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Heart failure remains a common cause of hospitalization and death worldwide. Heart failure can be caused by dysregulation of gene expression following abnormal expression of histone modifying enzymes. While lysine acetylation and methylation of histones have been the topic of many investigations, the role of arginine methylation in H3 has been overlooked. In an effort to understand regulatory mechanisms implicated in cardiac hypertrophy and heart failure, we assessed protein arginine methyl transferase (PRMT) members in the left ventricle of failing human hearts and control hearts. Our results show a specific up-regulation of PRMT6 mRNA in failing human hearts (5.95±2.16 fold in failing versus control, p=0.003) which also occurs in the compensatory phase of cardiac hypertrophy in mouse hearts subjected to pressure overload hypertrophy, and in neonatal rat ventricular myocytes (NRVM) stimulated with the hypertrophic agonist phenylephrine (PE). These changes are associated with a significant increase in arginine 2 asymmetric methylation of H3 (H3R2me2a) and reduced lysine 3 tri-methylation of H3 (H3K4me3) both in NRVM and in vivo . Importantly, forced expression of PRMT6 in NRVM stimulated with PE, enhances the expression of atrial natriuretic peptide (ANP). Conversely, silencing of PRMT6 reduces ANP protein expression and cell size, indicating that PRMT6 is critical for PE-mediated cardiac hypertrophy of NRVM. Also, silencing of PRMT6 reduces H3R2me2a, a mark associated with transcriptional repression. To evaluate the role of PRMT6 on cardiac contractility and global ion channel activity, we assessed contractility and global field potentials in live NRVM expressing normal and low level PRMT6 using the RTCA CardioECR system (ACEA Bioscience Inc.). Strikingly, reduced expression of PRMT6 drastically inhibits the contraction rate of NRVM, which is paralleled by a slight increase in the QT interval. All together, our results indicate that PRMT6 is a critical regulator of cardiac hypertrophy, implicating H3R2me2a as an important histone modification. Future studies investigating the specific gene programs regulated by PRMT6 are on their way. This study may help identify novel points of control to design new drugs for the treatment of heart failure.

Mast cells play an important role in immunomodulation and in the maintenance of vascular integrity. Interleukin-6 (IL-6) is one of the key biomarkers and therapeutic target in systemic vasculitis. The objective of the current study is to describe the role of mast cells in arterial IL-6 homeostasis. Eight- to ten-week-old male C57BL/6 (wild-type) mice were injected with either (a) saline, (b) compound 48/80 (a systemic mast cell degranulating agent), (c) lipopolysaccharide (LPS), or (d) a combination of C48/80 and LPS. Twenty-four hours after the injections, mice were sacrificed and serum samples and aortic tissues were analyzed for determining inflammatory response and cytokine expression profile. The results revealed that induction of mast cell degranulation significantly lowers serum IL-6 levels and aortic expression of IL-6 in LPS-treated mice. Significantly higher aortic expression of toll-like receptor-2 (TLR-2) and TNF-α was seen in the LPS and LPS+C48/80 groups of mice compared to controls. Aortic expression of TLR-4 was significantly decreased in LPS+C48/80 compared to C48/80 alone. LPS+C48/80-treated mice presented with a 3-fold higher aortic expression of suppressor of cytokine signaling (SOCS-1) compared to saline-injected groups. The inhibition of LPS-induced increase in serum IL-6 levels by mast cell degranulation was not seen in H1R knockout mice which suggests that mast cell-derived histamine acting through H1R may participate in the regulatory process. To examine whether the mast cell-mediated downregulation of LPS-induced IL-6 production is transient or cumulative in nature, wild-type mice were injected serially over a period of 10 days (5 injections) and serum cytokine levels were quantified. We found no significant differences in serum IL-6 levels between any of the groups. While mice injected with C48/80 or LPS had higher IL-10 compared to vehicle-injected mice, there was no difference between C48/80- and LPS+C48/80-injected mice. In conclusion, in an in vivo setting, mast cells appear to partially and transiently regulate systemic IL-6 homeostasis. This effect may be regulated through increased systemic IL-10 and/or aortic overexpression of SOCS-1.

Heart failure remains a major cause of hospitalization and death worldwide. Heart failure can be caused by abnormalities in the epigenome resulting from dysregulation of histone-modifying enzymes. While chromatin enzymes catalyzing lysine acetylation and methylation of histones have been the topic of many investigations, the role of arginine methyltransferases has been overlooked. In an effort to understand regulatory mechanisms implicated in cardiac hypertrophy and heart failure, we assessed the expression of protein arginine methyltransferases (PRMTs) in the left ventricle of failing human hearts and control hearts. Our results show a significant up-regulation of protein arginine methyltransferase 6 (PRMT6) in failing human hearts compared to control hearts, which also occurs in the early phase of cardiac hypertrophy in mouse hearts subjected to pressure overload hypertrophy induced by trans-aortic constriction (TAC), and in neonatal rat ventricular myocytes (NRVM) stimulated with the hypertrophic agonist phenylephrine (PE). These changes are associated with a significant increase in arginine 2 asymmetric methylation of histone H3 (H3R2Me2a) and reduced lysine 4 tri-methylation of H3 (H3K4Me3) observed both in NRVM and in vivo. Importantly, forced expression of PRMT6 in NRVM enhances the expression of the hypertrophic marker, atrial natriuretic peptide (ANP). Conversely, specific silencing of PRMT6 reduces ANP protein expression and cell size, indicating that PRMT6 is critical for the PE-mediated hypertrophic response. Silencing of PRMT6 reduces H3R2Me2a, a mark normally associated with transcriptional repression. Furthermore, evaluation of cardiac contractility and global ion channel activity in live NRVM shows a striking reduction of spontaneous beating rates and prolongation of extra-cellular field potentials in cells expressing low-level PRMT6. Altogether, our results indicate that PRMT6 is a critical regulator of cardiac hypertrophy, implicating H3R2Me2a as an important histone modification. This study identifies PRMT6 as a new epigenetic regulator and suggests a new point of control in chromatin to inhibit pathological cardiac remodeling., Proteins; Biochemistry; Molecular biology; Pathophysiology; Cardiology; PRMT6, Protein arginine methyltransferase 6, Histone H3 arginine methylation, Cardiac hypertrophy, Phenylephrine, Pressure overload hypertrophy, Heart failure, Epigenetics.

Mast cells are important cells of the immune system. Although, traditionally considered as key players in allergic and hypersensitivity reactions emerging evidence suggest that mast cells have many complex roles in vascular disease. These include regulation of vasodilation, angiogenesis, activation of matrix metalloproteinases, apoptosis of smooth muscle cells, and activation of the renin angiotensin system. Mast cells are also known to play an immunomodulatory role via modulation of regulatory T-cell (T-reg), macrophage and endothelial cell functions. This dual role of the mast cells is evident in myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA)-mouse model of glomerulonephritis in which mast cell deficiency worsens glomerulonephritis, whereas inhibition of mast cell degranulation is effective in abrogating the development of glomerulonephritis. Our previous work demonstrated that mast cell degranulation inhibits lipopolysaccharide (LPS)-induced interleukin 6 (IL-6) production in mice. This effect was not seen in histamine-1-receptor knockout (H1R-/-) mice suggesting a role for histamine in IL-6 homeostasis. In addition, mast cell degranulation-mediated decrease in IL-6 production was associated with an upregulation of suppressor of cytokine signaling-1 protein (SOCS-1) in the aorta. We propose that mast cells regulate large artery inflammation through T-cells, shifting a primarily Th1 and Th17 toward a Th2 response and leading to enhanced production IL-10, activation Treg cells and the inhibition of macrophage functions.

We examined the effects of two over-the-counter H1-antihistamines on the progression of fatty liver disease in male C57Bl/6 wild-type and apolipoprotein E (ApoE)−/− mice. Mice were fed a high-fat diet (HFD) for 3 mo, together with administration of either cetirizine (4 mg/kg body wt) or fexofenadine (40 mg/kg body wt) in drinking water. Antihistamine treatments increased body weight gain, gonadal fat deposition, liver weight, and hepatic steatosis in wild-type mice but not in ApoE−/− mice. Lobular inflammation, acute inflammation, and necrosis were not affected by H1-antihistamines in either genotype. Serum biomarkers of liver injury tended to increase in antihistamine-treated wild-type mice. Serum level of glucose was increased by fexofenadine, whereas lipase was increased by cetirizine. H1-antihistamines reduced the mRNA expression of ApoE and carbohydrate response element-binding protein in wild-type mice, without altering the mRNA expression of sterol regulatory element-binding protein 1c, fatty acid synthase, or ApoB100, in either genotype. Fexofenadine increased both triglycerides and cholesterol ester, whereas cetirizine increased only cholesterol ester in liver, with a concomitant decrease in serum triglycerides by both antihistamines in wild-type mice. Antihistamines increased hepatic levels of conjugated bile acids in wild-type mice, with the effect being significant in fexofenadine-treated animals. The increase was associated with changes in the expression of organic anion transport polypeptide 1b2 and bile salt export pump. These results suggest that H1-antihistamines increase the progression of fatty liver disease in wild-type mice, and there seems to be an association between the severity of disease, presence of ApoE, and increase in hepatic bile acid levels.

Summary Histamine is a well-recognized modulator of vascular inflammation. We have shown that histamine, acting via H1 receptors (H1R), synergizes lipopolysaccharide (LPS)-induced production of prostaglandin I(2) (PGI(2)), PGE(2) and interleukin-6 (IL-6) by endothelial cells. The synergy between histamine and LPS was partly attributed to histamine -induced expression of Toll-like receptor 4 (TLR4). In this study, we examined whether LPS stimulates the H1R expression in human coronary artery endothelial cells (HCAEC) with resultant enhancement of histamine responsiveness. Incubation of HCAEC with LPS (10-1000 ng/ml) resulted in two-fold to fourfold increases in H1R mRNA expression in a time-dependent and concentration-dependent fashion. In contrast, LPS treatment did not affect H2R mRNA expression. The LPS-induced H1R mRNA expression peaked by 4 hr after LPS treatment and remained elevated above the basal level for 20-24 hr. Flow cytometric and Western blot analyses revealed increased expression of H1R protein in LPS-treated cells. The specific binding of [(3)H]pyrilamine to H1R in membrane proteins from LPS-treated HCAEC was threefold higher than the untreated cells. The LPS-induced H1R expression was mediated through TLR4 as gene silencing by TLR4-siRNA and treatment with a TLR4 antagonist inhibited the LPS effect. When HCAEC were pre-treated with LPS for 24 hr, washed and challenged with histamine, 17-, 10- and 15-fold increases in PGI(2), PGE(2) and IL-6 production, respectively, were noted. Histamine-induced enhancement of the synthesis of PGI(2), PGE(2) and IL-6 by LPS-primed HCAEC was completely blocked by an H1R antagonist. The results demonstrate that LPS, through TLR4 activation, up-regulates the expression and function of H1R and amplifies histamine-induced inflammatory responses in HCAEC.

Camptothecin is one of the human success stories in the history of drug discovery from natural resources. In this mini-review, the painstaking efforts of eminent scientists of different disciplines to isolate and identify camptothecin as active anticancer compound from Camptotheca acuminata are narrated. Due course, the unique mode of action of camptothecin was discovered. Clinically some tumors acquire de novo resistance to camptothecin and a few of molecular mechanisms responsible for clinical resistance are discussed in brief. Finally, we discuss novel sources and how biotechnological methods are utilized for a sustainable production of camptothecin without impacting the natural flora.

Activation of histamine receptor 1 (H1R) reduces adiposity in mice, and chronic use of H1-antihistamines (H1-AH) increase weight gain in obese patients. Apolipoprotein E (ApoE) plays a major role in lipid transport. We examined the effects of chronic blockade of H1R by cetirizine or fexofenadine, two therapeutic H1-AH, on fatty liver disease, adiposity and weight gain in wild-type (WT) and ApoE-knockout (ApoE-/-) mice. Eight week old male WT or ApoE-/- mice were fed a high fat diet, and concurrently treated with equivalent therapeutic doses of either cetirizine or fexofenadine via drinking water for 3 months. H1-HA treatments increased weight gain, visceral adiposity, liver weight and macrovesicular hepatosteatosis in WT mice, but not in ApoE-/- mice. These changes were independent of food intake. Serum markers of liver injury tended to increase in H1-HA-treated WT mice in association with increased macrovesicular hepatosteatosis. Microvesicular hepatosteatosis and lobular inflammation were not affected b...

Mast cells are important cells of the immune system and are recognized as participants in the pathogenesis of atherosclerosis. In this study, we evaluated the role of mast cells on the progression of atherosclerosis and hepatic steatosis using the apolipoprotein E-deficient ( ApoE−/−) and ApoE−/−/mast cell-deficient ( KitW-sh/W-sh) mouse models maintained on a high-fat diet. The en face analyses of aortas showed a marked reduction in plaque coverage in ApoE−/−/KitW-sh/W-shcompared with ApoE−/−after a 6-mo regimen with no significant change noted after 3 mo. Quantification of intima/media thickness on hematoxylin and eosin-stained histological cross sections of the aortic arch revealed no significant difference between ApoE−/−and ApoE−/−/KitW-sh/W-shmice. The high-fat regimen did not induce atherosclerosis in either KitW-sh/W-shor wild-type mice. Mast cells with indications of degranulation were seen only in the aortic walls and heart of ApoE−/−mice. Compared with ApoE−/−mice, the serum levels of total cholesterol, low-density lipoprotein and high-density lipoprotein were decreased by 50% in ApoE−/−/KitW-sh/W-shmice, whereas no appreciable differences were noted in serum levels of triglycerides or very low density lipoprotein. ApoE−/−/KitW-sh/W-shmice developed significantly less hepatic steatosis than ApoE−/−mice after the 3-mo regimen. The analysis of Th1/Th2/Th17 cytokine profile in the sera revealed significant reduction of interleukin (IL)-6 and IL-10 in ApoE−/−/KitW-sh/W-shmice compared with ApoE−/−mice. The assessment of systemic generation of thromboxane A2(TXA2) and prostaglandin I2(PGI2) revealed significant decrease in the production of PGI2in ApoE−/−/KitW-sh/W-shmice with no change in TXA2. The decrease in PGI2production was found to be associated with reduced levels of cyclooxygenase-2 mRNA in the aortic tissues. A significant reduction in T-lymphocytes and macrophages was noted in the atheromas of the ApoE−/−/KitW-sh/W-shmice. These results demonstrate the direct involvement of mast cells in the progression of atherosclerosis and hepatic steatosis.

We examined the effect of intact human mast cells (HMC-1 5C6) and their selected mediators on interleukin-6 (IL-6) production and bone morphogenetic protein-2 (BMP-2) expression in human coronary artery endothelial cells (HCAEC) in the presence and absence of lipopolysaccharide (LPS). Scanning electron microscopy showed that HMC-1 5C6 cells adhere to HCAEC in cocultures. Addition of HMC-1 5C6 cells markedly enhanced the IL-6 production by quiescent and LPS-activated HCAEC even at the maximal concentration of LPS. Furthermore, mast cell-derived histamine and proteases accounted for the direct and synergistic effect of mast cells on IL-6 production that was completely blocked by the combination of histamine receptor-1 antagonist and protease inhibitors. Another novel finding is that histamine was able to induce BMP-2 expression in HCAEC. Collectively, our results suggest that endotoxin and mast cell products synergistically amplify vascular inflammation and that histamine participates in the early events of vascular calcification.

The biological effects of the anthraquinone fraction (AQf) isolated from in vitro cultures of Ophiorrhiza rugosa Wall. var decumbens (Rubiaceae) were evaluated. AQf showed differential activity on reactive oxygen species; it mediated the generation of superoxide radical and inhibited hydroxyl radical and lipid peroxidation. No considerable nitric oxide scavenging activity was observed for AQf. The AQf induced 50% cytotoxicity in Ehrlich ascites carcinoma and Dalton’s lymphoma ascites at concentrations of 130 and 60 µg/mL, respectively. It effectively reduced the inflammation induced by carrageenan in mice. An AQf concentration of 200 mg/kg body weight reduced solid tumor progression in mice. It also prolonged the life span of ascites tumor–bearing mice compared with control mice.

Around the world, the majority of people tend to adopt different health care approaches outside of the mainstream Western medicine for diseases or general well-being. These nonmainstream health care approaches are commonly referred to as complementary and alternative medicine (CAM). Although people use the words “complementary and alternative” interchangeably, they refer to two different concepts. “Complementary” confers the intention to add to conventional medicines by the use of phytomedicines, which are nonmainstream medicines. While “alternative” refers to a purely nonmainstream approach using phytomedicines, instead of a combinational medicinal treatment. The main drawback, raised by the Western medical community, is the lack of scientific evidence for the ascribed healing power of CAM, as well as the failure of large placebo controlled clinical trials to show the therapeutic efficacy of certain CAM. Nevertheless, in certain instances, the research relying on herbal products has led to the discovery of potent anticancer lead molecules such as taxol and camptothecin, and today many other candidate plant molecules are under investigation as anticancer agents. Similarly, plant activity for cardiovascular disease and other inflammatory diseases is relevant. Evidence continues to build up in support of the effects of these therapies on immunomodulation and maintenance of the physiological balance between anti- and proinflammatory mechanisms. In vitro and in vivo animal studies have shown the plausible mechanisms of CAM in preventing or curing disease to be linked to antioxidant effects, alterations in proinflammatory cell signaling, production of cytokines, and other proinflammatory mediators. To better understand and adopt these nonmainstream health approaches to complement the current standard (Western) healthcare, scientific evidence is required which is obtained via properly controlled experimentation. In this special issue we have some research papers which hold evidence of efficacy in various disease conditions. Three papers of this special issue show the effect of either hydrogen dissolved purified water or herbal natural products on atopic dermatitis (AD) like skin inflammation. The authors of one of the articles compared the effect of drinking hydrogen water (HW) or purified water (PW) on AD and showed therapeutic effect by HW over PW by effectively modulating Th1 and Th2 response. In another article, the authors induced AD like inflammation in Balb/c mice by 2, 4-dinitrofluorobenzene and studied the effect of Qingpeng ointment (QP) on alleviation of lesion severity. The authors correlated the effect of QP on AD with the inhibition of infiltration of CD4+T cells and mast cells, suppression of production of IgE and IL-4, and increase in the levels of IFN-γ. One of the papers also deals with a natural remedy for AD. The authors used a nona natural product mixture (NPM-9), which effectively suppressed Th2-mediated allergic inflammation on skin of the mouse model. Another paper attempted to study the effect Korean red ginseng (KRG) on vif gene in HIV. Patients receiving KRG and highly active antiretroviral therapy (HAART) exhibited high frequency of premature stop codons (PSC) for vif compared to patients on KRG alone or the placebo group. On the other hand, KRG induced more in-frame deletions compared to the placebo group. This study therefore suggests a therapeutic strategy for a better outcome in HIV patients by combining KRG along with HAART. Another paper demonstrates the effect of a Chinese medicine granule, Shu-Feng-Xuan-Fei (SFXF), on the gross change in the gene expression profile in T-cell-mediated immunity, during influenza virus infection. The authors studied different doses of SFXF and compared the efficacy with the control group as well as with mice which received oseltamivir. The authors concluded that SFXF restored the immune function and helped the rapid clearance of viral particles by regulating the T-cell gene expression patterns. We believe the above selected research papers, taken from those appearing in this special issue, will improve our knowledge and understanding of the immunomodulatory functions of complementary and alternative medicines.

Although increased serum histamine levels and H1R expression in the plaque are seen in atherosclerosis, it is not known whether H1R activation is a causative factor in the development of the disease, or is a host defense response to atherogenic signals. In order to elucidate how pharmacological inhibition of histamine receptor 1 (H1R) signaling affects atherogenesis, we administered either cetirizine (1 and 4 mg/kg. b.w) or fexofenadine (10 and 40 mg/kg. b.w) to ApoE−/− mice maintained on a high fat diet for three months. Mice ingesting a low dose of cetirizine or fexofenadine had significantly higher plaque coverage in the aorta and cross-sectional lesion area at the aortic root. Surprisingly, the higher doses of cetirizine or fexofenadine did not enhance atherosclerotic lesion coverage over the controls. The low dose of fexofenadine, but not cetirizine, increased serum LDL cholesterol. Interestingly, the expression of iNOS and eNOS mRNA was increased in aortas of mice on high doses of cetirizine or fexofenadine. This may be a compensatory nitric oxide (NO)-mediated vasodilatory mechanism that accounts for the lack of increase in the progression of atherosclerosis. Although the administration of cetirizine did not alter blood pressure between the groups, there was a positive correlation between blood pressure and lesion/media ratio at the aortic root in mice receiving the low dose of cetirizine. However, this association was not observed in mice treated with the high dose of cetirizine or either doses of fexofenadine. The macrophages or T lymphocytes densities were not altered by low doses of H1-antihistamines, whereas, high doses decreased the number of macrophages but not T lymphocytes. The number of mast cells was decreased only in mice treated with low dose of fexofenadine. These results demonstrate that chronic ingestion of low therapeutic doses of cetirizine or fexofenadine enhance progression of atherosclerosis.