Project description:Although aging associated decline of liver regeneration was discovered half a century ago, how aging contributes to the decline of liver regenerative capacity and how to improve this capacity in the elderly is still unknown. Hepatocyte plasticity is known to play a central role in the maintenance of liver regeneration; hence, we describe a strategy to explore the mechanisms underlying the relation between aging and hepatocyte plasticity: experiments with human induced-pluripotent-stem-cell–derived hepatocytes (hiPSC-Heps). Here, we established a simple and convenient method for generation of hiPSC-Heps that can maintain hepatic function for a long time with gradual accumulation of aging related markers and characteristics. We found that in contrast to rodent hepatocytes, FGF2 is essential for the plasticity of human hepatocytes, and the FGF2-activated MAPK–EZH2 axis can help to reprogram hiPSC-Heps into proliferative hepatic cells with a bipotential differentiation ability. Notably, our results showed the plasticity of hiPSC-Heps decreases with aging and this phenomenon strongly correlates with histone acetylation. Moreover, we found that selective inhibition of histone deacetylases can markedly improve the plasticity of old hiPSC-Heps and primary human hepatocytes and surprisingly increases the repopulation capacity of old PHHs in a liver injury model. Therefore, we can conclude that aging-associated histone hypoacetylation impairs hepatocyte plasticity.
Project description:Although aging associated decline of liver regeneration was discovered half a century ago, how aging contributes to the decline of liver regenerative capacity and how to improve this capacity in the elderly is still unknown. Hepatocyte plasticity is known to play a central role in the maintenance of liver regeneration; hence, we describe a strategy to explore the mechanisms underlying the relation between aging and hepatocyte plasticity: experiments with human induced-pluripotent-stem-cell–derived hepatocytes (hiPSC-Heps). Here, we established a simple and convenient method for generation of hiPSC-Heps that can maintain hepatic function for a long time with gradual accumulation of aging related markers and characteristics. We found that in contrast to rodent hepatocytes, FGF2 is essential for the plasticity of human hepatocytes, and the FGF2-activated MAPK–EZH2 axis can help to reprogram hiPSC-Heps into proliferative hepatic cells with a bipotential differentiation ability. Notably, our results showed the plasticity of hiPSC-Heps decreases with aging and this phenomenon strongly correlates with histone acetylation. Moreover, we found that selective inhibition of histone deacetylases can markedly improve the plasticity of old hiPSC-Heps and primary human hepatocytes and surprisingly increases the repopulation capacity of old PHHs in a liver injury model. Therefore, we can conclude that aging-associated histone hypoacetylation impairs hepatocyte plasticity.
Project description:Although aging associated decline of liver regeneration was discovered half a century ago, how aging contributes to the decline of liver regenerative capacity and how to improve this capacity in the elderly is still unknown. Hepatocyte plasticity is known to play a central role in the maintenance of liver regeneration; hence, we describe a strategy to explore the mechanisms underlying the relation between aging and hepatocyte plasticity: experiments with human induced-pluripotent-stem-cell–derived hepatocytes (hiPSC-Heps). Here, we established a simple and convenient method for generation of hiPSC-Heps that can maintain hepatic function for a long time with gradual accumulation of aging related markers and characteristics. We found that in contrast to rodent hepatocytes, FGF2 is essential for the plasticity of human hepatocytes, and the FGF2-activated MAPK–EZH2 axis can help to reprogram hiPSC-Heps into proliferative hepatic cells with a bipotential differentiation ability. Notably, our results showed the plasticity of hiPSC-Heps decreases with aging and this phenomenon strongly correlates with histone acetylation. Moreover, we found that selective inhibition of histone deacetylases can markedly improve the plasticity of old hiPSC-Heps and primary human hepatocytes and surprisingly increases the repopulation capacity of old PHHs in a liver injury model. Therefore, we can conclude that aging-associated histone hypoacetylation impairs hepatocyte plasticity.
Project description:To examine gene expression changes duging aging in polyploid and diploid hepatocytes, diploid and polyploid hepatocytes were sorted from young and aged multi-reporter mice and their gene expressions were analyzed by high-throughput RNA sequence.
Project description:We show that traumatic stress experienced by males in early postnatal life impairs memory in their offspring, blocks long-term potentiation (LTP) and favors long-term depression (LTD). These effects are accompanied by suppression of key molecular pathways involved in neuronal plasticity both at rest and after acute stress. Male mice were exposed to chronic traumatic stress in early postnatal life and were later bred to naM-CM-/ve females to produce second-generation offspring. Memory performance was evaluated in the offspring, and synaptic plasticity was examined in the hippocampus and the amygdala, brain areas important for memory formation. The two groups tested were 1: offspring of fathers which were stressed (MSUS - maternal separation unpredictable stress) and 2: offspring of non-stressed fathers (control). Genome-wide gene expression in hippocampus of these two groups was assessed at rest (this study) and after acute stress.
Project description:We show that traumatic stress experienced by males in early postnatal life impairs memory in their offspring, blocks long-term potentiation (LTP) and favors long-term depression (LTD). These effects are accompanied by suppression of key molecular pathways involved in neuronal plasticity both at rest and after acute stress. Male mice were exposed to chronic traumatic stress in early postnatal life and were later bred to naM-CM-/ve females to produce second-generation offspring. Memory performance was evaluated in the offspring, and synaptic plasticity was examined in the hippocampus and the amygdala, brain areas important for memory formation. The two groups tested were 1: offspring of fathers which were stressed (MSUS - maternal separation unpredictable stress) and 2: offspring of non-stressed fathers (control). Genome-wide gene expression in hippocampus of these two groups was assessed at rest and after acute stress (this study).