CORM-A1 Alleviates Pro-Atherogenic Manifestations via miR-34a-5p Downregulation and an Improved Mitochondrial Function

Atherogenesis involves multiple cell types undergoing robust metabolic processes resulting in mitochondrial dysfunction, elevated reactive oxygen species (ROS), and consequent oxidative stress. Carbon monoxide (CO) has been recently explored for its anti-atherogenic potency; however, the effects of CO on ROS generation and mitochondrial dysfunction in atherosclerosis remain unexplored. Herein, we describe the anti-atherogenic efficacy of CORM-A1, a CO donor, in in vitro (ox-LDL-treated HUVEC and MDMs) and in vivo (atherogenic diet-fed SD rats) experimental models. In agreement with previous data, we observed elevated miR-34a-5p levels in all our atherogenic model systems. Administration of CO via CORM-A1 accounted for positive alterations in the expression of miR-34a-5p and transcription factors/inhibitors (P53, NF-κB, ZEB1, SNAI1, and STAT3) and DNA methylation pattern, thereby lowering its countenance in atherogenic milieu. Inhibition of miR-34a-5p expression resulted in restoration of SIRT-1 levels and of mitochondrial biogenesis. CORM-A1 supplementation further accounted for improvement in cellular and mitochondrial antioxidant capacity and subsequent reduction in ROS. Further and most importantly, CORM-A1 restored cellular energetics by improving overall cellular respiration in HUVECs, as evidenced by restored OCR and ECAR rates, whereas a shift from non-mitochondrial to mitochondrial respiration was observed in atherogenic MDMs, evidenced by unaltered glycolytic respiration and maximizing OCR. In agreement with these results, CORM-A1 treatment also accounted for elevated ATP production in both in vivo and in vitro experimental models. Cumulatively, our studies demonstrate for the first time the mechanism of CORM-A1-mediated amelioration of pro-atherogenic manifestations through inhibition of miR-34a-5p expression in the atherogenic milieu and consequential rescue of SIRT1-mediated mitochondrial biogenesis and respiration.

Pharmacological and Metabolic Significance of Bile Acids in Retinal Diseases

Bile acids (BAs) are amphipathic sterols primarily synthesized from cholesterol in the liver and released in the intestinal lumen upon food intake. BAs play important roles in micellination of dietary lipids, stimulating bile flow, promoting biliary phospholipid secretion, and regulating cholesterol synthesis and elimination. Emerging evidence, however, suggests that, aside from their conventional biological function, BAs are also important signaling molecules and therapeutic tools. In the last decade, the therapeutic applications of BAs in the treatment of ocular diseases have gained great interest. Despite the identification of BA synthesis, metabolism, and recycling in ocular tissues, much remains unknown with regards to their biological significance in the eye. Additionally, as gut microbiota directly affects the quality of circulating BAs, their analysis could derive important information on changes occurring in this microenvironment. This review aims at providing an overview of BA metabolism and biological function with a focus on their potential therapeutic and diagnostic use for retinal diseases.

Bortezomib Sustains T Cell Function by Inducing miR-155-Mediated Downregulation of SOCS1 and SHIP1

Suppressive mechanisms operating within T cells are linked to immune dysfunction in the tumor microenvironment. We have previously reported using adoptive T cell immunotherapy models that tumor-bearing mice treated with a regimen of proteasome inhibitor, bortezomib - a dipeptidyl boronate, show increased antitumor lymphocyte effector function and survival. Here, we identify a mechanism for the improved antitumor CD8⁺ T cell function following bortezomib treatment. Intravenous administration of bortezomib at a low dose (1 mg/kg body weight) in wild-type or tumor-bearing mice altered the expression of a number of miRNAs in CD8⁺ T cells. Specifically, the effect of bortezomib was prominent on miR-155 - a key cellular miRNA involved in T cell function. Importantly, bortezomib-induced upregulation of miR-155 was associated with the downregulation of its targets, the suppressor of cytokine signaling 1 (SOCS1) and inositol polyphosphate-5-phosphatase (SHIP1). Genetic and biochemical analysis confirmed a functional link between miR-155 and these targets. Moreover, activated CD8⁺ T cells treated with bortezomib exhibited a significant reduction in programmed cell death-1 (PD-1) expressing SHIP1⁺ phenotype. These data underscore a mechanism of action by which bortezomib induces miR-155-dependent downregulation of SOCS1 and SHIP1 negative regulatory proteins, leading to a suppressed PD-1-mediated T cell exhaustion. Collectively, data provide novel molecular insights into bortezomib-mediated lymphocyte-stimulatory effects that could overcome immunosuppressive actions of tumor on antitumor T cell functions. The findings support the approach that bortezomib combined with other immunotherapies would lead to improved therapeutic outcomes by overcoming T cell exhaustion in the tumor microenvironment.

Inactivation of Endothelial ADAM17 Reduces Retinal Ischemia-Reperfusion Induced Neuronal and Vascular Damage

Retinal ischemia contributes to visual impairment in ischemic retinopathies. A disintegrin and metalloproteinase ADAM17 is implicated in multiple vascular pathologies through its ability to regulate inflammatory signaling via ectodomain shedding. We investigated the role of endothelial ADAM17 in neuronal and vascular degeneration associated with retinal ischemia reperfusion (IR) injury using mice with conditional inactivation of ADAM17 in vascular endothelium. ADAM17Cre-flox and control ADAM17flox mice were subjected to 40 min of pressure-induced retinal ischemia, with the contralateral eye serving as control. Albumin extravasation and retinal leukostasis were evaluated 48 h after reperfusion. Retinal morphometric analysis was conducted 7 days after reperfusion. Degenerate capillaries were assessed by elastase digest and visual function was evaluated by optokinetic test 14 and 7 days following ischemia, respectively. Lack of ADAM17 decreased vascular leakage and reduced retinal thinning and ganglion cell loss in ADAM17Cre-flox mice. Further, ADAM17Cre-flox mice exhibited a remarkable reduction in capillary degeneration following IR. Decrease in neurovascular degeneration in ADAM17Cre-flox mice correlated with decreased activation of caspase-3 and was associated with reduction in oxidative stress and retinal leukostasis. In addition, knockdown of ADAM17 resulted in decreased cleavage of p75NTR, the process known to be associated with retinal cell apoptosis. A decline in visual acuity evidenced by decrease in spatial frequency threshold observed in ADAM17flox mice was partially restored in ADAM17-endothelial deficient mice. The obtained results provide evidence that endothelial ADAM17 is an important contributor to IR-induced neurovascular damage in the retina and suggest that interventions directed at regulating ADAM17 activity can be beneficial for alleviating the consequences of retinal ischemia.

Inhibition of HDAC6 Attenuates Diabetes-Induced Retinal Redox Imbalance and Microangiopathy

We investigated the contributing role of the histone deacetylase 6 (HDAC6) to the early stages of diabetic retinopathy (DR). Furthermore, we examined the mechanism of action of HDAC6 in human retinal endothelial cells (HuREC) exposed to glucidic stress. Streptozotocin-induced diabetic rats (STZ-rats), a rat model of type 1 diabetes, were used as model of DR. HDAC6 expression and activity were increased in human diabetic postmortem donors and STZ-rat retinas and were augmented in HuREC exposed to glucidic stress (25 mM glucose). Administration of the HDAC6 specific inhibitor Tubastatin A (TS) (10 mg/kg) prevented retinal microvascular hyperpermeability and up-regulation of inflammatory markers. Furthermore, in STZ-rats, TS decreased the levels of senescence markers and rescued the expression and activity of the histone deacetylase sirtuin 1 (SIRT1), while downregulating the levels of free radicals and of the redox stress markers 4-hydroxynonenal (4-HNE) and nitrotyrosine (NT). The antioxidant effects of TS, consequent to HDAC6 inhibition, were associated with preservation of Nrf2-dependent gene expression and up-regulation of thioredoxin-1 activity. In vitro data, obtained from HuREC, exposed to glucidic stress, largely replicated the in vivo results further confirming the antioxidant effects of HDAC6 inhibition by TS in the diabetic rat retina. In summary, our data implicate HDAC6 activation in mediating hyperglycemia-induced retinal oxidative/nitrative stress leading to retinal microangiopathy and, potentially, DR.

Ursodeoxycholic Acid Halts Pathological Neovascularization in a Mouse Model of Oxygen-Induced Retinopathy

Retinopathy of prematurity (ROP) is the leading cause of blindness in infants. We have investigated the efficacy of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine and glycine conjugated derivatives tauroursodeoxycholic acid (TUDCA) and glycoursodeoxycholic acid (GUDCA) in preventing retinal neovascularization (RNV) in an experimental model of ROP. Seven-day-old mice pups (P7) were subjected to oxygen-induced retinopathy (OIR) and were treated with bile acids for various durations. Analysis of retinal vascular growth and distribution revealed that UDCA treatment (50 mg/kg, P7-P17) of OIR mice decreased the extension of neovascular and avascular areas, whereas treatments with TUDCA and GUDCA showed no changes. UDCA also prevented reactive gliosis, preserved ganglion cell survival, and ameliorated OIR-induced blood retinal barrier dysfunction. These effects were associated with decreased levels of oxidative stress markers, inflammatory cytokines, and normalization of the VEGF-STAT3 signaling axis. Furthermore, in vitro tube formation and permeability assays confirmed UDCA inhibitory activity toward VEGF-induced pro-angiogenic and pro-permeability effects on human retinal microvascular endothelial cells. Collectively, our results suggest that UDCA could represent a new effective therapy for ROP.

Carbon monoxide releasing molecule-A1 improves nonalcoholic steatohepatitis via Nrf2 activation mediated improvement in oxidative stress and mitochondrial function

Nuclear factor-erythroid 2 related factor 2 (Nrf2)-mediated signaling plays a central role in maintaining cellular redox homeostasis of hepatic cells. Carbon monoxide releasing molecule-A1 (CORM-A1) has been reported to stimulate up-regulation and nuclear translocation of Nrf2 in hepatocytes. However, the role of CORM-A1 in improving lipid metabolism, antioxidant signaling and mitochondrial functions in nonalcoholic steatohepatitis (NASH) is unknown. In this study, we report that CORM-A1 prevents hepatic steatosis in high fat high fructose (HFHF) diet fed C57BL/6J mice, used as model of NASH. The beneficial effects of CORM-A1 in HFHF fed mice was associated with improved lipid homeostasis, Nrf2 activation, upregulation of antioxidant responsive (ARE) genes and increased ATP production. As, mitochondria are intracellular source of reactive oxygen species (ROS) and important sites of lipid metabolism, we further investigated the mechanisms of action of CORM-A1-mediated improvement in mitochondrial function in palmitic acid (PA) treated HepG2 cells. Cellular oxidative stress and cell viability were found to be improved in PA + CORM-A1 treated cells via Nrf2 translocation and activation of cytoprotective genes. Furthermore, in PA treated cells, CORM-A1 improved mitochondrial oxidative stress, membrane potential and rescued mitochondrial biogenesis thru upregulation of Drp1, TFAM, PGC-1α and NRF-1 genes. CORM-A1 treatment improved cellular status by lowering glycolytic respiration and maximizing OCR. Improvement in mitochondrial respiration and increment in ATP production in PA + CORM-A1 treated cells further corroborate our findings. In summary, our data demonstrate for the first time that CORM-A1 ameliorates tissue damage in steatotic liver via Nrf2 activation and improved mitochondrial function, thus, suggesting the anti-NASH potential of CORM-A1.

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CORM-A1 facilitates Nrf2 translocation and regulates cellular redox homeostasis in liver.

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CORM-A1 improves antioxidant status and lipid metabolism in liver.

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CORM-A1 induces mitochondrial biogenesis, improves energetics and cellular respiration in HepG2 cells.

Monosodium Urate Contributes to Retinal Inflammation and Progression of Diabetic Retinopathy

We have investigated the contributing role of monosodium urate (MSU) to the pathological processes associated with the induction of diabetic retinopathy (DR). In human postmortem retinas and vitreous from donors with DR, we have found a significant increase in MSU levels that correlated with the presence of inflammatory markers and enhanced expression of xanthine oxidase. The same elevation in MSU levels was also detected in serum and vitreous of streptozotocin-induced diabetic rats (STZ-rats) analyzed at 8 weeks of hyperglycemia. Furthermore, treatments of STZ-rats with the hypouricemic drugs allopurinol (50 mg/kg) and benzbromarone (10 mg/kg) given every other day resulted in a significant decrease of retinal and plasma levels of inflammatory cytokines and adhesion factors, a marked reduction of hyperglycemia-induced retinal leukostasis, and restoration of retinal blood-barrier function. These results were associated with effects of the hypouricemic drugs on downregulating diabetes-induced levels of oxidative stress markers as well as expression of components of the NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome such as NLRP3, Toll-like receptor 4, and interleukin-1β. The outcomes of these studies support a contributing role of MSU in diabetes-induced retinal inflammation and suggest that asymptomatic hyperuricemia should be considered as a risk factor for DR induction and progression.

Bortezomib impacts Notch—miR-155 mediated augmentation of CD8+T Cell antitumor immunity

The immunosuppressive tumor microenvironment dampens host antitumor immunity by multiple mechanisms including interference with the Notch system, which is important for various cell fate decisions and hematopoietic cell differentiation and function. We observed that treatment with bortezomib, a proteasome inhibitor, in mice bearing subcutaneous tumors resulted in an upregulated expression of various Notch signaling components in lymphoid tissues and increased CD8+T lymphocyte IFNγ secretion and expression of effector molecules, perforin and granzyme-B, as well as the T-box transcription factor eomesodermin. Of note, bortezomib reversed tumor-induced downregulation of Notch receptors, Notch1 and Notch2, as well as increased the levels of cleaved Notch intracellular domain (NICD) and downstream targets Hes1 and Hey1 in tumor-draining CD8+T cells. These data suggest that bortezomib can reverse tumor-induced dysfunction of CD8+T cells by its intrinsic stimulatory effects. Our preliminary data also suggest that bortezomib can positively regulate miR-155 expression in CD8+ T cells from mice bearing tumor. Further, miR-155 suppression was found to downregulate bortezomib-induced increase in Notch target genes in T cells. We are currently elucidating how bortezomib affects the expression of miR-155 and its target genes, such as suppressor of cytokine signaling 1 (SOCS1) and inositol polyphosphate-5-phosphatase (SHIP1) that are associated with T cell function. These data provide novel insights on using bortezomib not only as an agent to sensitize tumors to cell death, but also to provide lymphocyte-stimulatory effects, thereby overcoming immunosuppressive actions of tumor on antitumor T cell functions.

Deoxycholylglycine, a conjugated secondary bile acid, reduces vascular tone by attenuating Ca2+ sensitivity via rho kinase pathway

Patients with cirrhosis have reduced systemic vascular resistance and elevated circulating bile acids (BAs). Previously, we showed that secondary conjugated BAs impair vascular tone by reducing vascular smooth muscle cell (VSMC) Ca²⁺ influx. In this study, we investigated the effect of deoxycholylglycine (DCG), on Ca²⁺ sensitivity in reducing vascular tone. First, we evaluated the effects of DCG on U46619- and phorbol-myristate-acetate (PMA)-induced vasoconstriction. DCG reduced U46619-induced vascular tone but failed to reduce PMA-induced vasoconstriction. Then, by utilizing varied combinations of diltiazem (voltage-dependent Ca²⁺ channel [VDCC] inhibitor), Y27632 (RhoA kinase [ROCK] inhibitor) and chelerythrine (PKC inhibitor) for the effect of DCG on U46619-induced vasoconstriction, we ascertained that DCG inhibits VDCC and ROCK pathway with no effect on PKC. We further assessed the effect of DCG on ROCK pathway. In β-escin-permeabilized arteries, DCG reduced high-dose Ca²⁺- and GTPγS (a ROCK activator)-induced vasoconstriction. In rat vascular smooth muscle cells (VSMCs), DCG reduced U46619-induced phosphorylation of myosin light chain subunit (MLC₂₀) and myosin phosphatase target subunit-1 (MYPT1). In permeabilized VSMCs, DCG reduced Ca²⁺- and GTPγS-mediated MLC₂₀ and MYPT1 phosphorylation, and further, reduced GTPγS-mediated membrane translocation of RhoA. In VSMCs, long-term treatment with DCG had no effect on ROCK2 and RhoA expression. In conclusion, DCG attenuates vascular Ca²⁺ sensitivity and tone via inhibiting ROCK pathway. These results enhance our understanding of BAs-mediated regulation of vascular tone and provide a platform to develop new treatment strategies to reduce arterial dysfunction in cirrhosis.

Abstract 647: Bortezomib enhances CD8+ T Lymphocyte antitumor effector function: Potential mechanism(s) via notch regulation

The immunosuppressive tumor microenvironment disturbs host antitumor immunity by multiple mechanisms including interference with the Notch system, which is important for various metazoan cell fate decisions and hematopoietic cell differentiation and function. We observed that treatment with the proteasome inhibitor bortezomib in mice bearing various solid tumors resulted in an upregulated expression of various Notch signaling components in lymphoid tissues, thereby increasing CD8+ T lymphocyte IFNγ secretion and expression of effector molecules, perforin and granzyme B, as well as the T-box transcription factor eomesodermin. Of note, bortezomib reversed tumor-induced downregulation of Notch receptors, Notch1 and Notch2, as well as increased the levels of cleaved Notch intracellular domain (NICD) and downstream targets Hes1 and Hey1 in tumor-draining CD8+ T cells. Moreover, bortezomib promoted CD8+ T cell nuclear factor-κB (NFκB) activity by increasing the total and phosphorylated levels of the IκB kinase and IκBα as well as the cytoplasmic and nuclear levels of phosphorylated p65. Even when we blocked NFκB activity by Bay-11-7082, or NICD cleavage by γ-secretase inhibitor, bortezomib significantly increased expression of Notch Hes1 and Hey1 genes as well as perforin, granzyme B and eomesodermin in activated CD8+ T cells. Data suggest that bortezomib can rescue tumor-induced dysfunction of CD8+ T cells by its intrinsic stimulatory effects promoting NICD-NFκB crosstalk. We are also elucidating components of microRNA regulation affecting NICD-NFκB crosstalk. Our preliminary data suggest that bortezomib is also able to positively regulate miR-155 expression in CD8+ T cells from mice bearing tumor. As well as, miR-155 suppression downregulates bortezomib-induced increase in Notch target genes in T cells. We are currently investigating alternative proteasome inhibitors in order to understand whether bortezomib’s effect on miR-155 expression in CD8+ T cells is specific to bortezomib or primarily conducive to a proteasome inhibition effect. These findings provide novel insights on using bortezomib not only as an agent to sensitize tumors to cell death, but also to provide lymphocyte-stimulatory effects, thereby overcoming immunosuppressive actions of tumor on antitumor T cell functions.

Citation Format: Ariana N. Renrick, Menaka C. Thounaojam, Portia Thomas, Samuel T. Pellom, Anil Shanker. Bortezomib enhances CD8+ T Lymphocyte antitumor effector function: Potential mechanism(s) via notch regulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 647. doi:10.1158/1538-7445.AM2017-647

Bortezomib augments lymphocyte stimulatory cytokine signaling in the tumor microenvironment to sustain CD8+T cell antitumor function

Tumor-induced immune tolerance poses a major challenge for therapeutic interventions aimed to manage cancer. We explored approaches to overcome T-cell suppression in murine breast and kidney adenocarcinomas, and lung fibrosarcoma expressing immunogenic antigens. We observed that treatment with a reversible proteasome inhibitor bortezomib (1 mg/kg body weight) in tumor-bearing mice significantly enhanced the expression of lymphocyte-stimulatory cytokines IL-2, IL-12, and IL-15. Notably, bortezomib administration reduced pulmonary nodules of mammary adenocarcinoma 4T1.2 expressing hemagglutinin (HA) model antigen (4T1HA) in mice. Neutralization of IL-12 and IL-15 cytokines with a regimen of blocking antibodies pre- and post-adoptive transfer of low-avidity HA518-526-specific CD8+T-cells following intravenous injection of 4T1HA cells increased the number of pulmonary tumor nodules. This neutralization effect was counteracted by the tumor metastasis-suppressing action of bortezomib treatments. In bortezomib-treated 4T1HA tumor-bearing mice, CD4+T-cells showed increased IL-2 production, CD11c+ dendritic cells showed increased IL-12 and IL-15 production, and HA-specific activated CD8+T-cells showed enhanced expression of IFNγ, granzyme-B and transcription factor eomesodermin. We also noted a trend of increased expression of IL-2, IL-12 and IL-15 receptors as well as increased phosphorylation of STAT5 in tumor-infiltrating CD8+T-cells following bortezomib treatment. Furthermore, bortezomib-treated CD8+T-cells showed increased phosphorylation of mitogen-activated protein kinase p38, and Akt, which was abrogated by phosphatidylinositide 3-kinase (PI3K) inhibitor. These data support the therapeutic potential of bortezomib in conjunction with other immunotherapies to augment the strength of convergent signals from CD8+T-cell signaling molecules including TCR, cytokine receptors and downstream PI3K/Akt/STAT5 pathways to sustain CD8+T-cell effector function in the tumor microenvironment.

Abstract 4161: Bortezomib enhances expression of effector molecules in antitumor CD8+ T lymphocytes by modulating Notch-NF-kB-miR-155 crosstalk

The immunosuppressive tumor microenvironment usurps host antitumor immunity by multiple mechanisms including interference with the Notch system, which is important for various metazoan cell fate decisions and hematopoietic cell differentiation and function. We observed that treatment with the proteasome inhibitor bortezomib in mice bearing various solid tumors resulted in an upregulated expression of various Notch signaling components in lymphoid tissues, thereby increasing CD8+T-lymphocyte IFNγ secretion and expression of effector molecules, perforin and granzyme B, as well as the T-box transcription factor eomesodermin. Bortezomib also neutralized TGFβ-mediated suppression of IFNγ and granzyme B expression in activated CD8+T-cells. Of note, bortezomib reversed tumor-induced downregulation of Notch receptors, Notch1 and Notch2, as well as increased the levels of cleaved Notch intracellular domain (NICD) and downstream targets Hes1 and Hey1 in tumor-draining CD8+T-cells. Moreover, bortezomib promoted CD8+T-cell nuclear factor-κB (NF-κB) activity by increasing the total and phosphorylated levels of the IκB kinase and IκBα as well as the cytoplasmic and nuclear levels of phosphorylated p65. Even when we blocked NFκB activity by Bay-11-7082, or NICD cleavage by γ-secretase inhibitor, bortezomib significantly increased expression of Notch Hes1 and Hey1 genes as well as perforin, granzyme B and eomesodermin in activated CD8+T-cells. Data suggest that bortezomib can rescue tumor-induced dysfunction of CD8+T-cells by its intrinsic stimulatory effects promoting NICD-NFκB crosstalk. We are also elucidating components of microRNA regulation affecting NICD-NFκB crosstalk. Our preliminary data suggest that miR-155 plays a role in bortezomib-induced regulation of T cell function. These findings provide novel insights on using bortezomib not only as an agent to sensitize tumors to cell death, but also to provide lymphocyte-stimulatory effects, thereby overcoming immunosuppressive actions of tumor on anti-tumor T-cell functions.

Citation Format: Ariana N. Renrick, Menaka C. Thounaojam, Duafalia F. Dudimah, Portia Thomas, Samuel T. Pellom, Roman V. Uzhachenko, Anil Shanker. Bortezomib enhances expression of effector molecules in antitumor CD8+ T lymphocytes by modulating Notch-NF-kB-miR-155 crosstalk. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4161.

Bortezomib Improves Adoptive T-cell Therapy by Sensitizing Cancer Cells to FasL Cytotoxicity

Cancer immunotherapy shows great promise but many patients fail to show objective responses, including in cancers that can respond well, such as melanoma and renal adenocarcinoma. The proteasome inhibitor bortezomib sensitizes solid tumors to apoptosis in response to TNF-family death ligands. Because T cells provide multiple death ligands at the tumor site, we investigated the effects of bortezomib on T-cell responses in immunotherapy models involving low-avidity antigens. Bortezomib did not affect lymphocyte or tissue-resident CD11c(+)CD8(+) dendritic cell counts in tumor-bearing mice, did not inhibit dendritic cell expression of costimulatory molecules, and did not decrease MHC class I/II-associated antigen presentation to cognate T cells. Rather, bortezomib activated NF-κB p65 in CD8(+) T cells, stabilizing expression of T-cell receptor CD3ζ and IL2 receptor-α, while maintaining IFNγ secretion to improve FasL-mediated tumor lysis. Notably, bortezomib increased tumor cell surface expression of Fas in mice as well as human melanoma tissue from a responsive patient. In renal tumor-bearing immunodeficient Rag2(-/-) mice, bortezomib treatment after adoptive T-cell immunotherapy reduced lung metastases and enhanced host survival. Our findings highlight the potential of proteasome inhibitors to enhance antitumor T-cell function in the context of cancer immunotherapy.

Bortezomib enhances expression of effector molecules in anti-tumor CD8+ T lymphocytes by promoting Notch-nuclear factor-κB crosstalk

The immunosuppressive tumor microenvironment usurps host antitumor immunity by multiple mechanisms including interference with the Notch system, which is important for various metazoan cell fate decisions and hematopoietic cell differentiation and function. We observed that treatment with the proteasome inhibitor bortezomib in mice bearing various solid tumors resulted in an upregulated expression of various Notch signaling components in lymphoid tissues, thereby increasing CD8+T-lymphocyte IFNγ secretion and expression of effector molecules, perforin and granzyme B, as well as the T-box transcription factor eomesodermin. Bortezomib also neutralized TGFβ-mediated suppression of IFNγ and granzyme B expression in activated CD8+T-cells. Of note, bortezomib reversed tumor-induced downregulation of Notch receptors, Notch1 and Notch2, as well as increased the levels of cleaved Notch intracellular domain (NICD) and downstream targets Hes1 and Hey1 in tumor-draining CD8+T-cells. Moreover, bortezomib promoted CD8+T-cell nuclear factor-κB (NFκB) activity by increasing the total and phosphorylated levels of the IκB kinase and IκBα as well as the cytoplasmic and nuclear levels of phosphorylated p65. Even when we blocked NFκB activity by Bay-11-7082, or NICD cleavage by γ-secretase inhibitor, bortezomib significantly increased expression of Notch Hes1 and Hey1 genes as well as perforin, granzyme B and eomesodermin in activated CD8+T-cells. Data suggest that bortezomib can rescue tumor-induced dysfunction of CD8+T-cells by its intrinsic stimulatory effects promoting NICD-NFκB crosstalk. These findings provide novel insights on using bortezomib not only as an agent to sensitize tumors to cell death but also to provide lymphocyte-stimulatory effects, thereby overcoming immunosuppressive actions of tumor on anti-tumor T-cell functions.

Abstract 4059: Crosstalk between CD8+ T and NK cells: fine-tuning of antitumor immune response

Local tumor antigen-specific T cell-NK cell collaboration is indispensable for the elimination of tumor cells, including antigen-deficient tumor escape variants before metastasis. While mechanistic details are available for the innate instruction of the T cell responses, little is known for the adaptive control of NK cell activity. We observed in a mouse model of mastocytoma expressing a self tumor antigen P1A that effector CD8+ T cells provided a necessary “help” to dormant NK cells in eliciting their antitumor effector function. Bioluminescence imaging of mastocytoma tumors following adoptive transfer of P1A-specific T cells in RAG-/- and RAG-/-γc-/- mice showed that NK cell anti-tumor activity requires cytolytic T cells, whereas T cells can function independent of NK cells. In 2D and 3D co-culture systems, we observed that PMA/ionomycin-stimulated CD8+ T cells form multiple contacts with naïve NK lymphocytes. Data show that NK cells interacting with activated CD8+ T cells show an up-regulation of CD25 and CD69 expression mediated by intercellular contacts, and activation of NKG2D receptors and Stat2, Stat6, Jak1, Jak3, Tyk2, and PTEN signaling molecules with a decrease in the phosphorylation of Stat1, PKB/Akt, SAPK/JNK, p38. On the other hand, interacting NK cells down-regulate CD25 molecule expression on CD8+ T cells and promote differentiation of central memory CD44+CD62L+ T cells. CD8+ T cells display an elevation in the phosphorylation of Stat1 and down-regulation of Stat5 with stimulated PKB/Akt, Lck, mTOR, and p42/p44. Moreover, significant changes in the cytosolic and mitochondrial Ca2+, production of mitochondrial ROS, mitochondrial membrane potential, mitochondrial permeability transition pore, and synthesis of nitric oxide and non-protein thiols (mostly, reduced glutathion) were observed in a reciprocal T cell-NK cell interaction. These results highlight the importance of mitochondrial activity in the re-modeling of activation signaling and memory differentiation of interacting CD8 T cells and NK cells. These results will help refine cancer immunotherapeutic strategies.

Citation Format: Roman V. Uzhachenko, J Shawn Goodwin, Lino Costa, Alexander Terekhov, Menaka C. Thounaojam, William H. Hofmeister, Anil Shanker. Crosstalk between CD8+ T and NK cells: fine-tuning of antitumor immune response. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4059. doi:10.1158/1538-7445.AM2015-4059

MicroRNAs in the brain: it's regulatory role in neuroinflammation

MicroRNAs (miRNAs) are single-stranded noncoding regions of approximately 21 nucleotides that regulate protein synthesis by targeting mRNAs for translational repression or degradation at the post-transcriptional level. These classes of RNAs are highly conserved across species and are known to regulate several protein-coding genes in humans. Therefore, their dysregulation is synonymous with inflammation, autoimmunity, neurodegeneration, viral infections, heart diseases, and cancer, among other conditions. Recent years have witnessed considerable amount of research interest in studies on miRNA-mediated modulation of gene function during neuroinflammation. This review is a meticulous compilation of information on biogenesis of miRNAs and their role in neuroinflammatory diseases. Further, their potential as markers of inflammatory diseases or novel therapeutic agents against neuroinflammation has also been discussed in detail.

Hepatoprotective potential of Tecomella undulata stem bark is partially due to the presence of betulinic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Tecomella undulata (TU;` Family Bignoniaceae) is used in Indian Ayurvedic system of medicine for treating various diseases including hepatic ailments. It is also incorporated in various marketed hepatoprotective polyherbal formulations.

AIM

The present study was aimed at evaluating possible hepatoprotective role of isolated compounds from TU stem bark (TSB) using in vitro and in vivo experimental models.

METHODS

In vitro cytotoxicity and hepatoprotective potential of various extract, fractions and isolated compounds from TU stem bark were evaluated using HepG2 cells. Rats were pre-treated with TU methanolic extract (TSB-7) or betulinic acid (MS-2) or silymarin for 7 days followed by a single dose of CCl(4) (0.5 ml/kg, i.p.). Plasma markers of hepatic damage, hepatic antioxidants and indices of lipid peroxidation along with microscopic evaluation of liver were assessed in control and treatment groups.

RESULTS

TSB-2 and MS-1 accounted for significant cell death whereas; TSB-1, TBS-7, TSB-9, TSB-10 and, MS-2 did not register significant cytotoxicity. Further, non-cytotoxic components exhibited ascending grade of hepatoprotection in vitro (TSB-10<TSB-1<TSB-7<TSB-9<MS-2). Pre-treatment of TSB-7 or MS-2 to CCl(4) treated rats prevented hepatocyte damage as evidenced by biochemical and histopathological observations.

CONCLUSION

It can be concluded that, hepatoprotective potential of Tecomella undulata stem bark is partially due to the presence of betulinic acid.

Anthocyanin-rich red cabbage (Brassica oleracea L.) extract attenuates cardiac and hepatic oxidative stress in rats fed an atherogenic diet

BACKGROUND

Oxidative stress induced by reactive oxygen species plays an important role in the aetiology of several diseases including atherosclerosis and coronary heart disease. Anthocyanin-rich extracts have been shown to possess a variety of therapeutic roles, including antioxidant, cardioprotective and hepatoprotective properties. The present inventory was undertaken to evaluate the protective role of anthocyanin-rich red cabbage extract (ARCE) on an atherogenic (ATH) diet-induced hypercholesterolaemia and related cardiac and, hepatic oxidative stress in rats.

RESULTS

ARCE (100 mg kg(-1) body weight) treatment of rats fed the ATH diet significantly prevented elevation in serum and tissue lipids, circulating levels of cardiac and hepatic damage markers, and resulted in excretion of lipids through faeces. Also, the ARCE extract significantly attenuated alterations in the cardiac and hepatic antioxidants and lipid peroxidation, and histopathological changes in cardiac and hepatic tissue.

CONCLUSION

Thus, the present study provides the first scientific evidence for a protective role of ARCE against ATH diet-induced hypercholesterolaemia and cardiac and hepatic oxidative stress.

Amelioration of carbon tetrachloride induced hepatotoxicity in rats by standardized Feronia limonia. Linn leaf extracts

The hepatoprotective potential of standardized Feronia limonia (Family, Rutaceae) methanolic extract (FL-7) and chloroform soluble fraction (FL-9) were assessed against carbon tetrachloride (CCl4) induced oxidative stress and hepatotoxicity in rats. Rats treated with CCl4 recorded significant elevation in plasma markers of hepatic injury, alteration in hepatic antioxidant status and histopathological damages. However, rats pretreated with FL-7 (200 or 400 mg/kg, p.o.) and FL-9 (100 or 200 mg/kg, p.o.) for 7 days and later administered CCl4 (0.5 ml/kg, i.p.) recorded lowered indices of the above mentioned parameters and minimal histological damage in a dose dependent manner. These results were comparable to that of CCl4+silymarin treated rats. The results obtained with FL-7 and FL-9 are attributable to their free radical scavenging potential due to high contents of polyphenols and flavonols recorded herein. Overall, this study establishes the efficacy of FL-7 and FL-9 as hepatoprotective agents against CCl4 induced hepatotoxicity in rats.

Sida rhomboidea.Roxb aqueous extract down-regulates in vivo expression of vascular cell adhesion molecules in atherogenic rats and inhibits in vitro macrophage differentiation and foam cell formation

The present study evaluates efficacy of Sida rhomboidea.Roxb (SR) leaves extract in ameliorating experimental atherosclerosis using in vitro and in vivo experimental models. Atherogenic (ATH) diet fed rats recorded significant increment in the serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), very LDL (VLDL), autoantibody against oxidized LDL (Ox-LDL), markers of LDL oxidation and decrement in high-density lipoprotein (HDL) along with increment in aortic TC and TG. The ex vivo LDL oxidation assay revealed an increased susceptibility of LDL isolated from ATH rats to undergo copper mediated oxidation. These set of changes were minimized by simultaneous co-supplementation of SR extract to ATH diet fed rats. Histopathology of aorta and immunolocalization studies recorded pronounced atheromatous plaque formation, vascular calcification, significant elastin derangements and higher expression of macrophage surface marker (F4/80), vascular cell adhesion molecule-1 (VCAM-1) and p-selectin in ATH rats. Whereas, ATH+SR rats depicted minimal evidence of atheromatous plaque formation, calcium deposition, distortion/defragmentation of elastin and accumulation of macrophages along with lowered expression of VCAM-1 and P-selectin compared to ATH rats. Further, monocyte to macrophage differentiation and in vitro foam cell formation were significantly attenuated in presence of SR extract. In conclusion, SR extract has the potency of controlling experimental atherosclerosis and can be used as promising herbal supplement in combating atherosclerosis.

Hepatoprotective activity of Feronia limonia root

OBJECTIVES

The aim of this study was to evaluate the hepatoprotective potential of a methanolic extract and of marmesin isolated from the root bark of Feronia limonia.

METHODS

Activity levels of aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT), cell viability and cell death were evaluated in HepG2 cells (human liver hepatoma cells) treated with CCl₄ in the presence or absence of F. limonia extract or marmesin. Plasma activity levels of AST, ALT, bilirubin, alkaline phosphatase, protein, hepatic antioxidants, lipid peroxidation and histopathological evaluations were carried out in rats treated with CCl₄ alone or co-supplemented with F. limonia extract or marmesin in a dose-dependent manner.

KEY FINDINGS

In-vitro co-supplementation of F. limonia methanolic extract or marmesin significantly minimized alteration in levels of AST and ALT and improved cell viability. Oral administration of F. limonia methanolic extract or marmesin significantly prevented CCl₄-induced elevation in the plasma markers of hepatic damage and hepatic lipid peroxidation and a decrease in hepatic antioxidants. In-vivo hepatoprotective potential of F. limonia methanolic extract and marmesin was evident from the minimal alterations in the histoarchitecture of liver.

CONCLUSIONS

This has been the first scientific report on the hepatoprotective potential of F. limonia root bark methanolic extract and marmesin.

Traditional uses, phytochemistry and pharmacology of Clerodendron glandulosum Coleb--a review

Present review for the first time provides a complete botanical description and information on ethnomedicinal uses of Clerodendron glandulosum.Coleb (CG; Fam, Verbenaceae). Recent studies conducted from our laboratory provide pharmacological evidence for its anti-hypertensive, anti-diabetic and anti-obesity potentials. Further, its beneficial potential in preventing in vitro and in vivo non-alcoholic steatohepatitis and atherosclerosis and potent hepatoprotective and free radical scavenging abilities along with its acute and sub-chronic toxicological evaluations are also reported from our laboratory. In keeping with its traditional uses, CG extract was capable of ameliorating experimentally induced hypertension, diabetes and obesity. Its beneficial potential against NASH induced oxidative stress and atherosclerosis can be attributed to its potent free radical scavenging potential. Non-toxic nature of CG leaf extract further provides added merit to its reported pharmacological properties. The present review summarizes the pioneering scientific evidence for the pharmacological effects of CG against related metabolic disorders like hypertension, diabetes and obesity along with anti oxidant potential and beneficial effects against non alcoholic steatohepatitis.

Clerodendron glandulosum.Coleb leaf extract attenuates in vitro macrophage differentiation and expression of VCAM-1 and P-selectin in thoracic aorta of atherogenic diet fed rats

Present inventory evaluates the anti-atherogenic potential of C. glandulosum.Coleb leaf extract (CG) using in vivo and in vitro experimental models. Serum markers of low density lipoprotein (LDL-C) oxidation, cholesterol, triglycerides, lipoproteins, auto-antibody titer, ex vivo LDL-C oxidation, LDL-C aggregation, aortic lipids, histopathological evaluations and immunolocalization of macrophage surface marker (F4/80), vascular cell adhesion molecule-1 (VCAM-1) and P-selectin were performed in CON [rats treated with single dose of saline (i.p.) and fed with laboratory chow], ATH [rats treated with single dose of vitamin D3 (600,000 IU, i.p) and fed with atherogenic diet] and ATH+CG [rats treated with single dose of vitamin D3 (600,000 IU, i.p.) and fed with atherogenic diet and simultaneously treated with 200 mg/kg CG extract, p.o.] for 8 weeks. CG extract supplementation to atherogenic diet fed rats significantly prevented increment in serum cholesterol, triglycerides, and lipoproteins, markers of LDL-C oxidation, auto-antibody titer and aortic lipids. Also, LDL-C isolated from ATH+CG rats recorded mimimal aggregation and susceptibility to undergo ex vivo LDL-C oxidation. Microscopic evaluation of thoracic aorta of ATH+CG rats reveled prevention of atheromatous plaque formation, accumulation of lipid laden macrophages, calcium deposition, distortion/defragmentation of elastin, accumulation of macrophages and, down regulation of cell adhesion molecules (VCAM-1 and P-selectin) expression. Further, in vitro monocyte to macrophage differentiation was significantly attenuated in presence of CG extract (200 µg/mL). It can be concluded from the present study that, CG extract is capable of controlling induction of experimental atherosclerosis and warrants further scrutiny at the clinical level as a possible therapeutic agent.

Oxidative stress induced apoptosis of human lung carcinoma (A549) cells by a novel copper nanorod formulation

This study elucidates the process of synthesis of copper (Cu) nanorods using almond skin extract as stabilizing cum capping agent. These nanorods were (about 200 nm long and 40 nm wide) characterized by transmission electron microscopy (TEM). Further, cytotoxicity potential of these nanorods was evaluated in A549 cells (Human lung carcinoma cell line) via cell viability assay and extracellular lactate dehydrogenase (LDH) release. Also, reduced glutathione (GSH), lipid peroxidation (LPO), cellular oxidative stress (Rhodamine 123 florescence) and apoptosis (Annexin V FITC/Propidium iodide staining) were also investigated in control and treated cells. Results indicated that Cu nanorods induced apoptotic death of cancer cells by induction of oxidative stress, depletion of cellular antioxidants and mitochondrial dysfunction. This study reports a novel process of synthesis of almond skin extract capped Cu nanorods and its potential as an anticancer agent against A549 lung carcinoma cells.

Sida rhomboidea. Roxb leaf extract down-regulates expression of PPARγ2 and leptin genes in high fat diet fed C57BL/6J Mice and retards in vitro 3T3L1 pre-adipocyte differentiation

Sida rhomboidea. Roxb leaf extract (SRLE) is being used by the populace of North-East India to alleviate symptoms of diabetes and obesity. We have previously reported its hypolipidemic and anti-diabetic properties. In this study, we report the effect of SRLE on (i) in vivo modulation of genes controlling high fat diet (HFD) induced obesity and (ii) in vitro 3T3L1 pre-adipocyte differentiation and leptin release. Supplementation with SRLE significantly prevented HFD induced increment in bodyweight, plasma lipids and leptin, visceral adiposity and adipocyte hypertrophy. Also, SRLE supplementation reduced food intake, down regulated PPARγ2, SREBP1c, FAS and LEP expressions and up-regulated CPT-1 in epididymal adipose tissue compared to obese mice. In vitro adipogenesis of 3T3L1 pre-adipocytes was significantly retarded in the presence of SRLE extract. Also decreased triglyceride accumulation, leptin release and glyceraldehyde-3-Phosphate dehydrogenase activity along with higher glycerol release without significant alteration of viability of 3T3L1 pre-adipocytes, was recorded. Our findings suggest that prevention of HFD induced visceral adiposity is primarily by down regulation of PPARγ2 and leptin gene expression coupled with attenuation of food intake in C57BL/6J mice. SRLE induced prevention of pre-adipocytes differentiation, and leptin release further substantiated these findings and scientifically validates the potential application of SRLE as a therapeutic agent against obesity.

Anti-obesity potential of Clerodendron glandulosum.Coleb leaf aqueous extract

ETHNOPHARMACOLOGICAL RELEVANCE

Clerodendron glandulosum.Coleb leaf aqueous extract (CG) is traditionally used by people of North-East India to alleviate symptoms of diabetes, obesity and hypertension. Previous study from our laboratory have documented anti-diabetic and anti-hypertensive properties of CG extract but, till date there are no pharmacological studies available on its anti-obesity potential. This inventory investigates the underlining molecular mechanism/s of CG induced regulation of in vivo HFD induced obesity and in vitro adipocyte differentiation.

AIM

To evaluate effects of CG extract on (i) expression of genes regulating visceral adiposity and (ii) in vitro adipocyte differentiation and LEP release.

MATERIALS AND METHODS

Body weight, lee index, plasma lipids and LEP, mRNA expression of PPARγ-2, SREBP1c, FAS, CPT-1 and LEP in epididymal adipose tissue of control and experimental groups were evaluated. Also, potential of CG extract on in vitro adipocyte differentiation and LEP release was assessed.

RESULTS

Supplementation of CG extract to HFD fed mice significantly prevented HFD induced increment in bodyweight, lee index, plasma lipids and LEP, visceral adiposity and adipocyte hypertrophy. Also, CG extract supplementation resulted in down regulation of PPARγ-2, SREBP1c, FAS and LEP expression along with up-regulation of CPT-1 in epididymal adipose tissue compared to HFD fed mice. In vitro study recorded significant anti-adipogenic effect of CG extract that resulted in decreased adipogenesis, TG accumulation, LEP release, G3PDH activity along with higher glycerol release without significantly altering viability of 3T3L1 pre-adipocytes.

CONCLUSIONS

Clerodendron glandulosum.Coleb extract prevents adipocyte differentiation and visceral adiposity by down regulation of PPARγ-2 related genes and Lep expression thus validating its traditional therapeutic use in controlling obesity.

Protective effect of Clerodendron glandulosum extract against experimentally induced metabolic syndrome in rats

CONTEXT

Metabolic syndrome (MetS) has become one of the major health burdens worldwide. To date, no single pharmacological agent has been developed to correct metabolic abnormalities associated with MetS. Use of indigenous medicinal plants as alternative medicines against MetS could be beneficial due to multiple therapeutic usage, easy availability, and relatively few side effects.

OBJECTIVE

To investigate the protective effect of Clerodendron glandulosum Coleb. (Verbenaceae) aqueous leaf extract (CgE) against experimentally induced MetS in rats.

METHODS

Changes in body weight, food and fluid intake, plasma glucose, insulin, fasting insulin resistance index (FIRI), plasma total lipid profile, free fatty acids (FFA), oral glucose tolerance test (OGTT), blood pressure and vascular reactivity have been investigated in various experimental groups.

RESULTS

Fructose+CgE groups recorded significant decrement (P <0.05) in plasma glucose, insulin, FIRI, total cholesterol, triglycerides, LDL, VLDL and FFA, whereas plasma HDL level was significantly increased (P <0.05) along with an efficient clearance of glucose during OGTT and lowered area under curve values. FRU+CgE groups also showed significantly decreased (P <0.05) mean arterial blood pressure along with decreased vasoconstriction and increased vasorelaxation in response to administration of various pharmacological agents. These results were comparable with metformin treated rats.

DISCUSSION

C. glandulosum leaf extract ameliorates experimentally induced MetS by improving dyslipidemia and insulin resistance.

CONCLUSION

This study provides the first pharmacological evidence for the protective role of C. glandulosum leaves against experimentally induced MetS. Thus, therapeutic use of C. glandulosum in controlling MetS is indicated.

Sida rhomboidea.Roxb leaf extract ameliorates gentamicin induced nephrotoxicity and renal dysfunction in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Sida rhomboidea.Roxb (SR) known as "Mahabala" in Ayurveda and marketed as "Shahadeyi" is used in ethnomedicine to treat ailments such as dysuria and urinary disorders.

AIM OF THE STUDY

To evaluate nephroprotective potential of SR against gentamicin (GM) induced nephrotoxicity and renal dysfunction.

MATERIALS AND METHODS

Nephrotoxicity was induced in rats with GM (100 mg/kg bodyweight (i.p.) for 8 days) and were treated with SR extract (200 and 400 mg/kg bodyweight (p.o.) for 8 days) or 0.5% carboxymethyl cellulose (vehicle). Plasma and urine urea and creatinine, renal enzymatic and non-enzymatic antioxidants along with lipid peroxidation were evaluated in various experimental groups.

RESULTS

GM treatment induced significant elevation (p<0.05) in plasma and urine urea, creatinine, renal lipid peroxidation along with significant decrement (p<0.05) in renal enzymatic and non-enzymatic antioxidants. SR treatment to GM treated rats (GM+SR) recorded significant decrement (p<0.05) in plasma and urine urea and creatinine, renal lipid peroxidation along with significant increment (p<0.05) in renal enzymatic and non-enzymatic antioxidants.

CONCLUSION

SR leaf extract ameliorates GM induced nephrotoxicity and renal dysfunction and thus validates its ethnomedicinal use.

Toxicological evaluation and hepatoprotective potential of Clerodendron glandulosum.Coleb leaf extract

This inventory evaluates toxicological effects and hepatoprotective potential of Clerodendron glandulosum.Coleb (CG) aqueous extract. Acute and subchronic toxicity tests were performed using Swiss albino mice as per the guideline of Organisation for Economic Cooperation and Development (OECD). Also, hepatoprotective potential of CG extract was examined in experimental model of carbon tetrachloride (CCl 4)-induced hepatotoxicity. Acute and subchronic toxicity tests revealed that CG extract is non-toxic and its median lethal dose (LD50) value is >5000 mg/kg bodyweight. Also, rats pretreated with CG extract followed by administration of CCl4 recorded significant decrement in plasma marker enzymes of hepatic damage, total bilirubin content and hepatic lipid peroxidation. While, hepatic reduced glutathione, ascorbic acid content, activity levels of superoxide and catalase and plasma total protein content were significantly increased. Microscopic examination of liver showed that pretreatment with CG extract prevented CCl4-induced hepatic damage in CG + CCl 4 group. CG extract has hepatoprotective potential by modulating activity levels of enzymes and metabolites governing liver function and by helping in maintaining cellular integrity of hepatocytes that is comparable with that of standard drug silymarin. CG extract exhibits potent hepatoprotective activity against CCl4-induced hepatic damage but does not exhibit any toxic manifestations.

Cardioprotective effect of Sida rhomboidea. Roxb extract against isoproterenol induced myocardial necrosis in rats

The present study investigates cardioprotective effect of Sida rhomboidea. Roxb (SR) extract on heart weight, plasma lipid profile, plasma marker enzymes, lipid peroxidation, endogenous enzymatic and non-enzymatic antioxidants and membrane bound ATPases against isoproterenol (IP) induced myocardial necrosis (MN) in rats. Rats treated with IP (85 mg/kg, s.c.) recorded significant (p<0.05) increment in heart weight, plasma lipid profile, plasma marker enzymes of cardiac damage, cardiac lipid peroxidation (LPO) and activity levels of Ca(+2) ATPase whereas there was significant (p<0.05) decrease in plasma HDL, cardiac endogenous enzymatic and non-enzymatic antioxidants, Na(+)-K(+) ATPase and Mg(+2) ATPase. Pre-treatment with SR extract (400 mg/kg per day, p.o.) for 30 consecutive days followed by IP injections on days 29th and 30th, showed significant (p<0.05) decrease in heart weight, plasma lipid profile, plasma marker enzymes of cardiac damage, cardiac lipid peroxidation, Ca(+2) ATPase and significant increase in plasma HDL, cardiac endogenous enzymatic and non-enzymatic antioxidants, Na(+)-K(+) ATPase and Mg(+2) ATPase compared to IP treated group. Hence, this study is the first scientific report on cardioprotective effect of SR against IP induced MN in rats.