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Queen bee acid (QBA), which is exclusively found in royal jelly, has anti-inflammatory, antihypercholesterolemic, and antiangiogenic effects. A recent study demonstrated that QBA enhances autophagic flux in the heart. Considering the significant role of autophagy in the development of myocardial ischemia/reperfusion (I/R) injury, we investigated the effect of pretreatment with QBA on myocardial damage. In an in vivo model, left coronary artery blockage for 30 min and reperfusion for 2 h were used to induce myocardial I/R. In an in vitro model, neonatal rat cardiomyocytes (NRCs) were exposed to 3 h of hypoxia and 3 h of reoxygenation (H/R). Our results showed that pretreatment with QBA increased the cell viability of cardiomyocytes exposed to H/R in a dose-dependent manner, and the best protective concentration of QBA was 100 µM. Next, we noted that QBA pretreatment (24h before H/R) enhanced autophagic flux and attenuated mitochondrial damage, cardiac oxidative stress and apoptosis in NRCs exposed to H/R injury, and these effects were weakened by cotreatment with the autophagy inhibitor bafilomycin A1 (Baf). In addition, similar results were observed when QBA (10 mg/kg) was injected intraperitoneally into I/R mice 30 min before ischemia. Compared to mice subjected to I/R alone, those treated with QBA had decreased myocardial infarct area and increased cardiac function, whereas, these effects were partly reversed by Baf. Notably, in NRCs exposed to H/R, tandem fluorescent mRFP-GFP-LC3 assays indicated increased autophagosome degradation due to the increase in autophagic flux upon QBA treatment, but coinjection of Baf blocked autophagic flux. In this investigation, no notable adverse effects of QBA were detected in either cellular or animal models. Our findings suggest that QBA pretreatment mitigates myocardial I/R injury by eliminating dysfunctional mitochondria and reducing reactive oxygen species via promoting autophagic flux.

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BACKGROUND AND PURPOSE: Doxorubicin is widely used in the treatment of malignant tumours, but doxorubicin-induced cardiotoxicity severely limits its clinical application. Spexin is a neuropeptide that acts as a novel biomarker in cardiovascular disease. However, the effects of spexin on doxorubicin-induced cardiotoxicity is unclear. EXPERIMENTAL APPROACH: We established a model of doxorubicin-induced cardiotoxicity both in vivo and in vitro. Levels of cardiac damage in mice was assessed through cardiac function assessment, determination of serum cardiac troponin T and CKMB levels and histological examination. CCK8 and PI staining were used to assess the doxorubicin-induced toxicity in cultures of cardiomyocytes in vitro. Ferroptosis was assessed using FerroOrange staining, determination of MDA and 4-HNE content and ferroptosis-associated proteins SLC7A11 and GPX4. Mitochondrial membrane potential and lipid peroxidation levels were measured using TMRE and C11-BODIPY 581/591 probes, respectively. Myocardial autophagy was assessed by expression of P62 and Beclin1. KEY RESULTS: Spexin treatment improved heart function of mice with doxorubicin-induced cardiotoxicity, and attenuated doxorubicin-induced cardiotoxicity by decreasing iron accumulation, abnormal lipid metabolism and inhibiting ferroptosis. Interestingly, doxorubicin caused excessive autophagy in cardiomyocyte in culture, which could be alleviated by treatment with spexin. Knockdown of Beclin 1 eliminated the protective effects of spexin in mice with DIC. CONCLUSION AND IMPLICATIONS: Spexin ameliorated doxorubicin-induced cardiotoxicity by inhibiting excessive autophagy-induced ferroptosis, suggesting that spexin could be a drug candidate against doxorubicin-induced cardiotoxicity. Beclin 1 might be critical in mediating the protective effect of spexin against doxorubicin-induced cardiotoxicity.

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INTRODUCTION: Ferroptosis, a newly identified type of programmed cell death type, has been proven to contribute to the progression of myocardial ischemia/reperfusion (I/R) injury. However, little is known about ferroptosis regulation in I/R injury. OBJECTIVES: We identified activating transcription factor 3 (ATF3) as a vital regulator of I/R induced ferroptosis and investigated the effects and potential mechanism of ATF3 in cardiac ferroptosis. METHODS: In this study, the dynamic RNA-sequencing (RNA-seq) analysis were performed on mouse hearts exposed to different I/R schedules to identify that ATF3 represents an important modulatory molecule in myocardial I/R injury. Then knockout, rescue and overexpression methods were used in mice and neonatal mouse cells (NMCs) to illustrate the effect of ATF3 on myocardial I/R injury. Loss/gain of function techniques were used both in vivo and in vitro to explore the effects of ATF3 on ferroptosis in I/R injury. Furthermore, chromatin immunoprecipitation sequence (ChIP-seq) analysis was performed in the AC16 human cardiomyocyte cell line to investigate potential genes regulated by ATF3. RESULTS: ATF3 expression reached highest level at early stage of reperfusion, knockout of ATF3 significantly aggravated I/R injury, which could be rescued by ATF3 re-expression. Knockout and the re-expression of ATF3 changed the transcription levels of multiple ferroptosis genes. In addition, results showed that overexpression of ATF3 inhibits cardiomyocyte ferroptosis triggered by erastin and RSL3. Lastly, ChIP-seq and dual luciferase activity analysis revealed ATF3 could bind to the transcription start site of Fanconi anaemia complementation group D2 (FANCD2) and increased the FANCD2 promoter activity. Furthermore, we first demonstrated that overexpression of FANCD2 exerts significant anti-ferroptosis and cardioprotective effect on AC16 cell H/R injury. CONCLUSION: ATF3 inhibits cardiomyocyte ferroptotic death in I/R injury, which might be related with regulating FANCD2. Our study provides new insight into the molecular target for the therapy of myocardial I/R injury.

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PRMT1, a major arginine methyltransferase, plays critical roles in transcription, DNA damage response, and cell proliferation. Although we have previously discovered the crucial roles of PRMT1 for oligodendrocyte lineage progression in the central nervous system of neural stem cell-specific PRMT1 conditional knockout (PRMT1-CKO) mice, the context of other glial cell states that may cause the hypomyelination phenotype in PRMT1-CKO mice has not been explored so far. Here, we performed RNA-seq of the neonatal cortices of PRMT1-CKO mice to reveal overall gene expression changes and show the up-regulation of inflammatory signaling which is generally mediated by astrocytes and microglia in advance of the myelination defects. In particular, qRT-PCR analyses revealed Interleukin-6 (Il-6), a major central nervous system cytokine, was dramatically increased in the PRMT1-CKO brains. The gene expression changes led to augmentation of glial fibrillary acidic protein and Vimentin protein levels in PRMT1-CKO mice, showing severe reactive astrogliosis after birth. We further show that IBA1-positive and CD68-positive activated microglia were increased in PRMT1-CKO mice, in spite of intact Prmt1 gene expression in purified microglia from the mutant mice. Our results indicate that PRMT1 loss in the neural stem cell lineage causes disruptive changes in all glial types perturbing postnatal brain development and myelination.

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Heart failure and chronic kidney disease are major causes of morbidity and mortality internationally. Although these dysfunctions are common and frequently coexist, the factors involved in their relationship in cardiorenal regulation are still largely unknown, mainly due to a lack of detailed molecular targets. Here, we found the increased plasma histamine in a preclinical mouse model of severe cardiac dysfunction, that had been cotreated with angiotensin II (Ang II), nephrectomy, and salt (ANS). The ANS mice exhibited impaired renal function accompanied with heart failure, and histamine depletion, by the genetic inactivation of histidine decarboxylase in mice, exacerbated the ANS-induced cardiac and renal abnormalities, including the reduction of left ventricular fractional shortening and renal glomerular and tubular injuries. Interestingly, while the pharmacological inhibition of the histamine receptor H3 facilitated heart failure and kidney injury in ANS mice, administration of the H3 agonist immethridine (Imm) was protective against cardiorenal damages. Transcriptome analysis of the kidney and biochemical examinations using blood samples illustrated that the increased inflammation in ANS mice was alleviated by Imm. Our results extend the pharmacological use of H3 agonists beyond the initial purposes of its drug development for neurogenerative diseases and have implications for therapeutic potential of H3 agonists that invoke the anti-inflammatory gene expression programming against cardiorenal damages.

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Protein arginine methyltransferase PRMT5 synthesizes the symmetric dimethylarginine in nuclear and cytoplasmic proteins such as histone H2A, H4 and several non-histone proteins that are required for a variety of biological processes. Currently, two splice variants (v1 and v2) of murine PRMT5 have been deposited in the NCBI sequence database, in which PRMT5-v1 and -v2 contain different 33 and 16 amino acids at the N-terminal sequences, respectively. Here we showed that murine PRMT5-v1 is stable, but PRMT5-v2 is constantly degraded through both the ubiquitin proteasome system (UPS) and the autophagic-lysosomal pathway (ALP) in an N-terminal sequence-dependent manner. Furthermore, inhibition of UPS and ALP elevated the stability of PRMT5-v2 that made it localized in the nucleus and the cytoplasm. In addition, PRMT5-v2 exhibited the enzyme activity to catalyze histone H2A and H4 methylation. Notably, we found that the heat shock protein (Hsp) 70 specially recognizes the N-terminal sequence of PRMT5-v2 and the carboxyl terminus of Hsp70-interacting protein (CHIP) is required for poly-ubiquitination and the degradation of PRMT5-v2. These results suggest that Hsp70/CHIP chaperone-mediated protein degradation system is crucial in the regulation of PRMT5-v2 turnover, which has the potential to balance the symmetrical arginine dimethylation in cells.

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NH3-SCR is an environmentally important reaction for the abatement of NO x from different resources. MnO2-based catalyst has attracted significant attention due to the excellent activity. In this paper, a series of MnWO x /TiO2-SiO2 catalysts were prepared by liquid-phase deposition method. The catalysts were characterized by N2 adsorption/desorption, XRD, TEM, XPS, FT-IR, H2-TPR, TG and water adsorption capacity. The existence of SiO2 improved the SO2 and H2O resistance of the MnWO x /TiO2-SiO2 catalyst without decreasing the NH3-SCR activity. Under the reaction conditions of 260°C and 60 000 ml gcata h-1 gas hourly space velocity (GHSV), the NO conversion was kept stable at about 95% for 140 min on stream. The excellent performance of MnWO x /TiO2-SiO2 catalyst is considered to be originated from the texture properties and active species dispersion improvement by SiO2 in the support and low-temperature preparation.

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Males and females share the same genetic code, but gene expression profile often displays differences between two sexes. Mouse embryonic fibroblasts (MEFs) have been used to experiment as a useful tool to test gene function. They have also been characterized by gender-based differences in expressed genes such as Y-linked Sry or X-linked Hprt. However, there is no report on sex differences in global gene expression. Here, using the next-generation RNA sequencing, we compared the comprehensive transcriptome of MEFs derived from two sexes. In comparison with the female group, the male group up-regulated 27 differentially expressed genes (DEGs), in which a male-specific histone demethylase KDM5D gene is included, and 7 DEGs were down-regulated. Based on the results by searching the ENCODE analysis, it was shown that the expression of 15 genes identified is potentially regulated by the methylation of H3K4me1 or H3K4me3. Interestingly, we demonstrated that both of H3K4 methylation are induced by knocking down KDM5D, which causes changes in patterns of eight DEGs found in male MEFs. Collectively, these data not only suggest an importance of KDM5D-mediated demethylation of H3K4 involved in the sexually dimorphic gene expression in male MEFs, but also may provide information regarding sex-dependent changes in gene expression when MEFs are used for experiments.

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Protein arginine methyltransferase 1 (PRMT1) catalyzes the asymmetric dimethylation of arginine residues in proteins and methylation of various RNA-binding proteins and is associated with alternative splicing in vitro. Although PRMT1 has essential in vivo roles in embryonic development, CNS development, and skeletal muscle regeneration, the functional importance of PRMT1 in the heart remains to be elucidated. Here, we report that juvenile cardiomyocyte-specific PRMT1-deficient mice develop severe dilated cardiomyopathy and exhibit aberrant cardiac alternative splicing. Furthermore, we identified previously undefined cardiac alternative splicing isoforms of four genes (Asb2, Fbxo40, Nrap, and Eif4a2) in PRMT1-cKO mice and revealed that eIF4A2 protein isoforms translated from alternatively spliced mRNA were differentially ubiquitinated and degraded by the ubiquitin-proteasome system. These findings highlight the essential roles of PRMT1 in cardiac homeostasis and alternative splicing regulation.

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Ice repellent coatings have been studied and keenly sought after for many years, where any advances in the durability of such coatings will result in huge energy savings across many fields. Progress in creating anti-ice and anti-frost surfaces has been particularly rapid since the discovery and development of slippery, liquid infused porous surfaces (SLIPS). Here we use SLIPS-coated differential scanning calorimeter (DSC) pans to investigate the effects of the surface modification on the nucleation of supercooled water. This investigation is inherently different from previous studies which looked at the adhesion of ice to SLIPS surfaces, or the formation of ice under high humidity conditions. Given the stochastic nature of nucleation of ice from supercooled water, multiple runs on the same sample are needed to determine if a given surface coating has a real and statistically significant effect on the nucleation temperature. We have cycled supercooling to freezing and then thawing of deionized water in hydrophilic (untreated aluminum), hydrophobic, superhydrophobic, and SLIPS-treated DSC pans multiple times to determine the effects of surface treatment on the nucleation and subsequent growth of ice. We find that SLIPS coatings lower the nucleation temperature of supercooled water in contact with statistical significance and show no deterioration or change in the coating performance even after 150 freeze-thaw cycles.

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