The Emerging View of Aging as a Reversible Epigenetic Process

Gerontology ◽  
2017 ◽  
Vol 63 (5) ◽  
pp. 426-431 ◽  
Author(s):  
Micaela López-León ◽  
Rodolfo G. Goya

The achievement of animal cloning and subsequent development of cell reprogramming technology are having a profound impact on our view of the mechanisms of aging in complex organisms. The experimental evidence showing that an adult somatic nucleus implanted into an enucleated oocyte can give rise to a whole new individual strongly suggests that the integrity of the genome of an adult nucleus is fully preserved. Here, we will review recent experimental evidence showing that pluripotency gene-based cell reprogramming can erase the epigenetic marks of aging and rejuvenate cells from old individuals reversing most signs of aging and that when induced pluripotent stem cells are differentiated back to the cell type of origin, the rejuvenated cells share many of the features of wild-type counterparts from young donors. This evidence supports the idea that progressive epigenetic dysregulation may be the key driver of organismal aging and challenges the conventional view of aging as an irreversible process. The model of aging as an epigenetic process provides an elegant explanation of a number of age-related processes difficult to explain by conventional theories of aging.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Wei ◽  
Daniel J. Gaffney ◽  
Patrick F. Chinnery

AbstractIndividual induced pluripotent stem cells (iPSCs) show considerable phenotypic heterogeneity, but the reasons for this are not fully understood. Comprehensively analysing the mitochondrial genome (mtDNA) in 146 iPSC and fibroblast lines from 151 donors, we show that most age-related fibroblast mtDNA mutations are lost during reprogramming. However, iPSC-specific mutations are seen in 76.6% (108/141) of iPSC lines at a mutation rate of 8.62 × 10−5/base pair. The mutations observed in iPSC lines affect a higher proportion of mtDNA molecules, favouring non-synonymous protein-coding and tRNA variants, including known disease-causing mutations. Analysing 11,538 single cells shows stable heteroplasmy in sub-clones derived from the original donor during differentiation, with mtDNA variants influencing the expression of key genes involved in mitochondrial metabolism and epidermal cell differentiation. Thus, the dynamic mtDNA landscape contributes to the heterogeneity of human iPSCs and should be considered when using reprogrammed cells experimentally or as a therapy.


2021 ◽  
Vol 22 (13) ◽  
pp. 6800
Author(s):  
Maria Hytti ◽  
Eveliina Korhonen ◽  
Heidi Hongisto ◽  
Kai Kaarniranta ◽  
Heli Skottman ◽  
...  

Inflammation is a key underlying factor of age-related macular degeneration (AMD) and inflammasome activation has been linked to disease development. Induced pluripotent stem-cell-derived retinal pigment epithelial cells (iPSC-RPE) are an attractive novel model system that can help to further elucidate disease pathways of this complex disease. Here, we analyzed the effect of dysfunctional protein clearance on inflammation and inflammasome activation in iPSC-RPE cells generated from a patient suffering from age-related macular degeneration (AMD) and an age-matched control. We primed iPSC-RPE cells with IL-1α and then inhibited both proteasomal degradation and autophagic clearance using MG-132 and bafilomycin A1, respectively, causing inflammasome activation. Subsequently, we determined cell viability, analyzed the expression levels of inflammasome-related genes using a PCR array, and measured the levels of pro-inflammatory cytokines IL-1β, IL-6, IL-8, and MCP-1 secreted into the medium. Cell treatments modified the expression of 48 inflammasome-related genes and increased the secretion of mature IL-1β, while reducing the levels of IL-6 and MCP-1. Interestingly, iPSC-RPE from an AMD donor secreted more IL-1β and expressed more Hsp90 prior to the inhibition of protein clearance, while MCP-1 and IL-6 were reduced at both protein and mRNA levels. Overall, our results suggest that cellular clearance mechanisms might already be dysfunctional, and the inflammasome activated, in cells with a disease origin.


Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 253 ◽  
Author(s):  
Lubos Danisovic ◽  
Martina Culenova ◽  
Maria Csobonyeiova

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder, caused by mutation of the DMD gene which encodes the protein dystrophin. This dystrophin defect leads to the progressive degeneration of skeletal and cardiac muscles. Currently, there is no effective therapy for this disorder. However, the technology of cell reprogramming, with subsequent controlled differentiation to skeletal muscle cells or cardiomyocytes, may provide a unique tool for the study, modeling, and treatment of Duchenne muscular dystrophy. In the present review, we describe current methods of induced pluripotent stem cell generation and discuss their implications for the study, modeling, and development of cell-based therapies for Duchenne muscular dystrophy.


Acta Naturae ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 92-97
Author(s):  
V. V. Sherstyuk ◽  
G. I. Davletshina ◽  
Y. V. Vyatkin ◽  
D. N. Shtokalo ◽  
V. V. Vlasov ◽  
...  

Reprogramming of somatic cells to a pluripotent state is a complex, multistage process that is regulated by many factors. Among these factors, non-coding RNAs and microRNAs (miRNAs) have been intensively studied in recent years. MiRNAs play an important role in many processes, particularly in cell reprogramming. In this study, we investigated the reprogramming of rat fibroblasts with a deleted locus encoding a cluster comprising 14 miRNAs (from miR-743a to miR-465). The deletion of this locus was demonstrated to decrease significantly the efficiency of the cell reprogramming. In addition, the cells produced by the reprogramming differed from rat embryonic and induced pluripotent stem cells, which was an indication that reprogramming in these cells had not been completed. We suggest that this miRNA cluster or some of its members are involved in regulating the reprogramming of rat cells to a pluripotent state.


Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1848
Author(s):  
Mirae Kim ◽  
Seon-Ung Hwang ◽  
Junchul David Yoon ◽  
Yeon Woo Jeong ◽  
Eunhye Kim ◽  
...  

Canine induced pluripotent stem cells (ciPSCs) can provide great potential for regenerative veterinary medicine. Several reports have described the generation of canine somatic cell-derived iPSCs; however, none have described the canine somatic cell reprogramming using a non-integrating and self-replicating RNA transfection method. The purpose of this study was to investigate the optimal strategy using this approach and characterize the transition stage of ciPSCs. In this study, fibroblasts obtained from a 13-year-old dog were reprogrammed using a non-integrating Venezuelan equine encephalitis (VEE) RNA virus replicon, which has four reprogramming factors (collectively referred to as T7-VEE-OKS-iG and comprised of hOct4, hKlf4, hSox2, and hGlis1) and co-transfected with the T7-VEE-OKS-iG RNA and B18R mRNA for 4 h. One day after the final transfection, the cells were selected with puromycin (0.5 µg/mL) until day 10. After about 25 days, putative ciPSC colonies were identified showing TRA-1-60 expression and alkaline phosphatase activity. To determine the optimal culture conditions, the basic fibroblast growth factor in the culture medium was replaced with a modified medium supplemented with murine leukemia inhibitory factor (mLIF) and two kinase inhibitors (2i), PD0325901(MEK1/2 inhibitor) and CHIR99021 (GSK3β inhibitor). The derived colonies showed resemblance to naïve iPSCs in their morphology (dome-shaped) and are dependent on mLIF and 2i condition to maintain an undifferentiated phenotype. The expression of endogenous pluripotency markers such as Oct4, Nanog, and Rex1 transcripts were confirmed, suggesting that induced ciPSCs were in the late intermediate stage of reprogramming. In conclusion, the non-integrating and self-replicating VEE RNA replicon system can potentially make a great contribution to the generation of clinically applicable ciPSCs, and the findings of this study suggest a new method to utilize the VEE RNA approach for canine somatic cell reprogramming.


Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2383
Author(s):  
Suet Theng Beh ◽  
Carlye Frisch ◽  
David A. Brafman ◽  
Jared Churko ◽  
Jessica E. Walker ◽  
...  

The Arizona Study of Aging and Neurodegenerative Disorders/Brain and Body Donation Program at Banner Sun Health Research Institute (BSHRI) is a longitudinal clinicopathological study with a current enrollment of more than 900 living subjects for aging and neurodegenerative disease research. Annual clinical assessments are done by cognitive and movement neurologists and neuropsychologists. Brain and body tissues are collected at a median postmortem interval of 3.0 h for neuropathological diagnosis and banking. Since 2018, the program has undertaken banking of scalp fibroblasts derived from neuropathologically characterized donors with Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative diseases. Here, we describe the procedure development and cell characteristics from 14 male and 15 female donors (mean ± SD of age: 83.6 ± 12.2). Fibroblasts from explant cultures were banked at passage 3. The results of mRNA analysis showed positive expression of fibroblast activation protein, vimentin, fibronectin, and THY1 cell surface antigen. We also demonstrated that the banked fibroblasts from a postmortem elderly donor were successfully reprogramed to human-induced pluripotent stem cells (hiPSCs). Taken together, we have demonstrated the successful establishment of a human autopsy-derived fibroblast banking program. The cryogenically preserved cells are available for request at the program website of the BSHRI.


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