scholarly journals Multifaceted deregulation of gene expression and protein synthesis with age

2020 ◽  
Vol 117 (27) ◽  
pp. 15581-15590 ◽  
Author(s):  
Aleksandra S. Anisimova ◽  
Mark B. Meerson ◽  
Maxim V. Gerashchenko ◽  
Ivan V. Kulakovskiy ◽  
Sergey E. Dmitriev ◽  
...  

Protein synthesis represents a major metabolic activity of the cell. However, how it is affected by aging and how this in turn impacts cell function remains largely unexplored. To address this question, herein we characterized age-related changes in both the transcriptome and translatome of mouse tissues over the entire life span. We showed that the transcriptome changes govern those in the translatome and are associated with altered expression of genes involved in inflammation, extracellular matrix, and lipid metabolism. We also identified genes that may serve as candidate biomarkers of aging. At the translational level, we uncovered sustained down-regulation of a set of 5′-terminal oligopyrimidine (5′-TOP) transcripts encoding protein synthesis and ribosome biogenesis machinery and regulated by the mTOR pathway. For many of them, ribosome occupancy dropped twofold or even more. Moreover, with age, ribosome coverage gradually decreased in the vicinity of start codons and increased near stop codons, revealing complex age-related changes in the translation process. Taken together, our results reveal systematic and multidimensional deregulation of protein synthesis, showing how this major cellular process declines with age.

Author(s):  
Aleksandra S. Anisimova ◽  
Mark B. Meerson ◽  
Maxim V. Gerashchenko ◽  
Ivan V. Kulakovskiy ◽  
Sergey E. Dmitriev ◽  
...  

Protein synthesis represents a major metabolic activity of the cell. However, how it is affected by aging and how this in turn impacts cell function remains largely unexplored. To address this question, herein we characterized age-related changes in both the transcriptome and translatome of mouse tissues over the entire lifespan. Expression of the majority of differentially expressed genes followed a U-shaped curve with the turning point around 3-months-old. We showed that transcriptome changes govern changes in the translatome and are associated with altered expression of genes involved in inflammation, extracellular matrix and lipid metabolism. We also identified genes that may serve as candidate biomarkers of aging. At the translational level, we uncovered sustained down-regulation of a set of 5’ terminal oligopyrimidine (5’TOP) transcripts encoding protein synthesis and ribosome biogenesis machinery and regulated by the mTOR pathway. For many of them, ribosome occupancy dropped 3-fold or even more. Moreover, with age, ribosome coverage gradually decreased in the vicinity of start codons and increased near stop codons, revealing complex age-related changes in the translation process. Taken together, our results reveal systematic and multi-dimensional deregulation in protein synthesis, showing how this major cellular process declines with age.


Genetika ◽  
2014 ◽  
Vol 46 (1) ◽  
pp. 287-301 ◽  
Author(s):  
Biljana Bufan ◽  
Jasmina Djikic ◽  
Mirjana Nacka-Aleksic ◽  
Zorica Stojic-Vukanic ◽  
Mirjana Dimitrijevic ◽  
...  

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis, a prototype of Th1/Th17-mediated organ-specific autoimmune disease. In the rat, susceptibility to development of these diseases is shown to be strain-and age-dependent. In adult rats of distinct strains, it correlates with splenic dendritic cell (DC) subset composition, which also exhibit age-related changes. The aim of this study was to examine influence of aging on: i) Albino Oxford (relatively resistant to EAE) and Dark Agouti (susceptible to EAE) rat development of EAE and ii) their splenic conventional (OX62+) DC population in respect to its subset composition and expression of mRNAs for proinflammatory and immunosuppressive cytokines. We used 3month-old (young) and 26-month-old (aged) rats of AO and DA strain. The rats were immunized for EAE with rat spinal cord homogenate in complete Freund?s adjuvant and clinical course of the disease was followed. Fresh OX62+DCs were examined for the expression of CD4 (using flow cytometry) and genes encoding cytokines influencing DC activation/maturation (TNF-? and IL-6) using RT-PCR. Additionally, in vitro lipopolysaccharide (LPS) activated/matured DCs were examined for the expression of genes encoding cytokines controlling Th1/Th17 cell polarization using RT-PCR. With aging, AO rats became more susceptible, whereas DA rats largely lose their susceptibility to the induction of EAE. In AO rats aging shifted CD4+:CD4DC ratio towards CD4-cells, producing large amount of proinflammatory cytokines, whereas in DA rats CD4+:CD4-DC ratio remained stable with aging. In fresh DCs from rats of both the strains the expression of TNF-? mRNA increased with aging, whereas that of IL-6 mRNA decreased and increased in DCs from AO and DA rats, respectively. Following in vitro LPS stimulation OX62+ DCs from aged AO rats up-regulated the expression of mRNA for IL-23p19 (specific subunit of IL-23; crucial for sustained IL-17 production) and IL-1? (positive IL-17 regulator), whereas down-regulated the expression of IL-10 (negative IL-17 regulator) when compared with young strain-matched rats. In DA rats aging incresed IL-23p19 mRNA expression in LPS-stimulated DCs, whereas exerted the opposing effects on the expression of mRNAs for IL-10 and IL-1? compared to AO rats. Irrespective of the rat strain, aging did not influence mRNA expression for IL-12p35 (driving Th1 polarization) in DCs. Overall, results suggest role of changes in the expression of genes encoding proinflammatory and immunosuppressive cytokines in development of age-related alterations in rat susceptibility to EAE induction.


2021 ◽  
Vol 15 ◽  
Author(s):  
Jenny Lutshumba ◽  
Barbara S. Nikolajczyk ◽  
Adam D. Bachstetter

Neuroinflammation and the tissue-resident innate immune cells, the microglia, respond and contribute to neurodegenerative pathology. Although microglia have been the focus of work linking neuroinflammation and associated dementias like Alzheimer’s Disease, the inflammatory milieu of brain is a conglomerate of cross-talk amongst microglia, systemic immune cells and soluble mediators like cytokines. Age-related changes in the inflammatory profile at the levels of both the brain and periphery are largely orchestrated by immune system cells. Strong evidence indicates that both innate and adaptive immune cells, the latter including T cells and B cells, contribute to chronic neuroinflammation and thus dementia. Neurodegenerative hallmarks coupled with more traditional immune system stimuli like infection or injury likely combine to trigger and maintain persistent microglial and thus brain inflammation. This review summarizes age-related changes in immune cell function, with special emphasis on lymphocytes as a source of inflammation, and discusses how such changes may potentiate both systemic and central nervous system inflammation to culminate in dementia. We recap the understudied area of AD-associated changes in systemic lymphocytes in greater detail to provide a unifying perspective of inflammation-fueled dementia, with an eye toward evidence of two-way communication between the brain parenchyma and blood immune cells. We focused our review on human subjects studies, adding key data from animal models as relevant.


Gerontology ◽  
2015 ◽  
Vol 62 (3) ◽  
pp. 304-310 ◽  
Author(s):  
Agata Wronska ◽  
Aleksandra Lawniczak ◽  
Piotr M. Wierzbicki ◽  
Zbigniew Kmiec

Background: Sirtuins (SIRT1-7) have been implicated to mediate the beneficial effects of calorie restriction for healthy aging. While the physiological functions of SIRT7 are still poorly understood, SIRT7 has recently been shown to affect ribosome biogenesis, mitochondrial gene expression, and hepatic lipid metabolism. Objective: To analyze the effects of age and short-term calorie restriction (SCR) and subsequent refeeding on SIRT7 expression in key metabolic tissues. Methods: Four- and 24-month-old male Wistar rats were subjected to 40% SCR for 30 days, followed by ad libitum feeding for 2 or 4 days. Liver, white adipose tissue (WAT), heart and skeletal muscle samples were analyzed by real-time PCR and Western blotting for SIRT7 mRNA and protein expression, respectively. Results: Aging had diverse effects on SIRT7 levels in lipogenic tissues: both the mRNA and protein levels increased in the retroperitoneal depot (rWAT), did not change in the epididymal depot (eWAT), and decreased in the subcutaneous depot (sWAT) and the liver of old as compared to young animals. In the heart, extensor digitorum longus muscle (EDL) and soleus muscle (SOL), Sirt7 gene but not protein expression was lower in old than in young control rats. SCR did not affect SIRT7 expression in WAT and the liver in both age groups. In the heart of young animals, SCR did not affect SIRT7 mRNA or protein level. In EDL, SIRT7 protein but not mRNA levels decreased after SCR and remained reduced upon refeeding. In SOL, both SIRT7 mRNA and protein expression were inhibited by refeeding. In old rats, cardiac Sirt7 expression increased after SCR and refeeding. In old rats' EDL and SOL muscles, SIRT7 protein expression was inhibited by refeeding. Conclusion: Age-related changes of SIRT7 gene expression in key organs of energy homeostasis are tissue dependent.


1978 ◽  
Vol 13 (3-4) ◽  
pp. 197-205 ◽  
Author(s):  
Daniel S.H. Liu ◽  
Rick Ekstrom ◽  
John W. Spicer ◽  
Arlan Richardson

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