The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Thomas A Rando - One of the best experts on this subject based on the ideXlab platform.
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heterochronic Parabiosis historical perspective and methodological considerations for studies of aging and longevity
Aging Cell, 2013Co-Authors: Michael J. Conboy, Irina M. Conboy, Thomas A RandoAbstract:Pairing two animals in Parabiosis to test for systemic or circulatory factors from one animal affecting the other animal has been used in scientific studies for at least 150 years. These studies have led to advances in fields as diverse as endocrinology, immunology, and oncology. A variation on the technique, heterochronic Parabiosis, whereby two animals of different ages are joined to test for systemic regulators of aspects of aging or age-related diseases also has almost a century-long scientific history. In this review, we focus on the history of heterochronic Parabiosis, methodological considerations and caveats, and the major advances that have emerged from those studies, including recent advances in our understanding of stem cell aging.
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rejuvenation of aged progenitor cells by exposure to a young systemic environment
Nature, 2005Co-Authors: Irina M. Conboy, Eric R. Girma, Amy J. Wagers, Michael J. Conboy, Irving L Weissman, Thomas A RandoAbstract:Tissues of the body regenerate well in young individuals, less so in older individuals. To find out if this decline is irreversible, or subject to factors in the circulation, Conboy et al. joined together the circulatory systems of young and old mice, as a ‘parabiotic’ pair. Strikingly, regenerative properties of aged muscle and liver were rejuvenated by the serum from younger animals. At the same time there was a restoration of young ‘molecular signatures’, involving Notch signalling (in muscle) and cEBPa-mediated cell cycle regulation (in liver). This suggests that stem and progenitor cells retain proliferative potential even when old, and that the ‘young’ pattern of molecular signalling can reactivate tissue regeneration. The decline of tissue regenerative potential is a hallmark of ageing and may be due to age-related changes in tissue-specific stem cells1,2,3,4,5. A decline in skeletal muscle stem cell (satellite cell) activity due to a loss of Notch signalling results in impaired regeneration of aged muscle1,6. The decline in hepatic progenitor cell proliferation owing to the formation of a complex involving cEBP-α and the chromatin remodelling factor brahma (Brm) inhibits the regenerative capacity of aged liver7. To examine the influence of systemic factors on aged progenitor cells from these tissues, we established parabiotic pairings (that is, a shared circulatory system) between young and old mice (heterochronic parabioses), exposing old mice to factors present in young serum. Notably, heterochronic Parabiosis restored the activation of Notch signalling as well as the proliferation and regenerative capacity of aged satellite cells. The exposure of satellite cells from old mice to young serum enhanced the expression of the Notch ligand (Delta), increased Notch activation, and enhanced proliferation in vitro. Furthermore, heterochronic Parabiosis increased aged hepatocyte proliferation and restored the cEBP-α complex to levels seen in young animals. These results suggest that the age-related decline of progenitor cell activity can be modulated by systemic factors that change with age.
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Rejuvenation of aged progenitor cells by exposure to a young systemic environment
Nature, 2005Co-Authors: Irina M. Conboy, Eric R. Girma, Irving L. Weismann, Amy J. Wagers, Michael J. Conboy, Thomas A RandoAbstract:The decline of tissue regenerative potential is a hallmark of ageing and may be due to age-related changes in tissue-specific stem cells. A decline in skeletal muscle stem cell (satellite cell) activity due to a loss of Notch signalling results in impaired regeneration of aged muscle. The decline in hepatic progenitor cell proliferation owing to the formation of a complex involving cEBP-alpha and the chromatin remodelling factor brahma (Brm) inhibits the regenerative capacity of aged liver. To examine the influence of systemic factors on aged progenitor cells from these tissues, we established parabiotic pairings (that is, a shared circulatory system) between young and old mice (heterochronic parabioses), exposing old mice to factors present in young serum. Notably, heterochronic Parabiosis restored the activation of Notch signalling as well as the proliferation and regenerative capacity of aged satellite cells. The exposure of satellite cells from old mice to young serum enhanced the expression of the Notch ligand (Delta), increased Notch activation, and enhanced proliferation in vitro. Furthermore, heterochronic Parabiosis increased aged hepatocyte proliferation and restored the cEBP-alpha complex to levels seen in young animals. These results suggest that the age-related decline of progenitor cell activity can be modulated by systemic factors that change with age.
Nico Blüthgen - One of the best experts on this subject based on the ideXlab platform.
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selective interspecific tolerance in tropical crematogaster camponotus associations
Animal Behaviour, 2008Co-Authors: Florian Menzel, Karl Eduard Linsenmair, Nico BlüthgenAbstract:Associations between ants of the genera Crematogaster and Camponotus are found in many parts of the world. Associated species use common trails (trail sharing) or even share a common nest (Parabiosis). In a tropical lowland forest in Malaysian Borneo, we studied intraspecific and interspecific aggression among the parabiotic species Crematogaster modiglianii and Camponotus rufifemur using both field and laboratory assays. Cr. modiglianii tolerated Ca. rufifemur workers from certain foreign colonies but fiercely attacked those of others. In contrast, Ca. rufifemur was tolerant even towards attacking allocolonial Cr. modiglianii workers but killed other Crematogaster species. By analogy, other Camponotus species usually attacked and killed Cr. modiglianii. Intraspecific confrontations among Ca. rufifemur colonies yielded a gradient from allocolonial tolerance to strong aggression. The aggression patterns coincide with those of Cr. modiglianii towards Ca. rufifemur workers from the same colonies. Our results suggest either that Ca. rufifemur is not able to recognize allocolonial Cr. modiglianii workers as foreign or that they are recognized but tolerated. The unilateral, species-specific but not colony-specific tolerance of Ca. rufifemur towards its partner species contrasts with highly colony-specific tolerance found among neotropical parabioses.
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Selective interspecific tolerance in tropical Crematogaster–Camponotus associations
Animal Behaviour, 2008Co-Authors: Florian Menzel, Karl Eduard Linsenmair, Nico BlüthgenAbstract:Associations between ants of the genera Crematogaster and Camponotus are found in many parts of the world. Associated species use common trails (trail sharing) or even share a common nest (Parabiosis). In a tropical lowland forest in Malaysian Borneo, we studied intraspecific and interspecific aggression among the parabiotic species Crematogaster modiglianii and Camponotus rufifemur using both field and laboratory assays. Cr. modiglianii tolerated Ca. rufifemur workers from certain foreign colonies but fiercely attacked those of others. In contrast, Ca. rufifemur was tolerant even towards attacking allocolonial Cr. modiglianii workers but killed other Crematogaster species. By analogy, other Camponotus species usually attacked and killed Cr. modiglianii. Intraspecific confrontations among Ca. rufifemur colonies yielded a gradient from allocolonial tolerance to strong aggression. The aggression patterns coincide with those of Cr. modiglianii towards Ca. rufifemur workers from the same colonies. Our results suggest either that Ca. rufifemur is not able to recognize allocolonial Cr. modiglianii workers as foreign or that they are recognized but tolerated. The unilateral, species-specific but not colony-specific tolerance of Ca. rufifemur towards its partner species contrasts with highly colony-specific tolerance found among neotropical parabioses.
Irina M. Conboy - One of the best experts on this subject based on the ideXlab platform.
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Addendum: Application of bio-orthogonal proteome labeling to cell transplantation and heterochronic Parabiosis.
Nature communications, 2017Co-Authors: Yan Liu, Michael J. Conboy, Melod Mehdipour, Yutong Liu, Thanhtra P. Tran, Aaron Blotnick, Prasanna Rajan, Thalie Cavalcante Santos, Irina M. ConboyAbstract:Studies of heterochronic Parabiosis demonstrated that with age, the composition of the circulatory milieu changes in ways that broadly inhibit tissue regenerative capacity. In addition, local tissue niches have age-specific influences on their resident stem cells. Here we use bio-orthogonal proteome labeling for detecting in vivo proteins present only in transplanted myoblasts, but not in host tissue, and proteins exclusive to one young mouse and transferred during Parabiosis to its old partner. We use a transgenic mouse strain that ubiquitously expresses a modified tRNA methionine synthase, metRS, which preferentially incorporates the methionine surrogate azido-nor-leucine (ANL) into newly generated proteins. Using click chemistry and a modified antibody array to detect ANL-labeled proteins, we identify several 'young' systemic factors in old regenerating muscle of the heterochronic parabiotic partners. Our approach enables the selective profiling of mammalian proteomes in mixed biological environments such as cell and tissue transplantation, apheresis or Parabiosis.Clarifying the source of proteins in mixed biological environments, such as after transplantation or Parabiosis, remains a challenge. Here, the authors address this need with a mouse strain that incorporates a methionine derivate into proteins, allowing for their detection using click chemistry and antibody arrays.
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application of bio orthogonal proteome labeling to cell transplantation and heterochronic Parabiosis
Nature Communications, 2017Co-Authors: Michael J. Conboy, Yan Liu, Melod Mehdipour, Yutong Liu, Aaron Blotnick, Prasanna Rajan, Thalie Cavalcante Santos, Thanhtra Tran, Irina M. ConboyAbstract:Studies of heterochronic Parabiosis demonstrated that with age, the composition of the circulatory milieu changes in ways that broadly inhibit tissue regenerative capacity. In addition, local tissue niches have age-specific influences on their resident stem cells. Here we use bio-orthogonal proteome labeling for detecting in vivo proteins present only in transplanted myoblasts, but not in host tissue, and proteins exclusive to one young mouse and transferred during Parabiosis to its old partner. We use a transgenic mouse strain that ubiquitously expresses a modified tRNA methionine synthase, metRS, which preferentially incorporates the methionine surrogate azido-nor-leucine (ANL) into newly generated proteins. Using click chemistry and a modified antibody array to detect ANL-labeled proteins, we identify several 'young' systemic factors in old regenerating muscle of the heterochronic parabiotic partners. Our approach enables the selective profiling of mammalian proteomes in mixed biological environments such as cell and tissue transplantation, apheresis or Parabiosis.Clarifying the source of proteins in mixed biological environments, such as after transplantation or Parabiosis, remains a challenge. Here, the authors address this need with a mouse strain that incorporates a methionine derivate into proteins, allowing for their detection using click chemistry and antibody arrays.
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Application of bio-orthogonal proteome labeling to cell transplantation and heterochronic Parabiosis
Nature Publishing Group, 2017Co-Authors: Yan Liu, Michael J. Conboy, Melod Mehdipour, Yutong Liu, Thanhtra P. Tran, Aaron Blotnick, Prasanna Rajan, Thalie Cavalcante Santos, Irina M. ConboyAbstract:Clarifying the source of proteins in mixed biological environments, such as after transplantation or Parabiosis, remains a challenge. Here, the authors address this need with a mouse strain that incorporates a methionine derivate into proteins, allowing for their detection using click chemistry and antibody arrays
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heterochronic Parabiosis historical perspective and methodological considerations for studies of aging and longevity
Aging Cell, 2013Co-Authors: Michael J. Conboy, Irina M. Conboy, Thomas A RandoAbstract:Pairing two animals in Parabiosis to test for systemic or circulatory factors from one animal affecting the other animal has been used in scientific studies for at least 150 years. These studies have led to advances in fields as diverse as endocrinology, immunology, and oncology. A variation on the technique, heterochronic Parabiosis, whereby two animals of different ages are joined to test for systemic regulators of aspects of aging or age-related diseases also has almost a century-long scientific history. In this review, we focus on the history of heterochronic Parabiosis, methodological considerations and caveats, and the major advances that have emerged from those studies, including recent advances in our understanding of stem cell aging.
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rejuvenation of aged progenitor cells by exposure to a young systemic environment
Nature, 2005Co-Authors: Irina M. Conboy, Eric R. Girma, Amy J. Wagers, Michael J. Conboy, Irving L Weissman, Thomas A RandoAbstract:Tissues of the body regenerate well in young individuals, less so in older individuals. To find out if this decline is irreversible, or subject to factors in the circulation, Conboy et al. joined together the circulatory systems of young and old mice, as a ‘parabiotic’ pair. Strikingly, regenerative properties of aged muscle and liver were rejuvenated by the serum from younger animals. At the same time there was a restoration of young ‘molecular signatures’, involving Notch signalling (in muscle) and cEBPa-mediated cell cycle regulation (in liver). This suggests that stem and progenitor cells retain proliferative potential even when old, and that the ‘young’ pattern of molecular signalling can reactivate tissue regeneration. The decline of tissue regenerative potential is a hallmark of ageing and may be due to age-related changes in tissue-specific stem cells1,2,3,4,5. A decline in skeletal muscle stem cell (satellite cell) activity due to a loss of Notch signalling results in impaired regeneration of aged muscle1,6. The decline in hepatic progenitor cell proliferation owing to the formation of a complex involving cEBP-α and the chromatin remodelling factor brahma (Brm) inhibits the regenerative capacity of aged liver7. To examine the influence of systemic factors on aged progenitor cells from these tissues, we established parabiotic pairings (that is, a shared circulatory system) between young and old mice (heterochronic parabioses), exposing old mice to factors present in young serum. Notably, heterochronic Parabiosis restored the activation of Notch signalling as well as the proliferation and regenerative capacity of aged satellite cells. The exposure of satellite cells from old mice to young serum enhanced the expression of the Notch ligand (Delta), increased Notch activation, and enhanced proliferation in vitro. Furthermore, heterochronic Parabiosis increased aged hepatocyte proliferation and restored the cEBP-α complex to levels seen in young animals. These results suggest that the age-related decline of progenitor cell activity can be modulated by systemic factors that change with age.
Florian Menzel - One of the best experts on this subject based on the ideXlab platform.
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What makes you a potential partner? Insights from convergently evolved ant–ant symbioses
Chemoecology, 2014Co-Authors: Florian Menzel, Jérôme Orivel, Martin Kaltenpoth, Thomas SchmittAbstract:Mutualistic, commensalistic or parasitic interactions are unevenly distributed across the animals and plants: in certain taxa, such interspecific associations evolved more often than in others. Within the ants, associations between species of the genera Camponotus and Crematogaster evolved repeatedly and include trail-sharing associations, where two species share foraging trails, and parabioses, where two species share a nest without aggression. Camponotus and Crematogaster may possess life-history traits that favour the evolution of associations. To identify which traits are affected by the association, we investigated a neotropical Parabiosis of Ca. femoratus and Cr. levior and compared it to a paleotropical Parabiosis and a trail-sharing association. The two neotropical species showed altered cuticular hydrocarbon profiles compared to non-parabiotic species accompanied by low levels of interspecific aggression. Both species occurred in two chemically distinct types. Camponotus followed artificial trails of Crematogaster pheromones, but not vice versa. The above traits were also found in the paleotropical Parabiosis, and the trail-following results match those of the trail-sharing association. In contrast to paleotropical parabioses, however, Camponotus was dominant, had a high foraging activity and often fought against Crematogaster over food resources. We suggest three potential preadaptations for Parabiosis. First, Crematogaster uses molecules as trail pheromones, which can be perceived by Camponotus, too. Second, nests of Camponotus are an important benefit to Crematogaster and may create a selection pressure for the latter to tolerate Camponotus. Third, there are parallel, but unusual, shifts in cuticular hydrocarbon profiles between neotropics and paleotropics, and between Camponotus and Crematogaster.
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selective interspecific tolerance in tropical crematogaster camponotus associations
Animal Behaviour, 2008Co-Authors: Florian Menzel, Karl Eduard Linsenmair, Nico BlüthgenAbstract:Associations between ants of the genera Crematogaster and Camponotus are found in many parts of the world. Associated species use common trails (trail sharing) or even share a common nest (Parabiosis). In a tropical lowland forest in Malaysian Borneo, we studied intraspecific and interspecific aggression among the parabiotic species Crematogaster modiglianii and Camponotus rufifemur using both field and laboratory assays. Cr. modiglianii tolerated Ca. rufifemur workers from certain foreign colonies but fiercely attacked those of others. In contrast, Ca. rufifemur was tolerant even towards attacking allocolonial Cr. modiglianii workers but killed other Crematogaster species. By analogy, other Camponotus species usually attacked and killed Cr. modiglianii. Intraspecific confrontations among Ca. rufifemur colonies yielded a gradient from allocolonial tolerance to strong aggression. The aggression patterns coincide with those of Cr. modiglianii towards Ca. rufifemur workers from the same colonies. Our results suggest either that Ca. rufifemur is not able to recognize allocolonial Cr. modiglianii workers as foreign or that they are recognized but tolerated. The unilateral, species-specific but not colony-specific tolerance of Ca. rufifemur towards its partner species contrasts with highly colony-specific tolerance found among neotropical parabioses.
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Selective interspecific tolerance in tropical Crematogaster–Camponotus associations
Animal Behaviour, 2008Co-Authors: Florian Menzel, Karl Eduard Linsenmair, Nico BlüthgenAbstract:Associations between ants of the genera Crematogaster and Camponotus are found in many parts of the world. Associated species use common trails (trail sharing) or even share a common nest (Parabiosis). In a tropical lowland forest in Malaysian Borneo, we studied intraspecific and interspecific aggression among the parabiotic species Crematogaster modiglianii and Camponotus rufifemur using both field and laboratory assays. Cr. modiglianii tolerated Ca. rufifemur workers from certain foreign colonies but fiercely attacked those of others. In contrast, Ca. rufifemur was tolerant even towards attacking allocolonial Cr. modiglianii workers but killed other Crematogaster species. By analogy, other Camponotus species usually attacked and killed Cr. modiglianii. Intraspecific confrontations among Ca. rufifemur colonies yielded a gradient from allocolonial tolerance to strong aggression. The aggression patterns coincide with those of Cr. modiglianii towards Ca. rufifemur workers from the same colonies. Our results suggest either that Ca. rufifemur is not able to recognize allocolonial Cr. modiglianii workers as foreign or that they are recognized but tolerated. The unilateral, species-specific but not colony-specific tolerance of Ca. rufifemur towards its partner species contrasts with highly colony-specific tolerance found among neotropical parabioses.
Amy J. Wagers - One of the best experts on this subject based on the ideXlab platform.
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Testosterone is essential for skeletal muscle growth in aged mice in a heterochronic Parabiosis model
Cell and tissue research, 2014Co-Authors: Indranil Sinha, Amy J. Wagers, Amiya P. Sinha-hikim, Indrani Sinha-hikimAbstract:As humans age, they lose both muscle mass and strength (sarcopenia). Testosterone, a circulating hormone, progressively declines in aging and is associated with loss of muscle mass and strength. The surgical joining of a young and old mouse (heterochronic Parabiosis) activates Notch signaling and restores muscle regenerative potential in aged mice. We hypothesize that testosterone is at least one of the factors required for the improvement seen in muscles in old mice in heterochronic Parabiosis with young mice. To test this hypothesis, we established the following heterochronic parabioses between young (Y; 5 months old) and old (O; 22–23 months old) C57BL6 male mice: (1) Y:O; (2) castrated Y:O (OY:O); (3) castrated + testosterone-treated Y:O (OY + T:O). A group of normal young mice received empty implants, and old mice were used as controls. Parabiotic pairings were maintained for 4 weeks prior to analysis. Serum testosterone levels were three-fold higher in young than in old mice. The OY + T:O pairing demonstrated significantly elevated levels of serum testosterone and an improvement in gastrocnemius muscle weight, muscle ultrastructure, muscle fiber cross-sectional area, and Notch-1 expression in old mice. These changes were not present in aged mice in the OY:O pairing. These data indicate that testosterone has a critical role in mediating the improved muscle mass and ultrastructure seen in an experimental model of heterochronic Parabiosis.
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rejuvenation of aged progenitor cells by exposure to a young systemic environment
Nature, 2005Co-Authors: Irina M. Conboy, Eric R. Girma, Amy J. Wagers, Michael J. Conboy, Irving L Weissman, Thomas A RandoAbstract:Tissues of the body regenerate well in young individuals, less so in older individuals. To find out if this decline is irreversible, or subject to factors in the circulation, Conboy et al. joined together the circulatory systems of young and old mice, as a ‘parabiotic’ pair. Strikingly, regenerative properties of aged muscle and liver were rejuvenated by the serum from younger animals. At the same time there was a restoration of young ‘molecular signatures’, involving Notch signalling (in muscle) and cEBPa-mediated cell cycle regulation (in liver). This suggests that stem and progenitor cells retain proliferative potential even when old, and that the ‘young’ pattern of molecular signalling can reactivate tissue regeneration. The decline of tissue regenerative potential is a hallmark of ageing and may be due to age-related changes in tissue-specific stem cells1,2,3,4,5. A decline in skeletal muscle stem cell (satellite cell) activity due to a loss of Notch signalling results in impaired regeneration of aged muscle1,6. The decline in hepatic progenitor cell proliferation owing to the formation of a complex involving cEBP-α and the chromatin remodelling factor brahma (Brm) inhibits the regenerative capacity of aged liver7. To examine the influence of systemic factors on aged progenitor cells from these tissues, we established parabiotic pairings (that is, a shared circulatory system) between young and old mice (heterochronic parabioses), exposing old mice to factors present in young serum. Notably, heterochronic Parabiosis restored the activation of Notch signalling as well as the proliferation and regenerative capacity of aged satellite cells. The exposure of satellite cells from old mice to young serum enhanced the expression of the Notch ligand (Delta), increased Notch activation, and enhanced proliferation in vitro. Furthermore, heterochronic Parabiosis increased aged hepatocyte proliferation and restored the cEBP-α complex to levels seen in young animals. These results suggest that the age-related decline of progenitor cell activity can be modulated by systemic factors that change with age.
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Rejuvenation of aged progenitor cells by exposure to a young systemic environment
Nature, 2005Co-Authors: Irina M. Conboy, Eric R. Girma, Irving L. Weismann, Amy J. Wagers, Michael J. Conboy, Thomas A RandoAbstract:The decline of tissue regenerative potential is a hallmark of ageing and may be due to age-related changes in tissue-specific stem cells. A decline in skeletal muscle stem cell (satellite cell) activity due to a loss of Notch signalling results in impaired regeneration of aged muscle. The decline in hepatic progenitor cell proliferation owing to the formation of a complex involving cEBP-alpha and the chromatin remodelling factor brahma (Brm) inhibits the regenerative capacity of aged liver. To examine the influence of systemic factors on aged progenitor cells from these tissues, we established parabiotic pairings (that is, a shared circulatory system) between young and old mice (heterochronic parabioses), exposing old mice to factors present in young serum. Notably, heterochronic Parabiosis restored the activation of Notch signalling as well as the proliferation and regenerative capacity of aged satellite cells. The exposure of satellite cells from old mice to young serum enhanced the expression of the Notch ligand (Delta), increased Notch activation, and enhanced proliferation in vitro. Furthermore, heterochronic Parabiosis increased aged hepatocyte proliferation and restored the cEBP-alpha complex to levels seen in young animals. These results suggest that the age-related decline of progenitor cell activity can be modulated by systemic factors that change with age.
