Roles of CD147 on T lymphocytes activation and MMP-9 secretion in systemic lupus erythematosus

Pathogenic T Cells in Celiac Disease Change Phenotype on Gluten Challenge: Implications for T-Cell-Directed Therapies

Gluten-specific CD4+ T cells being drivers of celiac disease (CeD) are obvious targets for immunotherapy. Little is known about how cell markers harnessed for T-cell-directed therapy can change with time and upon activation in CeD and other autoimmune conditions. In-depth characterization of gluten-specific CD4+ T cells and CeD-associated (CD38+ and CD103+ ) CD8+ and γδ+ T cells in blood of treated CeD patients undergoing a 3 day gluten challenge is reported. The phenotypic profile of gluten-specific cells changes profoundly with gluten exposure and the cells adopt the profile of gluten-specific cells in untreated disease (CD147+ , CD70+ , programmed cell death protein 1 (PD-1)+ , inducible T-cell costimulator (ICOS)+ , CD28+ , CD95+ , CD38+ , and CD161+ ), yet with some markers being unique for day 6 cells (C-X-C chemokine receptor type 6 (CXCR6), CD132, and CD147) and with integrin α4β7, C-C motif chemokine receptor 9 (CCR9), and CXCR3 being expressed stably at baseline and day 6. Among gluten-specific CD4+ T cells, 52% are CXCR5+ at baseline, perhaps indicative of germinal-center reactions, while on day 6 all are CXCR5- . Strikingly, the phenotypic profile of gluten-specific CD4+ T cells on day 6 largely overlaps with that of CeD-associated (CD38+ and CD103+ ) CD8+ and γδ+ T cells. The antigen-induced shift in phenotype of CD4+ T cells being shared with other disease-associated T cells is relevant for development of T-cell-directed therapies.

Azithromycin: The First Broad-spectrum Therapeutic

The Strategic Plan for Biodefense Research by the U.S. Department of Health and Human Services demarcates the need for drugs which target multiple types of pathogens to prepare for infectious threats. Azithromycin is one such broad-spectrum therapeutic that is both included in the University of Oxford's RECOVERY and excluded from the World Health Organization's SOLIDARITY trials. Here we review azithromycin's broad antibiotic, antimalarial, antiviral pharmacology and contextualise it against a broader history as the most repositioned therapeutic of the macrolide class; we further evaluate azithromycin's clinical and socio-economic propriety for respiratory pandemics and delineate a model for its combinatorial mechanism of action against COVID-19 pneumonia.

CD147 Expressed on Memory CD4+ T Cells Limits Th17 Responses in Patients With Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease in which T helper-type 17 (Th17) cells have been critically involved. CD147 is a T cell activation-associated molecule and is involved in T cell development. However, it remains unclear whether CD147 participates in Th17 responses in RA patients. In this study, we demonstrated that in both the RA and healthy controls (HC) groups, CD147 expression on CD4⁺ T cells was increased in CCR6⁺ and CD161⁺ subsets, and was associated with IL-17 production. Ligation of CD147 with its monoclonal antibody (mAb) strongly inhibited Th17 responses, and knock down of CD147 expression on CD4⁺ Tm cells specifically enhanced Th17 responses, triggered by coculture with in vitro activated monocytes from HC. Further functional studies showed that anti-CD147 mAb decreased the activation of AKT, mTORC1 and STAT3 signaling, which is known to enhance Th17 responses. Ligation of CD147 with its mAb on CD4⁺ Tm cells specifically reduced Th17 responses induced by in vitro or in vivo activated monocytes from RA patients. In collagen-induced arthritis model, anti-CD147 mAb treatment reduced the Th17 levels and severity of arthritis in vivo. These data suggest that CD147 plays a negative role in regulating human Th17 responses. Anti-CD147 mAb can limit the extraordinary proliferation of Th17 cells and may be a new therapeutic option in RA.

Autoimmunity as the comet tail of COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can give rise to different clinical manifestations that are directly related to viral tissue damage or indirectly induced by the antiviral immune response. Hyper-activation of the immune system in an attempt to eradicate the infection may trigger autoimmunity. Several immune-mediated disorders have been described in SARS-CoV-2-infected individuals. These include cutaneous rashes and vasculitis, autoimmune cytopenia, anti-phospholipid syndrome, central or peripheral neuropathy, myositis and myocarditis. On the other hand, rheumatic patients were reported to have similar coronavirus disease 2019 (COVID-19) incidence, morbidity and mortality rates compared to general population. This opinion review will summarize the crucial immunologic steps which occur during SARS-CoV-2-infection that may link autoimmunity to COVID-19 and provides an opportunity for further discussion regarding this association.

Azithromycin: The First Broad-spectrum Therapeutic

The Strategic Plan for Biodefense Research by the U.S. Department of Health and Human Services demarcates the need for drugs which target multiple types of pathogens to prepare for infectious threats. Azithromycin is one such broad-spectrum therapeutic that is both included in the University of Oxford's RECOVERY and excluded from the World Health Organization's SOLIDARITY trials. Here we review azithromycin's broad antibiotic, antimalarial, antiviral pharmacology and contextualise it against a broader history as the most disease-repositioned therapeutic of the macrolide class; we further evaluate azithromycin's clinical and socio-economic propriety for respiratory pandemics and delineate a model for its combinatorial mechanism of action against COVID-19 pneumonia.

Study of Serum CD147 Level in Patients with Transient Ischemic Attack and CD147 Expression in Atherosclerotic Plaque

There is growing evidence that highlighted the potential effects of CD147 in atherosclerosis, but the potential implication of CD147 in diagnosis and treatment of transient ischemic attack (TIA) and acute cerebral infarction (ACI) is still unclear. In this work, we investigated the serum level of CD147 in patients with TIA and ACI, and CD147 expression in atherosclerotic plaque. The result showed significantly increasing serum level of CD147 in patients with TIA and ACI, and increasing amount of CD147 in vulnerable plaque compared with that in migrating plaque. The serum level of CD147 was correlation with risk of stroke after an episode of TIA. These results together suggest a potential involvement of CD147 in the development and progression of TIA and ACI and CD147 as a potential biomarker for stroke prediction.

The combination of FK506 and an anti-CD147 mAb exerts potential therapeutic effects on a mouse model of collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and excessive T lymphocyte activation plays a critical role in the development of inflammation. CD147 is an antigen related to T cell activation, CD147 blockade exerts beneficial effects on RA. FK506, also known as tacrolimus, exerts strong immunosuppressive effects by inhibiting T cell activation. In this study, RL73 (an anti-mouse CD147 functional-grade purified antibody) and FK506 were co-administered to mice with collagen-induced arthritis (CIA). As expected, the combination of these two drugs produced superior therapeutic effects than either drug alone and enabled the administration of each drug at a lower dose. Moreover, joint damage and destruction were significantly improved in mice injected with both FK506 and RL73 compared with mice injected with either agent alone. These effects might have been observed because the proportions of CD4 + T and CD8 + T cells in the mouse spleen of the combination regimen were clearly decreased compared with each monotherapy. In addition, the proportions of Th2 subsets in the mouse spleen and peripheral blood were clearly increased, and the serum levels of the cytokines interleukin 4 (IL-4) and IL-10 were markedly increased in mice treated with the combination therapy compared with the other groups of mice. The splenic total number of T lymphocytes also showed that the inhibition of T lymphocytes was the most obvious in the combined treatment group. Based on the results from the present study, combining FK506 and the anti-CD147 mAb might be a new practical therapeutic option for the treatment of RA.

A critical epitope in CD147 facilitates memory CD4+ T-cell hyper-activation in rheumatoid arthritis

The abnormal activation of CD4⁺CD45RO⁺ memory T (Tm) cells plays an important role in the pathogenesis of rheumatoid arthritis (RA). Previous studies have shown that CD147 participates in T-cell activation. However, it remains unclear whether CD147 is involved in abnormal Tm-cell activation in RA patients. In this study, we demonstrated that CD147 was predominantly upregulated in Tm cells derived from RA patients. The anti-CD147 mAb 5A12 specifically inhibited Tm-cell activation and proliferation and further restrained osteoclastogenesis. Using a structural-functional approach, we depicted the interface between 5A12 and CD147. This allowed us to identify two critical residues, Lys63 and Asp65, as potential targets for RA treatment, as the double mutation K63A/D65A inhibited Tm-cell activation, mimicking the neutralization by 5A12. This study provides not only a theoretical basis for a "CD147-Tm/Osteoclast-RA chain" for the potential prevention and treatment of RA or other T-cell-mediated autoimmune diseases but also a new target for related drug design and development.

CD147/basigin limits lupus nephritis and Th17 cell differentiation in mice by inhibiting the interleukin-6/STAT-3 pathway

OBJECTIVE

Interleukin-17 (IL-17)-producing T cells (Th17 cells) play critical roles in the pathogenesis of immune-related diseases, including systemic lupus erythematosus. However, the fundamental mechanism regulating Th17 cell differentiation is not fully understood. Recently, we demonstrated that plasma levels of CD147/basigin (Bsg) in patients with lupus nephritis (LN) were closely associated with disease activity. but the molecular mechanism involving Bsg has been elusive. Here, we addressed the role of Bsg in the pathogenesis of LN.

METHODS

Injections of pristane (2,6,10,14-tetramethylpentadecane [TMPD]) were administered to Bsg(-/-) or Bsg(+/+) mice to induce LN. The mice were killed 6 months after being injected, for histologic and biochemical analyses of the kidneys and spleens.

RESULTS

Pristane induced LN more strikingly in Bsg(-/-) mice than in Bsg(+/+) mice, even though humoral autoimmunity was similarly increased in both genotypes. The increased number of Th17, but not Th1, Treg cells, was augmented in Bsg(-/-) mice. The expression of IL-17 was also increased in the kidneys of Bsg(-/-) mice, in proportion to LN disease activity. Furthermore, treatment with anti-IL-17 antibody reduced LN disease activity in Bsg(-/-) mice. Complementary to these phenotypes of Bsg(-/-) mice, Bsg expression was enhanced in activated CD4+ T cells in vivo and in vitro. Bsg deficiency selectively augmented in vitro differentiation of naive CD4+ T cells to Th17 cells and STAT-3 phosphorylation during this differentiation. Moreover, STAT-3 phosphorylation was suppressed by crosslinking of Bsg with its antibody.

CONCLUSION

Bsg plays an indispensable role in Th17 cell differentiation as a negative regulator by suppressing the IL-6/STAT-3 pathway.

Association Study between an SNP in CD147 and Its Expression With Acute Coronary Syndrome in a Jiangsu Chinese Population

CD147 is an important molecule in the inflammation and proteolysis process. This molecule crucially contributes to the initial and progression of atherosclerotic lesions. A single nucleotide polymorphism in CD147 gene, the rs8259 T/A in the 3'-untranslated region, is responsible for its expression in various cells. This study assessed whether the genetic variation rs8259 is associated with acute coronary syndrome (ACS) and CD147. A total of 943 ACS subjects and 439 stable angina subjects, and 851 controls were genotyped for rs8259 polymorphism by polymerase chain reaction restriction fragment length polymorphism and DNA-sequencing method. Plasma soluble CD147 (sCD147) level was measured by enzyme-linked immunosorbent assay. CD147 mRNA and protein expression in peripheral blood mononuclear cells were tested by real-time quantitative polymerase chain reaction and western blot, respectively. We found that TT genotype and T-allele frequency of CD147 rs8259 in ACS patients were much lower than the other patient groups. Significant difference was not observed between stable angina and controls. CD147 T allele was negatively related to ACS. ACS patients exhibited the highest CD147 expression in peripheral blood mononuclear cells and plasma sCD147 level. The plasma sCD147 levels in the culprit vessel were higher than those in the radial artery. In ACS patients, AA gene carriers had the highest CD147 levels, whereas TT gene carriers had the lowest CD147 levels. Linear regression analysis showed that genotypes and disease conditions contributed 49% to the change of the plasma CD147 level. These results suggested that the single nucleotide polymorphism of CD147 gene rs8259 T/A was associated with ACS susceptibility. Allele T gene may decrease the relative risk of suffering from ACS through downregulation of CD147 expression.

Zearalenone mycotoxin affects immune mediators, MAPK signalling molecules, nuclear receptors and genome-wide gene expression in pig spleen

The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level.

The role of EMMPRIN in T cell biology and immunological diseases

Review on EMMPRIN in numerous immunological/inflammatory disease conditions and its complex roles in T cell biology.

EMMPRIN (CD147), originally described as an inducer of the expression of MMPs, has gained attention in its involvement in various immunologic diseases, such that anti‐EMMPRIN antibodies are considered as potential therapeutic medications. Given that MMPs are involved in the pathogenesis of various disease states, it is relevant that targeting an upstream inducer would make for an effective therapeutic strategy. Additionally, EMMPRIN is now appreciated to have multiple roles apart from MMP induction, including in cellular functions, such as migration, adhesion, invasion, energy metabolism, as well as T cell activation and proliferation. Here, we review what is known about EMMPRIN in numerous immunologic/inflammatory disease conditions with a particular focus on its complex roles in T cell biology.

Function of CD147 in atherosclerosis and atherothrombosis

CD147, a member of the immunoglobulin super family, is a well-known potent inducer of extracellular matrix metalloproteinases. Studies show that CD147 is upregulated in inflammatory diseases. Atherosclerosis is a chronic inflammatory disease of the artery wall. Further understanding of the functions of CD147 in atherosclerosis and atherothrombosis may provide a new strategy for preventing and treating cardiovascular disease. In this review, we discuss how CD147 contributes to atherosclerosis and atherothrombosis.

The biological function and clinical utilization of CD147 in human diseases: a review of the current scientific literature

CD147 or EMMPRIN is a member of the immunoglobulin superfamily in humans. It is widely expressed in human tumors and plays a central role in the progression of many cancers by stimulating the secretion of matrix metalloproteinases (MMPs) and cytokines. CD147 regulates cell proliferation, apoptosis, and tumor cell migration, metastasis and differentiation, especially under hypoxic conditions. CD147 is also important to many organ systems. This review will provide a detailed overview of the discovery, characterization, molecular structure, diverse biological functions and regulatory mechanisms of CD147 in human physiological and pathological processes. In particular, recent studies have demonstrated the potential application of CD147 not only as a phenotypic marker of activated regulatory T cells but also as a potential diagnostic marker for early-stage disease. Moreover, CD147 is recognized as an effective therapeutic target for hepatocellular carcinoma (HCC) and other cancers, and exciting clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies.

Transcriptional profiling of melanoma sentinel nodes identify patients with poor outcome and reveal an association of CD30(+) T lymphocytes with progression

Sentinel lymph nodes set the stance of the immune system to a localized tumor and are often the first site to be colonized by neoplastic cells that metastasize. To investigate how the presence of neoplastic cells in sentinel lymph nodes may trigger pathways associated with metastatic progression, we analyzed the transcriptional profiles of archival sentinel node biopsy specimens obtained from melanoma patients. Biopsies from positive nodes were selected for comparable tumor infiltration, presence or absence of further regional node metastases, and relapse at 5-year follow-up. Unsupervised analysis of gene expression profiles revealed immune response to be a major gene ontogeny represented. Among genes upregulated in patients with progressing disease, the TNF receptor family member CD30/TNFRSF8 was confirmed in biopsy specimens from an independent group of patients. Immunohistochemical analysis revealed higher numbers of CD30(+) lymphocytes in nodes from progressing patients compared with nonprogressing patients. Phenotypic profiling demonstrated that CD30(+) lymphocytes comprised a broad population of suppressive or exhausted immune cells, such as CD4(+)Foxp3(+) or PD1(+) subpopulations and CD4(-)CD8(-) T cells. CD30(+) T lymphocytes were increased in peripheral blood lymphocytes of melanoma patients at advanced disease stages. Our findings reinforce the concept that sentinel nodes act as pivotal sites for determining progression patterns, revealing that the presence of CD30(+) lymphocytes at those sites associate positively with melanoma progression.

Plasma CD147 reflects histological features in patients with lupus nephritis

OBJECTIVE

A glycosylated transmembrane protein, CD147, has been implicated in regulating lymphocyte responsiveness and leukocyte recruitment. As lupus nephritis (LN) often follows a relapsing-remitting disease course, accurate understanding of the disease activity would be extremely helpful in improving prognosis. Unfortunately, neither clinical nor serological data can accurately reflect the histological features of LN. The present study investigated whether CD147 can accurately predict pathological features of LN.

METHODS

Plasma and spot urine samples were collected from 64 patients who underwent renal biopsy between 2008 and 2011. Disease activity for LN tissues was evaluated using the biopsy activity index, and compared to levels of biomarkers including CD147.

RESULTS

In LN tissues, CD147 induction was striking in injured glomeruli and infiltrating inflammatory cells, but not in damaged tubules representing atrophy. Plasma CD147 levels accurately reflected the histological disease activity. However, prediction using a single molecule would be quite difficult because of the complex pathogenesis of LN. The diagnostic accuracy of multiplex parameters indicated that the combination including plasma CD147 might yield excellent diagnostic abilities for guiding ideal LN therapy.

CONCLUSION

Plasma CD147 levels might offer useful insights into disease activity as a crucial biomarker in patients with LN.

Abnormalities in soluble CD147 / MMPs / TIMPs axis in Ankylosing Spondylitis patients with and without a history of Acute Anterior Uveitis / Anomalii ale axei CD147 solubil / MMPs / TIMPs la pacienții cu spondilită anchilozantă cu sau fără uveită acută anterioară

Ankylosing Spondylitis (AS) is the prototype of the axial form of spondyloarthritis. Despite extensive studies, complex mechanisms related to abnormal cellular and molecular processes in AS are not completely understood. Among proinflammatory mediators such as proinflammatory cytokines, NOS-2, chemokines, which lead to inflammation, matrix metalloproteinases (MMPs) play an important role in inflammatory processes that characterize AS. Therefore, we purposed to evaluate whether the disruption of extracellular MMPs inducer (EMMPRIN/CD147), MMPs and tissue inhibitors of MMPs (TIMPs) homeostasis play a role in the evolution of AS especially in patients with a history of Acute Anterior Uveitis (AAU). For this purpose sera from AS patients and from healthy donors (HDs) were assessed for soluble CD147 (sCD147), MMP-3 and TIMP-1 levels using enzyme-linked immunosorbent assay and for the activity of MMP-2 and -9 gelatinases by gelatin zymography. The experimental results showed that the levels of sCD147, MMP-3 and TIMP-1 were significantly increased in AS patients compared to HDs. sCD147 as well as the ratio MMP-2/sCD147 differentiated AS patients with a history of AAU from those without it. The ratios MMP-2/sCD147, MMP-3/sCD147 and MMP-3/TIMP-1 suggested an imbalance between MMPs and their regulators in AS patients. These results suggest that MMPs/sCD147 ratios could be potential biomarkers to strengthen the characterization of AS patients and to predict disease evolution. Positive or negative correlations between some of the experimental and/or clinical features of AS patients and the therapy also highlight the usefulness of the evaluation of these biomarkers to identify an individualized and efficient therapy.

Natural feed contaminant zearalenone decreases the expressions of important pro- and anti-inflammatory mediators and mitogen-activated protein kinase/NF-κB signalling molecules in pigs

Zearalenone (ZEA) is an oestrogenic mycotoxin produced byFusariumspecies, considered to be a risk factor from both public health and agricultural perspectives. In the presentin vivostudy, a feeding trial was conducted to evaluate thein vivoeffect of a ZEA-contaminated diet on immune response in young pigs. The effect of ZEA on pro-inflammatory (TNF-α, IL-8, IL-6, IL-1β and interferon-γ) and anti-inflammatory (IL-10 and IL-4) cytokines and other molecules involved in inflammatory processes (matrix metalloproteinases (MMP)/tissue inhibitors of matrix metalloproteinases (TIMP), nuclear receptors: PPARγ and NF-κB1, mitogen-activated protein kinases (MAPK): mitogen-activated protein kinase kinase kinase 7 (TAK1)/mitogen-activated protein kinase 14 (p38α)/mitogen-activated protein kinase 8 (JNK1)/ mitogen-activated protein kinase 9 (JNK2)) in the liver of piglets was investigated. The present results showed that a concentration of 316 parts per billion ZEA leads to a significant decrease in the levels of pro- and anti-inflammatory cytokines at both gene expression and protein levels, correlated with a decrease in the levels of other inflammatory mediators, MMP and TIMP. The results also showed that dietary ZEA induces a dramatic reduction in the expressions ofNF-κB1andTAK1/p38αMAPK genes in the liver of the experimentally intoxicated piglets, and has no effect on the expression ofPPARγmRNA. The present results suggest that the toxic action of ZEA begins in the upstream of the MAPK signalling pathway by the inhibition of TAK1, a MAPK/NF-κB activator. In conclusion, the present study shows that ZEA alters several important parameters of the hepatic cellular immune response. From an economic point of view, these data suggest that, in pigs, ZEA is not only a powerful oestrogenic mycotoxin but also a potential hepatotoxin when administered through the oral route. Therefore, the present results represent additional data from cellular and molecular levels that could be taken into account in the determination of the regulation limit of the tolerance to ZEA.

The XX sex chromosome complement in mice is associated with increased spontaneous lupus compared with XY

OBJECTIVES

Many autoimmune diseases are characterised by a female predominance. This may be caused by sex hormones, sex chromosomes or both. This report uses a transgenic mouse model to investigate how sex chromosome complement, not confounded by differences in gonadal type, might contribute to lupus pathogenesis.

METHODS

Transgenic NZM2328 mice were created by deletion of the Sry gene from the Y chromosome, thereby separating genetic from gonadal sex. Survival, renal histopathology and markers of immune activation were compared in mice carrying the XX versus the XY(-) sex chromosome complement, with each genotype being ovary bearing.

RESULTS

Mice with XX sex chromosome complement compared with XY(-) exhibited poorer survival rates and increased kidney pathology. Splenic T lymphocytes from XX mice demonstrated upregulated X-linked CD40 ligand expression and higher levels of activation markers ex vivo. Increased MMP, TGF and IL-13 production was found, while IL-2 was lower in XX mice. An accumulation of splenic follicular B cells and peritoneal marginal zone B cells was observed, coupled with upregulated costimulatory marker expression on B cells in XX mice.

CONCLUSION

These data show that the XX sex chromosome complement, compared with XY(-), is associated with accelerated spontaneous lupus.

CD147 (Basigin/Emmprin) identifies FoxP3+CD45RO+CTLA4+-activated human regulatory T cells

Human CD4+FoxP3+ T cells are functionally and phenotypically heterogeneous providing plasticity to immune activation and regulation. To better understand the functional dynamics within this subset, we first used a combined strategy of subcellular fractionation and proteomics to describe differences at the protein level between highly purified human CD4+CD25+ and CD4+CD25− T-cell populations. This identified a set of membrane proteins highly expressed on the cell surface of human regulatory T cells (Tregs), including CD71, CD95, CD147, and CD148. CD147 (Basigin or Emmprin) divided CD4+CD25+ cells into distinct subsets. Furthermore, CD147, CD25, FoxP3, and in particular CTLA-4 expression correlated. Phenotypical and functional analyses suggested that CD147 marks the switch between resting (CD45RA+) and activated (CD45RO+) subsets within the FoxP3+ T-cell population. Sorting of regulatory T cells into CD147− and CD147+ populations demonstrated that CD147 identifies an activated and highly suppressive CD45RO+ Treg subset. When analyzing CD4+ T cells for their cytokine producing potential, CD147 levels grouped the FoxP3+ subset into 3 categories with different ability to produce IL-2, TNF-α, IFN-γ, and IL-17. Together, this suggests that CD147 is a direct marker for activated Tregs within the CD4+FoxP3+ subset and may provide means to manipulate cells important for immune homeostasis.

Fibrosis in endstage human heart failure: severe changes in collagen metabolism and MMP/TIMP profiles

OBJECTIVES

We studied fibrosis, collagen metabolism, MMPs/TIMPs and cytokine expression in various forms of human heart failure (HF) by quantitative immunofluorescent microscopy, Western blot, zymography, RT-PCR and in situ hybridization. In explanted human hearts with HF due to either dilated (DCM, n=6) or ischemic (ICM-BZ-borderzone, ICM-RZ-remote zone, n=7) or inflammatory (myocarditis, MYO, n=6) cardiomyopathy and 8 controls MMP2, 8, 9, 19, and TIMP1, 2, 3, 4 as well as procollagens I and III (PINP, PIIINP), mature collagen III (IIINTP) and the cross-linked collagen I degradation product (ICTP) were measured.

RESULTS

In comparison with controls, MMPs and TIMPs were significantly upregulated ranging (from highest to lowest) from ICM-BZ, DCM, ICM-RZ, MYO for all MMPs with the exception of MMP9 (highest in DCM), and for TIMPs from ICM-BZ, ICM-RZ, DCM and MYO. MMP2 and 9 were activated in all groups. The TIMP/MMP ratio was 1.3 for control, 1.9 in ICM-BZ (TIMP>MMP) and lowered to 1.0 in the other groups. Collagen I/collagen III ratio correlated significantly with the decrease in LVEDP. PINP was higher than ICTP in all groups. PIIINP elevation was present in DCM and ICM-RZ and IIINTP was up to 4-fold augmented in all groups. Fibrosin mRNA was upregulated in ICM-BZ, activin A in MYO but FGF1 and FGF2 remained unchanged. ANP mRNA was increased in all groups.

CONCLUSIONS

Although different degrees of severity of collagen metabolism, MMP/TIMP imbalance and cytokine expression in diverse forms of HF are present, the end product is collagen deposition. These findings suggest multiple mechanisms acting alone or in concert in fibrosis development in HF.

Matrix metalloproteinases in cytotoxic lymphocytes impact on tumour infiltration and immunomodulation

To efficiently combat solid tumours, endogenously or adoptively transferred cytotoxic T cells and natural killer (NK) cells, need to leave the vasculature, traverse the interstitium and ultimately infiltrate the tumour mass. During this locomotion and migration in the three dimensional environment many obstacles need to be overcome, one of which is the possible impediment of the extracellular matrix. The first and obvious one is the sub-endothelial basement membrane but the infiltrating cells will also meet other, both loose and tight, matrix structures that need to be overridden. Matrix metalloproteinases (MMPs) are believed to be one of the most important endoprotease families, with more than 25 members, which together have function on all known matrix components. This review summarizes what is known on synthesis, expression patterns and regulation of MMPs in cytotoxic lymphocytes and their possible role in the process of tumour infiltration. We also discuss different functions of MMPs as well as the possible use of other lymphocyte proteases for matrix degradation.

The many faces of EMMPRIN - roles in neuroinflammation

The central nervous system (CNS) is a relatively immune-privileged organ, wherein a well-instated barrier system (the blood-brain barrier) prevents the entry of blood cells into the brain with the exception of regular immune surveillance cells. Despite this tight security immune cells are successful in entering the CNS tissue where they result in states of neuroinflammation, tissue damage and cell death. Various components of the blood-brain barrier and infiltrating cells have been examined to better understand how blood cells are able to breach this secure barrier. Proteases, specifically matrix metalloproteinases (MMP), have been found to be the common culprits in most diseases involving neuroinflammation. MMPs secreted by infiltrating cells act specifically upon targets on various components of the blood-brain barrier, compromising this barrier and allowing cell infiltration into the CNS. Extracellular matrix metalloproteinase inducer (EMMPRIN) is an upstream inducer of several MMPs and is suggested to be the master regulator of MMP production in disease states such as cancer metastasis. EMMPRIN in the context of the CNS is still relatively understudied. In this review we will introduce EMMPRIN, discuss its ligands and roles in non-CNS conditions that can help implicate its involvement in CNS disorders, showcase its expression within the CNS in healthy and disease conditions, elucidate its ligands and receptors, and briefly discuss the emerging roles it plays in various diseases of the CNS involving inflammation.

Functional selection of phagocytosis-promoting genes: cell sorting-based selection

Phagocytosis is a critical host defense mechanism that clears invading pathogens, apoptotic cells, and cell debris; it is an essential process for normal development, tissue remodeling, immune response, and inflammation. Here, a functional selection strategy was used to isolate novel phagocytosis-promoting genes. After the retroviral transfer of mouse brain cDNA library into NIH3T3 mouse fibroblast cells, cell sorting was used to select the cells that phagocytosed fluorescent zymosan particles. The cDNAs were retrieved from the selected cells and identified by DNA sequencing as eIF5A, Meg3, Tubb5, Sparcl-1, Uchl-1, Bsg (CD147), Ube2v1, and Pamr1. The phagocytosis-promoting activity for some of these cDNAs was confirmed by transient transfection in the independent phagocytosis assays. Thus, the unbiased selection procedure successfully identified multiple phagocytosis-promoting genes. The selection method can be applied to other cell-based assays where cells with a desired phenotype can be physically separated. Moreover, the new gene targets uncovered in this study could be relevant to biomolecule screening in search of phagocytosis-regulating agents. In a small-scale screen, a series of imidazopyridine compounds was tested to identify the small molecules that modulate eIF5A-mediated phagocytic activity. Several compounds that influenced the phagocytic activity can be further used as chemical-genetic tools to delineate the mechanisms of eIF5A action and be potential drug candidates that are capable of therapeutically modulating phagocytic activity.

Involvement of HAb18G/CD147 in T cell activation and immunological synapse formation

HAb18G/CD147, a glycoprotein of the immunoglobulin super-family (IgSF), is a T cell activation-associated molecule. In this report, we demonstrated that HAb18G/CD147 expression on both activated CD4⁺ and CD8⁺ T cells was up-regulated. In vitro cross-linking of T cells with an anti-HAb18G/CD147 monoclonal antibody (mAb) 5A12 inhibited T cells proliferation upon T cell receptor stimulation. Such co-stimulation inhibited T cell proliferation by down-regulating the expression of CD25 and interleukin-2 (IL-2), decreased production of IL-4 but not interferon-γ. Laser confocal imaging analysis indicated that HAb18G/CD147 was recruited to the immunological synapse (IS) during T cell activation; triggering HAb18G/CD147 on activated T cells by anti-HAb18G/CD147 mAb 5A12 strongly dispersed the formation of the IS. Further functional studies showed that the ligation of HAb18G/CD147 with mAb 5A12 decreased the tyrosine phosphorylation and intracellular calcium mobilization levels of T cells. Through docking antibody–antigen interactions, we demonstrated that the function of mAb 5A12 is tightly dependent on its specificity of binding to N-terminal domain I, which plays pivotal role in the oligomerization of HAb18G/CD147. Taken together, we provide evidence that HAb18G/CD147 could act as a co-stimulatory receptor to negatively regulate T cell activation and is functionally linked to the formation of the IS.

Cyclophilin-CD147 interactions: a new target for anti-inflammatory therapeutics

CD147 is a widely expressed plasma membrane protein that has been implicated in a variety of physiological and pathological activities. It is best known for its ability to function as extracellular matrix metalloproteinase inducer (hence the other name for this protein, EMMPRIN), but has also been shown to regulate lymphocyte responsiveness, monocarboxylate transporter expression and spermatogenesis. These functions reflect multiple interacting partners of CD147. Among these CD147-interacting proteins cyclophilins represent a particularly interesting class, both in terms of structural considerations and potential medical implications. CD147 has been shown to function as a signalling receptor for extracellular cyclophilins A and B and to mediate chemotactic activity of cyclophilins towards a variety of immune cells. Recent studies using in vitro and in vivo models have demonstrated a role for cyclophilin-CD147 interactions in the regulation of inflammatory responses in a number of diseases, including acute lung inflammation, rheumatoid arthritis and cardiovascular disease. Agents targeting either CD147 or cyclophilin activity showed significant anti-inflammatory effects in experimental models, suggesting CD147-cyclophilin interactions may be a good target for new anti-inflammatory therapeutics. Here, we review the recent literature on different aspects of cyclophilin-CD147 interactions and their role in inflammatory diseases.

Upregulation of HAb18G/CD147 in activated human umbilical vein endothelial cells enhances the angiogenesis

Previous studies demonstrated that CD147 molecule, highly expressed on the surface of various malignant tumor cells, significantly correlated with the malignancy of these cancers; however, the role of HAb18G/CD147 in endothelial cells has yet to be established. In this study, we found that the expression of HAb18G/CD147 was significantly upregulated in activated HUVECs. The inhibition of HAb18G/CD147 expression by specific siRNA led to significantly decreased angiogenesis in vitro. Our data indicate that HAb18G/CD147 may regulate angiogenesis via several mechanisms including proliferation, survival, migration, MMPs secretion, and PI3K/Akt activation. Our findings for the first time suggest that upregulation of HAb18G/CD147 in activated HUVECs might play an important role in angiogenesis.

Targeting the chemotactic function of CD147 reduces collagen-induced arthritis

CD147 is a type I transmembrane glycoprotein expressed on a wide variety of cell types, including all leucocytes. While CD147 is best known as a potent inducer of matrix metalloproteinases, it can also function as a regulator of leucocyte migration through its cell surface interaction with chemotactic extracellular cyclophilins. A potential role for CD147-cyclophilin interactions during inflammatory diseases, including rheumatoid arthritis (RA), is suggested from several studies. For example, CD147 expression is increased on reactive leucocytes in the synovial fluid and tissues of patients with arthritis. In addition, the synovial fluid of patients with RA contains high levels of extracellular cyclophilin A. In the current studies we investigated the contribution of the chemotactic function of CD147-cyclophilin interactions to joint inflammation using the mouse model of collagen-induced arthritis. Our data demonstrate that proinflammatory leucocytes, specifically neutrophils, monocytes and activated CD4(+) T cells, lose their ability to migrate in response to cyclophilin A in vitro when treated with anti-CD147 monoclonal antibody. Furthermore, in vivo treatment with anti-CD147 monoclonal antibody can reduce the development of collagen-induced arthritis in mice by >75%. Such findings suggest that CD147-cyclophilin interactions might contribute to the pathogenesis of RA by promoting the recruitment of leucocytes into joint tissues.

Atrial extracellular matrix remodelling in patients with atrial fibrillation

Atrial fibrillation (AF) is the most frequent clinical arrhythmia. Atrial fibrosis is an important factor in initiating and maintaining AF. However, the collagen turnover and its regulation in AF has not been completely elucidated. We tested the hypothesis that the extracellular matrix changes are more severe in patients with permanent AF in comparison with those in patients in sinus rhythm (SR). Intraoperative biopsies from the right atrial appendages (RAA) and free walls (RFW) from 24 patients with AF undergoing a mini-Maze procedure and 24 patients in SR were investigated with qualitative and quantitative immunofluorescent and Western blot analyses. As compared with SR, all patients with AF exhibited dysregulations in collagen type I and type III synthesis/degradation. Tissue inhibitors of metalloproteinases (TIMP2) was significantly enhanced only in RAA-AF. As compared with SR, collagen VI, matrix metalloproteinases MMP2, MMP9 and TIMP1 were significantly increased while TIMP3 and TIMP4 remained unchanged in all AF groups. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a newly discovered MMPs inhibitor, was elevated in RFW as compared to RAA-AF (P<0.05) and RFW-SR (P<0.05). The level of transforming growth factor (TGF)-β1 was higher in AF than SR. Smad2 and phosphorylated Smad2 showed an elevation in RFW-AF as compared to RFW-SR, RAA-AF, and RAA-SR groups (P<0.05). Conclusions: Atrial fibrosis in AF is characterized by severe alterations in collagen I and III synthesis/degradation associated with disturbed MMP/TIMP systems and increased levels of RECK. TGF-β1 contributes to atrial fibrosis via TGF-β1-Smad pathway by phospho-rylating Smad2. These processes culminate in accumulations of fibrillar and non-fibrillar collagens leading to excessive atrial fibrosis and maintainance of AF.

CD147 inhibits the nuclear factor of activated T-cells by impairing Vav1 and Rac1 downstream signaling

CD147 is a transmembrane protein that plays crucial roles in the development and function of the reproductive, visual, and nervous systems. CD147 also exerts positive and negative actions in T-cells by still obscure mechanisms. In this study, we have analyzed the expression, localization, and function of CD147 during T-cell receptor signaling responses. We show here that CD147 is an integral component of the T-cell immune synapse and that its overexpression leads to the inhibition of NF-AT (nuclear factor of activated T-cells) activity induced by Vav1, a Rac1 exchange factor. This inhibitory activity is mediated by the CD147 intracellular tail and is totally independent of its extracellular or transmembrane regions. The molecular dissection of the influence of CD147 on the Vav1 pathway indicates that its inhibitory action takes place downstream of Vav1 and Rac1 but upstream of the serine/threonine kinases JNK and Pak1. The interference of CD147 with these pathways is highly specific because the overexpression of CD147 does not affect the activity of other GDP/GTP exchange factors or the stimulation of the ERK cascade. Finally, we show that the CD147 knockdown in Jurkat cells promotes higher levels of NF-AT stimulation and Pak1 phosphorylation upon T-cell receptor cross-linking. Instead, the lack of CD147 does not affect other signaling cascades that participate in the same cellular response. Taken together, these results indicate that CD147, via the selective inhibition of specific downstream elements of the Vav1/Rac1 route, contributes to the negative regulation of T-cell responses.

CD147 immunoglobulin superfamily receptor function and role in pathology

The immunoglobulin superfamily member CD147 plays an important role in fetal, neuronal, lymphocyte and extracellular matrix development. Here we review the current understanding of CD147 expression and protein interactions with regard to CD147 function and its role in pathologic conditions including heart disease, Alzheimer's disease, stroke and cancer. A model linking hypoxic conditions found within the tumor microenvironment to upregulation of CD147 expression and tumor progression is introduced.