The role of autophagy machinery in osteoclast disease pathogenesis

Osteoclast disease, such as Paget’s disease of the bone and osteoporosis, are pathological conditions of excessive bone resportion caused by disproportionate generation or over-activation of osteoclasts. They represent some of the most common chronic diseases that result in morbidity and disability in the elderly population with an estimation of more than 60 million people in the US currently affected with osteoclast diseases. My dissertation research focuses on studying the role of autophagy machinery in osteoclast differentiation and osteoclast disease pathogenesis. In the second chapter, we investigate the role autophagy receptor Optineurin (OPTN) in the pathogenesis of Paget’s disease of the bone (PDB). We identify that OPTN acts as an intrinsic negative modulator for osteoclast development, as it restrains osteoclast differentiation in vitro and protects against the development of PDB in vivo. While the absence of OPTN results in a defective type I interferon responses in osteoclasts, exogenous supplementations of recombinant IFN completely reverse the hyperactivity observed in OPTN deficient osteoclasts. Therefore, we propose that IFN could serve a novel pharmacotherapy for PDB. In the third chapter, we investigate the role of autophagy machinery in osteoclast differentiation. We reveal that certain upstream autophagy core proteins, such Beclin-1, VPS34, ATG14 and FIP200 are required for osteoclast development, which seems to be dispensable of autophagic flux. Moreover, we uncovered the noncanonical roles of autophagy protein Beclin-1 in osteoclast differentiation – nuclear Beclin-1 protects against DNA damages and cell death to maintain sufficient noncanonical NF-kB responses during osteoclastogenesis. Since mice with myeloid restricted Becn1 deficiency exhibit insignificant age-related bone loss, Beclin1 may be a novel therapeutic target for osteoporosis. Taken together, my research adds knowledge to our current understanding of osteoclast development - the entire autophagy pathway is instrumental for osteoclast differentiation, through different components exert different control over the differentiation process. Targeting the autophagy and its effector pathways may be a novel anti-resorptive regimen for patients with osteoclast disease, and may potential benefit them in a multifaceted way.Doctor of Philosoph

An analysis of data obtained from show, non-show guinea pigs, and their offspring

Typescript, etc.Digitized by Kansas State University Librarie

THE ROLE OF NONCANONICAL AUTOPHAGY IN PERIODONTAL DISEASE PATHOGENESIS

Periodontal disease is a multifactorial disease that is associated with local infection and chronic inflammation in the tooth supporting tissues. In addition to the local etiologic factor, oral biofilm, host susceptibility also contributes to the disease pathogenesis and severity. Susceptible individuals may present with exaggerated inflammatory reactions in the periodontium, leading to alveolar bone resorption and eventually to loss of teeth. My dissertation research focuses on investigating the molecular mechanisms that underlie host susceptibility to periodontal disease.Originated from the Greek for “self-eating”, autophagy is a lysosome-mediated catabolic system that facilities the digestion of intracellular components to generate nutrients, which substantiate cell survival in the adverse environment. Emerging evidence has indicated that autophagy proteins can function beyond bulk degradation called non-canonical autophagy, which could regulate inflammation both in vivo and in vitro. Recent genome-wide association studies (GWAS) have identified genetic variations in multiple non-canonical autophagy genes that may be linked to periodontal disease. However, the role of non-canonical autophagy in periodontal disease pathogenesis remains unknown.In Chapter 1, we introduce the background of non-canonical autophagy (LC3-associated phagocytosis, LAP) and periodontal disease. In Chapter 2, we investigate the role of Rubicon, a key LAP protein in the pathogenesis of periodontal disease. Our results demonstrate that LAP could be activated by different periodontal pathogens in vitro. The absence of Rubicon results in accelerated periodontal disease progression and bone loss in vivo, suggesting that LAP may have a protective role in periodontal inflammation. Intrinsically, young Rubicon deficient mice exhibited normal skeletal phenotype and this deficiency does not interfere with osteoclast differentiation. In the last chapter, we discuss the significance of our findings and future research directions.Taken together, my research results add knowledge to our current understanding of the etiologies of periodontal diseases –non-canonical autophagy may be involved in the pathogenesis of periodontal disease, and the alterations of its function might contribute to periodontal disease susceptibility and severity.Master of Scienc

Telecom InP/InGaAs nanolaser array directly grown on (001) silicon-on-insulator

A compact, efficient, and monolithically grown III–V laser source provides an attractive alternative to bonding off-chip lasers for Si photonics research. Although recent demonstrations of microlasers on (001) Si wafers using thick metamorphic buffers are encouraging, scaling down the laser footprint to nanoscale and operating the nanolasers at telecom wavelengths remain significant challenges. Here, we report a monolithically integrated in-plane InP/InGaAs nanolaser array on (001) silicon-on-insulator (SOI) platforms with emission wavelengths covering the entire C band (1.55 μm). Multiple InGaAs quantum wells are embedded in high-quality InP nanoridges by selective-area growth on patterned (001) SOI. Combined with air-cladded InP/Si optical cavities, room-temperature operation at multiple telecom bands is obtained by defining different cavity lengths with lithography. The demonstration of telecom-wavelength monolithic nanolasers on (001) SOI platforms presents an important step towards fully integrated Si photonics circuits

Genome sequence and genetic linkage analysis of Shiitake mushroom _Lentinula edodes_

_Lentinula edodes_ (Shiitake/Xianggu) is an important cultivated mushroom. Understanding the genomics and functional genomics of _L. edodes_ allows us to improve its cultivation and quality. Genome sequence is a key to develop molecular genetic markers for breeding and genetic manipulation. We sequenced the genome of _L. edodes_ monokaryon L54A using Roche 454 and ABI SOLiD genome sequencing. Sequencing reads of about 1400Mb were de novo assembled into a 40.2 Mb genome sequence. We compiled the genome sequence into a searchable database with which we have been annotating the genes and analyzing the metabolic pathways. In addition, we have been using many molecular techniques to analyze genes differentially expressed during development. Gene ortholog groups of _L. edodes_ genome sequence compared across genomes of several fungi including mushrooms identified gene families unique to mushroom-forming fungi. We used a mapping population of haploid basidiospores of dikaryon L54 for genetic linkage analysis. High-quality variations such as single nucleotide polymorphisms, insertions, and deletions of the mapping population formed a high-density genetic linkage map. We compared the linkage map to the _L. edodes_ L54A genome sequence and located selected quantitative trait loci. The Shiitake community will benefit from these resources for genetic studies and breeding.
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Apathy and suicide-related ideation 3 months after stroke: a cross-sectional study

Background: Both apathy and suicide are common in poststroke patients. However, the association between poststroke apathy and suicide-related ideation (SI) in Chinese stroke patients is not clear and poorly understood. The aim of this study was to examine the association between apathy and SI in stroke. Methods: A cross-sectional study was conducted to investigate the association in 518 stroke survivors from Acute Stroke Unit of the Prince of Wales Hospital in Hong Kong. Geriatric Mental State Examination-Version A (GMS) and Neuropsychiatric Inventory-apathy subscale (NPI-apathy) were employed to assess poststroke SI and apathy, respectively. Patients’ clinical characteristics were obtained with the following scales: the National Institutes of Health Stroke Scale (NIHSS), the Mini-Mental State Examination (MMSE), and the Geriatric Depression Scale (GDS). Results: Thirty-two (6.2%) stroke survivors reported SI. The SI group had a significantly higher frequency of NPI-apathy than the non-SI group (31.2% vs 5.3%, p \u3c 0.001). The SI group also had higher GDS scores (10.47 ± 3.17 vs 4.24 ± 3.71, p \u3c 0.001). Regression analysis revealed that NPI-apathy (OR 2.955, 95% CI 1.142-7.647, p = 0.025) was a significant predictor of SI. The GDS score also predicted SI (OR 1.436, 95% CI 1.284-1.606, p \u3c 0.001). Conclusions: The current findings show that poststroke apathy is an independent predictor of SI 3 months after stroke. Early screening for and intervention targeting apathy through medication and psychological treatments may be necessary to improve stroke patients’ apathy and reduce SI

Senescence: novel insight into DLX3 mutations leading to enhanced bone formation in Tricho-Dento-Osseous syndrome

The homeodomain transcription factor distal-less homeobox 3 gene (DLX3) is required for hair, tooth and skeletal development. DLX3 mutations have been found to be responsible for Tricho-Dento-Osseous (TDO) syndrome, characterized by kinky hair, thin-pitted enamel and increased bone density. Here we show that the DLX3 mutation (c.533 A>G; Q178R) attenuates osteogenic potential and senescence of bone mesenchymal stem cells (BMSCs) isolated from a TDO patient, providing a molecular explanation for abnormal increased bone density. Both DLX3 mutations (c.533 A>G and c.571_574delGGGG) delayed cellular senescence when they were introduced into pre-osteoblastic cells MC3T3-E1. Furthermore, the attenuated skeletal aging and bone loss in DLX3 (Q178R) transgenic mice not only reconfirmed that DLX3 mutation (Q178R) delayed cellular senescence, but also prevented aging-mediated bone loss. Taken together, these results indicate that DLX3 mutations act as a loss of function in senescence. The delayed senescence of BMSCs leads to increased bone formation by compensating decreased osteogenic potentials with more generations and extended functional lifespan. Our findings in the rare human genetic disease unravel a novel mechanism of DLX3 involving the senescence regulation of bone formation