Central role of thrombospondin-1 in the activation and clonal expansion of inflammatory T cells

Thrombospondin-1 associated with carotid intima-media thickness among individuals with hypertension

In vivo and in vitro studies have demonstrated that thrombospondin-1 (TSP-1) is involved in atherosclerotic pathogenesis. However, the role of TSP-1 in clinical atherosclerosis remains unknown. This cross-sectional study investigated the relationship between TSP-1 and carotid intima-media thickness (IMT) and examined whether it interacts with conventional cardiovascular risk factors. A total of 587 participants were enrolled from February 2018 to December 2021. TSP-1 was dichotomized based on median value. Carotid IMT was measured bilaterally in each segment, and the average value was taken as the overall IMT variable. Analysis of covariance models were used to ascertain the main and interaction effects of cardiovascular risk factors and circulating TSP-1 levels on carotid IMT. Those with high TSP-1 (n = 294) had significantly higher carotid IMT than did those with low TSP-1 (n = 293; 0.74 ± 0.12 vs 0.72 ± 0.11 mm; p = 0.011). After the combined effects of TSP-1 and vascular risk factors on carotid IMT were evaluated, an interaction effect on IMT was observed between TSP-1 and hypertension (adjusted F = 8.760; p = 0.003). Stratification analysis revealed that individuals with hypertension and high TSP-1 had significantly higher IMT than did those with low TSP-1 (adjusted p = 0.007). However, this difference was not observed in normotensive individuals (adjusted p = 0.636). In conclusion, this is the first study to provide clinical data supporting the correlation between TSP-1 and atherosclerosis. TSP-1 may be a crucial marker of increased susceptibility to atherosclerosis in individuals with hypertension.

Methylation and transcriptomic expression profiles of HUVEC in the oxygen and glucose deprivation model and its clinical implications in AMI patients

The obstructed coronary artery undergoes a series of pathological changes due to ischemic-hypoxic shocks during acute myocardial infarction (AMI). However, the altered DNA methylation levels in endothelial cells under these conditions and their implication for the etiopathology of AMI have not been investigated in detail. This study aimed to explore the relationship between DNA methylation and pathologically altered gene expression profile in human umbilical vein endothelial cells (HUVECs) subjected to oxygen-glucose deprivation (OGD), and its clinical implications in AMI patients. The Illumina Infinium MethylationEPIC BeadChip assay was used to explore the genome-wide DNA methylation profile using the Novaseq6000 platform for mRNA sequencing in 3 pairs of HUVEC-OGD and control samples. GO and KEGG pathway enrichment analyses, as well as correlation, causal inference test (CIT), and protein-protein interaction (PPI) analyses identified 22 hub genes that were validated by MethylTarget sequencing as well as qRT-PCR. ELISA was used to detect four target molecules associated with the progression of AMI. A total of 2,524 differentially expressed genes (DEGs) and 22,148 differentially methylated positions (DMPs) corresponding to 6,642 differentially methylated genes (DMGs) were screened (|Δβ|>0.1 and detection p < 0.05). After GO, KEGG, correlation, CIT, and PPI analyses, 441 genes were filtered. qRT-PCR confirmed the overexpression of VEGFA, CCL2, TSP-1, SQSTM1, BCL2L11, and TIMP3 genes, and downregulation of MYC, CD44, BDNF, GNAQ, RUNX1, ETS1, NGFR, MME, SEMA6A, GNAI1, IFIT1, and MEIS1. DNA fragments BDNF_1_ (r = 0.931, p < 0.0001) and SQSTM1_2_NEW (r = 0.758, p = 0.0043) were positively correlated with the expressions of corresponding genes, and MYC_1_ (r = -0.8245, p = 0.001) was negatively correlated. Furthermore, ELISA confirmed TNFSF10 and BDNF were elevated in the peripheral blood of AMI patients (p = 0.0284 and p = 0.0142, respectively). Combined sequencing from in vitro cellular assays with clinical samples, aiming to establish the potential causal chain of the causal factor (DNA methylation) - mediator (mRNA)-cell outcome (endothelial cell ischemic-hypoxic injury)-clinical outcome (AMI), our study identified promising OGD-specific genes, which provided a solid basis for screening fundamental diagnostic and prognostic biomarkers of coronary endothelial cell injury of AMI. Moreover, it furnished the first evidence that during ischemia and hypoxia, the expression of BNDF was regulated by DNA methylation in endothelial cells and elevated in peripheral blood.

CXCL9 recombinant adeno-associated virus (AAV) virotherapy sensitizes glioblastoma (GBM) to anti-PD-1 immune checkpoint blockade

The promise of immunotherapy to induce long-term durable responses in conventionally treatment resistant tumors like glioblastoma (GBM) has given hope for patients with a dismal prognosis. Yet, few patients have demonstrated a significant survival benefit despite multiple clinical trials designed to invigorate immune recognition and tumor eradication. Insights gathered over the last two decades have revealed numerous mechanisms by which glioma cells resist conventional therapy and evade immunological detection, underscoring the need for strategic combinatorial treatments as necessary to achieve appreciable therapeutic effects. However, new combination therapies are inherently difficult to develop as a result of dose-limiting toxicities, the constraints of the blood-brain barrier, and the suppressive nature of the GBM tumor microenvironment (TME). GBM is notoriously devoid of lymphocytes driven in part by a paucity of lymphocyte trafficking factors necessary to prompt their recruitment, infiltration, and activation. We have developed a novel recombinant adeno-associated virus (AAV) gene therapy strategy that enables focal and stable reconstitution of the GBM TME with C-X-C motif ligand 9 (CXCL9), a powerful call-and-receive chemokine for cytotoxic T lymphocytes (CTLs). By precisely manipulating local chemokine directional guidance, AAV-CXCL9 increases tumor infiltration by CD8-postive cytotoxic lymphocytes, sensitizing GBM to anti-PD-1 immune checkpoint blockade (ICB). These effects are accompanied by immunologic signatures evocative of an inflamed and responsive TME. These findings support targeted AAV gene therapy as a promising adjuvant strategy for reconditioning GBM immunogenicity given its excellent safety profile, TME-tropism, modularity, and off-the-shelf capability, where focal delivery bypasses the constrains of the blood-brain barrier, further mitigating risks observed with high-dose systemic therapy.

Controlled extracellular proteolysis of thrombospondins

Limited proteolysis of thrombospondins is a powerful mechanism to ensure dynamic tuning of their activities in the extracellular space. Thrombospondins are multifunctional matricellular proteins composed of multiple domains, each with a specific pattern of interactions with cell receptors, matrix components and soluble factors (growth factors, cytokines and proteases), thus with different effects on cell behavior and responses to changes in the microenvironment. Therefore, the proteolytic degradation of thrombospondins has multiple functional consequences, reflecting the local release of active fragments and isolated domains, exposure or disruption of active sequences, altered protein location, and changes in the composition and function of TSP-based pericellular interaction networks. In this review current data from the literature and databases is employed to provide an overview of cleavage of mammalian thrombospondins by different proteases. The roles of the fragments generated in specific pathological settings, with particular focus on cancer and the tumor microenvironment, are discussed.

Unbiased proteomic analysis of extracellular vesicles secreted by senescent human vascular smooth muscle cells reveals their ability to modulate immune cell functions

Atherosclerosis, a common age-related disease, is characterized by intense immunological activity. Atherosclerotic plaque is composed of endothelial cells, vascular smooth muscle cells (VSMCs), lipids and immune cells infiltrating from the blood. During progression of the disease, VSMCs undergo senescence within the plaque and secrete SASP (senescence-associated secretory phenotype) factors that can actively modulate plaque microenvironment. We demonstrated that senescent VSMCs secrete increased number of extracellular vesicles (senEVs). Based on unbiased proteomic analysis of VMSC-derived EVs and of the soluble fraction of SASP (sSASP), more than 900 proteins were identified in each of SASP compartments. Comparison of the composition of VMSC-derived EVs with the SASP atlas revealed several proteins, including Serpin Family F Member 1 (SERPINF1) and Thrombospondin 1 (THBS1), as commonly upregulated components of EVs secreted by senescent VSMCs and fibroblasts. Among soluble SASP factors, only Growth Differentiation Factor 15 (GDF15) was universally increased in the secretome of senescent VSMCs, fibroblasts, and epithelial cells. Bioinformatics analysis of EV proteins distinguished functionally organized protein networks involved in immune cell function regulation. Accordingly, EVs released by senescent VSMCs induced secretion of IL-17, INFγ, and IL-10 by T cells and of TNFα produced by monocytes. Moreover senEVs influenced differentiation of monocytes favoring mix M1/M2 polarization with proinflammatory characteristics. Altogether, our studies provide a complex, unbiased analysis of VSMC SASP and prove that EVs derived from senescent VSMCs influence the cytokine milieu by modulating immune cell activity. Our results strengthen the role of senescent cells as an important inducer of inflammation in atherosclerosis.

Discrete Correlation Summation Clustering Reveals Differential Regulation of Liver Metabolism by Thrombospondin-1 in Low-Fat and High-Fat Diet-Fed Mice

Thrombospondin-1 (TSP1) is a matricellular protein with many important roles in mediating carcinogenesis, fibrosis, leukocyte recruitment, and metabolism. We have previously shown a role of diet in the absence of TSP1 in liver metabolism in the context of a colorectal cancer model. However, the metabolic implications of TSP1 regulation by diet in the liver metabolism are currently understudied. Therefore Discrete correlation summation (DCS) was used to re-interrogate data and determine the metabolic alterations of TSP1 deficiency in the liver, providing new insights into the role of TSP1 in liver injury and the progression of liver pathologies such as nonalcoholic fatty liver disease (NAFLD). DCS analysis provides a straightforward approach to rank covariance and data clustering when analyzing complex data sets. Using this approach, our previous liver metabolite data was re-analyzed by comparing wild-type (WT) and Thrombospondin-1 null (Thbs1-/-) mice, identifying changes driven by genotype and diet. Principal component analysis showed clustering of animals by genotype regardless of diet, indicating that TSP1 deficiency alters metabolite handling in the liver. High-fat diet consumption significantly altered over 150 metabolites in the Thbs1-/- livers versus approximately 90 in the wild-type livers, most involved in amino acid metabolism. The absence of Thbs1 differentially regulated tryptophan and tricarboxylic acid cycle metabolites implicated in the progression of NAFLD. Overall, the lack of Thbs1 caused a significant shift in liver metabolism with potential implications for liver injury and the progression of NAFLD.

Two Main Cellular Components in Rheumatoid Arthritis: Communication Between T Cells and Fibroblast-Like Synoviocytes in the Joint Synovium

Rheumatoid arthritis (RA) is a chronic autoimmune disease that endangers the health of approximately 1% of the global population. Current RA medications on the market mainly include non-steroidal anti-inflammatory drugs, biological agents, and disease-modifying drugs. These drugs aim to inhibit the overactivated immune response or inflammation of RA, but they cannot cure RA. A better understanding of the pathogenesis of RA will provide a new understanding to search for RA targets and for drug development. The infiltration of T cells and hyper-proliferation of fibroblast-like synoviocytes (FLS) in the synovium of patients with RA are significantly upregulated. Furthermore, the abnormal activation of these two types of cells has been confirmed to promote development of the course of A by many studies. This article systematically summarizes the interactions between T cells and FLS in RA synovial tissues, including one-way/mutual regulation and direct/indirect regulation between the two. It further aims to investigate the pathogenesis of RA from the perspective of mutual regulation between T cells and FLS and to provide new insights into RA research.

MYC oncogene is associated with suppression of tumor immunity and targeting Myc induces tumor cell immunogenicity for therapeutic whole cell vaccination

Background

MYC oncogene is deregulated in 70% of all human cancers and is associated with multiple oncogenic functions including immunosuppression in the tumor microenvironment. The role of MYC in the immune microenvironment of neuroblastoma and melanoma is investigated and the effect of targeting Myc on immunogenicity of cancer cells is evaluated.

Methods

Immune cell infiltrates and immunogenic pathway signatures in the context of MYCN amplification were analyzed in human neuroblastoma tumors and in metastatic melanoma. Dose response and cell susceptibility to MYC inhibitors (I-BET726 and JQ1) were determined in mouse cell lines. The influence of downregulating Myc in tumor cells was characterized by immunogenic pathway signatures and functional assays. Myc-suppressed tumor cells were used as whole cell vaccines in preclinical neuroblastoma and melanoma models.

Results

Analysis of immune phenotype in human neuroblastoma and melanoma tumors revealed that MYCN or c-MYC amplified tumors respectively are associated with suppressed immune cell infiltrates and functional pathways. Targeting Myc in cancer cells with I-BET726 and JQ1 results in cell cycle arrest and induces cell immunogenicity. Combining vaccination of Myc-inhibited tumor cells with checkpoint inhibition induced robust antitumor immunity and resulted in therapeutic cancer vaccine therapy in mouse neuroblastoma tumors. Despite vigorous antitumor immunity in the mouse melanoma model, upregulation of immunosuppressive pathways enabled tumor escape.

Conclusions

This study demonstrates that the Myc oncogene is an appropriate target for inducing tumor cell immunogenicity and suggests that Myc-suppressed whole tumor cells combined with checkpoint therapy could be used for formulating a personalized therapeutic tumor vaccine.

Thrombospondin-1 as a Potential Therapeutic Target: Multiple Roles in Cancers

Thrombospondin-1, an extracellular matrix protein, is the first identified natural angiogenesis inhibitor. Thrombospondin-1 participates in a great number of physiological and pathological processes, including cell-cell and cell-matrix interactions via a number of cell receptors, including CD36 and CD47, which plays a vital role in mediating inflammation and performs a promoting effect in pulmonary arterial vasculopathy and diabetes. Thrombospondin-1 consists of six domains, which combine with different molecules and participate in various functions in cancers, serving as a critical member in diverse pathways in cancers. Thrombospondin-1 works as a cancer promotor in some pathways but as a cancer suppressor in others, which makes it highly possible that its erroneous functioning might lead to opposite effects. Therefore, subdividing the roles of thrombospondin-1 and distinguishing them in cancers are necessary. Complex structure and multiple roles take disadvantage of the research and application of thrombospondin-1. Compared with the whole thrombospondin-1 protein, each thrombospondin- 1 active peptide performs an uncomplicated structure and, nevertheless, a specific role. In other words, various thrombospondin-1 active peptides may function differently. For instance, thrombospondin-1 could both promote and inhibit glioblastoma, which is significantly inhibited by the three type I repeats, a thrombospondin-1 active peptide but promoted by the fragment 167-569, a thrombospondin-1 active peptide consisting of the procollagen homology domain and the three type I repeats. Further studies of the functions of thrombospondin-1 active peptides and applying them reasonably are necessary. In addition to mediating cancerogenesis, thrombospondin-1 is also affected by cancer development, as reflected by its expression in plasma and the cancer tissue. Therefore, thrombospondin-1 may be a potential biomarker for pre-clinical and clinical application. This review summarizes findings on the multiple roles of thrombospondin-1 in cancer processes, with a focus on its use as a potential therapeutic target.

Immunobiology of Inherited Muscular Dystrophies

The immune response to acute muscle damage is important for normal repair. However, in chronic diseases such as many muscular dystrophies, the immune response can amplify pathology and play a major role in determining disease severity. Muscular dystrophies are inheritable diseases that vary tremendously in severity, but share the progressive loss of muscle mass and function that can be debilitating and lethal. Mutations in diverse genes cause muscular dystrophy, including genes that encode proteins that maintain membrane strength, participate in membrane repair, or are components of the extracellular matrix or the nuclear envelope. In this article, we explore the hypothesis that an important feature of many muscular dystrophies is an immune response adapted to acute, infrequent muscle damage that is misapplied in the context of chronic injury. We discuss the involvement of the immune system in the most common muscular dystrophy, Duchenne muscular dystrophy, and show that the immune system influences muscle death and fibrosis as disease progresses. We then present information on immune cell function in other muscular dystrophies and show that for many muscular dystrophies, release of cytosolic proteins into the extracellular space may provide an initial signal, leading to an immune response that is typically dominated by macrophages, neutrophils, helper T-lymphocytes, and cytotoxic T-lymphocytes. Although those features are similar in many muscular dystrophies, each muscular dystrophy shows distinguishing features in the magnitude and type of inflammatory response. These differences indicate that there are disease-specific immunomodulatory molecules that determine response to muscle cell damage caused by diverse genetic mutations. © 2018 American Physiological Society. Compr Physiol 8:1313-1356, 2018.

Thrombospondin-1 Production Regulates the Inflammatory Cytokine Secretion in THP-1 Cells Through NF-κB Signaling Pathway

Thrombospondin-1 (TSP-1) is upregulated in several inflammatory diseases. Recent data have shown that macrophages from TSP-1-deficient mice have a reduced inflammatory phenotype, suggesting that TSP-1 plays a part in macrophage activation. DNA microarray approach revealed that Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) may induce the enhanced TSP-1 expression in human monocytes, suggesting a role of TSP-1-mediated pathogenesis in periodontitis. Until recently, the function of TSP-1 has been a matter of debate. In this study, we explored the role of TSP-1 in inflammatory cytokine secretions and its putative mechanism in pathogenesis of periodontitis. We demonstrated that TSP-1 expression was significantly upregulated in gingival tissues with periodontitis and in P. gingivalis LPS-stimulated THP-1 cells. Deficiency of TSP-1 by transfecting siRNAs decreased IL-6, IL-1β, and TNF-α secretions in THP-1 cells, whereas overexpression of TSP-1 resulted in an upregulation of IL-6, IL-1β, and TNF-α productions. Additional experiments showed that Pyrrolidine dithiocarbamate (PDTC) inhibited IL-6, IL-1β, and TNF-α expression induced by overexpression of TSP-1, accompanying with downregulation of phosphorylated p65 and IκBα protein levels in response to P. gingivalis LPS. These results indicated that TSP-1 played a significant role in P. gingivalis LPS-initiated inflammatory cytokines (IL-6, IL-1β, and TNF-α) secretions of THP-1 cells, and the NF-κB signaling is involved in its induction of expression. Thus, TSP-1 effectively elevated P. gingivalis LPS-induced inflammation mediated by the NF-κB pathway and may be critical for pathology of periodontitis.

Host mechanisms involved in cattle Escherichia coli O157 shedding: a fundamental understanding for reducing foodborne pathogen in food animal production

The host mechanisms involved in Escherichia coli O157 super-shedding in cattle is largely unknown. In this study, the comparison of transcriptomes of intestinal tissues between super-shedders (SS) and cattle negative for E. coli O157 (NS) was performed, aiming to identify genes that are potentially associated with super-shedding. In total, 16,846 ± 639 (cecum) to 18,137 ± 696 (distal jejunum) were expressed throughout the intestine, with the expressed genes associated with immune functions more pronounced in the small intestine. In total, 351 differentially expressed (DE) genes were identified throughout the intestine between SS and NS, with 101 being up-regulated and 250 down-regulated in SS. Functional analysis revealed DE genes were involved in increased T-cell responses and cholesterol absorption in the distal jejunum and descending colon, and decreased B-cell maturation in the distal jejunum of SS. RNA-Seq based SNP discovery revealed that the mutations in seven DE genes involved in leukocyte activation and cholesterol transportation were associated with E. coli O157 shedding. Our findings suggest that T-cell responses and cholesterol metabolism in the intestinal tract may be associated with super-shedding phenomenon, and the SNPs in the DE genes are possibly associated with the observed gene expression difference between SS and NS.

Immune and myodegenerative pathomechanisms in inclusion body myositis

Inclusion Body Myositis (IBM) is a relatively common acquired inflammatory myopathy in patients above 50 years of age. Pathological hallmarks of IBM are intramyofiber protein inclusions and endomysial inflammation, indicating that both myodegenerative and inflammatory mechanisms contribute to its pathogenesis. Impaired protein degradation by the autophagic machinery, which regulates innate and adaptive immune responses, in skeletal muscle fibers has recently been identified as a potential key pathomechanism in IBM. Immunotherapies, which are successfully used for treating other inflammatory myopathies lack efficacy in IBM and so far no effective treatment is available. Thus, a better understanding of the mechanistic pathways underlying progressive muscle weakness and atrophy in IBM is crucial in identifying novel promising targets for therapeutic intervention. Here, we discuss recent insights into the pathomechanistic network of mutually dependent inflammatory and degenerative events during IBM.

Immune modulation of some autoimmune diseases: the critical role of macrophages and neutrophils in the innate and adaptive immunity

Macrophages and neutrophils are key components involved in the regulation of numerous chronic inflammatory diseases, infectious disorders, and especially certain autoimmune disease. However, little is known regarding the contribution of these cells to the pathogenesis of autoimmune disorders. Recent studies have aimed to clarify certain important factors affecting the immunogenicity of these cells, including the type and dose of antigen, the microenvironment of the cell-antigen encounter, and the number, subset, and phenotype of these cells, which can prevent or induce autoimmune responses. This review highlights the role of macrophage subsets and neutrophils in injured tissues, supporting their cooperation during the pathogenesis of certain autoimmune diseases.

Thrombospondin-1 and Cutaneous Melanoma

Background:

Thrombospondins (TSPs) are recognized as important glycoproteins that regulate a wide variety of cell functions and interactions. TSPs in malignant tumors can both enhance and inhibit tumor progression, invasion, and metastasis, depending on cell type, stromal interactions, and microenvironment. These proteins are potential targets for anticancer therapy.

Objective:

The aim of our article is to review the role of thrombospondin-1 (TSP1) in cutaneous melanoma.

Conclusions:

TSP1 expression is variable in melanoma cell lines and tumors. Similar to findings in other human cancers, expression of TSP1 by melanoma cells usually inhibits tumor progression via the antiangiogenic effect of TSP1. Conversely, stromal TSP1 overexpression in melanoma is a poor prognostic factor associated with decreased survival. Understanding the interactions of TSP1 with other melanoma- and matrix-associated proteins should provide new prognostic indices and possible therapeutic targets for melanoma treatment.

Secondary allergic T cell responses are regulated by dendritic cell-derived thrombospondin-1 in the setting of allergic eye disease

Allergic eye disease, as in most forms of atopy, ranges in severity among individuals from immediate hypersensitivity to a severe and debilitating chronic disease. Dendritic cells play a key role in stimulating pathogenic T cells in allergen re-exposure, or secondary responses. However, molecular cues by dendritic cells underpinning allergic T cell response levels and the impact that this control has on consequent severity of allergic disease are poorly understood. Here, we show that a deficiency in thrombospondin-1, a matricellular protein known to affect immune function, has subsequent effects on downstream T cell responses during allergy, as revealed in an established mouse model of allergic eye disease. More specifically, we demonstrate that a thrombospondin-1 deficiency specific to dendritic cells leads to heightened secondary T cell responses and consequent clinical disease. Interestingly, whereas thrombospondin-1-deficient dendritic cells augmented activity of allergen-primed T cells, this increase was not recapitulated with naïve T cells in vitro. The role of dendritic cell-derived thrombospondin-1 in regulating secondary allergic T cell responses was confirmed in vivo, as local transfer of thrombospondin-1-sufficient dendritic cells to the ocular mucosa of thrombospondin-1 null hosts prevented the development of augmented secondary T cell responses and heightened allergic eye disease clinical responses. Finally, we demonstrate that topical instillation of thrombospondin-1-derived peptide reduces T cell activity and clinical progression of allergic eye disease. Taken together, this study reveals an important modulatory role of dendritic cell-derived thrombospondin-1 on secondary allergic T cell responses and suggests the possible dysregulation of dendritic cell-derived thrombospondin-1 expression as a factor in allergic eye disease severity.

Transcriptome analysis of the effect of Vibrio alginolyticus infection on the innate immunity-related TLR5-mediated induction of cytokines in Epinephelus lanceolatus

Epinephelus lanceolatus, considered to be an aquaculture fish species of high economic value in East Asia, is one of the largest groupers in the Epinephelus genus. Vibrio alginolyticus is a bacterial species that causes high morbidity in marine fish; infection can cause exophthalmia, ulcers, septicemia, and corneal opaqueness in fish. Epinephelus lanceolatus larvae infected with Vibrio alginolyticus were subjected to transcriptome analysis to study the immune regulation pathway. Grouper larvae were injected with 2.6 × 10(4) CFU/fish in 20 μl of V. alginolyticus and control larvae were injected with TSB; RNA samples were then collected at 4, 6, 8, 10, 12, 16, 24, and 48 h after infection. Extracted RNA was subjected to reverse transcription, and used to examine the immune gene response of E. lanceolatus by Real-time PCR. Samples taken at 6 h were subjected to next-generation sequencing, resulting in a total read value of 28,705,411 and total base number of 2,152,905,850. The unigene number was 100,848, and 5913 unigenes were filtered using FPKM>0.3, 2FC, p < 0.05. Gene Ontology (GO) analysis of the filtered genes revealed a total of 30 GO numbers in the cellular component, and 58 GO numbers for both biological processes and molecular functions. Of the GO group related to immune pathways, 27 unigenes related to biological processes involving the immune response, 31 related to the immune system, 9 related to the inflammatory response, and 43 related to the response to stress were identified. KEGG pathway analysis only detected 1 to 4 genes, and as such, we selected the GO analysis results for further analysis using GeneSpring. This demonstrated that V. alginolyticus probably stimulates TLR5 activity via the bacterial flagellum, through an MyD88-dependent pathway; the resulting production of IL-1β and IL-8 through the NFκB pathway induces pro-inflammatory and/or chemotactic effects. Alternatively, serum amyloid A may stimulate neutrophils that induce the secretion of MMP9 from infected tissues, resulting in the cleavage and activation of IL-8. IL-8, in turn, would enhance neutrophil chemotaxis. Infection also induced expression of genes encoding C3, C6, C7, C8, and C9, which induce the complement system and form the membrane attack complex to lyse the bacteria membrane. The qPCR results indicated that TLR5 is significantly increased between 10 and 16 h, IL-1β between 8 and 16 h, IL-8 between 8 and 12 h, and C6 between 4 and 16 h, as compared to levels in the control. One antimicrobial peptide, hepcidin, was also strongly expressed between 4 and 10 h in infected fish. The results indicate that V. alginolyticus infection probably induces an immune response via TLR5-mediated regulation of down-stream cytokine gene expression. A second possibility is that the complement system and hepcidin may be involved in the immune response. These results may be applied by examining the immune effects of feeding E. lanceolatus larvae on a recombinant protein mixture based on the up-regulated genes.

Immunological hallmarks of stromal cells in the tumour microenvironment

A dynamic and mutualistic interaction between tumour cells and the surrounding stroma promotes the initiation, progression, metastasis and chemoresistance of solid tumours. Far less understood is the relationship between the stroma and tumour-infiltrating leukocytes; however, emerging evidence suggests that the stromal compartment can shape antitumour immunity and responsiveness to immunotherapy. Thus, there is growing interest in elucidating the immunomodulatory roles of the stroma that evolve within the tumour microenvironment. In this Review, we discuss the evidence that stromal determinants interact with leukocytes and influence antitumour immunity, with emphasis on the immunological attributes of stromal cells that may foster their protumorigenic function.

Shared epitope-antagonistic ligands: a new therapeutic strategy in mice with erosive arthritis

OBJECTIVE

The mechanisms underlying bone damage in rheumatoid arthritis (RA) are incompletely understood. We recently identified the shared epitope (SE), an HLA-DRB1-coded 5-amino acid sequence motif carried by the majority of RA patients as a signal transduction ligand that interacts with cell surface calreticulin and accelerates osteoclast (OC)-mediated bone damage in collagen-induced arthritis (CIA). Given the role of the SE/calreticulin pathway in arthritis-associated bone damage, we sought to determine the therapeutic targetability of calreticulin.

METHODS

A library of backbone-cyclized peptidomimetic compounds, all carrying an identical core DKCLA sequence, was synthesized. The ability of these compounds to inhibit SE-activated signaling and OC differentiation was tested in vitro. The effect on disease severity and OC-mediated bone damage was studied by weekly intraperitoneal administration of the compounds to DBA/1 mice with CIA.

RESULTS

Two members of the peptidomimetics library were found to have SE-antagonistic effects and antiosteoclast differentiation effects at picomolar concentrations in vitro. The lead mimetic compound, designated HS(4-4)c Trp, potently ameliorated arthritis and bone damage in vivo when administered in picogram doses to mice with CIA. Another mimetic analog, designated HS(3-4)c Trp, was found to lack activity, both in vitro and in vivo. The differential activity of the 2 analogs depended on minor differences in their respective ring sizes and correlated with distinctive geometry when computationally docked to the SE binding site on calreticulin.

CONCLUSION

These findings identify calreticulin as a novel therapeutic target in erosive arthritis and provide sound rationale and early structure/activity relationships for future drug design.

Thrombospondin-1 as a Regulator of Corneal Inflammation and Lymphangiogenesis: Effects on Dry Eye Disease and Corneal Graft Immunology

Thrombospondin-1 (TSP-1) is a matricellular glycoprotein that belongs to a family of evolutionary highly conserved calcium-binding proteins consisting of 5 members (TSP-1-TSP-5). In the eye, TSP-1 is expressed by several ocular cell types and is also detectable in the aqueous humor and the vitreous body. So far, TSP-1 is one of the major activators of TGFβ, suggesting a strong influence on various important cellular functions and interactions such as differentiation, migration, and wound healing. TSP-1 is also a key endogenous inhibitor of hem- and lymphangiogenesis. Several lines of evidence indicate a crucial role of TSP-1 in maintaining the ocular immune and angiogenic privilege, for example, by regulating T lymphocytes and the tolerance-promoting properties of ocular antigen-presenting cells. This review discusses the role of TSP-1 in dry eye disease and corneal graft rejection through its effects on hem- and lymphangiogenesis, as well as on the underlying immune responses. Recent work will be reviewed showing by which molecular mechanism TSP-1 modulates inflammatory processes during ocular diseases. This opens potential new treatment avenues in inflammatory and (lymph)angiogenic ocular diseases.

Antigen-induced regulation of T-cell motility, interaction with antigen-presenting cells and activation through endogenous thrombospondin-1 and its receptors

Antigen recognition reduces T-cell motility, and induces prolonged contact with antigen-presenting cells and activation through mechanisms that remain unclear. Here we show that the T-cell receptor (TCR) and CD28 regulate T-cell motility, contact with antigen-presenting cells and activation through endogenous thrombospondin-1 (TSP-1) and its receptors low-density lipoprotein receptor-related protein 1 (LRP1), calreticulin and CD47. Antigen stimulation induced a prominent up-regulation of TSP-1 expression, and transiently increased and subsequently decreased LRP1 expression whereas calreticulin was unaffected. This antigen-induced TSP-1/LRP1 response down-regulated a motogenic mechanism directed by LRP1-mediated processing of TSP-1 in cis within the same plasma membrane while promoting contact with antigen-presenting cells and activation through cis interaction of the C-terminal domain of TSP-1 with CD47 in response to N-terminal TSP-1 triggering by calreticulin. The antigen-induced TSP-1/LRP1 response maintained a reduced but significant motility level in activated cells. Blocking CD28 co-stimulation abrogated LRP1 and TSP-1 expression and motility. TCR/CD3 ligation alone enhanced TSP-1 expression whereas CD28 ligation alone enhanced LRP1 expression. Silencing of TSP-1 inhibited T-cell conjugation to antigen-presenting cells and T helper type 1 (Th1) and Th2 cytokine responses. The Th1 response enhanced motility and increased TSP-1 expression through interleukin-2, whereas the Th2 response weakened motility and reduced LRP1 expression through interleukin-4. Ligation of the TCR and CD28 therefore elicits a TSP-1/LRP1 response that stimulates prolonged contact with antigen-presenting cells and, although down-regulating motility, maintains a significant motility level to allow serial contacts and activation. Th1 and Th2 cytokine responses differentially regulate T-cell expression of TSP-1 and LRP1 and motility.

Thrombospondin-1 induces differential response in human corneal and conjunctival epithelial cells lines under in vitro inflammatory and apoptotic conditions

Recently, thrombospondin-1 (TSP-1) has been reported to be critical for maintaining a healthy ocular surface. The purpose of the study was to characterize the expression of TSP-1 and of its receptors CD36 and CD47 in corneal and conjunctival epithelial cells and determine the effect of exogenous TSP-1 treatment on these cells, following the induction of inflammation- and apoptosis-related changes. The expression of TSP-1, CD36 and CD47 by corneal and conjunctival cell lines was firstly characterized by ELISA, immunofluorescence analysis, Western blotting and reverse transcription polymerase chain reaction (RT-PCR). Benzalkonium chloride (BAC) exposure for 5 or 15 min was used as pro-inflammatory and pro-apoptotic stimulus for corneal or conjunctival epithelial cells, respectively. To analyze inflammation and apoptosis-related changes, IL-6 and TGF-β2 secretion determined by ELISA was used as inflammatory markers, while activated caspase-3/7 levels and cell viability, determined by CellEvent™ Caspase-3/7 Green Detection Reagent and XTT cytotoxicity assay, respectively, were used as apoptotic markers. Changes in CD36 and CD47 mRNA expression were quantified by real time RT-PCR. Corneal epithelial cells secreted and expressed higher protein levels of TSP-1 than conjunctival epithelial cells, although TSP-1 mRNA expression levels were similar and had lower CD36 and CD47, both at protein and mRNA levels. Both cell lines responded to exogenous TSP-1 treatment increasing CD36 at protein and mRNA levels. Blocking experiments revealed a predominance of TSP-1/CD47 rather than TSP-1/CD36 interactions to up-regulate CD36 levels in conjunctival epithelial cells, but not in corneal epithelial cells. BAC exposure increased IL-6 secretion and caspase-3/7 levels and decreased cell viability in both, corneal and conjunctival epithelial cells. Moreover, BAC exposure increased latent TGF-β2 levels in conjunctival epithelial cells. Interestingly, CD36 mRNA expression was down-regulated after BAC exposure in both cell lines. Exogenous TSP-1 treatment reduced TGF-β2 up-regulated levels by BAC exposure in conjunctival epithelial cells and less pronounced reduced IL-6 in BAC-exposed corneal epithelial cells. The effect on CD36 and CD47 regulation was less pronounced or even opposite depending on the inflammation- and apoptosis-related markers tested. Our results show evidence of the capacity of corneal and conjunctival epithelial cells to respond to TSP-1 via CD36 or CD47. Experimental simulation of inflammation- and apoptosis-related conditions changed the effects differentially elicited by TSP-1 on corneal and conjunctival epithelial cells, suggesting an unexpected and relevant contribution of TSP-1 on ocular surface homeostasis regulation.

The story of CD4+ CD28- T cells revisited: solved or still ongoing?

CD4⁺CD28⁻ T cells are a unique type of proinflammatory T cells characterised by blockade of costimulatory CD28 receptor expression at the transcriptional level, which is still reversible by IL-12. In healthy individuals older than 65 years, these cells may accumulate to up to 50% of total CD4⁺ T lymphocytes as in many immune-mediated diseases, immunodeficiency, and specific infectious diseases. Here we focus on CD4⁺CD28⁻ T cells in chronic immune-mediated diseases, summarizing various phenotypic and functional characteristics, which vary depending on the underlying disease, disease activity, and concurrent treatment. CD4⁺CD28⁻ T cells present as effector/memory cells with increased replicative history and oligoclonality but reduced apoptosis. As an alternative costimulatory signal instead of CD28, not only natural killer cell receptors and Toll-like receptors, but also CD47, CTLA-4, OX40, and 4-1BB have to be considered. The proinflammatory and cytotoxic capacities of these cells indicate an involvement in progression and maintenance of chronic immune-mediated disease. So far it has been shown that treatment with TNF-α blockers, abatacept, statins, and polyclonal antilymphocyte globulins (ATG) mediates reduction of the CD4⁺CD28⁻ T cell level. The clinical relevance of targeting CD4⁺CD28⁻ T cells as a therapeutic option has not been examined so far.

Thrombospondin-1 production is enhanced by Porphyromonas gingivalis lipopolysaccharide in THP-1 cells

Periodontitis is a chronic inflammatory disease caused by gram-negative anaerobic bacteria. Monocytes and macrophages stimulated by periodontopathic bacteria induce inflammatory mediators that cause tooth-supporting structure destruction and alveolar bone resorption. In this study, using a DNA microarray, we identified the enhanced gene expression of thrombospondin-1 (TSP-1) in human monocytic cells stimulated by Porphyromonas gingivalis lipopolysaccharide (LPS). TSP-1 is a multifunctional extracellular matrix protein that is upregulated during the inflammatory process. Recent studies have suggested that TSP-1 is associated with rheumatoid arthritis, diabetes mellitus, and osteoclastogenesis. TSP-1 is secreted from neutrophils, monocytes, and macrophages, which mediate immune responses at inflammatory regions. However, TSP-1 expression in periodontitis and the mechanisms underlying TSP-1 expression in human monocytic cells remain unknown. Here using real-time RT-PCR, we demonstrated that TSP-1 mRNA expression level was significantly upregulated in inflamed periodontitis gingival tissues and in P. gingivalis LPS-stimulated human monocytic cell line THP-1 cells. TSP-1 was expressed via Toll-like receptor (TLR) 2 and TLR4 pathways. In P. gingivalis LPS stimulation, TSP-1 expression was dependent upon TLR2 through the activation of NF-κB signaling. Furthermore, IL-17F synergistically enhanced P. gingivalis LPS-induced TSP-1 production. These results suggest that modulation of TSP-1 expression by P. gingivalis plays an important role in the progression and chronicity of periodontitis. It may also contribute a new target molecule for periodontal therapy.

Surface profiles of live colorectal cancer cells and tumor infiltrating lymphocytes from surgical samples correspond to prognostic categories

Extensive surface profiles of colorectal cancer (CRC) cells and tumor infiltrating lymphocytes (TIL) have been obtained from 45 surgical resection samples. Live cells were captured on an antibody microarray and stained with fluorescently-labeled antibodies. Minimal panels of 11 CRC antigens (CD13, CD24, CD26, CD49d, CD138, CD166, CA-125, CA19-9, EGFR, Galectin-4 and HLA-DR) and 11 T-cell antigens (CD10, CD11b, CD11c, CD25, CD31, CD95, CD151, CD181, Galectin-4, CA19-9, TSP-1) provide signatures for relapse and survival. Hierarchical clustering of profiles from CRC cells and TIL identified groups of patients for survival, systemic relapse and death. The groups from CRC and TIL profiles for systemic relapse showed 79.2% concordance, enabling prediction of relapse after surgery. The results demonstrate communication between CRC cells and TIL.

CD47 signaling regulates the immunosuppressive activity of VEGF in T cells

Thrombospondin-1 (TSP1) inhibits angiogenesis, in part, by interacting with the ubiquitous cell-surface receptor CD47. In endothelial cells, CD47 interacts directly with vascular endothelial growth factor receptor (VEGFR)-2, and TSP1 inhibits VEGFR2 phosphorylation and signaling by disrupting this association. We show that CD47 similarly associates with and regulates VEGFR2 in T cells. TSP1 inhibits phosphorylation of VEGFR2 and its downstream target Src in wild type but not in CD47-deficient human Jurkat and primary murine T cells. VEGFR2 signaling inhibits proliferation and TCR signaling in wild type T cells. However, ligation of CD47 by TSP1 or loss of CD47 expression reverses some inhibitory effects of VEGF on proliferation and T cell activation. We further found that VEGF and VEGFR2 expression are upregulated in CD47-deficient murine CD4(+) and human Jurkat T cells, and the resulting autocrine VEGFR2 signaling enhances proliferation and some TCR responses in the absence of CD47. Thus, CD47 signaling modulates the ability of VEGF to regulate proliferation and TCR signaling, and autocrine production of VEGF by T cells contributes to this regulation. This provides a mechanism to understand the context-dependent effects of TSP1 and VEGF on T cell activation, and reveals an important role for CD47 signaling in regulating T cell production of the major angiogenic factor VEGF.

Invoking the power of thrombospondins: regulation of thrombospondins expression

Increasing evidence suggests critical functions of thrombospondins (TSPs) in a variety of physiological and pathological processes. With the growing understanding of the importance of these matricellular proteins, the need to understand the mechanisms of regulation of their expression and potential approaches to modulate their levels is also increasing. The regulation of TSP expression is multi-leveled, cell- and tissue-specific, and very precise. However, the knowledge of mechanisms modulating the levels of TSPs is fragmented and incomplete. This review discusses the known mechanisms of regulation of TSP levels and the gaps in our knowledge that prevent us from developing strategies to modulate the expression of these physiologically important proteins.

[Role of thrombospondin-1 in the development of kidney diseases]

Thrombospondin-1 (TSP-1) is a 450-kDa matricellar glycoprotein. By its various domains, it can interact with various partners and exhibit anti-angiogenic, pro-apoptotic and immunomodulatory activities. TSP-1 is also a major endogenous activator of the pro-fibrotic growth factor TGF-β. In healthy adult renal parenchyma, TSP-1 expression is very scarce and limited to Bowman's capsule and interstitium. During nephropathies, many cell types can express or secrete TSP-1 (mesangial, endothelial, smooth muscle, tubular cells, podocytes and fibroblasts) depending on the nature of injury and the evolutive stage of the disease. Inhibition of the different domains of TSP-1 using specific antibodies or peptides, blockade of TSP-1 expression by antisense oligonucleotides and use of knock-out mice, allowed to identify the role of TSP-1 in various models of experimental nephropathy. All these studies demonstrated a deleterious effect of TSP-1 on renal repair by inducing TGF-β and fibrosis, decreasing VEGF and capillary density, and enhancing inflammatory cells recruitment. Thus, TSP-1 represents a potential therapeutic target for the management of chronic kidney diseases.

Thrombospondins: old players, new games

PURPOSE OF REVIEW

Thrombospondins (TSPs) are secreted extracellular matrix (ECM) proteins from TSP family, which consists of five homologous members. They share a complex domain structure and have numerous binding partners in ECM and multiple cell surface receptors. Information that has emerged over the past decade identifies TSPs as important mediators of cellular homeostasis, assigning new important roles in cardiovascular pathology to these proteins.

RECENT FINDINGS

Recent studies of the functions of TSP in the cardiovascular system, diabetes and aging, which placed several TSPs in a position of critical regulators, demonstrated the involvement of these proteins in practically every aspect of cardiovascular pathophysiology related to atherosclerosis: inflammation, immunity, leukocyte recruitment and function, function of vascular cells, angiogenesis, and responses to hypoxia, ischemia and hyperglycemia. TSPs are also critically important in the development and ultimate outcome of the complications associated with atherosclerosis--myocardial infarction, and heart hypertrophy and failure. Their expression and significance increase with age and with the progression of diabetes, two major contributors to the development of atherosclerosis and its complications.

SUMMARY

This overview of recent literature examines the latest information on the newfound functions of TSPs that emphasize the importance of ECM in cardiovascular homeostasis and pathology. The functions of TSPs in myocardium, vasculature, vascular complications of diabetes, aging and immunity are discussed.

Thrombospondin-1 regulates adiposity and metabolic dysfunction in diet-induced obesity enhancing adipose inflammation and stimulating adipocyte proliferation

As a typical matricellular protein, thrombospondin (TSP)-1, binds to the structural matrix and regulates cellular behavior by modulating growth factor and cytokine signaling. Obesity and diabetes are associated with marked upregulation of TSP-1 in adipose tissue. We hypothesized that endogenous TSP-1 may play an important role in the pathogenesis of diet-induced obesity and metabolic dysfunction. Accordingly, we examined the effects of TSP-1 gene disruption on weight gain, adiposity, and adipose tissue inflammation in mice receiving a high-fat diet (HFD: 60% fat, 20% carbohydrate) or a high-carbohydrate low-fat diet (HCLFD: 10% fat, 70% carbohydrate). HFD mice had significantly higher TSP-1 expression in perigonadal adipose tissue; TSP-1 was predominantly localized in the adipose interstitium. TSP-1 loss attenuated weight gain and fat accumulation in HFD and HCLFD groups. Compared with corresponding wild-type animals, TSP-1-null mice had decreased insulin levels but exhibited elevated free fatty acid and triglyceride levels, suggesting impaired fatty acid uptake. TSP-1 loss did not affect adipocyte size and had no effect on adipose vascular density. However, TSP-1-null mice exhibited attenuated tumor necrosis factor-α mRNA expression and reduced macrophage infiltration, suggesting a role for TSP-1 in mediating obesity-associated inflammation. In vitro, TSP-1 enhanced proliferation of 3T3-L1 preadipocytes but did not modulate inflammatory cytokine and chemokine synthesis. In conclusion, TSP-1 upregulation contributes to weight gain, adipose growth, and the pathogenesis of metabolic dysfunction. The effects of TSP-1 may involve stimulation of adipocyte proliferation, activation of inflammatory signaling, and facilitated fatty acid uptake by adipocytes.

Progression of lumbar spinal stenosis is influenced by polymorphism of thrombospondin 2 gene in the Korean population

PURPOSE

The aim of this study is to determine the contribution of thrombospondin 2 (THBS2) polymorphisms to the development and progression of lumbar spinal stenosis (LSS) in the Korean population.

METHODS

We studied 148 symptomatic patients with radiographically proven LSS and 157 volunteers with no history of back problems from our institution. Magnetic resonance images were obtained for all the patients and controls. Quantitative image evaluation for LSS was performed to evaluate the severity of LSS. All patients and controls were genotyped for THBS2 allele variations using a polymerase chain reaction-based technique.

RESULTS

We found no causal single nucleotide polymorphism (SNPs) in THBS2 that were significantly associated with LSS. Two SNPs (rs6422747, rs6422748) were over-represented in controls [P = 0.042, odds ratio [OR] = 0.55 and P = 0.042, OR = 0.55, respectively]. Haplotype analysis showed that the ''AGAGACG'' haplotype (HAP4) and ''AAGGACG'' haplotype (HAP5) were over-represented in severe LSS patients (P = 0.0147, OR = 2.02 and P = 0.0137, OR = 2.48, respectively). In addition, the ''AAAGGGG'' haplotype (HAP1) was over-represented in controls (P = 0.0068, OR = 0.30).

CONCLUSIONS

Although no SNPs in THBS2 were associated with LSS, haplotypes (HAP4 and HAP5) were significantly associated with progression of LSS in the Korean population, whereas another haplotype (HAP1) may play a protective role against LSS development.

Functional consequences of platelet binding to T lymphocytes in inflammation

Expression of the scavenger receptor CD36 on lymphocytes is intriguing. We observed that a minor subpopulation of lymphocytes expressed CD36 on the cell surface. We investigated the source of CD36 and also the proliferation and cytokine production of these CD36(+) CD4(+) lymphocytes. Flow cytometry analysis and immunofluorescence microscopy showed that CD36(+) platelets were responsible for CD36 detection on lymphocytes. CD36 was then used as a tool to characterize lymphocytes with bound platelets. Activation-induced proliferation was lower in CD4(+) lymphocytes with bound platelets than lymphocytes without bound platelets. IL-17 and IFN-γ production was also reduced in lymphocytes with bound platelets. We then studied the presence of CD36(+) CD4(+) lymphocytes in RA patients. We observed that the percentage of CD4(+) lymphocytes with bound platelets was higher on RA patients than in healthy donors. RA patients with higher titers of anti-CCP, RF levels, and cardiovascular risk index presented a lower percentage of CD4(+) lymphocytes with bound platelets. These patients also had higher IL-17 and IFN-γ production. These results suggest that platelet-binding modifies lymphocyte function. This binding could be a regulatory mechanism in RA that confers a less severe phenotype.

Matricellular proteins in cardiac adaptation and disease

The term matricellular proteins describes a family of structurally unrelated extracellular macromolecules that, unlike structural matrix proteins, do not play a primary role in tissue architecture, but are induced following injury and modulate cell-cell and cell-matrix interactions. When released to the matrix, matricellular proteins associate with growth factors, cytokines, and other bioactive effectors and bind to cell surface receptors transducing signaling cascades. Matricellular proteins are upregulated in the injured and remodeling heart and play an important role in regulation of inflammatory, reparative, fibrotic and angiogenic pathways. Thrombospondin (TSP)-1, -2, and -4 as well as tenascin-C and -X secreted protein acidic and rich in cysteine (SPARC), osteopontin, periostin, and members of the CCN family (including CCN1 and CCN2/connective tissue growth factor) are involved in a variety of cardiac pathophysiological conditions, including myocardial infarction, cardiac hypertrophy and fibrosis, aging-associated myocardial remodeling, myocarditis, diabetic cardiomyopathy, and valvular disease. This review discusses the properties and characteristics of the matricellular proteins and presents our current knowledge on their role in cardiac adaptation and disease. Understanding the role of matricellular proteins in myocardial pathophysiology and identification of the functional domains responsible for their actions may lead to design of peptides with therapeutic potential for patients with heart disease.

The expression of sonic hedgehog in diabetic wounds following treatment with poly(methacrylic acid-co-methyl methacrylate) beads

The expression of native sonic hedgehog (Shh) was significantly increased in poly(methacrylic acid-co-methyl methacrylate) bead (MAA) treated wounds at day 4 compared to both poly(methyl methacrylate) bead (PMMA) treated and untreated wounds in diabetic db/db mice. MAA beads also increased the expression of the Shh transcription factor Gli3 at day 4. Previously, topical application of MAA beads (45 mol % methacrylic acid) improved wound closure and blood vessel density in excisional wounds in these mice, while PMMA beads did not. Gene expression within the granulation tissue of healing wounds was studied to provide insight into the mechanism of vessel formation and wound healing in the presence of MAA beads. In addition to the increased expression of Shh, MAA-treated wounds had increased expression of osteopontin (OPN), IL-1β and TNF-α, (at day 7) similar to the previously reported MAA response of macrophage-like and endothelial cells in vitro.

Matricellular proteins: a sticky affair with cancers

The multistep process of metastasis is a major hallmark of cancer progression involving the cointeraction and coevolution of the tumor and its microenvironment. In the tumor microenvironment, tumor cells and the surrounding stromal cells aberrantly secrete matricellular proteins, which are a family of nonstructural proteins in the extracellular matrix (ECM) that exert regulatory roles via a variety of molecular mechanisms. Matricellular proteins provide signals that support tumorigenic activities characteristic of the metastastic cascade such as epithelial-to-mesenchymal (EMT) transition, angiogenesis, tumor cell motility, proliferation, invasion, evasion from immune surveillance, and survival of anoikis. Herein, we review the current understanding of the following matricellular proteins and highlight their pivotal and multifacted roles in metastatic progression: angiopoietin-like protein 4 (ANGPTL4), CCN family members cysteine-rich angiogenic inducer 61 (Cyr61/CCN1) and CCN6, osteopontin (OPN), secreted protein acidic and rich in cysteine (SPARC), tenascin C (TNC), and thrombospondin-1 and -2 (TSP1, TSP2). Insights into the signaling mechanisms resulting from the interaction of these matricellular proteins and their respective molecular partner(s), as well as their subsequent contribution to tumor metastasis, are discussed. In addition, emerging evidences of their promising potential as therapeutic options and/or targets in the treatment of cancer are also highlighted.

The role of thrombospondin 1 on intestinal inflammation and carcinogenesis

Crohn’s disease and ulcerative colitis are inflammatory bowel diseases (IBD) quite common in the United States and other Western countries. Patients suffering IBD are at greater risk of developing colorectal adenocarcinoma than the general population. Both, the adenomacarcinoma and the inflammation-carcinogenesis processes are characterized by active angiogenesis. Recent studies also have shown that anti-angiogenesis might be a novel therapeutic approach for IBD. Thrombospondin 1 (TSP1) is an extracellular protein well known for its anti-angiogenic properties. TSP1 also has key functions in inflammation, which is assumed to be the primary cause for carcinogenesis in IBD. This review is focused on the role of TSP1 in colorectal carcinogenesis. The therapeutic effects of TSP derived-peptides on inhibiting the inflammation-carcinogenesis progression are also discussed.

Interactions between the extracellular matrix and inflammation during viral myocarditis

Viral myocarditis is a life-threatening disease characterized by severe cardiac inflammation that can result in heart failure or sudden cardiac death in previously healthy adults. In a subset of patients, it may result in the development of dilated cardiomyopathy due to the chronic inflammatory process. Despite its clinical need, specific treatments for myocarditis are currently not available. The extracellular matrix (ECM) under normal conditions, functions to maintain the mechanical and structural integrity of the heart but can adapt under pathological circumstances to preserve cardiac function. Recent studies have revealed a crucial role of the ECM in the reparative process after cardiac insult, not only as a key component in cardiac remodeling but also as a regulator of the inflammatory process. Increasing our understanding of the impact the ECM has in the disease pathogenesis and progression of viral myocarditis, might lead to much needed therapeutic interventions. In this review we will describe the pathology of viral myocarditis and illustrate the interplay between inflammation and the ECM in general terms, and during viral myocarditis.

Gene selection in arthritis classification with large-scale microarray expression profiles

The use of large-scale microarray expression profiling to identify predictors of disease class has become of major interest. Beyond their impact in the clinical setting (i.e. improving diagnosis and treatment), these markers are also likely to provide clues on the molecular mechanisms underlining the diseases. In this paper we describe a new method for the identification of multiple gene predictors of disease class. The method is applied to the classification of two forms of arthritis that have a similar clinical endpoint but different underlying molecular mechanisms: rheumatoid arthritis (RA) and osteoarthritis (OA). We aim at both the classification of samples and the location of genes characterizing the different classes. We achieve both goals simultaneously by combining a binary probit model for classification with Bayesian variable selection methods to identify important genes.We find very small sets of genes that lead to good classification results. Some of the selected genes are clearly correlated with known aspects of the biology of arthritis and, in some cases, reflect already known differences between RA and OA.

Thrombospondin-1: multiple paths to inflammation

Inflammation is a defensive process against tissue injury. Once this self-protective strategy is initiated, an effective resolution of the process is crucial to avoid major and unnecessary tissue damage. If the underlying event inducing inflammation is not addressed and homeostasis is not restored, this process can become chronic and lead to angiogenesis and carcinogenesis. Thrombospondin-1 (TSP-1) is a matricellular protein involved in angiogenesis, cancer, and inflammation. The effects of TSP-1 have been studied in many preclinical tumor models, and mimetic peptides are being tested in cancer clinical trials. However, the molecular mechanisms explaining its role in inflammatory processes are not well understood. This paper will discuss the role of TSP-1 in inflammation and its interaction with key receptors that may explain its functions in that process. Recent literature will be reviewed showing novel mechanisms by which this multifaceted protein could modulate the inflammatory process and impact its resolution.

Transcriptional Profiling of Liver and Effect of Glucocorticoids in a Rat Adjuvant-Induced Arthritis Model

Glucocorticoids (GCs), despite having many undesirable side effects, remain effective for the treatment of many inflammatory diseases and are commonly used as benchmark drugs in animal models of disease. However, the molecular mechanisms underling systemic GC effects in these models are poorly characterized. In this study, prednisolone and dexamethasone were evaluated in the fully established Lewis rat adjuvant-induced arthritis (AIA) model. In AIA, adjuvant administration induced polyarticular and systemic inflammation, which included spleen and liver. In the liver, multifocal hepatic granulomas were observed. To characterize the systemic response and the pathways responsible for GC effects, histology, transcriptional profiling, and immunohistochemistry (IHC) were performed. There was a decrease in the incidence and histologic severity score for granulomas with GC treatment. There was no effect on cellular composition of granulomas as assessed by IHC for CD3+ lymphocytes, macrophages, and B cells, but there was a significant reduction in infiltrating lymphocytes in the hepatic parenchyma. By Affymetrix microarray analysis, 10% of hepatic transcripts were altered ( P < .01) in livers from AIA rats, with ~31% of them partially reversed with treatment with dexamethasone and ~13% with prednisolone. Many of these altered hepatic transcripts correspond to human genes that are dysregulated in the synovium in human rheumatoid arthritis (RA), indicating that the rat AIA model shares features with human RA. These data establish molecular changes in the liver and the effect of GCs in rat AIA, which can be used to aid in understanding the mechanism of action of novel anti-inflammatory compounds in this animal model.

Changes in the porcine peripheral blood mononuclear cell proteome induced by infection with highly virulent classical swine fever virus

Leukopenia and immunosuppression are characteristic clinical manifestations of classical swine fever and peripheral blood mononuclear cells (PBMCs) are major targets of classical swine fever virus. To investigate proteomic expression changes in swine PBMCs during lethal CSFV infection, proteins of PBMCs from five lethally CSFV-infected pigs were resolved by two-dimensional electrophoresis followed by mass spectrometry. Quantitative intensity analysis revealed that 66 protein spots showed altered expression, 44 of which were identified as 34 unique proteins by MALDI-TOF-MS/MS. Cellular functions of these proteins included cytoskeletal, energy metabolism, protein translation and processing, antioxidative stress, heat shock and blood clotting. Western blot analysis confirmed the upregulation of annexin A1 and downregulation of cofilin. Identification of these changed levels of expression provides an understanding at the molecular level of the response of in vivo target cells to CSFV infection and of the pathogenic mechanisms of leukopenia and immunosuppression induced by the virus.

Aberrant methylation of thrombospondin-1 and its association with reduced expression in gastric cardia adenocarcinoma

AIM

Investigate the promoter methylation of the Thrombospondin-1 (TSP1) gene in gastric cardia adenocarcinoma (GCA).

METHODS

MSP approach, immunohistochemistry method, and RT-PCR were used respectively to examine the promoter methylation of TSP1, its protein and mRNA expression in tumors and corresponding normal tissues. The expression and concentration of TGF-beta1 were examined respectively by immunohistochemistry and ELISA method. The status of T cell immunity was examined by Flow cytometry analysis.

RESULTS

TSP1 was methylated in 34/96 (35.4%) tumor specimens, which was significantly higher than that in corresponding normal tissues (P < .001). Protein and mRNA expression of TSP1 in GCA tumor tissues were reduced significantly and were associated with TSP1 methylation. The protein expression of TGF-beta1 was significantly higher in tumor tissues (P < .001) and was associated with TNM stage and histological differentiation. The concentration of active and total TGF-beta1 did not show significant difference between the GCA patients with hypermethylation of TSP1 and without methylation of TSP1 (P > .05). The function of T cell immunity was significantly different between the GCA patients with hypermethylation of TSP1 and without methylation of TSP1.

CONCLUSIONS

Epigenetic silencing of TSP1 gene by promoter hypermethylation may play an important role in GCA.