Matrix Biology Plus最新文献

{"title":"Designing collagens to shed light on the multi-scale structure–function mapping of matrix disorders","authors":"Sonal Gahlawat ,&nbsp;Vikas Nanda ,&nbsp;David I. Shreiber","doi":"10.1016/j.mbplus.2023.100139","DOIUrl":"10.1016/j.mbplus.2023.100139","url":null,"abstract":"<div><p>Collagens are the most abundant structural proteins in the extracellular matrix of animals and play crucial roles in maintaining the structural integrity and mechanical properties of tissues and organs while mediating important biological processes. Fibrillar collagens have a unique triple helix structure with a characteristic repeating sequence of (Gly-X-Y)_n. Variations within the repetitive sequence can cause misfolding of the triple helix, resulting in heritable connective tissue disorders. The most common variations are single-point missense mutations that lead to the substitution of a glycine residue with a bulkier amino acid (Gly → X). In this review, we will first discuss the importance of collagen’s triple helix structure and how single Gly substitutions can impact its folding, structure, secretion, assembly into higher-order structures, and biological functions. We will review the role of “designer collagens,” i.e., synthetic collagen-mimetic peptides and recombinant bacterial collagen as model systems to include Gly → X substitutions observed in collagen disorders and investigate their impact on structure and function utilizing <em>in vitro</em> studies. Lastly, we will explore how computational modeling of collagen peptides, especially molecular and steered molecular dynamics, has been instrumental in probing the effects of Gly substitutions on structure, receptor binding, and mechanical stability across multiple length scales.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"21 ","pages":"Article 100139"},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590028523000121/pdfft?md5=f665a8dedce3173e618017d91ffbebfd&pid=1-s2.0-S2590028523000121-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139017085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial gene expression in the adult rat patellar tendon","authors":"Danielle Steffen ,&nbsp;Michael Mienaltowski ,&nbsp;Keith Baar","doi":"10.1016/j.mbplus.2023.100138","DOIUrl":"https://doi.org/10.1016/j.mbplus.2023.100138","url":null,"abstract":"<div><p>Tendons are dense connective tissues with relatively few cells which makes studying the molecular profile of the tissue challenging. There is not a consensus on the spatial location of various cell types within a tendon, nor the accompanying transcriptional profile. In the present study, we used two male rat patellar tendon samples for sequencing-based spatial transcriptomics to determine the gene expression profile. We integrated our data with a mouse Achilles single cell dataset to predict the cell type composition of the patellar tendon as a function of location within the tissue. The spatial location of the predicated cell types suggested that there were two populations of tendon fibroblasts, one located in the tendon midsubstance, while the other localized with red blood cells, pericytes, and immune cells to the tendon peripheral connective tissue. Of the highest expressed spatially variable genes, there were multiple genes with known function in tendon: Col1a1, Col1a2, Dcn, Fmod, Sparc, and Comp. Further, a novel spatially regulated gene (AABR07000398.1) with no known function was identified. The spatial gene expression of tendon associated genes (Scx, Thbs4, Tnmd, Can, Bgn, Lum, Adamts2, Lox, Ppib, Col2a1, Col3a1, Col6a2) was also visualized. Both patellar tendon samples had similar expression patterns for all these genes. This dataset provides new spatial insights into gene expression in a healthy tendon.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"19 ","pages":"Article 100138"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259002852300011X/pdfft?md5=92f789b40475e66f6e1aa25a6e729868&pid=1-s2.0-S259002852300011X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138475136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Omentum-derived matrix enables the study of metastatic ovarian cancer and stromal cell functions in a physiologically relevant environment","authors":"Lisa J. Neilson ,&nbsp;Douglas Cartwright ,&nbsp;Maija Risteli ,&nbsp;Elina M. Jokinen ,&nbsp;Lynn McGarry ,&nbsp;Toni Sandvik ,&nbsp;Konstantina Nikolatou ,&nbsp;Kelly Hodge ,&nbsp;Samuel Atkinson ,&nbsp;Maria Vias ,&nbsp;Emily J. Kay ,&nbsp;James D. Brenton ,&nbsp;Leo M. Carlin ,&nbsp;David M. Bryant ,&nbsp;Tuula Salo ,&nbsp;Sara Zanivan","doi":"10.1016/j.mbplus.2023.100136","DOIUrl":"https://doi.org/10.1016/j.mbplus.2023.100136","url":null,"abstract":"<div><p>High-grade serous (HGS) ovarian cancer is the most lethal gynaecological disease in the world and metastases is a major cause. The omentum is the preferential metastatic site in HGS ovarian cancer patients and <em>in vitro</em> models that recapitulate the original environment of this organ at cellular and molecular level are being developed to study basic mechanisms that underpin this disease. The tumour extracellular matrix (ECM) plays active roles in HGS ovarian cancer pathology and response to therapy. However, most of the current <em>in vitro</em> models use matrices of animal origin and that do not recapitulate the complexity of the tumour ECM in patients.</p><p>Here, we have developed omentum gel (OmGel), a matrix made from tumour-associated omental tissue of HGS ovarian cancer patients that has unprecedented similarity to the ECM of HGS omental tumours and is simple to prepare. When used in 2D and 3D <em>in vitro</em> assays to assess cancer cell functions relevant to metastatic ovarian cancer, OmGel performs as well as or better than the widely use Matrigel and does not induce additional phenotypic changes to ovarian cancer cells. Surprisingly, OmGel promotes pronounced morphological changes in cancer associated fibroblasts (CAFs). These changes were associated with the upregulation of proteins that define subsets of CAFs in tumour patient samples, highlighting the importance of using clinically and physiologically relevant matrices for <em>in vitro</em> studies. Hence, OmGel provides a step forward to study the biology of HGS omental metastasis. Metastasis in the omentum are also typical of other cancer types, particularly gastric cancer, implying the relevance of OmGel to study the biology of other highly lethal cancers.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"19 ","pages":"Article 100136"},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590028523000091/pdfft?md5=db15a375c67dbdf83c9f1115a1abae05&pid=1-s2.0-S2590028523000091-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138439427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Urokinase-type plasminogen activator (uPA) regulates invasion and matrix remodelling in colorectal cancer","authors":"Auxtine Micalet ,&nbsp;Luke J. Tappouni ,&nbsp;Katarzyna Peszko ,&nbsp;Despoina Karagianni ,&nbsp;Ashley Lam ,&nbsp;John R. Counsell ,&nbsp;Sergio A. Quezada ,&nbsp;Emad Moeendarbary ,&nbsp;Umber Cheema","doi":"10.1016/j.mbplus.2023.100137","DOIUrl":"https://doi.org/10.1016/j.mbplus.2023.100137","url":null,"abstract":"<div><h3>Background</h3><p>Cancer cells remodel their local physical environment through processes of matrix reorganisation, deposition, stiffening and degradation. Urokinase-type plasminogen activator (uPA), which is encoded by the <em>PLAU</em> gene, is an extracellular proteolytic enzyme known to be involved in cancer progression and tumour microenvironment (TME) remodelling. Perturbing uPA therefore has a strong potential as a mechano-based cancer therapy. This work is a bioengineering investigation to validate whether 1) uPA is involved in matrix degradation and 2) preventing matrix degradation by targeting uPA can reduce cancer cell invasion and metastasis.</p></div><div><h3>Methods</h3><p>To this aim, we used an engineered 3D <em>in vitro</em> model, termed the tumouroid, that appropriately mimics the tumour’s native biophysical environment (3 kPa). A CRISPR-Cas9 mediated uPA knockout was performed to introduce a loss of function mutation in the gene coding sequence. Subsequently, to validate the translational potential of blocking uPA action, we tested a pharmacological inhibitor, UK-371,801. The changes in matrix stiffness were measured by atomic force microscopy (AFM). Invasion was quantified using images of the tumouroid, obtained after 21 days of culture.</p></div><div><h3>Results</h3><p>We showed that uPA is highly expressed in invasive breast and colorectal cancers, and these invasive cancer cells locally degrade their TME. <em>PLAU</em> (uPA) gene knock-out (KO) completely stopped matrix remodelling and significantly reduced cancer invasion. Many invasive cancer gene markers were also downregulated in the <em>PLAU</em> KO tumouroids. Pharmacological inhibition of uPA showed similarly promising results, where matrix degradation was reduced and so was the cancer invasion.</p></div><div><h3>Conclusion</h3><p>This work supports the role of uPA in matrix degradation. It demonstrates that the invasion of cancer cells was significantly reduced when enzymatic breakdown of the TME matrix was prevented. Collectively, this provides strong evidence of the effectiveness of targeting uPA as a mechano-based cancer therapy.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"19 ","pages":"Article 100137"},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590028523000108/pdfft?md5=47553b59807ff2b369969b99375d6266&pid=1-s2.0-S2590028523000108-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138412731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal expression and spatial distribution of the proteoglycan versican during cardiac fibrosis development","authors":"Athiramol Sasi ,&nbsp;Andreas Romaine ,&nbsp;Pugazendhi Murugan Erusappan ,&nbsp;Arne Olav Melleby ,&nbsp;Almira Hasic ,&nbsp;Christen Peder Dahl ,&nbsp;Kaspar Broch ,&nbsp;Vibeke Marie Almaas ,&nbsp;Rosa Doñate Puertas ,&nbsp;H. Llewelyn Roderick ,&nbsp;Ida Gjervold Lunde ,&nbsp;Ivar Sjaastad ,&nbsp;Maria Vistnes ,&nbsp;Geir Christensen","doi":"10.1016/j.mbplus.2023.100135","DOIUrl":"10.1016/j.mbplus.2023.100135","url":null,"abstract":"<div><p>Cardiac fibrosis is a central pathological feature in several cardiac diseases, but the underlying molecular players are insufficiently understood. The extracellular matrix proteoglycan versican is elevated in heart failure and suggested to be a target for treatment. However, the temporal expression and spatial distribution of versican and the versican cleavage fragment containing the neoepitope DPEAAE in cardiac fibrosis remains to be elucidated. In this study, we have examined versican during cardiac fibrosis development in a murine pressure overload model and in patients with cardiomyopathies. We found that versican, mainly the V1 isoform, was expressed immediately after induction of pressure overload, preceding collagen accumulation, and versican protein levels extended from the perivascular region into the cardiac interstitium. In addition, we found increased production of versican by collagen expressing fibroblasts, and that it was deposited extensively in the fibrotic extracellular matrix during pressure overload. In cardiac cell cultures, the expression of versican was induced by the pro-fibrotic transforming growth factor beta and mechanical stretch. Furthermore, we observed that the proteolytic cleavage of versican (DPEAAE fragment) increased in the late phase of fibrosis development during pressure overload. In patients with hypertrophic and dilated cardiomyopathies, we found elevated levels of versican and a positive correlation between versican and collagen mRNA in the heart, as well as increased cleavage of full-length protein. Taken together, the temporal expression profile and the spatial distribution of both the full-length versican and the DPEAAE fragment observed in this study indicates a role for versican in development of cardiac fibrosis.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"19 ","pages":"Article 100135"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259002852300008X/pdfft?md5=2f40143c76be0e607a9220491b8dfec2&pid=1-s2.0-S259002852300008X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135566416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visualization of basement membranes by a nidogen-based fluorescent reporter in mice","authors":"Sugiko Futaki ,&nbsp;Ayano Horimoto ,&nbsp;Chisei Shimono ,&nbsp;Naoko Norioka ,&nbsp;Yukimasa Taniguchi ,&nbsp;Hitomi Hamaoka ,&nbsp;Mari Kaneko ,&nbsp;Mayo Shigeta ,&nbsp;Takaya Abe ,&nbsp;Kiyotoshi Sekiguchi ,&nbsp;Yoichi Kondo","doi":"10.1016/j.mbplus.2023.100133","DOIUrl":"10.1016/j.mbplus.2023.100133","url":null,"abstract":"<div><p>Basement membranes (BMs) are thin, sheet-like extracellular structures that cover the basal side of epithelial and endothelial tissues and provide structural and functional support to adjacent cell layers. The molecular structure of BMs is a fine meshwork that incorporates specialized extracellular matrix proteins. Recently, live visualization of BMs in invertebrates demonstrated that their structure is flexible and dynamically rearranged during cell differentiation and organogenesis. However, the BM dynamics in mammalian tissues remain to be elucidated. We developed a mammalian BM imaging probe based on nidogen-1, a major BM-specific protein. Recombinant human nidogen-1 fused with an enhanced green fluorescent protein (Nid1-EGFP) retains its ability to bind to other BM proteins, such as laminin, type IV collagen, and perlecan, in a solid-phase binding assay. When added to the culture medium of embryoid bodies derived from mouse ES cells, recombinant Nid1-EGFP accumulated in the BM zone of embryoid bodies, and BMs were visualized <em>in vitro</em>. For <em>in vivo</em> BM imaging, a knock-in reporter mouse line expressing human nidogen-1 fused to the red fluorescent protein mCherry (R26-CAG-Nid1-mCherry) was generated. R26-CAG-Nid1-mCherry showed fluorescently labeled BMs in early embryos and adult tissues, such as the epidermis, intestine, and skeletal muscles, whereas BM fluorescence was unclear in several other tissues, such as the lung and heart. In the retina, Nid1-mCherry fluorescence visualized the BMs of vascular endothelium and pericytes. In the developing retina, Nid1-mCherry fluorescence labeled the BM of the major central vessels; however, the BM fluorescence were hardly observed in the peripheral growing tips of the vascular network, despite the presence of endothelial BM. Time-lapse observation of the retinal vascular BM after photobleaching revealed gradual recovery of Nid1-mCherry fluorescence, suggesting the turnover of BM components in developing retinal blood vessels. To the best of our knowledge, this is the first demonstration of <em>in vivo</em> BM imaging using a genetically engineered mammalian model. Although R26-CAG-Nid1-mCherry has some limitations as an <em>in vivo</em> BM imaging model, it has potential applications in the study of BM dynamics during mammalian embryogenesis, tissue regeneration, and pathogenesis.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"18 ","pages":"Article 100133"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10149278/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9773433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole organism profiling of the Timp gene family","authors":"David Peeney ,&nbsp;Yu Fan ,&nbsp;Sadeechya Gurung ,&nbsp;Carolyn Lazaroff ,&nbsp;Shashikala Ratnayake ,&nbsp;Andrew Warner ,&nbsp;Baktiar Karim ,&nbsp;Daoud Meerzaman ,&nbsp;William G. Stetler-Stevenson","doi":"10.1016/j.mbplus.2023.100132","DOIUrl":"10.1016/j.mbplus.2023.100132","url":null,"abstract":"<div><p>Tissue inhibitor of metalloproteinases (TIMPs/Timps) are an endogenous family of widely expressed matrisome-associated proteins that were initially identified as inhibitors of matrix metalloproteinase activity (Metzincin family proteases). Consequently, TIMPs are often considered simply as protease inhibitors by many investigators. However, an evolving list of new metalloproteinase-independent functions for TIMP family members suggests that this concept is outdated. These novel TIMP functions include direct agonism/antagonism of multiple transmembrane receptors, as well as functional interactions with matrisome targets. While the family was fully identified over two decades ago, there has yet to be an in-depth study describing the expression of TIMPs in normal tissues of adult mammals. An understanding of the tissues and cell-types that express TIMPs 1 through 4, in both normal and disease states are important to contextualize the growing functional capabilities of TIMP proteins, which are often dismissed as non-canonical. Using publicly available single cell RNA sequencing data from the Tabula Muris Consortium, we analyzed approximately 100,000 murine cells across eighteen tissues from non-diseased organs, representing seventy-three annotated cell types, to define the diversity in Timp gene expression across healthy tissues. We describe the unique expression profiles across tissues and organ-specific cell types that all four Timp genes display. Within annotated cell-types, we identify clear and discrete cluster-specific patterns of Timp expression, particularly in cells of stromal and endothelial origins. RNA in-situ hybridization across four organs expands on the scRNA sequencing analysis, revealing novel compartments associated with individual Timp expression. These analyses emphasize a need for specific studies investigating the functional significance of Timp expression in the identified tissues and cell sub-types. This understanding of the tissues, specific cell types and microenvironment conditions in which Timp genes are expressed adds important physiological context to the growing array of novel functions for TIMP proteins.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"18 ","pages":"Article 100132"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10121480/pdf/main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9743704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single collagen fibrils isolated from high stress and low stress tendons show differing susceptibility to enzymatic degradation by the interstitial collagenase matrix metalloproteinase-1 (MMP-1)","authors":"Kelsey Y. Gsell ,&nbsp;Samuel P. Veres ,&nbsp;Laurent Kreplak","doi":"10.1016/j.mbplus.2023.100129","DOIUrl":"10.1016/j.mbplus.2023.100129","url":null,"abstract":"<div><p>Bovine forelimb flexor and extensor tendons serve as a model for examining high stress, energy storing and low stress, positional tendons, respectively. Previous research has shown structural differences between the collagen fibrils of these tissues. The nanoscale collagen fibrils of flexor tendons are smaller in size, more heavily crosslinked, and respond differently to mechanical loading. Meanwhile, energy storing tendons undergo less collagen turnover compared to positional tendons and are more commonly injured. These observations raise the question of whether collagen fibril structure influences the collagen degradation processes necessary for remodelling. Atomic force microscopy was used to image dry collagen fibrils before and after 5-hour exposure to matrix metalloproteinase-1 (MMP-1) to detect changes in fibril size. Collagen fibrils from three tissue types were studied: bovine superficial digital flexor tendons, matched-pair bovine lateral digital extensor tendons, and rat tail tendons. Compared to control fibrils exposed only to buffer, a significant decrease in fibril cross-sectional area (CSA) following MMP-1 exposure was observed for bovine extensor and rat tail fibrils, with larger fibrils experiencing a greater magnitude of CSA decrease in both fibril types. Fibrils from bovine flexor tendons, on the other hand, showed no decrease in CSA when exposed to MMP-1. The result did not appear to be linked to the small size of flexor fibrils, as equivalently sized extensor fibrils were readily degraded by the enzyme. Increased proteolytic resistance of collagen fibrils from high stress tendons may help to explain the longevity of collagen within these tissues <em>in vivo</em>.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"18 ","pages":"Article 100129"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10006499/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9465323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The extracellular matrix of dystrophic mouse diaphragm accounts for the majority of its passive stiffness and is resistant to collagenase digestion","authors":"Ross P. Wohlgemuth ,&nbsp;Ryan M. Feitzinger ,&nbsp;Kyle E. Henricson ,&nbsp;Daryl T. Dinh ,&nbsp;Sarah E. Brashear ,&nbsp;Lucas R. Smith","doi":"10.1016/j.mbplus.2023.100131","DOIUrl":"10.1016/j.mbplus.2023.100131","url":null,"abstract":"<div><p>The healthy skeletal muscle extracellular matrix (ECM) has several functions including providing structural integrity to myofibers, enabling lateral force transmission, and contributing to overall passive mechanical properties. In diseases such as Duchenne Muscular dystrophy, there is accumulation of ECM materials, primarily collagen, which results in fibrosis. Previous studies have shown that fibrotic muscle is often stiffer than healthy muscle, in part due to the increased number and altered architecture of collagen fibers within the ECM. This would imply that the fibrotic matrix is stiffer than the healthy matrix. However, while previous studies have attempted to quantify the extracellular contribution to passive stiffness in muscle, the outcomes are dependent on the type of method used. Thus, the goals of this study were to compare the stiffness of healthy and fibrotic muscle ECM and to demonstrate the efficacy of two methods for quantifying extracellular-based stiffness in muscle, namely decellularization and collagenase digestion. These methods have been demonstrated to remove the muscle fibers or ablate collagen fiber integrity, respectively, while maintaining the contents of the extracellular matrix. Using these methods in conjunction with mechanical testing on wildtype and D2.<em>mdx</em> mice, we found that a majority of passive stiffness in the diaphragm is dependent on the ECM, and the D2.<em>mdx</em> diaphragm ECM is resistant to digestion by bacterial collagenase. We propose that this resistance is due to the increased collagen cross-links and collagen packing density in the ECM of the D2.<em>mdx</em> diaphragm. Taken altogether, while we did not find increased stiffness of the fibrotic ECM, we did observe that the D2.<em>mdx</em> diaphragm conveyed resistance against collagenase digestion. These findings demonstrate how different methods for measuring ECM-based stiffness each have their own limitations and can produce different results.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"18 ","pages":"Article 100131"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/9b/47/main.PMC10036937.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9198921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Presence of type IIB procollagen in mouse articular cartilage and growth plate is revealed by immuno-histochemical analysis with a novel specific antibody","authors":"Emeline Perrier-Groult,&nbsp;Shérine Moustaghfir,&nbsp;Marielle Pasdeloup,&nbsp;Jean-Daniel Malcor,&nbsp;Jérôme Lafont,&nbsp;Frédéric Mallein-Gerin","doi":"10.1016/j.mbplus.2023.100130","DOIUrl":"10.1016/j.mbplus.2023.100130","url":null,"abstract":"<div><p>Type II collagen is the major fibrillar collagen in cartilage. It is synthesized in the form of precursors (procollagens) containing N- and C-terminal propeptides. The two main isoforms of type II procollagen protein are type IIA and type IIB procollagens, generated in a developmentally regulated manner by differential splicing of the primary gene transcript. Isoform IIA contains exon 2 and is produced mainly by chondroprogenitor cells while isoform IIB lacks exon 2 and is produced by differentiated chondrocytes. Thus, expression of IIA and IIB isoforms are reliable markers for identifying the differentiation status of chondrocytes but their biological function in the context of skeletal development is still not yet fully understood. Specific antibodies against IIA and IIB procollagen isoforms are already available. In this study, a synthetic peptide spanning the junction between exon 1 and exon 3 of the murine sequence was used as an immunogen to generate a novel rabbit polyclonal antibody directed against procollagen IIB. Characterization of this antibody by Western-blotting analysis of murine cartilage extracts and ELISA tests demonstrated its specificity to the type IIB isoform. Furthermore, by immunohistochemical studies, this antibody allowed the detection of procollagen IIB in embryonic cartilage as well as in articular cartilage and growth plate of young adult mice. Interestingly, this is the first antibody that has allowed the detection of procollagen IIB at both the intra- and extracellular level. This antibody therefore represents an interesting new tool for monitoring the spatial and temporal distribution of IIB isoforms in skeletal tissues of mouse models and for tracking the trafficking and processing of type IIB procollagen.</p></div>","PeriodicalId":52317,"journal":{"name":"Matrix Biology Plus","volume":"18 ","pages":"Article 100130"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/7f/10/main.PMC10024168.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9153829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}