Decorin attenuates hypertrophic scar fibrosis via TGFß/Smad signalling.

The management of hypertrophic scars (HSs), characterized by excessive collagen production, involves various nonsurgical and surgical interventions. However, the absence of a well-defined molecular mechanism governing hypertrophic scarring has led to less-than-ideal results in clinical antifibrotic treatments. Therefore, our study focused on the role of decorin (DCN) and its regulatory role in the TGF-ß/Smad signalling pathway in the development of HSs. In our research, we observed a decrease in DCN expression within hypertrophic scar tissue and its derived cells (HSFc) compared to that in normal tissue. Then, the inhibitory effect of DCN on collagen synthesis was confirmed in Fc and HSFc via the detection of fibrosis markers such as COL-1 and COL-3 after the overexpression and knockdown of DCN. Moreover, functional assessments revealed that DCN suppresses the proliferation, migration and invasion of HSFc. We discovered that DCN significantly inhibits the TGF-ß1/Smad3 pathway by suppressing TGF-ß1 expression, as well as the formation and phosphorylation of Smad3. This finding suggested that DCN regulates the synthesis of collagen-based extracellular matrix and fibrosis through the TGF-ß1/Smad3 pathway.

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 effects of TGF-ß1 and IFN-α2b on decorin, decorin isoforms and type I collagen in hypertrophic scar dermal fibroblasts.

Hypertrophic scars (HTS) develop from an excessive synthesis of structural proteins like collagen and a decreased expression of proteoglycans such as decorin. Previous research has demonstrated that decorin expression is significantly down-regulated in HTS, deep dermal tissue, and thermally injured tissue, reducing its ability to regulate pro-fibrotic transforming growth factor-beta 1 (TGF-ß1) and normal fibrillogenesis. However, treatment of HTS fibroblasts with interferon-alpha 2b (IFN-α2b) has been shown to reduce excessive collagen synthesis and improve HTS by reducing serum TGF-ß1 levels. The expression of decorin isoforms in HTS is currently unknown and the effects of TGF-ß1 and IFN-α2b on decorin, decorin isoform expression and type 1 collagen are of great interest to our group. Dermal fibroblasts were treated with TGF-ß1 and/or IFN-α2b, for 48 h. The expression and secretion of decorin, decorin isoforms and type 1 collagen were quantified with reverse transcription-quantitative polymerase chain reaction, immunofluorescence staining and enzyme-linked immunosorbent assays. The mRNA expression of decorin and each isoform was significantly reduced in HTS fibroblasts relative to normal skin. TGF-ß1 decreased the mRNA expression of decorin and decorin isoforms, whereas IFN-α2b showed the opposite effect. IFN-α2b significantly inhibited TGF-ß1's effect on the mRNA expression of type I collagen alpha 1 in papillary dermal fibroblasts and overall showed relative effects of inhibiting TGF-ß1. These data support that a further investigation into the structural and functional roles of decorin isoforms in HTS pathogenesis is warranted and that IFN-α2b is an important agent in reducing fibrotic outcomes.

OncomiR-181a promotes carcinogenesis by repressing the extracellular matrix proteoglycan decorin in hepatocellular carcinoma.

BACKGROUND: Proteoglycans are important tumor microenvironment extracellular matrix components. The regulation of key proteoglycans, such as decorin (DCN), by miRNAs has drawn attention since they have surfaced as novel therapeutic targets in cancer. Accordingly, this study aimed at identifying the impact of miR-181a in liver cancer and its regulatory role on the extracellular matrix proteoglycan, DCN, and hence on downstream oncogenes and tumor suppressor genes. RESULTS: DCN was under-expressed in 22 cirrhotic and HCC liver tissues compared to that in 11 healthy tissues of liver transplantation donors. Conversely, miR-181a was over-expressed in HCC liver tissues compared to that in healthy liver tissues. In silico analysis predicted that DCN 3'UTR harbors two high-score oncomiR-181a binding regions. This was validated by pmiRGLO luciferase reporter assay. Ectopic miR-181a expression into HuH-7 cells repressed the transcript and protein levels of DCN as assessed fluorometrically and by western blotting. DCN siRNAs showed similar results to miR-181a, where they both enhanced the cellular viability, proliferation, and clonogenicity. They also increased Myc and E2F and decreased p53 and Rb signaling as assessed using reporter vectors harboring p53, Rb, Myc, and E2F response elements. Our findings demonstrated that miR-181a directly downregulated the expression of its direct downstream target DCN, which in turn affected downstream targets related to cellular proliferation and apoptosis. CONCLUSION: To our knowledge, this is the first study to unveil the direct targeting of DCN by oncomiR-181a. We also highlighted that miR-181a affects targets related to cellular proliferation in HCC which may be partly mediated through inhibition of DCN transcription. Thus, miR-181a could be a promising biomarker for the early detection and monitoring of liver cancer progression. This would pave the way for the future targeting of the oncomiR-181a as a therapeutic approach in liver cancer, where miR-181a-based therapy approach could be potentially combined with chemotherapy and immunotherapy for the management of liver cancer.

RBM15 Knockdown Impairs the Malignancy of Cervical Cancer by Mediating m6A Modification of Decorin.

Cervical cancer (CC) is considered to be the most prevalent female malignancies across the globe and a prime cause of mortality among women. RNA-binding motif protein 15 (RBM15) has been elucidated to participate in tumorigenesis in various cancers by regulating RNA N6-methyladenosine (m6A) methylation. However, its significance and detailed molecular mechanisms remain uncertain in CC. Using CGA database and qRT-PCR, the RBM15 expression was found to be elevated in CC tissues. After performing EdU, wound healing, Transwell migration, and xenograft tumor assays, RBM15 knockdown inhibited the malignant properties of CC cells along with the tumor development of CC cells in vivo. Moreover, qRT-PCR, MeRIP, and western blotting experiments were also confirmed that decorin (DCN) downregulated in CC was a direct substrate of RBM15 m6A methylation, and RBM15 knockdown could enhance DCN expression in CC cells. The anti-tumor effects of RBM15 knockdown could be abolished by DCN silencing. Overall, RBM15 knockdown lowered the tumorigenesis of CC both in vitro and in vivo, and it does so via mediating m6A modification of DCN mRNA in CC cells.

Differential Proteoglycan Expression in Atherosclerosis Alters Platelet Adhesion and Activation.

Proteoglycans are differentially expressed in different atherosclerotic plaque phenotypes, with biglycan and decorin characteristic of ruptured plaques and versican and hyaluronan more prominent in eroded plaques. Following plaque disruption, the exposure of extracellular matrix (ECM) proteins triggers platelet adhesion and thrombus formation. In this study, the impact of differential plaque composition on platelet function and thrombus formation was investigated. Platelet adhesion, activation and thrombus formation under different shear stress conditions were assessed in response to individual proteoglycans and composites representing different plaque phenotypes. The results demonstrated that all the proteoglycans tested mediated platelet adhesion but not platelet activation, and the extent of adhesion observed was significantly lower than that observed with type I and type III collagens. Thrombus formation upon the rupture and erosion ECM composites was significantly reduced (p < 0.05) compared to relevant collagen alone, indicating that proteoglycans negatively regulate platelet collagen responses. This was supported by results demonstrating that the addition of soluble biglycan or decorin to whole blood markedly reduced thrombus formation on type I collagen (p < 0.05). Interestingly, thrombus formation upon the erosion composite displayed aspirin sensitivity, whereas the rupture composite was intensive to aspirin, having implications for current antiplatelet therapy regimes. In conclusion, differential platelet responses and antiplatelet efficacy are observed on ECM composites phenotypic of plaque rupture and erosion. Proteoglycans inhibit thrombus formation and may offer a novel plaque-specific approach to limit arterial thrombosis.

Alterations in the Structure, Composition, and Organization of Galactosaminoglycan-Containing Proteoglycans and Collagen Correspond to the Progressive Stages of Dupuytren's Disease.

Dupuytren's disease (DD) is a prevalent fibroproliferative disorder of the hand, shaped by genetic, epigenetic, and environmental influences. The extracellular matrix (ECM) is a complex assembly of diverse macromolecules. Alterations in the ECM's content, structure and organization can impact both normal physiological functions and pathological conditions. This study explored the content and organization of glycosaminoglycans, proteoglycans, and collagen in the ECM of patients at various stages of DD, assessing their potential as prognostic indicators. This research reveals, for the first time, relevant changes in the complexity of chondroitin/dermatan sulfate structures, specifically an increase of disaccharides containing iduronic acid residues covalently linked to either N-acetylgalactosamine 6-O-sulfated or N-acetylgalactosamine 4-O-sulfated, correlating with the disease's severity. Additionally, we noted an increase in versican expression, a high molecular weight proteoglycan, across stages I to IV, while decorin, a small leucine-rich proteoglycan, significantly diminishes as DD progresses, both confirmed by mRNA analysis and protein detection via confocal microscopy. Coherent anti-Stokes Raman scattering (CARS) microscopy further demonstrated that collagen fibril architecture in DD varies importantly with disease stages. Moreover, the urinary excretion of both hyaluronic and sulfated glycosaminoglycans markedly decreased among DD patients.Our findings indicate that specific proteoglycans with galactosaminoglycan chains and collagen arrangements could serve as biomarkers for DD progression. The reduction in glycosaminoglycan excretion suggests a systemic manifestation of the disease.

Trajectories of immune-related serum proteins and quality of life in patients with pancreatic and other periampullary cancer: the CHAMP study.

BACKGROUND: There is still a profound lack of efficient therapeutic strategies against pancreatic and other periampullary adenocarcinoma. Surgery is seldom possible, leaving palliative chemotherapy the only option for most patients. Chemotherapy treatment is however often accompanied by serious side-effects, and the identification of biomarkers for early prediction of disease and treatment-associated symptoms could help alleviate patient suffering. This study investigated the dynamic interrelationship between immune-related serum proteins, routine biomarkers, and health-related quality of life (HRQoL) factors during chemotherapy treatment of patients enrolled in the prospective, observational study Chemotherapy, Host response And Molecular dynamics in Periampullary cancer (CHAMP). METHODS: Proximity extension assay was applied to analyse 92 immune-associated proteins in longitudinal serum samples from 75 patients, 18 treated with curative and 57 with palliative intent. HRQoL data were available from all patients at baseline (BL), from 41 patients at three months, and from 23 patients at six months. Information on routine laboratory parameters albumin, CA19-9, CEA and CRP were collected from medical charts. RESULTS: In total nine proteins; chemokine (C-C motif) ligand 23 (CCL23), cluster of differentiation 4 (CD4), cluster of differentiation 28 (CD28), decorin (DCN), galectin-1 (Gal-1), granzyme B (GZMB), granzyme H (GZMH), matrix metallopeptidase 7 (MMP7), and monocyte chemotactic protein-1 (MCP-1) were strongly correlated (Spearman's Rho ≤ -0.6 or ≥ 0.6) with either cognitive functioning (DCN), emotional functioning (DCN, MCP-1), dyspnoea (CD28, GZMB, GZMH) or insomnia (CCL23, CD4, Gal-1, MMP7) during treatment. Associations between routine laboratory parameters (CA 19-9, CA-125, CRP, CEA and albumin) and HRQoL factors were overall weaker. None of the investigated proteins were associated with pain. CONCLUSIONS: This is, to our knowledge, the first study exploring associations between serum biomarkers and HRQoL in patients with pancreatic or other periampullary cancer, and some findings merit further validation. The associations of DCN and MCP-1with impaired cognitive and/or emotional functioning are of particular interest, given their established link to various neurodegenerative conditions. Chemotherapy is known to cause persistent cognitive dysfunction with effects on memory and executive function, referred to as "chemo brain". It would therefore be of great value to identify biomarkers for early detection and management of this debilitating condition. TRIAL REGISTRATION: Clinical Trial Registration: NCT03724994.

Hyperprolactinemia modifies extracellular matrix components associated with collagen fibrillogenesis in harderian glands of non- and pregnant female mice.

The harderian gland (HG) is a gland located at the base of the nictating membrane and fills the inferomedial aspect of the orbit in rodents. It is under the influence of the hypothalamic-pituitary-gonadal axis and, because of its hormone receptors, it is a target tissue for prolactin (PRL) and sex steroid hormones (estrogen and progesterone). In humans and murine, the anterior surface of the eyes is protected by a tear film synthesized by glands associated with the eye. In order to understand the endocrine changes caused by hyperprolactinemia in the glands responsible for the formation of the tear film, we used an animal model with metoclopramide-induced hyperprolactinemia (HPRL). Given the evidences that HPRL can lead to a process of cell death and tissue fibrosis, the protein expression of small leucine-rich proteoglycans (SLRPs) was analyzed through immunohistochemistry in the HG of the non- and the pregnant female mice with hyperprolactinemia. The SRLPs are related to collagen fibrillogenesis and they participate in pro-apoptotic signals. Our data revealed that high prolactin levels and changes in steroid hormones (estrogen and progesterone) can lead to an alteration in the amount of collagen, and in the structure of type I and III collagen fibers through changes in the amounts of lumican and decorin, which are responsible for collagen fibrillogenesis. This fact can lead to the impaired functioning of the HG by excessive apoptosis in the HG of the non- and the pregnant female mice with HPRL and especially in the HG of pregnancy-associated hyperprolactinemia.

Relationship of biglycan and decorin expression with clinicopathological features and prognosis in patients with oral squamous cell carcinoma.

OBJECTIVE: This study focused on investigating relation between biglycan (BGN) and decorin (DCN) expression and prognostic outcome for oral squamous cell carcinoma (OSCC) cases. MATERIAL AND METHODS: BGN and DCN mRNA and protein expression was detected by qRT-PCR and Western-blotting (WB) assays from 31 OSCC samples as well as healthy samples. This work harvested 101 paraffin-embedded OSCC together with 30 healthy samples, and conducted immunohistochemical (IHC) staining for assessing pathological changes. Association of DCN with BGN within OSCC was explored by Spearman's analysis. Survival rate was explored by Kaplan-Meier (KM) approach. Multivariate analysis was conducted by Cox regression. RESULTS: WB and qRT-PCR results showed BGN up-regulation (p < 0.001, p < 0.0001) whereas DCN down-regulation (p < 0.0001, p < 0.0001) with fresh OSCC tissues; the expression of BGN and DCN associated with the OSCC histopathological grade. IHC results suggested elevated BGN level (p < 0.0001) whereas DCN down-regulation (p < 0.0001) with paraffin embedded OSCC tissues. The expression of BGN and DCN associated with histopathologic grades and tumor stage of OSCC. The result of Spearman's analysis demonstrated significant association between the expression of BGN and DCN in OSCC. Survival analysis revealed that patients with higher BGN/lower DCN level showed poor overall survival (OS) as well as tumor-specific survival (TSS). Multivariate analysis proved that BGN and DCN independently predicted the prognosis of OS and TSS. CONCLUSION: BGN and DCN expression levels can be adopted for predicting OSCC prognostic outcome.

Decorin inhibits the formation of hard nodules after microwave ablation by inhibiting the TGF-ß1/SMAD and MAPK signaling pathways: in a Bama miniature pig model of mammary gland hyperplasia.

BACKGROUND: Benign breast lesions are often associated with hard nodule formation after microwave ablation (MWA), which persists for a long time and causes problems in patients. The aim of this study was to evaluate the efficacy of decorin in the treatment of hard nodule formation and its potential mechanism of action. METHODS: Using a Bama miniature pig model of mammary gland hyperplasia, immunohistochemistry, Masson's trichrome and western blotting were firstly applied to compare the extent of fibrosis and activation of key members of the TGF-ß1/SMAD and MAPK signaling pathways of hard nodule in the control and MWA groups, and then the extent of fibrosis and expression of signaling pathways in hard nodule were examined after application of decorin. RESULTS: The results showed that the MWA group had increased levels of TGF-ß1, p-SMAD2/3, p-ERK1/2, and collagen I proteins and increased fibrosis at 2 weeks, 4 weeks, and 3 months after MWA. After decorin treatment, the expression levels of each protein were significantly downregulated, and the degree of fibrosis was reduced at 2 weeks, 4 weeks, and 3 months after MWA compared with the MWA group. CONCLUSION: In conclusion, these results suggest that activation of TGF-ß1 may play an important role in hard nodule formation and that decorin may reduce hard nodule formation after MWA in a model of mammary gland hyperplasia by inhibiting the TGF-ß1/SMAD and MAPK signaling pathways.

The myokine decorin improves the cardiac function in a rat model of isoprenaline-induced myocardial infarction.

Myocardial infarction is a common cause of disability. Decorin is a myokine that has anti-inflammatory, anti-apoptotic effects. Some studies stated that decorin protects myocardium from ischemia. Other studies stated that decorin levels are associated with acute coronary syndrome. The study aimed to investigate the therapeutic role of decorin on cardiac function in a rat model of myocardial infarction. Thirty adult male Wistar rats were divided into control group-rats were subcutaneously injected with normal saline, isoprenaline-injected group-rats were subcutaneously injected with isoprenaline (85 mg/kg) once daily for 2 days to induce myocardial infarction, and decorin ± isoprenaline-injected group-rats were injected as the previous group, followed by decorin injection (0.1 mg/kg) once daily for 7 days. Cardiac hemodynamics, serum lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), oxidative stress markers, gene expression for myocardial-transforming growth factor beta 1 (TGF-ß1), interleukin 1 b (IL-1ß), tumor necrosis factor alpha (TNF-α), and cardiac caspase-3 immunohistochemical analysis were done. Isoprenaline + decorin group had significant improvement in cardiac hemodynamics and oxidative stress markers; significant decrease in serum CK-MB, LDH, and myocardial gene expression for TNF-α, IL-1ß, and TGF-ß1; and decreased cardiac caspase-3 immunoreactivity was present. Therefore, decorin can be used as a therapeutic agent after myocardial infarction as it improved the cardiac function.

Nanomechanics of Aggrecan: A New Perspective on Cartilage Biomechanics, Disease and Regeneration.

Articular cartilage is a hydrated macromolecular composite mainly composed of type II collagen fibrils and the large proteoglycan, aggrecan. Aggrecan is a key determinant of the load bearing and energy dissipation functions of cartilage. Previously, studies of cartilage biomechanics have been primarily focusing on the macroscopic, tissue-level properties, which failed to elucidate the molecular-level activities that govern cartilage development, function, and disease. This chapter provides a brief summary of Dr. Alan J. Grodzinsky's seminal contribution to the understanding of aggrecan molecular mechanics at the nanoscopic level. By developing and applying a series of atomic force microscopy (AFM)-based nanomechanical tools, Grodzinsky and colleagues revealed the unique structural and mechanical characteristics of aggrecan at unprecedented resolutions. In this body of work, the "bottle-brush"-like ultrastructure of aggrecan was directly visualized for the first time. Meanwhile, molecular mechanics of aggrecan was studied using a physiological-like 2D biomimetic assembly of aggrecan on multiple fronts, including compression, dynamic loading, shear, and adhesion. These studies not only generated new insights into the development, aging, and disease of cartilage, but established a foundation for designing and evaluating novel cartilage regeneration strategies. For example, building on the scientific foundation and methodology infrastructure established by Dr. Grodzinsky, recent studies have elucidated the roles of other proteoglycans in mediating cartilage integrity, such as decorin and perlecan, and evaluated the therapeutic potential of biomimetic proteoglycans in improving cartilage regeneration.

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

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

The aberrant levels of decorin induce damages of human salivary gland epithelial cells and polarization of macrophages.

OBJECTIVES: This study aimed to preliminarily address the levels of decorin (DCN, a critical component of extracellular matrix) and its potential roles in primary Sjögren's syndrome (pSS). METHODS: DCN levels were determined in the salivary glands of experimental SS (ESS) mice and pSS patients by RNA sequencing, bioinformatics analysis, or immunohistochemical staining. Its correlation with interested genes and co-localization with a putative receptor was studied in pSS patients. In addition, its potential roles on salivary gland epithelium and macrophages were tested by exogenous administration to corresponding cell lines, followed by the evaluation of apoptosis using flow cytometry or cytokine expression using quantitative real-time polymerase chain reaction. RESULTS: Our data revealed a significant elevation of DCN in the salivary glands of the ESS mice model and pSS patients. In addition, the bioinformatics analysis of DCN in the GSE40611 (RNA-seq, parotid glands) dataset displayed an elevation of the DCN level in the parotid glands of pSS patients that positively correlated with several chemokines (CXCL13, CXCL9, and CCL20), Interleukin -1 ß (IL1 -ß), and caspase3 but negatively correlated with the proliferation relative gene MKI67. The stimulatory effects of DCN on the salivary gland epithelial cells (A253 cell line) and macrophages have been determined as they are considered active participants in the progression of SS. The data showed that DCN induced the apoptosis of A253 cells and polarization of macrophages towards the M1 phenotype, characterized by the expression of pro-inflammatory cytokines. CONCLUSIONS: Our study provided preliminary evidence to understand the clinical significance of DCN in pSS and broadened our horizons in understanding the mechanism of pSS.

CXCR4 blockade in macrophage promotes angiogenesis in ischemic hindlimb by modulating autophagy.

Chemokine receptor CXCR4 plays a crucial role in leukocyte recruitment and inflammation regulation to influence tissue repair in ischemic diseases. Here we assessed the effect of CXCR4 expression in macrophages on angiogenesis in the ischemic hindlimb of a mouse. Inflammatory cells were increased in the ischemic muscles of hindlimb, and CXCR4 was highly expressed in the infiltrated macrophages but not in neutrophils. Myeloid-specific CXCR4 knockout attenuated macrophage infiltration and subsequent reduced inflammatory response in the ischemic hindlimb, accompanied with better blood reperfusion and higher capillary density as compared with that in LysM Cre+/- (Cre) mice. Similar outcomes were also observed in CRE mice whose bone marrow cells were replaced with those from CXCR4-deficient mice. Gene ontology cluster analysis reviewed that Decorin, a negative regulator of angiogenesis, was reduced in CXCR4-deficient macrophages. CXCR4-deficient macrophages were less inducible into M1 phase by lipopolysaccharide and more favorable for M2 polarization under oxygen/glucose deprivation condition. Enhanced autophagy was detected in CXCR4-deficient macrophages, which was associated with less expression of both Decorin and the inflammatory cytokines. In summary, myeloid-specific CXCR4 deficiency reduced monocyte infiltration and the secretion of inflammatory cytokines and Decorin from macrophages, thus blunting inflammation response and promoting angiogenesis in the ischemic hindlimb.

Decorin evokes reversible mitochondrial depolarization in carcinoma and vascular endothelial cells.

Decorin, a small leucine-rich proteoglycan with multiple biological functions, is known to evoke autophagy and mitophagy in both endothelial and cancer cells. Here, we investigated the effects of soluble decorin on mitochondrial homeostasis using live cell imaging and ex vivo angiogenic assays. We discovered that decorin triggers mitochondrial depolarization in triple-negative breast carcinoma, HeLa, and endothelial cells. This bioactivity was mediated by the protein core in a time- and dose-dependent manner and was specific for decorin insofar as biglycan, the closest homolog, failed to trigger depolarization. Mechanistically, we found that the bioactivity of decorin to promote depolarization required the MET receptor and its tyrosine kinase. Moreover, two mitochondrial interacting proteins, mitostatin and mitofusin 2, were essential for downstream decorin effects. Finally, we found that decorin relied on the canonical mitochondrial permeability transition pore to trigger tumor cell mitochondrial depolarization. Collectively, our study implicates decorin as a soluble outside-in regulator of mitochondrial dynamics.

Alterations in glycosaminoglycan biosynthesis associated with the Ehlers-Danlos syndromes.

Proteoglycans consist of a core protein substituted with one or more glycosaminoglycan (GAG) chains and execute versatile functions during many physiological and pathological processes. The biosynthesis of GAG chains is a complex process that depends on the concerted action of a variety of enzymes. Central to the biosynthesis of heparan sulfate (HS) and chondroitin sulfate/dermatan sulfate (CS/DS) GAG chains is the formation of a tetrasaccharide linker region followed by biosynthesis of HS or CS/DS-specific repeating disaccharide units, which then undergo modifications and epimerization. The importance of these biosynthetic enzymes is illustrated by several severe pleiotropic disorders that arise upon their deficiency. The Ehlers-Danlos syndromes (EDS) constitute a special group among these disorders. Although most EDS types are caused by defects in fibrillar types I, III, or V collagen, or their modifying enzymes, a few rare EDS types have recently been linked to defects in GAG biosynthesis. Spondylodysplastic EDS (spEDS) is caused by defective formation of the tetrasaccharide linker region, either due to ß4GalT7 or ß3GalT6 deficiency, whereas musculocontractural EDS (mcEDS) results from deficiency of D4ST1 or DS-epi1, impairing DS formation. This narrative review highlights the consequences of GAG deficiency in these specific EDS types, summarizes the associated phenotypic features and the molecular spectrum of reported pathogenic variants, and defines the current knowledge on the underlying pathophysiological mechanisms based on studies in patient-derived material, in vitro analyses, and animal models.

Conserved lysine residues in decorin binding proteins of Borrelia garinii are critical in adhesion to human brain microvascular endothelial cells.

Lyme borreliosis is a tick-borne disease caused by Borrelia burgdorferi sensu lato spirochetes (Lyme borreliae). When the disease affects the central nervous system, it is referred to as neuroborreliosis. In Europe, neuroborreliosis is most often caused by Borrelia garinii. Although it is known that in the host Lyme borreliae spread from the tick bite site to distant tissues via the blood vasculature, the adherence of Lyme borreliae to human brain microvascular endothelial cells has not been studied before. Decorin binding proteins are adhesins expressed on Lyme borreliae. They mediate the adhesion of Lyme borreliae to decorin and biglycan, and the lysine residues located in the binding site of decorin binding proteins are important to the binding activity. In this study, we show that lysine residues located in the canonical binding site can also be found in decorin binding proteins of Borrelia garinii, and that these lysines contribute to biglycan and decorin binding. Most importantly, we show that the lysine residues are crucial for the binding of Lyme borreliae to decorin and biglycan expressing human brain microvascular endothelial cells, which in turn suggests that they are involved in the pathogenesis of neuroborreliosis.

Mild heat stimulation facilitates muscle hypertrophy in C2C12 and mouse satellite cells through myokine release to the culture medium.

Mild heat stimulation is defined as a stimulation that occurs several degrees above optimal cell culture or body temperatures. Muscle hypertrophy in C2C12 cells is reportedly facilitated by 39 °C mild heat stimulation. However, the underlying molecular mechanisms by which 39 °C mild heat stimulation promotes muscle hypertrophy remains elusive. In this study, we aimed at understanding the details of these mechanisms. First, we found that 39 °C mild heat stimulation has little or no effect on Myogenesis-Related Factor (MRF) expression both in C2C12 and mouse primary satellite cells. Therefore, we hypothesized that 39 °C mild heat stimulation promotes muscle hypertrophy through myokines, essential components in myogenesis. Interestingly, we observed muscle hypertrophy in the group cultured at 37 °C in conditioned medium from 39 °C compared to the group cultured at 37 °C in conditioned medium from 37 °C in the case of both C2C12 and mouse primary satellite cells. These results suggest that 39 °C mild heat stimulation promotes muscle hypertrophy through myokines, once released in the culture medium. Finally, we identified Decorin as a hypertrophy-inducing myokine candidate. Therefore, in this study, we demonstrated that 39 °C mild heat stimulation contributes to muscle hypertrophy through enhancing Decorin gene expression in C2C12 and mouse primary satellite cells.