Diagnostic and prognostic values of HCG15 and morrbid in acute myocardial infarction

Background

Acute myocardial infarction (AMI) represents the gravest manifestation of ischemic heart disease, with the primary cause of mortality and morbidity worldwide. Although timely and accurate diagnosis of AMI is crucial in clinical practice, they are impeded by the limitation of current biomarkers. We aimed to explore the potential predictive value of two novel long non-coding RNA (lncRNA) HCG15 and Morrbid in AMI diagnosis and prognosis.

Method

We measured the lncRNA levels in the blood samples of 412 AMI patients and 111 healthy volunteers with the RT-PCR method. Receiver operating characteristic (ROC) curves were plotted to access the diagnostic value of selected lncRNAs. Restricted cubic splines (RCS) and the Kaplan-Meier method were utilized to examine the predictive value of the selected lncRNAs in AMI diagnosis.

Result

ROC curves identified an acceptable diagnostic value of HCG15 and Morrbid (AUC for HCG15: 0.937; AUC for Morrbid: 0.940). RCS and Kaplan-Meier analysis revealed the cut-off value of 3.6 for HCG15 and 4.0 for Morrbid have a good predictive value in MACCE within 12 months once AMI was diagnosed (p-value for HCG15: p = 0.025; p-value for Morrbid: p < 0.0001).

Conclusion

HCG15 and Morrbid were confirmed as promising lncRNA biomarkers for both diagnosis and prognosis of AMI in this study. Additionally, their importance of application in real-world clinical practice and underlying mechanisms in AMI diagnosis and prognosis remain to be explored.

An umbrella review of the evidence associating occupational carcinogens and cancer risk at 19 anatomical sites

Occupational exposure to carcinogens of increasing cancer risk have been extensively suggested. A robust assessment of these evidence is needed to guide public policy and health care. We aimed to classify the strength of evidence for associations of 13 occupational carcinogens (OCs) and risk of cancers. We searched PubMed and Web of Science up to November 2022 to identify potentially relevant studies. We graded the evidence into convincing, highly suggestive, suggestive, weak, or not significant according to a standardized classification based on: random-effects p value, number of cancer cases, 95% confidence interval of largest study, heterogeneity between studies, 95% prediction interval, small study effect, excess significance bias and sensitivity analyses with credibility ceilings. The quality of meta-analysis was evaluated by AMSTAR 2. Forty-eight articles yielded 79 meta-analyses were included in current umbrella review. Evidence of associations were convincing (class I) or highly suggeastive (class II) for asbestos exposure and increasing risk of lung cancer among smokers (RR = 8.79, 95%CI: 5.81-13.25 for cohort studies and OR = 8.68, 95%CI: 5.68-13.24 for case-control studies), asbestos exposure and increasing risk of mesothelioma (RR = 4.61, 95%CI: 2.57-8.26), and formaldehyde exposure and increasing risk of sinonasal cancer (RR = 1.68, 95%CI: 1.38-2.05). Fifteen associations were supported by suggestive evidence (class III). In summary, the current umbrella review found strong associations between: asbestos exposure and increasing risk of lung cancer among smokers; asbestos exposure and increasing risk of mesothelioma; and formaldehyde exposure and higher risk of sinonasal cancer. Other associations might be genuine, but substantial uncertainty remains.

Non-coding RNAs: A new frontier in benzene-mediated toxicity

One of the most frequent environmental contaminants, benzene is still widely used as an industrial solvent around the world, especially in developing nations, posing a serious occupational risk. While the processes behind the toxicity of benzene grounds are not fully understood, it is generally accepted that its metabolism, which involves one or more reactive metabolites, is crucial to its toxicity. In order to evaluate the many ways that benzene could influence gene regulation and thus have an impact on human health, new methodologies have been created. The pathophysiology of the disorder may result from epigenetic reprogramming caused by exposure to benzene, including changes in non-coding RNA (ncRNA) markers, according to recent studies. We are interested in the identification of hazardous regulatory ncRNAs, the identification of these ncRNAs' targets, and the comprehension of the significance of these interactions in the mechanisms behind benzene toxicity. Hence, the focus of recent research is on long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs), and some of the more pertinent articles are also discussed.

ROS-directed activation of Toll/NF-κB in the hematopoietic niche triggers benzene-induced emergency hematopoiesis

Hematopoietic stem cells/progenitor cells (HSC/HPCs) orchestrate the hematopoietic process, effectively regulated by the hematopoietic niche under normal and stressed conditions. The hematopoietic niche provides various soluble factors which influence the differentiation and self-renewal of HSC/HSPs. Unceasing differentiation/proliferation/high metabolic activity of HSC/HPCs makes them susceptible to damage by environmental toxicants like benzene. Oxidative stress, epigenetic modifications, and DNA damage in the HSC/HPCs are the key factors of benzene-induced hematopoietic injury. However, the role of the hematopoietic niche in benzene-induced hematopoietic injury/response is still void. Therefore, the current study aims to unravel the role of the hematopoietic niche in benzene-induced hematotoxicity using a genetically tractable model, Drosophila melanogaster. The lymph gland is a dedicated hematopoietic organ in Drosophila larvae. A group of 30-45 cells called the posterior signaling center (PSC) in the lymph gland acts as a niche that regulates Drosophila HSC/HPCs maintenance. Benzene exposure to Drosophila larvae (48 h) resulted in aberrant hemocyte production, especially hyper-differentiation of lamellocytes followed by premature lymph gland dispersal and reduced adult emergence upon developmental exposure. Subsequent genetic experiments revealed that benzene-induced lamellocyte production and premature lymph gland dispersal were PSC mediated. The genetic experiments further showed that benzene generates Dual oxidase (Duox)-dependent Reactive Oxygen Species (ROS) in the PSC, activating Toll/NF-κB signaling, which is essential for the aberrant hemocyte production, lymph gland dispersal, and larval survival. Together, the study establishes a functional perspective of the hematopoietic niche in a benzene-induced hematopoietic emergency in a genetic model, Drosophila, which might be relevant to higher organisms.

Effects of Benzene: Hematological and Hypersensitivity Manifestations in Resident Living in Oil Refinery Areas

Literature is teeming with publications on industrial pollution. Over the decades, the main industrial pollutants and their effects on human health have been widely framed. Among the various compounds involved, benzene plays a leading role in the onset of specific diseases. Two systems are mainly affected by the adverse health effects of benzene exposure, both acute and chronic: the respiratory and hematopoietic systems. The most suitable population targets for a proper damage assessment on these systems are oil refinery workers and residents near refining plants. Our work fits into this area of interest with the aim of reviewing the most relevant cases published in the literature related to the impairment of the aforementioned systems following benzene exposure. We perform an initial debate between the two clinical branches that see a high epidemiological expression in this slice of the population examined: residents near petroleum refinery areas worldwide. In addition, the discussion expands on highlighting the main immunological implications of benzene exposure, finding a common pathophysiological denominator in inflammation, oxidative stress, and DNA damage, thus helping to set the basis for an increasingly detailed characterization aimed at identifying common molecular patterns between the two clinical fields discussed.

Loss of exosomal LncRNA HCG15 prevents acute myocardial ischemic injury through the NF-κB/p65 and p38 pathways

Exosomes are nanosized bilayer membrane vesicles that may mediate intercellular communication by transporting bioactive molecules, including noncoding RNAs, mRNAs, and proteins. Research has shown that exosomes play an important role in acute myocardial infarction (AMI), but the function and regulation of exosomal long noncoding RNAs (lncRNAs) in AMI are unclear. Thus, RNA sequencing (RNA-Seq) was conducted to investigate the exosomal lncRNA transcriptome from MI patients and identified 65 differentially expressed lncRNAs between the MI and control groups. HCG15, one of the differentially expressed lncRNAs, was verified to have the highest correlation with cTnT by qRT-PCR, and it also contributed to the diagnosis of AMI by receiver operating characteristic (ROC) analysis. Upregulation of HCG15 expression facilitated cardiomyocyte apoptosis and inflammatory cytokine production and inhibited cell proliferation. We also confirmed that HCG15 was mainly wrapped in exosomes from AC16 cardiomyocytes under hypoxia, which contributed to cardiomyocyte apoptosis, the release of inflammatory factors, and inhibition of cell proliferation via the activation of the NF-κB/p65 and p38 pathways, whereas suppressing the expression of HCG15exerted opposite effects, In addition, Overexpression of HCG15 aggravated cardiac IR injury in C57BL/6J mice. This study not only helps elucidate exosomal lncRNA function in AMI pathogenesis but also contributes to the development of novel therapeutic strategies.

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) activates Aryl hydrocarbon receptor (AhR) mediated ROS and NLRP3 inflammasome/p38 MAPK pathway inducing necrosis in cochlear hair cells

Tetrabromodiphenyl ether (BDE-47) is widely used as commercial flame retardants that can be released into the environment and finally enter human body through the food chain. It has been identified to generate neurotoxicity, but little is known about auditory damage and the underlying mechanism following BDE-47 exposure. This study aimed to assess the cell viability with BDE-47 concentration ranging from 0 to 150 μM in mouse organ of Corti-derived cell lines (HEI-OC1). Aryl hydrocarbon receptor (AhR) as an environmental sensor, reactive oxygen species (ROS), NLRP3 inflammasome and p38 MAPK pathways were detected. Results: (1) BDE-47 inhibited the viability in a time- and dose-dependent way in HEI-OC1 cells. Cell cycle was arrested in G1 phase by BDE-47; (2) Elevated intracellular ROS, LDH levels and necrosis were found, which was alleviated by pretreatment with ROS scavenger N-acetylcysteine (NAC); (3) AhR plays an essential role in ligand-regulated transcription factor activation by exogenous environmental compounds. We found increased expression of AhR and decreased downstream targets of CYP 1A1 and CYP 1B1 in BDE-47-treated HEI-OC1 cells, which was reversed by the AhR antagonist CH-223191 for 2 h before BDE-47 exposure. No significant change was detected in CYP 2B; (4) Enhanced expressions of NLRP3 and caspase-1 were induced by BDE-47, with up-regulations of both pro-inflammatory factors for IL-1β, IL-6 and TNF-α, and anti-inflammatory factors for IL-4, IL-10 and IL-13, but down-regulation for IL-1α; (5) Additionally, the p38 MAPK signaling pathway was activated with increased phosphorylation levels of MKK/3/6, p38 MAPK and NF-kB. Overall, our findings illustrate a role of AhR in ROS-induced necrosis of cochlear hair cells by BDE-47 exposure, in which NLRP3 inflammasome and p38 MAPK signaling pathways are activated. The current study first elucidates the sense of hearing damage induced by BDE-47, and cell-specific or mixture exposures in vivo or human studies are needed to confirm this association.

Toxicity in hematopoietic stem cells from bone marrow and peripheral blood in mice after benzene exposure: Single-cell transcriptome sequencing analysis

Benzene is a ubiquitous, occupational, and environmental hematotoxic and leukemogen. Damage to hematopoietic stem cells (HSCs) induced by benzene and its metabolites is a key event in bone marrow (BM) depression and leukemogenesis. There are no reports on transcriptome profiles of HSCs following benzene exposure. Here, Smart-seq2 single-cell transcriptome sequencing was used to detect transcriptomic alternations in BM HSCs and peripheral blood HSCs (PBSCs) in male C57B/6 mice exposed to benzene. We found that benzene caused hematotoxicity which was confirmed by routine blood test, pathological examination, and HSCs percentage analysis. A total of 1514 differentially expressed genes (DEGs) in BM HSCs and 1703 DEGs in PBSCs were screened after treatment with benzene. Weighted gene correlation network analysis revealed that pathways in cancer, transcriptional misregulation in cancer, and hematopoietic cell lineage are vital pathways involved in benzene-induced toxicity in BM HSCs, whereas hematopoietic cell lineage and leukocyte transendothelial migration are critical pathways in PBSCs. Of note, there were 164 common DEGs in both HSCs, out of which 53 genes were co-regulated in both types of HSCs. Subsequent pathway analysis of these 53 genes indicated that the most relevant pathways involved neutrophil degranulation and CD93 localized in the core of the network of the 53 genes, which are known to regulate leukemia stem cell self-renewal and quiescence. Our results could enhance our understanding of HSC responses to benzene, facilitate the identification of potential molecular biomarkers and future studies on its mechanism of toxicity toward HSCs.

Benzene and its effects on cell signaling pathways related to hematopoiesis and leukemia

Benzene is an environmental toxicant found in many consumer products. It is an established human carcinogen and is known to cause acute myeloid leukemia in adults. Epidemiological evidence has since shown that benzene can cross the placenta and affect the fetal liver. Animal studies have shown that in utero exposure to benzene can increase tumor incidence in offspring. Although there have been risk factors established for acute myeloid leukemia, they still do not account for many of the cases. Clearly then, current efforts to elucidate the mechanism by which benzene exerts its carcinogenic properties have been superficial. Owing to the critical role of cell signaling pathways in the development of an organism and its various organ systems, it seems plausible to suspect that these pathways may have a role in leukemogenesis. This review article assesses current evidence of the effects of benzene on critical hematopoietic signaling pathways. Pathways discussed included Hedgehog, Notch/Delta, Wingless/Integrated, nuclear factor-kappaB and others. Following a review of the literature, it seems that current evidence about the effects of benzene on these critical signaling pathways remains limited. Given the important role of these pathways in hematopoiesis, more attention should be given to them.

Co-delivery of p38α MAPK and p65 siRNA by novel liposomal glomerulus-targeting nano carriers for effective immunoglobulin a nephropathy treatment

Glomerulonephritis related renal failure is a frequent cause of end-stage renal disease, and immunoglobulin A nephropathy (IgAN) is the most frequent type of primary glomerulonephritis. As damage induced by IgAN mostly attributes to inflammation responses, inhibiting inflammation in glomerulus can protect normal renal function and delay the onset of renal failure. Hence, reducing levels of p38 MAPK and p65 which are essential regulators in p38 MAPK and NF-κB related inflammation responses could be effective against IgAN. Here, we rationally designed and constructed size- and surface charge- dependent glomerulus-targeting liposomal nanoparticles which are loaded with both p38α MAPK and p65 siRNA. Experiments show that our nanoparticles successfully crossed fenestrated endothelium, accumulated in mesangial cells and endothelial cells, efficiently silenced p38α MAPK and p65 genes, and eventually alleviated proteinuria, inflammation and excessive extracellular matrix deposition in mouse IgAN models. This siRNA co-delivery system thus represents a promising treatment option for IgAN and offers a versatile platform for other glomerular problems. Our work also highlights a novel strategy of glomerulus-targeting and an encouraging therapeutic route for other inflammatory diseases.

Mechanism of Metformin on LPS-Induced Bacterial Myocarditis

Aims:

Metformin is commonly used to treat type 2 diabetes mellitus; however, in recent years, it was found to play a potential role in the protection of myocardial injury. In this study, we intended to investigate whether metformin had protective effects on bacterial myocarditis.

Methods and Results:

We stimulated rat cardiac myoblast H9c2 cells with lipopolysaccharide (LPS) and administrated with metformin. The results showed that cell viability after LPS stimulation was greatly reduced. The expression levels of phosphorylated p38 mitogen-activated protein kinases (MAPK) and c-Jun N-terminal kinases (JNK), nuclear factor (NF)-κB (NF-κB), BAX, and cleaved Caspase3 were significantly increased, while the expression of antiapoptotic protein Bcl-2 showed a prominent decrease compared to control. Nevertheless, the cells activity increased remarkably after metformin administration, and the expression levels of intracellular related proteins showed the opposite trend to that of the LPS group.

Conclusion:

We demonstrate that LPS stimulation may activate intracellular MAPK/JNK and NF-κB signaling pathways and thus induce cell apoptosis. In contrast, metformin reduced apoptosis by inhibiting this signaling pathway and increasing the expression level of Bcl-2. Moreover, it was found that metformin could enhance the ability of cells to antagonize redox damage by regulating the activities of superoxide dismutase and lactate dehydrogenase and subsequently promote the recovery of cardiomyocyte function.

Benzene metabolite hydroquinone promotes DNA homologous recombination repair via the NF-κB pathway

Benzene, a widespread environmental pollutant, induces DNA double-strand breaks (DSBs) and DNA repair, which may further lead to oncogenic mutations, chromosomal rearrangements and leukemogenesis. However, the molecular mechanisms underlying benzene-induced DNA repair and carcinogenesis remain unclear. The human osteosarcoma cell line (U2OS/DR-GFP), which carries a GFP-based homologous recombination (HR) repair reporter, was treated with hydroquinone, one of the major benzene metabolites, to identify the potential effects of benzene on DSB HR repair. RNA-sequencing was further employed to identify the potential key pathway that contributed to benzene-initiated HR repair. We found that treatment with hydroquinone induced a significant increase in HR. NF-κB pathway, which plays a critical role in carcinogenesis in multiple tumors, was significantly activated in cells recovered from hydroquinone treatment. Furthermore, the upregulation of NF-κB by hydroquinone was also found in human hematopoietic stem and progenitor cells. Notably, the inhibition of NF-κB activity by small molecule inhibitors (QNZ and JSH-23) significantly reduced the frequency of hydroquinone-initiated HR (−1.36- and −1.77-fold, respectively, P < 0.01). Our results demonstrate an important role of NF-κB activity in promoting HR repair induced by hydroquinone. This finding sheds light on the underlying mechanisms involved in benzene-induced genomic instability and leukemogenesis and may contribute to the larger exploration of the influence of other environmental pollutants on carcinogenesis.

Benzoquinone induces ROS-dependent mitochondria-mediated apoptosis in HL-60 cells

Benzene exposure affects the hematopoietic system and leads to the occurrence of various types of leukemia and hematotoxicity. It has been confirmed that active metabolites of benzene, including 1,4-benzoquinone (1,4-BQ), can induce reactive oxygen species (ROS) and apoptosis in the bone marrow, and recent studies have also suggested that benzene exposure can affect mitochondrial function in both experimental animals and cell lines. However, the potential relationship among ROS production, mitochondrial damages, and subsequent apoptosis following benzene exposure has not been well studied in detail. In the present study, we utilized HL-60 cells, a well-characterized human myeloid cell line, as an in vitro model and examined the effects of 1,4-BQ on intracellular ROS formation, mitochondria damage, and the occurrence of apoptotic events with or without using the ROS scavenger N-acetyl-l-cysteine (NAC). The results demonstrated that 1,4-BQ could dose-dependently induce production of ROS and mitochondrial damage as characterized by mitochondrial membrane potential disruption, mitochondrial ultrastructure alteration, and induced apoptosis and activated caspase-3 and caspase-9. Preincubation of HL-60 cells with NAC prior to 1,4-BQ treatment could block 1,4-BQ-induced production of ROS and the occurrence of apoptosis. These results demonstrated that 1,4-BQ induced apoptosis in HL-60 cells through a ROS-dependent mitochondrial-mediated pathway.

Febuxostat Modulates MAPK/NF-κBp65/TNF-α Signaling in Cardiac Ischemia-Reperfusion Injury

Xanthine oxidase and xanthine dehydrogenase have been implicated in producing myocardial damage following reperfusion of an occluded coronary artery. We investigated and compared the effect of febuxostat and allopurinol in an experimental model of ischemia-reperfusion (IR) injury with a focus on the signaling pathways involved. Male Wistar rats were orally administered vehicle (CMC) once daily (sham and IR + control), febuxostat (10 mg/kg/day; FEB10 + IR), or allopurinol (100 mg/kg/day; ALL100 + IR) for 14 days. On the 15th day, the IR-control and treatment groups were subjected to one-stage left anterior descending (LAD) coronary artery ligation for 45 minutes followed by a 60-minute reperfusion. Febuxostat and allopurinol pretreatment significantly improved cardiac function and maintained morphological alterations. They also attenuated oxidative stress and apoptosis by suppressing the expression of proapoptotic proteins (Bax and caspase-3), reducing TUNEL-positive cells, and increasing the level of antiapoptotic proteins (Bcl-2). The MAPK-based molecular mechanism revealed suppression of active JNK and p38 proteins concomitant with the rise in ERK1/ERK2, a prosurvival kinase. Additionally, a reduction in the level of inflammatory markers (TNF-α, IL-6, and NF-κB) was also observed. The changes observed with febuxostat were remarkable in comparison with those observed with allopurinol. Febuxostat protects relatively better against IR injury than allopurinol by suppressing inflammation and apoptosis mediating the MAPK/NF-κBp65/TNF-α pathway.

Inhibition of NF-κB activation improves insulin resistance of L6 cells

To explore the role of NF-κB activation in the development of insulin resistance and investigate whether or not that the inhibition of NF-κB activation by PDTC will improve the insulin resistance of L6 cells exposed to H₂O₂. L6 cells were treated with H₂O₂, PDTC or both H₂O₂ and PDTC for 4 hours. The uptake of glucose with stimulation of insulin, the expression of P38-MAPK, p- P38-MAPK, NF-κBp65, p- NF-κBp65, IRS-1, IRS-2, p-IRS-2, PI3K, IκBα, p- IκBα, caspase-8 and GLUT4, the production of ROS, TNF-α, IL-6 and IL-1β as well as the apoptosis rate of L6 cells were determined and compared in L6 treated with H₂O₂ alone or both H₂O₂ and PDTC. Compared with the L6 cells treated with H₂O₂ alone, the L6 cells treated with both H₂O₂ and PDTC showed (1) significantly lower production of ROS, TNF-α, IL-6 and IL-1β; (2) significantly decreased expression of P38-MAPK, p- P38-MAPK and NF-κBp65, p- NF-κBp65, p- IκBα and caspase-8; (3) significantly lower rate of apoptosis; (4) significantly higher expression of IRS-2, p-IRS-2 (Tyr 612), PI3K and GLUT4; (5) significantly higher uptake of glucose with stimulation of insulin; (6) significantly increased expression of Bcl2 and decreased ratio of Bax to Bcl2. Based on the findings of the present study, inhibition of NF-κB activation by PDTC would improve the insulin resistance of L6 cells exposed to H₂O₂.

Occupational exposure to carcinogens: Benzene, pesticides and fibers (Review)

It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as 'probable' and 'possible' human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities.

Valproic acid exposure decreases Cbp/p300 protein expression and histone acetyltransferase activity in P19 cells

The teratogenicity of the antiepileptic drug valproic acid (VPA) is well established and its inhibition of histone deacetylases (HDAC) is proposed as an initiating factor. Recently, VPA-mediated HDAC inhibition was demonstrated to involve transcriptional downregulation of histone acetyltransferases (HATs), which was proposed to compensate for the increased acetylation resulting from HDAC inhibition. Cbp and p300 are HATs required for embryonic development and deficiencies in either are associated with congenital malformations and embryolethality. The objective of the present study was to characterize Cbp/p300 following VPA exposure in P19 cells. Consistent with previous studies, exposure to 5mM VPA over 24h induced a moderate decrease in Cbp/p300 mRNA, which preceded a strong decrease in total cellular protein mediated by ubiquitin-proteasome degradation. Nuclear Cbp/p300 protein was also decreased following VPA exposure, although to a lesser extent. Total cellular and nuclear p300 HAT activity was reduced proportionately to p300 protein levels, however while total cellular HAT activity also decreased, nuclear HAT activity was unaffected. Using the Cbp/p300 HAT inhibitor C646, we demonstrated that HAT inhibition similarly affected many of the same endpoints as VPA, including increased reactive oxygen species and caspase-3 cleavage, the latter of which could be attenuated by pre-treatment with the antioxidant catalase. C646 exposure also decreased NF-κB/p65 protein, which was not due to reduced mRNA and was not attenuated with catalase pre-treatment. This study provides support for an adaptive HAT response following VPA exposure and suggests that reduced Cbp/p300 HAT activity could contribute to VPA-mediated alterations.

Gypenoside Protects Cardiomyocytes against Ischemia-Reperfusion Injury via the Inhibition of Mitogen-Activated Protein Kinase Mediated Nuclear Factor Kappa B Pathway In Vitro and In Vivo

Gypenoside (GP) is the major effective component of Gynostemma pentaphyllum and has been shown to encompass a variety of pharmacological activities. In this study, we investigated whether GP is able to protect cardiomyocytes against injury myocardial ischemia-reperfusion (I/R) injury by using in vitro oxygen-glucose deprivation-reoxygenation (OGD/R) H9c2 cell model and in vivo myocardial I/R rat model. We found that GP pre-treatment alleviated the impairments on the cardiac structure and function in I/R injured rats. Moreover, pre-treatment with GP significantly inhibited IκB-α phosphorylation and nuclear factor (NF)-κB p65 subunit translocation into nuclei. GP and the MAPK pathway inhibitors also reduced the phosphorylation of ERK, JNK, and p38 in vitro. Specific inhibition of ERK, JNK, and p38 increased the cell viability of OGD/R injured cells. Taken together, our data demonstrated that GP protects cardiomyocytes against I/R injury by inhibiting NF-κB p65 activation via the MAPK signaling pathway both in vitro and in vivo. These findings suggest that GP may be a promising agent for the prevention or treatment of myocardial I/R injury.

Tetrachlorobenzoquinone exhibits neurotoxicity by inducing inflammatory responses through ROS-mediated IKK/IκB/NF-κB signaling

Tetrachlorobenzoquinone (TCBQ) is a joint metabolite of persistent organic pollutants (POPs), hexachlorobenzene (HCB) and pentachlorophenol (PCP). Previous studies have been reported that TCBQ contributes to acute hepatic damage due to its pro-oxidative nature. In the current study, TCBQ showed the highest capacity on the cytotoxicity, ROS formation and inflammatory cytokines release among four compounds, i.e., HCB, PCP, tetrachlorohydroquinone (TCHQ, reduced form of TCBQ) and TCBQ, in PC 12 cells. Further mechanistic study illustrated TCBQ activates nuclear factor-kappa B (NF-κB) signaling. The activation of NF-κB was identified by measuring the protein expressions of inhibitor of nuclear factor kappa-B kinase (IKK) α/β, p-IKKα/β, an inhibitor of NF-κB (IκB) α, p-IκBα, NF-κB (p65) and p-p65. The translocation of NF-κB was assessed by Western blotting of p65 in nuclear/cytosolic fractions, electrophoretic mobility shift assay (EMSA) and luciferase reporter gene assay. In addition, TCBQ significantly induced protein and mRNA expressions of inflammatory cytokines and mediators, such as interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and the production of nitric oxide (NO) and prostaglandin E2 (PGE2). Pyrrolidine dithiocarbamate (PDTC), a specific NF-κB inhibitor inhibited these effects efficiently, further suggested TCBQ-induced inflammatory responses involve NF-κB signaling. Moreover, antioxidants, i.e., N-acetyl-l-cysteine (NAC), Vitamin E and curcumin, ameliorated TCBQ-induced ROS generation as well as the activation of NF-κB, which implied that ROS serve as the upstream molecule of NF-κB signaling. In summary, TCBQ exhibits a neurotoxic effect by inducing oxidative stress-mediated inflammatory responses via the activation of IKK/IκB/NF-κB pathway in PC12 cells.

Parental, In Utero, and Early-Life Exposure to Benzene and the Risk of Childhood Leukemia: A Meta-Analysis

Benzene is an established cause of adult leukemia, but whether it is associated with childhood leukemia remains unclear. We conducted a meta-analysis in which we reviewed the epidemiologic literature on this topic and explored causal inference, bias, and heterogeneity. The exposure metrics that we evaluated included occupational and household use of benzenes and solvents, traffic density, and traffic-related air pollution. For studies of occupational and household product exposure published from 1987 to 2014, the summary relative risk for childhood leukemia was 1.96 (95% confidence interval (CI): 1.53, 2.52; n = 20). In these studies, the summary relative risk was higher for acute myeloid leukemia (summary relative risk (sRR) = 2.34, 95% CI: 1.72, 3.18; n = 6) than for acute lymphoblastic leukemia (sRR = 1.57; 95% CI: 1.21, 2.05; n = 14). The summary relative risk was higher for maternal versus paternal exposure, in studies that assessed benzene versus all solvents, and in studies of gestational exposure. In studies of traffic density or traffic-related air pollution published from 1999 to 2014, the summary relative risk was 1.48 (95% CI: 1.10, 1.99; n = 12); it was higher for acute myeloid leukemia (sRR = 2.07; 95% CI: 1.34, 3.20) than for acute lymphoblastic leukemia (sRR = 1.49; 95% CI: 1.07, 2.08) and in studies that involved detailed models of traffic pollution (sRR = 1.70; 95% CI: 1.16, 2.49). Overall, we identified evidence of associations between childhood leukemia and several different potential metrics of benzene exposure.

1,4-benzoquinone-induced STAT-3 hypomethylation in AHH-1 cells: Role of oxidative stress

Benzene, a known occupational and environmental contaminant, is associated with increased risk of leukemia. The objectives of this study were to elucidate the regulatory mechanism of the hypomethylated STAT3 involved in benzene toxicity in vitro. As 1,4-benzoquinone (1,4-BQ) is one of benzene’s major toxic metabolites, AHH-1 cells were treated by 1,4-BQ for 24 h with or without pretreatment of the antioxidant a-LA or the methyltransferase inhibitor, 5-aza-2′ deoxycytidine (5-aza). The cell viability was investigated using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. ROS was determined via 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) flow cytometric assays. The level of oxidative stress marker 8-OHdG was measured by enzyme-linked immunosorbent assay. Methylation-specific PCR was used to detect the methylation status of STAT3. Results indicated the significantly increasing expression of ROS and 8-OHdG which accompanied with STAT3 hypomethylation in 1,4-BQ-treated AHH-1 cells. α-LA suppressed the expression of both ROS and 8-OHdG, simultaneously reversed 1,4-BQ-induced STAT3 hypomethylation. However, although the methylation inhibitor, 5-aza reduced the expression level of ROS and 8-OHdG, but had no obvious inhibiting effect on STAT3 methylation level. Taken together, oxidative stress are involved 1,4-BQ-induced STAT3 methylation expression.

Back to the future: transgenerational transmission of xenobiotic-induced epigenetic remodeling

Epigenetics, or regulation of gene expression independent of DNA sequence, is the missing link between genotype and phenotype. Epigenetic memory, mediated by histone and DNA modifications, is controlled by a set of specialized enzymes, metabolite availability, and signaling pathways. A mostly unstudied subject is how sub-toxic exposure to several xenobiotics during specific developmental stages can alter the epigenome and contribute to the development of disease phenotypes later in life. Furthermore, it has been shown that exposure to low-dose xenobiotics can also result in further epigenetic remodeling in the germ line and contribute to increase disease risk in the next generation (multigenerational and transgenerational effects). We here offer a perspective on current but still incomplete knowledge of xenobiotic-induced epigenetic alterations, and their possible transgenerational transmission. We also propose several molecular mechanisms by which the epigenetic landscape may be altered by environmental xenobiotics and hypothesize how diet and physical activity may counteract epigenetic alterations.

Ginsenoside Rb3 protects cardiomyocytes against ischemia-reperfusion injury via the inhibition of JNK-mediated NF-κB pathway: a mouse cardiomyocyte model

Ginsenoside Rb3 is extracted from the plant Panax ginseng and plays important roles in cardiovascular diseases, including myocardial ischemia-reperfusion (I/R) injury. NF-κB is an important transcription factor involved in I/R injury. However, the underlying mechanism of ginsenoside Rb3 in myocardial I/R injury remains poorly understood. In the current study, a model of myocardial I/R injury was induced via oxygen and glucose deprivation (OGD) followed by reperfusion (OGD-Rep) in mouse cardiac myoblast H9c2 cells. Our data demonstrate that ginsenoside Rb3 suppresses OGD-Rep-induced cell apoptosis by the suppression of ROS generation. By detecting the NF-κB signaling pathway, we discover that the protective effect of ginsenoside Rb3 on the OGD-Rep injury is closely related to the inhibition of NF-κB activity. Ginsenoside Rb3 inhibits the upregulation of phospho-IκB-α and nuclear translocation of NF-κB subunit p65 which are induced by ORD-Rep injury. In addition, the extract also inhibits the OGD-Rep-induced increase in the expression of inflammation-related factors, such as IL-6, TNF-α, monocyte chemotactic protein-1 (MCP-1), MMP-2 and MMP-9. However, LPS treatment alleviates the protective roles of ginsenoside Rb3 and activates the NF-κB pathway. Finally, the upstream factors of NF-κB were analyzed, including the Akt/Foxo3a and MAPK signaling pathways. We find that ginsenoside Rb3 pretreatment only decreases the phosphorylation of JNK induced by OGD-Rep injury, an indicator of the MAPK pathway. Importantly, an inhibitor of phospho-JNK, SP600125, protects against OGD-Rep induced apoptosis and inhibited NF-κB signaling pathway, similar to the roles of ginsenoside Rb3. Taken together, our results demonstrate that the protective effect of ginsenoside Rb3 on the OGD-Rep injury is attributed to the inhibition of JNK-mediated NF-κB activation, suggesting that ginsenoside Rb3 has the potential to serve as a novel therapeutic agent for myocardial I/R injury.