Inhibitory effect of trilinolein on angiotensin II-induced cardiomyocyte hypertrophy

Targeting mitochondrial dysfunction in atopic dermatitis with trilinolein: A triacylglycerol from the medicinal plant Cannabis fructus

BACKGROUND

Atopic dermatitis (AD) is a common skin condition that causes chronic and recurring eczema lesions. Prior research has indicated that Cannabis fructus, the mature fruit of Cannabis sativa, has an antioxidant effect. Historically, Cannabis fructus has been used in cosmetics and medicine. However, there is limited knowledge regarding its biological components and the mechanisms by which it prevents and treats AD.

OBJECTIVES

HPLC-ESI-MS/MS analysis was utilized to identify the main compounds of Cannabis fructus, and trilinolein was extracted using chromatographic techniques. The potential of trilinolein in the prevention of AD was assessed, and its underlying mechanisms of action were elucidated.

METHODS

The distribution of distinct cellular subpopulations and the principal biological processes implicated in the pathogenesis of AD were assessed through a comparative study involving chronic AD patients and healthy controls (HCs). Differential gene expression was validated in clinical samples from the lesions of AD patients and the healthy skin of controls. The pharmacodynamic activity of trilinolein was validated in dinitrochlorobenzene (DNCB)-induced BALB/c mice and in IL-4- and TNF-α-induced HaCaT cells. Proteomics analyse was employed to investigate its mechanisms.

RESULTS

Single-cell transcriptome analysis revealed that chronic AD is characterized by abnormal keratinocyte differentiation and oxidative stress damage. When topically applied, trilinolein can effectively improve AD-like skin lesions induced by DNCB. It increases the expression of terminal differentiation proteins and decreases the expression of NADPH oxidase 2 (NOX2), with a therapeutic effect comparable to that of the positive control drug crisaborole. Additionally, trilinolein reduced ROS fluorescence intensity, restored mitochondrial morphology and membrane potential, and decreased mitochondrial DNA (mtDNA) release in keratinocytes stimulated with IL-4 and TNF-α. Moreover, trilinolein increased the protein expression of AhR, CYP1A1, and Nrf2 in a dose-dependent manner. The effect of trilinolein on keratinocyte terminal differentiation proteins and ROS levels was blocked by the addition of an AhR inhibitor.

CONCLUSION

The study suggests that trilinolein from Cannabis fructus alleviates NOX2-dependent mitochondrial dysfunction and repair the skin barrier via AhR-Nrf2 pathway, making it a promising agent for the prevention and treatment of AD.

Treatment of the cardiac hypertrophic response and heart failure with ginseng, ginsenosides, and ginseng-related products

Heart failure is a major medical and economic burden throughout the world. Although various treatment options are available to treat heart failure, death rates in both men and women remain high. Potential adjunctive therapies may lie with use of herbal medications, many of which possess potent pharmacological properties. Among the most widely studied is ginseng, a member of the genus Panax that is grown in many parts of the world and that has been used as a medical treatment for a variety of conditions for thousands of years, particularly in Asian societies. There are a number of ginseng species, each possessing distinct pharmacological effects due primarily to differences in their bioactive components including saponin ginsenosides and polysaccharides. While experimental evidence for salutary effects of ginseng on heart failure is robust, clinical evidence is less so, primarily due to a paucity of large-scale well-controlled clinical trials. However, there is evidence from small trials that ginseng-containing Chinese medications such as Shenmai can offer benefit when administered as adjunctive therapy to heart failure patients. Substantial additional studies are required, particularly in the clinical arena, to provide evidence for a favourable effect of ginseng in heart failure patients.

Medicinal effect and its JP2/RyR2-based mechanism of Smilax glabra flavonoids on angiotensin II-induced hypertrophy model of cardiomyocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizome and root of Smilax glabra Roxb (Liliaceae family) is a widely used traditional Chinese medicine (TCM) named Tu-fu-ling (TFL) for cardiac disease therapy. The TFL flavonoids (TFLF) has been extracted and proven to possess the anti-cardiac hypertrophy effect in our previous reports. Such effect could be mediated by the modulation of intracellular Ca(2+) flux in myocardial cells, in which junctophilin-2 (JP2) and ryanodine receptor 2 (RyR2) play an important role. However, its mechanism of the anti-cardiac hypertrophy effect remains unclarified.

MATERIALS AND METHODS

2μmol/L Ang II was applied to induce hypertrophy model of rat primary cardiomyocytes. After treatment of TFLF at 0.25, 0.5 and 1.0mg/ml, the cell size was microscopic measured, and the protein and mRNA expressions of JP2 and RyR2 in cardiomyocytes were estimated by immunofluorescence imaging, ELISA and real-time PCR assay.

RESULTS

Obvious hypertrophy of cardiomyocytes was induced by Ang II but reversed by TFLF from 0.5 to 1.0mg/ml. The protein and mRNA expressions of JP2 and RyR2 in cardiomyocytes were also inhibited by Ang II but restored by TFLF at its dose range. Such effect of TFLF was exerted at a dose dependent manner, which was even better than that of verapamil.

CONCLUSIONS

Our findings may evidence the correlation between JP2/RyR2 and myocardiac hypertrophy, and indicate the JP2/RyR2-mediated anti-hypertrophy mechanism of TFLF for the first time. It deserves to be developed as a promising TCM candidate of new drug for myocardial hypertrophy treatment.

Morton lentil extract attenuated angiotensin II-induced cardiomyocyte hypertrophy via inhibition of intracellular reactive oxygen species levels in vitro

The objective was to investigate whether a lentil (Morton) extract had any protective effect on cardiac hypertrophy, which is one of the most significant sequelae of cardiovascular diseases. High phenolic compounds (43.4 mg of GAE/g), including thirteen phenolic acid and two flavonoids, were detected in the acetone/water/acetic acid lentil extract. The extract showed strong antioxidant ability (105 μmol of TE/g). The effect of lentil extract on angiotensin (Ang) II-induced cardiac hypertrophy was examined. Results showed that pretreatment with lentil extract (25, 50, 100 μg/mL) significantly attenuated Ang II (0.1 μM)-induced hypertrophy by 18, 28, and 36% in rat cardiomycytes, respectively; lentil extract (12.5, 25, 50 μg/mL) attenuated Ang II (0.1 μM)-induced hypertrophy by 9, 17, and 25% in human cardiomycytes, respectively. Intracellular reactive oxygen species (ROS) levels were enhanced by Ang II treatment, and this stimulatory action was significantly attenuated (33% inhibition) by lentil extract (100 μg/mL) in rat cardiomyocytes and attenuated by 22% by 50 μg/mL lentil extract in human cardiomyocytes. In conclusion, Morton lentil extracts attenuated Ang II-induced rat and human cardiomyocytes hypertrophy via decreasing intracellular ROS levels.

An essential role of Nrf2 in American ginseng-mediated anti-oxidative actions in cardiomyocytes

AIM OF THE STUDY

Ginseng has been used as a folk medicine for thousands of years in Asia, and has become a popular herbal medicine world-wide. Recent studies have revealed that ginseng, including American ginseng, exerts antioxidant effects in the cardiovascular system; however, the underlying mechanisms are not fully understood. Thus, we investigated role of Nrf2, a master transcription factor of endogenous anti-oxidative defense systems, in the regulation of American ginseng-mediated anti-oxidative actions in cardiomyocytes.

MATERIALS AND METHODS

A standardized crude extract of American ginseng was supplied by the National Research Council of Canada, Institute for National Measurement Standards. H9C2 cells, a rat cardiomyocyte cell line, were exposed to angiotensin II (Ang II) or tumor necrosis factor alpha (TNFalpha) to induce oxidative stress that was examined by measuring formation of reactive oxygen and nitrogen species. Oxidative stress-induced cell death was induced by exogenous addition of hydrogen peroxide (H(2)O(2)). Proteins were measured by Western blot and mRNA expression was determined by quantitative real time PCR. Nrf2-driven transcriptional activity was assessed by antioxidant response element (ARE)-luciferase reporter assay. Direct Nrf2 binding to its target gene promoters was determined by chromatin immunoprecipitation assay. Adenoviral over-expression of Nrf2 shRNA was utilized to knock down Nrf2 in H9C2 cells. Immunochemical staining was applied for Nrf2 expression in the heart.

RESULTS

American ginseng induced dramatic increases in Nrf2 protein expression, Nrf2 nuclear translocation, Nrf2 transcriptional activity, direct Nrf2 binding to its target gene promoters, and expression of a group of anti-oxidative genes driven by Nrf2 in H9C2 cells. In addition, American ginseng inhibited Ang II- or TNFalpha-induced free radical formation and H(2)O(2)-induced cell death in H9C2 cells over-expressed with control shRNA but not in the cells over-expressed with Nrf2 shRNA. Finally, oral administration of American ginseng markedly increased Nrf2 activity in murine hearts.

CONCLUSION

These results demonstrate that American ginseng suppresses oxidative stress and oxidative stress-induced cell death in cardiomyocytes through activating the Nrf2 pathway, thereby providing cardioprotection against pathological cardiac remodeling.

Pharmacological activity of sanchi ginseng (Panax notoginseng)

The pharmacological activity and constituents of the sanchi ginseng Panax notoginseng have been reviewed. The bulk of pharmacological findings have been based on the saponins or steryl glycosides, although polysaccharides with immunopotentiating activity, proteins with antifungal, ribonuclease and xylanase activity, and a triacylglycerol (trilinolein) with antioxidant activity have been reported. Protective actions against cerebral ischaemia, beneficial effects on the cardiovascular system, and haemostatic, antioxidant, hypolipidaemic, hepatoprotective, renoprotective and estrogen-like activities have been described. Various methods for authentication of P. notoginseng are available.

Redox-dependent protein kinase regulation by angiotensin II: mechanistic insights and its pathophysiology

Reactive oxygen species (ROS) are proposed to induce cardiovascular diseases, such as atherosclerosis, hypertension, restenosis, and fibrosis, through several mechanisms. One such mechanism involves ROS acting as intracellular second messengers, which lead to induction of unique signal transductions. Angiotensin II (AngII), a potent cardiovascular pathogen, stimulates ROS production through the G protein-coupled AngII type 1 receptor expressed in its target organs, such as vascular tissues, heart, and kidney. Recent accumulating evidence indicates that through ROS production, AngII activates downstream ROS-sensitive kinases that are critical in mediating cardiovascular remodeling. Each of these ROS-sensitive kinases could potentially mediate its own specific function. In this review, we will focus our discussion on the current findings that suggest novel mechanisms of how AngII mediates activation of these redox-sensitive kinases in target organs, as well as the pathological significance of their activation.

Role of myofibrillogenesis regulator-1 in myocardial hypertrophy

Myofibrillogenesis regulator-1 (MR-1) is a novel homologous gene, identified from a human skeletal muscle cDNA library, that interacts with contractile proteins and exists in human myocardial myofibrils. The present study investigated MR-1 protein expression in hypertrophied myocardium and MR-1 involvement in cardiac hypertrophy. Cardiac hypertrophy was induced by abdominal aortic stenosis (AAS) in Sprague-Dawley rats. Left ventricular (LV) hypertrophy was assessed by the ratio of LV wet weight to whole heart weight (LV/HW) or LV weight to body weight (LV/BW). Rat MR-1 (rMR-1) expression in the myocardium was detected by immunohistochemical and Western blotting analysis. Hypertrophy was induced by ANG II incubation in cultured neonatal rat cardiomyocytes. The effect of rMR-1 RNA interference on ANG II-induced hypertrophy was studied by transfection of cardiomyocytes with an RNA interference plasmid, pSi-1, which targets rMR-1. Hypertrophy in cardiomyocytes was assessed by [3H]Leu incorporation and myocyte size. rMR-1 protein expression in cardiomyocytes was detected by Western blotting. We found that AAS resulted in a significant increase in LV/HW and LV/BW: 89% and 86%, respectively (P < 0.01). Immunohistochemistry and Western blot analysis demonstrated upregulated rMR-1 protein expression in hypertrophic myocardium. ANG II induced a 24% increase in [3H]Leu incorporation and a 65.8% increase in cell size compared with control cardiomyocytes (P < 0.01), which was prevented by treatment with losartan, an angiotensin (AT1) receptor inhibitor, or transfection with pSi-1. rMR-1 expression increased in ANG II-induced hypertrophied cardiomyocytes, and pSi-1 transfection abolished the upregulation. These findings suggest that MR-1 is associated with cardiac hypertrophy in rats in vivo and in vitro.

Inhibitory effect of trilinolein on endothelin-1-induced c-fos gene expression in cultured neonatal rat cardiomyocytes

Trilinolein, isolated from the traditional Chinese herb Sanchi (Panax notoginseng), has been shown to have myocardial protective effects via its antioxidant ability. However, the cellular and molecular mechanisms of the protective effect of trilinolein in the heart remain to be elucidated. Oxidative mechanisms have been implicated in neonatal cardiomyocyte hypertrophy. We previously reported that ET-1 induces ROS generation via the ET(A) receptor and ROS modulates c-fos gene expression. We have therefore examined whether trilinolein attenuates ROS production and ET-1-induced c-fos gene expression in cardiomyocytes. Cultured neonatal rat cardiomyocytes were stimulated with ET-1 (10 nM), and c-fos gene expression was examined. Trilinolein (1 and 10 microM) inhibited ET-1-induced c-fos gene expression in cardiomyocytes. We also examined the effects of trilinolein on ET-1-increased NADPH oxidase activity and superoxide formation. Trilinolein inhibited ET-1-increased NADPH oxidase activity and superoxide formation in a concentration-dependent manner. This increase in superoxide production by ET-1 was significantly inhibited by trilinolein, diphenyleneiodonium, or N-acetylcysteine. Trilinolein also decreased ET-1- or H2O2-induced extracellular signal-regulated kinase (ERK) phosphorylation, c-Jun NH2-terminal kinase (JNK) phosphorylation, and activator protein-1 activation. These data indicate that trilinolein inhibits ET-1-induced ERK phosphorylation, JNK phosphorylation, and c-fos gene expression via attenuating superoxide production in cardiomyocytes.

Role of mitogen-activated protein kinase pathway in reactive oxygen species-mediated endothelin-1-induced beta-myosin heavy chain gene expression and cardiomyocyte hypertrophy

Endothelin-1 (ET-1) has been found to increase cardiac beta-myosin heavy chain (beta-MyHC) gene expression and induce hypertrophy in cardiomyocytes. ET-1 has been demonstrated to increase intracellular reactive oxygen species (ROS) in cardiomyocytes. The exact molecular mechanism by which ROS regulate ET-1-induced beta-MyHC gene expression and hypertrophy in cardiomyocytes, however, has not yet been fully described. We aim to elucidate the molecular regulatory mechanism of ROS on ET-1-induced beta-MyHC gene expression and hypertrophic signaling in neonatal rat cardiomyocytes. Following stimulation with ET-1, cultured neonatal rat cardiomyocytes were examined for 3H-leucine incorporation and beta-MyHC promoter activities. The effects of antioxidant pretreatment on ET-1-induced cardiac hypertrophy and mitogen-activated protein kinase (MAPKs) phosphorylation were studied to elucidate the redox-sensitive pathway in cardiomyocyte hypertrophy and beta-MyHC gene expression. ET-1 increased 3H-leucine incorporation and beta-MyHC promoter activities, which were blocked by the specific ET(A) receptor antagonist BQ-485. Antioxidants significantly reduced ET-1-induced 3H-leucine incorporation, beta-MyHC gene promoter activities and MAPK (extracellular signal-regulated kinase, p38, and c-Jun NH2 -terminal kinase) phosphorylation. Both PD98059 and SB203580 inhibited ET-1-increased 3H-leucine incorporation and beta-MyHC promoter activities. Co-transfection of the dominant negative mutant of Ras, Raf, and MEK1 decreased the ET-1-induced beta-MyHC promoter activities, suggesting that the Ras-Raf-MAPK pathway is required for ET-1 action. Truncation analysis of the beta-MyHC gene promoter showed that the activator protein-2 (AP-2)/specificity protein-1 (SP-1) binding site(s) were(was) important cis-element(s) in ET-1-induced beta-MyHC gene expression. Moreover, ET-1-induced AP-2 and SP-1 binding activities were also inhibited by antioxidant. These data demonstrate the involvement of ROS in ET-1-induced hypertrophic responses and beta-MyHC expression. ROS mediate ET-1-induced activation of MAPK pathways, which culminates in hypertrophic responses and beta-MyHC expression.