PTX3: an inflammatory protein modulating ultrastructure and bioenergetics of human endothelial cells

Mitochondrial dysfunction as a key player in aggravating periodontitis among diabetic patients: review of the current scope of knowledge

Periodontitis is a prevalent inflammatory disease that leads to significant periodontal tissue destruction and compromised dental health, with its severity exacerbated in individuals with Diabetes Mellitus (DM). This review explores the complex relationship between mitochondrial dysfunction and periodontitis in diabetic patients. Recent studies indicate that the excessive production of reactive oxygen species (ROS), primarily generated by dysfunctional mitochondrial electron transport chain (ETC) complexes, contributes to oxidative stress (OS) and subsequent periodontal tissue damage. The interplay between impaired mitochondrial biogenesis, apoptosis of periodontal cells, and ROS accumulation highlights a critical area of concern in understanding the pathophysiology of diabetic periodontitis. Furthermore, altered glycemic control due to inflammatory processes associated with periodontitis may perpetuate a cyclical detriment to oral and systemic health. This review aims to highlight the mechanistic roles of mitochondrial dysfunction in the aggravation of periodontitis among diabetic patients, emphasizing further research to identify potential therapeutic targets and improve treatment efficacy for this dual pathology.

Pentraxin 3 deficiency ameliorates streptozotocin-induced pancreatic toxicity via regulating ER stress and β-cell apoptosis

The long pentraxin 3 (PTX3), a marker of inflammation, has been associated with cardiovascular disease, obesity, and metabolic syndrome. Recently, elevated serum PTX3 levels have been linked to type 2 diabetes in obese patients with nonalcoholic fatty liver disease. Diabetes mellitus is a metabolic syndrome characterized by hyperglycemia resulting from insufficient insulin secretion or action. However, the precise role of PTX3 in hyperglycemia remains unclear. This study aimed to investigate the physiological roles of PTX3 in vivo. The deformation of pancreatic islets was mitigated in PTX3-deficient mice treated with streptozotocin (STZ) compared to control C57BL/6J mice. In addition, PTX3 deficiency prevented STZ-induced unfolded protein responses and pancreatic β-cell death. Immunoblotting data revealed significant inhibition of inositol-requiring protein1α and C/EBP homologous protein (CHOP) protein expression in PTX3 KO mice administered tunicamycin which is a chemical endoplasmic reticulum stress inducer. Similarly, tunicamycin-induced Grp78, Grp94, ATF6, and CHOP mRNA levels were reduced in PTX3 KO mice. Moreover, recombinant PTX3-induced CHOP expression and β-cell apoptosis in primary mouse islets. These findings suggest that PTX3 plays a critical role in STZ-induced deformation of pancreatic islets via regulating endoplasmic reticulum stress and β-cell apoptosis.

Human Umbilical Vein Endothelial Cells as a Versatile Cellular Model System in Diverse Experimental Paradigms: An Ultrastructural Perspective

Human umbilical vein endothelial cells (HUVECs) are primary cells isolated from the vein of an umbilical cord, extensively used in cardiovascular studies and medical research. These cells, retaining the characteristics of endothelial cells in vivo, serve as a valuable cellular model system for understanding vascular biology, endothelial dysfunction, pathophysiology of diseases such as atherosclerosis, and responses to different drugs or treatments. Transmission electron microscopy (TEM) has been a cornerstone in revealing the detailed architecture of multiple cellular model systems including HUVECs, allowing researchers to visualize subcellular organelles, membrane structures, and cytoskeletal elements. Among them, the endoplasmic reticulum, Golgi apparatus, mitochondria, and nucleus can be meticulously examined to recognize alterations indicative of cellular responses to various stimuli. Importantly, Weibel-Palade bodies are characteristic secretory organelles found in HUVECs, which can be easily distinguished in the TEM. These distinctive structures also dynamically react to different factors through regulated exocytosis, resulting in complete or selective release of their contents. This detailed review summarizes the ultrastructural features of HUVECs and highlights the utility of TEM as a pivotal tool for analyzing HUVECs in diverse research frameworks, contributing valuable insights into the comprehension of HUVEC behavior and enriching our knowledge into the complexity of vascular biology.

Pentraxin 3: A promising therapeutic target for cardiovascular diseases

Cardiovascular disease (CVD) is the primary global cause of death, and inflammation is a crucial factor in the development of CVDs. The acute phase inflammatory protein pentraxin 3 (PTX3) is a biomarker reflecting the immune response. Recent research indicates that PTX3 plays a vital role in CVDs and has been investigated as a possible biomarker for CVD in clinical trials. PTX3 is implicated in the progression of CVDs through mechanisms such as exacerbating vascular endothelial dysfunction, affecting angiogenesis, and regulating inflammation and oxidative stress. This review summarized the structure and function of PTX3, focusing on its multifaceted effects on CVDs, such as atherosclerosis, myocardial infarction, and hypertension. This may help in explaining the varying PTX3 functions and usage, as well as in utilizing target organs to manage diseases. Moreover, elucidating the opposite role of PTX3 in the cardiovascular system will demonstrate the therapeutic and predictive potential in human diseases.

Dysregulated endothelial cell markers in systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVES

To perform a systematic literature review and meta-analysis on endothelial cell (EC) markers that are involved and dysregulated in systemic lupus erythematosus (SLE) in relation to disease activity, as EC dysregulation plays a major role in the development of premature atherosclerosis in SLE.

METHODS

Search terms were entered into Embase, MEDLINE, Web of Science, Google Scholar and Cochrane. Inclusion criteria were 1) studies published after 2000 reporting measurements of EC markers in serum and/or plasma of SLE patients (diagnosed according to ACR/SLICC criteria), 2) English language peer reviewed articles, and 3) disease activity measurement. For meta-analysis calculations, the Meta-Essentials tool by Erasmus Research Institute and of Management (ERIM) was used. Only those EC markers, which were 1) reported in at least two articles and 2) reported a correlation coefficient (i.e. Spearman's rank or Pearson's) between the measured levels of the EC marker and disease activity were included. For meta-analyses, a fixed effect model was used.

RESULTS

From 2133 hits, 123 eligible articles were selected. The identified SLE-related endothelial markers were involved in EC activation, EC apoptosis, disturbed angiogenesis, defective vascular tone control, immune dysregulation and coagulopathy. Meta-analyses of primarily cross-sectional studies showed significant associations between marker levels and disease activity for the following endothelial markers: Pentraxin-3, Thrombomodulin, VEGF, VCAM-1, ICAM-1, IP-10 and MCP-1. Dysregulated EC markers without associations with disease activity were: Angiopoeitin-2, vWF, P-Selectin, TWEAK and E-Selectin.

CONCLUSIONS

We provide a complete literature overview for dysregulated EC markers in SLE comprising a wide range of different EC functions. SLE-induced EC marker dysregulation was seen with, but also without, association with disease activity. This study provides some clarity in the eminent complex field of EC markers as biomarkers for SLE. Longitudinal data on EC markers in SLE are now needed to guide us more in unravelling the pathophysiology of premature atherosclerosis and cardiovascular events in SLE patients.

Pentraxin 3 regulated by miR-224-5p modulates macrophage reprogramming and exacerbates osteoarthritis associated synovitis by targeting CD32

Emerging evidence has shown an imbalance in M1/M2 macrophage polarization to play an essential role in osteoarthritis (OA) progression. However, the underlying mechanistic basis for this polarization is unknown. RNA sequencing of OA M1-polarized macrophages found highly expressed levels of pentraxin 3 (PTX3), suggesting a role for PTX3 in OA occurrence and development. Herein, PTX3 was found to be increased in the synovium and articular cartilage of OA patients and OA mice. Intra-articular injection of PTX3 aggravated, while PTX3 neutralization reversed synovitis and cartilage degeneration. No metabolic disorder or proteoglycan loss were observed in cartilage explants when treated with PTX3 alone. However, cartilage explants exhibited an OA phenotype when treated with culture supernatants of macrophages stimulated with PTX3, suggesting that PTX3 did not have a direct effect on chondrocytes. Therefore, the OA anti-chondrogenic effects of PTX3 are primarily mediated through macrophages. Mechanistically, PTX3 was upregulated by miR-224-5p deficiency, which activated the p65/NF-κB pathway to promote M1 macrophage polarization by targeting CD32. CD32 was expressed by macrophages, that when stimulated with PTX3, secreted abundant pro-inflammation cytokines that induced severe articular cartilage damage. The paracrine interaction between macrophages and chondrocytes produced a feedback loop that enhanced synovitis and cartilage damage. The findings of this study identified a functional pathway important to OA development. Blockade of this pathway and PTX3 may prevent and treat OA.

Role of the Extracellular Traps in Central Nervous System

It has been reported that several immune cells can release chromatin and granular proteins into extracellular space in response to the stimulation, forming extracellular traps (ETs). The cells involved in the extracellular trap formation are recognized including neutropils, macrophages, basophils, eosinophils, and mast cells. With the development of research related to central nervous system, the role of ETs has been valued in neuroinflammation, blood–brain barrier, and other fields. Meanwhile, it has been found that microglial cells as the resident immune cells of the central nervous system can also release ETs, updating the original understanding. This review aims to clarify the role of the ETs in the central nervous system, especially in neuroinflammation and blood–brain barrier.

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.

The long pentraxin PTX3: a novel serum marker to improve the prediction of osteoporosis and osteoarthritis bone-related phenotypes

Background

The long pentraxin PTX3 is generating great interest given the recent discovery of its involvement in bone metabolism. This study investigates the role of circulating PTX3 as a marker of bone-related phenotypes in patients with osteoporosis (OP) and osteoarthritis (OA).

Methods

Serum PTX3 levels were determined using an enzyme-linked immunosorbent assay (ELISA) in a total of OP (n=32), OA (n=19) patients and healthy controls (CTR; n=25). ROC curve analysis was carried out to evaluate the potential of PTX3 for the diagnosis of bone-related phenotypes. In addition, the association between PTX3 serum levels and biochemical markers was estimated by Spearman correlation analysis.

Results

Serum analysis reveals a statistically significant increase of PTX3 levels in OP and OA patients, compared to CTR subjects (**** p < 0.0001, **** p < 0.0001). ROC curve of PTX3 levels exhibits an excellent sensitivity and specificity for OP and OA diseases (**** p < 0.0001 and **** p < 0.0001, respectively). Moreover, serum PTX3 levels are positively associated with ALP (r = − 0.5257, p = 0.0083) and PTH levels (r = 0.4704, p = 0.0203) in OP patients.

Conclusions

These results confirm the pivotal role of PTX3 in bone metabolism and suggest its potential use as a predictor of OP and OA bone-related phenotypes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02440-3.

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.

Silencing of PTX3 alleviates LPS-induced inflammatory pain by regulating TLR4/NF-κB signaling pathway in mice

Pentraxin 3 (PTX3), an inflammatory marker and a pattern recognition receptor, plays an important role in promoting the progress of tumor and inflammatory diseases. However, the role of PTX3 in the pathogenesis of inflammatory pain diseases is rarely reported. The purpose of the present study is to investigate the effect of PTX3 on the progression of inflammatory pain and the special molecular mechanism. A mouse BV2 microglia cell activation-mediated inflammatory model was developed with Lipopolysaccharide (LPS) induction, and a mouse inflammatory pain model was established with LPS injection. The effect of PTX3 on microglia inflammatory activation was verified by measuring pro-inflammatory cytokines expression. The mechanical hyperalgesia testing, the thermal preference testing and the cold allodynia testing were used to measure the response of mice to mechanical pain, heat stimulation and cold stimulation, respectively. The results revealed that the expression of PTX3 was decreased in the LPS-induced inflammatory pain mice model. Silencing of PTX3 down-regulated LPS-induced inflammatory factors, including IL-6, NO and TNF-α, and alleviated LPS-induced inflammatory pain in BV2 cells. In addition, overexpression of TLR4 reversed the inhibitory effect of si-PTX3 on LPS-induced inflammatory response in BV2 cells. What is more, silencing of PTX3 inhibited TLR4/NF-κB signaling pathway. Collectively, it suggests that silencing of PTX3 alleviates LPS-induced inflammatory response of BV2 cells potentially by regulating the TLR4/NF-κB signaling pathway.