Aaron Rose - Academia.edu (original) (raw)

Papers by Aaron Rose

Research paper thumbnail of Calpastatin is a crucial regulator of macrophage activation that limits in vivo inflammation

The Journal of Immunology, May 1, 2012

Research paper thumbnail of Calpain-2 Inhibitor Therapy Reduces Murine Colitis and Colitis-associated Cancer

Inflammatory bowel diseases, Jan 12, 2015

An important role has emerged for calpain enzymes in regulating inflammation with one isoform, ca... more An important role has emerged for calpain enzymes in regulating inflammation with one isoform, calpain-2, particularly important for macrophage activation. The goal of this study was to determine the therapeutic potential of a synthetic calpain-2 inhibitor, zLLY-CH2F, for colitis and inflammation-associated colorectal cancer. Mice were then subjected to the azoxymethane/dextran sulfate sodium model of colitis and colitis-associated cancer incorporating intervention with daily injections of 0.75 mg/kg calpain-2 inhibitor beginning after the first signs of colitis. Calpain-2 inhibitor treatment alleviated weight loss and bloody diarrhea, and reduced inflammatory infiltration into colon tissues and inflammatory cytokine mRNA. Calpain-2 inhibitor intervention also reduced total colitis-associated cancer tumor volume by up to 70% in vehicle control mice and decreased cancer pathology scores of blinded histological colon tissue analyses. Mechanistic investigations showed that calpain-2 in...

Research paper thumbnail of Adjuvants may reduce in vivo transfection levels for DNA vaccination in mice leading to reduced antigen-specific CD8(+) T cell responses

Human vaccines & immunotherapeutics, Jan 19, 2015

Adjuvants for DNA vaccination are designed to promote transformation of transgenes into target ce... more Adjuvants for DNA vaccination are designed to promote transformation of transgenes into target cells and increase inflammation in the site of injection, with resultant immune cell recruitment. Numerous studies indicated cationic liposomes as effective adjuvants for DNA vaccination due to their ability to promote in vivo transfection and innate immune system activation. Commercial reagents as Adjuplex and in vivo-JetPEI are also intended to facilitate DNA vaccination. Here, we evaluate the adjuvant properties of cationic liposomes, Adjuplex and in vivo-JetPEI compared to injection of DNA without adjuvant. In mice vaccinated with piggyBac pDNA vaccines, we assessed in vivo antigen expression, innate immune responses in draining lymph nodes, and antigen-specific T cell responses in spleens and blood. Surprisingly, vaccination with DNA in PBS emerged as the most efficient in promoting in vivo transfection and consequent antigen expression, while the addition of adjuvant reduced the amou...

Research paper thumbnail of Preclinical development of HIvax: human survivin Highly Immunogenic vaccines

Human Vaccines & Immunotherapeutics, 2015

Our previous work involved the development of a recombinant fowlpox virus encoding survivin (FP-s... more Our previous work involved the development of a recombinant fowlpox virus encoding survivin (FP-surv) vaccine that was evaluated for efficacy in mesothelioma mouse models. Results showed that FP-surv vaccination generated significant immune responses, which led to delayed tumor growth and improved animal survival. We have extended those previous findings in the current study, which involves the pre-clinical development of an optimized version of FP-surv designed for human immunization (HIvax). Survivin-derived peptides for the most common haplotypes in the human population were identified and their immunogenicity confirmed in co-culture experiments using dendritic cells and T cells isolated from healthy donors. Peptides confirmed to induce CD8(+) and CD4(+) T cells activation in humans were then included in 2 transgenes optimized for presentation of processed peptides on MHC-I (HIvax1) and MHC-II (HIvax2). Fowlpox vectors expressing the HIvax transgenes were then generated and their efficacy was evaluated with subsequent co-culture experiments to measure interferon-γ and granzyme B secretion. In these experiments, both antigen specific CD4(+) and CD8(+) T cells were activated by HIvax vaccines with resultant cytotoxic activity against survivin-overexpressing mesothelioma cancer cells. These results provide a rationale for clinical testing of HIvax1 and HIvax2 vaccines in patients with survivin-expressing cancers.

Research paper thumbnail of Selenoproteins and cardiovascular stress

Thrombosis and haemostasis, Jan 30, 2014

Dietary selenium (Se) is an essential micronutrient that exerts its biological effects through it... more Dietary selenium (Se) is an essential micronutrient that exerts its biological effects through its incorporation into selenoproteins. This family of proteins contains several antioxidant enzymes such as the glutathione peroxidases, redox-regulating enzymes such as thioredoxin reductases, a methionine sulfoxide reductase, and others. In this review, we summarise the current understanding of the roles these selenoproteins play in protecting the cardiovascular system from different types of stress including ischaemia-reperfusion, homocysteine dysregulation, myocardial hypertrophy, doxirubicin toxicity, Keshan disease, and others.

Research paper thumbnail of Stable expression and function of the inositol 1,4,5-triphosphate receptor requires palmitoylation by a DHHC6/selenoprotein K complex

Proceedings of the National Academy of Sciences of the United States of America, Jan 18, 2014

Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic ret... more Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic reticulum (ER) stores via inositol 1,4,5-triphosphate (IP3) binding to the IP3 receptor (IP3R) is particularly important for the activation and function of immune cells. Previous studies demonstrated that genetic deletion of selenoprotein K (Selk) led to decreased Ca(2+) flux in a variety of immune cells and impaired immunity, but the mechanism was unclear. Here we show that Selk deficiency does not affect receptor-induced IP3 production, but Selk deficiency through genetic deletion or low selenium in culture media leads to low expression of the IP3R due to a defect in IP3R palmitoylation. Bioinformatic analysis of the DHHC (letters represent the amino acids aspartic acid, histidine, histidine, and cysteine in the catalytic domain) family of enzymes that catalyze protein palmitoylation revealed that one member, DHHC6, contains a predicted Src-homology 3 (SH3) domain and DHHC6 is localized t...

Research paper thumbnail of Vaccination with a piggyBac plasmid with transgene integration potential leads to sustained antigen expression and CD8+ T cell responses

Research paper thumbnail of Selenoprotein K is required for palmitoylation of CD36 in macrophages: implications in foam cell formation and atherogenesis

Journal of Leukocyte Biology, 2013

Selk is an ER transmembrane protein important for calcium flux and macrophage activation, but its... more Selk is an ER transmembrane protein important for calcium flux and macrophage activation, but its role in foam cell formation and atherosclerosis has not been evaluated. BMDMs from Selk(-/-) mice exhibited decreased uptake of modLDL and foam cell formation compared with WT controls, and the differences were eliminated with anti-CD36 blocking antibody. CD36 expression was decreased in TNF-α-stimulated Selk(-/-) BMDMs compared with WT controls. Fluorescence microscopy revealed TNF-α-induced clustering of CD36 in WT BMDMs indicative of lipid raft localization, which was absent in Selk(-/-) BMDMs. Fractionation revealed lower levels of CD36 reaching lipid rafts in TNF-α-stimulated Selk(-/-) BMDMs. Immunoprecipitation showed that Selk(-/-) BMDMs have decreased CD36 palmitoylation, which occurs at the ER membrane and is crucial for stabilizing CD36 expression and directing its localization to lipid rafts. To assess if this phenomenon had a role in atherogenesis, a HFD was fed to irradiated Ldlr(-/-) mice reconstituted with BM from Selk(-/-) or WT mice. Selk was detected in aortic plaques of controls, particularly in macrophages. Selk(-/-) in immune cells led to reduction in atherosclerotic lesion formation without affecting leukocyte migration into the arterial wall. These findings suggest that Selk is important for stable, localized expression of CD36 in macrophages during inflammation, thereby contributing to foam cell formation and atherogenesis.

Research paper thumbnail of Calpastatin Prevents NF- B-Mediated Hyperactivation of Macrophages and Attenuates Colitis

The Journal of Immunology, 2013

Research paper thumbnail of Fowlpox-based survivin vaccination for malignant mesothelioma therapy

International Journal of Cancer, 2013

Survivin protein is an attractive candidate for cancer immunotherapy since it is abundantly expre... more Survivin protein is an attractive candidate for cancer immunotherapy since it is abundantly expressed in most common human cancers and mostly absent in normal adult tissues. Malignant mesothelioma (MM) is a deadly cancer associated with asbestos or erionite exposure for which no successful therapies are currently available. In this study, we evaluated the therapeutic efficacy of a novel survivin-based vaccine by subcutaneous or intraperitoneum injection of BALB/c mice with murine fiber-induced MM tumor cells followed by vaccination with recombinant Fowlpox virus replicons encoding survivin. Vaccination generated significant immune responses in both models, leading to delayed tumor growth and improved animal survival. Flow cytometry and immunofluorescence analyses of tumors from vaccinated mice showed CD8 1 T-cell infiltration, and real-time PCR demonstrated increased mRNA and protein levels of immunostimulatory cytokines. Analyses of survivin peptide-pulsed spleen and lymph node cells from vaccinated mice using ELISPOT and intracellular cytokine staining confirmed antigen-specific, interferon-c-producing CD8 1 T-cell responses. In addition pentamer-based flow cytometry showed that vaccination generated survivin-specific CD8 1 T cells. Importantly, vaccination did not affect fertility or induce autoimmune abnormalities in mice. Our results demonstrate that vaccination with recombinant Fowlpox expressing survivin improves T-cell responses against aggressive MM tumors and may form the basis for promising clinical applications.

Research paper thumbnail of Specific antioxidant selenoproteins are induced in the heart during hypertrophy

Archives of Biochemistry and Biophysics, 2011

Selenium (Se) is thought to confer cardioprotective effects through the actions of antioxidant se... more Selenium (Se) is thought to confer cardioprotective effects through the actions of antioxidant selenoprotein enzymes that directly limit levels of ROS such as hydrogen peroxide (H 2 O 2 ) or that reverse oxidative damage to lipids and proteins. To determine how the selenoproteome responds to myocardial hypertrophy, two mouse models were employed: triidothyronine (T3)-or isoproterenol (ISO)-treatment. After 7 days of T3-and ISO-treatment, cardiac stress was demonstrated by increased H 2 O 2 and caspase-3 activity. Neither treatment produced significant increases in phospholipid peroxidation or TUNEL-positive cells, suggesting that antioxidant systems were protecting the cardiomyocytes from damage. Many selenoprotein mRNAs were induced by T3and ISO-treatment, with levels of methionine sulfoxide reductase 1 (MsrB1, also called SelR) mRNA showing the largest increases. MsrB enzymatic activity was also elevated in both models of cardiac stress, while glutathione peroxidase (GPx) activity and thioredoxin reductase (Trxrd) activity were moderately and nonsignificantly increased, respectively. Western blot assays revealed a marked increase in MsrB1 and moderate increases in GPx3, GPx4, and Trxrd1, particularly in T3-treated hearts. Thus, the main response of the selenoproteome during hypertrophy does not involve increased GPx1, but increased GPx3 for reducing extracellular H 2 O 2 and increased GPx4, Trxrd1, and MsrB1 for minimizing intracellular oxidative damage.

Research paper thumbnail of The Role of Selenium in Inflammation and Immunity: From Molecular Mechanisms to Therapeutic Opportunities

Antioxidants & Redox Signaling, 2012

Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important ... more Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in some cases. In this comprehensivearticle, the roles of Se and individual selenoproteins in regulating immune cell signaling and function are discussed. Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells. Data obtained from cell culture and animal models are reviewed and compared with those involving human physiology and pathophysiology, including the effects of Se levels on inflammatory or immune-related diseases including anti-viral immunity, autoimmunity, sepsis, allergic asthma, and chronic inflammatory disorders. Finally, the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders are discussed. Antioxid. Redox Signal. 16, 705-743.

Research paper thumbnail of Increasing Dietary Selenium Elevates Reducing Capacity and ERK Activation Associated with Accelerated Progression of Select Mesothelioma Tumors

The American Journal of Pathology, 2014

To study the effect of the micronutrient selenium on malignant mesothelioma (MM) progression, we ... more To study the effect of the micronutrient selenium on malignant mesothelioma (MM) progression, we cultured four different MM cell lines in media containing increasing amounts of sodium selenite (30, 50, and 80 nmol/L). Increasing selenium levels increased density-dependent proliferation and mobility for CRH5 and EKKH5 but not AB12 and AK7. Comparing these cell lines revealed that extracellular regulated kinase (ERK) phosphorylation was sensitive to a selenium increase in CRH5 and EKKH5 but not AB12 and AK7 cells. Stable expression of a dominant-negative mutant ERK eliminated the effects of increasing selenium. Because ERK is redox sensitive, we compared the MM cell lines in terms of glutathione levels and the capacity to reduce exogenous hydrogen peroxide. Increasing selenium levels led to higher glutathione and reducing capacity in CRH5 and EKKH5 but not AB12 and AK7. The reducing agent N-acetylcysteine eliminated the effects of selenium on ERK activation, proliferation, and mobility. Mice fed diets containing increasing levels of selenium (0.08, 0.25, and 1.0 ppm) showed increased tumor progression for CRH5 but not AB12, MM cells, and in vivo N-acetylcysteine treatment eliminated these effects. These data suggest that the effects of dietary selenium on MM tumor progression depend on the arising cancer cells' redox metabolism, and the tumors able to convert increased selenium into a stronger reducing capacity actually benefit from increased selenium intake. (Am J Pathol 2014, 184: 1041e1049; http://dx.

Research paper thumbnail of Calpastatin is a crucial regulator of macrophage activation that limits in vivo inflammation

The Journal of Immunology, May 1, 2012

Research paper thumbnail of Calpain-2 Inhibitor Therapy Reduces Murine Colitis and Colitis-associated Cancer

Inflammatory bowel diseases, Jan 12, 2015

An important role has emerged for calpain enzymes in regulating inflammation with one isoform, ca... more An important role has emerged for calpain enzymes in regulating inflammation with one isoform, calpain-2, particularly important for macrophage activation. The goal of this study was to determine the therapeutic potential of a synthetic calpain-2 inhibitor, zLLY-CH2F, for colitis and inflammation-associated colorectal cancer. Mice were then subjected to the azoxymethane/dextran sulfate sodium model of colitis and colitis-associated cancer incorporating intervention with daily injections of 0.75 mg/kg calpain-2 inhibitor beginning after the first signs of colitis. Calpain-2 inhibitor treatment alleviated weight loss and bloody diarrhea, and reduced inflammatory infiltration into colon tissues and inflammatory cytokine mRNA. Calpain-2 inhibitor intervention also reduced total colitis-associated cancer tumor volume by up to 70% in vehicle control mice and decreased cancer pathology scores of blinded histological colon tissue analyses. Mechanistic investigations showed that calpain-2 in...

Research paper thumbnail of Adjuvants may reduce in vivo transfection levels for DNA vaccination in mice leading to reduced antigen-specific CD8(+) T cell responses

Human vaccines & immunotherapeutics, Jan 19, 2015

Adjuvants for DNA vaccination are designed to promote transformation of transgenes into target ce... more Adjuvants for DNA vaccination are designed to promote transformation of transgenes into target cells and increase inflammation in the site of injection, with resultant immune cell recruitment. Numerous studies indicated cationic liposomes as effective adjuvants for DNA vaccination due to their ability to promote in vivo transfection and innate immune system activation. Commercial reagents as Adjuplex and in vivo-JetPEI are also intended to facilitate DNA vaccination. Here, we evaluate the adjuvant properties of cationic liposomes, Adjuplex and in vivo-JetPEI compared to injection of DNA without adjuvant. In mice vaccinated with piggyBac pDNA vaccines, we assessed in vivo antigen expression, innate immune responses in draining lymph nodes, and antigen-specific T cell responses in spleens and blood. Surprisingly, vaccination with DNA in PBS emerged as the most efficient in promoting in vivo transfection and consequent antigen expression, while the addition of adjuvant reduced the amou...

Research paper thumbnail of Preclinical development of HIvax: human survivin Highly Immunogenic vaccines

Human Vaccines & Immunotherapeutics, 2015

Our previous work involved the development of a recombinant fowlpox virus encoding survivin (FP-s... more Our previous work involved the development of a recombinant fowlpox virus encoding survivin (FP-surv) vaccine that was evaluated for efficacy in mesothelioma mouse models. Results showed that FP-surv vaccination generated significant immune responses, which led to delayed tumor growth and improved animal survival. We have extended those previous findings in the current study, which involves the pre-clinical development of an optimized version of FP-surv designed for human immunization (HIvax). Survivin-derived peptides for the most common haplotypes in the human population were identified and their immunogenicity confirmed in co-culture experiments using dendritic cells and T cells isolated from healthy donors. Peptides confirmed to induce CD8(+) and CD4(+) T cells activation in humans were then included in 2 transgenes optimized for presentation of processed peptides on MHC-I (HIvax1) and MHC-II (HIvax2). Fowlpox vectors expressing the HIvax transgenes were then generated and their efficacy was evaluated with subsequent co-culture experiments to measure interferon-γ and granzyme B secretion. In these experiments, both antigen specific CD4(+) and CD8(+) T cells were activated by HIvax vaccines with resultant cytotoxic activity against survivin-overexpressing mesothelioma cancer cells. These results provide a rationale for clinical testing of HIvax1 and HIvax2 vaccines in patients with survivin-expressing cancers.

Research paper thumbnail of Selenoproteins and cardiovascular stress

Thrombosis and haemostasis, Jan 30, 2014

Dietary selenium (Se) is an essential micronutrient that exerts its biological effects through it... more Dietary selenium (Se) is an essential micronutrient that exerts its biological effects through its incorporation into selenoproteins. This family of proteins contains several antioxidant enzymes such as the glutathione peroxidases, redox-regulating enzymes such as thioredoxin reductases, a methionine sulfoxide reductase, and others. In this review, we summarise the current understanding of the roles these selenoproteins play in protecting the cardiovascular system from different types of stress including ischaemia-reperfusion, homocysteine dysregulation, myocardial hypertrophy, doxirubicin toxicity, Keshan disease, and others.

Research paper thumbnail of Stable expression and function of the inositol 1,4,5-triphosphate receptor requires palmitoylation by a DHHC6/selenoprotein K complex

Proceedings of the National Academy of Sciences of the United States of America, Jan 18, 2014

Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic ret... more Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic reticulum (ER) stores via inositol 1,4,5-triphosphate (IP3) binding to the IP3 receptor (IP3R) is particularly important for the activation and function of immune cells. Previous studies demonstrated that genetic deletion of selenoprotein K (Selk) led to decreased Ca(2+) flux in a variety of immune cells and impaired immunity, but the mechanism was unclear. Here we show that Selk deficiency does not affect receptor-induced IP3 production, but Selk deficiency through genetic deletion or low selenium in culture media leads to low expression of the IP3R due to a defect in IP3R palmitoylation. Bioinformatic analysis of the DHHC (letters represent the amino acids aspartic acid, histidine, histidine, and cysteine in the catalytic domain) family of enzymes that catalyze protein palmitoylation revealed that one member, DHHC6, contains a predicted Src-homology 3 (SH3) domain and DHHC6 is localized t...

Research paper thumbnail of Vaccination with a piggyBac plasmid with transgene integration potential leads to sustained antigen expression and CD8+ T cell responses

Research paper thumbnail of Selenoprotein K is required for palmitoylation of CD36 in macrophages: implications in foam cell formation and atherogenesis

Journal of Leukocyte Biology, 2013

Selk is an ER transmembrane protein important for calcium flux and macrophage activation, but its... more Selk is an ER transmembrane protein important for calcium flux and macrophage activation, but its role in foam cell formation and atherosclerosis has not been evaluated. BMDMs from Selk(-/-) mice exhibited decreased uptake of modLDL and foam cell formation compared with WT controls, and the differences were eliminated with anti-CD36 blocking antibody. CD36 expression was decreased in TNF-α-stimulated Selk(-/-) BMDMs compared with WT controls. Fluorescence microscopy revealed TNF-α-induced clustering of CD36 in WT BMDMs indicative of lipid raft localization, which was absent in Selk(-/-) BMDMs. Fractionation revealed lower levels of CD36 reaching lipid rafts in TNF-α-stimulated Selk(-/-) BMDMs. Immunoprecipitation showed that Selk(-/-) BMDMs have decreased CD36 palmitoylation, which occurs at the ER membrane and is crucial for stabilizing CD36 expression and directing its localization to lipid rafts. To assess if this phenomenon had a role in atherogenesis, a HFD was fed to irradiated Ldlr(-/-) mice reconstituted with BM from Selk(-/-) or WT mice. Selk was detected in aortic plaques of controls, particularly in macrophages. Selk(-/-) in immune cells led to reduction in atherosclerotic lesion formation without affecting leukocyte migration into the arterial wall. These findings suggest that Selk is important for stable, localized expression of CD36 in macrophages during inflammation, thereby contributing to foam cell formation and atherogenesis.

Research paper thumbnail of Calpastatin Prevents NF- B-Mediated Hyperactivation of Macrophages and Attenuates Colitis

The Journal of Immunology, 2013

Research paper thumbnail of Fowlpox-based survivin vaccination for malignant mesothelioma therapy

International Journal of Cancer, 2013

Survivin protein is an attractive candidate for cancer immunotherapy since it is abundantly expre... more Survivin protein is an attractive candidate for cancer immunotherapy since it is abundantly expressed in most common human cancers and mostly absent in normal adult tissues. Malignant mesothelioma (MM) is a deadly cancer associated with asbestos or erionite exposure for which no successful therapies are currently available. In this study, we evaluated the therapeutic efficacy of a novel survivin-based vaccine by subcutaneous or intraperitoneum injection of BALB/c mice with murine fiber-induced MM tumor cells followed by vaccination with recombinant Fowlpox virus replicons encoding survivin. Vaccination generated significant immune responses in both models, leading to delayed tumor growth and improved animal survival. Flow cytometry and immunofluorescence analyses of tumors from vaccinated mice showed CD8 1 T-cell infiltration, and real-time PCR demonstrated increased mRNA and protein levels of immunostimulatory cytokines. Analyses of survivin peptide-pulsed spleen and lymph node cells from vaccinated mice using ELISPOT and intracellular cytokine staining confirmed antigen-specific, interferon-c-producing CD8 1 T-cell responses. In addition pentamer-based flow cytometry showed that vaccination generated survivin-specific CD8 1 T cells. Importantly, vaccination did not affect fertility or induce autoimmune abnormalities in mice. Our results demonstrate that vaccination with recombinant Fowlpox expressing survivin improves T-cell responses against aggressive MM tumors and may form the basis for promising clinical applications.

Research paper thumbnail of Specific antioxidant selenoproteins are induced in the heart during hypertrophy

Archives of Biochemistry and Biophysics, 2011

Selenium (Se) is thought to confer cardioprotective effects through the actions of antioxidant se... more Selenium (Se) is thought to confer cardioprotective effects through the actions of antioxidant selenoprotein enzymes that directly limit levels of ROS such as hydrogen peroxide (H 2 O 2 ) or that reverse oxidative damage to lipids and proteins. To determine how the selenoproteome responds to myocardial hypertrophy, two mouse models were employed: triidothyronine (T3)-or isoproterenol (ISO)-treatment. After 7 days of T3-and ISO-treatment, cardiac stress was demonstrated by increased H 2 O 2 and caspase-3 activity. Neither treatment produced significant increases in phospholipid peroxidation or TUNEL-positive cells, suggesting that antioxidant systems were protecting the cardiomyocytes from damage. Many selenoprotein mRNAs were induced by T3and ISO-treatment, with levels of methionine sulfoxide reductase 1 (MsrB1, also called SelR) mRNA showing the largest increases. MsrB enzymatic activity was also elevated in both models of cardiac stress, while glutathione peroxidase (GPx) activity and thioredoxin reductase (Trxrd) activity were moderately and nonsignificantly increased, respectively. Western blot assays revealed a marked increase in MsrB1 and moderate increases in GPx3, GPx4, and Trxrd1, particularly in T3-treated hearts. Thus, the main response of the selenoproteome during hypertrophy does not involve increased GPx1, but increased GPx3 for reducing extracellular H 2 O 2 and increased GPx4, Trxrd1, and MsrB1 for minimizing intracellular oxidative damage.

Research paper thumbnail of The Role of Selenium in Inflammation and Immunity: From Molecular Mechanisms to Therapeutic Opportunities

Antioxidants & Redox Signaling, 2012

Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important ... more Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in some cases. In this comprehensivearticle, the roles of Se and individual selenoproteins in regulating immune cell signaling and function are discussed. Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells. Data obtained from cell culture and animal models are reviewed and compared with those involving human physiology and pathophysiology, including the effects of Se levels on inflammatory or immune-related diseases including anti-viral immunity, autoimmunity, sepsis, allergic asthma, and chronic inflammatory disorders. Finally, the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders are discussed. Antioxid. Redox Signal. 16, 705-743.

Research paper thumbnail of Increasing Dietary Selenium Elevates Reducing Capacity and ERK Activation Associated with Accelerated Progression of Select Mesothelioma Tumors

The American Journal of Pathology, 2014

To study the effect of the micronutrient selenium on malignant mesothelioma (MM) progression, we ... more To study the effect of the micronutrient selenium on malignant mesothelioma (MM) progression, we cultured four different MM cell lines in media containing increasing amounts of sodium selenite (30, 50, and 80 nmol/L). Increasing selenium levels increased density-dependent proliferation and mobility for CRH5 and EKKH5 but not AB12 and AK7. Comparing these cell lines revealed that extracellular regulated kinase (ERK) phosphorylation was sensitive to a selenium increase in CRH5 and EKKH5 but not AB12 and AK7 cells. Stable expression of a dominant-negative mutant ERK eliminated the effects of increasing selenium. Because ERK is redox sensitive, we compared the MM cell lines in terms of glutathione levels and the capacity to reduce exogenous hydrogen peroxide. Increasing selenium levels led to higher glutathione and reducing capacity in CRH5 and EKKH5 but not AB12 and AK7. The reducing agent N-acetylcysteine eliminated the effects of selenium on ERK activation, proliferation, and mobility. Mice fed diets containing increasing levels of selenium (0.08, 0.25, and 1.0 ppm) showed increased tumor progression for CRH5 but not AB12, MM cells, and in vivo N-acetylcysteine treatment eliminated these effects. These data suggest that the effects of dietary selenium on MM tumor progression depend on the arising cancer cells' redox metabolism, and the tumors able to convert increased selenium into a stronger reducing capacity actually benefit from increased selenium intake. (Am J Pathol 2014, 184: 1041e1049; http://dx.