Proteoglycan form and function: A comprehensive nomenclature of proteoglycans

The Brain and Spinal Microvasculature in Normal Aging

Changes in the brain and spinal cord microvasculature during normal aging contribute to the "sensitive" nature of aged central nervous system tissue to ischemic insults. In this review, we will examine alterations in the central nervous system microvasculature during normal aging, which we define as aging without a dominant pathology such as neurodegenerative processes, vascular injury or disease, or trauma. We will also discuss newer technologies to improve the study of central nervous system microvascular structure and function. Microvasculature within the brain and spinal cord will be discussed separately as anatomy and physiology differ between these compartments. Lastly, we will identify critical areas for future studies as well as key unanswered questions.

Matrix stiffness, endothelial dysfunction and atherosclerosis

Atherosclerosis (AS) is the leading cause of the human cardiovascular diseases (CVDs). Endothelial dysfunction promotes the monocytes infiltration and inflammation that participate fundamentally in atherogenesis. Endothelial cells (EC) have been recognized as mechanosensitive cells and have different responses to distinct mechanical stimuli. Emerging evidence shows matrix stiffness-mediated EC dysfunction plays a vital role in vascular disease, but the underlying mechanisms are not yet completely understood. This article aims to summarize the effect of matrix stiffness on the pro-atherosclerotic characteristics of EC including morphology, rigidity, biological behavior and function as well as the related mechanical signal. The review also discusses and compares the contribution of matrix stiffness-mediated phagocytosis of macrophages and EC to AS progression. These advances in our understanding of the relationship between matrix stiffness and EC dysfunction open the avenues to improve the prevention and treatment of now-ubiquitous atherosclerotic diseases.

The Contribution of Vascular Proteoglycans to Atherothrombosis: Clinical Implications

The vascular extracellular matrix (ECM) produced by endothelial and smooth muscle cells is composed of collagens and glycoproteins and plays an integral role in regulating the structure and function of the vascular wall. Alteration in the expression of these proteins is associated with endothelial dysfunction and has been implicated in the development and progression of atherosclerosis. The ECM composition of atherosclerotic plaques varies depending on plaque phenotype and vulnerability, with distinct differences observed between ruptured and erodes plaques. Moreover, the thrombi on the exposed ECM are diverse in structure and composition, suggesting that the best antithrombotic approach may differ depending on plaque phenotype. This review provides a comprehensive overview of the role of proteoglycans in atherogenesis and thrombosis. It discusses the differential expression of the proteoglycans in different plaque phenotypes and the potential impact on platelet function and thrombosis. Finally, the review highlights the importance of this concept in developing a targeted approach to antithrombotic treatments to improve clinical outcomes in cardiovascular disease.

Impaired angiogenesis in ageing: the central role of the extracellular matrix

Each step in angiogenesis is regulated by the extracellular matrix (ECM). Accumulating evidence indicates that ageing-related changes in the ECM driven by cellular senescence lead to a reduction in neovascularisation, reduced microvascular density, and an increased risk of tissue ischaemic injury. These changes can lead to health events that have major negative impacts on quality of life and place a significant financial burden on the healthcare system. Elucidating interactions between the ECM and cells during angiogenesis in the context of ageing is neceary to clarify the mechanisms underlying reduced angiogenesis in older adults. In this review, we summarize ageing-related changes in the composition, structure, and function of the ECM and their relevance for angiogenesis. Then, we explore in detail the mechanisms of interaction between the aged ECM and cells during impaired angiogenesis in the older population for the first time, discussing diseases caused by restricted angiogenesis. We also outline several novel pro-angiogenic therapeutic strategies targeting the ECM that can provide new insights into the choice of appropriate treatments for a variety of age-related diseases. Based on the knowledge gathered from recent reports and journal articles, we provide a better understanding of the mechanisms underlying impaired angiogenesis with age and contribute to the development of effective treatments that will enhance quality of life.

The Landscape of Small Leucine-Rich Proteoglycan Impact on Cancer Pathogenesis with a Focus on Biglycan and Lumican

Cancer development is a multifactorial procedure that involves changes in the cell microenvironment and specific modulations in cell functions. A tumor microenvironment contains tumor cells, non-malignant cells, blood vessels, cells of the immune system, stromal cells, and the extracellular matrix (ECM). The small leucine-rich proteoglycans (SLRPs) are a family of nineteen proteoglycans, which are ubiquitously expressed among mammalian tissues and especially abundant in the ECM. SLRPs are divided into five canonical classes (classes I-III, containing fourteen members) and non-canonical classes (classes IV-V, including five members) based on their amino-acid structural sequence, chromosomal organization, and functional properties. Variations in both the protein core structure and glycosylation status lead to SLRP-specific interactions with cell membrane receptors, cytokines, growth factors, and structural ECM molecules. SLRPs have been implicated in the regulation of cancer growth, motility, and invasion, as well as in cancer-associated inflammation and autophagy, highlighting their crucial role in the processes of carcinogenesis. Except for the class I SLRP decorin, to which an anti-tumorigenic role has been attributed, other SLPRs' roles have not been fully clarified. This review will focus on the functions of the class I and II SLRP members biglycan and lumican, which are correlated to various aspects of cancer development.

The role of fibromodulin in inflammatory responses and diseases associated with inflammation

Inflammation is an immune response that the host organism eliminates threats from foreign objects or endogenous signals. It plays a key role in the progression, prognosis as well as therapy of diseases. Chronic inflammatory diseases have been regarded as the main cause of death worldwide at present, which greatly affect a vast number of individuals, producing economic and social burdens. Thus, developing drugs targeting inflammation has become necessary and attractive in the world. Currently, accumulating evidence suggests that small leucine-rich proteoglycans (SLRPs) exhibit essential roles in various inflammatory responses by acting as an anti-inflammatory or pro-inflammatory role in different scenarios of diseases. Of particular interest was a well-studied member, termed fibromodulin (FMOD), which has been largely explored in the role of inflammatory responses in inflammatory-related diseases. In this review, particular focus is given to the role of FMOD in inflammatory response including the relationship of FMOD with the complement system and immune cells, as well as the role of FMOD in the diseases associated with inflammation, such as skin wounding healing, osteoarthritis (OA), tendinopathy, atherosclerosis, and heart failure (HF). By conducting this review, we intend to gain insight into the role of FMOD in inflammation, which may open the way for the development of new anti-inflammation drugs in the scenarios of different inflammatory-related diseases.

Extracellular Matrix-Based and Electrospun Scaffolding Systems for Vaginal Reconstruction

Congenital vaginal anomalies and pelvic organ prolapse affect different age groups of women and both have significant negative impacts on patients' psychological well-being and quality of life. While surgical and non-surgical treatments are available for vaginal defects, their efficacy is limited, and they often result in long-term complications. Therefore, alternative treatment options are urgently needed. Fortunately, tissue-engineered scaffolds are promising new treatment modalities that provide an extracellular matrix (ECM)-like environment for vaginal cells to adhere, secrete ECM, and be remodeled by host cells. To this end, ECM-based scaffolds or the constructs that resemble ECM, generated by self-assembly, decellularization, or electrospinning techniques, have gained attention from both clinicians and researchers. These biomimetic scaffolds are highly similar to the native vaginal ECM and have great potential for clinical translation. This review article aims to discuss recent applications, challenges, and future perspectives of these scaffolds in vaginal reconstruction or repair strategies.

Strategic outline of interventions targeting extracellular matrix for promoting healthy longevity

The extracellular matrix (ECM), composed of interlinked proteins outside of cells, is an important component of the human body that helps maintain tissue architecture and cellular homeostasis. As people age, the ECM undergoes changes that can lead to age-related morbidity and mortality. Despite its importance, ECM aging remains understudied in the field of geroscience. In this review, we discuss the core concepts of ECM integrity, outline the age-related challenges and subsequent pathologies and diseases, summarize diagnostic methods detecting a faulty ECM, and provide strategies targeting ECM homeostasis. To conceptualize this, we built a technology research tree to hierarchically visualize possible research sequences for studying ECM aging. This strategic framework will hopefully facilitate the development of future research on interventions to restore ECM integrity, which could potentially lead to the development of new drugs or therapeutic interventions promoting health during aging.

Proteoglycans in Articular Cartilage and Their Contribution to Chondral Injury and Repair Mechanisms

Proteoglycans are vital components of the extracellular matrix in articular cartilage, providing biomechanical properties crucial for its proper functioning. They are key players in chondral diseases, specifically in the degradation of the extracellular matrix. Evaluating proteoglycan molecules can serve as a biomarker for joint degradation in osteoarthritis patients, as well as assessing the quality of repaired tissue following different treatment strategies for chondral injuries. Despite ongoing research, understanding osteoarthritis and cartilage repair remains unclear, making the identification of key molecules essential for early diagnosis and effective treatment. This review offers an overview of proteoglycans as primary molecules in articular cartilage. It describes the various types of proteoglycans present in both healthy and damaged cartilage, highlighting their roles. Additionally, the review emphasizes the importance of assessing proteoglycans to evaluate the quality of repaired articular tissue. It concludes by providing a visual and narrative description of aggrecan distribution and presence in healthy cartilage. Proteoglycans, such as aggrecan, biglycan, decorin, perlecan, and versican, significantly contribute to maintaining the health of articular cartilage and the cartilage repair process. Therefore, studying these proteoglycans is vital for early diagnosis, evaluating the quality of repaired cartilage, and assessing treatment effectiveness.

Glycocalyx-Sodium Interaction in Vascular Endothelium

The glycocalyx generally covers almost all cellular surfaces, where it participates in mediating cell-surface interactions with the extracellular matrix as well as with intracellular signaling molecules. The endothelial glycocalyx that covers the luminal surface mediates the interactions of endothelial cells with materials flowing in the circulating blood, including blood cells. Cardiovascular diseases (CVD) remain a major cause of morbidity and mortality around the world. The cardiovascular risk factors start by causing endothelial cell dysfunction associated with destruction or irregular maintenance of the glycocalyx, which may culminate into a full-blown cardiovascular disease. The endothelial glycocalyx plays a crucial role in shielding the cell from excessive exposure and absorption of excessive salt, which can potentially cause damage to the endothelial cells and underlying tissues of the blood vessels. So, in this mini review/commentary, we delineate and provide a concise summary of the various components of the glycocalyx, their interaction with salt, and subsequent involvement in the cardiovascular disease process. We also highlight the major components of the glycocalyx that could be used as disease biomarkers or as drug targets in the management of cardiovascular diseases.

Xylosyltransferase I mediates the synthesis of proteoglycans with long glycosaminoglycan chains and controls chondrocyte hypertrophy and collagen fibers organization of in the growth plate

Genetic mutations in the Xylt1 gene are associated with Desbuquois dysplasia type II syndrome characterized by sever prenatal and postnatal short stature. However, the specific role of XylT-I in the growth plate is not completely understood. Here, we show that XylT-I is expressed and critical for the synthesis of proteoglycans in resting and proliferative but not in hypertrophic chondrocytes in the growth plate. We found that loss of XylT-I induces hypertrophic phenotype-like of chondrocytes associated with reduced interterritorial matrix. Mechanistically, deletion of XylT-I impairs the synthesis of long glycosaminoglycan chains leading to the formation of proteoglycans with shorter glycosaminoglycan chains. Histological and Second Harmonic Generation microscopy analysis revealed that deletion of XylT-I accelerated chondrocyte maturation and prevents chondrocytes columnar organization and arrangement in parallel of collagen fibers in the growth plate, suggesting that XylT-I controls chondrocyte maturation and matrix organization. Intriguingly, loss of XylT-I induced at embryonic stage E18.5 the migration of progenitor cells from the perichondrium next to the groove of Ranvier into the central part of epiphysis of E18.5 embryos. These cells characterized by higher expression of glycosaminoglycans exhibit circular organization then undergo hypertrophy and death creating a circular structure at the secondary ossification center location. Our study revealed an uncovered role of XylT-I in the synthesis of proteoglycans and provides evidence that the structure of glycosaminoglycan chains of proteoglycans controls chondrocyte maturation and matrix organization.

Role of Syndecans in Ovarian Cancer: New Diagnostic and Prognostic Biomarkers and Potential Therapeutic Targets

Ovarian cancer (OC) is the eighth cancer both in prevalence and mortality in women and represents the deadliest female reproductive cancer. Due to generally vague symptoms, OC is frequently diagnosed only at a late and advanced stage, resulting in high mortality. The tumor extracellular matrix and cellular matrix receptors play a key role in the pathogenesis of tumor progression. Syndecans are a family of four transmembrane heparan sulfate proteoglycans (PG), including syndecan-1, -2, -3, and -4, which are dysregulated in a myriad of cancers, including OC. Many clinicopathological studies suggest that these proteins are promising diagnostic and prognostic biomarkers for OC. Furthermore, functions of the syndecan family in the regulation of cellular processes make it an interesting pharmacological target for anticancer therapies.

The Role of Extracellular Matrix (ECM) Adhesion Motifs in Functionalised Hydrogels

To create functional tissue engineering scaffolds, biomaterials should mimic the native extracellular matrix of the tissue to be regenerated. Simultaneously, the survival and functionality of stem cells should also be enhanced to promote tissue organisation and repair. Hydrogels, but in particular, peptide hydrogels, are an emerging class of biocompatible scaffolds which act as promising self-assembling biomaterials for tissue engineering and regenerative therapies, ranging from articular cartilage regeneration at joint defects, to regenerative spinal cord injury following trauma. To enhance hydrogel biocompatibility, it has become imperative to consider the native microenvironment of the site for regeneration, where the use of functionalised hydrogels with extracellular matrix adhesion motifs has become a novel, emerging theme. In this review, we will introduce hydrogels in the context of tissue engineering, provide insight into the complexity of the extracellular matrix, investigate specific adhesion motifs that have been used to generate functionalised hydrogels and outline their potential applications in a regenerative medicine setting. It is anticipated that by conducting this review, we will provide greater insight into functionalised hydrogels, which may help translate their use towards therapeutic roles.

Deficiency of Fam20b-Catalyzed Glycosaminoglycan Chain Synthesis in Neural Crest Leads to Cleft Palate

Cleft palate is one of the most common birth defects. Previous studies revealed that multiple factors, including impaired intracellular or intercellular signals, and incoordination of oral organs led to cleft palate, but were little concerned about the contribution of the extracellular matrix (ECM) during palatogenesis. Proteoglycans (PGs) are one of the important macromolecules in the ECM. They exert biological functions through one or more glycosaminoglycan (GAG) chains attached to core proteins. The family with sequence similarity 20 member b (Fam20b) are newly identified kinase-phosphorylating xylose residues that promote the correct assembly of the tetrasaccharide linkage region by creating a premise for GAG chain elongation. In this study, we explored the function of GAG chains in palate development through Wnt1-Cre; Fam20b^f/f mice, which exhibited complete cleft palate, malformed tongue, and micrognathia. In contrast, Osr2-Cre; Fam20b^f/f mice, in which Fam20b was deleted only in palatal mesenchyme, showed no abnormality, suggesting that failed palatal elevation in Wnt1-Cre; Fam20b^f/f mice was secondary to micrognathia. In addition, the reduced GAG chains promoted the apoptosis of palatal cells, primarily resulting in reduced cell density and decreased palatal volume. The suppressed BMP signaling and reduced mineralization indicated an impaired osteogenesis of palatine, which could be rescued partially by constitutively active Bmpr1a. Together, our study highlighted the key role of GAG chains in palate morphogenesis.

Endocan Knockdown Down-Regulates the Expression of Angiogenesis-Associated Genes in Il-1ß Activated Chondrocytes

Endocan is a small soluble proteoglycan (PG) known to be involved in inflammation and angiogenesis. Increased endocan expression was found in the synovia of arthritic patients and chondrocytes stimulated with IL-1ß. Considering these findings, we aimed to investigate the effects of endocan knockdown on the modulation of pro-angiogenic molecules expression in a model of IL-1ß-induced inflammation in human articular chondrocytes. Endocan, VEGF-A, MMP-9, MMP-13, and VEGFR-2 expression was measured in both normal and endocan knockdown chondrocytes stimulated with IL-1ß. VEGFR-2 and NF-kB activation were also measured. Results have shown that endocan, VEGF-A, VEGFR-2, MMP-9, and MMP-13 were significantly up-regulated during IL-1ß-induced inflammation; interestingly, the expression of such pro-angiogenic molecules and NF-kB activation were significantly reduced by endocan knockdown. These data support the hypothesis that endocan released by activated chondrocytes may be involved in the mechanisms that stimulate cell migration and invasion, as well as angiogenesis, in the pannus of arthritic joints.

Contribution of intramuscular connective tissue and its structural components on meat tenderness-revisited: a review

The tenderness of meat influences consumers' perceptions of its quality. Meat tenderness is a key quality characteristic that influences consumer satisfaction, repeat purchases, and willingness to pay higher prices for meat. Muscle fibers, connective tissues, and adipocytes are the main structural components of meat that contribute to its tenderness and texture. In the present review, we have focused on the role of connective tissue and its components in meat tenderness, specifically perimysial intramuscular connective tissue (IMCT) and its concept as an immutable "background toughness." The collagen contribution to cooked meat toughness can be altered by animal diet, compensatory growth, slaughter age, aging, and cooking. As well, progressive thickening of the perimysium leads to a progressive increase in shear force values in beef, pork, chicken, and this may occur prior to adipocyte formation as cattle finish in feedlots. Conversely, adipocyte accumulation in the perimysium can decrease cooked meat shear force, suggesting that the contribution of IMCT to meat toughness is complex and driven by both collagen structure and content. This review provides a theoretical foundation of information to modify IMCT components to improve meat tenderness.

Methadone alters transcriptional programs associated with synapse formation in human cortical organoids

Opioid use disorder (OUD) among pregnant women has become an epidemic in the United States. Pharmacological interventions for maternal OUD most commonly involve methadone, a synthetic opioid analgesic that attenuates withdrawal symptoms and behaviors linked with drug addiction. However, evidence of methadone's ability to readily accumulate in neural tissue, and cause long-term neurocognitive sequelae, has led to concerns regarding its effect on prenatal brain development. We utilized human cortical organoid (hCO) technology to probe how this drug impacts the earliest mechanisms of cortico-genesis. Bulk mRNA sequencing of 2-month-old hCOs chronically treated with a clinically relevant dose of 1 μM methadone for 50 days revealed a robust transcriptional response to methadone associated with functional components of the synapse, the underlying extracellular matrix (ECM), and cilia. Co-expression network and predictive protein-protein interaction analyses demonstrated that these changes occurred in concert, centered around a regulatory axis of growth factors, developmental signaling pathways, and matricellular proteins (MCPs). TGFβ1 was identified as an upstream regulator of this network and appeared as part of a highly interconnected cluster of MCPs, of which thrombospondin 1 (TSP1) was most prominently downregulated and exhibited dose-dependent reductions in protein levels. These results demonstrate that methadone exposure during early cortical development alters transcriptional programs associated with synaptogenesis, and that these changes arise by functionally modulating extra-synaptic molecular mechanisms in the ECM and cilia. Our findings provide novel insight into the molecular underpinnings of methadone's putative effect on cognitive and behavioral development and a basis for improving interventions for maternal opioid addiction.

Dark pigmentation and related low FMOD expression increase IL-3 and facilitate plasmacytoid dendritic cell maturation

According to epidemiological research, skin autoimmune diseases are more prevalent among black Americans. We postulated that pigment-producing melanocytes may contribute to local immune regulation in the microenvironment. We examined murine epidermal melanocytes in vitro to determine the role of pigment production in immune responses mediated by dendritic cell (DC) activation. Our study revealed that darkly pigmented melanocytes produce more IL-3 and the pro-inflammatory cytokines, IL-6 and TNF-α, and consequently induce plasmacytoid DC (pDC) maturation. Additionally, we demonstrate that low pigment-associated fibromodulin (FMOD) interferes with cytokine secretion and subsequent pDC maturation.

Adenomyosis: single-cell transcriptomic analysis reveals a paracrine mesenchymal-epithelial interaction involving the WNT/SFRP pathway

OBJECTIVE

To assess the cellular and molecular landscape of adenomyosis.

DESIGN

Single-cell analysis of genome-wide messenger RNA (mRNA) expression (single-cell RNA sequencing) of matched tissues of endometrium, adenomyosis, and myometrium using relatively large numbers of viable cells.

SETTING

Not applicable.

PATIENT(S)

Patients (n = 3, age range 40-44 years) undergoing hysterectomy for diffuse adenomyosis.

MAIN OUTCOME MEASURE(S)

Definition of the molecular landscape of matched adenomyotic, endometrial and myometrial tissues from the same uterus using single-cell RNA sequencing and comparison of distinct cell types in these tissues to identify disease-specific cell populations, abnormal gene expression and pathway activation, and mesenchymal-epithelial interactions.

RESULT(S)

The largest cell population in the endometrium was composed of closely clustered fibroblast groups, which comprise 36% of all cells and seem to originate from pericyte progenitors differentiating to estrogen/progesterone receptor-expressing endometrial stromal- cells. In contrast, the entire fibroblast population in adenomyosis comprised a larger (50%) portion of all cells and was not linked to any pericyte progenitors. Adenomyotic fibroblasts eventually differentiate into extracellular matrix protein-expressing fibroblasts and smooth muscle cells. Hierarchical clustering of mRNA expression revealed a unique adenomyotic fibroblast population that clustered transcriptomically with endometrial fibroblasts, suggestive of an endometrial stromal cell population serving as progenitors of adenomyosis. Four other adenomyotic fibroblast clusters with disease-specific transcriptomes were distinct from those of endometrial or myometrial fibroblasts. The mRNA levels of the natural WNT inhibitors, named, secreted frizzled-related proteins 1, 2, and 4, were higher in these 4 adenomyotic fibroblast clusters than in endometrial fibroblast clusters. Moreover, we found that multiple WNTs, which originate from fibroblasts and target ciliated and unciliated epithelial cells and endothelial cells, constitute a critical paracrine signaling network in adenomyotic tissue. Compared with endometrial tissue, unciliated and ciliated epithelial cells in adenomyosis comprised a significantly smaller portion of this tissue and exhibited molecular evidence of progesterone resistance and diminished regulation of estrogen signaling.

CONCLUSION(S)

We found a high degree of heterogeneity in fibroblast-like cells in the adenomyotic uterus. The WNT signaling involving differential expression of secreted frizzled-related proteins, which act as decoy receptors for WNTs, in adenomyotic fibroblasts may have a key role in the pathophysiology of this disease.

Targeting Chondroitin Sulphate Synthase 1 (Chsy1) Promotes Axon Growth Following Neurorrhaphy by Suppressing Versican Accumulation

Versican is a chondroitin sulfate proteoglycan (CSPG), which deposits in perineurium as a physical barrier and prevents the growth of axons out of the fascial boundary. Several studies have indicated that the chondroitin sulfate (CS) chains on versican have several possible functions beyond the physical barrier, including the ability to stabilize versican core protein in the extracellular matrix. As chondroitin sulfate synthase 1 (Chsy1) is a crucial enzyme for CS elongation, we hypothesized that in vivo knockdown of Chsy1 at peripheral nerve lesion site may decrease CS and versican accumulation, and result in accelerating neurite regeneration. In the present study, end-to-side neurorrhaphy (ESN) in Wistar rats was used as an in vivo model of peripheral nerve injury to evaluate nerve regeneration after surgical intervention. The distribution and expression of versican and Chsy1 in regenerating axons after ESN was studied using confocal microscopy and western blotting. Chsy1 was silenced at the nerve lesion (surgical) site using in vivo siRNA transfection. The results indicated that Chsy1 was successfully silenced in nerve tissue, and its downregulation was associated with functional recovery of compound muscle action potential. Silencing of Chsy1 also decreased the accumulation of versican core protein, suggesting that transient treating of Chsy1-siRNA may be an alternative and an effective strategy to promote injured peripheral nerve regeneration.

Inter- and intratumoral proteomics and glycosaminoglycan characterization of ALK rearranged lung adenocarcinoma tissues: a pilot study

Lung cancer is one of the most common types of cancer with limited therapeutic options, therefore a detailed understanding of the underlying molecular changes is of utmost importance. In this pilot study, we investigated the proteomic and glycosaminoglycan (GAG) profile of ALK rearranged lung tumor tissue regions based on the morphological classification, mucin and stromal content. Principal component analysis and hierarchical clustering revealed that both the proteomic and GAG-omic profiles are highly dependent on mucin content and to a lesser extent on morphology. We found that differentially expressed proteins between morphologically different tumor types are primarily involved in the regulation of protein synthesis, whereas those between adjacent normal and different tumor regions take part in several other biological processes (e.g. extracellular matrix organization, oxidation-reduction processes, protein folding) as well. The total amount and the sulfation profile of heparan sulfate and chondroitin sulfate showed small differences based on morphology and larger differences based on mucin content of the tumor, while an increase was observed in both the total amount and the average rate of sulfation in tumors compared to adjacent normal regions.

A review of the regulatory mechanisms of extracellular vesicles-mediated intercellular communication

Extracellular vesicles (EVs) are small, membrane-bound structures that are released from cells into the surrounding environment. These structures can be categorized as exosomes, microvesicles, or apoptotic vesicles, and they play an essential role in intercellular communication. These vesicles are attracting significant clinical interest as they offer the potential for drug delivery, disease diagnosis, and therapeutic intervention. To fully understand the regulation of intercellular communication through EVs, it is essential to investigate the underlying mechanisms. This review aims to provide a summary of the current knowledge on the intercellular communications involved in EV targeting, binding, and uptake, as well as the factors that influence these interactions. These factors include the properties of the EVs, the cellular environment, and the recipient cell. As the field of EV-related intercellular communication continues to expand and techniques improve, we can expect to uncover more information about this complex area, despite the current limitations in our knowledge.

Compositional Analysis of Glycosaminoglycans in Different Lung Cancer Types-A Pilot Study

Lung cancer is one of the most commonly diagnosed cancer types. Studying the molecular changes that occur in lung cancer is important to understand tumor formation and identify new therapeutic targets and early markers of the disease to decrease mortality. Glycosaminoglycan chains play important roles in various signaling events in the tumor microenvironment. Therefore, we have determined the quantity and sulfation characteristics of chondroitin sulfate and heparan sulfate in formalin-fixed paraffin-embedded human lung tissue samples belonging to different lung cancer types as well as tumor adjacent normal areas. Glycosaminoglycan disaccharide analysis was performed using HPLC-MS following on-surface lyase digestion. Significant changes were identified predominantly in the case of chondroitin sulfate; for example, the total amount was higher in tumor tissue compared to the adjacent normal tissue. We also observed differences in the degree of sulfation and relative proportions of individual chondroitin sulfate disaccharides between lung cancer types and adjacent normal tissue. Furthermore, the differences in the 6-O-/4-O-sulfation ratio of chondroitin sulfate were different between the lung cancer types. Our pilot study revealed that further investigation of the role of chondroitin sulfate chains and enzymes involved in their biosynthesis is an important aspect of lung cancer research.

Radiotherapy-induced tumor physical microenvironment remodeling to overcome immunotherapy resistance

The clinical benefits of immunotherapy are proven in many cancers, but a significant number of patients do not respond well to immunotherapy. The tumor physical microenvironment (TpME) has recently been shown to affect the growth, metastasis and treatment of solid tumors. The tumor microenvironment (TME) has unique physical hallmarks: 1) unique tissue microarchitecture, 2) increased stiffness, 3) elevated solid stress, and 4) elevated interstitial fluid pressure (IFP), which contribute to tumor progression and immunotherapy resistance in a variety of ways. Radiotherapy, a traditional and powerful treatment, can remodel the matrix and blood flow associated with the tumor to improve the response rate of immune checkpoint inhibitors (ICIs) to a certain extent. Herein, we first review the recent research advances on the physical properties of the TME and then explain how TpME is involved in immunotherapy resistance. Finally, we discuss how radiotherapy can remodel TpME to overcome immunotherapy resistance.

Aberrant protein glycosylation: Implications on diagnosis and Immunotherapy

Glycosylation-mediated post-translational modification is critical for regulating many fundamental processes like cell division, differentiation, immune response, and cell-to-cell interaction. Alterations in the N-linked or O-linked glycosylation pattern of regulatory proteins like transcription factors or cellular receptors lead to many diseases, including cancer. These alterations give rise to micro- and macro-heterogeneity in tumor cells. Here, we review the role of O- and N-linked glycosylation and its regulatory function in autoimmunity and aberrant glycosylation in cancer. The change in cellular glycome could result from a change in the expression of glycosidases or glycosyltransferases like N-acetyl-glucosaminyl transferase V, FUT8, ST6Gal-I, DPAGT1, etc., impact the glycosylation of target proteins leading to transformation. Moreover, the mutations in glycogenes affect glycosylation patterns on immune cells leading to other related manifestations like pro- or anti-inflammatory effects. In recent years, understanding the glycome to cancer indicates that it can be utilized for both diagnosis/prognosis as well as immunotherapy. Studies involving mass spectrometry of proteome, site- and structure-specific glycoproteomics, or transcriptomics/genomics of patient samples and cancer models revealed the importance of glycosylation homeostasis in cancer biology. The development of emerging technologies, such as the lectin microarray, has facilitated research on the structure and function of glycans and glycosylation. Newly developed devices allow for high-throughput, high-speed, and precise research on aberrant glycosylation. This paper also discusses emerging technologies and clinical applications of glycosylation.

Identification of hub genes and pathways in lung metastatic colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most prevalent types of malignant tumours. Metastasis is the leading cause of cancer-related mortality, with lung metastases accounting for 32.9% of all metastatic CRCs. However, since the biological mechanism of lung metastatic CRC is poorly understood, limited therapeutic targets are available. In the present study, we aimed to identify the key genes and molecular processes involved in CRC lung metastasis.

METHODS

The differentially expressed genes (DEGs) between primary and lung metastatic CRC patients were obtained from the Gene Expression Omnibus (GEO) database via the GEO2R tool. The enriched biological processes and pathways modulated by the DEGs were determined with Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome Gene Sets analyses. The search tool Retrieval of Interacting Genes (STRING) and Cytoscape were used to construct a protein-protein interaction (PPI) network among DEGs.

RESULTS

The DEGs were enriched in surfactant metabolism, cell-cell communication and chemokine signaling pathways. The defined hub genes were included CLU, SFTPD, CCL18, SPP1, APOE, BGN and MMP3. Among them, CLU, SFTPD and CCL18 might be associated with the specific lung tropism metastasis in CRC. In addition, the expression and prognostic values of the hub genes in CRC patients were verified in database of The Cancer Genome Atlas (TCGA) and GEO. Moreover, the protein levels of the hub genes were detected in primary and lung metastatic CRC cells, serum or tissues. Furthermore, SFTPD was confirmed to facilitate cellular proliferation and lung metastasis in CRC.

CONCLUSION

This bioinformatics study may provide a better understanding of the candidate therapeutic targets and molecular mechanisms for CRC lung metastasis.

The Extracellular Matrix: Its Composition, Function, Remodeling, and Role in Tumorigenesis

The extracellular matrix (ECM) is a ubiquitous member of the body and is key to the maintenance of tissue and organ integrity. Initially thought to be a bystander in many cellular processes, the extracellular matrix has been shown to have diverse components that regulate and activate many cellular processes and ultimately influence cell phenotype. Importantly, the ECM's composition, architecture, and stiffness/elasticity influence cellular phenotypes. Under normal conditions and during development, the synthesized ECM constantly undergoes degradation and remodeling processes via the action of matrix proteases that maintain tissue homeostasis. In many pathological conditions including fibrosis and cancer, ECM synthesis, remodeling, and degradation is dysregulated, causing its integrity to be altered. Both physical and chemical cues from the ECM are sensed via receptors including integrins and play key roles in driving cellular proliferation and differentiation and in the progression of various diseases such as cancers. Advances in 'omics' technologies have seen an increase in studies focusing on bidirectional cell-matrix interactions, and here, we highlight the emerging knowledge on the role played by the ECM during normal development and in pathological conditions. This review summarizes current ECM-targeted therapies that can modify ECM tumors to overcome drug resistance and better cancer treatment.

Genome-wide identification of potential odontogenic genes involved in the dental epithelium-mesenchymal interaction during early odontogenesis

BACKGROUND

Epithelium-mesenchymal interactions are involved in odontogenic processes. Previous studies have focused on the intracellular signalling regulatory network in tooth development, but the functions of extracellular regulatory molecules have remained unclear. This study aims to explore the gene profile of extracellular proteoglycans and their glycosaminoglycan chains potentially involved in dental epithelium-mesenchymal interactions using high-throughput sequencing to provide new understanding of early odontogenesis.

RESULTS

Whole transcriptome profiles of the mouse dental epithelium and mesenchyme were investigated by RNA sequencing (RNA-seq). A total of 1,281 and 1,582 differentially expressed genes were identified between the dental epithelium and mesenchyme at E11.5 and E13.5, respectively. Enrichment analysis showed that extracellular regions and ECM-receptor interactions were significantly enriched at both E11.5 and E13.5. Polymerase chain reaction analysis confirmed that the extracellular proteoglycan family exhibited distinct changes during epithelium-mesenchymal interactions. Most proteoglycans showed higher transcript levels in the dental mesenchyme, whereas only a few were upregulated in the epithelium at both stages. In addition, 9 proteoglycans showed dynamic expression changes between these two tissue compartments. Gpc4, Sdc2, Spock2, Dcn and Lum were expressed at higher levels in the dental epithelium at E11.5, whereas their expression was significantly higher in the dental mesenchyme at E13.5, which coincides with the odontogenic potential shift. Moreover, the glycosaminoglycan biosynthetic enzymes Ext1, Hs3st1/5, Hs6st2/3, Ndst3 and Sulf1 also exhibited early upregulation in the epithelium but showed markedly higher expression in the mesenchyme after the odontogenic potential shift.

CONCLUSION

This study reveals the dynamic expression profile of extracellular proteoglycans and their biosynthetic enzymes during the dental epithelium-mesenchymal interaction. This study offers new insight into the roles of extracellular proteoglycans and their distinct sulfation underlying early odontogenesis.

A 3D Tumor-Mimicking In Vitro Drug Release Model of Locoregional Chemoembolization Using Deep Learning-Based Quantitative Analyses

Primary liver cancer, with the predominant form as hepatocellular carcinoma (HCC), remains a worldwide health problem due to its aggressive and lethal nature. Transarterial chemoembolization, the first-line treatment option of unresectable HCC that employs drug-loaded embolic agents to occlude tumor-feeding arteries and concomitantly delivers chemotherapeutic drugs into the tumor, is still under fierce debate in terms of the treatment parameters. The models that can produce in-depth knowledge of the overall intratumoral drug release behavior are lacking. This study engineers a 3D tumor-mimicking drug release model, which successfully overcomes the substantial limitations of conventional in vitro models through utilizing decellularized liver organ as a drug-testing platform that uniquely incorporates three key features, i.e., complex vasculature systems, drug-diffusible electronegative extracellular matrix, and controlled drug depletion. This drug release model combining with deep learning-based computational analyses for the first time permits quantitative evaluation of all important parameters associated with locoregional drug release, including endovascular embolization distribution, intravascular drug retention, and extravascular drug diffusion, and establishes long-term in vitro-in vivo correlations with in-human results up to 80 d. This model offers a versatile platform incorporating both tumor-specific drug diffusion and elimination settings for quantitative evaluation of spatiotemporal drug release kinetics within solid tumors.

Conditional expression of endorepellin in the tumor vasculature attenuates breast cancer growth, angiogenesis and hyaluronan deposition

The tumor stroma of most solid malignancies is characterized by a pathological accumulation of pro-angiogenic and pro-tumorigenic hyaluronan driving tumorigenesis and metastatic potential. Of all three hyaluronan synthase isoforms, HAS2 is the primary enzyme that promotes the build-up of tumorigenic HA in breast cancer. Previously, we discovered that endorepellin, the angiostatic C-terminal fragment of perlecan, evokes a catabolic mechanism targeting endothelial HAS2 and hyaluronan via autophagic induction. To explore the translational implications of endorepellin in breast cancer, we created a double transgenic, inducible Tie2CreERT2;endorepellin(ER)Ki mouse line that expresses recombinant endorepellin specifically from the endothelium. We investigated the therapeutic effects of recombinant endorepellin overexpression in an orthotopic, syngeneic breast cancer allograft mouse model. First, adenoviral delivery of Cre evoking intratumor expression of endorepellin in ERKi mice suppressed breast cancer growth, peritumor hyaluronan and angiogenesis. Moreover, tamoxifen-induced expression of recombinant endorepellin specifically from the endothelium in Tie2CreERT2;ERKi mice markedly suppressed breast cancer allograft growth, hyaluronan deposition in the tumor proper and perivascular tissues, and tumor angiogenesis. These results provide insight into the tumor suppressing activity of endorepellin at the molecular level and implicate endorepellin as a promising cancer protein therapy that targets hyaluronan in the tumor microenvironment.

HBx downregulated decorin and decorin-derived peptides inhibit the proliferation and tumorigenicity of hepatocellular carcinoma cells

Hepatitis B virus (HBV) is one of the important risk factors in inducing the occurrence and development of liver cancer, while the mechanism has not been fully clarified. In this study, we found decorin (DCN) was significantly reduced in HBV transgenic cell line HepG2-4D14 compared to HepG2. The data from hepatocellular carcinoma (HCC) patients indicated that the level of DCN mRNA was significantly lower in tumor tissues than healthy control and positively correlated with the survival of HCC patients. We revealed that HBV HBx can inhibit the transcription of DCN by blocking p53 activity. Functional analysis demonstrated that overexpression of DCN substantially inhibits the proliferation of HCC cells, while knockdown of DCN enhances the proliferation of HCC cells. It is known that DCN could competitively bind to c-Met to inhibit HGF/c-Met signaling pathway to inhibit the development of HCC. Therefore, we screened the novel antitumor peptides derived from DCN based on the sequence of DCN and the complex structure of HGF/c-Met with virtual screening and identified a set of DCN-derived peptides (DCN-Ps) which may competitively bind to c-Met. We found that 5 of peptides can reduce the proliferation and migration of HepG2 cells significantly. Among them, DCN-P#3 can inhibit the growth of HCC cells both in vitro and in vivo. In conclusion, we discovered that HBV HBx downregulates the expression of DCN, which in turn promotes the proliferation of hepatocytes and the development of HCC. We identified DCN-derived antitumor peptides which provides the candidates for developing novel drugs against HCC.

The Matrix Reloaded-The Role of the Extracellular Matrix in Cancer

As the core component of all organs, the extracellular matrix (ECM) is an interlocking macromolecular meshwork of proteins, glycoproteins, and proteoglycans that provides mechanical support to cells and tissues. In cancer, the ECM can be remodelled in response to environmental cues, and it controls a plethora of cellular functions, including metabolism, cell polarity, migration, and proliferation, to sustain and support oncogenesis. The biophysical and biochemical properties of the ECM, such as its structural arrangement and being a reservoir for bioactive molecules, control several intra- and intercellular signalling pathways and induce cytoskeletal changes that alter cell shapes, behaviour, and viability. Desmoplasia is a major component of solid tumours. The abnormal deposition and composition of the tumour matrix lead to biochemical and biomechanical alterations that determine disease development and resistance to treatment. This review summarises the complex roles of ECM in cancer and highlights the possible therapeutic targets and how to potentially remodel the dysregulated ECM in the future. Furthering our understanding of the ECM in cancer is important as the modification of the ECM will probably become an important tool in the characterisation of individual tumours and personalised treatment options.

SPOCK1 Overexpression Suggests Poor Prognosis of Ovarian Cancer

Purpose: Sparc/osteonectin, cwcv, and kazal-like domains proteoglycan 1 (SPOCK1) has been found in a variety of malignant tumors and is associated with a poor prognosis. We aimed to explore the role of SPOCK1 in ovarian cancer. Methods: Ovarian cancer cell lines SKOV3 and SW626 were transfected with SPOCK1 overexpressing or empty vector using electroporation. Cells were studied by immunostaining and an automated Western blotting system. BrdU uptake and wound healing assays assessed cell proliferation and migration. SPOCK1 expression in human ovarian cancer tissues and in blood samples were studied by immunostaining and ELISA. Survival of patients with tumors exhibiting low and high SPOCK1 expression was analyzed using online tools. Results: Both transfected cell lines synthesized different SPOCK1 variants; SKOV3 cells also secreted the proteoglycan. SPOCK1 overexpression stimulated DNA synthesis and cell migration involving p21CIP1. Ovarian cancer patients had increased SPOCK1 serum levels compared to healthy controls. Tumor cells of tissues also displayed abundant SPOCK1. Moreover, SPOCK1 levels were higher in untreated ovarian cancer serum and tissue samples and lower in recipients of chemotherapy. According to in silico analyses, high SPOCK1 expression was correlated with shorter survival. Conclusion: Our findings suggest SPOCK1 may be a viable anti-tumor therapeutic target and could be used for monitoring ovarian cancer.

Mesenchyme-derived vertebrate lonesome kinase controls lung organogenesis by altering the matrisome

Vertebrate lonesome kinase (VLK) is the only known secreted tyrosine kinase and responsible for the phosphorylation of a broad range of secretory pathway-resident and extracellular matrix proteins. However, its cell-type specific functions in vivo are still largely unknown. Therefore, we generated mice lacking the VLK gene (protein kinase domain containing, cytoplasmic (Pkdcc)) in mesenchymal cells. Most of the homozygous mice died shortly after birth, most likely as a consequence of their lung abnormalities and consequent respiratory failure. E18.5 embryonic lungs showed a reduction of alveolar type II cells, smaller bronchi, and an increased lung tissue density. Global mass spectrometry-based quantitative proteomics identified 97 proteins with significantly and at least 1.5-fold differential abundance between genotypes. Twenty-five of these had been assigned to the extracellular region and 15 to the mouse matrisome. Specifically, fibromodulin and matrilin-4, which are involved in extracellular matrix organization, were significantly more abundant in lungs from Pkdcc knockout embryos. These results support a role for mesenchyme-derived VLK in lung development through regulation of matrix dynamics and the resulting modulation of alveolar epithelial cell differentiation.

Mucopolysaccharidoses Differential Diagnosis by Mass Spectrometry-Based Analysis of Urine Free Glycosaminoglycans—A Diagnostic Prediction Model

Impaired glycosaminoglycans (GAGs) catabolism may lead to a cluster of rare metabolic and genetic disorders called mucopolysaccharidoses (MPSs). Each subtype is caused by the deficiency of one of the lysosomal hydrolases normally degrading GAGs. Affected tissues accumulate undegraded GAGs in cell lysosomes and in the extracellular matrix, thus leading to the MPS complex clinical phenotype. Although each MPS may present with recognizable signs and symptoms, these may often overlap between subtypes, rendering the diagnosis difficult and delayed. Here, we performed an exploratory analysis to develop a model that predicts MPS subtypes based on UHPLC-MS/MS measurement of a urine free GAG profile (or GAGome). We analyzed the GAGome of 78 subjects (38 MPS, 37 healthy and 3 with other MPS symptom-overlapping disorders) using a standardized kit in a central-blinded laboratory. We observed several MPS subtype-specific GAGome changes. We developed a multivariable penalized Lasso logistic regression model that attained 91.2% balanced accuracy to distinguish MPS type II vs. III vs. any other subtype vs. not MPS, with sensitivity and specificity ranging from 73.3% to 91.7% and from 98.4% to 100%, depending on the predicted subtype. In conclusion, the urine GAGome was revealed to be useful in accurately discriminating the different MPS subtypes with a single UHPLC-MS/MS run and could serve as a reliable diagnostic test for a more rapid MPS biochemical diagnosis.

Tissue-specific expression of carbohydrate sulfotransferases drives keratan sulfate biosynthesis in the notochord and otic vesicles of Xenopus embryos

Keratan sulfate (KS) is a glycosaminoglycan that is enriched in vertebrate cornea, cartilage, and brain. During embryonic development, highly sulfated KS (HSKS) is first detected in the developing notochord and then in otic vesicles; therefore, HSKS has been used as a molecular marker of the notochord. However, its biosynthetic pathways and functional roles in organogenesis are little known. Here, I surveyed developmental expression patterns of genes related to HSKS biosynthesis in Xenopus embryos. Of these genes, the KS chain-synthesizing glycosyltransferase genes, beta-1,3-N-acetylglucosaminyltransferase (b3gnt7) and beta-1,4-galactosyltransferase (b4galt4), are strongly expressed in the notochord and otic vesicles, but also in other tissues. In addition, their notochord expression is gradually restricted to the posterior end at the tailbud stage. In contrast, carbohydrate sulfotransferase (Chst) genes, chst2, chst3, and chst5.1, are expressed in both notochord and otic vesicles, whereas chst1, chst4/5-like, and chst7 are confined to otic vesicles. Because the substrate for Chst1 and Chst3 is galactose, while that for others is N-acetylglucosamine, combinatorial, tissue-specific expression patterns of Chst genes should be responsible for tissue-specific HSKS enrichment in embryos. As expected, loss of function of chst1 led to loss of HSKS in otic vesicles and reduction of their size. Loss of chst3 and chst5.1 resulted in HSKS loss in the notochord. These results reveal that Chst genes are critical for HSKS biosynthesis during organogenesis. Being hygroscopic, HSKS forms “water bags” in embryos to physically maintain organ structures. In terms of evolution, in ascidian embryos, b4galt and chst-like genes are also expressed in the notochord and regulate notochord morphogenesis. Furthermore, I found that a chst-like gene is also strongly expressed in the notochord of amphioxus embryos. These conserved expression patterns of Chst genes in the notochord of chordate embryos suggest that Chst is an ancestral component of the chordate notochord.

Removal of GAGs Regulates Mechanical Properties, Collagen Fiber Formation, and Alignment in Tissue Engineered Meniscus

The complex fibrillar architecture of native meniscus is essential for proper function and difficult to recapitulate in vitro. In the native meniscus, proteoglycan content is low during the development of collagen fibers and progressively increases with aging. In vitro, fibrochondrocytes produce glycosaminoglycans (GAGs) early in culture, in contrast to native tissue, where they are deposited after collagen fibers have formed. This difference in the timing of GAG production hinders the formation of a mature fiber network in such in vitro models. In this study, we removed GAGs from collagen gel-based tissue engineered constructs using chondroitinase ABC (cABC) and evaluated the effect on the formation and alignment of collagen fibers and the subsequent effect on tensile and compressive mechanical properties. Removal of GAGs during maturation of in vitro constructs improved collagen fiber alignment in tissue engineered meniscus constructs. Additionally, removal of GAGs during maturation improved fiber alignment without compromising compressive strength, and this removal improved not only fiber alignment and formation but also tensile properties. The increased fiber organization in cABC-treated groups also appeared to influence the size, shape, and location of defects in these constructs, suggesting that treatment may prevent the propagation of large defects under loading. This data gives another method of modulating the ECM for improved collagen fiber formation and mechanical properties in tissue engineered constructs.

10 years of extracellular matrix proteomics: Accomplishments, challenges, and future perspectives

The extracellular matrix (ECM) is a complex assembly of hundreds of proteins forming the architectural scaffold of multicellular organisms. In addition to its structural role, the ECM conveys signals orchestrating cellular phenotypes. Alterations of ECM composition, abundance, structure, or mechanics, have been linked to diseases and disorders affecting all physiological systems, including fibrosis and cancer. Deciphering the protein composition of the ECM and how it changes in pathophysiological contexts is thus the first step toward understanding the roles of the ECM in health and disease and toward the development of therapeutic strategies to correct disease-causing ECM alterations. Potentially, the ECM also represents a vast, yet untapped reservoir of disease biomarkers. ECM proteins are characterized by unique biochemical properties that have hindered their study: they are large, heavily and uniquely post-translationally modified, and highly insoluble. Overcoming these challenges, we and others have devised mass-spectrometry-based proteomic approaches to define the ECM composition, or "matrisome", of tissues. This review provides a historical overview of ECM proteomics research and presents the latest advances that now allow the profiling of the ECM of healthy and diseased tissues. The second part highlights recent examples illustrating how ECM proteomics has emerged as a powerful discovery pipeline to identify prognostic cancer biomarkers. The third part discusses remaining challenges limiting our ability to translate findings to clinical application and proposes approaches to overcome them. Last, the review introduces readers to resources available to facilitate the interpretation of ECM proteomics datasets. The ECM was once thought to be impenetrable. MS-based proteomics has proven to be a powerful tool to decode the ECM. In light of the progress made over the past decade, there are reasons to believe that the in-depth exploration of the matrisome is within reach and that we may soon witness the first translational application of ECM proteomics.

The Interplay of Glycosaminoglycans and Cysteine Cathepsins in Mucopolysaccharidosis

Mucopolysaccharidosis (MPS) consists of a group of inherited lysosomal storage disorders that are caused by a defect of certain enzymes that participate in the metabolism of glycosaminoglycans (GAGs). The abnormal accumulation of GAGs leads to progressive dysfunctions in various tissues and organs during childhood, contributing to premature death. As the current therapies are limited and inefficient, exploring the molecular mechanisms of the pathology is thus required to address the unmet needs of MPS patients to improve their quality of life. Lysosomal cysteine cathepsins are a family of proteases that play key roles in numerous physiological processes. Dysregulation of cysteine cathepsins expression and activity can be frequently observed in many human diseases, including MPS. This review summarizes the basic knowledge on MPS disorders and their current management and focuses on GAGs and cysteine cathepsins expression in MPS, as well their interplay, which may lead to the development of MPS-associated disorders.

Glycomics by ion mobility tandem mass spectrometry of chondroitin sulfate disaccharide domain in biglycan

Biglycan (BGN), a small leucine-rich repeat proteoglycan, is involved in a variety of pathological processes including malignant transformation, for which the upregulation of BGN was found related to cancer cell invasiveness. Because the functions of BGN are mediated by its chondroitin/dermatan sulfate (CS/DS) chains through the sulfates, the determination of CS/DS structure and sulfation pattern is of major importance. In this study, we have implemented an advanced glycomics method based on ion mobility separation (IMS) mass spectrometry (MS) and tandem MS (MS/MS) to characterize the CS disaccharide domains in BGN. The high separation efficiency and sensitivity of this technique allowed the discrimination of five distinct CS disaccharide motifs, of which four irregulated in their sulfation pattern. For the first time, trisulfated unsaturated and bisulfated saturated disaccharides were found in BGN, the latter species documenting the non-reducing end of the chains. The structural investigation by IMS MS/MS disclosed that in one or both of the CS/DS chains, the non-reducing end is 3-O-sulfated GlcA in a rather rare bisulfated motif having the structure 3-O-sulfated GlcA-4-O-sulfated GalNAc. Considering the role played by BGN in cancer cell spreading, the influence on this process of the newly identified sequences will be investigated in the future.

Probing the effects of matrix-derived microcarrier composition on human adipose-derived stromal cells cultured dynamically within spinner flask bioreactors

Recognizing the cell-instructive capacity of the extracellular matrix (ECM), this study investigated the effects of expanding human adipose-derived stromal cells (hASCs) on ECM-derived microcarriers fabricated from decellularized adipose tissue (DAT) or decellularized cartilage tissue (DCT) within spinner flask bioreactors. Protocols were established for decellularizing porcine auricular cartilage and electrospraying methods were used to generate microcarriers comprised exclusively of DAT or DCT, which were compositionally distinct, but had matching Young's moduli. Both microcarrier types supported hASC attachment and growth over 14 days within a low-shear spinner culture system, with a significantly higher cell density observed on the DCT microcarriers at 7 and 14 days. Irrespective of the ECM source, dynamic culture on the microcarriers altered the expression of genes and proteins associated with cell adhesion and ECM remodeling. Label-free mass spectrometry analysis showed upregulation of proteins associated with cartilage development and ECM in the hASCs expanded on the DCT microcarriers. Based on Luminex analysis, the hASCs expanded on the DCT microcarriers secreted significantly higher levels of IL-8 and PDGFAA, supporting that the ECM source can modulate hASC paracrine factor secretion. Finally, the hASCs expanded on the microcarriers were extracted for analysis of adipogenic and chondrogenic differentiation relative to baseline controls. The microcarrier-cultured hASCs showed enhanced intracellular lipid accumulation at 7 days post-induction of adipogenic differentiation. In the chondrogenic studies, a low level of differentiation was observed in all groups. Future studies are warranted using alternative cell sources with greater chondrogenic potential to further assess the chondro-inductive properties of the DCT microcarriers.

Age-dependent mechanical properties of tail tendons in wild-type and mimecan gene-knockout mice - A preliminary study

Mimecan, or osteoglycin, belongs to the family of small leucine-rich proteoglycans. In connective tissues mimecan is implicated in the development and maintenance of normal collagen fibrillar organization. Since collagen fibrils are responsible for tissue reinforcement, the absence of mimecan could lead to abnormal tissue mechanical properties. Here, we carried out a preliminary investigation of possible changes in the mechanical properties of tendons in mice lacking a functional mimecan gene, as a function of age. Tail tendons were dissected from mimecan gene knockout (KO) and wild type (WT) mice at ages 1, 4 and 8 months and mechanical properties evaluated using a microtensile testing equipment. Mimecan gene knockout resulted in changes in tendon elasticity- and fracture-related properties. While tendons of WT mice exhibited enhanced mechanical properties with increasing age, this trend was notably attenuated in mimecan KO tendons, with the exception of fracture strain. When genotype and age were considered as cross factors, the diminution in the mechanical properties of mimecan KO tendons was significant for yield strength, modulus and fracture strength. This effect appeared to affect the mice at 4 month old. These preliminary results suggest that mimecan may have a role in regulating age-dependent mechanical function in mouse tail tendon.

Pulmonary Vascular Remodeling in Pulmonary Hypertension

Pulmonary vascular remodeling is the critical structural alteration and pathological feature in pulmonary hypertension (PH) and involves changes in the intima, media and adventitia. Pulmonary vascular remodeling consists of the proliferation and phenotypic transformation of pulmonary artery endothelial cells (PAECs) and pulmonary artery smooth muscle cells (PASMCs) of the middle membranous pulmonary artery, as well as complex interactions involving external layer pulmonary artery fibroblasts (PAFs) and extracellular matrix (ECM). Inflammatory mechanisms, apoptosis and other factors in the vascular wall are influenced by different mechanisms that likely act in concert to drive disease progression. This article reviews these pathological changes and highlights some pathogenetic mechanisms involved in the remodeling process.

Expression of Basement Membrane Molecules by Wharton Jelly Stem Cells (WJSC) in Full-Term Human Umbilical Cords, Cell Cultures and Microtissues

Wharton's jelly stem cells (WJSC) from the human umbilical cord (UC) are one of the most promising mesenchymal stem cells (MSC) in tissue engineering (TE) and advanced therapies. The cell niche is a key element for both, MSC and fully differentiated tissues, to preserve their unique features. The basement membrane (BM) is an essential structure during embryonic development and in adult tissues. Epithelial BMs are well-known, but similar structures are present in other histological structures, such as in peripheral nerve fibers, myocytes or chondrocytes. Previous studies suggest the expression of some BM molecules within the Wharton's Jelly (WJ) of UC, but the distribution pattern and full expression profile of these molecules have not been yet elucidated. In this sense, the aim of this histological study was to evaluate the expression of main BM molecules within the WJ, cultured WJSC and during WJSC microtissue (WJSC-MT) formation process. Results confirmed the presence of a pericellular matrix composed by the main BM molecules-collagens (IV, VII), HSPG2, agrin, laminin and nidogen-around the WJSC within UC. Additionally, ex vivo studies demonstrated the synthesis of these BM molecules, except agrin, especially during WJSC-MT formation process. The WJSC capability to synthesize main BM molecules could offer new alternatives for the generation of biomimetic-engineered substitutes where these molecules are particularly needed.

The chondro-osseous junction of articular cartilage

In the synovial joints the transition between the soft articular cartilage and the subchondral bone is mediated by a layer of calcified cartilage of structural and mechanical characteristics closer to those of bone. This layer, buried in the depth of articular cartilage, is not directly accessible and is mostly visualized in histological sections of decalcified tissue, where it appears as a darker strip in contact with the subchondral bone. In this study conventional histology and scanning electron microscopy (SEM) with secondary electron imaging (SE) or backscattered electron imaging (BSE) were used to discriminate the calcified and the uncalcified cartilage in high resolution on native, untreated tissue as well as in deproteinated or demineralized tissue. This approach evidenced a high heterogeneity of the calcified layer of articular cartilage. High resolution pictures revealed that the mineralization process originates by progressive accretion and confluence of individual, small mineral clusters, in a very different way from other hard tissues such as bone, dentin and mineralized tendons. Finally, selective removal of the soft matrix by thermal treatment allowed for the first time a face-on, unrestricted 3D view of the mineralization front.

PCV2 Uptake by Porcine Monocytes Is Strain-Dependent and Is Associated with Amino Acid Characteristics on the Capsid Surface

Porcine circovirus type 2 (PCV2) is associated with several economically important diseases that are described as PCV2-associated diseases (PCVADs). PCV2 is replicating in lymphoblasts, and PCV2 particles are taken up by monocytes without effective replication or complete degradation. Glycosaminoglycans (GAGs) have been demonstrated to be important receptors for PCV2 binding and entry in T-lymphocytes and continuous cell lines. The objective of this study was to determine whether differences exist in viral uptake and outcome among six PCV2 strains from different disease outbreaks in primary porcine monocytes: Stoon-1010 (PCV2a; PMWS), 1121 (PCV2a; abortion), 1147 (PCV2b; PDNS), 09V448 (PCV2d-1; PCVAD with high viral load in lymphoid tissues [PCVADhigh]), DE222-13 (PCV2d-2; PCVADhigh), and 19V245 (PCV2d-2; PCVADhigh). The uptake of PCV2 in peripheral blood monocytes was different among the PCV2 strains. A large number of PCV2 particles were found in the monocytes for Stoon-1010, DE222-13, and 19V245, while a low number was found for 1121, 1147, and 09V448. Competition with, and removal of GAGs on the cell surface, demonstrated an important role of chondroitin sulfate (CS) and dermatan sulfate (DS) in PCV2 entry into monocytes. The mapping of positively/negatively charged amino acids exposed on the surface of PCV2 capsids revealed that their number and distribution could have an impact on the binding of the capsids to GAGs, and the internalization into monocytes. Based on the distribution of positively charged amino acids on PCV2 capsids, phosphacan was hypothesized, and further demonstrated, as an effective candidate to mediate virus attachment to, and internalization in, monocytes. IMPORTANCE PCV2 is present on almost every pig farm in the world and is associated with a high number of diseases (PCV2-associated diseases [PCVADs]). It causes severe economic losses. Although vaccination is successfully applied in the field, there are still a lot of unanswered questions on the pathogenesis of PCV2 infections. This article reports on the uptake difference of various PCV2 strains by peripheral blood monocytes, and reveals the mechanism of the strong viral uptake ability of monocytes of Piétrain pigs. We further demonstrated that: (i) GAGs mediate the uptake of PCV2 particles by monocytes, (ii) positively charged three-wings-windmill-like amino acid patterns on the capsid outer surface are activating PCV2 uptake, and (iii) phosphacan is one of the potential candidates for PCV2 internalization. These results provide new insights into the mechanisms involved in PCVAD and contribute to a better understanding of PCV2 evolution. This may lead to the development of resistant pigs.

Screening of Biomarkers in Liver Tissue after Bariatric Surgery Based on WGCNA and SVM-RFE Algorithms

As the most common chronic liver disease around the world, nonalcoholic fatty liver disease (NAFLD) has a close connection with obesity, diabetes, and metabolic syndrome. Bariatric surgery (BS) is considered to be the most effective treatment for NAFLD. However, the regulatory mechanism of hepatic lipid metabolism after BS remains poorly elucidated. By analyzing two transcriptome datasets regarding liver tissues after BS, namely, GSE83452 and GSE106737, we acquired 110 differentially expressed genes (DEGs). By further analysis of DEGs in terms of the weighted gene coexpression network analysis (WGCNA) and support vector machine-recursive feature elimination (SVM-RFE) algorithms, we identified four crucial genes participating in the regulation of hepatic lipid metabolism: SRGN, THEMIS2, SGK1, and FPR3. In addition, the results of gene set enrichment analysis (GSEA) showed that BS can activate immune-related regulatory pathways and change immune cell infiltration levels. Finally, through cellular level studies, we found that the silencing of SRGN affects the expression of SREBP-1, SIRT1, and FAS during adipogenesis in the liver and the formation of lipid droplets in the liver. In summary, the immune system in the liver is activated after BS, and SRGN participates in the regulation of hepatic lipid metabolism.

In Silico Analysis of a Drosophila Parasitoid Venom Peptide Reveals Prevalence of the Cation-Polar-Cation Clip Motif in Knottin Proteins

As generalist parasitoid wasps, Leptopilina heterotoma are highly successful on many species of fruit flies of the genus Drosophila. The parasitoids produce specialized multi-strategy extracellular vesicle (EV)-like structures in their venom. Proteomic analysis identified several immunity-associated proteins, including the knottin peptide, LhKNOT, containing the structurally conserved inhibitor cysteine knot (ICK) fold, which is present in proteins from diverse taxa. Our structural and docking analysis of LhKNOT's 36-residue core knottin fold revealed that in addition to the knottin motif itself, it also possesses a Cation-Polar-Cation (CPC) clip. The CPC clip motif is thought to facilitate antimicrobial activity in heparin-binding proteins. Surprisingly, a majority of ICKs tested also possess the CPC clip motif, including 75 bona fide plant and arthropod knottin proteins that share high sequence and/or structural similarity with LhKNOT. Like LhKNOT and these other 75 knottin proteins, even the Drosophila Drosomycin antifungal peptide, a canonical target gene of the fly's Toll-NF-kappa B immune pathway, contains this CPC clip motif. Together, our results suggest a possible defensive function for the parasitoid LhKNOT. The prevalence of the CPC clip motif, intrinsic to the cysteine knot within the knottin proteins examined here, suggests that the resultant 3D topology is important for their biochemical functions. The CPC clip is likely a highly conserved structural motif found in many diverse proteins with reported heparin binding capacity, including amyloid proteins. Knottins are targets for therapeutic drug development, and insights into their structure-function relationships will advance novel drug design.

HS, an Ancient Molecular Recognition and Information Storage Glycosaminoglycan, Equips HS-Proteoglycans with Diverse Matrix and Cell-Interactive Properties Operative in Tissue Development and Tissue Function in Health and Disease

Heparan sulfate is a ubiquitous, variably sulfated interactive glycosaminoglycan that consists of repeating disaccharides of glucuronic acid and glucosamine that are subject to a number of modifications (acetylation, de-acetylation, epimerization, sulfation). Variable heparan sulfate chain lengths and sequences within the heparan sulfate chains provide structural diversity generating interactive oligosaccharide binding motifs with a diverse range of extracellular ligands and cellular receptors providing instructional cues over cellular behaviour and tissue homeostasis through the regulation of essential physiological processes in development, health, and disease. heparan sulfate and heparan sulfate-PGs are integral components of the specialized glycocalyx surrounding cells. Heparan sulfate is the most heterogeneous glycosaminoglycan, in terms of its sequence and biosynthetic modifications making it a difficult molecule to fully characterize, multiple ligands also make an elucidation of heparan sulfate functional properties complicated. Spatio-temporal presentation of heparan sulfate sulfate groups is an important functional determinant in tissue development and in cellular control of wound healing and extracellular remodelling in pathological tissues. The regulatory properties of heparan sulfate are mediated via interactions with chemokines, chemokine receptors, growth factors and morphogens in cell proliferation, differentiation, development, tissue remodelling, wound healing, immune regulation, inflammation, and tumour development. A greater understanding of these HS interactive processes will improve therapeutic procedures and prognoses. Advances in glycosaminoglycan synthesis and sequencing, computational analytical carbohydrate algorithms and advanced software for the evaluation of molecular docking of heparan sulfate with its molecular partners are now available. These advanced analytic techniques and artificial intelligence offer predictive capability in the elucidation of heparan sulfate conformational effects on heparan sulfate-ligand interactions significantly aiding heparan sulfate therapeutics development.