Vascular pentraxin 3 controls arterial thrombosis by targeting collagen and fibrinogen induced platelets aggregation

Association between blood Pentraxin-3 concentrations and rheumatic diseases: A systematic review and meta-analysis

BACKGROUND

Among the Pentraxins, the long Pentraxin-3 (PTX-3) is associated with several processes, particularly in the earliest phases of the innate humoral response. Increased blood PTX-3 concentrations have been observed in a wide range of conditions, from infectious to cardiovascular disorders. Since its increase is more rapid than C-reactive protein (CRP), PTX-3 can be useful to detect and monitor early inflammation. To dissect its pathophysiological role in rheumatic diseases (RD), we conducted a systematic review and meta-analysis comparing blood PTX-3 concentrations in RD patients and healthy individuals and investigating possible associations with clinical, demographic, and study characteristics.

METHODS

We performed a search of published evidence until April 2024 in PubMed, Web of Science and Scopus, which led to the selection of 60 relevant manuscripts from a total of 1072 records.

RESULTS

Our synthesis revealed a statistically significant difference in PTX-3 concentrations between RD patients and controls (standard mean difference, SMD = 1.02, 95% CI 0.77-1.26, p < .001), that correlated with CRP concentrations. The effect size was associated with geographical region of study conduction, RD type, with a reduction of the observed heterogeneity in patients with low LDL-cholesterol and triglycerides concentrations.

CONCLUSIONS

Our study has shown a significant increase in blood PTX-3 concentrations in RD patients, which was associated with specific patient characteristics. Nevertheless, additional studies are needed to better define the utility of measuring PTX-3 in the early phase of RD. Our study was conducted in compliance with the PRISMA 2020 statement (study protocol available at PROSPERO CRD42024516600).

Meta-analysis of the correlation between pulmonary hypertension and echocardiographic parameters in patients with chronic kidney disease

Objective

To investigate the correlation between pulmonary hypertension (PH) and echocardiographic parameters in patients with chronic kidney disease (CKD).

Methods

PubMed, Embase, Web of Science, Cochrane, VIP, CNKI, and Wanfang databases were systematically searched for articles published from inception to 19 May 2023. Study quality was estimated using the Quality Assessment of Case-Control Studies tool. Forest plots were drawn using R language software. The "metacor" function in the "meta" package was utilized for meta-analysis of the r-values and their standard errors. Heterogeneity and sensitivity analyses were carried out, with the main outcomes as r-value, p-value, and I2 value.

Results

Eleven studies were included, with 1,809 CKD patients. The correlations between 12 echocardiographic parameters and PH were analyzed. Except for FS and LVEF which were negatively correlated with CKD-PH, the other 10 parameters were positively correlated with CKD-PH. Among them, LA was highly correlated with CKD-PH (0.70 < r < 0.89); LVDD, RA, RV, LVMI, and LVDS were moderately correlated with CKD-PH (0.40 < r < 0.69); while PA, IVS, LVPW, SV, FS, and LVEF were lowly correlated with CKD-PH (0.20 < r < 0.39). The synthesized estimates were stable against heterogeneity.

Conclusion

CKD-PH patients may have large cardiac chambers, thickened septal tissue on both sides of the chambers, reduced pulmonary artery flow rates, and decreased left ventricular function.

Evaluating the Expression of Candidate Homeobox Genes and Their Role in Local-Site Inflammation in Mucosal Tissue Obtained from Children with Non-Syndromic Cleft Lip and Palate

Craniofacial development including palatogenesis is a complex process which requires an orchestrated and spatiotemporal expression of various genes and factors for proper embryogenesis and organogenesis. One such group of genes essential for craniofacial development is the homeobox genes, transcriptional factors that are commonly associated with congenital abnormalities. Amongst these genes, DLX4, HOXB3, and MSX2 have been recently shown to be involved in the etiology of non-syndromic cleft lip and palate. Hence, we investigated the gene and protein expression of these genes in normal and cleft affected mucosal tissue obtained from 22 children, along with analyzing their role in promoting local-site inflammation using NF-κB. Additionally, we investigated the role of PTX3, which plays a critical role in tissue remodeling and wound repair. We found a residual gene and protein expression of DLX4 in cleft mucosa, although no differences in gene expression levels of HOXB3 and MSX2 were noted. However, a significant increase in protein expression for these genes was noted in the cleft mucosa (p < 0.05), indicating increased cellular proliferation. This was coupled with a significant increase in NF-κB protein expression in cleft mucosa (p < 0.05), highlighting the role of these genes in promotion of pro-inflammatory environment. Finally, no differences in gene expression of PTX3 were noted.

Platelet Function in CKD: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with CKD are at high risk for thrombotic and hemorrhagic complications. Abnormalities in platelet function are central to these complications, but reports on platelet function in relation to CKD are conflicting, and vary from decreased platelet reactivity to normal or increased platelet responsiveness. The direct effects of uremic toxins on platelet function have been described, with variable findings.

METHODS

To help clarify how CKD affects platelet function, we conducted a systematic review and meta-analysis of platelet activity in CKD, with a focus on nondialysis-induced effects. We also performed an extensive literature search for the effects of individual uremic toxins on platelet function.

RESULTS

We included 73 studies in the systematic review to assess CKD's overall effect on platelet function in patients; 11 of them described CKD's effect on ex vivo platelet aggregation and were included in the meta-analysis. Although findings on platelet abnormalities in CKD are inconsistent, bleeding time was mostly prolonged and platelet adhesion mainly reduced. Also, the meta-analysis revealed maximal platelet aggregation was significantly reduced in patients with CKD upon collagen stimulation. We also found that relatively few uremic toxins have been examined for direct effects on platelets ex vivo; ex vivo analyses had varying methods and results, revealing both platelet-stimulatory and inhibitory effects. However, eight of the 12 uremic toxins tested in animal models mostly induced prothrombotic effects.

CONCLUSIONS

Overall, most studies report impaired function of platelets from patients with CKD. Still, a substantial number of studies find platelet function to be unchanged or even enhanced. Further investigation of platelet reactivity in CKD, especially during different CKD stages, is warranted.

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.

PTX3 Effects on Osteogenic Differentiation in Osteoporosis: An In Vitro Study

Pentraxin 3 (PTX3) is a glycoprotein belonging to the humoral arm of innate immunity that participates in the body’s defence mechanisms against infectious diseases. It has recently been defined as a multifunctional protein, given its involvement in numerous physiological and pathological processes, as well as in the pathogenesis of age-related diseases such as osteoporosis. Based on this evidence, the aim of our study was to investigate the possible role of PTX3 in both the osteoblastic differentiation and calcification process: to this end, primary osteoblast cultures from control and osteoporotic patients were incubated with human recombinant PTX3 (hrPTX3) for 72 h. Standard osteinduction treatment, consisting of β-glycerophosphate, dexamethasone and ascorbic acid, was used as control. Our results showed that treatment with hrPTX3, as well as with the osteogenic cocktail, induced cell differentiation towards the osteoblastic lineage. We also observed that the treatment not only promoted an increase in cell proliferation, but also the formation of calcification-like structures, especially in primary cultures from osteoporotic patients. In conclusion, the results reported here suggest the involvement of PTX3 in osteogenic differentiation, highlighting its osteoinductive capacity, like the standard osteoinduction treatment. Therefore, this study opens new and exciting perspectives about the possible role of PTX3 as biomarker and therapeutic agent for osteoporosis.

The Long Pentraxin PTX3 Controls Klebsiella Pneumoniae Severe Infection

Klebsiella pneumoniae is a common pathogen in human sepsis. The emergence of multidrug-resistant K. pneumoniae strains represents a major clinical challenge in nosocomial and community acquired infections. The long pentraxin PTX3, a key component of humoral innate immunity, is involved in resistance to selected pathogens by promoting opsonophagocytosis. We investigated the relevance of PTX3 in innate immunity against K. pneumoniae infections using Ptx3^-/- mice and mouse models of severe K. pneumoniae infections. Local and systemic PTX3 expression was induced following K. pneumoniae pulmonary infection, in association with the up-regulation of TNF-α and IL-1β. PTX3 deficiency in mice was associated with higher bacterial burden and mortality, release of pro-inflammatory cytokines as well as IL-10 in the lung and systemically. The analysis of the mechanisms responsible of PTX3-dependent control of K. pneumoniae infection revealed that PTX3 did not interact with K. pneumoniae, or promote opsonophagocytosis. The comparison of susceptibility of wild-type, Ptx3^-/-, C3^-/- and Ptx3^-/-/C3^-/- mice to the infection showed that PTX3 acted in a complement-independent manner. Lung histopathological analysis showed more severe lesions in Ptx3^-/- mice with fibrinosuppurative, necrotizing and haemorrhagic bronchopneumonia, associated with increased fibrin deposition in the lung and circulating fibrinogen consumption. These findings indicate that PTX3 contributes to the control of K. pneumoniae infection by modulating inflammatory responses and tissue damage. Thus, this study emphasizes the relevance of the role of PTX3 as regulator of inflammation and orchestrator of tissue repair in innate responses to infections.

Long pentraxin PTX3 is upregulated systemically and centrally after experimental neurotrauma, but its depletion leaves unaltered sensorimotor deficits or histopathology

Long pentraxin PTX3, a pattern recognition molecule involved in innate immune responses, is upregulated by pro-inflammatory stimuli, contributors to secondary damage in traumatic brain injury (TBI). We analyzed PTX3 involvement in mice subjected to controlled cortical impact, a clinically relevant TBI mouse model. We measured PTX3 mRNA and protein in the brain and its circulating levels at different time point post-injury, and assessed behavioral deficits and brain damage progression in PTX3 KO mice. PTX3 circulating levels significantly increased 1-3 weeks after injury. In the brain, PTX3 mRNA was upregulated in different brain areas starting from 24 h and up to 5 weeks post-injury. PTX3 protein significantly increased in the brain cortex up to 3 weeks post-injury. Immunohistochemical analysis showed that, 48 h after TBI, PTX3 was localized in proximity of neutrophils, likely on neutrophils extracellular traps (NETs), while 1- and 2- weeks post-injury PTX3 co-localized with fibrin deposits. Genetic depletion of PTX3 did not affect sensorimotor deficits up to 5 weeks post-injury. At this time-point lesion volume and neuronal count, axonal damage, collagen deposition, astrogliosis, microglia activation and phagocytosis were not different in KO compared to WT mice. Members of the long pentraxin family, neuronal pentraxin 1 (nPTX1) and pentraxin 4 (PTX4) were also over-expressed in the traumatized brain, but not neuronal pentraxin 2 (nPTX2) or short pentraxins C-reactive protein (CRP) and serum amyloid P-component (SAP). The long-lasting pattern of activation of PTX3 in brain and blood supports its specific involvement in TBI. The lack of a clear-cut phenotype in PTX3 KO mice may depend on the different roles of this protein, possibly involved in inflammation early after injury and in repair processes later on, suggesting distinct functions in acute phases versus sub-acute or chronic phases. Brain long pentraxins, such as PTX4-shown here to be overexpressed in the brain after TBI-may compensate for PTX3 absence.

HDL in Immune-Inflammatory Responses: Implications beyond Cardiovascular Diseases

High density lipoproteins (HDL) are heterogeneous particles composed by a vast array of proteins and lipids, mostly recognized for their cardiovascular (CV) protective effects. However, evidences from basic to clinical research have contributed to depict a role of HDL in the modulation of immune-inflammatory response thus paving the road to investigate their involvement in other diseases beyond those related to the CV system. HDL-C levels and HDL composition are indeed altered in patients with autoimmune diseases and usually associated to disease severity. At molecular levels, HDL have been shown to modulate the anti-inflammatory potential of endothelial cells and, by controlling the amount of cellular cholesterol, to interfere with the signaling through plasma membrane lipid rafts in immune cells. These findings, coupled to observations acquired from subjects carrying mutations in genes related to HDL system, have helped to elucidate the contribution of HDL beyond cholesterol efflux thus posing HDL-based therapies as a compelling interventional approach to limit the inflammatory burden of immune-inflammatory diseases.

The Role of PTX3 in Mineralization Processes and Aging-Related Bone Diseases

The Long Pentraxin 3 (PTX3) is a multifunctional glycoprotein released by peripheral blood leukocytes and myeloid dendritic cells in response to primary pro-inflammatory stimuli, that acts as a non-redundant component of the humoral arm of innate immunity. In addition to the primary role in the acute inflammatory response, PTX3 seems to be involved in other physiological and pathological processes. Indeed, PTX3 seems to play a pivotal role in the deposition and remodeling of bone matrix during the mineralization process, promoting osteoblasts differentiation and activity. Recently, PTX3 was seen to be involved in the ectopic calcifications' formation in breast cancer disease. In this regard, it has been observed that breast cancer tumors characterized by high expression of PTX3 and high amount of Breast Osteoblast Like Cells (BOLCs) showed several Hydroxyapatite (HA) microcalcifications, suggesting a likely role for PTX3 in differentiation and osteoblastic activity in both bone and extra-bone sites. Furthermore, given its involvement in bone metabolism, several studies agree with the definition of PTX3 as a molecule significantly involved in the pathogenesis of age-related bone diseases, such as osteoporosis, both in mice and humans. Recent results suggest that genetic and epigenetic mechanisms acting on PTX3 gene are also involved in the progression of these diseases. Based on these evidences, the aim of our systemic review was to offer an overview of the variety of biological processes in which PTX3 is involved, focusing on bone mineralization, both in a physiological and pathological context.

Rivaroxaban improves vascular response in LPS-induced acute inflammation in experimental models

Rivaroxaban (RVX) was suggested to possess anti-inflammatory and vascular tone modulatory effects. The goal of this study was to investigate whether RVX impacts lipopolysaccharide (LPS)-induced acute vascular inflammatory response. Male rats were treated with 5 mg/kg RVX (oral gavage) followed by 10 mg/kg LPS i.p injection. Circulating levels of IL-6, MCP-1, VCAM-1, and ICAM-1 were measured in plasma 6 and 24 hours after LPS injection, while isolated aorta was used for gene expression analysis, immunohistochemistry, and vascular tone evaluation. RVX pre-treatment significantly reduced LPS mediated increase after 6h and 24h for IL-6 (4.4±2.2 and 2.8±1.7 fold), MCP-1 (1.4±1.5 and 1.3±1.4 fold) VCAM-1 (1.8±2.0 and 1.7±2.1 fold). A similar trend was observed in the aorta for iNOS (5.5±3.3 and 3.3±1.9 folds reduction, P<0.01 and P<0.001, respectively), VCAM-1 (1.3±1.2 and 1.4±1.3 fold reduction, P<0.05), and MCP-1 (3.9±2.2 and 1.9±1.6 fold reduction, P<0.01). Moreover, RVX pre-treatment, improved LPS-induced PE contractile dysfunction in aortic rings (Control vs LPS, Emax reduction = 35.4 and 31.19%, P<0.001; Control vs LPS+RVX, Emax reduction = 10.83 and 11.48%, P>0.05, respectively), resulting in 24.5% and 19.7% change in maximal constriction in LPS and LPS+RVX respectively. These data indicate that RVX pre-treatment attenuates LPS-induced acute vascular inflammation and contractile dysfunction.

The Long Pentraxin PTX3 in Bone Homeostasis and Pathology

The innate immune system is equipped with a number of germ-line encoded soluble pattern recognition molecules (PRMs) that collectively mediate the humoral host response to infection and damage in cooperation with cells and tissues of the immune and non-immune compartments. Despite the impressive diversity in structure, source, and regulation across PRMs, these all share remarkably similar functions inasmuch as they recognize microbes and damaged tissues, activate complement, exert opsono-phagocytic activities, and regulate inflammation. The long pentraxin 3 (PTX3) is a prototypic soluble PRM. Long known as a major player in innate immunity, inflammation and matrix remodeling, only recently has PTX3 emerged as a mediator of bone homeostasis in rodents and humans. Ptx3-targeted mice exhibit reduced trabecular volume during bone development, and impaired callus mineralization following experimental fracture. The murine gene is expressed in vivo by non-hematopoietic periosteal cells in the early phases of fracture healing, and in vitro by maturing osteoblasts. Human osteoblasts do express the PTX3 protein, whose levels positively correlate with bone density in vivo and osteoblast proliferation and maturation in vitro, thus pointing to a role in bone deposition. Contrasting evidence, however, suggest osteoclastogenesis-promoting effects of PTX3, where its expression has been associated with periodontitis, arthritis, and bone metastasis, conditions hallmarked by inflammation and bone resorption. Here, we review past and recent literature on the functions exerted by this long pentraxin in bone biology, with major emphasis on physiological skeletal remodeling, fracture healing, and chronic diseases of the bone.

Pentraxin 3 in Cardiovascular Disease

The long pentraxin PTX3 is a member of the pentraxin family produced locally by stromal and myeloid cells in response to proinflammatory signals and microbial moieties. The prototype of the pentraxin family is C reactive protein (CRP), a widely-used biomarker in human pathologies with an inflammatory or infectious origin. Data so far describe PTX3 as a multifunctional protein acting as a functional ancestor of antibodies and playing a regulatory role in inflammation. Cardiovascular disease (CVD) is a leading cause of mortality worldwide, and inflammation is crucial in promoting it. Data from animal models indicate that PTX3 can have cardioprotective and atheroprotective roles regulating inflammation. PTX3 has been investigated in several clinical settings as possible biomarker of CVD. Data collected so far indicate that PTX3 plasma levels rise rapidly in acute myocardial infarction, heart failure and cardiac arrest, reflecting the extent of tissue damage and predicting the risk of mortality.

The Long Pentraxin PTX3 as a Link Between Innate Immunity, Tissue Remodeling, and Cancer

The innate immune system comprises a cellular and a humoral arm. Humoral pattern recognition molecules include complement components, collectins, ficolins, and pentraxins. These molecules are involved in innate immune responses by recognizing microbial moieties and damaged tissues, activating complement, exerting opsonic activity and facilitating phagocytosis, and regulating inflammation. The long pentraxin PTX3 is a prototypic humoral pattern recognition molecule that, in addition to providing defense against infectious agents, plays several functions in tissue repair and regulation of cancer-related inflammation. Characterization of the PTX3 molecular structure and biochemical properties, and insights into its interactome and multiple roles in tissue damage and remodeling support the view that microbial and matrix recognition are evolutionarily conserved functions of humoral innate immunity molecules.

Enhancement of Tissue Factor Expression in Monocyte-Derived Dendritic Cells by Pentraxin 3 and Its Modulation by C1 Esterase Inhibitor

BACKGROUND

We have previously shown that human monocyte-derived dendritic cells (moDCs) may participate in immune system-mediated hypercoagulable state through enhanced tissue factor (TF) expression and that the complement system may be involved in this process.

OBJECTIVES

The aim of this study was to explore the role of pentraxin 3 (PTX3) and the complement system in enhanced TF expression in moDCs.

METHODS

moDCs were generated from isolated human monocytes. PTX3 levels in whole human blood supplemented with moDCs were determined after lipopolysaccharide (LPS) stimulation. PTX3 release by the generated moDCs upon LPS stimulation was also assessed. The effect of PTX3 on whole blood coagulation was investigated using thromboelastometric analysis. TF expression in stationary moDCs treated with LPS and/or PTX3 was determined by measuring TF activity. The effect of complement inhibitors on TF activity in moDCs treated with LPS and/or PTX3 under low-shear conditions was evaluated.

RESULTS

PTX3 levels were higher in whole blood supplemented with moDCs than in the presence of monocytes and were further elevated by LPS stimulation. PTX3 release from generated moDCs was also increased by LPS stimulation. PTX3 reduced whole blood coagulation time in a dose-dependent manner. However, PTX3 did not increase TF expression in stationary moDCs. Under low-shear conditions, PTX3 increased TF expression in moDCs. C1 esterase inhibitor (C1-inh) suppressed this effect.

CONCLUSIONS

PTX3 might have a thrombophilic activity and enhance TF expression in moDCs under low-shear conditions. Furthermore, suppression of moDC-associated hypercoagulability by C1-inh might be partly ascribed to its inhibitory effect on PTX3.

Pentraxin 3 deficiency protects from the metabolic inflammation associated to diet-induced obesity

Aims

Low-grade chronic inflammation characterizes obesity and metabolic syndrome. Here, we aim at investigating the impact of the acute-phase protein long pentraxin 3 (PTX3) on the immune-inflammatory response occurring during diet-induced obesity.

Methods and results

PTX3 deficiency in mice fed a high-fat diet for 20 weeks protects from weight gain and adipose tissue deposition in visceral and subcutaneous depots. This effect is not related to changes in glucose homeostasis and lipid metabolism but is associated with an improved immune cell phenotype in the adipose tissue of Ptx3 deficient animals, which is characterized by M2-macrophages polarization and increased angiogenesis. These findings are recapitulated in humans where carriers of a PTX3 haplotype (PTX3 h2/h2 haplotype), resulting in lower PTX3 plasma levels, presented with a reduced prevalence of obesity and decreased abdominal adiposity compared with non-carriers.

Conclusion

Our results support a critical role for PTX3 in the onset of obesity by promoting inflammation and limiting adipose tissue vascularization and delineate PTX3 targeting as a valuable strategy for the treatment of adipose tissue-associated inflammatory response.

PTX3, a Humoral Pattern Recognition Molecule, in Innate Immunity, Tissue Repair, and Cancer

Innate immunity includes a cellular and a humoral arm. PTX3 is a fluid-phase pattern recognition molecule conserved in evolution which acts as a key component of humoral innate immunity in infections of fungal, bacterial, and viral origin. PTX3 binds conserved microbial structures and self-components under conditions of inflammation and activates effector functions (complement, phagocytosis). Moreover, it has a complex regulatory role in inflammation, such as ischemia/reperfusion injury and cancer-related inflammation, as well as in extracellular matrix organization and remodeling, with profound implications in physiology and pathology. Finally, PTX3 acts as an extrinsic oncosuppressor gene by taming tumor-promoting inflammation in murine and selected human tumors. Thus evidence suggests that PTX3 is a key homeostatic component at the crossroad of innate immunity, inflammation, tissue repair, and cancer. Dissecting the complexity of PTX3 pathophysiology and human genetics paves the way to diagnostic and therapeutic exploitation.

Sub-Chronic Stress Exacerbates the Pro-Thrombotic Phenotype in BDNFVal/Met Mice: Gene-Environment Interaction in the Modulation of Arterial Thrombosis

Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism has been associated with increased susceptibility to develop mood disorders and recently it has been also linked with cardiovascular disease (CVD). Interestingly, stressful conditions unveil the anxious/depressive-like behavioral phenotype in heterozygous BDNFVal66Met (BDNF^Val/Met) mice, suggesting an important relationship in terms of gene-environment interaction (GxE). However, the interplay between stress and BDNF^Val/Met in relation to CVD is completely unknown. Here, we showed that BDNF^Val/Met mice display a greater propensity to arterial thrombosis than wild type BDNF^Val/Val mice after 7 days of restraint stress (RS). RS markedly increased the number of leukocytes and platelets, and induced hyper-responsive platelets as showed by increased circulating platelet/leukocyte aggregates and enhanced expression of P-selectin and GPIIbIIIa in heterozygous mutant mice. In addition, stressed BDNF^Val/Met mice had a greater number of large and reticulated platelets but comparable number and maturation profile of bone marrow megakaryocytes compared to BDNF^Val/Val mice. Interestingly, RS led to a significant reduction of BDNF expression accompanied by an increased activity of tissue factor in the aorta of both BDNF^Val/Val and BDNF^Val/Met mice. In conclusion, we provide evidence that sub-chronic stress unveils prothrombotic phenotype in heterozygous BDNF Val66Met mice affecting both the number and functionality of blood circulating cells, and the expression of key thrombotic molecules in aorta. Human studies will be crucial to understand whether this GxE interaction need to be taken into account in risk stratification of coronary artery disease (CAD) patients.

Long Pentraxin-3 Modulates the Angiogenic Activity of Fibroblast Growth Factor-2

Angiogenesis, the process of new blood vessel formation from pre-existing ones, plays a key role in various physiological and pathological conditions. Alteration of the angiogenic balance, consequent to the deranged production of angiogenic growth factors and/or natural angiogenic inhibitors, is responsible for angiogenesis-dependent diseases, including cancer. Fibroblast growth factor-2 (FGF2) represents the prototypic member of the FGF family, able to induce a complex “angiogenic phenotype” in endothelial cells in vitro and a potent neovascular response in vivo as the consequence of a tight cross talk between pro-inflammatory and angiogenic signals. The soluble pattern recognition receptor long pentraxin-3 (PTX3) is a member of the pentraxin family produced locally in response to inflammatory stimuli. Besides binding features related to its role in innate immunity, PTX3 interacts with FGF2 and other members of the FGF family via its N-terminal extension, thus inhibiting FGF-mediated angiogenic responses in vitro and in vivo. Accordingly, PTX3 inhibits the growth and vascularization of FGF-dependent tumors and FGF2-mediated smooth muscle cell proliferation and artery restenosis. Recently, the characterization of the molecular bases of FGF2/PTX3 interaction has allowed the identification of NSC12, the first low molecular weight pan-FGF trap able to inhibit FGF-dependent tumor growth and neovascularization. The aim of this review is to provide an overview of the impact of PTX3 and PTX3-derived molecules on the angiogenic, inflammatory, and tumorigenic activity of FGF2 and their potential implications for the development of more efficacious anti-FGF therapeutic agents to be used in those clinical settings in which FGFs play a pathogenic role.

Tanshinone IIA attenuates TNF-α induced PTX3 expression and monocyte adhesion to endothelial cells through the p38/NF-κB pathway

Tanshinone IIA is one of the most predominant bioactive constituents of Danshen, a traditional Chinese medicinal plant with multiple cardiovascular protective actions. Although Tanshinone IIA has been well documented for its endothelial protective efficacy, studies unveiling the mechanism and/or molecular targets for its pharmacological activity are still inadequate. In recent studies, it has been envisaged that the expression of pentraxin 3 (PTX3) was associated with atherosclerotic cardiovascular diseases (ACVD). Therefore, the current study was designed to evaluate the possible role of Tanshinone IIA in influencing the expression of PTX3 in endothelial cells and thereby prevents endothelial dysfunction. Molecular analyses through real-time PCR, western blot, and ELISA revealed that Tanshinone IIA down-regulates PTX3 gene expression as well as protein secretion in human endothelial cells in the presence or absence of TNF-α. Besides, Tanshinone IIA inhibits the adhesion of THP1 cells (a monocytic cell line) to activated-endothelial cells stimulated with TNF-α. Furthermore, mechanistic studies uncovered the role of p38 MAPK/NF-κB pathway in Tanshinone II-A mediated pharmacological effects. Thus, the present study exemplifies the manifestation of Tanshinone IIA as a plausible alternative natural remedy for ACVD by targeting PTX3.

Pentraxin 3 promotes cardiac differentiation of mouse embryonic stem cells through JNK signaling pathway

Cardiovascular disease is a leading cause of death worldwide, requiring the development of new therapeutic strategies including stem cell therapy. Pentraxins (PTXs) are a superfamily of proteins highly involved in different myocardial disorders, and thus this study aimed to identify the modulation of long pentraxin 3 (PTX3) in the differentiation of mouse embryonic stem cells (mESCs) toward cardiomyocytes. Cell toxicity of PTX3 was detected by MTT and LDH assays in mESCs. Embryoid bodies (EBs) were differentiated using hanging drop method, and the beating was observed under microscope. Expressional levels of early cardiac progenitor marker genes were assessed by qRT-PCR. Expression of marker proteins in early myocardial development and the activation of JNK signaling pathway was evaluated by Western blot. PTX3 treatment at 50 ng/mL significantly promoted the expression of cardiac-specific marker genes including Nkx2.5, Mef2c, Tbx5, dHand, and αMHC, and increased the expression of cardiac maturity indicative markers including connexin 43 and troponin C1. PTX3 enhanced the phosphorylation of JNK across the incubation duration, whereas the activation of p38 remained the same as control group. Co-treatment of JNK signaling pathway inhibitor SP600125 impaired the PTX3-promoted transcription of Nkx2.5, Mef2c, Tbx5, dHand, and αMHC. This study revealed the promotion of PTX3 in the differentiation of mESCs into cardiomyocytes and the underlying mechanism.

The Effects of Curcumae Longae Radix, Curcuma phaeocaulis Radix and Their Processed Products on Epo/EpoR Pathway and CD62p

Background: Curcumae Radix (Yujin) has been widely used to treat Qi stagnation due to Liver depression (LDQS) in traditional Chinese medicine (TCM) for a long time and is good at dispelling melancholy by soothing liver to regulate qi and relieving pain by promoting blood circulation for removing blood stasis. Yujin stir-frying with vinegar can strengthen the effect of dispersing stagnated hepatoqi to stop pain by injecting medicine into the liver and stir-frying with wine can strengthen the effect of promoting blood circulation for removing blood stasis. Because the reason for the enhancement of clinical efficacy by processing is unclear, it is difficult to select and use processed products in the clinic. Aim/Hypothesis: In this study, from the point of view of the platelet function, we start to investigate the mechanism for promoting blood circulation, removing blood stasis, and enhancing clinical efficacy by processing. Methods: This study mainly takes Curcumae Longae Radix (HSYJ) and Curcuma phaeocaulis Radix (LSYJ) as the research subjects. They are genuine drugs in Sichuan Province, China. A high-performance liquid chromatography (HPLC) is used to analyze the main chemical constituents of Yujin and its processed products, and show the difference between the two species, with and without processing. A rat model of blood stasis induced by LDQS is established by giving the tail clamp stimulation, injecting epinephrine hydrochloride subcutaneously, and treating with an effective dose (0.9 g⋅kg^-1) according to the conversion of human clinical dosage for 2 weeks. After the experiment, the serum levels of erythropoietin are measured by ELISA. Furthermore, RT-PCR and WB are used to detect EpoR mRNA and protein expression in the hepatic tissue. Flow cytometry is used to measure peripheral blood CD62p expression. Results: There is a great difference between the chemical compositions of the two species, the number of chromatographic peaks of Curcumae Longae Radix is more than that of Curcuma phaeocaulis Radix. Curcuminoids is the main component of HSYJ, while curcuminoids is almost free from LSYJ. Curcuminoids is almost insoluble in water. After stir-frying with vinegar or wine, it can increase the dissolution of curcuminoids in water. In rat models, the levels of Epo, EpoR, and CD62p are significantly increased. After intragastric administration of Yujin, indicators show varying degrees of callback. HSYJ is better than LSYJ, and the processed product by stir-frying with wine is better than other processed products. Conclusion: The results show that the mechanism of promoting blood circulation for removing blood stasis in Yujin may be able to inhibit the activation and aggregation of platelets by intervening the Epo/EpoR pathway and regulating CD62p down. Stir-frying with wine can enhance this effect.

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.

Apocynin Prevents Abnormal Megakaryopoiesis and Platelet Activation Induced by Chronic Stress

Environmental chronic stress (ECS) has been identified as a trigger of acute coronary syndromes (ACS). Changes in redox balance, enhanced reactive oxygen species (ROS) production, and platelet hyperreactivity were detected in both ECS and ACS. However, the mechanisms by which ECS predisposes to thrombosis are not fully understood. Here, we investigated the impact of ECS on platelet activation and megakaryopoiesis in mice and the effect of Apocynin in this experimental setting. ECS induced by 4 days of forced swimming stress (FSS) treatment predisposed to arterial thrombosis and increased oxidative stress (e.g., plasma malondialdehyde levels). Interestingly, Apocynin treatment prevented these alterations. In addition, FSS induced abnormal megakaryopoiesis increasing the number and the maturation state of bone marrow megakaryocytes (MKs) and affecting circulating platelets. In particular, a higher number of large and reticulated platelets with marked functional activation were detected after FSS. Apocynin decreased the total MK number and prevented their ability to generate ROS without affecting the percentage of CD42d⁺ cells, and it reduced the platelet hyperactivation in stressed mice. In conclusion, Apocynin restores the physiological megakaryopoiesis and platelet behavior, preventing the detrimental effect of chronic stress on thrombosis, suggesting its potential use in the occurrence of thrombosis associated with ECS.

Impairment of PTX3 expression in osteoblasts: a key element for osteoporosis

Pentraxin 3 (PTX3) is a multifunctional glycoprotein regulating inflammatory response, cell proliferation and migration and deposition and remodelling of the extracellular matrix by a variety of cells. In this study, we investigated the possible role of PTX3 in bone homeostasis. To this end, we compared the expression and function of PTX3 in human osteoblasts of osteoporotic, osteoarthritic patients and young subjects not affected by bone diseases. Immunohistochemical analysis performed on bone head biopsies showed a close association between bone health and the number of osteoblasts expressing PTX3. Noteworthy, the proportion of PTX3-positive osteoblasts resulted to be significantly lower in osteoporotic patients compared with both young patients and osteoarthritic patients of the same age. Ex vivo culture of osteoblasts isolated from the three groups of patients confirmed in vivo observation. Specifically, we observed rare runt-related transcription factor 2 (RUNX2) immunopositive osteoblasts expressing PTX3 in cell cultures derived from osteoporotic patients and western blotting analysis showed 80% reduction of PTX3 in the corresponding culture extracts compared with young and osteoarthritic patients. The treatment of human osteoblast primary cultures derived from young patients with anti-PTX3 antibody dramatically affected osteoblast behaviour. Indeed, they lost the morphological and molecular features typical of mature osteoblasts, acquiring fibroblast-like shape and highly decreasing nuclear factor kappa-B ligand (RANKL) and RUNX2 expression. Also, the inhibition of PTX3 negatively affected osteoblast proliferation and their ability to form cell clusters and microhydroxyapatite crystals. Altogether, these results suggest a central role of PTX3 in bone homeostasis showing its involvement in osteoblast proliferation, differentiation and function.

Relationship Between Plasma Pentraxin 3 Concentration and Platelet Indices in Patients With Stable Coronary Artery Disease

Few reports have analyzed the effect of pentraxin 3 (PTX3) on platelets and their activation. We explored the association between plasma PTX3 and platelet indices. Forty-nine patients with stable coronary artery disease (CAD) were enrolled. Based on median PTX3, the study population was divided into group 1 (n = 25; PTX3 ≤ 0.98 ng/mL) and group 2 (n = 24; PTX3 > 0.98 ng/mL). Platelet indices investigated included mean platelet volume (MPV), platelet distribution width (PDW), platelets and large cell ratio (P-LCR), MPV to platelet count ratio (MPV/PC), platelet to lymphocyte ratio (PLR), and MPV to lymphocyte ratio (MPVLR). Patients with lower PTX3 had a higher lymphocyte count. Platelet count was similar in both groups. Notwithstanding, patients with higher PTX3 concentrations had elevated MPV (8.3 vs 10.0 fL; P < .001) and PDW (9.4 vs 12.4 fL; P < .001). However, the MPV/PC ratio was similar in both groups. Thromboinflammatory biomarkers (PLR, MPVLR) were also elevated in group 2. Pentraxin 3showed a strong, positive correlation with MPV ( r = .75, P < .01) and PDW ( r = .80, P < .01), and weak to moderate correlation with MPVLR. In conclusion, PTX3 is associated with larger platelet size as assessed by platelet volume indices. There is a strong correlation between plasma PTX3 level and MPV and PDW.

Driver mutations (JAK2V617F, MPLW515L/K or CALR), pentraxin-3 and C-reactive protein in essential thrombocythemia and polycythemia vera

Background

The driver mutations JAK2V617F, MPLW515L/K and CALR influence disease phenotype of myeloproliferative neoplasms (MPNs) and might sustain a condition of chronic inflammation. Pentraxin 3 (PTX3) and high-sensitivity C-reactive protein (hs-CRP) are inflammatory biomarkers potentially useful for refining prognostic classification of MPNs.

Methods

We evaluated 305 with essential thrombocythemia (ET) and 172 polycythemia vera (PV) patients diagnosed according to the 2016 WHO criteria and with full molecular characterization for driver mutations.

Results

PTX3 levels were significantly increased in carriers of homozygous JAK2V617F mutation compared to all the other genotypes and triple negative ET patients, while hs-CRP levels were independent of the mutational profile. The risk of haematological evolution and death from any cause was about 2- and 1.5-fold increased in individuals with high PTX-3 levels, while the thrombosis rate tended to be lower. High hs-CRP levels were associated with risk of haematological evolution, death and also major thrombosis. After sequential adjustment for potential confounders (age, gender, diagnosis and treatments) and the presence of JAK2V617F homozygous status, high hs-CRP levels remained significant for all outcomes, while JAK2V617F homozygous status as well as treatments were the factors independently accounting for adverse outcomes among patients with high PTX3 levels.

Conclusions

These results provide evidence that JAK2V617F mutation influences MPN-associated inflammation with a strong correlation between allele burden and PTX3 levels. Plasma levels of hs-CRP and PTX3 might be of prognostic value for patients with ET and PV, but their validation in future prospective studies is needed.

Innate immunity, hemostasis and matrix remodeling: PTX3 as a link

Innate immunity is evolutionarily connected with hemostasis. PTX3 is an essential fluid-phase pattern recognition molecule of the innate immune system that acts as a functional ancestor of antibodies. PTX3 by interacting with defense collagens and fibrinogens amplifies effector functions of the innate immune system. At wound sites, PTX3 regulates the injury-induced thrombotic response and promotes wound healing by favoring timely fibrinolysis. Therefore, PTX3 interacts with ancestral domains conserved in innate immunity, hemostasis and extracellular matrix and exerts functions related to both antimicrobial resistance and tissue repair. These findings strengthen the connection between innate immune system and hemostasis, and suggest that recognition of microbes and extracellular matrix are evolutionarily conserved and integrated functions of the innate immune system.

The inflammatory protein Pentraxin 3 in cardiovascular disease

The acute phase protein Pentraxin 3 (PTX3) plays a non-redundant role as a soluble pattern recognition receptor for selected pathogens and it represents a rapid biomarker for primary local activation of innate immunity and inflammation. Recent evidence indicates that PTX3 exerts an important role in modulating the cardiovascular system in humans and experimental models. In particular, there are conflicting points concerning the effects of PTX3 in cardiovascular diseases (CVD) since several observations indicate a cardiovascular protective effect of PTX3 while others speculate that the increased plasma levels of PTX3 in subjects with CVD correlate with disease severity and with poor prognosis in elderly patients.

In the present review, we discuss the multifaceted effects of PTX3 on the cardiovascular system focusing on its involvement in atherosclerosis, endothelial function, hypertension, myocardial infarction and angiogenesis. This may help to explain how the specific modulation of PTX3 such as the use of different dosing, time, and target organs could help to contain different vascular diseases. These opposite actions of PTX3 will be emphasized concerning the modulation of cardiovascular system where potential therapeutic implications of PTX3 in humans are discussed.

Humoral innate immunity at the crossroad between microbe and matrix recognition: The role of PTX3 in tissue damage

Innate immunity is involved in regulating inflammatory and tissue repair responses to injury. In particular, humoral innate immunity plays functions related to wound clearance from tissue debris, and regulation of macrophage and stromal cell activities. PTX3, a component of humoral innate immunity, orchestrates tissue repair by interacting with plasminogen and fibrin. Fluid-phase molecules of innate immunity interact with elements of the extracellular matrix, and some of the latter display opsonic activity against certain bacterial species.

Thus, recognition of extracellular matrix and microbial components is a recurrent theme in the humoral arm of the innate immune system.