Collagen XV, a multifaceted multiplexin present across tissues and species

Assessment of circulating proteins in thyroid cancer: Proteome-wide Mendelian randomization and colocalization analysis

The causality between circulating proteins and thyroid cancer (TC) remains unclear. We employed five large-scale circulating proteomic genome-wide association studies (GWASs) with up to 100,000 participants and a TC meta-GWAS (nCase = 3,418, nControl = 292,703) to conduct proteome-wide Mendelian randomization (MR) and Bayesian colocalization analysis. Protein and gene expressions were validated in thyroid tissue. Through MR analysis, we identified 26 circulating proteins with a putative causal relationship with TCs, among which NANS protein passed multiple corrections (P BH = 3.28e-5, 0.05/1,525). These proteins were involved in amino acids and organic acid synthesis pathways. Colocalization analysis further identified six proteins associated with TCs (VCAM1, LGMN, NPTX1, PLEKHA7, TNFAIP3, and BMP1). Tissue validation confirmed BMP1, LGMN, and PLEKHA7's differential expression between normal and TC tissues. We found limited evidence for linking circulating proteins and the risk of TCs. Our study highlighted the contribution of proteins, particularly those involved in amino acid metabolism, to TCs.

Basement Membranes, Brittlestar Tendons, and Their Mechanical Adaptability

Basement membranes (BMs) are thin layers of extracellular matrix that separate epithelia, endothelia, muscle cells, and nerve cells from adjacent interstitial connective tissue. BMs are ubiquitous in almost all multicellular animals, and their composition is highly conserved across the Metazoa. There is increasing interest in the mechanical functioning of BMs, including the involvement of altered BM stiffness in development and pathology, particularly cancer metastasis, which can be facilitated by BM destabilization. Such BM weakening has been assumed to occur primarily through enzymatic degradation by matrix metalloproteinases. However, emerging evidence indicates that non-enzymatic mechanisms may also contribute. In brittlestars (Echinodermata, Ophiuroidea), the tendons linking the musculature to the endoskeleton consist of extensions of muscle cell BMs. During the process of brittlestar autotomy, in which arms are detached for the purpose of self-defense, muscles break away from the endoskeleton as a consequence of the rapid destabilization and rupture of their BM-derived tendons. This contribution provides a broad overview of current knowledge of the structural organization and biomechanics of non-echinoderm BMs, compares this with the equivalent information on brittlestar tendons, and discusses the possible relationship between the weakening phenomena exhibited by BMs and brittlestar tendons, and the potential translational value of the latter as a model system of BM destabilization.

Dual topologies of myotomal collagen XV and Tenascin C act in concert to guide and shape developing motor axons

During development, motor axons are guided toward muscle target by various extrinsic cues including extracellular matrix (ECM) proteins whose identities and cellular source remain poorly characterized. Here, using single-cell RNAseq of sorted GFP+ cells from smyhc1:gfp-injected zebrafish embryos, we unravel the slow muscle progenitors (SMP) pseudotemporal trajectory at the single-cell level and show that differentiating SMPs are a major source of ECM proteins. The SMP core-matrisome was characterized and computationally predicted to form a basement membrane-like structure tailored for motor axon guidance, including basement membrane-associated ECM proteins, as collagen XV-B, one of the earliest core-matrisome gene transcribed in differentiating SMPs and the glycoprotein Tenascin C. To investigate how contact-mediated guidance cues are organized along the motor path to exert their function in vivo, we used microscopy-based methods to analyze and quantify motor axon navigation in tnc and col15a1b knock-out fish. We show that motor axon shape and growth rely on the timely expression of the attractive cue Collagen XV-B that locally provides axons with a permissive soft microenvironment and separately organizes the repulsive cue Tenascin C into a unique functional dual topology. Importantly, bioprinted micropatterns that mimic this in vivo ECM topology were sufficient to drive directional motor axon growth. Our study offers evidence that not only the composition of ECM cues but their topology critically influences motor axon navigation in vertebrates with potential applications in regenerative medicine for peripheral nerve injury as regenerating nerves follow their original path.

Increased glycolysis and cellular crosstalk in eosinophilic chronic rhinosinusitis with nasal polyps

Introduction

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the sinonasal mucosa with distinct endotypes including type 2 (T2) high eosinophilic CRS with nasal polyps (eCRSwNP), T2 low non-eosinophilic CRS with nasal polyps (neCRSwNP), and CRS without nasal polyps (CRSsNP).

Methods

Given the heterogeneity of disease, we hypothesized that assessment of single cell RNA sequencing (scRNA-seq) across this spectrum of disease would reveal connections between infiltrating and activated immune cells and the epithelial and stromal populations that reside in sinonasal tissue.

Results

Here we find increased expression of genes encoding glycolytic enzymes in epithelial cells (EpCs), stromal cells, and memory T-cell subsets from patients with eCRSwNP, as compared to healthy controls. In basal EpCs, this is associated with a program of cell motility and Rho GTPase effector expression. Across both stromal and immune subsets, glycolytic programming was associated with extracellular matrix interactions, proteoglycan generation, and collagen formation. Furthermore, we report increased cell-cell interactions between EpCs and stromal/immune cells in eCRSwNP compared to healthy control tissue, and we nominate candidate receptor-ligand pairs that may drive tissue remodeling.

Discussion

These findings support a role for glycolytic reprograming in T2-elicited tissue remodeling and implicate increased cellular crosstalk in eCRSwNP.

Single-cell RNA sequencing of submandibular gland reveals collagen type XV-positive fibroblasts as a disease-characterizing cell population of IgG4-related disease

OBJECTIVES

IgG4-related disease (IgG4-RD) is a systemic autoimmune disease with an unknown etiology, affecting single/multiple organ(s). Pathological findings include the infiltration of IgG4-producing plasma cells, obliterative phlebitis, and storiform fibrosis. Although immunological studies have shed light on the dysregulation of lymphocytes in IgG4-RD pathogenesis, the role of non-immune cells remains unclear. This study aimed to investigate the demographics and characteristics of non-immune cells in IgG4-RD and explore potential biomarkers derived from non-immune cells in the sera.

METHODS

We conducted single-cell RNA sequence (scRNA-seq) on non-immune cells isolated from submandibular glands of IgG4-RD patients. We focused on fibroblasts expressing collagen type XV and confirmed the presence of those fibroblasts using immunohistochemistry. Additionally, we measured the levels of collagen type XV in the sera of IgG4-RD patients.

RESULTS

The scRNA-seq analysis revealed several distinct clusters consisting of fibroblasts, endothelial cells, ductal cells, and muscle cells. Differential gene expression analysis showed upregulation of COL15A1 in IgG4-RD fibroblasts compared to control subjects. Notably, COL15A1-positive fibroblasts exhibited a distinct transcriptome compared to COL15A1-negative counterparts. Immunohistochemical analysis confirmed a significant presence of collagen type XV-positive fibroblasts in IgG4-RD patients. Furthermore, immune-suppressive therapy in active IgG4-RD patients resulted in decreased serum levels of collagen type XV.

CONCLUSIONS

Our findings suggest that collagen type XV-producing fibroblasts may represent a disease-characterizing non-immune cell population in IgG4-RD and hold potential as a disease-monitoring marker.

Fine-scale mapping of chromosome 9q22.33 identifies candidate causal variant in ovarian cancer

Ovarian cancer is a complex polygenic disease in which genetic factors play a significant role in disease etiology. A genome-wide association study (GWAS) identified a novel variant on chromosome 9q22.33 as a susceptibility locus for epithelial ovarian cancer (EOC) in the Han Chinese population. However, the underlying mechanism of this genomic region remained unknown. In this study, we conducted a fine-mapping analysis of 130 kb regions, including 1,039 variants in 200 healthy women. Ten variants were selected to evaluate the association with EOC risk in 1,099 EOC cases and 1,591 controls. We identified two variants that were significantly associated with ovarian cancer risk (rs7027650, P = 1.91 × 10-7; rs1889268, P = 3.71 × 10-2). Expression quantitative trait locus (eQTL) analysis found that rs7027650 was significantly correlated with COL15A1 gene expression (P = 0.009). The Luciferase reporter gene assay confirmed that rs7027650 could interact with the promoter region of COL15A1, reducing its activity. An electrophoretic mobility shift assay (EMSA) showed the allele-specific binding capacity of rs7027650. These findings revealed that rs7027650 could be a potential causal variant at 9q22.33 region and may regulate the expression level of COL15A1. This study offered insight into the molecular mechanism behind a potential causal variant that affects the risk of ovarian cancer.

miR-9 promotes canine endothelial-like cell migration by targeting COL15A1

BACKGROUND

Endothelial cell migration is the initial stage of angiogenesis. In previous studies, miR-9 has been found to regulate angiogenesis and cell migration in human medicine.

OBJECTIVES

This study aimed to reveal the regulatory effect of miR-9 on canine endothelial cell migration.

METHODS

Embryonic canine ventricle myocardium tissues were collected and induced to differentiate into endothelial-like cells (ELCs). A transwell and invasion assay were used to evaluate the impact of miR-9 on the migration capacity of ELCs, after which a luciferase reporter assay, western blotting, RNA sequencing and reverse transcription-polymerase chain reaction were conducted to explore the regulatory mechanism.

RESULTS

Our results showed that we successfully induced the primary cells derived from canine cardiac embryo tissues into ELCs. MiR-9 also promoted the migration and invasion of canine ELCs, and inhibited the expression of collagen XV, an angiogenic inhibitor, at the translational level by targeting the 3' untranslated region of COL15A1 gene. Furthermore, RNA sequencing showed that overexpression of miR-9 impacted several signalling pathways and eight genes involved in angiogenesis and cell migration in canine ELCs.

CONCLUSIONS

These findings suggest that miR-9 enhances the migration of canine ELCs and may serve as a potential diagnostic and therapeutic target for canine diseases involved in endothelial cells migration and angiogenesis, but more further studies are needed.

New insights into the natural history of bronchopulmonary dysplasia from proteomics and multiplexed immunohistochemistry

Bronchopulmonary dysplasia (BPD) is a disease of prematurity related to the arrest of normal lung development. The objective of this study was to better understand how proteome modulation and cell-type shifts are noted in BPD pathology. Pediatric human donors aged 1-3 yr were classified based on history of prematurity and histopathology consistent with "healed" BPD (hBPD, n = 3) and "established" BPD (eBPD, n = 3) compared with respective full-term born (n = 6) age-matched term controls. Proteins were quantified by tandem mass spectroscopy with selected Western blot validations. Multiplexed immunofluorescence (MxIF) microscopy was performed on lung sections to enumerate cell types. Protein abundances and MxIF cell frequencies were compared among groups using ANOVA. Cell type and ontology enrichment were performed using an in-house tool and/or EnrichR. Proteomics detected 5,746 unique proteins, 186 upregulated and 534 downregulated, in eBPD versus control with fewer proteins differentially abundant in hBPD as compared with age-matched term controls. Cell-type enrichment suggested a loss of alveolar type I, alveolar type II, endothelial/capillary, and lymphatics, and an increase in smooth muscle and fibroblasts consistent with MxIF. Histochemistry and Western analysis also supported predictions of upregulated ferroptosis in eBPD versus control. Finally, several extracellular matrix components mapping to angiogenesis signaling pathways were altered in eBPD. Despite clear parsing by protein abundance, comparative MxIF analysis confirms phenotypic variability in BPD. This work provides the first demonstration of tandem mass spectrometry and multiplexed molecular analysis of human lung tissue for critical elucidation of BPD trajectory-defining factors into early childhood.NEW & NOTEWORTHY We provide new insights into the natural history of bronchopulmonary dysplasia in donor human lungs after the neonatal intensive care unit hospitalization. This study provides new insights into how the proteome and histopathology of BPD changes in early childhood, uncovering novel pathways for future study.

Vascular Contribution to Lung Repair and Fibrosis

Lungs are constantly exposed to environmental perturbations and therefore have remarkable capacity to regenerate in response to injury. Sustained lung injuries, aging, and increased genomic instability, however, make lungs particularly susceptible to disrepair and fibrosis. Pulmonary fibrosis constitutes a major cause of morbidity and is often relentlessly progressive, leading to death from respiratory failure. The pulmonary vasculature, which is critical for gas exchanges and plays a key role during lung development, repair, and regeneration, becomes aberrantly remodeled in patients with progressive pulmonary fibrosis. Although capillary rarefaction and increased vascular permeability are recognized as distinctive features of fibrotic lungs, the role of vasculature dysfunction in the pathogenesis of pulmonary fibrosis has only recently emerged as an important contributor to the progression of this disease. This review summarizes current findings related to lung vascular repair and regeneration and provides recent insights into the vascular abnormalities associated with the development of persistent lung fibrosis.

Collagens Regulating Adipose Tissue Formation and Functions

The globally increasing prevalence of obesity is associated with the development of metabolic diseases such as type 2 diabetes, dyslipidemia, and fatty liver. Excess adipose tissue (AT) often leads to its malfunction and to a systemic metabolic dysfunction because, in addition to storing lipids, AT is an active endocrine system. Adipocytes are embedded in a unique extracellular matrix (ECM), which provides structural support to the cells as well as participating in the regulation of their functions, such as proliferation and differentiation. Adipocytes have a thin pericellular layer of a specialized ECM, referred to as the basement membrane (BM), which is an important functional unit that lies between cells and tissue stroma. Collagens form a major group of proteins in the ECM, and some of them, especially the BM-associated collagens, support AT functions and participate in the regulation of adipocyte differentiation. In pathological conditions such as obesity, AT often proceeds to fibrosis, characterized by the accumulation of large collagen bundles, which disturbs the natural functions of the AT. In this review, we summarize the current knowledge on the vertebrate collagens that are important for AT development and function and include basic information on some other important ECM components, principally fibronectin, of the AT. We also briefly discuss the function of AT collagens in certain metabolic diseases in which they have been shown to play central roles.

Novel Biomarkers of Health and Degeneration in Human Intervertebral Discs: In-depth Proteomic Analysis of Collagen Framework of Fetal, Healthy, Scoliotic, Degenerate, and Herniated Discs

STUDY DESIGN

Profiling proteins expressed in the nucleus pulposus (NP) of intervertebral discs (IVDs) in five different biological states.

PURPOSE

To evaluate the molecular complexity of the collagen (COL) framework and its role in the health and disease of human IVDs.

OVERVIEW OF LITERATURE

Changes in COL composition have been linked to degenerative disk disease (DDD). Despite the fact that humans have 28 different types of COLs, most of the literature focuses solely on COL-1 and COL-2. This study used high-end proteomic technology to examine the entire COL composition of the human IVD across fetal (developmental-FD), normal (healthy-ND), scoliotic (early degeneration-SD), herniated (degenerate-DH), and degenerated (DD) disk phenotypes.

METHODS

Forty NP tissues were snap-frozen in liquid nitrogen (-196°C) immediately before being subjected to proteomic and bioinformatic analyses from five different disk phenotypes (eight each).

RESULTS

Tandem mass spectrometric analysis revealed a total of 1,050 proteins in FDs, 1,809 in ND, 1,487 in SD, 1,859 in DH, and 1,538 in the DD group. Of 28 major collagens reported in the human body, this study identified 24 different collagens with 34 subtypes in NP. Fibril-forming collagens (COL-1, 2, and 11A1) and fibril-associated collagens with interrupted triple helices (COL-9A1, 12A1, and 14A1) were abundantly expressed in FDs, representing their role in the development of NP. Multiplexin (COL-15), a hybrid proteoglycan-collagen molecule, was discovered only in FDs. Degeneration was associated with COL2A1 downregulation and COL-10A1 upregulation.

CONCLUSIONS

COL10 was discovered to be a new biomarker for disk degeneration. Besides COL-1 and 2, other important COLs (6, 9, 11, 12, 14, 15) with anabolic potential and abundant expression in the fetal phenotype could be investigated for tissue engineering and novel DDD therapy.

Context Matters: Response Heterogeneity to Collagen-Targeting Approaches in Desmoplastic Cancers

Simple Summary

A common feature of tumor types such as breast cancer, prostate cancer, pancreatic cancer, and soft-tissue sarcoma is the deposition of collagen-rich tissue called desmoplasia. However, efforts to control tumor growth by disrupting desmoplasia, collectively known as “collagen-targeting approaches”, have had mixed and contradictory results, sometimes even within the same cancer type. We believe that this phenomenon may be due—at least partially—to the fact that “collagen” is not a single molecule, but rather a diverse molecular family composed of 28 unique collagen types. Therefore, in this review, we discuss the diversity of collagen molecules in normal and cancer tissue, and explore how collagen heterogeneity relates to the mixed efficacy of collagen-targeting approaches for cancer therapy.

Abstract

The deposition of collagen-rich desmoplastic tissue is a well-documented feature of the solid tumor microenvironment (TME). However, efforts to target the desmoplastic extracellular matrix (ECM) en masse, or collagen molecules more specifically, have been met with mixed and sometimes paradoxical results. In this review, we posit that these discrepancies are due—at least in part—to the incredible diversity of the collagen superfamily. Specifically, whereas studies of “collagen-targeting” approaches frequently refer to “collagen” as a single molecule or relatively homogeneous molecular family, 28 individual collagens have been identified in mammalian tissues, each with a unique structure, supramolecular assembly pattern, tissue distribution, and/or function. Moreover, some collagen species have been shown to exert both pro- and anti-neoplastic effects in the desmoplastic TME, even within the same cancer type. Therefore, herein, we describe the diversity of the collagen family in normal tissues and highlight the context-specific roles of individual collagen molecules in desmoplastic tumors. We further discuss how this heterogeneity relates to the variable efficacy of “collagen-targeting” strategies in this setting and provide guidance for future directions in the field.

Individualized discovery of rare cancer drivers in global network context

Late advances in genome sequencing expanded the space of known cancer driver genes several-fold. However, most of this surge was based on computational analysis of somatic mutation frequencies and/or their impact on the protein function. On the contrary, experimental research necessarily accounted for functional context of mutations interacting with other genes and conferring cancer phenotypes. Eventually, just such results become ‘hard currency’ of cancer biology. The new method, NEAdriver employs knowledge accumulated thus far in the form of global interaction network and functionally annotated pathways in order to recover known and predict novel driver genes. The driver discovery was individualized by accounting for mutations’ co-occurrence in each tumour genome – as an alternative to summarizing information over the whole cancer patient cohorts. For each somatic genome change, probabilistic estimates from two lanes of network analysis were combined into joint likelihoods of being a driver. Thus, ability to detect previously unnoticed candidate driver events emerged from combining individual genomic context with network perspective. The procedure was applied to 10 largest cancer cohorts followed by evaluating error rates against previous cancer gene sets. The discovered driver combinations were shown to be informative on cancer outcome. This revealed driver genes with individually sparse mutation patterns that would not be detectable by other computational methods and related to cancer biology domains poorly covered by previous analyses. In particular, recurrent mutations of collagen, laminin, and integrin genes were observed in the adenocarcinoma and glioblastoma cancers. Considering constellation patterns of candidate drivers in individual cancer genomes opens a novel avenue for personalized cancer medicine.

The Proteome of Antibody-Mediated Rejection: From Glomerulitis to Transplant Glomerulopathy

Antibody-mediated rejection (ABMR) is the leading cause of allograft failure in kidney transplantation. Its histological hallmark is represented by lesions of glomerulitis i.e., inflammatory cells within glomeruli. Current therapies for ABMR fail to prevent chronic allograft damage i.e., transplant glomerulopathy, leading to allograft loss. We used laser microdissection of glomeruli from formalin-fixed allograft biopsies combined with mass spectrometry-based proteomics to describe the proteome modification of 11 active and 10 chronic active ABMR cases compared to 8 stable graft controls. Of 1335 detected proteins, 77 were deregulated in glomerulitis compared to stable grafts, particularly involved in cellular stress mediated by interferons type I and II, leukocyte activation and microcirculation remodeling. Three proteins extracted from this protein profile, TYMP, WARS1 and GBP1, showed a consistent overexpression by immunohistochemistry in glomerular endothelial cells that may represent relevant markers of endothelial stress during active ABMR. In transplant glomerulopathy, 137 proteins were deregulated, which favor a complement-mediated mechanism, wound healing processes through coagulation activation and ultimately a remodeling of the glomerular extracellular matrix, as observed by light microscopy. This study brings novel information on glomerular proteomics of ABMR in kidney transplantation, and highlights potential targets of diagnostic and therapeutic interest.

Mammary collagen is under reproductive control with implications for breast cancer

Mammographically-detected breast density impacts breast cancer risk and progression, and fibrillar collagen is a key component of breast density. However, physiologic factors influencing collagen production in the breast are poorly understood. In female rats, we analyzed gene expression of the most abundantly expressed mammary collagens and collagen-associated proteins across a pregnancy, lactation, and weaning cycle. We identified a triphasic pattern of collagen gene regulation and evidence for reproductive state-dependent composition. An initial phase of collagen deposition occurred during pregnancy, followed by an active phase of collagen suppression during lactation. The third phase of collagen regulation occurred during weaning-induced mammary gland involution, which was characterized by increased collagen deposition. Concomitant changes in collagen protein abundance were confirmed by Masson's trichrome staining, second harmonic generation (SHG) imaging, and mass spectrometry. We observed similar reproductive-state dependent collagen patterns in human breast tissue obtained from premenopausal women. SHG analysis also revealed structural variation in collagen across a reproductive cycle, with higher packing density and more collagen fibers arranged perpendicular to the mammary epithelium in the involuting rat mammary gland compared to nulliparous and lactating glands. Involution was also characterized by high expression of the collagen cross-linking enzyme lysyl oxidase, which was associated with increased levels of cross-linked collagen. Breast cancer relevance is suggested, as we found that breast cancer diagnosed in recently postpartum women displayed gene expression signatures of increased collagen deposition and crosslinking compared to breast cancers diagnosed in age-matched nulliparous women. Using publically available data sets, we found this involution-like, collagen gene signature correlated with poor progression-free survival in breast cancer patients overall and in younger women. In sum, these findings of physiologic collagen regulation in the normal mammary gland may provide insight into normal breast function, the etiology of breast density, and inform breast cancer risk and outcomes.

Collagen- and hyaluronic acid-based hydrogels and their biomedical applications

Hydrogels have been widely investigated in biomedical fields due to their similar physical and biochemical properties to the extracellular matrix (ECM). Collagen and hyaluronic acid (HA) are the main components of the ECM in many tissues. As a result, hydrogels prepared from collagen and HA hold inherent advantages in mimicking the structure and function of the native ECM. Numerous studies have focused on the development of collagen and HA hydrogels and their biomedical applications. In this extensive review, we provide a summary and analysis of the sources, features, and modifications of collagen and HA. Specifically, we highlight the fabrication, properties, and potential biomedical applications as well as promising commercialization of hydrogels based on these two natural polymers.

Stroma AReactive Invasion Front Areas (SARIFA) - a new prognostic biomarker in gastric cancer related to tumor-promoting adipocytes

Compared to other malignancies, there is a lack of easy-to-evaluate biomarkers for gastric cancer, which is associated with an adverse clinical outcome in many cases. Here, we present Stroma AReactive Invasion Front Areas (SARIFA) as a new histological prognostic marker. We defined SARIFA as the direct contact between a cluster of tumor glands/cells comprising at least five tumor cells and inconspicuous surrounding adipose tissue at the invasion front. A total of 480 adenocarcinomas of the stomach and the gastroesophageal junction from two different collections were classified according to SARIFA. To understand the potential underlying mechanisms, a transcriptome analysis was conducted using digital spatial profiling (DSP). It was found that 20% of the tumors were SARIFA-positive. Kappa values between the three pathologists were good in both collections: 0.74 and 0.78. Patients who presented SARIFA-positive tumors had a significantly lower overall survival in Collections A (median: 20.0 versus 44.0 months; p = 0.014, n = 160) and B (median: 15.0 versus 41.0 months; p < 0.0001, n = 320). SARIFA positivity emerged as a negative independent prognostic factor for overall survival (HR 1.638, 95% CI 1.153-2.326, p = 0.006). Using DSP, the most upregulated genes in SARIFA-positive cases were those associated with triglyceride catabolism and endogenous sterols. COL15A1, FABP2, and FABP4 were differentially expressed in positive cases. At the protein level, the expression of proteins related to lipid metabolism was confirmed. SARIFA combines low inter-observer variability, minimal effort, and high prognostic relevance, and is therefore an extremely promising biomarker related to tumor-promoting adipocytes in gastric cancer. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Deletion of Col15a1 Modulates the Tumour Extracellular Matrix and Leads to Increased Tumour Growth in the MMTV-PyMT Mouse Mammary Carcinoma Model

Basement membrane (BM) zone-associated collagen XV (ColXV) has been shown to suppress the malignancy of tumour cells, and its restin domain can inhibit angiogenesis. In human breast cancer, as well as in many other human carcinomas, ColXV is lost from the epithelial BM zone prior to tumour invasion. Here, we addressed the roles of ColXV in breast carcinogenesis using the transgenic MMTV-PyMT mouse mammary carcinoma model. We show here for the first time that the inactivation of Col15a1 in mice leads to changes in the fibrillar tumour matrix and to increased mammary tumour growth. ColXV is expressed by myoepithelial and endothelial cells in mammary tumours and is lost from the ductal BM along with the loss of the myoepithelial layer during cancer progression while persisting in blood vessels and capillaries, even in invasive tumours. However, despite the absence of anti-angiogenic restin domain, neovascularisation was reduced rather than increased in the ColXV-deficient mammary tumours compared to controls. We also show that, in robust tumour cell transplantation models or in a chemical-induced fibrosarcoma model, the inactivation of Col15a1 does not affect tumour growth or angiogenesis. In conclusion, our results support the proposed tumour suppressor function of ColXV in mammary carcinogenesis and reveal diverse roles of this collagen in different cancer types.

Collagen-based biomaterials for biomedical applications

Collagen is an insoluble fibrous protein that composes the extracellular matrix in animals. Although collagen has been used as a biomaterial since 1881, the properties and the complex structure of collagen are still extensive study subjects worldwide. In this article, several topics of importance for understanding collagen research are reviewed starting from its historical milestones, followed by the description of the collagen superfamily and its complex structures, with a focus on type I collagen. Subsequently, some of the superior properties of collagen-based biomaterials, such as biocompatibility, biodegradability, mechanical properties, and cell activities, are pinpointed. These properties make collagen applicable in biomedicine, such as wound healing, tissue engineering, surface coating of medical devices, and skin supplementation. Moreover, some antimicrobial strategies and the general host tissue responses regarding collagen as a biomaterial are presented. Finally, the current status and clinical application of the three-dimensional (3D) printing techniques for the fabrication of collagen-based scaffolds and the reconstruction of the human heart's constituents, such as capillary structures or even the entire organ, are discussed. Besides, an overall outlook for the future of this unique biomaterial is provided.

A guide to the composition and functions of the extracellular matrix

Extracellular matrix (ECM) is a dynamic 3-dimensional network of macromolecules that provides structural support for the cells and tissues. Accumulated knowledge clearly demonstrated over the last decade that ECM plays key regulatory roles since it orchestrates cell signaling, functions, properties and morphology. Extracellularly secreted as well as cell-bound factors are among the major members of the ECM family. Proteins/glycoproteins, such as collagens, elastin, laminins and tenascins, proteoglycans and glycosaminoglycans, hyaluronan, and their cell receptors such as CD44 and integrins, responsible for cell adhesion, comprise a well-organized functional network with significant roles in health and disease. On the other hand, enzymes such as matrix metalloproteinases and specific glycosidases including heparanase and hyaluronidases contribute to matrix remodeling and affect human health. Several cell processes and functions, among them cell proliferation and survival, migration, differentiation, autophagy, angiogenesis, and immunity regulation are affected by certain matrix components. Structural alterations have been also well associated with disease progression. This guide on the composition and functions of the ECM gives a broad overview of the matrisome, the major ECM macromolecules, and their interaction networks within the ECM and with the cell surface, summarizes their main structural features and their roles in tissue organization and cell functions, and emphasizes the importance of specific ECM constituents in disease development and progression as well as the advances in molecular targeting of ECM to design new therapeutic strategies.

Blended Natural Support Materials-Collagen Based Hydrogels Used in Biomedicine

Due to their unique properties-the are biocompatible, easily accessible, and inexpensive with programmable properties-biopolymers are used in pharmaceutical and biomedical research, as well as in cosmetics and food. Collagen is one of the most-used biomaterials in biomedicine, being the most abundant protein in animals with a triple helices structure, biocompatible, biomimetic, biodegradable, and hemostatic. Its disadvantages are its poor mechanical and thermal properties and enzymatic degradation. In order to solve this problem and to use its benefits, collagen can be used blended with other biomaterials such as alginate, chitosan, and cellulose. The purpose of this review article is to offer a brief paper with updated information on blended collagen-based formulations and their potential application in biomedicine.

Physicochemical characterization and self-assembly of human amniotic membrane and umbilical cord collagen: A comparative study

The diverse application of collagen has created a need to discover renewable and economical sources with prevailing/improved physico-chemical properties. To address this scenario, the present study has extracted collagen from Human Amniotic Membrane (AM) and Umbilical cord, which are treated as medical waste and compared its physico-chemical properties. Collagen was extracted by pepsin solubilization using various salt concentrations (1 M, 2 M and 4 M). Umbilical Cord Collagen (UC) yield was 10% higher than Amniotic Membrane Collagen (AC). UC reported 58% higher sulphated glycosaminoglycan content than AC. Electrophoretic pattern of AC and UC in both disulphide bond reducing and non-reducing conditions showed bands corresponding to collagen type I, III, IV, V and XV. Collagen morphology was examined using SEM and the amino acid content was quantified by HPLC and LC-MS/MS. Triple helicity was confirmed by CD and FTIR spectra. Thermal transition temperature of AC and UC was found equivalent to animal collagen. Self-assembly, fibril morphology and spatial alignment was studied using AFM and DLS. Biocompatibility was analyzed using 3T3 fibroblast cells. In conclusion, UC with higher yield, presented with better physico-chemical, structural and biological properties than AC could serve as an efficient alternative to the existing animal collagen for diverse applications.