Association of EGF Receptor and NLRs signaling with Cardiac Inflammation and Fibrosis in Mice Exposed to Fine Particulate Matter

Combined transcriptome and microbiome analysis reveals the thyrotoxic effects of PM2.5 in female rats

Pervasive environmental pollutants, specifically particulate matter (PM2.5), possess the potential to disrupt homeostasis of female thyroid hormone (TH). However, the precise mechanism underlying this effect remains unclear. In this study, we established a model of PM2.5-induced thyroid damage in female rats through intratracheal instillation and employed histopathological and molecular biological methods to observe the toxic effects of PM2.5 on the thyroid gland. Transcriptome gene analysis and 16S rRNA sequencing were utilized to investigate the impact of PM2.5 exposure on the female rat thyroid gland. Furthermore, based on the PM2.5-induced toxic model in female rats, we evaluated its effects on intestinal microbiota, TH levels, and indicators of thyroid function. The findings revealed that PM2.5 exposure induced histopathological damage to thyroid tissue by disrupting thyroid hormone levels (total T3 [TT3], (P < 0.05); total T4 [TT4], (P < 0.05); and thyrotropin hormone [TSH], (P < 0.05)) and functional indices (urine iodine [UI], P > 0.05), thus further inducing histopathological injuries. Transcriptome analysis identified differentially expressed genes (DEGs), primarily concentrated in interleukin 17 (IL-17), forkhead box O (FOXO), and other signaling pathways. Furthermore, exposure to PM2.5 altered the composition and abundance of intestinal microbes. Transcriptome and microbiome analyses demonstrated a correlation between the DEGs within these pathways and the flora present in the intestines. Moreover, 16 S rRNA gene sequencing analysis or DEGs combined with thyroid function analysis revealed that exposure to PM2.5 significantly induced thyroid hormone imbalance. We further identified key DEGs involved in thyroid function-relevant pathways, which were validated using molecular biology methods for clinical applications. In conclusion, the homeostasis of the "gut-thyroid" axis may serve as the underlying mechanism for PM2.5-induced thyrotoxicity in female rats.

NLRP12 attenuates ozone-induced pulmonary inflammation by regulating canonical NF-κB Pathway

Ozone (O3) is an important urban air pollutant having strong correlations with respiratory diseases. Several lines of evidence suggest that O3 exposure causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Inhibitory innate immune receptors, such as NLRP12, have been demonstrated to alleviate inflammation, but the functional role for NLRP12 in O3-induced lung inflammatory inflammation remains to be reported. Here, we determined whether NLRP12 took a protective role in O3-induced AHR and pulmonary inflammation via the suppression of canonical NF-κB. C57BL/6 J mice were exposed to filtered air (FA) or 0.25, 0.50 and 1.00 ppm (3 h/day for 5 consecutive days) followed by detection of airway resistance, white blood cells, total proteins, and cytokines. Meanwhile, NLRP12 in lung tissue were detected by real time PCR. Moreover, we also examined protein expression of NLRP12 and key biomarkers of NF-κB pathway. It was shown that 24 h post O3 exposure, AHR as wells as total cells, proteins, and cytokines contents in BALF of mice were increased compare to those of FA controls in a dose-dependent manner. Notably, O3-induced AHR and lung inflammation were associated with significant decrease in pulmonary NLRP12 and upregulation of phosphorylated IRAK1, p65 and IκBα in canonical NF-κB pathway. Intratracheal administration of NLRP12-overexpresing adenovirus 4 days prior to O3 exposure alleviated AHR and lung inflammation, and inhibited canonical NF-κB pathway activation. The findings from this study indicate that NLRP12 attenuates O3-induced AHR and pulmonary inflammation, possibly through regulating canonical NF-κB pathway. This provides a novel target for the prevention and treatment of lung diseases induced by O3 exposure.

Adverse effects of air pollution-derived fine particulate matter on cardiovascular homeostasis and disease

Air pollution is a rapidly growing major health concern around the world. Atmospheric particulate matter that has a diameter of less than 2.5 µm (PM2.5) refers to an air pollutant composed of particles and chemical compounds that originate from various sources. While epidemiological studies have established the association between PM2.5 exposure and cardiovascular diseases, the precise cellular and molecular mechanisms by which PM2.5 promotes cardiovascular complications are yet to be fully elucidated. In this review, we summarize the various sources of PM2.5, its components, and the concentrations of ambient PM2.5 in various settings. We discuss the experimental findings to date that evaluate the potential adverse effects of PM2.5 on cardiovascular homeostasis and function, and the possible therapeutic options that may alleviate PM2.5-driven cardiovascular damage.

Inhibiting EGFR/HER-2 ameliorates neuroinflammatory responses and the early stage of tau pathology through DYRK1A

The FDA-approved EGFR/HER2 inhibitor varlitinib inhibits tumor growth and is used in cancer treatment. However, the neuroinflammatory response associated with EGFR/HER2 and its underlying mechanism have not been elucidated. This study evaluates the impact of varlitinib on LPS- and tau-mediated neuroinflammatory responses for the first time. In BV2 microglial cells, varlitinib reduced LPS-stimulated il-1β and/or inos mRNA levels and downstream AKT/FAK/NF-kB signaling. Importantly, varlitinib significantly diminished LPS-mediated microglial nlrp3 inflammasome activation in BV2 microglial cells. In primary astrocytes, varlitinib downregulated LPS-evoked astroglial il-1β mRNA levels, AKT signaling, and nlrp3 inflammasome activation. In LPS-treated wild-type mice, varlitinib significantly reduced LPS-stimulated glial activation and IL-1β/NLRP3 inflammasome formation. Moreover, varlitinib significantly reduced micro- and astroglial activation and tau hyperphosphorylation in 3-month-old tau-overexpressing PS19 mice by downregulating tau kinase DYRK1A levels. However, in 6-month-old tau-overexpressing PS19 mice, varlitinib only significantly diminished astroglial activation and tau phosphorylation at Thr212/Ser214. Taken together, our findings suggest that varlitinib has therapeutic potential for LPS- and tau-induced neuroinflammatory responses and the early stages of tau pathology.

Alterations in the gut microbiota and its metabolic profile of PM2.5 exposure-induced thyroid dysfunction rats

Fine particulate matter (PM_2.5) has drawn more and more interest due to its adverse effects on health. Thyroid has been demonstrated to be the key organ impacted by PM_2.5. However, the mechanisms for PM_2.5 exposure-induced thyrotoxicity remain unclear. To explore the mechanisms, a rat thyroid injury model was established by exposing rats to PM_2.5 via passive pulmonary inhalation. Thyroid hormones and thyroid function proteins were detected. The thyroid function affected by PM_2.5 exposure was investigated via metabolomics analysis using liquid chromatography-mass spectrometry and 16S rRNA gene sequencing. Results showed that PM_2.5 exposure induced remarkable alterations in gut microbiome evenness, richness, and composition. Metabolomics profiling revealed that the urine metabolites levels were changed by PM_2.5 exposure. The altered gut microbiota and urine metabolites showed significant correlations with thyroid function indicators (total T3, total T4 and thyrotropin hormone, etc.). These metabolites were involved in metabolic pathways including thyroid hormone synthesis, metabolisms of tryptophan, d-Glutamine and D-glutamate, histidine, glutathione, etc. The altered gut microbiota showed significant correlations with urine metabolites (glutathione, citric acid, D-Glutamic acid, kynurenic acid and 5-Aminopentanoic acid, etc.). For example, the taurocholic acid levels positively correlated with the relative abundance of several genera including Elusimicrobium (r = 0.9741, p = 0.000000), Muribaculum (r = 0.9886, p = 0.000000), Candidatus_Obscuribacter (r = 0.8423, p = 0.000585), Eubacterium (r = 0.9237, p = 0.000017), and Parabacteroides (r = 0.8813, p = 0.000150), while it negatively correlated with the relative abundance of Prevotella (r = -0.8070, p = 0.001509). PM_2.5 exposure-induced thyrotoxicity led to remarkable alterations both in gut microbiome composition and some metabolites involved in metabolic pathways. The altered intestinal flora and metabolites can in turn influence thyroid function in rats. These findings may provide novel insights regarding perturbations of the gut-thyroid axis as a new mechanism for PM_2.5 exposure-induced thyrotoxicity.

[Angiotensin-converting enzyme 2 particapates in ozone-induced lung inflammation and airway remodeling in mice]

OBJECTIVE

To investigate the roles of angiotensin-converting enzyme 2 (ACE2) in ozone-induced pulmonary inflammation and airway remodeling in mice.

METHODS

Sixteen wild-type (WT) C57BL/6J mice and 16 ACE2 knock-out (KO) mice were exposed to either filtered air or ozone (0.8 ppm) for 3 h per day for 5 consecutive days. Masson's staining and HE staining were used to observe lung pathologies. Bronchoalveolar lavage fluid (BALF) was collected and the total cell count was determined. The total proteins and cytokines in BALF were determined by BCA and ELISA method. The transcription levels of airway remodeling-related indicators in the lung tissues were detected using real-time quantitative PCR. The airway resistance of the mice was measured using a small animal ventilator with methacholine stimulation.

RESULTS

Following ozoneexposure ACE2 KO mice had significantly higher lung pathological scores than WT mice (P < 0.05). Masson staining results showed that compared with ozone-exposed WT mice, ozone-exposed ACE2 KO mice presented with significantly larger area of collagen deposition in the bronchi [(19.62±3.16)% vs (6.49±1.34)%, P < 0.05] and alveoli [(21.63±3.78)% vs (4.44±0.99)%, P < 0.05]. The total cell count and total protein contents in the BALF were both higher in ozone-exposed ACE2 KO mice than in WT mice, but these differences were not statistically significant (P > 0.05). The concentrations of IL-6, IL-1β, TNF-α, CXCL1/KC and MCP-1 in the BALF were all higher in ozone-exposed ACE2 KO mice than in ozone-exposed WT mice, but only the difference in IL-1β was statistically significant (P < 0.05). The transcription levels of MMP-9, MMP-13, TIMP 4, COL1A1, and TGF-β in the lung tissues were all significantly higher in ozone-exposed ACE2 KO mice (P < 0.01). No significant difference was found in airway resistance between ozone-exposed ACE KO mice and WT mice after challenge with 0, 10, 25, or 100 mg/mL of methacholine.

CONCLUSION

ACE2 participates in ozone-induced lung inflammation and airway remodeling in mice.

Role of angiotensin-converting enzyme 2 in fine particulate matter-induced acute lung injury

Fine particulate matter (PM2.5) pollution poses significant health concerns worldwide and can cause respiratory diseases. However, how it causes health problems is still poorly understood. Angiotensin-converting enzyme (ACE)2 is a terminal carboxypeptidase implicated in the functions of renin-angiotensin system (RAS) and plays a crucial role in the control of lung inflammation. To investigate whether ACE2 functions in PM2.5-induced lung inflammation, wild-type (WT) C57BL/6J mice and ACE2 knock-out (KO) mice were intratracheally instilled with PBS or PM2.5 suspension for 3 consecutive days, respectively. The concentrations of cytokines in bronchoalveolar lavage fluid (BALF) were determined by ELISA. The expression of ACE2 and ACE and activation of inflammatory signaling pathways in lung tissues were evaluated by immunofluorescence staining and Western blotting. We found that PM2.5 exposure increased ACE2 expression. Loss of ACE2 significantly elevated the levels of total proteins, total cells, and the concentrations of MCP-1, IL-1β in BALF after PM2.5 challenge. Additionally, loss of ACE2 enhanced lung pathologies, airway resistance, and inflammatory signaling activation. Collectively, loss of ACE2 exacerbates PM2.5-induced acute lung injury in mice.

A Review of CXCL1 in Cardiac Fibrosis

Chemokine C-X-C motif ligand-1 (CXCL1), principally expressed in neutrophils, macrophages and epithelial cells, is a valid pro-inflammatory factor which performs an important role in mediating the infiltration of neutrophils and monocytes/macrophages. Elevated serum level of CXCL1 is considered a pro-inflammatory reaction by the organism. CXCL1 is also related to diverse organs fibrosis according to relevant studies. A growing body of evidence suggests that CXCL1 promotes the process of cardiac remodeling and fibrosis. Here, we review structure and physiological functions of CXCL1 and recent progress on the effects and mechanisms of CXCL1 in cardiac fibrosis. In addition, we explore the role of CXCL1 in the fibrosis of other organs. Besides, we probe the possibility that CXCL1 can be a therapeutic target for the treatment of cardiac fibrosis in cardiovascular diseases.

PM2.5 disrupts thyroid hormone homeostasis through activation of the hypothalamic-pituitary-thyroid (HPT) axis and induction of hepatic transthyretin in female rats 2.5

Fine particulate matter (PM_2.5), a ubiquitous environmental pollutant, has been indicated to affect thyroid hormone (TH) homeostasis in women, but the detailed mechanism behind this effect remains unclear. The objective of this study was to evaluate the roles of the hypothalamic-pituitary-thyroid (HPT) axis and hepatic transthyretin in the thyroid-disrupting effects of PM_2.5. Sprague Dawley rats were treated with PM_2.5 (0, 15 and 30 mg/kg) by passive pulmonary inhalation for 49 days; and recovery experimental group rats were dosed with PM_2.5 (30 mg/kg) for 35 days, and no treatment was done during the subsequent 14 days. PM_2.5 was handled twice a day by passive pulmonary inhalation throughout the study. After treatment, pathological changes were analyzed by performing haemotoxylin and eosin staining, measuring levels of THs and urine iodine (UI) in serum, plasma, and urine samples using enzyme-linked immunoabsorbent assay, and expression of proteins in the hypothalamus, pituitary, thyroid, and liver tissues of rats were analyzed by immunohistochemistry and Western blotting. The levels of oxidative stress factors, such as reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (Gpx), and nuclear factor-kappa B (NF-κB) in female rats' plasma were also evaluated by ELISA. The results of these analyses revealed that PM_2.5 treatment induced pathologic changes in rat thyroid and liver characterized by increased follicular cavity size and decreased amounts of follicular epithelial cells and fat vacuoles, respectively. Serum levels of triiodothyronine, thyroxine, and thyroid stimulating hormone were significantly decreased, plasma NF-κB level was increased and plasma redox state was unbalanced (enhanced ROS, MDA and Gpx levels; reduced SOD activities) in female rats treated with PM_2.5 (P < 0.05). PM_2.5 treatment suppressed the biosynthesis and biotransformation of THs by increasing sodium iodide symporter, thyroid transcription factor 1, thyroid transcription factor 2, and paired box 8 protein expression levels (P < 0.05). Additionally, thyroid stimulating hormone receptor and thyroid peroxidase levels were significantly decreased (P < 0.05). Both thyrotropin releasing hormone receptor and thyroid stimulating hormone beta levels were enhanced (P < 0.05). Moreover, transport of THs was inhibited due to reduced protein expression of hepatic transthyretin upon treatment with PM_2.5. In summary, PM_2.5 treatment could perturb TH homeostasis by affecting TH biosynthesis, biotransformation, and transport, affecting TH receptor levels, and inducing oxidative stress and inflammatory responses. Activation of the HPT axis and altered hepatic transthyretin levels therefore appear to play a crucial role in PM_2.5-induced thyroid dysfunction.

Airborne particulate matter (PM2.5) triggers cornea inflammation and pyroptosis via NLRP3 activation

Although studies have demonstrated that fine particulate matter (PM_2.5) induces ocular surface damage, PM2.5 exposure causes cornea toxicity is not entirely clear. The aim of this study is to investigate the role of the nod-like receptor family pyrin domain containing three (NLRP3) inflammasome-mediated pyroptosis in PM_2.5-related corneal toxicity. Human corneal epithelial cells (HCECs) were exposed to different concentrations of PM_2.5, and the cell viability, expressions of NLRP3 inflammasome mediated pyroptosis axis molecules and intracellular reactive oxygen species (ROS) formation were measured in HCECs. Animal experiments were undertaken to topically apply PM_2.5 suspension to mouse eyes for three months and the pyroptosis related molecules in the mouse corneas were measured. RESULTS: Our results showed a dose-dependent decrease of HCEC viability in the PM_2.5-treated cells. NLRP3 inflammasome-mediated pyroptosis axis (NLRP3, ASC, GSDMD, caspase-1, IL-1β, and IL-18) were activated in the PM_2.5-treated HCECs, accompanied by increased ROS formation. Further in vivo study confirmed the activation of this pathway in the mouse corneas exposed to PM_2.5. In conclusion, this study provids novel evidence that PM_2.5 induces corneal toxicity by triggering cell pyroptosis.

NLRP3 Inflammasome: A Potential Therapeutic Target in Fine Particulate Matter-Induced Neuroinflammation in Alzheimer's Disease

As one of the most harmful air pollutants, fine particulate matter (PM2.5) has been implicated as a risk factor for multiple diseases, which has generated widespread public concern. Accordingly, a growing literature links PM2.5 exposure with Alzheimer's disease (AD). A critical gap in our understanding of the adverse effects of PM2.5 on AD is the mechanism triggered by PM2.5 that contributes to disease progression. Recent evidence has demonstrated that PM2.5 can activate NLRP3 inflammasome-mediated neuroinflammation. In this review, we highlight the novel evidence between PM2.5 exposure and AD incidence, which is collected and summarized from neuropathological, epidemiological, and neuroimaging studies to in-depth deciphering molecular mechanisms. First, neuropathological, epidemiological, and neuroimaging studies will be summarized. Then, the transport pathway for central nervous system delivery of PM2.5 will be presented. Finally, the role of NLRP3 inflammasome-mediated neuroinflammation in PM2.5 induced-effects on AD will be recapitulated.

Cardiovascular adaptations to particle inhalation exposure: molecular mechanisms of the toxicology

Ambient air, occupational settings, and the use and distribution of consumer products all serve as conduits for toxicant exposure through inhalation. While the pulmonary system remains a primary target following inhalation exposure, cardiovascular implications are exceptionally culpable for increased morbidity and mortality. The epidemiological evidence for cardiovascular dysfunction resulting from acute or chronic inhalation exposure to particulate matter has been well documented, but the mechanisms driving the resulting disturbances remain elusive. In the current review, we aim to summarize the cellular and molecular mechanisms that are directly linked to cardiovascular health following exposure to a variety of inhaled toxicants. The purpose of this review is to provide a comprehensive overview of the biochemical changes in the cardiovascular system following particle inhalation exposure and to highlight potential biomarkers that exist across multiple exposure paradigms. We attempt to integrate these molecular signatures in an effort to provide direction for future investigations. This review also characterizes how molecular responses are modified in at-risk populations, specifically the impact of environmental exposure during critical windows of development. Maternal exposure to particulate matter during gestation can lead to fetal epigenetic reprogramming, resulting in long-term deficits to the cardiovascular system. In both direct and indirect (gestational) exposures, connecting the biochemical mechanisms with functional deficits outlines pathways that can be targeted for future therapeutic intervention. Ultimately, future investigations integrating "omics"-based approaches will better elucidate the mechanisms that are altered by xenobiotic inhalation exposure, identify biomarkers, and guide in clinical decision making.

Subacute exposure of PM2.5 induces airway inflammation through inflammatory cell infiltration and cytokine expression in rats

Accumulating evidences support that exposure to fine particulate matter (PM_2.5) could cause inflammation of the airway, but its underlying mechanisms are less known. Our study aimed to explore the potential effect of non-canonical NF-κB signaling pathway in airway inflammation, which caused by PM_2.5, and the possible regulatory relationship between miR-6747-5p and NF-κB2. The histological analysis from in vivo study manifested that PM_2.5 could induce the exudation and infiltration of polymorphonuclear leukocytes (PMNs). Immunohistochemistry results of lung tissues showed that PM_2.5 increased ICAM-1, 6Ckine, SDF-1 and BAFF positive staining with a dose-dependent manner. In addition, PM_2.5 could induce the p52 nuclear translocation to trigger non-canonical NF-κB signaling pathway in lung tissues and BEAS-2B cells. Targetscan reporter gene assay showed that there was a target regulatory relationship between miR-6747-5p and NF-κB2. Besides, the chemical mimics of miR-6747-5p weakened the activation of non-canonical NF-κB signaling pathway induced by PM_2.5. In summary, exposure to PM_2.5 could trigger airway inflammation by activating the non-canonical NF-κB signaling pathway, which may be related to the negative feedback regulation mechanism of miR-6747-5p. Our findings will give new ideas into the toxic effects of airway inflammation triggered by PM_2.5.

NLRP3 inflammasome activation is associated with PM2.5 -induced cardiac functional and pathological injury in mice

Growing evidences indicate that inflammation induced by PM_2.5 exposure has been considered as a major driving force for the development of cardiovascular diseases. However, the mechanisms underlying PM_2.5 -induced cardiac injury remain unclear. This study aims to investigate the role of NLRP3 inflammasome in PM_2.5 -induced cardiac functional and pathological injury in mice. In this study, BALB/c mice were intratracheally instilled with PM_2.5 suspension (4.0 mg/kg BW) for 5 days to set up a cardiac injury model, which was evaluated by electrocardiogram monitoring, HE and Masson staining. Then, the effects of PM_2.5 on the expression of α-SMA, NLRP3, IL-1β, and IL-18 proteins and the activation of caspase-1 and IL-1β were investigated. The results showed that PM_2.5 exposure induced characteristic abnormal ECG changes such as the abnormality of heart rhythm, tachycardia, and T-wave reduction. Inflammatory cell infiltration and fibrosis were observed in the heart tissues of PM_2.5 -exposed mice. Meanwhile, PM_2.5 exposure increased the expression of α-SMA. And, NLRP3 activation-associated proteins of NLRP3, IL-1β, IL-18, Cleaved caspase-1 p10, and Cleaved IL-1β were upregulated in heart tissue of PM_2.5 -induced mice. In summary, PM_2.5 exposure could induce cardiac functional and pathological injury, which may be associated with the activation of NLRP3 inflammasome.

Ambient fine particulate matter induces inflammatory responses of vascular endothelial cells through activating TLR-mediated pathway

This study aims to investigate the role of Toll-like receptors (TLRs) on fine particulate matter (PM_2.5)-induced inflammatory responses of vascular endothelial cells. Inflammatory factors and TLRs were examined in the aorta of mice after nonsurgical intratracheal instillation of PM_2.5 as well as in the human umbilical vein endothelial cells (HUVECs) treated with PM_2.5. In addition, the effects of TLR2 and TLR4 inhibitors in the secretion of interleukin 6 (IL-6) and IL-1β and the expression of TLRs were determined in the HUVECs. The results showed that PM_2.5 could increase the expression of IL-1β, IL-6, TLR2, and TLR4 in vitro and in vivo. Anti-TLR2 IgG or TAK242, an inhibitor of TLR4, decreased the secretion of IL-1β and IL-6 by HUVECs and reduced the expression of corresponding TLRs. In conclusion, we demonstrate that both TLR2 and TLR4 are involved in PM_2.5-induced inflammatory responses of vascular endothelial cells. Inhibition of TLR2 and TLR4 expression has the potential to prevent PM_2.5-induced cardiovascular diseases.

Fine particulate matter (PM2.5) enhances FcεRI-mediated signaling and mast cell function

Persistent exposure to ambient fine particulate matter (PM_2.5) can exacerbate allergic diseases in humans. Mast cells play an important role in allergic inflammation in peripheral tissues, such as skin, mucosa, and lung. Engagement of the high-affinity Fc receptor leads to mast cell degranulation, releasing a variety of highly active mediators including histamine, leukotrienes, and inflammatory cytokines. How PM_2.5 exposure affects mast cell activation and function remains largely unknown. To characterize the effect of PM_2.5 on mast cells, we used bone marrow-derived mast cells (BMMCs) to examine whether PM_2.5 affected FcεRI-mediated signaling, cytokine production, and degranulation. Exposure to high doses of PM_2.5 caused pronounced apoptosis and death of BMMCs. In contrast, exposure to low doses of PM_2.5 enhanced mast cell degranulation and FcεRI-mediated cytokine production. Further analysis showed that PM_2.5 treatment increased Syk activation and subsequently phosphorylation of its substrates including LAT, PLC-γ1, and SLP-76. Moreover, PM_2.5 treatment led to activation of the PI3K and MAPK pathways. Intriguingly, water-soluble fraction of PM_2.5 were found responsible for the enhancement of FcεRI-mediated signaling, mast cell degranulation, and cytokine production. Our data suggest that PM_2.5, mainly water-soluble fraction of PM_2.5, could affect mast cell activation through enhancing FcεRI-mediated signaling.

Epigenetic hypomethylation and upregulation of NLRC4 and NLRP12 in Kawasaki disease

INTRODUCTION

Kawasaki disease (KD) is a type of childhood febrile systemic vasculitis. Inflammasomes control inflammatory signaling and are related with the development of KD. In this study, we performed a survey of transcripts and global DNA methylation levels of inflammasome sensors of NOD-like receptors (NLRs) and the downstream interleukin 1β (IL-1β).

MATERIALS AND METHODS

In this study, for the chip studies, we recruited a total of 18 KD patients, who we analyzed before receiving intravenous immunoglobulin (IVIG) and at least 3 weeks after IVIG treatment, as well as 36 non-fever controls by Illumina HumanMethylation 450 BeadChip and Affymetrix GeneChip® Human Transcriptome Array 2.0. A separate group of 78 subjects was performed for real-time quantitative PCR validations.

RESULTS

The expressions of mRNA levels of NLRC4, NLRP12, and IL-1β were significantly upregulated in KD patients compared to the controls (p<0.05). Once KD patients underwent IVIG treatment, these genes considerably decreased. In particular, the methylation status of the CpG sites of these genes indicated a significant opposite tendency between the KD patients and the controls. Furthermore, mRNA levels of IL-1β represented a positive correlation with NLRC4 (p=0.002). We also observed that the mRNA levels of NLRP12 were lower in KD patients who developed coronary arterial lesions (p<0.005).

CONCLUSION

This study is among the first to report epigenetic hypomethylation, increased transcripts, and the upregulation of NLRC4, NLRP12 and IL-1β in KD patients. Moreover, a decreased upregulation of NLRP12 was related to coronary arterial lesion formation in KD patients.

Air pollution is associated with the development of atherosclerosis via the cooperation of CD36 and NLRP3 inflammasome in ApoE-/- mice

Previous studies have indicated that the main air pollutant fine particulate matter (≤2.5 μm; PM_2.5) exposure is associated with the development of atherosclerosis. Although the mechanism is not fully illustrated, the inflammatory responses play an important role. The present study aimed to explore whether PM_2.5-exacerbated atherosclerosis was mediated by the cooperation of cluster of differentiation 36 (CD36) and nucleotide-binding oligomerization domain-like receptor protein (NLRP3) inflammasome in apolipoprotein E^-/- (ApoE^-/-) mice. Thirty-two ApoE^-/- mice were randomly divided into two groups. One group was fed with high fat chow (HFC) for 10 weeks to establish atherosclerotic model, and the other was fed with normal chow (NC). From week 11, the mice were exposed to concentrated PM_2.5 (PM) or filtered air (FA) using Shanghai Meteorological and Environmental Animal Exposure System for 16 weeks. In both NC and HFC groups, PM_2.5 exposure induced the formation of atherosclerosis plaque. Similarly, PM mice appeared higher lipid content in the aortic root than that in the FA mice. Compared with the FA mice, PM mice appeared a decrease in high density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 along with an increase in apolipoprotein B, low density lipoprotein-cholesterol (LDL-C) and oxidized low-density lipoprotein (ox-LDL). Moreover, PM_2.5 exposure induced increase of CD36 in serum and aorta. In both NC and HFC groups, NLRP3 inflammasome activation-related indicators were activated or increased in the aorta of the PM mice when compared with the FA mice. The cooperation of CD36 and NLRP3 inflammasome activation may be the potential mechanisms linkixposed to concentrated PM_2.5 (PM) or filtered air (FA) using Shanghai Meteorological and Environmental Animal Exposure System for 16 weeks. In both NC and HFC groups, PM_2.5 exposure induced the formation of atherosclerosis plaque. Similarly, PM mice appeared higher lipid content in the aortic root than that in the FA mice. Compared with the FA mice, PM mice appeared a decrease in high density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 along with an increase in apolipoprotein B, low density lipoprotein-cholesterol (LDL-C) and oxidized low-density lipoprotein (ox-LDL). Moreover, PM_2.5 exposure induced increase of CD36 in serum and aorta. In both NC and HFC groups, NLRP3 inflammasome activation-related indicators were activated or increased in the aorta of the PM mice when compared with the FA mice. The cooperation of CD36 and NLRP3 inflammasome activation may be the potential mechanisms linking air pollution and HFC-induced atherosclerosis even in the mice with NC intake.