Accurate estimates of parameters and demographic rates of wildlife populations are crucial to management and conservation. One parameter of interest is age because it influences multiple demographic rates and behaviors including reproduction, dispersal, migration, and disease transmission. There are a number of methods used to estimate ages of wildlife. One of the most common methods used for mammals is evaluation of patterns in dental eruption and tooth wear. In the first chapter, we evaluate the accuracy associated with estimates of age from dental eruption and patterns of tooth wear for mule deer (Odocoileus hemionus). In the second chapter, we use age estimates validated within the first chapter to explore how age and other maternal factors may influence number of offspring born per litter in mule deer. We further test relative support for two common hypotheses--terminal investment and reproductive restraint--regarding the relationship between age and reproductive investment in this species. Our results will inform conservation, management, and research efforts associated with mule deer.

Abstract (Summary) Wood turtles ( Glyptemys insculpta ) are of conservation interest rangewide. Anecdotal accounts demonstrate that some populations have been decimated since 1850, and recent studies demonstrate that declines are still underway. From 2004-2008 I investigated the ecology of wood turtles in Massachusetts and New Hampshire. I obtained between one and five years of annual home range data for 150 turtles, and evaluated population structure at 31 sites in five major watersheds. Seasonal floods displaced 7% of wood turtles annually in one watershed, and accounted for elevated mortality. Twelve wood turtles were displaced < 16.8 km, and two were displaced over a 65-foot dam. Several turtles overwintered at their displacement site and two returned successfully, indicating that floods are a mechanism of population connectivity. Several homing turtles ended up in new areas. Turtles occupied stream segments with gradient < 1%, lower than generally available. Agricultural machinery accounted for most observed mortality, followed by automobiles and mammals. Female turtles exhibit smaller home ranges in agricultural areas. Older turtles move farther from the river than do young turtles, possibly reflecting their familiarity with a former landscape. Population density ranged from 0-40.4 turtles/river-kilometer. The highest densities occur in central New Hampshire and lower densities occur in the Housatonic watershed. Population density is negatively correlated with agriculture at both riparian and watershed scales, and responds unimodally to forest cover. Wood turtle populations in western Massachusetts are declining by 6.6-11.2% annually. I estimated ages of turtles by assessing shell-wear rates from photographs. Wood turtles regularly achieve ages over 80 years, and like related species, do not exhibit clear signs of senescence. Old wood turtles are reproductively dominant, and their survival rates are twice as high as young turtles. Carapace scutes appear to require 80 years to become worn. Population modeling indicates that wood turtle populations are declining in New England due to anthropogenic and natural factors. Conservation efforts must address the effects of agriculture on adult survival. Climate change may negatively affect northeastern wood turtles through increased flooding. Populations in mountainous areas may be likely candidates for conservation because they don't occupy prime agricultural land, but may be more susceptible to floods.

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Despite the advent of stents, intimal hyperplasia subsequent to vascular interventional procedures remains a major obstacle. Vascular smooth muscle cells (VSMC) play a critical role in the pathogenesis of intimal hyperplasia; therefore, regulation of VSMC gene expression is a logical intervention point. FXR1 is a muscle-enhanced RNA binding protein and its expression is increased in injured arteries. We have shown that modulation of FXR1 levels affects stability and abundance of inflammatory transcripts in VSMC, suggesting that FXR1 is a negative regulator of inflammation. RNA-sequencing analysis in FXR1-depleted human VSMC (hVSMC) identified a number of transcripts with decreased abundance, the overwhelming majority of which were associated with proliferation and cell division. This drives our hypothesis that FXR1 is involved in mitigating vascular disease by regulating inflammatory and proliferative mRNA in VSMC. The mRNA abundance and stability of a number of these transcripts was decreased in FXR1 depleted hVSMC, and RIP-sequencing demonstrated that FXR1 interacts with transcripts involved in cell cycle control, and stability of these transcripts is decreased with FXR1 depletion. FXR1-depleted cells showed decreased proliferation (p<0.05), however, an increase in β-galactosidase (p<0.05) and γH2AX (p<0.01), indicative of senescence was noted. Senescent cells exhibit a senescence associated secretory phenotype (SASP) with characteristic gene expression leading to increased inflammation in the tissue microenvironment. HVSMC depleted of FXR1 had increased transcripts abundance of many SASP genes, as well as an increase of both mRNA and protein expression of canonical senescence markers p53 and p21. We developed a novel SMC-specific conditional knockout mouse (FXR1SMC/SMC) to further study these results in a more translational context. In a carotid artery ligation model of intimal hyperplasia, FXR1SMC/SMC mice have significantly reduced neointima formation (p<0.001) post-ligation compared to controls. qPCR analysis from FXR1 conditional knockout mouse VSMC (mVSMC) show increased transcripts associated with senescence (p21, p16, p53) as well as increased SASP-associated mRNA, a decrease in proliferation, and an increase in β-galactosidase staining. Our results are the first to suggest that in addition to destabilization of inflammatory transcripts, FXR1 may stabilize cell cycle related genes in VSMC, and absence of FXR1 leads to induction of a senescent phenotype, an increase in SASP genes, and reduction of intimal hyperplasia. / Organ Systems & Translational Medicine

Background: Ageing is associated with age-related disease and it has been divided into 12 hallmarks and cellular senescence is one of them. Cellular senescence increases with age and has different pathological inducing aspects in the tissue. Hyperbaric oxygen therapy is used in the clinic to treat different pathological conditions and has emerged as a possible intervention for the reduction of senescent cells. Reducing senescent cells could be a way to reduce the effects of ageing and therefore possibly in the future treat age-related diseases. Aim: This systematic literature review aims to investigate articles researching the effect of HBO exposure on senescent cells and the properties of senescent cells. Methods: PubMed database was used in this systematic literature review. Exclusion and inclusion criteria were specified using the PECO format. A search plan was created using both MeSH words and free text words. An article search was performed twice on 11 th September 2023 and 20 th November 2023. The exclusion and inclusion criteria were used to filter the search results and for the full-text review. Result: 6 articles in total were included in this study. 2 of those included articles were conducted on humans while the rest were conducted on animals or animal cells. Two studies showed that HBOT decreases the number of senescent cells, one study showed that the senescent cell markers and SASP were decreased post-HBOT, two studies showed that the properties of senescent cells were decreased post-HBOT while one study showed the contrary with an increased senescent cell properties. Conclusion: The result of this systematic literature review suggests that there is an association between HBOT and a decrease in senescent cells or its properties. More research is needed though to better understand the relationship between HBOT and the effect it imposes on senescent cells.

Aging of the brain is the leading risk factor for neurodegenerative diseases and brain cancers and has deleterious effects on brain functions. It follows that attempts to reverse the aging process may be therapeutically valuable. Neural stem cells (NSC) have been shown to play a critical role in maintaining brain functions, and their number is severely decreased with age. The development of senescence-like characteristics and declining functions in NSCs have been proposed to be responsible for brain aging and tumorigenesis. MS-818 is a pyrrolopyrimidine that has been shown to increase the NSC population and reverse the decline of behavioral function in aged rodent models. While MS-818 has demonstrated such benefits, the mechanism by which it affects particular pathways of biological age in NSCs is not yet known. Understanding how MS-818 relates to the molecular mechanisms underlying cellular aging may help accelerate the development of anti-aging therapies for neurodegenerative diseases and cancer. This study attempts to elucidate the mechanism of action of MS-818 on NSCs using an in vitro accelerated-aging model produced by Hydroxyurea (HU) treatment. Our analysis of NSC population size post-MS-818 exposure supports the idea that MS-818 treatment can increase NSC proliferation. qPCR analysis of aging-related genes revealed HU treatment produced a trend of increased p16 and Il-6 and decreased Lamin B1 relative expression, supporting the notion that HU treatment can induce senescence in NSCs. MS-818 treatment alone also produced notable trends for targets including BRCA1. In addition, MS-818 treatment post-HU exposure appeared to influence the relative expression of targets, including PGC1a and Lamin B1. Such MS-818 treatment produced similarly noteworthy trends for the expression of genes including PGC1a, Lamin B1, BRCA1, RPTOR, and Il-6, whether in media containing 2.5% or 7.5% serum. These results indicate that MS-818 may have influenced some aging-related pathways.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23744号 / 理博第4834号 / 新制||理||1691(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 工藤 洋, 准教授 本庄 三恵, 教授 松下 智直 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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