The pattern recognition receptor PTX3 is recruited at the synapse between dying and dendritic cells, and edits the cross-presentation of self, viral, and tumor antigens

Role of long pentraxin PTX3 in cancer

Cancer has become a leading cause of death and disease burden worldwide, closely related to rapid socioeconomic development. However, the fundamental reason is the lack of comprehensive understanding of the mechanism of cancer, accurate identification of preclinical cancer, and effective treatment of the disease. Therefore, it is particularly urgent to study specific mechanisms of cancer and develop effective prediction and treatment methods. Long Pentraxin PTX3 is a soluble pattern recognition molecule produced by various cells in inflammatory sites, which plays a role as a promoter or suppressor of cancer in multiple tumors through participating in innate immune response, neovascularization, energy metabolism, invasion, and metastasis mechanisms. Based on this, this article mainly reviews the role of PTX3 in various cancers.

PTX3 shapes profibrotic immune cells and epithelial/fibroblast repair and regeneration in a murine model of pulmonary fibrosis

The long pentraxin 3 (PTX3) is protective in different pathologies but was not analyzed in-depth in Idiopathic Pulmonary Fibrosis (IPF). Here, we have explored the influence of PTX3 in the bleomycin (BLM)-induced murine model of IPF by looking at immune cells (macrophages, mast cells, T cells) and stemness/regenerative markers of lung epithelium (SOX2) and fibro-blasts/myofibroblasts (CD44) at different time points that retrace the progression of the disease from onset at day 14, to full-blown disease at day 21, to incomplete regression at day 28. We took advantage of transgenic PTX3 overexpressing mice (Tie2-PTX3) and Ptx3 null ones (PTX3-KO) in which pulmonary fibrosis was induced. Our data have shown that PTX3 overexpression in Tie2-PTX3 compared to WT or PTX3-KO: reduced CD68+ and CD163+ macrophages and the Tryptase+ mast cells during the whole experimental time; on the contrary, CD4+ T cells are consistently present on day 14 and dramatically decreased on day 21; CD8+ T cells do not show significant differences on day 14, but are significantly reduced on day 21; SOX2 is reduced on days 14 and 21; CD44 is reduced on day 21. Therefore, PTX3 could act on the proimmune and fibrogenic microenvironment to prevent fibrosis in BLM-treated mice.

Leveraging Tumor Microenvironment Infiltration in Pancreatic Cancer to Identify Gene Signatures Related to Prognosis and Immunotherapy Response

The hallmark of pancreatic ductal adenocarcinoma (PDAC) is an exuberant tumor microenvironment (TME) comprised of diverse cell types that play key roles in carcinogenesis, chemo-resistance, and immune evasion. Here, we propose a gene signature score through the characterization of cell components in TME for promoting personalized treatments and further identifying effective therapeutic targets. We identified three TME subtypes based on cell components quantified by single sample gene set enrichment analysis. A prognostic risk score model (TMEscore) was established based on TME-associated genes using a random forest algorithm and unsupervised clustering, followed by validation in immunotherapy cohorts from the GEO dataset for its performance in predicting prognosis. Importantly, TMEscore positively correlated with the expression of immunosuppressive checkpoints and negatively with the gene signature of T cells' responses to IL2, IL15, and IL21. Subsequently, we further screened and verified F2R-like Trypsin Receptor1 (F2RL1) among the core genes related to TME, which promoted the malignant progression of PDAC and has been confirmed as a good biomarker with therapeutic potential in vitro and in vivo experiments. Taken together, we proposed a novel TMEscore for risk stratification and selection of PDAC patients in immunotherapy trials and validated effective pharmacological targets.

Pan-Cancer Analysis of Pentraxin 3: A Potential Biomarker of COVID-19

Pentraxin 3 (PTX3), a potential biomarker of the severity and mortality of COVID-19 patients, is aberrantly expressed in human tumors. However, a comprehensive pan-cancer analysis of PTX3 remains to be elucidated. PTX3 data profiles and clinical information in TCGA cancers were obtained from different public databases to clarify the expression levels, genetic alterations, prognostic significance, underlying mechanisms, and the predicted role in immunotherapy of PTX3 across TCGA cancers. Our analyses showed that PTX3 was aberrantly expressed in most tumors and was significantly related to prognosis and tumor stage. Interaction network and enrichment analyses revealed that PTX3 participated in tumor immuno-related progression. In addition, PTX3 levels were critically associated with immune cell components and immune scores, and PTX3 strongly coexpressed with immune-related genes in TCGA cancers. Meanwhile, PTX3 expression was associated with immune checkpoint genes, and immunotherapy potential biomarkers in multiple cancers, predicting special immunotherapy responses in different tumor types. In kidney renal clear cell carcinoma (KIRC), PTX3 emerged as an independent prognostic factor through multivariable Cox regression analyses. Blocking PTX3 with siRNA could suppress the growth of KIRC cells and invasion. Conclusively, our study shows a comprehensive bioinformatic analysis of PTX3, which might serve as a pan-cancer prognostic biomarker.

Tumor cell-based vaccine: an effective strategy for eradication of cancer cells

Whole tumor cell-based vaccines include all potential antigen-rich cell lysates to target a specific type of tumor without the need to find the best antigen candidate in protein- or peptide-based vaccines. Preparation of whole tumor cell lysates inducing cell death and inactivating immunosuppressive cytokine secretion from the tumor cells is highly enviable. Generally, modified whole tumor cells, tumor cell-derived exosomes, autologous tumor cell-derived ribonucleic acid, and personalized mutanome-derived tumor antigen are promising immunotherapeutic approaches. Autologous dendritic cells loaded with tumor-associated antigens also induce the generation of immunological memory and antitumor response as an effective method for the treatment of cancer. The present review briefly describes tumor cell-based vaccines as a promising strategy for eradication of cancer cells.

Novel Soluble Mediators of Innate Immune System Activation in Solid Allograft Rejection

During the past years, solid allograft rejection has been considered the consequence of either cellular- or antibody-mediated reaction both being part of the adaptive immune response, whereas the role of innate immunity has been mostly considered less relevant. Recently, a large body of evidence suggested that the innate immune response and its soluble mediators may play a more important role during solid allograft rejection than originally thought. This review will highlight the role of novel soluble mediators that are involved in the activation of innate immunity during alloimmune response and solid allograft rejection. We will also discuss emerging strategies to alleviate the aforementioned events. Hence, novel, feasible, and safe clinical therapies are needed to prevent allograft loss in solid organ transplantation. Fully understanding the role of soluble mediators of innate immune system activation may help to mitigate solid allograft rejection and improve transplanted recipients' outcomes.

PTX3 Regulation of Inflammation, Hemostatic Response, Tissue Repair, and Resolution of Fibrosis Favors a Role in Limiting Idiopathic Pulmonary Fibrosis

PTX3 is a soluble pattern recognition molecule (PRM) belonging to the humoral innate immune system, rapidly produced at inflammatory sites by phagocytes and stromal cells in response to infection or tissue injury. PTX3 interacts with microbial moieties and selected pathogens, with molecules of the complement and hemostatic systems, and with extracellular matrix (ECM) components. In wound sites, PTX3 interacts with fibrin and plasminogen and favors a timely removal of fibrin-rich ECM for an efficient tissue repair. Idiopathic Pulmonary Fibrosis (IPF) is a chronic and progressive interstitial lung disease of unknown origin, associated with excessive ECM deposition affecting tissue architecture, with irreversible loss of lung function and impact on the patient’s life quality. Maccarinelli et al. recently demonstrated a protective role of PTX3 using the bleomycin (BLM)-induced experimental model of lung fibrosis, in line with the reported role of PTX3 in tissue repair. However, the mechanisms and therapeutic potential of PTX3 in IPF remained to be investigated. Herein, we provide new insights on the possible role of PTX3 in the development of IPF and BLM-induced lung fibrosis. In mice, PTX3-deficiency was associated with worsening of the disease and with impaired fibrin removal and subsequently increased collagen deposition. In IPF patients, microarray data indicated a down-regulation of PTX3 expression, thus suggesting a potential rational underlying the development of disease. Therefore, we provide new insights for considering PTX3 as a possible target molecule underlying therapeutic intervention in IPF.

Perspectives on long pentraxin 3 and rheumatoid arthritis: several potential breakthrough points relying on study foundation of the past

Rheumatoid arthritis (RA) is a systemic chronic autoimmune inflammatory disease which is mainly characterized by synovitis and results in a severe burden for both the individual and society. To date, the underlying mechanisms of RA are still poorly understood. Pentraxin 3 (PTX3) is a typical long pentraxin protein which has been highly conserved during evolution. Meanwhile, functions as well as properties of PTX3 have been extensively studied. Several studies identified that PTX3 plays a predominate role in infection, inflammation, immunity and tumor. Interestingly, PTX3 has also been verified to be closely associated with development of RA. We therefore accomplished an elaboration of the relationships between PTX3 and RA. Herein, we mainly focus on the associated cell types and cognate cytokines involved in RA, in combination with PTX3. This review infers the insight into the interaction of PTX3 in RA and aims to provide novel clues for potential therapeutic target of RA in clinic.

Immunization with Pentraxin3 prevents transition from subclinical to clinical lupus nephritis in lupus-prone mice: Insights from renal ultrastructural findings

BACKGROUND

Pentraxin3 (PTX3) is an emerging player in lupus nephritis (LN). Anti-PTX3 antibodies showed to delay LN occurrence in vivo.

AIM

To evaluate renal changes following immunization with PTX3 in a murine model of LN.

MATERIALS AND METHODS

Twenty-two lupus-prone New Zealand Black/White (NZB/W)F1 mice were divided into two groups (n = 11) and subcutaneously injected with human recombinant (hr)PTX3 100 μg or phosphate buffer saline (PBS) 200 μl, three times 3 weeks apart, starting before development of proteinuria. Five mice from each group were scheduled for sacrifice at week 22 and 6 from each group at week 29. Renal lesions included electron-dense deposits (EDD), glomerular deposition of IgG, complement and PTX3 as markers of renal inflammation. They were evaluated by immunofluorescence (IF), confocal and immunoelectron microscopy (IEM). Validated semiquantitative scores were used when available to score renal lesions. Chi-squared test with Fisher exact test was used for comparison.

RESULTS

Nineteen out of 22 mice were sacrificed as scheduled. Only hrPTX3-immunized mice developed anti-PTX3 antibodies. Compared to PBS-injected mice, they displayed a dramatic decrease in glomerular deposits of IgG, C1q and PTX3, as well as in the amount of EDD (p = 0.006) and podocyte effacement (p = 0.043). Importantly, PTX3 was pinpointed inside the EDD and co-localized with nuclear material.

CONCLUSIONS

Immunization with PTX3 prevented progression from the preclinical to the clinical stage of LN, inciting anti-PTX3 antibodies and preventing renal PTX3 deposition. PTX3 is a novel component of EDD, submitting it as one initiating autoantigen in LN and as potential target for early treatment.

Pentraxin 3 deficiency exacerbates lipopolysaccharide-induced inflammation in adipose tissue

BACKGROUND/OBJECTIVES

Pentraxin 3 (PTX3) has been characterized as a soluble and multifunctional pattern recognition protein in the regulation of innate immune response. However, little is known about its role in adipose tissue inflammation and obesity. Herein, we investigated the role of PTX3 in the regulation of lipopolysaccharide (LPS)-induced inflammation in adipocytes and adipose tissue, as well as high-fat diet (HFD)-induced metabolic inflammation in obesity.

METHODS

Ptx3 knockdown 3T3-L1 Cells were generated using shRNA for Ptx3 gene and treated with different inflammatory stimuli. For the in vivo studies, Ptx3 knockout mice were treated with 0.3 mg/kg of LPS for 6 h. Adipose tissues were collected for gene and protein expression by qPCR and western blotting, respectively. Ptx3 knockout mice were fed with HFD for 12 week since 6 week of age.

RESULTS

We observed that the expression of PTX3 in adipose tissue and serum PTX3 were markedly increased in response to LPS administration. Knocking down Ptx3 in 3T3-L1 cells reduced adipogenesis and caused a more profound and sustained upregulation of proinflammatory gene expression and signaling pathway activation during LPS-stimulated inflammation in 3T3-L1 adipocytes. In vivo studies showed that PTX3 deficiency significantly exacerbated the LPS-induced upregulation of inflammatory genes and downregulation of adipogeneic genes in visceral and subcutaneous adipose tissue of mice. Accordingly, LPS stimulation elicited increased activation of nuclear factor-κB (NF-κB) and p44/42 MAPK (Erk1/2) signaling pathways in visceral and subcutaneous adipose tissue. The expression of PTX3 in adipose tissue was also induced by HFD, and PTX3 deficiency led to the upregulation of proinflammatory genes in visceral adipose tissue of HFD-induced obese mice.

CONCLUSIONS

Our results suggest a protective role of PTX3 in LPS- and HFD-induced sustained inflammation in adipose tissue.

PTX3 Intercepts Vascular Inflammation in Systemic Immune-Mediated Diseases

PTX3 is a prototypic soluble pattern recognition receptor, expressed at sites of inflammation and involved in regulation of the tissue homeostasis. PTX3 systemic levels increase in many (but not all) immune-mediated inflammatory conditions. Research on PTX3 as a biomarker has so far focused on single diseases. Here, we performed a multi-group comparative study with the aim of identifying clinical and pathophysiological phenotypes associated with PTX3 release. PTX3 concentration was measured by ELISA in the plasma of 366 subjects, including 96 patients with giant cell arteritis (GCA), 42 with Takayasu's arteritis (TA), 10 with polymyalgia rheumatica (PMR), 63 with ANCA-associated systemic small vessel vasculitides (AAV), 55 with systemic lupus erythematosus (SLE), 21 with rheumatoid arthritis (RA) and 79 healthy controls (HC). Patients with SLE, AAV, TA and GCA, but not patients with RA and PMR, had higher PTX3 levels than HC. PTX3 concentration correlated with disease activity, acute phase reactants and prednisone dose. It was higher in females, in patients with recent-onset disease and in those with previous or current active vasculitis at univariate analysis. Active small- or large- vessel vasculitis were the main independent variables influencing PTX3 levels at multivariate analysis. High levels of PTX3 in the blood can contribute to identify an increased risk of vascular involvement in patients with systemic immune-mediated diseases.

Burning controversies in NETs and autoimmunity: The mysteries of cell death and autoimmune disease

The causes and mechanisms of autoimmune disease pose continuing challenges to the scientific community. Recent clues implicate a peculiar feature of neutrophils, their ability to release nuclear chromatin in the form of neutrophil extracellular traps (NETs), in the induction or progression of autoimmune disease. Efforts to define the beneficial versus detrimental effects of NET release have, as yet, only partially revealed mechanisms that guide this process. Evidence suggests that the process of NET release is highly regulated, but the details of regulation remain controversial and obscure. Without a better understanding of the factors that initiate and control NET formation, the judicious modification of neutrophil behaviour for medically useful purposes appears remote. We highlight gaps and inconsistencies in published work, which make NETs and their role in health and disease a puzzle that deserves more focused attention.

The long pentraxin PTX3: A prototypical sensor of tissue injury and a regulator of homeostasis

Tissue damage frequently occurs. The immune system senses it and enforces homeostatic responses that lead to regeneration and repair. The synthesis of acute phase molecules is emerging as a crucial event in this program. The prototypic long pentraxin PTX3 orchestrates the recruitment of leukocytes, stabilizes the provisional matrix in order to facilitate leukocyte and stem progenitor cells trafficking, promotes swift and safe clearance of dying cells and of autoantigens, limiting autoimmunity and protecting the vasculature. These non-redundant actions of PTX3 are necessary for the resolution of inflammation. Recent studies have highlighted the mechanisms by which PTX3 adapts the functions of innate immune cells, orchestrates tissue repair and contributes to select the appropriate acquired immune response in various tissues. Conversely, PTX3 continues to be produced in diseases where the inflammatory response does not resolve. It is therefore a valuable biomarker for more precise and personalized stratification of patients, often independently predicting clinical evolution and outcome. There is strong promise for novel therapies based on understanding the mechanisms with which PTX3 plays its homeostatic role, especially in regulating leukocyte migration and the resolution of inflammatory processes.

Essential PTX3 Biology (not only) for Cardiologists and Cardiac Surgeons

Inflammation has been recognized to form an integral part of the atherosclerotic process. Much consideration has been given lately to the role played in atherogenesis by C-reactive protein (CRP). Although not accepted unequivocally, CRP appears to be not only a marker, but also an active mediator of the atherosclerotic process. Pentraxin 3 (PTX3) is a newly identified acute phase reactant which shares some structural and some functional properties with CRP. On the other hand, pentraxin 3 displays unique biological properties of its own, including a possible role in the pathogenesis of cardiovascular diseases and in processes accompanying the natural evolution of surgical wounds. This review article discusses recent information concerning basic pentraxin 3 biology in inflammation and in innate immunity reactions as viewed by a cardiologist in the context of acute coronary events and by a surgeon in patients struck with multiple wounds who are at the same time menaced by bacterial infections.

The Neutrophil's Choice: Phagocytose vs Make Neutrophil Extracellular Traps

Neutrophils recognize particulate substrates of microbial or endogenous origin and react by sequestering the cargo via phagocytosis or by releasing neutrophil extracellular traps (NETs) outside the cell, thus modifying and alerting the environment and bystander leukocytes. The signals that determine the choice between phagocytosis and the generation of NETs are still poorly characterized. Neutrophils that had phagocytosed bulky particulate substrates, such as apoptotic cells and activated platelets, appear to be “poised” in an unresponsive state. Environmental conditions, the metabolic, adhesive and activation state of the phagocyte, and the size of and signals associated with the tethered phagocytic cargo influence the choice of the neutrophils, prompting either phagocytic clearance or the generation of NETs. The choice is dichotomic and apparently irreversible. Defects in phagocytosis may foster the intravascular generation of NETs, thus promoting vascular inflammation and morbidities associated with diseases characterized by defective phagocytic clearance, such as systemic lupus erythematosus. There is a strong potential for novel treatments based on new knowledge of the events determining the inflammatory and pro-thrombotic function of inflammatory leukocytes.

Long pentraxin 3: A novel multifaceted player in cancer

Since its discovery in 1992, long pentraxin 3 (PTX3) has been characterized as soluble patter recognition receptor, a key player of the innate immunity arm with non-redundant functions in pathogen recognition and inflammatory responses. As a component of the extra-cellular matrix milieu, PTX3 has been implicated also in wound healing/tissue remodeling, cardiovascular diseases, fertility, and infectious diseases. Consequently, PTX3 levels in biological fluids have been proposed as a fluid-phase biomarker in different pathological conditions. In the last decade, experimental evidences have shown that PTX3 may exert a significant impact also on different aspects of cancer biology, including tumor onset, angiogenesis, metastatic dissemination and immune-modulation. However, it remains unclear whether PTX3 acts as a good cop or bad cop in cancer. In this review, we will summarize and discuss the scientific literature data focusing on the role of PTX3 in experimental and human tumors, including its putative translational implications.

Immune Cytolytic Activity Stratifies Molecular Subsets of Human Pancreatic Cancer

Purpose: Immunotherapy has the potential to improve the dismal prognosis in pancreatic ductal adenocarcinoma (PDA), but clinical trials, including those with single-agent PD-1 or PD-L1 inhibition, have been disappointing. Our aim was to examine the immune landscape of PDA as it relates to aspects of tumor biology, including neoepitope burden.Experimental Design: We used publicly available expression data from 134 primary resection PDA samples from The Cancer Genome Atlas to stratify patients according to a cytolytic T-cell activity expression index. We correlated cytolytic immune activity with mutational, structural, and neoepitope features of the tumor.Results: Human PDA displays a range of intratumoral cytolytic T-cell activity. PDA tumors with low cytolytic activity exhibited significantly increased copy number alterations, including recurrent amplifications of MYC and NOTCH2 and recurrent deletions and mutations of CDKN2A/B In sharp contrast to other tumor types, high cytolytic activity in PDA did not correlate with increased mutational burden or neoepitope load (MHC class I and class II). Cytolytic-high tumors exhibited increased expression of multiple immune checkpoint genes compared to cytolytic-low tumors, except for PD-L1 expression, which was uniformly low.Conclusions: These data identify a subset of human PDA with high cytolytic T-cell activity. Rather than being linked to mutation burden or neoepitope load, immune activation indices in PDA were inversely linked to genomic alterations, suggesting that intrinsic oncogenic processes drive immune inactivity in human PDA. Furthermore, these data highlight the potential importance of immune checkpoints other than PD-L1/PD-1 as therapeutic targets in this lethal disease. Clin Cancer Res; 23(12); 3129-38. ©2016 AACR.

Tunicamycin-induced Endoplasmic Reticulum Stress Upregulates the Expression of Pentraxin 3 in Human Retinal Pigment Epithelial Cells

PURPOSE

To investigate the production of long pentraxin 3 (PTX3) in response to tunicamycin-induced endoplasmic reticulum (ER) stress and its role in ER stress-associated cell death, PTX3 expression was evaluated in the human retinal pigment epithelial cell line, ARPE-19.

METHODS

PTX3 production in ARPE-19 cells was analyzed in the absence or presence of tunicamycin treatment by enzyme-linked immunosorbent assay. PTX3 protein and mRNA levels were estimated using western blot analysis and real-time reverse transcription-polymerase chain reaction, respectively. Protein and mRNA levels of CCAAT-enhancer-binding protein homologous protein (CHOP) and ARPE-19 cell viability were measured in the presence of tunicamycin-induced ER stress in control or PTX3 small hairpin RNA (shRNA)-transfected ARPE-19 cells.

RESULTS

The protein and mRNA levels of PTX3 were found to be significantly increased by tunicamycin treatment. PTX3 production was significantly decreased in inositol-requiring enzyme 1α shRNA-transfected ARPE-19 cells compared to control shRNA-transfected cells. Furthermore, pretreatment with the NF-κB inhibitor abolished tunicamycin-induced PTX3 production. Decreased cell viability and prolonged protein and mRNA expression of CHOP were observed under tunicamycin-induced ER stress in PTX3 shRNA transfected ARPE-19 cells.

CONCLUSIONS

These results suggest that PTX3 production increased in the presence of tunicamycin-induced ER stress. Therefore, PTX3 could be an important protector of ER stress-induced cell death in human retinal pigment epithelial cells. Inositol-requiring enzyme 1α and the NF-κB signaling pathway may serve as potential targets for regulation of PTX3 expression in the retina. Therefore, their role in PTX3 expression needs to be further investigated.

Acute phase response in amputated tail stumps and neural tissue-preferential expression in tail bud embryos of the Xenopus neuronal pentraxin I gene

Regeneration of lost organs involves complex processes, including host defense from infection and rebuilding of lost tissues. We previously reported that Xenopus neuronal pentraxin I (xNP1) is expressed preferentially in regenerating Xenopus laevis tadpole tails. To evaluate xNP1 function in tail regeneration, and also in tail development, we analyzed xNP1 expression in tailbud embryos and regenerating/healing tails following tail amputation in the 'regeneration' period, as well as in the 'refractory' period, when tadpoles lose their tail regenerative ability. Within 10 h after tail amputation, xNP1 was induced at the amputation site regardless of the tail regenerative ability, suggesting that xNP1 functions in acute phase responses. xNP1 was widely expressed in regenerating tails, but not in the tail buds of tailbud embryos, suggesting its possible role in the immune response/healing after an injury. xNP1 expression was also observed in neural tissues/primordia in tailbud embryos and in the spinal cord in regenerating/healing tails in both periods, implying its possible roles in neural development or function. Moreover, during the first 48 h after amputation, xNP1 expression was sustained at the spinal cord of tails in the 'regeneration' period tadpoles, but not in the 'refractory' period tadpoles, suggesting that xNP1 expression at the spinal cord correlates with regeneration. Our findings suggest that xNP1 is involved in both acute phase responses and neural development/functions, which is unique compared to mammalian pentraxins whose family members are specialized in either acute phase responses or neural functions.

Pentraxin-3 levels in graft-versus-host disease during allogeneic hematopoietic stem cell transplantation

Acute and chronic graft-versus-host-diseases (aGVHD and cGVHD, respectively) are serious complications after hematopoietic stem cell transplantation (HSCT), impairing survival and quality of life. Because the underlying pathomechanism of GVHD is still poorly understood, we investigated the novel inflammatory marker Pentraxin-3 (PTX3) for its potential role in acute and chronic GVHD compared with autologous HSCT and healthy individuals. We collected plasma samples from patients undergoing autologous (n = 12) and allogeneic (n = 28) HSCT and from healthy individuals (n = 15) throughout 7 days before and up to 1 year after HSCT. PTX3 levels in patients with aGVHD were significantly higher (36.4 ± 23.6 ng/mL) than in allogeneic patients without aGVHD (10.4 ± 4.4 ng/mL, p = 0.0001), autologous controls (11.4 ± 6.7 ng/mL, p = 0.001), or healthy individuals (1.9 ± 0.6 ng/mL, p < 0.001). PTX3 levels in patients with cGVHD (13.6 ± 6.3 ng/mL) were significantly lower than in allogeneic patients without cGVHD (25.1 ± 13.8 ng/mL, p = 0.04) and higher than in autologous controls (8.9 ± 7.8 ng/mL, p = 0.07) and healthy individuals (1.9 ± 0.6 ng/mL, p < 0.001). Severity of aGVHD and cGVHD correlated with PTX3 levels. Rising PTX3 levels after HSCT indicated unfavorable outcome. We show that PTX3 levels correlate with the severity of aGVHD, cGVHD, and-with reservations-survival in patients undergoing allogeneic HSCT.

Pentraxin 3: an immune modulator of infection and useful marker for disease severity assessment in sepsis

The acute phase protein pentraxin 3 (PTX3) is a pattern recognition receptor involved in regulation of the host immune response. This relatively newly discovered member of the pentraxin superfamily elicits both immunostimulatory and immunoregulatory functions preventing autoimmune pathology and orchestrated clearance of pathogens through opsonization of damage- and pathogen-associated molecular patterns (DAMP/PAMP). Thus, PTX3 has been described as a possible evolutionary precursor to immunoglobulins. While shown to provide protection against specific bacterial and fungal pathogens, persistent elevation of PTX3 levels following initial onset of infection appear to predict poor patient outcome and may contribute to disease sequelae such as tissue damage and coagulopathy. Measurement of PTX3 following onset of sepsis may improve patient risk assessment and thus be useful in guiding subsequent therapeutic interventions including steroidal anti-inflammatory and altered antibiotic therapies. In this review, we summarize the role of PTX3 in inflammatory syndromes and its utility as a marker of sepsis disease severity.

Pentraxin-3 regulates the inflammatory activity of macrophages

Background and aims

Pentraxin-3 (PTX3) reportedly has protective roles in atherosclerosis and myocardial infarction, and is a useful biomarker of vascular inflammation. However, the detailed functions of PTX3 in inflammation are yet to be elucidated. This study aimed to investigate the function of PTX3 in macrophages.

Methods

PMA-treated THP-1 cell line (THP-1 macrophage) and monocyte-derived human primary macrophages were treated with recombinant PTX3. Cytokine and chemokine levels in the THP-1 culture medium were measured as well as monocyte chemoattractant protein (MCP-1) concentrations in the Raw 264.7 cell culture medium. PTX3-silenced apoptotic macrophages (THP-1 cell line) were generated to investigate the roles of PTX3 in phagocytosis.

Results

In the presence of PTX3, macrophage interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and MCP-1 levels were reduced significantly (−39%, P=0.007; −21%, P=0.008; and −67%, P=0.0003, respectively), whilst activated transforming growth factor-β (TGF−β) was detected in the THP-1 macrophages (P=0.0004). Additionally, PTX3 induced Akt phosphorylation and reduced nuclear factor-kappa B (NF-κB) activation by 35% (P=0.002), which was induced by TNF-α in THP-1 macrophages. Furthermore, silencing of PTX3 in apoptotic cells resulted in increased macrophage binding, elevated expression rate of HLA-DR (+30%, P=0.015) and CD86 (+204%, P=0.004) positive cells, and induction of IL-1β (+36%, P=0.024) production. Conversely, adding recombinant PTX3 to macrophages reduced CD86 and HLA-DR expression in a dose-dependent manner.

Conclusions

We identified PTX3 as a novel regulator of macrophage activity, and this function suggests that PTX3 acts to resolve inflammation.

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PTX3 reduces pro-inflammatory cytokines from macrophages and induced active TGFβ.

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PTX3 upregulates Akt phosphorylation in macrophages.

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PTX3 reduces TNFα induced NFκ-B activation.

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Silencing PTX3 of apoptotic cells evokes phagocytic activity of macrophages.

Human umbilical cord blood-derived mesenchymal stem cells improve functional recovery through thrombospondin1, pantraxin3, and vascular endothelial growth factor in the ischemic rat brain

Cell therapy is a potential therapeutic method for cerebral ischemia, which remains a serious problem. In the search for more effective therapeutic methods, many kinds of stem cells from various tissues have been developed and tested as candidate therapeutic agents. Among them, human umbilical cord blood (hUCB)-derived mesenchymal stem cells (MSCs) are widely used for cell therapy because of their genetic flexibility. To confirm that they are effective and understand how they affect ischemic neural cells, hUCB-MSCs were directly administered ipsilaterally into an ischemic zone induced by middle cerebral artery occlusion (MCAO). We found that the neurobehavioral performance of the hUCB-MSC group was significantly improved compared with that of the vehicle-injected control group. The infarct was also remarkably smaller in the hUCB-MSC group. Additionally, hUCB-MSC transplantation resulted in a greater number of newly generated cells and angiogenic and tissue repair factors and a lower number of inflammatory events in the penumbra zone. To determine why these events occurred, hUCB-MSCs were assayed under hypoxic and normoxic conditions in vitro. The results showed that hUCB-MSCs exhibit higher expression levels of thrombospondin1, pantraxin3, and vascular endothelial growth factor under hypoxic conditions than under normoxic conditions. These results were found to be correlated with our in vivo immunofluorescent staining results. On the basis of these findings, we suggest that hUCB-MSCs may have a beneficial effect on cerebral ischemia, especially through angiogenesis, neurogenesis, and anti-inflammatory effects, and thus could be used as a therapeutic agent to treat neurological disorders such as cerebral ischemia.

Lipopolysaccharide challenge induces long pentraxin 3 expression in mice independently from acute lung injury

OBJECTIVE

To determine whether the onset of acute lung injury (ALI) induces the up-regulation of pentraxin 3 (PTX3) expression in mice and whether PTX3 concentration in the biofluid can help recognizing sepsis-induced ALI.

METHODS

Wild-type C57BL/6 mice (12-14 weeks old) were randomly divided into 3 groups. Mice in the group 1 (n=12) and group 2 (n=12) were instilled with lipopolysaccharide via intratracheal or intraperitoneal routes, respectively. Mice in the group 3 (n=8) were taken as blank controls. Pulmonary morphological and functional alterations were measured to determine the presence of experimental ALI. PTX3 expression in the lung was quantified at both protein and mRNA levels. PTX3 protein concentration in blood and bronchoalveolar lavage fluid was measured to evaluate its ability to diagnose sepsis-induced ALI by computing area under receiver operator characteristic curve (AUROCC).

RESULTS

ALI was commonly confirmed in the group 1 but never in the other groups. PTX3 expression was up-regulated indiscriminately among lipopolysaccharide-challenged mice. PTX3 protein concentration in the biofluid was unable to diagnose sepsis-induced ALI evidenced by its small AUROCC. PTX3 concentration in bronchoalveolar lavage fluid did not correlate with that in serum.

CONCLUSIONS

Lipopolysaccharide challenges induced PTX3 expression in mice regardless of the presence of ALI. PTX3 may act as an indicator of inflammatory response instead of organ injury per se.

Pentraxin 3 is reduced in bipolar disorder

OBJECTIVE

Immunologic abnormalities have been found in bipolar disorder but pentraxin 3, a marker of innate immunity, has not been studied in this population.

METHODS

Levels of pentraxin 3 were measured in individuals with bipolar disorder, schizophrenia, and non-psychiatric controls. Linear regression models were used to compare the pentraxin 3 levels in each of the psychiatric groups to that in the control group, adjusting for demographic and clinical variables. Logistic regression models were used to calculate the odds ratios associated with levels of pentraxin 3 which differed from specified levels of the control group.

RESULTS

The sample consisted of 831 individuals: 256 with bipolar disorder, 309 with schizophrenia, and 266 without a psychiatric disorder. The levels of pentraxin 3 in the bipolar disorder, but not in the schizophrenia, group were significantly lower than those of controls, adjusting for age, gender, race, maternal education, smoking status, and body mass index (t = -3.78, p < 0.001). The individuals with bipolar disorder also had significantly increased odds of having low levels of pentraxin 3 relative to both the 10th and 25th percentile level of the controls and significantly decreased odds of having a level greater than the 75th and the 90th percentile level of the controls, adjusting for the same covariates.

CONCLUSIONS

Individuals with bipolar disorder have low levels of pentraxin 3 which may reflect impaired innate immunity. An increased understanding of the role of innate immunity in the etiopathogenesis of bipolar disorder might lead to new modalities for the diagnosis and treatment of this disorder.

Whole Tumor Antigen Vaccines: Where Are We?

With its vast amount of uncharacterized and characterized T cell epitopes available for activating CD4⁺ T helper and CD8⁺ cytotoxic lymphocytes simultaneously, whole tumor antigen represents an attractive alternative source of antigens as compared to tumor-derived peptides and full-length recombinant tumor proteins for dendritic cell (DC)-based immunotherapy. Unlike defined tumor-derived peptides and proteins, whole tumor lysate therapy is applicable to all patients regardless of their HLA type. DCs are essentially the master regulators of immune response, and are the most potent antigen-presenting cell population for priming and activating naïve T cells to target tumors. Because of these unique properties, numerous DC-based immunotherapies have been initiated in the clinics. In this review, we describe the different types of whole tumor antigens that we could use to pulse DCs ex vivo and in vivo. We also discuss the different routes of delivering whole tumor antigens to DCs in vivo and activating them with toll-like receptor agonists.

Pentraxin 3: a novel biomarker for predicting progression from prostatic inflammation to prostate cancer

Pentraxin-3 (PTX3) is a member of the pentraxin family of innate immune regulators, which includes C-reactive protein (CRP). PTX3 has been implicated in angiogenesis, proliferation, and immune escape in cancer. In the present study, we evaluated PTX3 tissue expression and serum concentration as a biomarker to discriminate prostatic inflammation and benign prostatic hyperplasia (BPH) from prostate cancer, and to determine whether PTX3 status may predict progression from BPH to prostate cancer. We analyzed 40 patients with biopsy-proven BPH who underwent a second prostate biopsy 12 to 36 months later when they were diagnosed with prostate cancer or inflammation/BPH (n = 20 patients each group). Furthermore, we evaluated PTX3 serum concentrations in an independent set of patients with biopsy-proven inflammation/BPH (n = 61) and prostate cancer (n = 56). We found reduced PTX3 tissue expression in patients with prostatic inflammation/BPH compared with patients who developed prostate cancer. In the latter group, there was an increase in PTX3 tissue expression between the first and second prostate biopsy. PTX3 serum levels were also higher in patients with prostate cancer than in patients with inflammation/BPH. In contrast, there was no difference in serum PSA or CRP levels in these two groups. ROC curve analysis confirmed the reliability of PTX3 serum levels in predicting prostate cancer development, identifying a cutoff value of 3.25 ng/mL with a sensitivity and a specificity of 89.3% and 88.5%, respectively. In summary, our results encourage further evaluation of PTX3 as a tissue biopsy and blood-borne biomarker to discriminate BPH from prostate cancer.

Intravascular immunity as a key to systemic vasculitis: a work in progress, gaining momentum

Vascular inflammation contributes to the defence against invading microbes and to the repair of injured tissues. In most cases it resolves before becoming apparent. Vasculitis comprises heterogeneous clinical entities that are characterized by the persistence of vascular inflammation after it has served its homeostatic function. Most underlying mechanisms have so far remained elusive. Intravascular immunity refers to the surveillance of the vasculature by leucocytes that sense microbial or sterile threats to vessel integrity and initiate protective responses that entail most events that determine the clinical manifestations of vasculitis, such as end-organ ischaemia, neutrophil extracellular traps generation and thrombosis, leucocyte extravasation and degranulation. Understanding how the resolution of vascular inflammation goes awry in patients with systemic vasculitis will facilitate the identification of novel pharmacological targets and bring us a step closer in each patient to the selection of more effective and less toxic treatments.

Citrullination of autoantigens implicates NETosis in the induction of autoimmunity

Tolerance blocks the expression of autoantibodies, whereas autoimmunity promotes it. How tolerance breaks and autoantibody production begins thus are crucial questions for understanding and treatment of autoimmune diseases. Evidence implicates cell death and autoantigen modifications in the initiation of autoimmune reactions. One form of neutrophil cell death called NETosis deserves attention because it requires the post-translational modification of histones and results in the extracellular release of chromatin. NETosis received its name from NET, the acronym given to Neutrophil Extracellular Trap. The extracellular chromatin incorporates histones in which arginines have been converted to citrullines by peptidylarginine deiminase IV (PAD4). The deiminated chromatin may function to capture or 'trap' bacterial pathogens, thus generating an extracellular complex of deiminated histones and bacterial cell adjuvants. The complex of bacterial antigens and deiminated chromatin may be internalised by host phagocytes during acute inflammatory conditions, as arise during bacterial infections or chronic autoinflammatory disorders. The uptake and processing of deiminated chromatin together with bacterial adjuvants by phagocytes may induce the presentation of modified histone epitopes and co-stimulation, thus yielding a powerful stimulus to break tolerance. Autoantibodies to deiminated histones are prevalent in Felty's syndrome patients and are present in systemic lupus erythematosus (SLE) and patients with rheumatoid arthritis (RA). These observations clearly implicate histone deimination as an epigenetic mark that can act as an autoantibody stimulant.

Functional and molecular characterization of ex vivo cultured epiretinal membrane cells from human proliferative diabetic retinopathy

Characterization of the cell surface marker phenotype of ex vivo cultured cells growing out of human fibrovascular epiretinal membranes (fvERMs) from proliferative diabetic retinopathy (PDR) can give insight into their function in immunity, angiogenesis, and retinal detachment. FvERMs from uneventful vitrectomies due to PDR were cultured adherently ex vivo. Surface marker analysis, release of immunity- and angiogenesis-pathway-related factors upon TNF α activation and measurement of the intracellular calcium dynamics upon mechano-stimulation using fluorescent dye Fura-2 were all performed. FvERMs formed proliferating cell monolayers when cultured ex vivo, which were negative for endothelial cell markers (CD31, VEGFR2), partially positive for hematopoietic- (CD34, CD47) and mesenchymal stem cell markers (CD73, CD90/Thy-1, and PDGFR β ), and negative for CD105. CD146/MCAM and CD166/ALCAM, previously unreported in cells from fvERMs, were also expressed. Secretion of 11 angiogenesis-related factors (DPPIV/CD26, EG-VEGF/PK1, ET-1, IGFBP-2 and 3, IL-8/CXCL8, MCP-1/CCL2, MMP-9, PTX3/TSG-14, Serpin E1/PAI-1, Serpin F1/PEDF, TIMP-1, and TSP-1) were detected upon TNF α activation of fvERM cells. Mechano-stimulation of these cells induced intracellular calcium propagation representing functional viability and role of these cells in tractional retinal detachment, thus serving as a model for studying tractional forces present in fvERMs in PDR ex vivo.

Blood monocyte chemotactic protein-1 (MCP-1) and adapted disease activity Score28-MCP-1: favorable indicators for rheumatoid arthritis activity

OBJECTIVE

We assessed blood pentraxin 3 (PTX3) and macrophage chemotactic factor-1 (MCP-1) levels as indicators of disease activity in rheumatoid arthritis (RA) patients, because data on disease activity score 28 (DAS28)-erythrocyte sedimentation rate (ESR) and DAS28-C-reactive protein (CRP) are still imperfect.

METHODS

In 111 patients with RA, we examined longitudinal and cross-sectional correlations of blood PTX3, MCP-1, CRP, and ESR levels with measures of clinical arthritic activity, namely, swollen joint count (SJC), tender joint count (TJC), visual analog scale for general health (GH), DAS28, and adapted DAS28-MCP-1.

RESULTS

Blood MCP-1, but not PTX3, was significantly correlated with SJC, TJC, DAS28, and DAS28-CRP. DAS28-MCP-1 was strongly correlated with DAS28 (r  = 0.984, P<0.001) and DAS28-CRP (r  = 0.971, P<0.001), and modestly correlated with CRP (r  = 0.350, P<0.001), and ESR (r  = 0.386, P<0.001). Similarly, the duration of arthritic symptoms, but not sex, was significantly correlated with variables of arthritic activity. In particular, DAS28-MCP-1 significantly correlated with DAS28 during a 6-month period (r  = 0.944, P<0.001; r  = 0.951, P<0.001; r  = 0.862, P<0.001; and r  = 0.865, P<0.001 for month 0, 1, 3, and 6, respectively).

CONCLUSION

Blood MCP-1 and adapted DAS28-MCP-1, but not blood PTX3, may be useful in monitoring RA activity.

Pentraxin 3(PTX 3): an endogenous modulator of the inflammatory response

Inflammatory or anti-inflammatory? That is the question as far as the acute-phase response and its mediators, the pentraxins, are concerned. Only some ten years ago, the classical or short pentraxin C-reactive protein and the newly discovered long pentraxin PTX3 were considered to exert most of the detrimental effects of acute inflammation, whether microbial or sterile in origin. However, accumulating evidence suggests an at least dichotomous, context-dependent outcome attributable to the pentraxins, if not a straightforward anti-inflammatory nature of the acute-phase response. This paper is focused on the inherent effects of pentraxin 3 in inflammatory responses, mainly in coronary artery disease and in Aspergillus fumigatus infection. Both are examples of inflammatory reactions in which PTX3 is substantially involved; the former sterile, the latter infectious in origin. Apart from different inducing noxae, similarities in the pathogenesis of the two are striking. All the same, the introductory question still persists: is the ultimate impact of PTX3 in these conditions inflammatory or anti-inflammatory, paradoxical as the latter might appear? We try to provide an answer such as it emerges in the light of recent findings.

The role of humoral innate immunity in hepatitis C virus infection

Infection with Hepatitis C Virus (HCV) causes chronic disease in approximately 80% of cases, resulting in chronic inflammation and cirrhosis. Current treatments are not completely effective, and a vaccine has yet to be developed. Spontaneous resolution of infection is associated with effective host adaptive immunity to HCV, including production of both HCV-specific T cells and neutralizing antibodies. However, the supporting role of soluble innate factors in protection against HCV is less well understood. The innate immune system provides an immediate line of defense against infections, triggering inflammation and playing a critical role in activating adaptive immunity. Innate immunity comprises both cellular and humoral components, the humoral arm consisting of pattern recognition molecules such as complement C1q, collectins and ficolins. These molecules activate the complement cascade, neutralize pathogens, and recruit antigen presenting cells. Here we review the current understanding of anti-viral components of the humoral innate immune system that play a similar role to antibodies, describing their role in immunity to HCV and their potential contribution to HCV pathogenesis.

Pentraxins in humoral innate immunity

Innate immunity represents the first line of defence against pathogens and plays key roles in activation and orientation of the adaptive immune response. The innate immune system comprises both a cellular and a humoral arm. Components of the humoral arm include soluble pattern recognition molecules (PRMs) that recognise pathogens associated molecular patterns (PAMPs) and initiate the immune response in coordination with the cellular arm, therefore acting as functional ancestors of antibodies. The long pentraxin PTX3 is a prototypic soluble PRM that is produced at sites of infection and inflammation by both somatic and immune cells. Gene targeting of this evolutionarily conserved protein has revealed a non-redundant role in resistance to selected pathogens. Moreover, PTX3 exerts important functions at the crossroad between innate immunity, inflammation and female fertility. Here we review the studies on PTX3, with emphasis on pathogen recognition and crosstalk with other components of the innate immune system.

Long pentraxin 3 (PTX3) in the light of its structure, mechanism of action and clinical implications

Pentraxins are a group of evolutionarily conserved ancient proteins. Depending on their structure, pentraxins are divided into short and long pentraxin families. Pentraxin 3 (PTX3) is the prototype of the long pentraxin group. PTX3 synthesis is stimulated by a variety of molecules involved in the inflammatory process. The inflammatory mediator is typically produced at inflammatory sites; however, it can also be released at the sites remote from the original inflammatory insult. Although mainly expressed by vascular endothelium and smooth muscle cells, PTX3 is also synthesized by myeloid dendritic cells, mononuclear macrophages/phagocytes, vascular endothelial and smooth muscle cells, fibroblasts, adipocytes, cumulus oophorus cells mesangial cells, synovial cells and chondrocytes. PTX3 binds to several ligands including complement component C1q, factor H, ficolin-1 (M-ficolin), mannose-binding lectin, fibroblast growth factor 2, P-selectin, matrix protein TSG6 and Klebsiella pneumoniae; it is also known to play a role in humoral innate immunity as well as in degenerated and apoptotic cells clearance. PTX3 acts as a modulator of inflammatory processes, modifies angiogenesis and atherosclerotic lesion development, and participates in extracellular matrix formation. Due to the fact of PTX3 being primarily produced and released by vascular wall cells, it might be used as a sensitive and independent inflammatory marker.

Adjuvants for enhancing the immunogenicity of whole tumor cell vaccines

Whole tumor cell lysates can serve as excellent multivalent vaccines for priming tumor-specific CD8(+) and CD4(+) T cells. Whole cell vaccines can be prepared with hypochlorous acid oxidation, UVB-irradiation and repeat cycles of freeze and thaw. One major obstacle to successful immunotherapy is breaking self-tolerance to tumor antigens. Clinically approved adjuvants, including Montanide™ ISA-51 and 720, and keyhole-limpet proteins can be used to enhance tumor cell immunogenicity by stimulating both humoral and cellular anti-tumor responses. Other potential adjuvants, such as Toll-like receptor agonists (e.g., CpG, MPLA and PolyI:C), and cytokines (e.g., granulocyte-macrophage colony stimulating factor), have also been investigated.

Pathogen recognition by the long pentraxin PTX3

Innate immunity represents the first line of defence against pathogens and plays key roles in activation and orientation of the adaptive immune response. The innate immune system comprises both a cellular and a humoral arm. Components of the humoral arm include soluble pattern recognition molecules (PRMs) that recognise pathogen-associated molecular patterns (PAMPs) and initiate the immune response in coordination with the cellular arm, therefore acting as functional ancestors of antibodies. The long pentraxin PTX3 is a prototypic soluble PRM that is produced at sites of infection and inflammation by both somatic and immune cells. Gene targeting of this evolutionarily conserved protein has revealed a nonredundant role in resistance to selected pathogens. Moreover, PTX3 exerts important functions at the cross-road between innate immunity, inflammation, and female fertility. Here, we review the studies on PTX3, with emphasis on pathogen recognition and cross-talk with other components of the innate immune system.

CCAAT/enhancer binding protein delta (CEBPD) elevating PTX3 expression inhibits macrophage-mediated phagocytosis of dying neuron cells

The CCAAT/enhancer binding protein delta (CEBPD, C/EBPδ, NF-IL6β) is induced in many inflammation-related diseases, suggesting that CEBPD and its downstream targets may play central roles in these conditions. Neuropathological studies show that a neuroinflammatory response parallels the early stages of Alzheimer's disease (AD). However, the precise mechanistic correlation between inflammation and AD pathogenesis remains unclear. CEBPD is upregulated in the astrocytes of AD patients. Therefore, we asked if activation of astrocytic CEBPD could contribute to AD pathogenesis. In this report, a novel role of CEBPD in attenuating macrophage-mediated phagocytosis of damaged neuron cells was found. By global gene expression profiling, we identified the inflammatory marker pentraxin-3 (PTX3, TNFAIP5, TSG-14) as a CEBPD target in astrocytes. Furthermore, we demonstrate that PTX3 participates in the attenuation of macrophage-mediated phagocytosis of damaged neuron cells. This study provides the first demonstration of a role for astrocytic CEBPD and the CEBPD-regulated molecule PTX3 in the accumulation of damaged neurons, which is a hallmark of AD pathogenesis.

Pentraxins in innate immunity: lessons from PTX3

The innate immune system constitutes the first line of defence against microorganisms and plays a primordial role in the activation and regulation of adaptive immunity. The innate immune system is composed of a cellular arm and a humoral arm. Components of the humoral arm include members of the complement cascade and soluble pattern recognition molecules (PRMs). These fluid-phase PRMs represent the functional ancestors of antibodies and play a crucial role in the discrimination between self, non-self and modified-self. Moreover, evidence has been presented that these soluble PRMs participate in the regulation of inflammatory responses and interact with the cellular arm of the innate immune system. Pentraxins consist of a set of multimeric soluble proteins and represent the prototypic components of humoral innate immunity. Based on the primary structure of the protomer, pentraxins are divided into two groups: short pentraxins and long pentraxins. The short pentraxins C-reactive protein and serum amyloid P-component are produced by the liver and represent the main acute phase proteins in human and mouse, respectively. The long pentraxin PTX3 is produced by innate immunity cells (e.g. PMN, macrophages, dendritic cells), interacts with several ligands and plays an essential role in innate immunity, tuning inflammation and matrix deposition. PTX3 provides a paradigm for the mode of action of humoral innate immunity.

PTX3 expression in the heart tissues of patients with myocardial infarction and infectious myocarditis

INTRODUCTION

The long pentraxin 3 is involved in innate resistance to pathogens, controlling inflammation and extracellular matrix remodeling. Moreover, pentraxin 3 plays a nonredundant role in the regulation of cardiac tissue damage in mice and, recently, it has been proposed as a new candidate marker for acute and chronic heart diseases. However, the actual localization and cellular sources of pentraxin 3 in ischemic and infectious cardiac pathology have not been carefully defined.

METHODS

In this study, using immunohistochemistry, we analyzed pentraxin 3 expression in the heart tissues of patients with acute myocardial infarction at different time points after the ischemic event. In addition, we studied the heart tissues of patients with infectious myocarditis (fungi, bacteria, and protozoa) and patients who died of noncardiac events with normal heart histology.

RESULTS

In acute myocardial infarction cases, we observed pentraxin 3 localized within and around ischemic lesions. On the contrary, no pentraxin 3 was observed in normal heart areas. In early ischemic lesions, pentraxin 3 was localized primarily in granulocytes; in more advanced acute myocardial infarction, pentraxin 3 positivity was found in the interstitium and in the cytoplasm of macrophages and the endothelium, whereas most granulocytes did not express pentraxin 3, presumably as a consequence of degranulation. In infectious myocarditis, pentraxin 3 was present and localized within and around histological lesions, associated with macrophage, endothelial cell, and, more rarely, myocardiocyte and granulocyte positivities. As observed in acute myocardial infarction patients, no pentraxin 3 staining was found in normal heart areas.

CONCLUSIONS

Thus, neutrophils are an early source of pentraxin 3 in acute myocardial infarction and presumably other inflammatory heart disorders. Subsequently, in acute myocardial infarction and infectious myocarditis, pentraxin 3 is produced by macrophages, the endothelium, and, to a lesser extent, myocardiocytes, and localized in the interstitium.

Whole tumor antigen vaccines

Although cancer vaccines with defined antigens are commonly used, the use of whole tumor cell preparations in tumor immunotherapy is a very promising approach and can obviate some important limitations in vaccine development. Whole tumor cells are a good source of TAAs and can induce simultaneous CTLs and CD4(+) T helper cell activation. We review current approaches to prepare whole tumor cell vaccines, including traditional methods of freeze-thaw lysates, tumor cells treated with ultraviolet irradiation, and RNA electroporation, along with more recent methods to increase tumor cell immunogenicity with HOCl oxidation or infection with replication-incompetent herpes simplex virus.

Maternal plasma pentraxin 3 at 11 to 13 weeks of gestation in hypertensive disorders of pregnancy

OBJECTIVE

To investigate whether in pregnancies that subsequently develop preeclampsia (PE), the maternal plasma concentration of the inflammatory factor pentraxin 3 (PTX3) at 11-13 weeks of gestation is increased and whether such a possible increase is associated with uterine artery pulsatility index (PI).

METHODS

The concentration of plasma PTX3 at 11-13 weeks was measured in a case-control study from 120 pregnancies that developed PE, including 27 who required delivery before 34 weeks (early PE), 87 cases of gestational hypertension (GH) and 207 normal controls. The median PTX3 multiple of the median (MoM) in the control and hypertensive groups were compared. Regression analysis was used to determine the significance of the association between plasma PTX3 and uterine artery PI.

RESULTS

Plasma PTX3 was significantly higher in the early PE group (1.44 MoM; p < 0.0083) but not in late PE (1.11 MoM) or GH (1.10 MoM) compared to the controls (0.97 MoM). There was no significant association between plasma PTX3 levels and uterine artery PI in either the PE group (p = 0.693) or in the controls (p = 0.209).

CONCLUSION

Increase in maternal plasma PTX3 in pregnancies that subsequently develop early PE is evident from 11-13 weeks but the underlying mechanism for such an increase remains uncertain.

Molecular mechanisms of late apoptotic/necrotic cell clearance

Phagocytosis serves as one of the key processes involved in development, maintenance of tissue homeostasis, as well as in eliminating pathogens from an organism. Under normal physiological conditions, dying cells (e.g., apoptotic and necrotic cells) and pathogens (e.g., bacteria and fungi) are rapidly detected and removed by professional phagocytes such as macrophages and dendritic cells (DCs). In most cases, specific receptors and opsonins are used by phagocytes to recognize and bind their target cells, which can trigger the intracellular signalling events required for phagocytosis. Depending on the type of target cell, phagocytes may also release both immunomodulatory molecules and growth factors to orchestrate a subsequent immune response and wound healing process. In recent years, evidence is growing that opsonins and receptors involved in the removal of pathogens can also aid the disposal of dying cells at all stages of cell death, in particular plasma membrane-damaged cells such as late apoptotic and necrotic cells. This review provides an overview of the molecular mechanisms and the immunological outcomes of late apoptotic/necrotic cell removal and highlights the striking similarities between late apoptotic/necrotic cell and pathogen clearance.