Macroautophagy, hereafter referred to as autophagy, is a catabolic process involving the degradation of cellular proteins and structures sequestered into a vesicle known as an autophagosome. The initiation of autophagy involves the conversion of a protein microtubule-associated proteins 1A/1B light chain 3B (LC3) from form I to form II allowing interaction with the formation of the autophagosome. Using an LC3-II/I ratio, relative initiation of autophagy can be estimated since higher relative amounts of LC3-II suggests a higher conversion rate of LC3-I to LC3-II, therefore suggesting autophagosomes are being formed at a higher rate. Autophagy’s selectivity, or its ability to degrade specific targets, is dependent on the degradation of ubiquitinated proteins and a protein adaptors, the latter forming a physical bridge between the ubiquitin-tagged cargo and LC3-II present on the forming autophagosome. Without these protein adaptors, autophagy has no selectivity and portions of the cytosol that happen to be near the autophagosome formation site are the only cellular components captured and degraded. Because the entire contents of the autophagosome are degraded following lysosome fusion, the selectivity can be assessed by determining the levels of protein adaptor and ubiquitinated proteins. Autophagy is constitutively active but is strongly stimulated under nutrient deprivation, such as fasting. Impairments of autophagy have been implicated in contractile and/or metabolic deficiencies in muscle diseases, obesity, diabetes, and aging; however, regulation of skeletal muscle autophagy is poorly understood at the molecular level. Here, we examined the role of the two partially homologous unc-51 like autophagy activating kinases 1 and 2 (ULK1 and ULK2) in modulating autophagy and myofiber atrophy during fasting via a microRNA-specific knockdown of these proteins in mouse skeletal muscle and using a non-specific microRNA in the contralateral muscle to allow comparisons of ULK effects within the same animal. Our results revealed that deficiency of ULK1 caused LC3-I to accumulate in fasted muscle without changes in Lc3b mRNA, indicating an impairment in the step of LC3-I conversion into LC3-II (an essential step in autophagy initiation). Similar trends were observed with other LC3-like proteins (GABL1 and GABL2) suggesting a specific role for ULK1 in regulating autophagy initiation. Deficiency of ULK2 did not affect LC3 or LC3-like proteins suggesting that ULK2 does not regulate autophagy initiation. However, it led to accumulation of ubiquitinated proteins, and the autophagy adaptors p62 and NBR-1, under both basal and fasting conditions. Since autophagy adaptors bind to and are degraded together with ubiquitinated proteins, these findings are consistent with impaired involvement of adaptors and consequent deficient cargo recognition by autophagy. Of note, deficient expression of either ULK1, ULK2, or both ULK1 & ULK2 did not attenuate myofiber atrophy during fasting. Altogether, these results uncover fundamental divergent roles for ULK1 and ULK2 in modulating autophagy and its selectivity in muscle. Current and future studies in our laboratory will further expand the molecular signature of autophagy activation and selectivity in muscle in order to identify novel targets for therapy in conditions associated with autophagy deficiency.

This dissertation is a critical examination of the relationship between sleep problems and/or disorders, particularly Obstructive Sleep Apnea (OSA) and Alzheimer Disease (AD). First, I conducted an exhaustive systematic review of existing literature, and identified gaps in research that led to specific research aims. For the first aim, I conducted the first ever-published meta-analysis examining sleep, cognitive decline and AD, providing an aggregate effect of sleep on AD. Second, focusing on OSA, I conducted a study examining OSA’s effect on longitudinal changes on AD biomarkers in cognitive normal, MCI and AD subjects, using data from the Alzheimer Disease Neuroimaging Initiative (ADNI). Lastly, I conducted a review, integrating over 3 decades of research examining OSA and cognition; OSA and subsequent cognitive decline; and OSA and AD; with particular focus in appreciating the heterogeneity of OSA and its outcomes in distinct age groups. Results and implications from my research indicate that ample evidence exists linking sleep impairments and circadian regulating mechanisms directly to clinical symptoms in AD. Sleep problems and/or disorders increases your risk of cognitive decline and AD. OSA is associated with increased AD biomarker burden over time, and effects longitudinal changes in these biomarkers, such that OSA subjects progress faster than non-OSA subjects do. OSA may be age-dependent in older adults (60 – 70 years old) and the elderly (70 years and above) and is associated with neurodegenerative diseases particularly, cognitive decline and AD. Intermittent hypoxia and sleep fragmentation are two main processes by which OSA induces neurodegenerative changes. Therefore, clinical interventions aimed at OSA, such as treatment with CPAP or dental appliances, in cognitive normal and MCI patients, could possibly slow the progression of cognitive impairment to AD.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

The domestic dog, Canis lupus familiaris, has emerged as a model system for the study of human hereditary diseases. Of the approximately 450 hereditary diseases described in the dog, half have clinical presentations that are quite similar to specific human diseases. Understanding the genetic bases of canine hereditary diseases will not only complement comparative genetics studies but also facilitate selective breeding practices to reduce incidences in the dog. Whole genome screens have great potential to identify the marker(s) that segregate with canine hereditary diseases for which no reasonable candidate genes exist. The Minimal Screening Set-1 (MSS-1) was the first set of microsatellite markers described for linkage analysis in the dog and was, until recently, the best tool for genome screens. The MSS-2 is the most recently described screening set and offers increased density and more polymorphic markers. The first objective of this work was to develop tools to streamline genomic analyses in the study of canine hereditary diseases. This was achieved through the development of 1) multiplexing strategies for the MSS-1, 2) a multiplex of microsatellite markers for use in canine forensics and parentage assays and 3) chromosome-specific multiplex panels for the MSS-2. Multiplexing is the simultaneous amplification and analysis of markers and significantly reduces the expense and time required to collect genotype information. Pancreatic acinar atrophy (PAA) is a disease characterized by the degeneration of acinar cells of the exocrine pancreas and is the most important cause of exocrine pancreatic insufficiency (EPI) in the German Shepherd Dog (GSD). Although the prognosis for dogs having EPI is typically good with treatment, many dogs are euthanized because the owners are unable to afford the expensive enzyme supplements. The second objective of this work was to determine the mode of transmission of EPI in the GSD and conduct a whole genome screen for linkage. Two extended families of GSDs having PAA were assembled and used to determine the pattern of transmission. The results of this indicate that PAA is an autosomal recessive disease. The multiplexed MSS-1 was used to conduct an initial whole genome screen, although no markers were suggestive of linkage.

No description available.

No description available.

名古屋大学博士学位論文 学位の種類 : 博士(医学)(論文) 学位授与年月日:平成5年1月28日 平山正昭氏の博士論文として提出された

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 19, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Christian Lorson and Dr. Michael Garcia. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri--Columbia, 2002. / "December 2002." Typescript. Vita. Includes bibliographical references (leaves 143-155). Also available on the Internet.

published_or_final_version / Paediatrics / Master / Master of Philosophy