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Objective: Urocortin possesses cardioprotective properties against the damaging effects of ischemia/reperfusion injury. Our previous study demonstrated that urocortin can induce both endothelium-dependent and -independent coronary relaxation. However, the mechanisms thereby urocortin triggers endothelium-independent relaxation have not been investigated. The present study aimed to examine the role of cyclic AMP and Ca2+-activated K+ channels in the relaxant response to urocortin in the isolated endothelium-denuded rat left anterior descending coronary arteries. Methods: Changes in vessel tension were measured by using a force transducer built in a Multi Myograph System. Results: In 9,11-dideoxy-11α,9α-epoxy-methanoprostaglandin F2α (U46619)-contracted rings, urocortin-induced relaxation (pD2: 8.40±0.04) was significantly reduced by cyclic AMP-dependent protein kinase (PKA) inhibitors, Rp-cAMPS triethylamine (Rp-cAMPS) and KT 5720. Treatment with the large-conductance Ca2+-activated K+ channel blockers, iberiotoxin or tetraethylammonium ions (TEA+) attenuated urocortin-induced relaxation; this effect was abolished in the presence of 200 nmol/l KT 5720. In contrast, apamin (small-conductance Ca2+-activated K+ channel blocker), glibenclamide (ATP-sensitive K+ channel blocker), or BaCl2 (inwardly rectifier K+ channel blocker) had no effect. Urocortin-induced relaxation was reduced in rings contracted with increasing concentrations of extracellular K+ (35 and 50 mmol/l). Treatment with TEA+ or Rp-cAMPS inhibited the relaxant effect of urocortin in 35 mmol/l K+-contracted rings. Combined treatment with TEA+ and Rp-cAMPS had no additional effect. Similarly, forskolin produced significantly less relaxant response in 50 mmol/l K+-contracted than U46619-contracted rings. Forskolin-induced relaxation was attenuated by pretreatment with 3 mmol/l TEA+. Conclusion: Urocortin relaxed the rat coronary artery in substantial part via activation of the vascular Ca2+-activated K+ channels and this effect appears to be primarily mediated through PKA-dependent intracellular mechanisms. [Copyright &y& Elsevier]

Objectives: Estrogen exerts cardiac protection via multiple cellular mechanisms. Estrogen modifies vasodilatation induced by certain relaxants such as β-adrenoceptor agonists. However, little is known whether low concentrations of β-adrenoceptor agonists would reciprocally influence the acute relaxant response to estrogen. The present study was designed to investigate the synergistic interaction between isoproterenol and 17β-estradiol, and the role of endothelium and cyclic AMP-dependent pathway in this interaction. Methods: Changes in vessel tone of the isolated rat mesenteric artery rings were measured using a force–displacement Grass transducer. Results: In 9,11-dideoxy-11α, 9α-epoxy-methanoprostaglandin F2α-preconstricted endothelium-intact rings, 17β-estradiol induced relaxations with pD2 of 5.06±0.06. Pretreatment of endothelium-intact rings with isoproterenol (1–3×10−9 M, 1 h incubation time) significantly enhanced 17β-estradiol-induced relaxation. This effect was inhibited by Rp-cGMPS triethylamine (3×10−6 M), and abolished in the presence of 3×10−5 M NG-nitro-l-arginine methyl ester or in endothelium-denuded rings. The effect of isoproterenol was antagonized by propranolol (3×10−6 M), ICI 118,551 (3×10−6 M), but not by atenolol (10−5 M). Rp-cAMPS triethylamine (3×10−6 M) abolished the effect of isoproterenol. Besides, exposure to 3×10−9 M forskolin for 1 h also potentiated the relaxant response to 17β-estradiol. Conclusion: In endothelium-intact rat mesenteric arteries pretreatment with low concentrations of isoproterenol enhanced the acute relaxant response to 17β-estradiol. This enhancement was dependent on the presence of endothelium and abolished by l-NAME via a β2-adrenoceptor-mediated cyclic AMP-dependent mechanism. [Copyright &y& Elsevier]

Currently, there is no effective molecular-based therapy for triple-negative breast cancer (TNBC). Canonical transient receptor potential isoform 3 (TRPC3) was previously shown to be upregulated in breast cancer biopsy tissues when compared to normal breast tissues. However, the biological role of TRPC3 in breast cancer still remains to be elucidated. In this study, subcellular fractionation followed by Western blot and immunocytochemistry showed that TRPC3 was over-expressed on the plasma membrane of TNBC line MDA-MB-231 when compared to an estrogen receptor-positive cell line MCF-7. TRPC3 blocker Pyr3 and dominant negative of TRPC3 attenuated proliferation, induced apoptosis and sensitized cell death to chemotherapeutic agents in MDA-MB-231 as measured by proliferation assays. Interestingly, Ras GTPase-activating protein 4 (RASA4), a Ca2+-promoted Ras-MAPK pathway suppressor, was found to be located on the plasma membrane of MDA-MB-231. Blocking TRPC3 decreased the amount of RASA4 located on the plasma membrane, with concomitant activation of MAPK pathways. Our results suggest that, in TNBC MDA-MB-231 cells, Ca2+ influx through TRPC3 channel sustains the presence of RASA4 on the plasma membrane where it inhibits the Ras-MAPK pathway, leading to proliferation and apoptosis resistance. Our study reveals the novel TRPC3-RASA4-MAPK signaling cascade in TNBC cells and suggests that TRPC3 may be exploited as a potential therapeutic target for TNBC. [ABSTRACT FROM AUTHOR]

Although benzothiazole and its derivatives (BTHs) are considered emerging contaminants in diverse environments and organisms, little information is available about their contamination profiles and health impact in ambient particles. In this study, an optimized method of ultrasound-assisted extraction coupled with the selected reaction monitoring (SRM) mode of GC-EI-MS/MS was applied to characterize and analyze PM 2.5 -bound BTHs from three cities of China (Guangzhou, Shanghai, and Taiyuan) during the winter of 2018. The total BTH concentration (ΣBTHs) in PM 2.5 samples from the three cities decreased in the order of Guangzhou > Shanghai > Taiyuan, independently of the PM 2.5 concentration. Despite the large variation in concentration of ΣBTHs in PM 2.5 , 2-hydroxybenzothiazole (OTH) was always the predominant compound among the PM 2.5 -bound BTHs and accounted for 50–80% of total BTHs in the three regions. Results from human exposure assessment and toxicity screening indicated that the outdoor exposure risk of PM 2.5 -bound BTHs in toddlers was much higher than in adults, especially for OTH. The developmental and reproduction toxicity of OTH was further explored in vivo and in vitro. Exposure of mouse embryonic stem cells (mESCs) to OTH for 48 h significantly increased the intracellular reactive oxygen species (ROS) and induced DNA damage and apoptosis via the functionally activating p53 expression. In addition, the growth and development of zebrafish embryos were found to be severely affected after OTH treatment. An overall metabolomics study was conducted on the exposed zebrafish larvae. The results indicated that exposure to OTH inhibited the phenylalanine hydroxylation reaction, which further increased the accumulation of toxic phenylpyruvate and acetylphenylalanine in zebrafish. These findings provide important insights into the contamination profiles of PM 2.5 -bound BTHs and emphasize the health risk of OTH. Unlabelled Image • BTHs were detected in 26 outdoor PM 2.5 samples from Guangzhou and Taiyuan, China. • OTH was the predominant compound among the PM 2.5 -bound BTHs in the three regions. • OTH and the outdoor exposure risk of toddlers were much higher than that of adults. • OTH has potential developmental and reproduction toxicity. [ABSTRACT FROM AUTHOR]

Canonical transient receptor potential isoform 3 (TRPC3), a calcium-permeable non-selective cation channel, has been reported to be upregulated in breast cancers and a modulator of cell migration. Calcium-sensitive transcription factor NFATc1, which is important for cell migration, was shown to be frequently activated in triple negative breast cancer (TNBC) biopsy tissues. However, whether TRPC3-mediated calcium influx would activate NFATc1 and affect the migration of TNBC cells, and, if yes, the underlying mechanisms involved, remain to be investigated. By immunostaining followed by confocal microscopy, TNBC lines MDA-MB-231 and BT-549 were both found to express TRPC3 on their plasma membrane while ER + line MCF-7 and HER2 + line SK-BR3 do not. Blockade of TRPC3 by pharmacological inhibitor Pyr3 or stable knockdown of TRPC3 by lentiviral vector both inhibited cell migration as measured by wound healing assay. Importantly, blocking TRPC3 by Pyr3 or knockdown of TRPC3 both caused the translocation of NFATc1 from the nucleus to the cytosol as revealed by confocal microscopy. Interestingly, NFATc1 was found to bind to the promoter of glypican 6 (GPC6) as determined by chromatin immunoprecipitation assay. Consistently, knockdown of TRPC3 decreased the expression of GPC6 as revealed by western blotting. Moreover, long-term knockdown of GPC6 by lentiviral vector also consistently decreased the migration of TNBC cells. Intriguingly, GPC6 proteins physically interact with vinculin in MDA-MB-231 as determined by co-immunoprecipitation. Blockade of TRPC3, knockdown of TRPC3 or knockdown of GPC6 all induced larger, stabilized actin-bound peripheral focal adhesion (FA) formations in TNBC cells as determined by co-staining of actin and vinculin followed by confocal microscopy. These large, stabilized actin-bound peripheral FAs indicated a defective FA turnover, and were reported to be responsible for impairing directed cell migration. Our results suggest that, in TNBC cells, calcium influx through TRPC3 channel positively regulates NFATc1 nuclear translocation and GPC6 expression, which maintains the dynamics of FA turnover and optimal cell migration. Our study reveals a novel TRPC3-NFATc1-GPC6-vinculin signaling cascade in maintaining the migration of TNBC cells., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The COVID-19 pandemic has raised awareness about various environmental issues, including PM 2.5 pollution. Here, PM 2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM 2.5 in Guangzhou, with an emphasis on heavy pollution. The lockdown led to large reductions in industrial and traffic emissions, which significantly reduced PM 2.5 concentrations in Guangzhou. Interestingly, the trend of PM 2.5 concentrations was not consistent with traffic and industrial emissions, as minimum concentrations were observed in the fourth period (3/01-3/31, 22.45 μg/m 3 ) of the lockdown. However, the concentrations of other gaseous pollutants, e.g., SO 2 , NO 2 and CO, were correlated with industrial and traffic emissions, and the lowest values were noticed in the second period (1/24-2/03) of the lockdown. Meteorological correlation analysis revealed that the decreased PM 2.5 concentrations during COVID-19 can be mainly attributed to decreased industrial and traffic emissions rather than meteorological conditions. When meteorological factors were included in the PM 2.5 composition and backward trajectory analyses, we found that long-distance transportation and secondary pollution offset the reduction of primary emissions in the second and third stages of the pandemic. Notably, industrial PM 2.5 emissions from western, southern and southeastern Guangzhou play an important role in the formation of heavy pollution events. Our results not only verify the importance of controlling traffic and industrial emissions, but also provide targets for further improvements in PM 2.5 pollution., (Copyright © 2021. Published by Elsevier B.V.)

The tumor suppressor p16 protein is an endogenous CDK4/6 inhibitor. Inactivation of its encoding gene is found in nearly half of human cancers. Restoration of p16 function via adenovirus-based gene delivery has been shown to be effective in suppressing aberrant cell growth in many types of cancer, however, the potential risk of insertional mutagenesis in genomic DNA remains a major concern. Thus, there has been great interest in developing efficient strategies to directly deliver proteins into cells as an alternative that can avoid such safety concerns while achieving a comparable therapeutic effect. Nevertheless, intracellular delivery of protein therapeutics remains a challenge. Our group has recently developed a protein delivery platform based on an engineered Pos3Aa protein that forms sub-micrometer-sized crystals in Bacillus thuringiensis cells. In this report, we describe the further development of this platform (Pos3AaTM) via rationally designed site-directed mutagenesis, and its resultant potency for the delivery of cargo proteins into cells. Pos3AaTM-based fusion protein crystals are shown to exhibit improved release of their cargo proteins as demonstrated using a model mCherry protein. Importantly, this Pos3AaTM platform is able to mediate the efficient intracellular delivery of p16 protein with significant endosomal escape, resulting in p16-mediated inhibition of CDK4/6 kinase activity and Rb phosphorylation, and as a consequence, significant cell cycle arrest and cell growth inhibition. These results validate the ability of these improved Pos3AaTM crystals to mediate enhanced cytosolic protein delivery and highlight the potential of using protein therapeutics as selective CDK4/6 inhibitors for cancer therapy. STATEMENT OF SIGNIFICANCE: Cytosolic delivery of bioactive therapeutic proteins capable of eliciting therapeutic benefit remains a significant challenge. We have previously developed a protein delivery platform based on engineered Pos3Aa protein crystals with excellent cell-permeability and endosomal escape properties. In this report, we describe the rational design of an improved Pos3Aa triple mutant (Pos3AaTM) with enhanced cargo release. We demonstrate that Pos3AaTM-mCherry-p16 fusion crystals can efficiently deliver p16 protein, a CDK4/6 inhibitor frequently inactivated in human cancers, into p16-deficient UM-SCC-22A cells, where it promotes significant G1 cell cycle arrest and cell growth inhibition. These results highlight the ability of the Pos3AaTM platform to promote potent cytosolic delivery of protein therapeutics, and the efficacy of p16 protein delivery as an effective strategy for treating cancer., Competing Interests: Declaration of Competing Interest A PCT application (PCT/CN2020/084939) related to this work has been filed with M.K.C., M.M.L. and Z.F. as inventors., (Copyright © 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Calcium controls the excitation-contraction coupling in cardiomyocytes. Embryonic stem cell-derived cardiomyocytes (ESC-CMs) are an important cardiomyocyte source for regenerative medicine and drug screening. Transient receptor potential vanilloid 1 (TRPV1) channels are nonselective cation channels that permeate sodium and calcium. This study aimed to investigate whether TRPV1 channels regulate the electrophysiological characteristics of ESC-CMs. If yes, what is the mechanism behind? By immunostaining and subcellular fractionation, followed by western blotting, TRPV1 was found to locate intracellularly. The staining pattern of TRPV1 was found to largely overlap with that of the sarco/endoplasmic reticulum Ca 2+ -ATPase, the sarcoplasmic reticulum (SR) marker. By electrophysiology and calcium imaging, pharmacological blocker of TRPV1 and the molecular tool TRPV1β (which could functionally knockdown TRPV1) were found to decrease the rate and diastolic depolarization slope of spontaneous action potentials, and the amplitude and frequency of global calcium transients. By calcium imaging, in the absence of external calcium, TRPV1-specific opener increased intracellular calcium; this increase was abolished by preincubation with caffeine, which could deplete SR calcium store. The results suggest that TRPV1 controls calcium release from the SR. By electrophysiology, TRPV1 blockade and functional knockdown of TRPV1 decreased the Na + /Ca2 + exchanger (NCX) currents from both the forward and reverse modes, suggesting that sodium and calcium through TRPV1 stimulate the NCX activity. Our novel findings suggest that TRPV1 activity is important for regulating the spontaneous activity of ESC-CMs and reveal a novel interplay between TRPV1 and NCX in regulating the physiological functions of ESC-CMs., (© 2021 Wiley Periodicals LLC.)

Background: Biological pacemakers consisting of pluripotent stem cell-derived cardiomyocytes are potentially useful for treating bradycardia. However, tachyarrhythmia caused by derived cardiomyocytes themselves is one of main barriers hampering their clinical translation. An in-depth understanding of the mechanisms underlying the spontaneous action potential (a.k.a. automaticity) might provide potential approaches to solve this problem. The aim of this project is to study the role of canonical transient receptor potential isoform 7 (TRPC7) channels in regulating the automaticity of embryonic stem cell-derived cardiomyocytes (ESC-CMs)., Methods and Results: By Western blotting, the expression of TRPC7 was found to be increased during the differentiation of mouse ESC-CMs (mESC-CMs). Adenovirus-mediated TRPC7 knockdown decreased while overexpression increased the frequency of Ca 2+ transients (CaTs), local Ca 2+ releases (LCRs), and action potentials (APs) as detected by confocal microscopy and whole-cell patch-clamping. TRPC7 was found to be positively associated with the activity of ryanodine receptor 2 (RyR2), sarco/endoplasmic reticulum Ca 2+ -ATPase (SERCA), and sodium-calcium exchanger (NCX) but not hyperpolarization-activated, cyclic nucleotide-gated channel (HCN), and inositol trisphosphate receptor (IP3R). Knockdown or overexpression of TRPC7 did not alter the expression of HCN4, Cav1.3, Cav3.1, Cav3.2, IP3R1, RyR2, and SERCA but positively regulated the phosphorylation of RyR2 at S2814 and phospholamban (PLN) at T17. Moreover, the positive regulation of APs by TRPC7 was Ca 2+ -dependent, as overexpression of N-terminus of TRPC7 (dominant negative of TRPC7) which diminished the Ca 2+ permeability of TRPC7 decreased the AP frequency., Conclusions: TRPC7 regulates the automaticity of mESC-CMs through two mechanisms. On the one hand, TRPC7 positively regulates the intracellular Ca 2+ clock through the regulation of activities of both RyR2 and SERCA; on the other hand, TRPC7 also positively regulates the membrane clock via its influence on NCX activity. Altogether, our study reveals that TRPC7 is a potential drug target to manipulate the action potential firing rate of pluripotent stem cell-derived cardiomyocyte-based biological pacemakers to prevent tachyarrhythmia, a condition that might be encountered after transplantation.

Numerous experimental and epidemiological studies have demonstrated that exposure to PM 2.5 may result in pathogenesis of several major cardiovascular diseases (CVDs), which can be attributed to the combined adverse effects induced by the complicated components of PM 2.5 . Organic materials, which are major components of PM 2.5 , contain thousands of chemicals, and most of them are environmental hazards. However, the contamination profile and contribution to overall toxicity of PM 2.5 -bound organic components (OCs) have not been thoroughly evaluated yet. Herein, we aim to provide an overview of the literature on PM 2.5 -bound hydrophobic OCs, with an emphasis on the chemical identity and reported impairments on the cardiovascular system, including the potential exposure routes and mechanisms. We first provide an update on the worldwide mass concentration and composition data of PM 2.5 , and then, review the contamination profile of PM 2.5 -bound hydrophobic OCs, including constitution, concentration, distribution, formation, source, and identification. In particular, the link between exposure to PM 2.5 -bound hydrophobic OCs and CVDs and its possible underlying mechanisms are discussed to evaluate the possible risks of PM 2.5 -bound hydrophobic OCs on the cardiovascular system and to provide suggestions for future studies., Competing Interests: Declaration of competing interest The authors declare no conflict of interest with the study or preparation of the manuscript., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Although the bioaccumulation of organophosphate flame retardants (OPFRs) in aquatic organisms has been investigated, little information is available about their bioaccumulation in mammals following chronic inhalation exposure. To address this knowledge gap, C57BL/6 mice were exposed to 7 PM 2.5 -associated OPFRs via the trachea to study their bioaccumulation, tissue distribution, and urinary metabolites. Low (corresponding to the real PM 2.5 concentrations occurring during winter in Guangzhou), medium, and high dosages were examined. After 72 days' exposure, ∑OPFR concentrations in tissues from mice in the medium dosage group decreased in the order of intestine > heart > stomach > testis > kidney > spleen > brain > liver > lung > muscle. Of the OPFRs detected in all three exposure groups, chlorinated alkyl OPFRs were most heavily accumulated in mice. We found a significant positive correlation between the bioaccumulation ratio and octanol-air partition coefficient ( K OA ) in mice tissues for low log  K OW OPFR congeners (log  K OW ≤ 4, p < 0.05). Three urinary metabolites (di- p -cresyl phosphate: DCrP, diphenyl phosphate: DPhP, dibutyl phosphate: DnBP) were detected from the high dosage group. These results provide important insights into the bioaccumulation potential of OPFRs in mammals and emphasize the health risk of chlorinated alkyl OPFRs.

It has long been a puzzle in cancer treatment that despite the initial appearance of apoptosis, the process could be reversed in some cancer cells and often results in more aggressive tumors and metastasis. The mechanism for this recurrence is yet unknown. Here we report that human mammary carcinoma cells induced to undergo apoptosis could recover with increased tumorigenicity in vitro and in vivo, and induced lymph node metastasis. Specifically, the reversed cells underwent epithelial-to-mesenchymal transitions in the primary tumors in situ, and mesenchymal-to-epithelial transitions in the metastatic cells. Flow cytometry confirmed an elevated percentage of cells carrying cancer stem cells (CSCs) markers (CD44 + /CD24 - ) in the reversed breast cancer cell population, with hypomethylated CD44 promoters and hypermethylated CD24 promoters. More importantly, CSCs were generated anew from non-stem cancer cells after apoptosis reversal possibly through epigenetic modifications. The results from this study can open doors to discovering more effective cancer treatments by suppressing apoptosis reversal., (Copyright © 2018. Published by Elsevier Inc.)

Polycystic ovary syndrome (PCOS) is a common endocrine abnormality in women characterized by a menstrual disturbance with chronic anovulation and hyperandrogenism, polycystic ovaries, and insulin resistance. MicroRNAs (miRNAs) are important fine-tune regulators involved in various physiological and pathological processes, but their actions are not fully understood. In this study, we observed the increased expression of miR-27a-3p in the ovaries of mice with PCOS and explored its functions in primary mouse granulosa cells (mGCs) and the mouse granulosa-like tumor cell line, KK-1, using several approaches. QPCR results showed that miR-27a-3p expression was significantly higher in mGCs at the preantral follicle (PrF) stage. Using flow cytometry and hormone analysis, we found that overexpression of miR-27a-3p promoted apoptosis and inhibited estradiol (E 2 ) production in KK-1 cells. Moreover using a luciferase assay and Western blotting analysis, we verified that the gene of cyclic AMP response element (CRE)-binding protein 1 (Creb1) was a potential target of miR-27a-3p, which in effect hindered the expression of its downstream factor cytochrome P450 family 19 subfamily A polypeptide 1 (Cyp19a1). With the decrease of aromatase activity, testosterone (T) is reduced to dihydrotestosterone (DHT) and this exerts its effect of upregulation of the miR-27a-3p expression. The imbalance of androgen and E 2 levels affected by miR-27a-3p and its function of promoting GC apoptosis could be involved in the pathophysiology of PCOS. Our results indicate that miR-27a-3p in PCOS GCs may play an important role in ovarian follicular development and provide new insights into GC dysfunction in PCOS., (Copyright © 2017. Published by Elsevier Urban & Partner Sp. z o.o.)

Histone deacetylase (HDAC) inhibitors modulate acetylation/deacetylation of histone and nonhistone proteins. They have been widely used for cancer treatment. However, there have been only a few studies investigating the effect of HDAC inhibitors on vascular tone regulation, most of which employed chronic treatment with HDAC inhibitors. In the present study, we found that two hydroxamate-based pan-HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA), could partially but acutely relax high extracellular K + -contracted mouse aortas. SAHA and TSA also attenuated the high extracellular K + -induced cytosolic Ca 2+ rise and inhibited L-type Ca 2+ channel current in whole-cell patch-clamp. These data demonstrate that SAHA could inhibit L-type Ca 2+ channels to cause vascular relaxation. In addition, SAHA and TSA dose dependently relaxed the arteries precontracted with phenylephrine. The relaxant effect of SAHA and TSA was greater in phenylephrine-precontracted arteries than in high K + -contracted arteries. Although part of the relaxant effect of SAHA and TSA on phenylephrine-precontracted arteries was related to L-type Ca 2+ channels, both agents could also induce relaxation via a mechanism independent of L-type Ca 2+ channels. Taken together, HDAC inhibitors SAHA and TSA can acutely relax blood vessels via their inhibitory action on L-type Ca 2+ channels and via another L-type Ca 2+ channel-independent mechanism., (Copyright © 2017 by The Author(s).)

We have previously demonstrated that activation of prostacyclin (IP) receptors in human erythroleukemia (HEL) cells phosphorylates the signal transducer and activator of transcription 3 (STAT3) via Gα(s) and Gα(16) hybrid signalling. This current study was designed to determine if functional responses to cicaprost in HEL cells were dependent on STAT3 phosphorylation. Cicaprost significantly enhanced the rapid change in HEL cell morphology induced by phorbol-12-myristate-13-acetate (PMA), and this effect was inhibited by the IP receptor antagonist RO1138452 and a STAT3 inhibitory peptide. Other indicators of PMA-induced HEL cell differentiation, such as increased expression of CD41/CD61 and an increase in cell complexity/granularity, were inhibited by cicaprost in an IP receptor-dependent and STAT3-dependent manner. Although thrombopoietic cytokines promote megakaryocytic differentiation and platelet production via activation of STAT3, the predominant STAT3-dependent effects of cicaprost in HEL cells were inhibitory towards the process of PMA-induced megakaryocytopoeisis., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Pharmacological stimulation of fetal hemoglobin (HbF) expression may be a promising approach for the treatment of beta-thalassemia. In this study, the effects of Fructus trichosanthis (FT) were investigated in human erythroleukemic K562 cells for their gamma-globin mRNA and HbF-induction activities. The role of signaling pathways, including extracellular regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), was also investigated. It was found that the ethanol extract of FT significantly increased gamma-globin mRNA and HbF levels, determined by real-time reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay, respectively, in dose- and time-dependent manner. Total Hb (THb) levels were also elevated in the concentrations without cytotoxicity (<80 μg mL(-1)). Pre-treatment with p38 MAPK inhibitor SB203580 blocked the stimulatory effects of FT extract in total and HbF induction. In contrast, no change in HbF was observed when treated with ERK inhibitor PD98059. Furthermore, FT ethanol extract activated p38 MAPK and inhibited ERK signaling pathways in K562 cells, as revealed in western blotting analysis. In addition, SB203580 significantly abolished p38 MAPK activation when the cells were treated with FT. In summary, the ethanol extract of FT was found to be a potent inducer of HbF synthesis in K562 cells. The present data delineated the role of ERK and p38 MAPK signaling as molecular targets for pharmacologic stimulation of HbF production upon FT treatment.

The dried roots of Scutellaria baicalensis (S. baicalensis) Georgi (common name: Huangqin in China) have been widely employed for many centuries in traditional Chinese herbal medicine as popular antibacterial and antiviral agents. They are effective against staphylococci, cholera, dysentery, pneumococci and influenza virus. Baicalein, one of the major flavonoids contained in the dried roots, possesses a multitude of pharmacological activities. The glycoside of baicalein, baicalin is a potent anti-inflammatory and anti-tumor agent. This review describes the biological properties of baicalein (Table 1), which are associated with the prevention and treatment of cardiovascular diseases. Baicalein is a potent free radical scavenger and xanthine oxidase inhibitor, thus improving endothelial function and conferring cardiovascular protective actions against oxidative stress-induced cell injury. Baicalein lowers blood pressure in renin-dependent hypertension and the in vivo hypotensive effect may be partly attributed to its inhibition of lipoxygenase, resulting in reduced biosynthesis and release of arachidonic acid-derived vasoconstrictor products. On the other hand, baicalein enhances vasoconstricting sensitivity to receptor-dependent agonists such as noradrenaline, phenylephrine, serotonin, U46619 and vasopressin in isolated rat arteries. The in vitro effect is likely caused by inhibition of an endothelial nitric oxide-dependent mechanism. The anti-thrombotic, anti-proliferative and anti-mitogenic effects of the roots of S. baicalensis and baicalein are also reported. Baicalein inhibits thrombin-induced production of plasminogen activator inhibitor-1, and interleukin-1beta- and tumor necrosis factor-alpha-induced adhesion molecule expression in cultured human umbilical vein endothelial cells. The pharmacological findings have highlighted the therapeutic potentials of using plant-derived baicalein and its analogs for the treatment of arteriosclerosis and hypertension.

Urocortin and other hypothalamus corticotropin-releasing factor (CRF) polypeptides play biologically diverse roles in the stress, cardiovascular and inflammatory responses by acting on central and peripheral CRF receptors. Urocortin shows a significantly high sequence homology to CRF, and the concurrent expression of type-2 CRF (CRF2) receptors with urocortin in the heart suggests that urocortin may play a physiological role in the cardiac function. Urocortin is thought to be the endogenous agonist producing the cardiovascular actions previously attributed to CRF. This review highlights the current novel findings on the molecular and cellular mechanisms by which urocortin may exert its cardiovascular protective action.

Objectives: Estrogen exerts cardiac protection via multiple cellular mechanisms. Estrogen modifies vasodilatation induced by certain relaxants such as beta-adrenoceptor agonists. However, little is known whether low concentrations of beta-adrenoceptor agonists would reciprocally influence the acute relaxant response to estrogen. The present study was designed to investigate the synergistic interaction between isoproterenol and 17 beta-estradiol, and the role of endothelium and cyclic AMP-dependent pathway in this interaction., Methods: Changes in vessel tone of the isolated rat mesenteric artery rings were measured using a force-displacement Grass transducer., Results: In 9,11-dideoxy-11 alpha, 9 alpha-epoxy-methanoprostaglandin F(2 alpha)-preconstricted endothelium-intact rings, 17 beta-estradiol induced relaxations with pD(2) of 5.06 +/- 0.06. Pretreatment of endothelium-intact rings with isoproterenol (1-3 x 10(-9) M, 1 h incubation time) significantly enhanced 17 beta-estradiol-induced relaxation. This effect was inhibited by Rp-cGMPS triethylamine (3 x 10(-6) M), and abolished in the presence of 3 x 10(-5) M N(G)-nitro-L-arginine methyl ester or in endothelium-denuded rings. The effect of isoproterenol was antagonized by propranolol (3 x 10(-6) M), ICI 118,551 (3 x 10(-6) M), but not by atenolol (10(-5) M). Rp-cAMPS triethylamine (3 x 10(-6) M) abolished the effect of isoproterenol. Besides, exposure to 3 x 10(-9) M forskolin for 1 h also potentiated the relaxant response to 17 beta-estradiol., Conclusion: In endothelium-intact rat mesenteric arteries pretreatment with low concentrations of isoproterenol enhanced the acute relaxant response to 17 beta-estradiol. This enhancement was dependent on the presence of endothelium and abolished by L-NAME via a beta(2)-adrenoceptor-mediated cyclic AMP-dependent mechanism.