Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 4 uppsatser.

Keratoderma – pathological hyperkeratosis of palms and soles - is a cause of disability in many clinical situations, including the rare and heterogeneous group of inherited palmoplantar keratodermas (PPKs). The aim of this study was to work towards better understanding of molecular mechanisms active in the pathogenesis of PPK by the creation of a cell and tissue culture resource and its initial application to laboratory studies. My study was based on a diverse group of autosomal dominant disorders, previously ascertained in families from Scotland, in whom the precise genetic aetiology was known. I established a tissue and cell culture resource of inherited keratodermas of known single-gene aetiology from patients with proven keratin 1, 9, 17, loricrin and mitochondrial mutations. An additional pedigree with striate keratoderma with an unknown mutation was recruited, and the causative mutation identified as a novel heterozygous A-to-T transversion in exon 5 (c.430A>T) of the desmoglein 1 gene, converting an arginine residue to a premature termination codon (p. Arg144stop). The keratinocyte culture resource was established from patients with keratin 1, 9, 17 and loricrin mutations, as well as controls. Due to the pain associated with direct infiltration of plantar skin, biopsies were obtained using peripheral nerve block for plantar biopsy. The effectiveness of this approach, which may be useful for future administration of treatment, was made the subject of an open clinical trial. Histological and immunocytochemical studies were carried out on affected plantar skin obtained from PPK patients and compared to control tissue, in an attempt to identify common and distinct pathways resulting in hyperkeratosis. Histological changes, e.g. hypergranulosis, extent of hyperkeratosis, acanthosis or acantholysis, were not uniform across different subtypes of inherited PPK and varied even between individuals within subtypes. Prominent eosin staining of spinous cells was a common feature in inherited PPK due to underlying K1 and K17 mutations. Electron microscopy showed abnormal keratin filaments in PPK with underlying keratin mutations only but was not a uniform finding within subtypes, and other electron microscopic features also varied between individuals. Immunocytochemical study did not demonstrate significant differences in expression of a selection of markers of differentiation (keratins 1, 9, 14 and 17), and cornified envelope protein filaggrin. Abnormal involucrin expression was observed, with premature expression in basal and lower spinous layers in all PPK subtypes raising the possibility of a common underlying mechanism in the development of hyperkeratosis. Prominent loricrin staining was noted in areas of acantholysis in K1 and K9 subtypes, but was uniform across other subtypes. Markers of proliferation and apoptosis demonstrated no overt change in epidermal turnover, although it is possible that only small changes in proliferative index are required to produce plantar hyperkeratosis. Overall, using morphological criteria, plantar hyperkeratosis was not readily distinguishable between inherited PPK of different underlying genetic causes. This raises the possibility that many of the reported structural features of inherited PPK are secondary phenomena as opposed to critical steps in the pathogenesis of hyperkeratosis. Initial attempts at RNA extraction using laser and manual microdissection have to date been unsuccessful in generating RNA of the quality and concentration to run a pilot microarray experiment, using standard RNA extraction kits. Plans for future projects include the further development of a possible microarray experiment in the Pachyonychia Congenita type 2 pedigree with the McLean laboratory in Dundee. The tissue resource has been made available for collaborative study via the GENESKIN project, as well as through the McLean and Lane laboratories, Dundee for both functional studies and immortalisation of cell lines.

abstract: This research investigated using impedance as a minimally invasive oral cancer-screening tool by modeling healthy and diseased tissue. This research developed an ultra-structurally based tissue model for oral mucosa that is versatile enough to be easily modified to mimic the passive electrical impedance responses of multiple benign and cancerous tissue types. This new model provides answers to biologically meaningful questions related to the impedance response of healthy and diseased tissues. This model breaks away from the old empirical top down "black box" Thèvinin equivalent model. The new tissue model developed here was created from a bottom up perspective resulting in a model that is analogous to having a "Transparent Box" where each network element relating to a specific structural component is known. This new model was developed starting with sub cellular ultra-structural components such as membranes, proteins and electrolytes. These components formed the basic network elements and topology of the organelles. The organelle networks combine to form the cell networks. The cell networks combine to make networks of cell layers and the cell layers were combined into tissue networks. This produced the complete "Transparent Box" model for normal tissue. This normal tissue model was modified for disease based on the ultra-structural pathology of each disease. The diseased tissues evaluated include cancers type one through type three; necrotic-inflammation, hyperkeratosis and the compound condition of hyperkeratosis over cancer type two. The impedance responses for each of the disease were compared side by side with the response of normal healthy tissue. Comparative evidence from the models showed the structural changes in cancer produce a unique identifiable impedance "finger print." The evaluation of the "Transparent Box" model for normal tissues and diseased tissues show clear support for using comparative impedance measurements as a clinical tool for oral cancer screening. / Dissertation/Thesis / normal oral mucosal tissue model / cancer type 1 oral mucosal tissue model / cancer type 2 oral mucosal tissue model / cancer type 3 oral mucosal tissue model / hyperkeratosis oral mucosal tissue model / hyperkeratosis over cancer type 2 oral mucosal tissue / necrotic inflammation oral tissue model / Ph.D. Electrical Engineering 2012

Autosomal dominant epidermolytic ichthyosis (EI) is a rare disease characterized by intra-epidermal blistering due to mutations in either of two keratin genes, KRT1 and KRT10, expressed by suprabasal keratinocytes. Autosomal recessive congenital ichthyosis (ARCI) is a non-blistering, hyperkeratotic disease caused by mutations in one of the following genes: ABCA12, ALOX12B, ALOXE3, TGM1, CYP4F22, NIPAL4 and SLC27A4, which are all essential for skin barrier homeostasis. ARCI and EI often respond well to treatment with retinoids, but the mechanism of action is unclear. The aim of this thesis was to increase the knowledge of pathogenic pathways in ichthyosis and to find new explanations to the effect of retinoids. In vitro studies of immortalized keratinocytes from EI patients showed an abnormal keratin aggregation after heat stress, that could be partially inhibited by pre-treatment with all-trans retinoic acid (ATRA) or retinoic acid receptor α-agonists. ATRA treatment also reduced the relative expression of mutated vs wildtype KRT10. The clearance of ATRA in human keratinocytes was found to be mediated by CYP26B1. In skin biopsies from ARCI patients, immunofluorescence analysis of 12R-LOX, eLOX-3, TGM1, ichthyin and FATP4 showed altered expression, not only of the mutated protein, but also of the other proteins. These observations are consistent with a feedback regulatory mechanism by which the loss of one protein results in an up-regulation of other proteins. Furthermore, 12R-LOX, eLOX-3 and TGM1 were intimately co-localized in stratum corneum, as were ichthyin and FATP4, suggesting that the proteins are linked to the same metabolic pathway. When treated with a CYP26 inhibitor known to raise the endogenous ATRA level of the skin, two patients with NIPAL4 mutations, initially exhibiting increased co-localization signals for 12R-LOX and eLOX-3, displayed normalized lipoxygenase expressions and showed clinical improvement. In conclusion, mechanisms are proposed by which pathogenic keratin aggregations in EI and epidermal protein deficiencies in ARCI patients may be mitigated by retinoids. Furthermore, the vivid crosstalk between proteins incriminated in ARCI suggests that these enzymes operate along a common metabolic pathway essential for producing barrier lipids in stratum corneum. Any abrogation of this production may cause barrier failure, hence resulting in a compensatory hyperkeratosis characteristic of congenital ichthyosis.

The thesis explores an issue of mastitis in dairy cows, and factors that influence the health of a mammary gland. In span of 2012-2013, 629 quarter samples of milk were collected, the somatic cells count (SCC) was determined and the results related to the condition of teats base, and also to an order and phase of lactation. The results were compared to the pool samples collected in 2008-2013 (SCC, TBC) and the number and development of clinical mastitis was followed (2012-2013). The condition of teats base was estimated as an important factor contributing to the health of a mammary gland. The lowest SCC was identified in the first phase of lactation, and, contrary to that, the highest SCC was identified in the third phase of lactation (active involution). The order of lactation proved to be an important factor influencing SCC in milk. Dairy cows staying in pasture were shown to have less SCC in milk; it can therefore be concluded that grazing has a positive impact on SCC in milk. In the examined period, very low number of clinical mastitis was determined

L'espèce canine (Canis lupus familiaris) rassemble plus de 350 races issues d'une sélection artificielle drastique menée par l'Homme au cours des derniers siècles. De ce fait, chaque race peut être considérée comme un isolat génétique développant chacune des affections génétiques de manière spontanée avec parfois de fortes fréquences. Ainsi, l'espèce canine constitue un modèle puissant pour identifier les gènes et allèles responsables de ces affections homologues à certaines maladies génétiques humaines. Mon premier projet a porté sur la recherche des causes génétiques de deux kératodermies plantaires chez le terrier irlandais et le dogue de Bordeaux. En combinant plusieurs analyses d'association (GWAS : « Genome Wide Association Study ») et des techniques de séquençage NGS (Next Generation Sequencing), un nouveau gène muté a été identifié pour le terrier irlandais. Concernant les dogues de Bordeaux, nous avons génotypé plus de 170 000 SNPs sur plus de 200 dogues. Une analyse de liaison génétique a permis d'identifier un locus de 20 Mb sur le chromosome 9 contenant un cluster de kératines. En combinant les données cliniques et génétiques, la kératine 16 s'avérait le meilleur gène candidat. Son séquençage complet a permis d'identifier une mutation complexe générant une protéine tronquée. Des analyses de PCR quantitatives ont révélé que ce gène muté était sous exprimé chez les individus atteints. Ce travail nous permet donc de proposer cette race de chien comme le premier modèle animal spontané de kératodermie focale non-épidermolytique (FNEPPK). En parallèle de ce projet, j'ai mené des recherches sur les bases moléculaires d'un syndrome d'automutilation acrale décrit dans plusieurs races. Cette neuropathie est homologue aux neuropathies héréditaires sensitives et autonomes (HSANs) chez l'Homme et se caractérise par une perte de sensibilité à la douleur au niveau des membres. A partir d'un GWAS, j'ai pu identifier un locus de 1,5 Mb chez le chien, dont l'orthologue humain n'est pas encore décrit chez des patients HSANs. Le séquençage complet de ce locus a mené à l'identification d'un variant situé dans une région cis-enhancer en amont d'un gène candidat. La mise en évidence d'une sous-expression du gène candidat indique que ce variant régulateur semblerait modifier l'activité de l'enhancer nous permettant de le proposer comme la mutation causale chez le chien. Cette découverte offre donc de nouvelles perspectives de recherche pour des patients humains atteints de neuropathies héréditaires sensitives. En combinant des approches génétiques complémentaires sur des modèles spontanés de maladies bien caractérisées chez le chien, j'ai pu participer à l'identification de trois nouveaux gènes, dont deux excellents candidats pour ces maladies homologues humaines. Le troisième représente un vrai modèle spontané de kératodermie K16, ouvrant ainsi des perspectives thérapeutiques qui bénéficieront à l'Homme et au chien. / The dog species (Canis lupus familiaris) contains more than 350 distinct breeds resulting from human drastic selection during the last centuries. Each breed can then be considered as a genetic isolate, developing specific spontaneous genetic diseases with high frequencies. Thus, dogs constitute a powerful model to identify new genes and alleles involved in disorders homologous to human diseases. For my thesis, I worked on two main topics. The first one focused on the search of the genetic causes of two footpad keratodermas in the Irish terrier and the dogue de Bordeaux breeds. Concerning the Irish terrier, the work was conduced by Tosso Leeb’s team in the University of Berne, in collaboration with the Antagene Company. Using a Genome Wide Association Study (GWAS) and Next Generation Sequencing (NGS), the mutation in a new gene has been identified in footpad hyperkeratosis in this breed. For the dogue de Bordeaux project, we genotyped more than 170 000 SNPs on over 200 dogs. We then performed a genetic linkage study with a subset of 68 dogs, including 14 affected dogs. We identified a significant locus of 20 Mb on the canine chromosome 9 containing one keratin cluster. Comparing clinical, histopathological and immunochemistry data, keratin 16 appeared as an excellent candidate. The sequencing of the gene revealed a complex mutation leading to a non-functional truncated K16 protein. Quantitative RT-PCR analyses showed a strong decrease of the level of KRT16 expression in affected footpads. These results led to propose the dogue de Bordeaux footpad hyperkeratosis as the first spontaneous model of focal non-epidermolytic palmoplantar keratoderma (FNEPPK). In parallel, I studied an acral mutilation syndrome described in several hunting dog breeds. This neuropathy corresponds to human hereditary sensory and autonomic neuropathies (HSANs) and is characterized by an insensitivity to pain only in the limb. With a classical GWAS strategy, using 24 affected and 30 unaffected dogs, we identified a 1.5 Mb locus in dogs, the human orthologous locus being still unknown in human patients. Targeted sequencing of this locus revealed one single variant localized in a cis-enhancer region closed to a strong candidate gene. A lower level of expression of the candidate gene in affected dogs seems to show a functional effect of the mutation in the enhancer activity. These results led to propose this variant as the causative mutation for this canine neuropathy, and so this canine model as an opportunity to identify a new human HSAN gene. Combining complementary genetic approaches on spontaneous models of well characterized canine diseases, I did participated to the identification of three new genes, two of which being novel excellent candidates for the homologous human diseases. The third represents a true homologous model of KRT16 human keratoderma, opening the field to the development of new treatments benefiting to both humans and dogs.

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