Spiny mice (Acomys) exhibit attenuated hallmarks of aging and rapid cell turnover after UV exposure in the skin epidermis

The Information Theory of Aging

Information storage and retrieval is essential for all life. In biology, information is primarily stored in two distinct ways: the genome, comprising nucleic acids, acts as a foundational blueprint and the epigenome, consisting of chemical modifications to DNA and histone proteins, regulates gene expression patterns and endows cells with specific identities and functions. Unlike the stable, digital nature of genetic information, epigenetic information is stored in a digital-analog format, susceptible to alterations induced by diverse environmental signals and cellular damage. The Information Theory of Aging (ITOA) states that the aging process is driven by the progressive loss of youthful epigenetic information, the retrieval of which via epigenetic reprogramming can improve the function of damaged and aged tissues by catalyzing age reversal.

Comparative analysis of Acomys cahirinus and Mus musculus responses to genotoxicity, oxidative stress, and inflammation

The Egyptian spiny mouse, Acomys cahirinus, is a recently described model organism for regeneration studies. It has surprising powers of regeneration with relatively fast repairing mechanisms and reduced inflammation form compared to other mammals. Although several studies have documented the exceptional capabilities of Acomys to regenerate different tissues after injury, its response to different cellular and genetic stresses is not yet investigated. Therefore, the current study aimed to investigate Acomys abilities to resist genotoxicity, oxidative stress and inflammation induced by acute and subacute treatments with lead acetate. Responses of Acomys were compared with those of the lab mouse (Mus musculus), which displays signatures of the "typical" mammalian response to various stressors. Cellular and genetic stresses were induced by using acute and subacute doses of Lead acetate (400 mg/kg and 50 mg/kg for 5 days, respectively). The assessment of genotoxicity was carried out by using comet assay, while oxidative stress was evaluated by measuring the biomarkers; MDA, GSH and antioxidant enzymes CAT and SOD. Moreover, inflammation was assessed by analyzing the expression of some inflammatory-regeneration-related genes: CXCL1, IL1-β, and Notch 2 and immunohistochemical staining of TNF-α protein in brain tissue, in addition to histopathological examination of brain, liver, and kidneys. The obtained results revealed a unique resistance potency of Acomys to genotoxicity, oxidative stress, and inflammation in certain tissues in comparison to Mus. Altogether, the results revealed an adaptive and protective response to cellular and genetic stresses in Acomys.

Tumor suppressors inhibit reprogramming of African spiny mouse ( Acomys) fibroblasts to induced pluripotent stem cells

Background: The African spiny mouse ( Acomys) is an emerging mammalian model for scar-free regeneration, and further study of Acomys could advance the field of regenerative medicine. Isolation of pluripotent stem cells from Acomys would allow for development of transgenic or chimeric animals and in vitro study of regeneration; however, the reproductive biology of Acomys is not well characterized, complicating efforts to derive embryonic stem cells. Thus, we sought to generate Acomys induced pluripotent stem cells (iPSCs) by reprogramming somatic cells back to pluripotency. Methods: To generate Acomys iPSCs, we attempted to adapt established protocols developed in Mus. We utilized a PiggyBac transposon system to genetically modify Acomys fibroblasts to overexpress the Yamanaka reprogramming factors as well as mOrange fluorescent protein under the control of a doxycycline-inducible TetON operon system. Results: Reprogramming factor overexpression caused Acomys fibroblasts to undergo apoptosis or senescence. When SV40 Large T antigen (SV40 LT) was added to the reprogramming cocktail, Acomys cells were able to dedifferentiate into pre-iPSCs. Although use of 2iL culture conditions induced formation of colonies resembling Mus PSCs, these Acomys iPS-like cells lacked pluripotency marker expression and failed to form embryoid bodies. An EOS-GiP system was unsuccessful in selecting for bona fide Acomys iPSCs; however, inclusion of Nanog in the reprogramming cocktail along with 5-azacytidine in the culture medium allowed for generation of Acomys iPSC-like cells with increased expression of several naïve pluripotency markers. Conclusions: There are significant roadblocks to reprogramming Acomys cells, necessitating future studies to determine Acomys-specific reprogramming factor and/or culture condition requirements. The requirement for SV40 LT during Acomys dedifferentiation may suggest that tumor suppressor pathways play an important role in Acomys regeneration and that Acomys may possess unreported cancer resistance.