The role of metabolism in cellular quiescence.

Cellular quiescence is a dormant, non-dividing cell state characterized by significant shifts in physiology and metabolism. Quiescence plays essential roles in a wide variety of biological processes, ranging from microbial sporulation to human reproduction and wound repair. Moreover, when the regulation of quiescence is disrupted, it can drive cancer growth and compromise tissue regeneration after injury. In this Review, we examine the dynamic changes in metabolism that drive and support dormant and transiently quiescent cells, including spores, oocytes and adult stem cells. We begin by defining quiescent cells and discussing their roles in key biological processes. We then examine metabolic factors that influence cellular quiescence in both healthy and disease contexts, and how these could be leveraged in the treatment of cancer.

LncRNA CARMN inhibits abdominal aortic aneurysm formation and vascular smooth muscle cell phenotypic transformation by interacting with SRF.

Phenotypic transformation of vascular smooth muscle cells (VSMCs) plays a crucial role in abdominal aortic aneurysm (AAA) formation. CARMN, a highly conserved, VSMC-enriched long noncoding RNA (lncRNA), is integral in orchestrating various vascular pathologies by modulating the phenotypic dynamics of VSMCs. The influence of CARMN on AAA formation, particularly its mechanisms, remains enigmatic. Our research, employing single-cell and bulk RNA sequencing, has uncovered a significant suppression of CARMN in AAA specimens, which correlates strongly with the contractile function of VSMCs. This reduced expression of CARMN was consistent in both 7- and 14-day porcine pancreatic elastase (PPE)-induced mouse models of AAA and in human clinical cases. Functional analyses disclosed that the diminution of CARMN exacerbated PPE-precipitated AAA formation, whereas its augmentation conferred protection against such formation. Mechanistically, we found CARMN's capacity to bind with SRF, thereby amplifying its role in driving the transcription of VSMC marker genes. In addition, our findings indicate an enhancement in CAMRN transcription, facilitated by the binding of NRF2 to its promoter region. Our study indicated that CARMN plays a protective role in preventing AAA formation and restrains the phenotypic transformation of VSMC through its interaction with SRF. Additionally, we observed that the expression of CARMN is augmented by NRF2 binding to its promoter region. These findings suggest the potential of CARMN as a viable therapeutic target in the treatment of AAA.

Nanoplastics causes heart aging/myocardial cell senescence through the Ca2+/mtDNA/cGAS-STING signaling cascade.

BACKGROUND: Nanoplastics (NPs) are now a new class of pollutants widely present in the soil, atmosphere, freshwater and marine environments. Nanoplastics can rapidly penetrate cell membranes and accumulate in human tissues and organs, thus posing a potential threat to human health. The heart is the main power source of the body. But up to now, the toxicological effects of long-term exposure to nanoplastics on the heart has not been revealed yet. RESULTS: We evaluated the effects of long term exposure of nanoplastics on cardiac cell/tissue in vitro and in vivo model. Furthermore, we explored the molecular mechanism by which nanoplastics exposure causes myocardial cell senescence. Immunohistochemistry, indirect immunofluorescence and ELISA were performed to detect the effects of nanoplastics on heart aging. We found that nanoplastics were able to induce significant cardiac aging through a series of biochemical assays in vivo. In vitro, the effects of nanoplastics on cardiac cell were investigated, and found that nanoplastics were able to internalize into cardiomyocytes in time and dose-dependant manner. Further biochemical analysis showed that nanoplastics induces cardiomyocytes senescence by detecting a series of senescence marker molecules. Molecular mechanism research shows that nanoplastics may cause mitochondrial destabilization by inducing oxidative stress, which leads to the leakage of mtDNA from mitochondria into the cytoplasm, and then cytoplasm-localized mt-DNA activates the cGAS-STING signaling pathway and promotes inflammation response, ultimately inducing cardiomyocytes senescence. CONCLUSIONS: In this work, we found that nanoplastics exposure induces premature aging of heart. Current research also reveals the molecular mechanism by which nanoplastics induces cardiomyocyte senescence. This study laid the foundation for further studying the potential harm of nanoplastics exposure on heart.

HDAC Inhibitors Alleviate Uric Acid-Induced Vascular Endothelial Cell Injury by Way of the HDAC6/FGF21/PI3K/AKT Pathway.

ABSTRACT: Uric acid (UA) accumulation triggers endothelial dysfunction, oxidative stress, and inflammation. Histone deacetylase (HDAC) plays a vital role in regulating the pathological processes of various diseases. However, the influence of HDAC inhibitor on UA-induced vascular endothelial cell injury (VECI) remains undefined. Hence, this study aimed to investigate the effect of HDACs inhibition on UA-induced vascular endothelial cell dysfunction and its detailed mechanism. UA was used to induce human umbilical vein endothelial cell (HUVEC) injury. Meanwhile, potassium oxonate-induced and hypoxanthine-induced hyperuricemia mouse models were also constructed. A broad-spectrum HDAC inhibitor trichostatin A (TSA) or selective HDAC6 inhibitor TubastatinA (TubA) was given to HUVECs or mice to determine whether HDACs can affect UA-induced VECI. The results showed pretreatment of HUVECs with TSA or HDAC6 knockdown-attenuated UA-induced VECI and increased FGF21 expression and phosphorylation of AKT, eNOS, and FoxO3a. These effects could be reversed by FGF21 knockdown. In vivo, both TSA and TubA reduced inflammation and tissue injury while increased FGF21 expression and phosphorylation of AKT, eNOS, and FoxO3a in the aortic and renal tissues of hyperuricemia mice. Therefore, HDACs, especially HDAC6 inhibitor, alleviated UA-induced VECI through upregulating FGF21 expression and then activating the PI3K/AKT pathway. This suggests that HDAC6 may serve as a novel therapeutic target for treating UA-induced endothelial dysfunction.

Successful management of camrelizumab-induced immune-checkpoint-inhibitors-related myocarditis.

INTRODUCTION: Immune checkpoint inhibitors can cause immune-related toxicity in various systems, with myocarditis being the most severe and life-threatening manifestation. This report presents a case in which myocarditis developed following administration of programmed cell death protein-1 (PD-1) inhibitors therapy. We describe the diagnosis and treatment of this patient in detail. CASE REPORT: We present the case of a 59-year-old female diagnosed with post-operative esophageal cancer and hepatic metastases. The patient underwent second-line treatment with domestically-made PD-1 inhibitor, camrelizumab, in combination with paclitaxel (albumin-bound) and carboplatin for two cycles. During the course of treatment, an electrocardiogram (ECG) revealed ST segment elevation in leads II, III, aVF, V2, V3, and V4, along with T wave changes in leads I and aVL. Laboratory examinations showed abnormal levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT). Despite the absence of clinical symptoms, the patient was routinely hospitalized three weeks later. Based on the findings from the ECG, cardiac biomarkers, echocardiography, echocardiogram, cardiac magnetic resonance, and angiography, she was diagnosed with immune-checkpoint-inhibitors-related myocarditis. MANAGEMENT AND OUTCOME: The patient received immunoglobulin (0.5 g/kg/day) and was initially given methylprednisolone (1000 mg/day). Methylprednisolone was gradually reduced to 40 mg/day in 2 weeks. During this time, the levels of biomarkers indicative of myocardial injury also exhibited a simultaneous decline. DISCUSSION: This case highlights the importance of early detection and prompt intervention, including initiating appropriate steroid therapy and discontinuing of immune checkpoint inhibitors. Such measures can effectively prevent morbidity and mortality, ultimately leading to an improved prognosis.

G9a coordinates with the RPA complex to promote DNA damage repair and cell survival.

Histone methyltransferase G9a has critical roles in promoting cancer-cell growth and gene suppression, but whether it is also associated with the DNA damage response is rarely studied. Here, we report that loss of G9a impairs DNA damage repair and enhances the sensitivity of cancer cells to radiation and chemotherapeutics. In response to DNA double-strand breaks (DSBs), G9a is phosphorylated at serine 211 by casein kinase 2 (CK2) and recruited to chromatin. The chromatin-enriched G9a can then directly interact with replication protein A (RPA) and promote loading of the RPA and Rad51 recombinase to DSBs. This mechanism facilitates homologous recombination (HR) and cell survival. We confirmed the interaction between RPA and G9a to be critical for RPA foci formation and HR upon DNA damage. Collectively, our findings demonstrate a regulatory pathway based on CK2-G9a-RPA that permits HR in cancer cells and provide further rationale for the use of G9a inhibitors as a cancer therapeutic.

Genetically Encoded FapR-NLuc as a Biosensor to Determine Malonyl-CoA in Situ at Subcellular Scales.

Malonyl-CoA is one of the key metabolic intermediates in fatty acid metabolism as well as a key player in protein post-translational modifications. Detection of malonyl-CoA in live cells is challenging because of the lack of effective measuring tools. Here we developed a genetically encoded biosensor, FapR-NLuc, by combining a malonyl-CoA responsive bacterial transcriptional factor, FapR, with an engineered luciferase, NanoLuciferase (NLuc). FapR-NLuc specifically responds to malonyl-CoA and enables the rapid detection of malonyl-CoA at the micromolar level. More importantly, it is reflective of the fluctuations of malonyl-CoA in live cells. Upon being targeted to subcellular compartments, this biosensor can detect the changes of malonyl-CoA in situ within organelles. Thus, FapR-NLuc can potentially be used as a tool to study the kinetics of malonyl-CoA in live cells, which will shed light on the underlying mechanisms of malonyl-CoA-mediated biological processes.

Tissue distribution, subcellular localization, and enzymatic activity analysis of human SIRT5 isoforms.

SIRT5 is one of the seven mammalian sirtuins which are NAD+-dependent deacylases. In human beings, SIRT5 gene encodes for four SIRT5 protein isoforms, namely SIRT5iso1, SIRT5iso2, SIRT5iso3, and SIRT5iso4. Previous studies have focused mostly on SIRT5iso1. Characteristics regarding localization, activity and tissue distribution of the other three SIRT5 isoforms remain unclear. In the present study, we characterized these properties of these SIRT5 isoforms. We found that SIRT5iso1-3 were mitochondria-localized, while SIRT5iso4 localized mainly in cytoplasm. SIRT5iso2-4 had little deacylase activity comparing with SIRT5iso1. Although cDNAs of all SIRT5 isoforms were readily detected in multiply tissues according to EST database, proteins of SIRT5iso2-4 were seldom observed in human cell lines. Altogether, we dissected the four isoforms of human SIRT5 protein.

Cardiovascular benefits of short-term indoor air filtration intervention in elderly living in Beijing: An extended analysis of BIAPSY study.

BACKGROUND: Adverse cardiovascular effects associated with air pollution exposure have been widely demonstrated. However, inconsistent cardiovascular responses were observed from reducing indoor air pollution exposure. We aimed to assess whether short-term air filtration intervention could benefit cardiovascular health in elderly living in high pollution area. METHODS: A randomized crossover intervention study of short-term indoor air filtration intervention on cardiovascular health was conducted among 35 non-smoking elderly participants living in Beijing in the winter of 2013, as part of Beijing Indoor Air Purifier StudY (BIAPSY). Portable air filtration units were randomly allocated to active filtration for 2 weeks and sham filtration for 2 weeks in the households. Twelve-hour daytime ambulatory heart rate variability (HRV) and blood pressure (ABP) were measured during active and sham filtration. Concurrently, real-time indoor and outdoor particulate matter with diameter less than 2.5 µm (PM2.5) and indoor black carbon (BC) concentrations were measured. We applied generalized additive mixed models to evaluate the associations of 1- to 10-h moving average (MA) exposures of indoor PM2.5 and BC with HRV and ABP indices, and to explore whether these associations could be modified by air filtration. RESULTS: We observed decreases of 34.8% in indoor PM2.5 and 35.3% in indoor BC concentrations during active filtration. Indoor PM2.5 and BC exposures were significantly associated with reduced HRV and increased ABP indices, and greater changes were observed during sham filtration. In specific, each 10 µg/m3 increase in indoor PM2.5 at MA8-h was associated with a significant reduction of 1.34% (95% CI: -2.42, -0.26) in SDNN during sham filtration, compared with a non-significant reduction of 0.81% (95% CI: -6.00, 4.68) during active filtration (Pinter< 0.001). Each 1 µg/m3 increase in indoor BC at MA8-h was associated with a significant increase of 2.41% (95% CI: 0.38, 4.47) in SBP during sham filtration, compared with a non-significant increase of -1.09% (95% CI: -4.06, 1.96) during active filtration (Pinter = 0.135). Nonlinear inverse exposure-response relationships of indoor air pollution exposures with predicted HRV and ABP indices also confirmed some cardiovascular benefits of short-term air filtration intervention. CONCLUSIONS: Our results suggested that short-term indoor air filtration intervention can be of some cardiovascular benefits in elderly living with high pollution episodes.

Lysine malonylation is elevated in type 2 diabetic mouse models and enriched in metabolic associated proteins.

Protein lysine malonylation, a newly identified protein post-translational modification (PTM), has been proved to be evolutionarily conserved and is present in both eukaryotic and prokaryotic cells. However, its potential roles associated with human diseases remain largely unknown. In the present study, we observed an elevated lysine malonylation in a screening of seven lysine acylations in liver tissues of db/db mice, which is a typical model of type 2 diabetes. We also detected an elevated lysine malonylation in ob/ob mice, which is another model of type 2 diabetes. We then performed affinity enrichment coupled with proteomic analysis on liver tissues of both wild-type (wt) and db/db mice and identified a total of 573 malonylated lysine sites from 268 proteins. There were more malonylated lysine sites and proteins in db/db than in wt mice. Five proteins with elevated malonylation were verified by immunoprecipitation coupled with Western blot analysis. Bioinformatic analysis of the proteomic results revealed the enrichment of malonylated proteins in metabolic pathways, especially those involved in glucose and fatty acid metabolism. In addition, the biological role of lysine malonylation was validated in an enzyme of the glycolysis pathway. Together, our findings support a potential role of protein lysine malonylation in type 2 diabetes with possible implications for its therapy in the future.

Prediction of Protein Lysine Acylation by Integrating Primary Sequence Information with Multiple Functional Features.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic methods have been widely used to identify lysine acylation proteins. However, these experimental approaches often fail to detect proteins that are in low abundance or absent in specific biological samples. To circumvent these problems, we developed a computational method to predict lysine acylation, including acetylation, malonylation, succinylation, and glutarylation. The prediction algorithm integrated flanking primary sequence determinants and evolutionary conservation of acylated lysine as well as multiple protein functional annotation features including gene ontology, conserved domains, and protein-protein interactions. The inclusion of functional annotation features increases predictive power oversimple sequence considerations for four of the acylation species evaluated. For example, the Matthews correlation coefficient (MCC) for the prediction of malonylation increased from 0.26 to 0.73. The performance of prediction was validated against an independent data set for malonylation. Likewise, when tested with independent data sets, the algorithm displayed improved sensitivity and specificity over existing methods. Experimental validation by Western blot experiments and LC-MS/MS detection further attested to the performance of prediction. We then applied our algorithm on to the mouse proteome and reported the global-scale prediction of lysine acetylation, malonylation, succinylation, and glutarylation, which should serve as a valuable resource for future functional studies.

SET7/9 regulates cancer cell proliferation by influencing ß-catenin stability.

ß-Catenin, which is a key mediator of the wingless-integration site (Wnt)/ß-catenin signaling pathway, plays an important role in cell proliferation, cell fate determination, and tumorigenesis, by regulating the expression of a wide range of target genes. Although a variety of posttranslational modifications are involved in ß-catenin activity, the role of lysine methylation in ß-catenin activity is largely unknown. In this study, su(var)3-9, enhancer-of-zeste, trithorax (SET) domain-containing protein 7 (SET7/9), a lysine methyltransferase, interacted with and methylated ß-catenin, as demonstrated both in vitro and in vivo. The interaction and methylation were significantly enhanced in response to H2O2 stimulation. A mutagenesis assay and mass spectrometric analyses revealed that ß-catenin was monomethylated by SET7/9 at lysine residue 180. Methylated ß-catenin was easily recognized by phosphokinase glycogen synthase kinase (GSK)-3ß for degradation. Consistent with this finding, the mutated ß-catenin (K180R) that cannot be methylated exhibited a longer half-life than did the methylated ß-catenin. The consequent depletion of SET7/9 by shRNA or the mutation of the ß-catenin (K180R) significantly enhanced the expression of Wnt/ß-catenin target genes such as c-myc and cyclin D1 and promoted the growth of cancer cells. Together, these results provide a novel mechanism by which Wnt/ß-catenin signaling is regulated in response to oxidative stress.

Methylation of SUV39H1 by SET7/9 results in heterochromatin relaxation and genome instability.

Suppressor of variegation 3-9 homolog 1 (SUV39H1), a histone methyltransferase, catalyzes histone 3 lysine 9 trimethylation and is involved in heterochromatin organization and genome stability. However, the mechanism for regulation of the enzymatic activity of SUV39H1 in cancer cells is not yet well known. In this study, we identified SET domain-containing protein 7 (SET7/9), a protein methyltransferase, as a unique regulator of SUV39H1 activity. In response to treatment with adriamycin, a DNA damage inducer, SET7/9 interacted with SUV39H1 in vivo, and a GST pull-down assay confirmed that the chromodomain-containing region of SUV39H1 bound to SET7/9. Western blot using antibodies specific for antimethylated SUV39H1 and mass spectrometry demonstrated that SUV39H1 was specifically methylated at lysines 105 and 123 by SET7/9. Although the half-life and localization of methylated SUV39H1 were not noticeably changed, the methyltransferase activity of SUV39H1 was dramatically down-regulated when SUV39H1 was methylated by SET7/9. Consequently, H3K9 trimethylation in the heterochromatin decreased significantly, which, in turn, led to a significant increase in the expression of satellite 2 (Sat2) and α-satellite (α-Sat), indicators of heterochromatin relaxation. Furthermore, a micrococcal nuclease sensitivity assay and an immunofluorescence assay demonstrated that methylation of SUV39H1 facilitated genome instability and ultimately inhibited cell proliferation. Together, our data reveal a unique interplay between SET7/9 and SUV39H1--two histone methyltransferases--that results in heterochromatin relaxation and genome instability in response to DNA damage in cancer cells.

Identification and Bioactivity of Compounds from the Mangrove Endophytic Fungus Alternaria sp.

Racemic new cyclohexenone and cyclopentenone derivatives, (±)-(4R*,5S*,6S*)-3-amino-4,5,6-trihydroxy-2-methoxy-5-methyl-2-cyclohexen-1-one (1) and (±)-(4S*,5S*)-2,4,5-trihydroxy-3-methoxy-4-methoxycarbonyl-5-methyl-2-cyclopenten-1-one (2), and two new xanthone derivatives 4-chloro-1,5-dihydroxy-3-hydroxymethyl-6-methoxycarbonyl-xanthen-9-one (3) and 2,8-dimethoxy-1,6-dimethoxycarbonyl-xanthen-9-one (4), along with one known compound, fischexanthone (5), were isolated from the culture of the mangrove endophytic fungus Alternaria sp. R6. The structures of these compounds were elucidated by analysis of their MS (Mass), one and two dimensional NMR (nuclear magnetic resonance) spectroscopic data. Compounds 1 and 2 exhibited potent ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] scavenging activities with EC50 values of 8.19 ± 0.15 and 16.09 ± 0.01 µM, respectively. In comparison to Triadimefon, compounds 2 and 3 exhibited inhibitory activities against Fusarium graminearum with minimal inhibitory concentration (MIC) values of 215.52 and 107.14 µM, respectively, and compound 3 exhibited antifungal activity against Calletotrichum musae with MIC value of 214.29 µM.

Characterization and prediction of lysine (K)-acetyl-transferase specific acetylation sites.

Lysine acetylation is a well-studied post-translational modification on both histone and nonhistone proteins. More than 2000 acetylated proteins and 4000 lysine acetylation sites have been identified by large scale mass spectrometry or traditional experimental methods. Although over 20 lysine (K)-acetyl-transferases (KATs) have been characterized, which KAT is responsible for a given protein or lysine site acetylation is mostly unknown. In this work, we collected KAT-specific acetylation sites manually and analyzed sequence features surrounding the acetylated lysine of substrates from three main KAT families (CBP/p300, GCN5/PCAF, and the MYST family). We found that each of the three KAT families acetylates lysines with different sequence features. Based on these differences, we developed a computer program, Acetylation Set Enrichment Based method to predict which KAT-families are responsible for acetylation of a given protein or lysine site. Finally, we evaluated the efficiency of our method, and experimentally detected four proteins that were predicted to be acetylated by two KAT families when one representative member of the KAT family is over expressed. We conclude that our approach, combined with more traditional experimental methods, may be useful for identifying KAT families responsible for acetylated substrates proteome-wide.

ASEB: a web server for KAT-specific acetylation site prediction.

Protein lysine acetylation plays an important role in the normal functioning of cells, including gene expression regulation, protein stability and metabolism regulation. Although large amounts of lysine acetylation sites have been identified via large-scale mass spectrometry or traditional experimental methods, the lysine (K)-acetyl-transferase (KAT) responsible for the acetylation of a given protein or lysine site remains largely unknown due to the experimental limitations of KAT substrate identification. Hence, the in silico prediction of KAT-specific acetylation sites may provide direction for further experiments. In our previous study, we developed the acetylation set enrichment based (ASEB) computer program to predict which KAT-families are responsible for the acetylation of a given protein or lysine site. In this article, we provide KAT-specific acetylation site prediction as a web service. This web server not only provides the online tool and R package for the method in our previous study, but several useful services are also included, such as the integration of protein-protein interaction information to enhance prediction accuracy. This web server can be freely accessed at http://cmbi.bjmu.edu.cn/huac.

[Preparation of metagenomic DNA from bronchoalveolar lavage fluids of patients with chronic obstructive pulmonary diseases].

OBJECTIVE: To optimize the method of isolating a small amount of metagenomic DNA efficiently from bronchoalveolar lavage fluids (BALF) of patients with stable chronic obstructive pulmonary diseases (COPD) , which will facilitate subsequent PCR and DNA sequencing. METHODS: BALF (5mL) of stable COPD patients was spun down to collect the cells. To extract genomic DNA from Gram-positive bacteria more efficiently, QIAGEN's DNA extraction protocol was optimized as follows: Added Buffer ATL to the pellets and used bead tubes and tissue homogenizers to break cell walls; then added proteinase K and incubated; after adding Buffer AL and ethanol, pipetted the mixture into a DNeasy spin column then centrifuged; washed the column with Buffer AW1 and Buffer AW2, finally added 50 microL Buffer AE to elute DNA. After measuring the total DNA concentration, the bacterial 16S rDNA was amplified by PCR and amplicon libraries were created for further determination. RESULTS: The DNA content of BALF with optimized protocols was 467.5 (135.0-1697.5) ng, which was significantly higher than those extracted with phenol-chloroform 95.0 (0-612.5) ng. After optimizing, more 16S rDNA PCR production can be obtained for future analysis (P = 0.002). CONCLUSION: The optimized DNA extraction methods combining DNA isolation kits with bead-beating were more efficient in isolating tiny metagenomic DNA from BALF.

[The biological functions of lysine methyltransferase PR-SET7].

PR-SET7 (also named SET8 or KMT5a) is a sole lysine methyltransferase that catalyzes monomethylation of histone H4 lysine 20 (H4K20me1) in higher eukaryotes. The abundance of PR-SET7 is dynamically mediated by the distinct E3 ubiquitin ligases in different cell cycle phases. PR-SET7 is closely related to the regulation of cell proliferation, and the H4K20me1 catalyzed by PR-SET7 has been implicated in regulating the diverse biological processes, including DNA replication, chromosome condensation and the activation of DNA replication checkpoints. Loss of PR-SET7 results in mas-sive DNA damage, cell cycle arrest and induction of apoptosis. In addition, PR-SET7 involves in regulating the transcrip-tion of several genes, such as ERa, Wnt and p53. PR-SET7 is also essential for individual development and participates in the formation of genomic imprinting. Moreover, PR-SET7 has been reported to promote tumorigenesis and metastasis, sug-gesting that PR-SET7 may be a potential target for cancer treatment. In this review, we focus on analyzing the structure of PR-SET7 and factors influencing histone modification on regulation of PR-SET7, and discuss the mechanisms by which PR-SET7 modulates cell-cycle progression, gene transcription, individual development and tumorigenesis.

Zearalenone induces the senescence of cardiovascular cells in vitro and in vivo.

Zearalenone is a contaminant in food and feed products. It has been reported that zearalenone could lead to serious damage to health. So far, it is unclear whether zearalenone could lead to cardiovascular aging-related injury. For this, we assessed the effect of zearalenone on cardiovascular aging. Cardiomyocyte cell lines and primary coronary endothelial cells were used as two cell models in vitro experiments, and Western-blot, indirect immunofluorescence, and flow cytometry were performed to study the effect of zearalenone on cardiovascular aging. Experimental results indicated zearalenone treatment increased Sa-ß-gal positive cell ratio, and the expression of senescence markers (p16 and p21) was significantly upregulated. Additionally zearalenone upregulated the inflammation and oxidative stress in cardiovascular cells. Furthermore, the effect of zearalenone on cardiovascular aging was also evaluated in vivo, and the results indicated that zearalenone treatment also led to the aging of myocardial tissue. These findings suggest that zearalenone could lead to cardiovascular aging-related injury. Furthermore, we also preliminarily explored the potential effect of zeaxanthin (which is a powerful antioxidant) on zearalenone-caused aging-related damage in vitro cell model, and found that zeaxanthin could alleviate zearalenone-induced aging-related damage. Collectively, the most important finding of the current work is that zearalenone could lead to cardiovascular aging. Next in importance, we also found that zeaxanthin could partially alleviate zearalenone-induced cardiovascular aging in vitro, indicating that zeaxanthin can be used as a drug or functional food to treat cardiovascular damage caused by zearalenone.

IRX2 activated by jumonji domain-containing protein 2A is crucial for cardiac hypertrophy and dysfunction in response to the hypertrophic stimuli.

BACKGROUND: Iroquois homeobox 2 (IRX2) is a member of the Iroquois family whose upregulation has been potentially correlated to cardiac hypertrophy. This work studied the function of IRX2 and its related molecules in hypertrophic cardiomyopathy (HCM). METHODS: A GEO dataset GSE32453 was analyzed to identify aberrantly expressed genes in HCM. Altered expression of IRX2 was induced in mice by lentivirus injection, followed by angiotensin II (Ang II) treatment to induce HCM. The function of IRX2 knockdown in ventricular dysfunction, heart volume and pathological changes in mice, and in surface area, oxidative stress and apoptosis of isolated cardiomyocytes were examined. Binding relationship between jumonji domain-containing protein 2A (JMJD2A) and IRX2 was predicted by online tools and validated. The interaction between JMJD2A and IRX2 in HCM development was examined by joint interventions. RESULTS: IRX2 was highly expressed in heart tissues with HCM. IRX2 knockdown prevented mice from Ang II-induced ventricular dysfunction, cardiac hypertrophy, inflammation and fibrosis in mouse heart, and it decreased the levels of cardiac hypertrophy-related markers, oxidative stress response, and apoptosis of Ang II-treated cardiomyocytes. JMJD2A catalyzed demethylation of H3K9me3 near the IRX2 promoter to activate its transcription. JMJD2A knockdown similarly exerted protective functions against cardiac hypertrophy in vivo and in vitro, but the protection was blocked upon further IRX2 upregulation. IRX2 was found to increase the Wnt/ß-catenin signaling activation. CONCLUSION: This work reports that JMJD2A activates IRX2 transcription and the Wnt/ß-catenin signaling to induce cardiac hypertrophy and dysfunction in HCM.