Kallikrein-related peptidases (KLKs) are a subgroup of serine proteases of undisputable importance for a variety of functions, whose dysregulation has been linked to several pathological phenotypes. Among those pathologies, the Netherton syndrome stands out, since it is one of the very few that has its mechanism directly linked to KLK proteases as the main culprit of the disease, namely KLK5, KLK7 and to a lesser degree, KLK14. In this case, a mutation in the SPINK5 gene leads to uncontrolled hyperactivity of those proteases, which results in epidermal barrier breach due to excessive epidermal desquamation and severe inflammation of the skin. Inflammation mechanisms of NS are still relatively poorly understood, with important roles being attributed to the activities of KLKs in the processing of immune system molecules and also to the dysregulation of the cutaneous microbiome. TNFα signalling plays a key role in the homeostasis and immune response in the skin. Chronic skin infections may lead to deleterious effects with strong participation of TNFα signalling. To address the degree of its effects on the pathogenesis of NS, we have created a mouse model where the TNFR1 is disrupted by knockout of the Tnfr1 gene on the background of a previously established mouse model of the Netherton syndrome. We...

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20561号 / 医博第4246号 / 新制||医||1022(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 松田 秀一, 教授 瀬原 淳子, 教授 妻木 範行 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21617号 / 医博第4423号 / 新制||医||1033(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 羽賀 博典, 教授 川口 義弥, 教授 妹尾 浩 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Psoriasis is a chronic, immune-mediated inflammatory skin disease. Its pathogenesis is associated with dysregulated cooperation among keratinocytes, innate and adaptive immune cells, coupled with environmental triggers, including microbiota. The aim of our study was to describe the microbiota composition in psoriasis and explore the role of bacteria and fungi in the pathogenesis of this disease. We used a mouse model of psoriasis induced by topical application of imiquimod (IISI) in both germ-free (GF) mice and conventional (CV) mice with microbiota manipulated by administration of a mixture of broad-spectrum antibiotics (ATB). ATB treatment markedly changed the intestinal but not the skin bacterial diversity and led to higher resistance to IISI in CV mice. Metronidazole was the most effective antibiotic, alleviating IISI symptoms in CV, but not in GF mice. This confirms that the effect of metronidazole on IISI was microbiota- dependent. Additionally, we characterized the microbiota composition of psoriatic lesions and unaffected skin in psoriatic patients compared to healthy controls, as well as the impact of different sampling approaches on uncovering cutaneous microbiota composition. We observed significant differences in α- and β-diversities when comparing identical samples sequenced on V1V2...

No description available.

Osteoarthritis is the most common form of arthritis. Genetic models have been developed to determine if and how a targeted gene may influence cartilage degenerative changes. The itga1-null mouse model has an inhibited integrin α1B1 through a ubiquitous integrin α1 subunit knockout, which leads to fibrosis in articular cartilage through excessive signalling from transforming growth factor beta (TGFB). Depleting this TGFB signalling is proposed to have a protective effect on cartilage. This project is part of a foregoing study where a cartilage-specific knockout of TGFB receptor type II (TBRII) was used to deplete TGFB signalling in articular cartilage of the itga1-null mice to reduce the severity of cartilage degradation. This project continues the analysis of the genetic model into bone architecture at the knee. Mouse hindlimbs were scanned at a 13μm resolution using micro-computed tomography and segmented into 3D datasets containing calcified tissues and bone of the knee and surroundings. Quantification methods for trabecular bone parameters (bone volume fraction, trabecular separation, and trabecular thickness) and ectopic calcification of soft tissues were developed. Loss of trabecular bone around the involved joint is a hallmark of post-traumatic osteoarthritis. However, the results from this study showed no significant changes in trabecular bone of itga1-null mouse knees despite observing severe osteoarthritic changes in the adjacent cartilage. There were no significant effects in peri-articular trabecular bone when the TBRII knockout in cartilage was activated, but there were significant increases in ectopic calcifications of the menisci and collateral ligaments. These ectopic calcifications were also seen in tamoxifen control mice, suggesting that tamoxifen, along with TBRII depletion in cartilage, had a role in increased abnormal calcifications. Although integrin α1B1 inhibition appears to have an important role in cartilage degeneration, it does not appear to influence the bony changes that normally accompany post-traumatic arthritis. / Thesis / Master of Applied Science (MASc) / Osteoarthritis is a common joint disorder, associated mainly with cartilage degradation. Some genes have been identified that cause or prevent osteoarthritis. A previous study used two of these genes in a genetic mouse model to explore how osteoarthritis may develop. Removing the integrin α1 subunit from mice caused osteoarthritic changes in the cartilage of the mouse knee. When the transforming growth factor beta gene was removed from the cartilage, these changes were less severe. This project continued the study by exploring changes in bone around the mouse knee. We quantified bone changes around the mouse knee using high-resolution micro-computed tomography scans. Contrary to common findings in post-traumatic osteoarthritis, we found that there were no significant changes in the bone around the knees even where severe cartilage changes had been identified. However, there were significant increases in calcifications of soft tissues including the meniscus and ligaments around the knee.

No description available.

Chronic kidney disease (CKD) is a worldwide health burden with increases risk of end-stage renal function if left untreated. CKD induced in the context of metabolic syndrome (MS) increases risks of hypertension, hyperglycemia, excess body fat and dyslipidemia. Our Centre previously generated a renin-dependent hypertensive/ type 1 diabetic mouse model and lead to the development of several signs associated with human diabetic kidney disease (DKD), however the extent and impact of dyslipidemia in this model remains unknown. We hypothesized that combining a high-fat diet (HFD) regimen onto the hypertensive/ diabetic phenotype would mimic features of MS induced-CKD in mice. An 8-week-old male genetically hypertensive mice (Lin+) were subjected to streptozotocin (STZ) intraperitoneal (i.p.) injections (50 mg/kg, 5 days consecutive) to induce hyperglycemia. Four-weeks later hypertensive/ diabetic mice (Lin+ mouse with induced beta cells death, also known as LinSTZ) were fed a 60% kCal HFD for 8 weeks. This study shows that HFD-fed LinSTZ mice developed less glomerular hypertrophy, scarring and albuminuria and hepatocytes fat accumulation at endpoint than regular-diet fed littermates. Moreover, antidiabetic drug Canagliflozin, dosed at 30 mg/kg body weight, showed reno-protection in the LinSTZ mice model. Taken together, our results show that LinSTZ mice fed a HFD did not lead to a more robust model of MS induced CKD. In fact, several indices of renal injury were reduced by feeding LinSTZ mice a HFD or treating them with Canagliflozin.

Indiana University-Purdue University Indianapolis (IUPUI) / Trisomy 21 occurs in approximately 1 out of 750 live births and causes brachycephaly, a small oral cavity, a shortened mid-face, and mental impairments in individuals with Down syndrome (DS). Craniofacial dysmorphology occurs in essentially all individuals with trisomy 21 and causes functional difficulties. Mouse models are commonly used to study the etiology of human disorders because of the conserved phenotypes between species. The Ts65Dn Down syndrome mouse model has triplicated homologues for approximately half the genes on human chromosome 21 and exhibits many phenotypes that parallel those found in individuals with DS. Specifically, newborn and adult Ts65Dn mice display similar craniofacial defects as humans with DS. Ts65Dn embryos also exhibit smaller mandibular precursors than their euploid littermates at embryonic day 9.5 (E9.5). Furthermore, Ts65Dn mice exhibit reduced birth weight which suggests a possible generalized delay in overall embryonic growth. Based on previous research at E9.5, it was hypothesized that Ts65Dn E13.5 embryos would have reduced mandibular precursors with altered gene expression. It was also hypothesized that other neural crest derived structures would be reduced in trisomic embryos. Using morphological measurements it was determined that the mandible, Meckel’s cartilage, and hyoid cartilage were significantly reduced in E13.5 trisomic embryos. The tongue was of similar size in trisomic and euploid embryos while cardiac and brain tissue volumes were not significantly different between genotypes. Analysis of total embryonic size at E9.5 and E13.5 revealed smaller trisomic embryos with developmental attenuation that was not related to maternal trisomy. A microarray analysis performed on the mandibular precursor revealed 155 differentially expressed non-trisomic genes. Sox9 was of particular interest for its role in cartilage condensation and endochondral ossification. It was hypothesized that the overexpression of Sox9 in the developing mandible would be localized to Meckel’s and hyoid cartilages. Immunohistochemistry performed on the mandibular precursor confirmed an overexpression of Sox9 in both Meckel’s and the hyoid cartilages. This research provides further insight into the development of trisomic tissues, both neural crest and non-neural crest-derived, and also the specific molecular mechanisms that negatively affect mandibular development in Ts65Dn mice and presumably individuals with Down syndrome.

No description available.