terminal domain lacked a tertiary structure and was intrinsically disordered. In addition, we show that the motif responsible for heparin-binding is in the conserved very C-terminal part of periostin. Pull-down confirmed three known interaction partners and identified an additional 140 proteins, among which nine previously have been implicated in atopic dermatitis. Based on our findings, we suggest that the C-terminal domain of periostin facilitates interactions between connective tissue components in concert with the four fasciclin domains.

Recombinant lysyl oxidase effects on embryonic tendon cell phenotype and behavior

Lysyl oxidase (LOX) plays an important role in the elaboration of tendon mechanical properties during embryonic development by mediating enzymatic collagen crosslinking. We previously showed recombinant LOX (rLOX) treatment of developing tendon significantly increased LOX-mediated collagen crosslink density to enhance tendon mechanical properties at different stages of tissue formation. Working toward the future development of rLOX-based therapeutic strategies to enhance mechanical properties of tendons that are compromised, such as after injury or due to abnormal development, this study characterized the direct effects of rLOX treatment on embryonic tendon cells from different stages of tissue formation. Tendon cell morphology, proliferation rate, proliferative capacity, and metabolic activity were not affected by rLOX treatment. Tenogenic phenotype was stable with rLOX treatment, reflected by no change in cell morphology or tendon marker messenger RNA (mRNA) levels assessed by reverse-transcription polymerase chain reaction. Collagen mRNA levels also remained constant. Matrix metalloproteinase-9 expression levels were downregulated in later stage tendon cells, but not in earlier stage cells, whereas enzyme activity levels were undetected. Bone morphogenetic protein-1 (BMP-1) expression was upregulated in earlier stage tendon cells, but not in later stage cells. Furthermore, BMP-1 activity was unchanged when intracellular LOX enzyme activity levels were upregulated in both stage cells, suggesting exogenous rLOX may have entered the cells. Based on our data, rLOX treatment had minimal effects on tendon cell phenotype and behaviors. These findings will inform future development of LOX-focused treatments to enhance tendon mechanical properties without adverse effects on tendon cell phenotype and behaviors.

Carcinoma-associated fibroblast-derived lysyl oxidase-rich extracellular vesicles mediate collagen crosslinking and promote epithelial-mesenchymal transition via p-FAK/p-paxillin/YAP signaling

Carcinoma-associated fibroblasts (CAFs) are the main cellular components of the tumor microenvironment and promote cancer progression by modifying the extracellular matrix (ECM). The tumor-associated ECM is characterized by collagen crosslinking catalyzed by lysyl oxidase (LOX). Small extracellular vesicles (sEVs) mediate cell-cell communication. However, the interactions between sEVs and the ECM remain unclear. Here, we demonstrated that sEVs released from oral squamous cell carcinoma (OSCC)-derived CAFs induce collagen crosslinking, thereby promoting epithelial-mesenchymal transition (EMT). CAF sEVs preferably bound to the ECM rather than being taken up by fibroblasts and induced collagen crosslinking, and a LOX inhibitor or blocking antibody suppressed this effect. Active LOX (αLOX), but not the LOX precursor, was enriched in CAF sEVs and interacted with periostin, fibronectin, and bone morphogenetic protein-1 on the surface of sEVs. CAF sEV-associated integrin α2β1 mediated the binding of CAF sEVs to collagen I, and blocking integrin α2β1 inhibited collagen crosslinking by interfering with CAF sEV binding to collagen I. CAF sEV-induced collagen crosslinking promoted the EMT of OSCC through FAK/paxillin/YAP pathway. Taken together, these findings reveal a novel role of CAF sEVs in tumor ECM remodeling, suggesting a critical mechanism for CAF-induced EMT of cancer cells.

Peptide location fingerprinting identifies structural alterations within basement membrane components in ageing kidney

During ageing, the glomerular and tubular basement membranes (BM) of the kidney undergo a progressive decline in function that is underpinned by histological changes, including glomerulosclerosis and tubular interstitial fibrosis and atrophy. This BM-specific ageing is thought to result from damage accumulation to long-lived extracellular matrix (ECM) protein structures. Determining which BM proteins are susceptible to these structure-associated changes, and the possible mechanisms and downstream consequences, is critical to understand age-related kidney degeneration and to identify markers for therapeutic intervention. Peptide location fingerprinting (PLF) is an emerging proteomic mass spectrometry analysis technique capable of identifying ECM proteins with structure-associated differences that may occur by damage modifications in ageing. Here, we apply PLF as a bioinformatic screening tool to identify BM proteins with structure-associated differences between young and aged human glomerular and tubulointerstitial compartments. Several functional regions within key BM components displayed alterations in tryptic peptide yield, reflecting potential age-dependent shifts in molecular (e.g. laminin-binding regions in agrin) and cellular (e.g. integrin-binding regions in laminins 521 and 511) interactions, oxidation (e.g. collagen IV) and the fragmentation and release of matrikines (e.g. canstatin and endostatin from collagens IV and XVIII). Furthermore, we found that periostin and the collagen IV α2 chain exhibited structure-associated differences in ageing that were conserved between human kidney and previously analysed mouse lung, revealing BM components that harbour shared susceptibilities across species and organs.

Focusing on the Native Matrix Proteins in Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS) is a widespread valvular heart disease affecting people in aging societies, primarily characterized by fibrosis, inflammation, and progressive calcification, leading to valve orifice stenosis. Understanding the factors associated with CAVS onset and progression is crucial to develop effective future pharmaceutical therapies. In CAVS, native extracellular matrix proteins modifications, play a significant role in calcification in vitro and in vivo. This work aimed to review the evidence on the alterations of structural native extracellular matrix proteins involved in calcification development during CAVS and highlight its link to deregulated biomechanical function.

Multiple Roles of LOXL2 in the Progression of Hepatocellular Carcinoma and Its Potential for Therapeutic Targeting

LOXL2, a copper-dependent amine oxidase, has emerged as a promising therapeutic target in hepatocellular carcinoma (HCC). Increased LOXL2 expression in HCC has been linked with an aggressive phenotype and represents a poor prognostic factor. Here, we focus on the mechanisms through which LOXL2 orchestrates multiple oncogenic functions in HCC development. We performed a review of the current knowledge on the roles LOXL2 performs in the modulation of the HCC tumor microenvironment, formation of premetastatic niches, and epithelial-mesenchymal transition. We also highlighted the complex interplay between LOXL2 and hypoxia, angiogenesis, and vasculogenic mimicry in HCC. At the end of the review, we summarize the current LOXL2 inhibitors and discuss their potential in HCC precision treatment.

Periostin+ Stromal Cells Guide Lymphovascular Invasion by Cancer Cells

Cancer cell dissemination to sentinel lymph nodes is associated with poor patient outcomes, particularly in breast cancer. The process by which cancer cells egress from the primary tumor upon interfacing with the lymphatic vasculature is complex and driven by dynamic interactions between cancer cells and stromal cells, including cancer-associated fibroblasts (CAF). The matricellular protein periostin can distinguish CAF subtypes in breast cancer and is associated with increased desmoplasia and disease recurrence in patients. However, as periostin is secreted, periostin-expressing CAFs are difficult to characterize in situ, limiting our understanding of their specific contribution to cancer progression. Here, we used in vivo genetic labeling and ablation to lineage trace periostin+ cells and characterize their functions during tumor growth and metastasis. Periostin-expressing CAFs were spatially found at periductal and perivascular margins, were enriched at lymphatic vessel peripheries, and were differentially activated by highly metastatic cancer cells versus poorly metastatic counterparts. Surprisingly, genetically depleting periostin+ CAFs slightly accelerated primary tumor growth but impaired intratumoral collagen organization and inhibited lymphatic, but not lung, metastases. Periostin ablation in CAFs impaired their ability to deposit aligned collagen matrices and inhibited cancer cell invasion through collagen and across lymphatic endothelial cell monolayers. Thus, highly metastatic cancer cells mobilize periostin-expressing CAFs in the primary tumor site that promote collagen remodeling and collective cell invasion within lymphatic vessels and ultimately to sentinel lymph nodes.

SIGNIFICANCE

Highly metastatic breast cancer cells activate a population of periostin-expressing CAFs that remodel the extracellular matrix to promote escape of cancer cells into lymphatic vessels and drive colonization of proximal lymph nodes.

Establishing in vivo and ex vivo chick embryo models to investigate fetal tendon healing

Injured adult tendons heal fibrotically and possess high re-injury rates, whereas fetal tendons appear to heal scarlessly. However, knowledge of fetal tendon wound healing is limited due in part to the need for an accessible animal model. Here, we developed and characterized an in vivo and ex vivo chick embryo tendon model to study fetal tendon healing. In both models, injury sites filled rapidly with cells and extracellular matrix during healing, with wound closure occurring faster in vivo. Tendons injured at an earlier embryonic stage improved mechanical properties to levels similar to non-injured controls, whereas tendons injured at a later embryonic stage did not. Expression levels of tendon phenotype markers, collagens, collagen crosslinking regulators, matrix metalloproteinases, and pro-inflammatory mediators exhibited embryonic stage-dependent trends during healing. Apoptosis occurred during healing, but ex vivo tendons exhibited higher levels of apoptosis than tendons in vivo. Future studies will use these in vivo and ex vivo chick embryo tendon injury models to elucidate mechanisms of stage-specific fetal tendon healing to inform the development of therapeutic approaches to regeneratively heal adult tendons.

Involvement of lysyl oxidase in the pathogenesis of arterial stiffness in chronic kidney disease

Patients with chronic kidney disease (CKD) are at increased risk for adverse cardiovascular events. CKD is associated with increases in arterial stiffness, whereas improvements in arterial stiffness correlate with better survival. However, arterial stiffness is increased early in CKD, suggesting that there might be additional factors, unique to kidney disease, that increase arterial stiffness. Lysyl oxidase (LOX) is a key mediator of collagen cross linking and matrix remodeling. LOX is predominantly expressed in the cardiovascular system, and its upregulation has been associated with increased tissue stiffening and extracellular matrix remodeling. Thus, this study was designed to evaluate the role of increased LOX activity in inducing aortic stiffness in CKD and whether β-aminopropionitrile (BAPN), a LOX inhibitor, could prevent aortic stiffness by reducing collagen cross linking. Eight-week-old male C57BL/6 mice were subjected to 5/6 nephrectomy (Nx) or sham surgery. Two weeks after surgery, mice were randomized to BAPN (300 mg/kg/day in water) or vehicle treatment for 4 wk. Aortic stiffness was assessed by pulse wave velocity (PWV) using Doppler ultrasound. Aortic levels of LOX were assessed by ELISA, and cross-linked total collagen levels were analyzed by mass spectrometry and Sircol assay. Nx mice showed increased PWV and aortic wall remodeling compared with control mice. Collagen cross linking was increased in parallel with the increases in total collagen in the aorta of Nx mice. In contrast, Nx mice that received BAPN treatment showed decreased cross-linked collagens and PWV compared with that received vehicle treatment. Our results indicated that LOX might be an early and key mediator of aortic stiffness in CKD.NEW & NOTEWORTHY Arterial stiffness in CKD is associated with adverse cardiovascular outcomes. However, the mechanisms underlying increased aortic stiffness in CKD are unclear. Herein, we demonstrated that 1) increased aortic stiffness in CKD is independent of hypertension and calcification and 2) LOX-mediated changes in extracellular matrix are at least in part responsible for increased aortic stiffness in CKD. Prevention of excess LOX may have therapeutic potential in alleviating increased aortic stiffness and improving cardiovascular disease in CKD.

Drug-Induced Gingival Overgrowth—Molecular Aspects of Drug Actions

Drug-induced gingival overgrowth (DIGO) is one of the side effects produced by therapeutic agents, most commonly phenytoin, nifedipine and cyclosporin A. However, the precise mechanism of DIGO is not entirely understood. A literature search of the MEDLINE/PubMed databases was conducted to identify the mechanisms involved in DIGO. The available information suggests that the pathogenesis of DIGO is multifactorial, but common pathogenic sequelae of events emerge, i.e., sodium and calcium channel antagonism or disturbed intracellular handling of calcium, which finally lead to reductions in intracellular folic acid levels. Disturbed cellular functions, mainly in keratinocytes and fibroblasts, result in increased collagen and glycosaminoglycans accumulation in the extracellular matrix. Dysregulation of collagenase activity, as well as integrins and membrane receptors, are key mechanisms of reduced degradation or excessive synthesis of connective tissue components. This manuscript describes the cellular and molecular factors involved in the epithelial–mesenchymal transition and extracellular matrix remodeling triggered by agents producing DIGO.

Prediction and analysis of osteoarthritis hub genes with bioinformatics

Background

Osteoarthritis (OA) is the most common type of arthritis. OA can cause joint pain, stiffness, and loss of function. The pathogenesis of OA is not completely clear. Moreover, there is no effective treatment, and clinical management is limited to symptomatic relief or joint surgery. This study utilized bioinformatics to analyze normal and OA articular cartilage samples to find biomarkers and therapeutic targets for OA.

Methods

The GSE169077 gene chip dataset was downloaded from the public gene chip data platform of the National Biotechnology Information Center. The dataset included 6 samples of OA tissues and 5 samples of healthy cartilage tissues. Differentially expressed genes (DEGs) were screened using the R language "limma" function package under the threshold of log₂[fold change (FC)] ≥2 and a P value <0.05. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathways of the target genes were enriched and analyzed using the database for annotation, visualization, and integrated discovery (DAVID), and a protein-protein interaction (PPI) network was further constructed using the search tool for the retrieval of interacting genes/proteins (STRING) database. The coexpression relationship of the genes in the module was visualized and screened with Cytoscape.

Results

A total of 27 DEGs were identified, including 9 downregulated genes and 18 upregulated genes. GO signal pathway enrichment analysis showed involvement in hypoxic response, fibrous collagen trimer, and extracellular matrix structural components. KEGG analysis demonstrated associations with protein digestion and absorption, extracellular matrix receptor interaction, and the peroxisome proliferator-activated receptor signal pathway, among several other pathways. A PPI network was obtained through STRING analysis, and the results were imported into Cytoscape software. The 27 DEGs were sequenced by the cytoHubba plug-in by various calculation methods, and 5 hub genes (COL1A1, COL1A2, POSTN, BMP1, and MMP13) were finally selected. These genes were analyzed by PPI again and annotated with GO and KEGG in different colors.

Conclusions

Bioinformatics technology effectively identified differential genes in the knee cartilage tissue of healthy controls and patients with OA, providing opportunities to further explore the mechanism and treatment of OA on a transcriptional level.

Targeting Periostin Expression Makes Pancreatic Cancer Spheroids More Vulnerable to Natural Killer Cells

Pancreatic cancer (PaCa) characteristically has a dense tumor microenvironment, which results in poor patient prognosis. Pancreatic stellate cells (PSCs) are the most abundant cells in the PaCa microenvironment and the principal source of collagen. Periostin, a matricellular protein, is produced specifically by PSCs and promotes the aggressiveness of PaCa cells by facilitating extracellular collagen assembly. Here, we aimed to decrease extracellular collagen assembly by suppressing periostin, thereby increasing the cytotoxic activity of natural killer (NK) cells. Periostin expression was suppressed in PSCs (called PSC-P) using CRISPR-Cas9. PaCa cells (BxPC-3) were co-cultured with PSC and PSC-P cells in a 3D environment to form tumor spheroids mimicking the tumor microenvironment. The extracellular collagen production of spheroids was evaluated by Masson's trichrome staining. The cytotoxic activity of NK-92 cells was analyzed by flow cytometry and confocal microscopy via CD107a staining. Cell death in BxPC-3 cells was evaluated by measuring Annexin-V and PI positivity using flow cytometry. As a result, periostin suppression decreased extracellular collagen and increased the infiltration of NK-92 cells into spheroids, and induced cell death in PaCa cells. In conclusion, we suggest that periostin might be a therapeutic target for PaCa and further analysis is warranted using in vivo models for proof-of-concept.

The Multiple Roles of Periostin in Non-Neoplastic Disease

Periostin, identified as a matricellular protein and an ECM protein, plays a central role in non-neoplastic diseases. Periostin and its variants have been considered to be normally involved in the progression of most non-neoplastic diseases, including brain injury, ocular diseases, chronic rhinosinusitis, allergic rhinitis, dental diseases, atopic dermatitis, scleroderma, eosinophilic esophagitis, asthma, cardiovascular diseases, lung diseases, liver diseases, chronic kidney diseases, inflammatory bowel disease, and osteoarthrosis. Periostin interacts with protein receptors and transduces signals primarily through the PI3K/Akt and FAK two channels as well as other pathways to elicit tissue remodeling, fibrosis, inflammation, wound healing, repair, angiogenesis, tissue regeneration, bone formation, barrier, and vascular calcification. This review comprehensively integrates the multiple roles of periostin and its variants in non-neoplastic diseases, proposes the utility of periostin as a biological biomarker, and provides potential drug-developing strategies for targeting periostin.

Fat, adipokines, bone structure and bone regulatory factors associations in obesity

CONTEXT

Obese (OB) adults (BMI ≥ 30) have a higher bone mineral density (BMD) and more favourable bone microarchitecture than normal-weight (NW) adults (BMI 18.5-24.9).

OBJECTIVE

The objective of this study was to identify which fat compartments have the strongest association with bone density and bone turnover and whether biochemical factors (adipokines, hormones and bone regulators) are likely to be important mediators of the effect of obesity on bone.

DESIGN

This was a cross-sectional, observational, matched case-control study.

SETTING

Participants were recruited from the local community.

PARTICIPANTS

Two hundred healthy men and women aged 25-40 or 55-75 were recruited in individually matched OB and NW pairs. Body composition, BMD and bone microarchitecture were determined by dual-energy X-ray absorptiometry (DXA), computed tomography (CT) and high-resolution peripheral CT (HR-pQCT). Bone turnover and potential regulators such as C-terminal cross-linking telopeptide (CTX), type 1 procollagen N-terminal peptide (PINP), sclerostin, periostin, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), insulin-like growth factor 1 (IGF1), adiponectin, leptin and insulin were assessed.

MAIN OUTCOME

Planned exploratory analysis of the relationships between fat compartments, areal and volumetric BMD, bone microarchitecture, bone turnover markers and bone regulators.

RESULTS

Compared with NW, OB had lower CTX, PINP, adiponectin, IGF1, and 25OHD and higher leptin, PTH and insulin (all P < 0.05). CTX and subcutaneous adipose tissue (SAT) were the bone marker and fat compartment most consistently associated with areal and volumetric BMD. In regression models, SAT was negatively associated with CTX (P < 0.001). When leptin was added to the model, SAT was no longer associated with CTX, but leptin (P < 0.05) was negatively associated with CTX.

CONCLUSIONS

SAT is associated with lower bone resorption and properties favourable for bone strength in obesity. Leptin may be an important mediator of the effects of SAT on the skeleton.

Expression of procollagen C-proteinase enhancer 1 in human trabecular meshwork tissues and cells

Glaucoma is a primary cause of progressive, irreversible blindness. One of the primary tissues involved in glaucoma pathology is the trabecular meshwork (TM). In glaucoma, the TM is a site of increased extracellular matrix (ECM) protein secretion, deposition, and accumulation, contributing to a disrupted TM architecture and increased resistance to the outflow of aqueous humor. The healthy TM structure is comprised of sheets and beams composed of multiple extracellular matrix proteins, including mature fibrillar collagens. In the glaucomatous eye, this structure is disrupted by the abnormal deposition of collagen fibrils and other ECM proteins in the TM. In this study, we determined whether procollagen C-proteinase enhancer 1 (PCOLCE1) - a protein typically involved in collagen fibril processing - is expressed in the human TM tissues and cells and whether its expression is altered in glaucomatous conditions. Using immunocytochemistry, qPCR, and western blot (WB) analyses, we found that PCOLCE1 is expressed and translated in human TM tissues and cells. Our data analysis suggests that PCOLCE1 expression by TM cells may be downregulated by TGFβ2 treatment, which warrants further investigation of a possible role for PCOLCE1 in glaucomatous pathology.

Periostin: biology and function in cancer

Periostin (POSTN), a member of the matricellular protein family, is a secreted adhesion-related protein produced in the periosteum and periodontal ligaments. Matricellular proteins are a nonstructural family of extracellular matrix (ECM) proteins that regulate a wide range of biological processes in both normal and pathological conditions. Recent studies have demonstrated the key roles of these ECM proteins in the tumor microenvironment. Furthermore, periostin is an essential regulator of bone and tooth formation and maintenance, as well as cardiac development. Also, periostin interacts with multiple cell-surface receptors, especially integrins, and triggers signals that promote tumor growth. According to recent studies, these signals are implicated in cancer cell survival, epithelial-mesenchymal transition (EMT), invasion, and metastasis. In this review, we will summarize the most current data regarding periostin, its structure and isoforms, expressions, functions, and regulation in normal and cancerous tissues. Emphasis is placed on its association with cancer progression, and also future potential for periostin-targeted therapeutic approaches will be explored.

Bioactive extracellular matrix fragments in tendon repair

Tendinopathy is a common tendon disorder that causes pain, loss of strength and function, and local inflammation mainly characterized by hypoxia, collagen degradation, and extracellular matrix (ECM) disorganization. Generally, ECM degradation and remodeling is tightly regulated; however, hyperactivation of matrix metalloproteases (MMPs) contributes to excessive collagenolysis under pathologic conditions resulting in tendon ECM degradation. This review article focuses on the production, function, and signaling of matrikines for tendon regeneration following injury with insights into the expression, tissue compliance, and cell proliferation exhibited by various matrikines. Furthermore, the regenerative properties suggest translational significance of matrikines to improve the outcomes post-injury by assisting with tendon healing.

The Extracellular Matrix Environment of Clear Cell Renal Cell Carcinoma

Simple Summary

The extracellular matrix (ECM) controls fundamental properties of tumors, including growth, blood vessel investment, and invasion. The ECM defines rigidity of tumor tissue and individual ECM proteins have distinct biological effects on tumor cells. This article reviews the composition and biological functions of the ECM of clear cell renal cell carcinoma (ccRCC). The most frequent initiating genetic mutation in ccRCC inactivates the VHL gene, which plays a direct role in organizing the ECM. This is predicted to result in local ECM modification, which promotes the growth of tumor cells and the invasion of blood vessels. Later in tumor growth, connective tissue cells are recruited, which are predicted to produce large amounts of ECM, affecting the growth and invasive behaviors of tumor cells. Strategies to therapeutically control the ECM are under active investigation and a better understanding of the ccRCC ECM will determine the applicability of ECM-modifying drugs to this type of cancer.

Abstract

The extracellular matrix (ECM) of tumors is a complex mix of components characteristic of the tissue of origin. In the majority of clear cell renal cell carcinomas (ccRCCs), the tumor suppressor VHL is inactivated. VHL controls matrix organization and its loss promotes a loosely organized and angiogenic matrix, predicted to be an early step in tumor formation. During tumor evolution, cancer-associated fibroblasts (CAFs) accumulate, and they are predicted to produce abundant ECM. The ccRCC ECM composition qualitatively resembles that of the healthy kidney cortex in which the tumor arises, but there are important differences. One is the quantitative difference between a healthy cortex ECM and a tumor ECM; a tumor ECM contains a higher proportion of interstitial matrix components and a lower proportion of basement membrane components. Another is the breakdown of tissue compartments in the tumor with mixing of ECM components that are physically separated in healthy kidney cortex. Numerous studies reviewed in this work reveal effects of specific ECM components on the growth and invasive behaviors of ccRCCs, and extrapolation from other work suggests an important role for ECM in controlling ccRCC tumor rigidity, which is predicted to be a key determinant of invasive behavior.

Periostin as a biomarker in chronic rhinosinusitis: A contemporary systematic review

BACKGROUND

The role of periostin, a matricellular protein encoded by the POSTN gene, in chronic rhinosinusitis with nasal polyposis (CRSwNP) is reviewed. Periostin is considered a potential biomarker of endotype and may be useful for evaluating response to treatment.

METHODS

Search terms in PubMed and Web of Science (1990-March 2022) included: ((periostin) OR (POSTN)) AND ((sinusitis) OR (nasal polyp) OR (CRSwNP) OR (CRS). The primary outcomes were differences in tissue, serum, and nasal lavage between CRSwNP and CRS without NP (CRSsNP) or controls. Associated factors reported to affect periostin expression, data regarding participants' clinical characteristics, disease endotypes, laboratory methods, and samples' origin were also pooled. Studies on <10 patients were excluded.

RESULTS

Out of 101 records harvested through database searching, 29 prospective cross-sectional or case-control studies were eligible for review and qualitative analysis. Tissue sample origin, concurrent infection, current and past medication, primary or recurrent disease, allergic rhinitis, and smoking status should be considered as confounding factors for periostin levels. Periostin and POSTN messenger RNA (mRNA) levels were consistently and significantly higher in CRSwNP than CRSsNP and controls. Despite the distinctly different inflammation patterns among CRSwNP endotypes, periostin-related remodeling patterns seemed to be similar.

CONCLUSION

Tissue and serum periostin levels, and POSTN expression appear elevated in CRSwNP, especially in eosinophilic inflammation, compared to CRSsNP and controls. Disease severity and comorbidities are also reflected in periostin and POSTN values. Carefully designed prospective studies may establish the role of periostin as a biomarker in CRSwNP and allow its incorporation in clinical practice.

The Role of Extracellular Matrix Proteins in Breast Cancer

The extracellular matrix is a structure composed of many molecules, including fibrillar (types I, II, III, V, XI, XXIV, XXVII) and non-fibrillar collagens (mainly basement membrane collagens: types IV, VIII, X), non-collagenous glycoproteins (elastin, laminin, fibronectin, thrombospondin, tenascin, osteopontin, osteonectin, entactin, periostin) embedded in a gel of negatively charged water-retaining glycosaminoglycans (GAGs) such as non-sulfated hyaluronic acid (HA) and sulfated GAGs which are linked to a core protein to form proteoglycans (PGs). This highly dynamic molecular network provides critical biochemical and biomechanical cues that mediate the cell–cell and cell–matrix interactions, influence cell growth, migration and differentiation and serve as a reservoir of cytokines and growth factors’ action. The breakdown of normal ECM and its replacement with tumor ECM modulate the tumor microenvironment (TME) composition and is an essential part of tumorigenesis and metastasis, acting as key driver for malignant progression. Abnormal ECM also deregulate behavior of stromal cells as well as facilitating tumor-associated angiogenesis and inflammation. Thus, the tumor matrix modulates each of the classically defined hallmarks of cancer promoting the growth, survival and invasion of the cancer. Moreover, various ECM-derived components modulate the immune response affecting T cells, tumor-associated macrophages (TAM), dendritic cells and cancer-associated fibroblasts (CAF). This review article considers the role that extracellular matrix play in breast cancer. Determining the detailed connections between the ECM and cellular processes has helped to identify novel disease markers and therapeutic targets.

FBN2 Silencing Recapitulates Hypoxic Conditions and Induces Elastic Fiber Impairment in Human Dermal Fibroblasts

Most chronic wounds are characterized by varying degrees of hypoxia and low partial pressures of O2 that may favor the development of the wound and/or delay healing. However, most studies regarding extracellular matrix remodeling in wound healing are conducted under normoxic conditions. Here, we investigated the consequences of hypoxia on elastic network formation, both in a mouse model of pressure-induced hypoxic ulcer and in human primary fibroblasts cultured under hypoxic conditions. In vitro, hypoxia inhibited elastic fiber synthesis with a reduction in fibrillin-2 expression at the mRNA and protein levels. Lysyl oxidase maturation was reduced, concomitant with lower enzymatic activity. Fibrillin-2 and lysyl oxidase could interact directly, whereas the downregulation of fibrillin-2 was associated with deficient lysyl oxidase maturation. Elastic fibers were not synthesized in the hypoxic inflammatory tissues resulting from in vivo pressure-induced ulcer. Tropoelastin and fibrillin-2 were expressed sparsely in hypoxic tissues stained with carbonic anhydrase IX. Different hypoxic conditions in culture resulted in the arrest of elastic fiber synthesis. The present study demonstrated the involvement of FBN2 in regulating elastin deposition in adult skin models and described the specific impact of hypoxia on the elastin network without consequences on collagen and fibronectin networks.

Lysyl oxidase promotes anaplastic thyroid carcinoma cell proliferation and metastasis mediated via BMP1

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is an extremely aggressive solid tumor with no effective treatment at present. Because of the rapid growth and aggressiveness, nearly all patients die within six months after developing ATC. Hence, more research regarding novel therapeutic targets for ATC is urgently needed.

METHODS

Single-cell RNA sequencing data and microarray data of ATC were retrieved from the Gene Expression Omnibus (GEO) database. Cell clustering was performed using the Seurat package. Then, differential expression and functional enrichment analyses were performed. Gene set enrichment analysis (GSEA) was further used to investigate the functional enrichment of lysyl oxidase (LOX) and bone morphogenetic protein-1 (BMP1). The expression levels of LOX and BMP1 were measured using quantitative real-time PCR and Western blot. LOX and BMP1 were knocked down using si-RNAs. Cell proliferation was evaluated by the CCK-8 and clone formation assays. Cell migration and invasion were assessed by the wound healing assay and Transwell assay, respectively.

RESULTS

LOX was upregulated at the single-cell level, as well as in ATC tissues and cell lines. LOX knockdown significantly inhibited ATC cell proliferation. Furthermore, the migration and invasion of ATC cells were remarkably inhibited after LOX inhibition. In addition, BMP1 regulated LOX expression in 8505C cells, while BMP1 overexpression restored the LOX activity blocked by the LOX inhibitor BAPN. BMP1 could also induce the cell proliferation and metastasis of ATC.

CONCLUSIONS

LOX/BMP1 mediates the malignant progression of ATC, highlighting the potential application of LOX/BMP1 in the treatment of ATC. This study provides new insights for efficient therapeutic agents based on the LOX/BMP1 axis.

Tumor Microenvironment in Pancreatic Intraepithelial Neoplasia

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive neoplasm with a poor survival rate. This is mainly due to late detection, which substantially limits therapy options. A better understanding of the early phases of pancreatic carcinogenesis is fundamental for improving patient prognosis in the future. In this article, we focused on the tumor microenvironment (TME), which provides the biological niche for the development of PDAC from its most common precursor lesions, PanIN (pancreatic intraepithelial neoplasias).

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors with a poor prognosis. A characteristic of PDAC is the formation of an immunosuppressive tumor microenvironment (TME) that facilitates bypassing of the immune surveillance. The TME consists of a desmoplastic stroma, largely composed of cancer-associated fibroblasts (CAFs), immunosuppressive immune cells, immunoregulatory soluble factors, neural network cells, and endothelial cells with complex interactions. PDAC develops from various precursor lesions such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), and possibly, atypical flat lesions (AFL). In this review, we focus on the composition of the TME in PanINs to reveal detailed insights into the complex restructuring of the TME at early time points in PDAC progression and to explore ways of modifying the TME to slow or even halt tumor progression.

Periostin gene expression in neu-positive breast cancer cells is regulated by a FGFR signaling cross talk with TGFβ/PI3K/AKT pathways

Background

Breast cancer is a highly heterogeneous disease with multiple drivers and complex regulatory networks. Periostin (Postn) is a matricellular protein involved in a plethora of cancer types and other diseases. Postn has been shown to be involved in various processes of tumor development, such as angiogenesis, invasion, cell survival and metastasis. The expression of Postn in breast cancer cells has been correlated with a more aggressive phenotype. Despite extensive research, it remains unclear how epithelial cancer cells regulate Postn expression.

Methods

Using murine tumor models and human TMAs, we have assessed the proportion of tumor samples that have acquired Postn expression in tumor cells. Using biochemical approaches and tumor cell lines derived from Neu+ murine primary tumors, we have identified major regulators of Postn gene expression in breast cancer cell lines.

Results

Here, we show that, while the stromal compartment typically always expresses Postn, about 50% of breast tumors acquire Postn expression in the epithelial tumor cells. Furthermore, using an in vitro model, we show a cross-regulation between FGFR, TGFβ and PI3K/AKT pathways to regulate Postn expression. In HER2-positive murine breast cancer cells, we found that basic FGF can repress Postn expression through a PKC-dependent pathway, while TGFβ can induce Postn expression in a SMAD-independent manner. Postn induction following the removal of the FGF-suppressive signal is dependent on PI3K/AKT signaling.

Conclusion

Overall, these results reveal a novel regulatory mechanism and shed light on how breast tumor cells acquire Postn expression. This complex regulation is likely to be cell type and cancer specific as well as have important therapeutic implications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01487-8.

Smooth muscle-specific MMP17 (MT4-MMP) regulates the intestinal stem cell niche and regeneration after damage

Smooth muscle is an essential component of the intestine, both to maintain its structure and produce peristaltic and segmentation movements. However, very little is known about other putative roles that smooth muscle cells may have. Here, we show that smooth muscle cells may be the dominant suppliers of BMP antagonists, which are niche factors essential for intestinal stem cell maintenance. Furthermore, muscle-derived factors render epithelium reparative and fetal-like, which includes heightened YAP activity. Mechanistically, we find that the membrane-bound matrix metalloproteinase MMP17, which is exclusively expressed by smooth muscle cells, is required for intestinal epithelial repair after inflammation- or irradiation-induced injury. Furthermore, we propose that MMP17 affects intestinal epithelial reprogramming after damage indirectly by cleaving diffusible factor(s) such as the matricellular protein PERIOSTIN. Together, we identify an important signaling axis that establishes a role for smooth muscle cells as modulators of intestinal epithelial regeneration and the intestinal stem cell niche.

Pro-inflammatory immunity supports fibrosis advancement in epidermolysis bullosa: intervention with Ang-(1-7)

Recessive dystrophic epidermolysis bullosa (RDEB), a genetic skin blistering disease, is a paradigmatic condition of tissue fragility-driven multi-organ fibrosis. Here, longitudinal analyses of the tissue proteome through the course of naturally developing disease in RDEB mice revealed that increased pro-inflammatory immunity associates with fibrosis evolution. Mechanistically, this fibrosis is a consequence of altered extracellular matrix organization rather than that of increased abundance of major structural proteins. In a humanized system of disease progression, we targeted inflammatory cell fibroblast communication with Ang-(1-7)-an anti-inflammatory heptapeptide of the renin-angiotensin system, which reduced the fibrosis-evoking aptitude of RDEB cells. In vivo, systemic administration of Ang-(1-7) efficiently attenuated progression of multi-organ fibrosis and increased survival of RDEB mice. Collectively, our study shows that selective down-modulation of pro-inflammatory immunity may mitigate injury-induced fibrosis. Furthermore, together with published data, our data highlight molecular diversity among fibrotic conditions. Both findings have direct implications for the design of therapies addressing skin fragility and fibrosis.

Periostin: An Emerging Molecule With a Potential Role in Spinal Degenerative Diseases

Periostin, an extracellular matrix protein, is widely expressed in a variety of tissues and cells. It has many biological functions and is related to many diseases: for example, it promotes cell proliferation and differentiation in osteoblasts, which are closely related to osteoporosis, and mediates cell senescence and apoptosis in chondrocytes, which are involved in osteoarthritis. Furthermore, it also plays an important role in mediating inflammation and reconstruction during bronchial asthma, as well as in promoting bone development, reconstruction, repair, and strength. Therefore, periostin has been explored as a potential biomarker for various diseases. Recently, periostin has also been found to be expressed in intervertebral disc cells as a component of the intervertebral extracellular matrix, and to play a crucial role in the maintenance and degeneration of intervertebral discs. This article reviews the biological role of periostin in bone marrow-derived mesenchymal stem cells, osteoblasts, osteoclasts, chondrocytes, and annulus fibrosus and nucleus pulposus cells, which are closely related to spinal degenerative diseases. The study of its pathophysiological effects is of great significance for the diagnosis and treatment of spinal degeneration, although additional studies are needed.

Periostin in Allergy and Inflammation

Matricellular proteins are involved in the crosstalk between cells and their environment and thus play an important role in allergic and inflammatory reactions. Periostin, a matricellular protein, has several documented and multi-faceted roles in health and disease. It is differentially expressed, usually upregulated, in allergic conditions, a variety of inflammatory diseases as well as in cancer and contributes to the development and progression of these diseases. Periostin has also been shown to influence tissue remodelling, fibrosis, regeneration and repair. In allergic reactions periostin is involved in type 2 immunity and can be induced by IL-4 and IL-13 in bronchial cells. A variety of different allergic diseases, among them bronchial asthma and atopic dermatitis (AD), have been shown to be connected to periostin expression. Periostin is commonly expressed in fibroblasts and acts on epithelial cells as well as fibroblasts involving integrin and NF-κB signalling. Also direct signalling between periostin and immune cells has been reported. The deposition of periostin in inflamed, often fibrotic, tissues is further fuelling the inflammatory process. There is increasing evidence that periostin is also expressed by epithelial cells in several of the above-mentioned conditions as well as in cancer. Augmented periostin expression has also been associated with chronic inflammation such as in inflammatory bowel disease (IBD). Periostin can be expressed in a variety of different isoforms, whose functions have not been elucidated yet. This review will discuss potential functions of periostin and its different isoforms in allergy and inflammation.

Enzymatic cross-linking of collagens in organ fibrosis - resolution and assessment

Introduction: Enzymatic cross-linking of the collagens within the extracellular matrix (ECM) catalyzed by enzymes such as lysyl oxidase (LOX) and lysyl oxidase like-enzymes 1-4 (LOXL), transglutaminase 2 (TG2), and peroxidasin (PXDN) contribute to fibrosis progression through extensive collagen cross-linking. Studies in recent years have begun elucidating the important role of collagen cross-linking in perpetuating progression of organ fibrosis independently of inflammation through an increasingly stiff and noncompliant ECM. Therefore, collagen cross-linking and the cross-linking enzymes have become new targets in anti-fibrotic therapy as well as targets of novel biomarkers to properly assess resolution of the fibrotic ECM.Areas covered: The enzymatic actions of enzymes catalyzing collagen cross-linking and their relevance in organ fibrosis. Potential biomarkers specifically quantifying proteolytic fragments of collagen cross-linking is discussed based on Pubmed search done in November 2020 as well as the authors knowledge.Expert opinion: Current methods for the assessment of fibrosis involve the use of invasive and/or cumbersome and expensive methods such as tissue biopsies. Thus, an unmet need exists for the development and validation of minimally invasive biomarkers of proteolytic fragments of cross-linked collagens. These biomarkers may aid in the development and proper assessment of fibrosis resolution in coming years.

Tengdan Capsule Prevents Hypertensive Kidney Damage in SHR by Inhibiting Periostin-Mediated Renal Fibrosis

BACKGROUND: Hypertension-induced renal damage is a serious and complex condition that has not been effectively treated by conventional blood pressure-lowering drugs. Tengdan capsule (TDC) is a China FDA-approved compound herbal medicine for treating hypertension; however, its chemical basis and pharmacological efficacy have not been fully investigated in a preclinical setting.

METHODS: High-performance liquid chromatography (HPLC) was used to identify and quantify the major chemical components of TDC extracted from ultrapure water. Adult spontaneously hypertensive rats (SHR) and age/sex-matched Wistar Kyoto normotensive rats (WKY) were both treated with TDC, losartan, or saline for one month, and their blood pressure (BP) was monitored at the same time by tail-cuff BP system. Biochemical indexes such as urine creatinine (CRE) and blood urea nitrogen (BUN) were determined. Kidney tissue sections were examined with (H&E), and Masson staining to evaluate the pathological effect of TDC on SHR’s kidneys. After TDC treatment, the differentially expressed proteins in the kidneys of SHR were identified by the TMT-based quantitative proteomics analysis, which may provide the targets and possible mechanisms of TDC action. In addition, Western blot analysis, RT-qPCR, and ELISA assays were carried out to further verify the proteomics findings. Finally, two different models involving in vitro renal injuries were established using human kidney HEK293 cells; and the molecular mechanism of TDC kidney protection was demonstrated.

RESULTS: Seven chemical compounds, namely Notoginsenoside R1, Ginsenoside RG1, Ginsenoside Re, Ginsenoside Rb1, Sodium Danshensu, Protocatechualdehyde, and Salvianolic acid B, were identified and quantified from the water-soluble extracts of TDC by HPLC. In vivo study using rats showed that TDC effectively reduced BP, BUN, and CRE levels and attenuated renal fibrosis in SHR, and ameliorated damage to the kidneys. Proteomics and subsequent bioinformatics analyses indicated that periostin-mediated inflammatory response and TGFβ/Smad signaling pathway proteins were closely related to the therapeutic effect of TDC in rat kidneys. Western blot analysis and RT-qPCR showed that TDC markedly downregulated the mRNA and protein expression of periostin in renal tissues compared to the untreated SHR. In addition, TGF-β and COL1A1 mRNA levels also decreased in SHR renal tissues following TDC treatment. In vitro studies showed that low to medium doses of TDC down-regulated the expression of periostin in the injury model of HEK293 cell. In addition, medium to high doses of TDC significantly inhibited collagen deposition in TGFβ1-induced HEK293 cell fibrosis.

CONCLUSIONS: Major components from the compound herbal medicine Tengdan Capsule are identified and quantified. TDC effectively lowers blood pressure and protects against renal damage caused by hypertension in SHR. Mechanistically, TDC blocks periostin by regulating the TGF-β/Smad signaling pathway in the kidney, both in vivo and in vitro. Preventing periostin-mediated renal fibrosis and inflammation might be a promising strategy for treating a hypertensive renal injury.

The Potential Role of Airways Periostin in the Clinical Practice of Patients Affected by Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic debilitating fibrotic lung disease leading to respiratory failure and ultimately to death. Noninvasive biomarkers, for the early diagnosis, differential diagnosis, prognosis, and prediction of therapeutic response, are needed. Previous studies support a role for periostin in lung fibrosis. The aim of our study was to analyze periostin levels in the airways of patients with IPF and to investigate its role as a useful predictive biomarker of the disease. We enrolled 30 IPF patients and 5 control subjects. All subjects underwent all standard radiological, functional, and biological examinations for IPF diagnosis and staging and exhaled breath condensate (EBC) collection. Periostin was assessed by an enzyme-linked immunosorbent assay kit on EBC. Periostin was dosable in the EBC of all subjects enrolled. We found higher exhaled periostin levels in IPF patients than healthy controls (65.5 ± 23.5 pg/mL vs. 33 ± 21.4 pg/mL, p < 0.05). Moreover, in receiver operating characteristic analysis, the clinical reference value of periostin was 37.88 pg/mL to discriminate patients with IPF from healthy subjects, with the area under the curve of 0.8815. There was no significant correlation between periostin levels and gender or pulmonary function tests. These preliminary results support our working hypothesis that periostin is dosable in the airways of patients with IPF. As the circulating periostin, also airways periostin may be a potential biomarker to support IPF diagnosis and to monitor disease progression during follow-up.

Functional regeneration and repair of tendons using biomimetic scaffolds loaded with recombinant periostin

Tendon injuries disrupt the balance between stability and mobility, causing compromised functions and disabilities. The regeneration of mature, functional tendons remains a clinical challenge. Here, we perform transcriptional profiling of tendon developmental processes to show that the extracellular matrix-associated protein periostin (Postn) contributes to the maintenance of tendon stem/progenitor cell (TSPC) functions and promotes tendon regeneration. We show that recombinant periostin (rPOSTN) promotes the proliferation and stemness of TSPCs, and maintains the tenogenic potentials of TSPCs in vitro. We also find that rPOSTN protects TSPCs against functional impairment during long-term passage in vitro. For in vivo tendon formation, we construct a biomimetic parallel-aligned collagen scaffold to facilitate TSPC tenogenesis. Using a rat full-cut Achilles tendon defect model, we demonstrate that scaffolds loaded with rPOSTN promote endogenous TSPC recruitment, tendon regeneration and repair with native-like hierarchically organized collagen fibers. Moreover, newly regenerated tendons show recovery of mechanical properties and locomotion functions.

The regeneration of functional tendons remains a clinical challenge. Here the authors develop a biomimetic scaffold loaded with recombinant periostin and demonstrate its functionality in promoting tendon stem/progenitor cell recruitment and tenogenic differentiation, and tendon regeneration in a rat full-cut Achilles tendon defect model.

Comparative Transcriptomic and Expression Profiles Between the Foot Muscle and Mantle Tissues in the Giant Triton Snail Charonia tritonis

The giant triton snail (Charonia tritonis), an endangered gastropod species of ecological and economic importance, is widely distributed in coral reef ecosystems of the Indo-West Pacific region and the tropical waters of the South China Sea. Limited research on molecular mechanisms can be conducted because the complete genomic information on this species is unavailable. Hence, we performed transcriptome sequencing of the C. tritonis foot muscle and mantle using the Illumina HiSeq sequencing platform. In 109,722 unigenes, we detected 7,994 (3,196 up-regulated and 4,798 down-regulated) differentially expressed genes (DEGs) from the C. tritonis foot muscle and mantle transcriptomes. These DEGs will provide valuable resources to improve the understanding of molecular mechanisms involved in biomineralization of C. tritonis. In the Gene Ontology (GO) database, DEGs were clustered into three main categories (biological processes, molecular functions, and cellular components) and were involved in 50 functional subcategories. The top 20 GO terms in the molecular function category included sulfotransferase activity, transferring sulfur-containing groups, and calcium ion binding, which are terms considered to be related to biomineralization. In KEGG classifications, transcriptomic DEGs were mainly enriched in glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate, and sulfur metabolism pathway, which may be related to biomineralization. The results of qPCR showed that three of the eight genes examined were significantly up-regulated in the mantle. The phylogenetic tree of BMP1 suggested a significant divergence between homologous genes in C. tritonis. Our results improve the understanding of biomineralization in C. tritonis and provide fundamental transcriptome information to study other molecular mechanisms such as reproduction.

Targeting Lysyl Oxidase Family Meditated Matrix Cross-Linking as an Anti-Stromal Therapy in Solid Tumours

Simple Summary

To improve efficacy of solid cancer treatment, efforts have shifted towards targeting both the cancer cells and the surrounding tumour tissue they grow in. The lysyl oxidase (LOX) family of enzymes underpin the fibrotic remodeling of the tumour microenvironment to promote both cancer growth, spread throughout the body and modulate response to therapies. This review examines how the lysyl oxidase family is involved in tumour development, how they can be targeted, and their potential as diagnostic and prognostic biomarkers in solid tumours.

Abstract

The lysyl oxidase (LOX) family of enzymes are a major driver in the biogenesis of desmoplastic matrix at the primary tumour and secondary metastatic sites. With the increasing interest in and development of anti-stromal therapies aimed at improving clinical outcomes of cancer patients, the Lox family has emerged as a potentially powerful clinical target. This review examines how lysyl oxidase family dysregulation in solid cancers contributes to disease progression and poor patient outcomes, as well as an evaluation of the preclinical landscape of LOX family targeting therapeutics. We also discuss the suitability of the LOX family as a diagnostic and/or prognostic marker in solid tumours.

Pivotal Role of Tenascin-W (-N) in Postnatal Incisor Growth and Periodontal Ligament Remodeling

The continuously growing mouse incisor provides a fascinating model for studying stem cell regulation and organ renewal. In the incisor, epithelial and mesenchymal stem cells assure lifelong tooth growth. The epithelial stem cells reside in a niche known as the cervical loop. Mesenchymal stem cells are located in the nearby apical neurovascular bundle and in the neural plexus. So far, little is known about extracellular cues that are controlling incisor stem cell renewal and guidance. The extracellular matrix protein tenascin-W, also known as tenascin-N (TNN), is expressed in the mesenchyme of the pulp and of the periodontal ligament of the incisor, and is closely associated with collagen 3 fibers. Here, we report for the first time the phenotype of tenascin-W/TNN deficient mice, which in a C57BL/6N background exhibit a reduced body weight and lifespan. We found major defects in the alveolar bone and periodontal ligament of the growing rodent incisors, whereas molars were not affected. The alveolar bone around the incisor was replaced by a dense scar-like connective tissue, enriched with newly formed nerve fibers likely leading to periodontal pain, less food intake and reduced body weight. Using soft food to reduce mechanical load on the incisor partially rescued the phenotype. In situ hybridization and Gli1 reporter mouse experiments revealed decreased hedgehog signaling in the incisor mesenchymal stem cell compartment, which coordinates the development of mesenchymal stem cell niche. These results indicate that TNN deficiency in mice affects periodontal remodeling and increases nerve fiber branching. Through periodontal pain the food intake is reduced and the incisor renewal and the neurovascular sonic hedgehog secretion rate are reduced. In conclusion, tenascin-W/TNN seems to have a primary function in rapid periodontal tissue remodeling and a secondary function in mechanosensation.

Extracellular Matrix in Calcific Aortic Valve Disease: Architecture, Dynamic and Perspectives

Calcific Aortic Valve Disease (CAVD) is the most common valvular heart disease in developed countries and in the ageing population. It is strongly correlated to median age, affecting up to 13% of the population over the age of 65. Pathophysiological analysis indicates CAVD as a result of an active and degenerative disease, starting with sclerosis and chronic inflammation and then leaflet calcification, which ultimately can account for aortic stenosis. Although CAVD has been firstly recognized as a passive event mostly resulting from a degenerative aging process, much evidences suggests that calcification arises from different active processes, involving both aortic valve-resident cells (valve endothelial cells, valve interstitial cells, mesenchymal stem cells, innate immunity cells) and circulating cells (circulating mesenchymal cells, immunity cells). Moreover, a role for the cell-derived "matrix vesicles" and extracellular matrix (ECM) components has also been recognized. The aim of this work is to review the cellular and molecular alterations occurring in aortic valve during CAVD pathogenesis, focusing on the role of ECM in the natural course of the disease.

Immunomodulatory Role of the Extracellular Matrix Within the Liver Disease Microenvironment

Chronic liver disease when accompanied by underlying fibrosis, is characterized by an accumulation of extracellular matrix (ECM) proteins and chronic inflammation. Although traditionally considered as a passive and largely architectural structure, the ECM is now being recognized as a source of potent damage-associated molecular pattern (DAMP)s with immune-active peptides and domains. In parallel, the ECM anchors a range of cytokines, chemokines and growth factors, all of which are capable of modulating immune responses. A growing body of evidence shows that ECM proteins themselves are capable of modulating immunity either directly via ligation with immune cell receptors including integrins and TLRs, or indirectly through release of immunoactive molecules such as cytokines which are stored within the ECM structure. Notably, ECM deposition and remodeling during injury and fibrosis can result in release or formation of ECM-DAMPs within the tissue, which can promote local inflammatory immune response and chemotactic immune cell recruitment and inflammation. It is well described that the ECM and immune response are interlinked and mutually participate in driving fibrosis, although their precise interactions in the context of chronic liver disease are poorly understood. This review aims to describe the known pro-/anti-inflammatory and fibrogenic properties of ECM proteins and DAMPs, with particular reference to the immunomodulatory properties of the ECM in the context of chronic liver disease. Finally, we discuss the importance of developing novel biotechnological platforms based on decellularized ECM-scaffolds, which provide opportunities to directly explore liver ECM-immune cell interactions in greater detail.

FAM20C directly binds to and phosphorylates Periostin

It is widely accepted that FAM20C functions as a Golgi casein kinase and has large numbers of kinase substrates within the secretory pathway. It has been previously reported that FAM20C is required for maintenance of healthy periodontal tissues. However, there has been no report that any extracellular matrix molecules expressed in periodontal tissues are indeed substrates of FAM20C. In this study, we sought to identify the binding partner(s) of FAM20C. FAM20C wild-type (WT) and its kinase inactive form D478A proteins were generated. These proteins were electrophoresed and the Coomassie Brilliant Blue (CBB)-positive bands were analyzed to identify FAM20C-binding protein(s) by Mass Spectrometry (MS) analysis. Periostin was found by the analysis and the binding between FAM20C and Periostin was investigated in cell cultures and in vitro. We further determined the binding region(s) within Periostin responsible for FAM20C-binding. Immunolocalization of FAM20C and Periostin was examined using mouse periodontium tissues by immunohistochemical analysis. In vitro kinase assay was performed using Periostin and FAM20C proteins to see whether FAM20C phosphorylates Periostin in vitro. We identified Periostin as one of FAM20C-binding proteins by MS analysis. Periostin interacted with FAM20C in a kinase-activity independent manner and the binding was direct in vitro. We further identified the binding domain of FAM20C in Periostin, which was mapped within Fasciclin (Fas) I domain 1-4 of Periostin. Immunolocalization of FAM20C was observed in periodontal ligament (PDL) extracellular matrix where that of Periostin was also immunostained in murine periodontal tissues. FAM20C WT, but not D478A, phosphorylated Periostin in vitro. Consistent with the overlapped expression pattern of FAM20C and Periostin, our data demonstrate for the first time that Periostin is a direct FAM20C-binding partner and that FAM20C phosphorylates Periostin in vitro.