Effect of Ghrelin Intervention on the Ras/ERK Pathway in the Regulation of Heart Failure by PTEN.

OBJECTIVE: To study the possible mechanism of ghrelin in heart failure and how it works. METHOD: In vitro results demonstrated that ghrelin alleviates cardiac function and reduces myocardial fibrosis in rats with heart failure. Moreover, ghrelin intervention increased PTEN expression level and reduced ERK, c-jun, and c-Fos expression level; in vivo experiments demonstrated that ghrelin intervention reduces mast memory expression and increases cardiomyocyte surface area, PTEN expression level, ERK, c-jun, c-Fos expression level, and cell surface area, while ERK blockade suppresses mast gene expression and reduces cell surface area. RESULTS: In vitro experimental results prove that we have successfully constructed a rat model related to heart failure, and ghrelin can alleviate the heart function of heart failure rats and reduce myocardial fibrosis. In addition, ghrelin is closely related to the decrease of the expression levels of ERK, c-jun, and c-Fos, but it can also increase the expression of PTEN in the rat model; in vivo experiments proved that we successfully constructed an in vitro cardiac hypertrophy model, and the intervention of ghrelin would reduce the expression of hypertrophic memory and increase the surface area of cardiomyocytes, increase the expression level of PTEN, and reduce the expression levels of ERK, c-jun, and c-Fos, while the blockade of PTEN will increase the expression of hypertrophy genes and increase the cell surface area, while the blockade of ERK will increase the expression of hypertrophic genes, which in turn will make the cell surface area reducing. CONCLUSION: Ghrelin inhibits the phosphorylation and nuclear entry of ERK by activating PTEN, thereby controlling the transcription of hypertrophic genes, improving myocardial hypertrophy, and enhancing cardiac function.

Network pharmacology and experimental investigation of Rhizoma polygonati extract targeted kinase with herbzyme activity for potent drug delivery.

Rhizoma polygonati (Huangjing, RP) has been used for a long history with many chemical components in inducing anti-cancer, anti-aging, anti-diabetes, anti-fatigue, and more prevention of diseases or acts as nutrition sources in food. Here we investigated RP extract combination with kinase inhibitors in anti-cell growth and blockade in pathways targeting kinases. Experimental investigation and network pharmacology analysis were applied to test the potent kinase-mediated signaling. Herbzyme activity was determined by substrate with optical density measurement. Extract of processed RP inhibits cell growth in a much greater manner than alone when applied in combination with inhibitors of mTOR or EGFR. Moreover, processing methods of RP from Mount Tai (RP-Mount Tai) play essential roles in herbzyme activity of phosphatase suggesting the interface is also essential, in addition to the chemical component. The network pharmacology analysis showed the chemical component and target networks involving AKT and mTOR, which is consistent with experimental validation. Finally, EGFR inhibitor could be associated with nano-extract of RP-Mount Tai but not significantly affects the phosphatase herbzyme activity in vitro. Thus the processed extract of RP-Mount Tai may play a dual role in the inhibition of cell proliferation signaling by both chemical component and nanoscale herbzyme of phosphatase activity to inhibit kinases including mTOR/AKT in potent drug delivery of kinase inhibitors.

Salinity Affects Saxitoxins (STXs) Toxicity in the Dinoflagellate Alexandrium pacificum, with Low Transcription of SXT-Biosynthesis Genes sxtA4 and sxtG.

Salinity is an important factor for regulating metabolic processes in aquatic organisms; however, its effects on toxicity and STX biosynthesis gene responses in dinoflagellates require further elucidation. Herein, we evaluated the physiological responses, toxin production, and expression levels of two STX synthesis core genes, sxtA4 and sxtG, in the dinoflagellate Alexandrium pacificum Alex05 under different salinities (20, 25, 30, 35, and 40 psu). Optimal growth was observed at 30 psu (0.12 cell division/d), but cell growth significantly decreased at 20 psu and was irregular at 25 and 40 psu. The cell size increased at lower salinities, with the highest size of 31.5 µm at 20 psu. STXs eq was highest (35.8 fmol/cell) in the exponential phase at 30 psu. GTX4 and C2 were predominant at that time but were replaced by GTX1 and NeoSTX in the stationary phase. However, sxtA4 and sxtG mRNAs were induced, and their patterns were similar in all tested conditions. PCA showed that gene transcriptional levels were not correlated with toxin contents and salinity. These results suggest that A. pacificum may produce the highest amount of toxins at optimal salinity, but sxtA4 and sxtG may be only minimally affected by salinity, even under high salinity stress.

An auxin signaling network translates low-sugar-state input into compensated cell enlargement in the fugu5 cotyledon.

In plants, the effective mobilization of seed nutrient reserves is crucial during germination and for seedling establishment. The Arabidopsis H+-PPase-loss-of-function fugu5 mutants exhibit a reduced number of cells in the cotyledons. This leads to enhanced post-mitotic cell expansion, also known as compensated cell enlargement (CCE). While decreased cell numbers have been ascribed to reduced gluconeogenesis from triacylglycerol, the molecular mechanisms underlying CCE remain ill-known. Given the role of indole 3-butyric acid (IBA) in cotyledon development, and because CCE in fugu5 is specifically and completely cancelled by ech2, which shows defective IBA-to-indoleacetic acid (IAA) conversion, IBA has emerged as a potential regulator of CCE. Here, to further illuminate the regulatory role of IBA in CCE, we used a series of high-order mutants that harbored a specific defect in IBA-to-IAA conversion, IBA efflux, IAA signaling, or vacuolar type H+-ATPase (V-ATPase) activity and analyzed the genetic interaction with fugu5-1. We found that while CCE in fugu5 was promoted by IBA, defects in IBA-to-IAA conversion, IAA response, or the V-ATPase activity alone cancelled CCE. Consistently, endogenous IAA in fugu5 reached a level 2.2-fold higher than the WT in 1-week-old seedlings. Finally, the above findings were validated in icl-2, mls-2, pck1-2 and ibr10 mutants, in which CCE was triggered by low sugar contents. This provides a scenario in which following seed germination, the low-sugar-state triggers IAA synthesis, leading to CCE through the activation of the V-ATPase. These findings illustrate how fine-tuning cell and organ size regulation depend on interplays between metabolism and IAA levels in plants.

Genetic interaction between F-box motif encoding YDR131C and retrograde signaling-related RTG1 regulates the stress response and apoptosis in Saccharomyces cerevisiae.

The retrograde signaling pathway is well conserved from yeast to humans, which regulates cell adaptation during stress conditions and prevents cell death. One of its components, RTG1 encoded Rtg1p in association with Rtg3p communicates between mitochondria, nucleus, and peroxisome during stress for adaptation, by regulation of transcription. The F-box motif protein encoded by YDR131C  constitutes a part of SCF Ydr131c -E3 ligase complex, with unknown function; however, it is known that retrograde signaling is modulated by the E3 ligase complex. This study reports epistasis interaction between YDR131C and RTG1, which regulates cell growth, response to genotoxic stress, decreased apoptosis, resistance to petite mutation, and cell wall integrity. The cells of ydr131cΔrtg1Δ genetic background exhibits growth rate improvement however, sensitivity to hydroxyurea, itraconazole antifungal agent and synthetic indoloquinazoline-based alkaloid (8-fluorotryptanthrin, RK64), which disrupts the cell wall integrity in Saccharomyces cerevisiae. The epistatic interaction between YDR131C and RTG1 indicates a link between protein degradation and retrograde signaling pathways.

Genistein improves systemic metabolism and enhances cold resistance by promoting adipose tissue beiging.

Genistein, a naturally occurring phytoestrogen and a member of the large class of compounds known as isoflavones, exerts protective effects in several diseases. Recent studies indicate that genistein plays a critical role in controlling body weight, obesity-associated insulin resistance, and metabolic disorders, but its target organs in reversing obesity and related pathological conditions remain unclear. In this study, we showed that mice supplemented with 0.2% genistein in a high-fat diet for 12 weeks showed enhanced metabolic homeostasis, including reduced obesity, improved glucose uptake and insulin sensitivity, and alleviated hepatic steatosis. We also observed a beiging phenomenon in the white adipose tissue and reversal of brown adipose tissue whitening in these mice. These changes led to enhanced resistance to cold stress. Altogether, our data suggest that the improved metabolic profile in mice treated with genistein is likely a result of enhanced adipose tissue function.

Osteoprotegerin prompts cardiomyocyte hypertrophy via autophagy inhibition mediated by FAK/BECLIN1 pathway.

AIM: It has been reported that Osteoprotegerin (OPG) induces cardiomyocyte hypertrophy, but the mechanism remains unclear. This study was to investigate the role of Focal Adhesion Kinase (FAK) pathway in the OPG induced hypertrophy in cultured cardiomyocytes. METHODS: The H9C2 line of rat cardiomyocytes were treated with OPG at different concentrations and the cellular hypertrophy was evaluated. Meanwhile, the activity of FAK and other the phosphorylation kinases were detected. Autophagy flux assay was performed in absence and presence OPG. The interaction between proteins was analyses using Co-Immunoprecipitation assay. RESULTS: We found that OPG induced cardiomyocyte hypertrophic response, indicated by increased cellular size and protein content per cell. OPG increases the heart/body weight ratio in vivo. Also OPG inhibits autophagy and induces FAK phosphorylation. FAK silencing using si-RNA abrogates the effect of OPG on autophagy and cellular hypertrophy. Furthermore, Co-immunoprecipitation assay reveals that OPG inhibits autophagy through enhancing the binding of FAK and Beclin1. CONCLUSION: The FAK/Beclin1 signal pathway is essential for the OPG induced autophagy inhibition and hypertrophic response in cultured H9C2 cells.

Concentrations of homocysteine in follicular fluid and embryo quality and oocyte maturity in infertile women: a prospective cohort.

Homocysteine is one of the components of follicular fluid (FF), so that any disruptions in its concentration may affect oocyte development. The aim of this study was to determine the relationship between FF homocysteine concentration and embryo quality, oocyte maturity, and pregnancy rate. Oocytes and embryos of 44 infertile women were categorised into different groups based on their maturity and quality, respectively. FF homocysteine levels, oocyte maturity, embryo quality, and pregnancy status were measured. A significant association was observed between the levels of FF homocysteine ​and oocyte maturation rate (p = .00). The concentration of FF homocysteine was higher than 9.8 µm/L in women with oocyte maturation < 80%. Most of the good quality embryos belonged to homocysteine levels < 9.8 µm/L. Decreased FF homocysteine concentrations can significantly improve the oocyte maturation rate and embryo quality. Aging may be an indirect factor contributing to decreased embryo quality and oocyte maturation through increasing FF homocysteine levels.IMPACT STATEMENTWhat is already known on this subject? It has been demonstrated that homocysteine is one of the components of follicular fluid (FF), but no information is available about the link between its concentration in FF and oocyte development.What do the results of this study add? The data indicated that decreased FF homocysteine concentrations at a younger age may remarkably improve the oocyte maturity and embryo quality of infertile patients undergoing assisted reproductive treatment (ART).What are the implications of these findings for clinical practice and/or further research? Based on the findings and considering the ease of measuring serum homocysteine and its direct correlation with FF homocysteine, homocysteine level measurement is recommended in patients who are candidates for infertility treatment in order to estimate oocyte maturation rate, embryo quality, and ART outcomes. Future studies are suggested to investigate patients with PCOS, endometriosis, and male factor infertility.

Effect of e-cigarettes on nasal epithelial cell growth, Ki67 expression, and pro-inflammatory cytokine secretion.

OBJECTIVE: Upon use, e-cigarette aerosol comes in contact with various mucosal tissues, including the nasal epithelium, which may lead to nasal pathologies. We therefore assessed the effect of e-cigarettes on nasal epithelial cell and tissue behaviours. METHODS: Human primary nasal epithelial cells and engineered 3D nasal mucosa tissues were exposed or not to either e-cigarette aerosol or standard cigarette smoke. We then evaluated cell viability and lactate dehydrogenase (LDH) activity. With the tissues analysed tissue structure, the expression of Ki67 proliferating marker, and the secretion of pro-inflammatory cytokines by the engineered nasal mucosa. RESULTS: The nasal epithelial cells exposed to e-cigarettes displayed a larger cell size and a faint nucleus following exposure to e-cigarettes. This is supported by the increased levels of LDH activity following exposure to e-cigarettes, compared to that observed in the control. Tissues exposed to e-cigarette aerosol displayed a structural deregulation, with more large-sized cells, fewer Ki67-positive cells, and a reduced proliferation rate, compared to that observed in the non-exposed tissues. Cytokine measurements showed high levels of IL-6, IL-8, TNFα, and MCP-1, demonstrating that e-cigarettes activated pro-inflammatory cytokine responses. CONCLUSION: E-cigarette aerosol showed adverse effects on nasal epithelial cells and nasal engineered mucosa tissue. These findings indicate that e-cigarettes could be a threat to nasal tissues and may impair the innate immune function of nasal epithelial cells.

Swietenine extracted from Swietenia relieves myocardial hypertrophy induced by isoprenaline in mice.

As a traditional plant medicine in tropical areas, Swietenia macrophylla seeds are usually applied for some chronic diseases, including hypertension, diabetes, and so on. Few studies have been carried out to identify the effective elements in seed extract and their indications. In this study, we first investigated the functions of the swietenine, an extract from S. macrophylla seeds, using a model of myocardial hypertrophy induced by isoprenaline (ISO). At cellular level, H9c2 cell hypertrophy was also established through the treatment with ISO. The cardiac pathological remodeling was evaluated by echocardiography and histological analysis. Western blot and RT-qPCR were used to detect the expression of possible hypertrophy-promoting genes. Here, our results indicated that swietenine remarkably attenuated ISO-induced myocardial hypertrophy in vivo and in vitro. Moreover, Akt phosphorylation, ANP and BNP mRNA expression were efficiently decreased. Based on these findings, we concluded that swietenine might be a promising anti-hypertrophic agent against cardiac hypertrophy.

Danshen (Salvia miltiorhiza) inhibits Leu27 IGF-II-induced hypertrophy in H9c2 cells.

In this study, we used ICI 182 780 (ICI), an estrogen receptor (ER) antagonist, to investigate the estrogenic activity of Danshen, and to further explored whether Danshen extract can block Leu27IGF-II-induced hypertrophy in H9c2 cardiomyoblast cells. We first used an IGF-II analog Leu27IGF-II, which specifically activates IGF2R signaling cascades and induces H9c2 cardiomyoblast cell hypertrophy. However, Danshen extract completely inhibited Leu27IGF-II-induced cell size increase, ANP and BNP hypertrophic marker expression, and IGF2R induction. We also observed that Danshen extract inhibited calcineurin protein expression and NFAT3 nuclear translocation, leading to suppression of Leu27IGF-II-induced cardiac hypertrophy. Moreover, the anti-Leu27IGF-II-IGF2R signaling effect of Danshen was totally reversed by ICI, which suggest the cardio protective effect of Danshen is mediated through estrogen receptors. Our study suggests that, Danshen exerts estrogenic activity, and thus, it could be used as a selective ER modulator in IGFIIR induced hypertrophy model.

Auxin treatment of grapevine (Vitis vinifera L.) berries delays ripening onset by inhibiting cell expansion.

KEY MESSAGE: Auxin treatment of grape (Vitis vinifera L.) berries delays ripening by inducing changes in gene expression and cell wall metabolism and could combat some deleterious climate change effects. Auxins are inhibitors of grape berry ripening and their application may be useful to delay harvest to counter effects of climate change. However, little is known about how this delay occurs. The expression of 1892 genes was significantly changed compared to the control during a 48 h time-course where the auxin 1-naphthaleneacetic acid (NAA) was applied to pre-veraison grape berries. Principal component analysis showed that the control and auxin-treated samples were most different at 3 h post-treatment when approximately three times more genes were induced than repressed by NAA. There was considerable cross-talk between hormone pathways, particularly between those of auxin and ethylene. Decreased expression of genes encoding putative cell wall catabolic enzymes (including those involved with pectin) and increased expression of putative cellulose synthases indicated that auxins may preserve cell wall structure. This was confirmed by immunochemical labelling of berry sections using antibodies that detect homogalacturonan (LM19) and methyl-esterified homogalacturonan (LM20) and by labelling with the CMB3a cellulose-binding module. Comparison of the auxin-induced changes in gene expression with the pattern of these genes during berry ripening showed that the effect on transcription is a mix of changes that may specifically alter the progress of berry development in a targeted manner and others that could be considered as non-specific changes. Several lines of evidence suggest that cell wall changes and associated berry softening are the first steps in ripening and that delaying cell expansion can delay ripening providing a possible mechanism for the observed auxin effects.

The effects of L-NAME on DU145 human prostate cancer cell line: A cytotoxicity-based study.

Of all cancer types, prostate cancer is the second most common one with an age-standardized incidence rate of 29.3 per 100,000 men worldwide. Nitric oxide (NO) is both a radical and versatile messenger molecule involved in many physiological activities. NO was documented to be highly secreted and utilized by cancer cells. Nω-nitro-L-arginine methyl ester (L-NAME) is utilized for inhibiting NO synthase. Its worst long-term side effect is reported to be hypertension, hence less cytotoxic than chemotherapeutic agents. Herein, we carried out a cytotoxicity study on how different doses of L-NAME affect DU145 human prostate cancer cells. First, toxic doses of L-NAME were determined. Then, while antioxidant capacity was determined by glutathione and total antioxidant status, oxidative stress was evaluated by quantifying malondialdehyde, NO, and total oxidant status levels. Inflammatory effects of L-NAME were investigated by measuring tumor necrosis factor-α and interleukin-6 (IL-6) levels. Apoptotic effects of L-NAME were evaluated by measuring cytochrome C somatic and caspase 3 levels and by staining Bax protein. Finally, morphological analysis was performed. IC50 of L-NAME against DU145 cells was 12.2 mM. In L-NAME-treated DU145 cells, a dose-dependent increase in oxidative stress, inflammatory, and apoptotic marker proteins and decrease in antioxidant capacity were observed. While at the moderate dose of L-NAME, apoptotic changes were commonly observed, at higher doses, vacuolated and swollen cells were also recorded. We believe that the present study will encourage future studies by providing insights about dose and effects of L-NAME.

Extracellular transglutaminase 2 induces myotube hypertrophy through G protein-coupled receptor 56.

Skeletal muscle secretes biologically active proteins that contribute to muscle hypertrophy in response to either exercise or dietary intake. The identification of skeletal muscle-secreted proteins that induces hypertrophy can provide critical information regarding skeletal muscle health. Dietary provitamin A, ß-carotene, induces hypertrophy of the soleus muscle in mice. Here, we hypothesized that skeletal muscle produces hypertrophy-inducible secretory proteins via dietary ß-carotene. Knockdown of retinoic acid receptor (RAR) γ inhibited the ß-carotene-induced increase soleus muscle mass in mice. Using RNA sequencing, bioinformatic analyses, and literature searching, we predicted transglutaminase 2 (TG2) to be an all-trans retinoic acid (ATRA)-induced secretory protein in cultured C2C12 myotubes. Tg2 mRNA expression increased in ATRA- or ß-carotene-stimulated myotubes and in the soleus muscle of ß-carotene-treated mice. Knockdown of RARγ inhibited ß-carotene-increased mRNA expression of Tg2 in the soleus muscle. ATRA increased endogenous TG2 levels in conditioned medium from myotubes. Extracellular TG2 promoted the phosphorylation of Akt, mechanistic target of rapamycin (mTOR), and ribosomal p70 S6 kinase (p70S6K), and inhibitors of mTOR, phosphatidylinositol 3-kinase, and Src (rapamycin, LY294002, and Src I1, respectively) inhibited TG2-increased phosphorylation of mTOR and p70S6K. Furthermore, extracellular TG2 promoted protein synthesis and hypertrophy in myotubes. TG2 mutant lacking transglutaminase activity exerted the same effects as wild-type TG2. Knockdown of G protein-coupled receptor 56 (GPR56) inhibited the effects of TG2 on mTOR signaling, protein synthesis, and hypertrophy. These results indicated that TG2 expression was upregulated through ATRA-mediated RARγ and that extracellular TG2 induced myotube hypertrophy by activating mTOR signaling-mediated protein synthesis through GPR56, independent of transglutaminase activity.

The first study on the impact of osmolytes in whole cells of high temperature-adapted microorganisms.

The hyperthermophilic piezophile, Thermococcus barophilus displays a strong stress response characterized by the accumulation of the organic osmolyte, mannosylglycerate during growth under sub-optimal pressure conditions (0.1 MPa). Taking advantage of this known effect, the impact of osmolytes in piezophiles in an otherwise identical cellular context was investigated, by comparing T. barophilus cells grown under low or optimal pressures (40 MPa). Using neutron scattering techniques, we studied the molecular dynamics of live cells of T. barophilus at different pressures and temperatures. We show that in the presence of osmolytes, cells present a higher diffusion coefficient of hydration water and an increase of bulk water motions at a high temperature. In the absence of osmolytes, the T. barophilus cellular dynamics is more responsive to high temperature and high hydrostatic pressure. These results therefore give clear evidence for a protecting effect of osmolytes on proteins.

Effect of oblique polymer pillars on spreading and elongation of rat mesenchymal stem cells.

Stiffness and anisotropy of culture substrates are important factors influencing the cell behavior and their responses to external stimuli. Herein, we report a fabrication method of oblique polymer pillars which allow modulating both stiffness and anisotropy of the substrate for spreading and elongation studies of Rat Mesenchymal Stem Cells (RMSCs). Poly (Lactic-co-Glycolic Acid) (PLGA) has been chosen to produce micro-pillars of different heights and different pitches using a combined method of soft-lithography and hot embossing. The stiffness of such pillar substrates varies over a large range so that RMSCs show effectively different spreading behaviors which are also sensitive to the inclining angle of the pillars. Our results showed that with the increase of the pillar height the area of cell spreading decreases but the cell elongation aspect ratio increases. Moreover, cells preferentially elongate along the direction perpendicular to that of the pillars' inclining, which is in agreement with the calculated anisotropy of the pillar substrate stiffness.

Arsenic trioxide inhibits angiogenesis in vitro and in vivo by upregulating FoxO3a.

Arsenic trioxide (As2O3) has been used clinically for the treatment of acute promyelocytic leukemia and some solid tumors. However, the mechanisms of its anti-tumor effects are still elusive. Angiogenesis is a key process for tumor initiation, and increasing evidence has supported the role of anti-angiogenesis caused by arsenic in tumor suppression, although the detailed mechanism is not well understood. In the present study, we found that As2O3 significantly inhibited the angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro, and this was mediated by the upregulation of FoxO3a. Knockdown of FoxO3a could restore the angiogenic ability of HUVECs. Moreover, vascular endothelial cell-specific knockout of FoxO3a in mice could disrupt the anti-angiogenesis effect of As2O3 and endow the tumors with resistance to As2O3 treatments. Our results revealed a new mechanism by which As2O3 suppresses angiogenesis and tumor growth.

ERK1/2 communicates GPCR and EGFR signaling pathways to promote CTGF-mediated hypertrophic cardiomyopathy upon Ang-II stimulation.

BACKGROUND: Hypertrophic cardiomyopathy occurs along with pathological phenomena such as cardiac hypertrophy, myocardial fibrosis and cardiomyocyte activity. However, few of the specific molecular mechanisms underlying this pathological condition have been mentioned. METHODS: All target proteins and markers expression in the study was verified by PCR and western bloting. H9c2 cell morphology and behavior were analyzed using immunofluorescent and proliferation assays, respectively. And, the CTGF protein secreted in cell culture medium was detected by ELISA. RESULTS: We found that high expression of CTGF and low expression of EGFR were regulated by ERK1/2 signaling pathway during the cardiac hypertrophy induced by Ang-II stimulation. CTGF interacted with EGFR, and the interaction is reduced with the stimulation of Ang-II. ERK1/2 serves as the center of signal control during the cardiac hypertrophy. CONCLUSION: The ERK1/2 cooperates with GPCR and EGFR signaling, and promotes the occurrence and development of cardiac hypertrophy by regulating the expression and binding states of CTGF and EGFR. The study revealed a regulation model based on ERK1/2, suggesting that ERK1/2 signaling pathway may be an important control link for mitigation of hypertrophic cardiomyopathy treatment.

Cafestol Activates Nuclear Factor Erythroid-2 Related Factor 2 and Inhibits Urotensin II-Induced Cardiomyocyte Hypertrophy.

Through population-based studies, associations have been found between coffee drinking and numerous health benefits, including a reduced risk of cardiovascular disease. Active ingredients in coffee have therefore received considerable attention from researchers. A wide variety of effects have been attributed to cafestol, one of the major compounds in coffee beans. Because cardiac hypertrophy is an independent risk factor for cardiovascular events, this study examined whether cafestol inhibits urotensin II (U-II)-induced cardiomyocyte hypertrophy. Neonatal rat cardiomyocytes were exposed only to U-II (1 nM) or to U-II (1 nM) following 12-h pretreatment with cafestol (1-10 µ M). Cafestol (3-10 µ M) pretreatment significantly inhibited U-II-induced cardiomyocyte hypertrophy with an accompanying decrease in U-II-induced reactive oxygen species (ROS) production. Cafestol also inhibited U-II-induced phosphorylation of redox-sensitive extracellular signal-regulated kinase (ERK) and epidermal growth factor receptor transactivation. In addition, cafestol pretreatment increased Src homology region 2 domains-containing phosphatase-2 (SHP-2) activity, suggesting that cafestol prevents ROS-induced SHP-2 inactivation. Moreover, nuclear factor erythroid-2-related factor 2 (Nrf2) translocation and heme oxygenase-1 (HO-1) expression were enhanced by cafestol. Addition of brusatol (a specific inhibitor of Nrf2) or Nrf2 siRNA significantly attenuated cafestol-mediated inhibitory effects on U-II-stimulated ROS production and cardiomyocyte hypertrophy. In summary, our data indicate that cafestol prevented U-II-induced cardiomycyte hypertrophy through Nrf2/HO-1 activation and inhibition of redox signaling, resulting in cardioprotective effects. These novel findings suggest that cafestol could be applied in pharmacological therapy for cardiac diseases.

A Chemical Inhibitor of Cell Growth Reduces Cell Size in Bacillus subtilis.

Bacteria exhibit complex responses to biologically active small molecules. These responses include reductions in transcriptional and translational efficiency, alterations in metabolic flux, and in some cases, dramatic changes in growth and morphology. Here, we describe Min-1, a novel small molecule that inhibits growth of Gram-positive bacteria by targeting the cell envelope. Subinhibitory levels of Min-1 inhibits sporulation in Streptomyces venezuelae and reduces growth rate and cell length in Bacillus subtilis. The effect of Min-1 on B. subtilis cell length is significant at high growth rates sustained by nutrient-rich media but drops off when growth rate is reduced during growth on less energy-rich carbon sources. In each medium, Min-1 has no impact on the proportion of cells containing FtsZ-rings, suggesting that Min-1 reduces the mass at which FtsZ assembly is initiated. The effect of Min-1 on size is independent of UDP-glucose, which couples cell division to carbon availability, and the alarmone ppGpp, which reduces cell size via its impact on fatty acid synthesis. Min-1 activates the LiaRS stress response, which is sensitive to disruptions in the lipid II cycle and the cell membrane, and also compromises cell membrane integrity. Therefore, this novel synthetic molecule inhibits growth at high concentrations and induces a short-cell phenotype at subinhibitory concentrations that is independent of known systems that influence cell length, highlighting the complex interactions between small molecules and cell morphology.