Cryoprotectants play a key role in cell cryopreservation because they can reduce cryoinjuries to cells associated with ice formation.To meet the clinical requirements of cryopreserved cells,cryoprotectants should be b...Cryoprotectants play a key role in cell cryopreservation because they can reduce cryoinjuries to cells associated with ice formation.To meet the clinical requirements of cryopreserved cells,cryoprotectants should be biocompatible,highly efficient and easily removable from cryopreserved cells.However,integration of these properties into one cryoprotectant still remains challenging.Herein,three biocompatible neutral amino acids,includingβ-alanine,γ-aminobutyric acid andε-aminocaproic acid,are first reported to have the potential as such ideal cryoprotectants.The results demonstrate that they can inhibit ice formation and reduce osmotic stress to provide extracellular and intracellular protection,thereby ensuring high cryopreservation efficiency for both anuclear and nucleated cells.More importantly,due to the remarkable osmotic regulation ability,the neutral amino acids can be rapidly removed from cryopreserved cells via a one-step method without causing observable damage to cells,superior to the current state-of-the-art cryoprotectants—dimethyl sulfoxide and glycerol.This work provides a new perspective to develop novel cryoprotectants,which may have dramatic impacts on solvent-free cryopreservation technology to support the cell-based applications,such as cell therapy and tissue engineering,etc.展开更多
Four neutral amino acids (Gly, Ala,.Val and Leu) were separated with ligand exchange resins. The separation capacity of the ligand exchange resins is compared with that of common ion exchange resins. The effects of el...Four neutral amino acids (Gly, Ala,.Val and Leu) were separated with ligand exchange resins. The separation capacity of the ligand exchange resins is compared with that of common ion exchange resins. The effects of eluent, column temperature, and central metal ions of the support on the separation are studied. The relationship between matrix structure of resins and their separation capacity is analysed.展开更多
As the global demographic shifts toward an aging population,understanding the efficiency of protein uti-lization in older adults becomes crucial.Our study explores the intricate relationship between protein intake and...As the global demographic shifts toward an aging population,understanding the efficiency of protein uti-lization in older adults becomes crucial.Our study explores the intricate relationship between protein intake and aging,with a focus on precision nutrition for older people.Through a meta-analysis,we con-firm a decline in protein-utilization capacity in older individuals and examine the different contributions of plant and animal protein.In experiments involving mice of different ages,older mice exhibited decreases in the biological utilization of four proteins(casein,beef protein,soy protein,and gluten),par-ticularly casein.In subsequent research,casein was studied as a key protein.A decline in gastric digestion function was observed through peptidomics and the examination of pepsin levels using casein.Nevertheless,this decline did not significantly affect the overall protein digestion during the aging pro-cess.The combined application of targeted amino acid metabolomics identified abnormal absorption of amino acids as the underlying cause of decreased protein utilization during aging,particularly emphasiz-ing a reduction in branched-chain amino acids(BCAAs)in older mice.Delving deeper into the proteomics of the intestinal protein digestion and absorption pathway,a reduction of over 60%in large neutral amino acid transporter 2(LAT2)protein expression was observed in both older humans and aged mice.The reduction in LAT2 protein was found to be a key factor influencing the diminished BCAA availability.Overall,our study establishes the significance of amino acid absorption through LAT2 in protein utiliza-tion during aging and offers a new theoretical foundation for improving protein utilization in the older adults.展开更多
Sodium-coupled neutral amino acid transporter 2(SNAT2),also known as solute carrier family 38 member 2(SLC38 A2),is expressed in the skeletal muscle.Our research previously indicated that SNAT2 m RNA expression level ...Sodium-coupled neutral amino acid transporter 2(SNAT2),also known as solute carrier family 38 member 2(SLC38 A2),is expressed in the skeletal muscle.Our research previously indicated that SNAT2 m RNA expression level in the skeletal muscle was modulated by genotype and dietary protein.The aim of this study was to investigate the key role of the amino acid transporter SNAT2 in muscle cell growth,differentiation,and related signaling pathways via SNAT2 suppression using the inhibitor a-methylaminoisobutyric acid(Me AIB).The results showed that SNAT2 suppression down-regulated both the m RNA and protein expression levels of SNAT2 in C2 C12 cells,inhibited cell viability and differentiation of the cell,and regulated the cell distribution in G0/G1 and S phases(P<0.05).Meanwhile,most of the intercellular amino acid content of the cells after Me AIB co-culturing was significantly lower(P<0.05).Furthermore,the m RNA expression levels of system L amino acid transporter 1(LAT1),silent information regulator 1,and peroxisome proliferator-activated receptor-gamma co-activator 1 alpha,as well as the protein expression levels of amino acid transporters LAT1 and vacuolar protein sorting 34,were all down-regulated.The phosphorylated protein expression levels of mammalian target of rapamycin(m TOR),regulatory-associated protein of m TOR,4 E binding protein 1,and ribosomal protein S6 kinase 1 after Me AIB treatment were also significantly down-regulated(P<0.05),which could contribute to the importance of SNAT2 in amino acid transportation and skeletal muscle cell sensing.In conclusion,SNAT2 suppression inhibited C2 C12 cell growth and differentiation,as well as the availability of free amino acids.Although the m TOR complex 1 signaling pathway was found to be involved,its response to different nutrients requires further study.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.21621004,21961132005,21908160 and 21422605)the Qingdao National Laboratory for Marine Science and Technology(QNLM2016ORP0407)+1 种基金the Tianjin Natural Science Foundation(18JCYBJC29500)the China Postdoctoral Science Foundation(2019M651041)。
文摘Cryoprotectants play a key role in cell cryopreservation because they can reduce cryoinjuries to cells associated with ice formation.To meet the clinical requirements of cryopreserved cells,cryoprotectants should be biocompatible,highly efficient and easily removable from cryopreserved cells.However,integration of these properties into one cryoprotectant still remains challenging.Herein,three biocompatible neutral amino acids,includingβ-alanine,γ-aminobutyric acid andε-aminocaproic acid,are first reported to have the potential as such ideal cryoprotectants.The results demonstrate that they can inhibit ice formation and reduce osmotic stress to provide extracellular and intracellular protection,thereby ensuring high cryopreservation efficiency for both anuclear and nucleated cells.More importantly,due to the remarkable osmotic regulation ability,the neutral amino acids can be rapidly removed from cryopreserved cells via a one-step method without causing observable damage to cells,superior to the current state-of-the-art cryoprotectants—dimethyl sulfoxide and glycerol.This work provides a new perspective to develop novel cryoprotectants,which may have dramatic impacts on solvent-free cryopreservation technology to support the cell-based applications,such as cell therapy and tissue engineering,etc.
文摘Four neutral amino acids (Gly, Ala,.Val and Leu) were separated with ligand exchange resins. The separation capacity of the ligand exchange resins is compared with that of common ion exchange resins. The effects of eluent, column temperature, and central metal ions of the support on the separation are studied. The relationship between matrix structure of resins and their separation capacity is analysed.
基金funded by the National Key Research and Development Program of China(2023YFF1104502)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2022QNRC001).
文摘As the global demographic shifts toward an aging population,understanding the efficiency of protein uti-lization in older adults becomes crucial.Our study explores the intricate relationship between protein intake and aging,with a focus on precision nutrition for older people.Through a meta-analysis,we con-firm a decline in protein-utilization capacity in older individuals and examine the different contributions of plant and animal protein.In experiments involving mice of different ages,older mice exhibited decreases in the biological utilization of four proteins(casein,beef protein,soy protein,and gluten),par-ticularly casein.In subsequent research,casein was studied as a key protein.A decline in gastric digestion function was observed through peptidomics and the examination of pepsin levels using casein.Nevertheless,this decline did not significantly affect the overall protein digestion during the aging pro-cess.The combined application of targeted amino acid metabolomics identified abnormal absorption of amino acids as the underlying cause of decreased protein utilization during aging,particularly emphasiz-ing a reduction in branched-chain amino acids(BCAAs)in older mice.Delving deeper into the proteomics of the intestinal protein digestion and absorption pathway,a reduction of over 60%in large neutral amino acid transporter 2(LAT2)protein expression was observed in both older humans and aged mice.The reduction in LAT2 protein was found to be a key factor influencing the diminished BCAA availability.Overall,our study establishes the significance of amino acid absorption through LAT2 in protein utiliza-tion during aging and offers a new theoretical foundation for improving protein utilization in the older adults.
基金financially supported by the National Key R&D Program(2018YFD0500405)the Science and technology projects of Changsha City(kq1801059)+2 种基金the STS regional key projects of Chinese Academy of Sciences(KFJ-STS-QYZD-052)the Youth Innovation Promotion Association CAS(2016326)the Earmarked Fund for China Agriculture Research System(CARS-35)
文摘Sodium-coupled neutral amino acid transporter 2(SNAT2),also known as solute carrier family 38 member 2(SLC38 A2),is expressed in the skeletal muscle.Our research previously indicated that SNAT2 m RNA expression level in the skeletal muscle was modulated by genotype and dietary protein.The aim of this study was to investigate the key role of the amino acid transporter SNAT2 in muscle cell growth,differentiation,and related signaling pathways via SNAT2 suppression using the inhibitor a-methylaminoisobutyric acid(Me AIB).The results showed that SNAT2 suppression down-regulated both the m RNA and protein expression levels of SNAT2 in C2 C12 cells,inhibited cell viability and differentiation of the cell,and regulated the cell distribution in G0/G1 and S phases(P<0.05).Meanwhile,most of the intercellular amino acid content of the cells after Me AIB co-culturing was significantly lower(P<0.05).Furthermore,the m RNA expression levels of system L amino acid transporter 1(LAT1),silent information regulator 1,and peroxisome proliferator-activated receptor-gamma co-activator 1 alpha,as well as the protein expression levels of amino acid transporters LAT1 and vacuolar protein sorting 34,were all down-regulated.The phosphorylated protein expression levels of mammalian target of rapamycin(m TOR),regulatory-associated protein of m TOR,4 E binding protein 1,and ribosomal protein S6 kinase 1 after Me AIB treatment were also significantly down-regulated(P<0.05),which could contribute to the importance of SNAT2 in amino acid transportation and skeletal muscle cell sensing.In conclusion,SNAT2 suppression inhibited C2 C12 cell growth and differentiation,as well as the availability of free amino acids.Although the m TOR complex 1 signaling pathway was found to be involved,its response to different nutrients requires further study.
