Basal cells in a simple secretory epithelium adhere to the extracellular matrix (ECM), providing contextual cues for ordered repopulation of the luminal cell layer. Early high-grade prostatic intraepithelial neoplasia (HG-PIN) tissue has enlarged nuclei and nucleoli, luminal layer expansion and genomic instability. Additional HG-PIN markers include loss of alpha 6 beta 4 integrin or its ligand laminin-332, and budding of tumor clusters into laminin-511-rich stroma. We modeled the invasive budding phenotype by reducing expression of alpha 6 beta 4 integrin in spheroids formed from two normal human stable isogenic prostate epithelial cell lines (RWPE-1 and PrEC 11220). These normal cells continuously spun in culture, forming multicellular spheroids containing an outer laminin-332 layer, basal cells (expressing alpha 6 beta 4 integrin, high-molecular-weight cytokeratin and p63, also known as TP63) and luminal cells that secrete PSA (also known as KLK3). Basal cells were optimally positioned relative to the laminin-332 layer as determined by spindle orientation. beta 4-integrin-defective spheroids contained a discontinuous laminin-332 layer corresponding to regions of abnormal budding. This 3D model can be readily used to study mechanisms that disrupt laminin-332 continuity, for example, defects in the essential adhesion receptor (beta 4 integrin), laminin-332 or abnormal luminal expansion during HG-PIN progression.

Muscle spindle fibers are specialized stretch receptors that allow the perception and coordination of limb movement. Differentiation of muscle spindles is initiated by signals derived from the in growing Ia sensory neurons during development. The sensory neuron secretes neuregulin which binds and signals through the ErbB receptors to initiate a signaling cascade. This cascade results in the expression of a specific repertoire of genes, one of which is the transcription factor Egr3, which is necessary in the development of muscle spindles. Signaling occurs efficiently when the postsynaptic receptors are clustered into large aggregates in apposition to an innervating nerve. Using what is known about acetylcholine receptor clustering at neuromuscular junctions as a model, this study shows the importance of the basal lamina proteins agrin and laminin and their shared receptor ??-dystroglycan in aggregating ErbB receptors at sensory synapses. The study also shows that signaling through these receptors subsequently results in increased expression of Egr3, the transcription factor critical to muscle spindle fiber differentiation. Using an ??-dystroglycan silenced culture, it is shown that ??-dystroglycan is necessary to induce neuregulin, laminin and agrin induced Egr3. In these same myotube cultures there is also a reduced number of AChR-ErbB3 colocalized aggregates and this is not rescued with the addition of laminin. Taken together, these results suggest an essential role for basal lamina components and ??-dystroglycan, molecules that are crucial in acetylcholine receptor aggregation at neuromuscular junctions, in the induction of the transcription factor Egr3, a critical transcription factor involved in muscle spindle fiber differentiation.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

<p>The blood-brain barrier regulates the transport into the brain and protects the central nerve system (CNS) from toxics substances. However some areas of the brain, called circumventricular organs (CVO), lack the blood-brain barrier. One of these is area postrema (AP), which is located in the brainstem immediately adjacent to the nucleus tractus solitarius (NTS). These two areas together regulate autonomic behaviours such as food intake, and also make up the vomiting center.</p><p>The hormones leptin and ghrelin, which regulate food intake, are too big to pass the blood-brain barrier, but have receptors in NTS.</p><p>In this study we used immunohistochemistry to obtain a detailed map of the different components of the blood-brain barrier in AP and NTS.</p><p>The results suggest that there is a barrier that prevents diffusion of substances from AP into NTS. However, there seems to be some vessels in NTS that have a weaker or no barrier characteristics. These vessels could provide an entrance for peripheral substances to neurons in NTS.</p>

No description available.

Laminin binding integrins 6 (CD49f) and 3 (CD49c) are persistently but differentially expressed in prostate cancer (PCa). Integrin internalization is an important determinant of their cell surface expression and function. Using flow cytometry, and first order kinetic modeling, we quantitated the intrinsic internalization rates of integrin subunits in a single cycle of internalization. In PCa cell line DU145, 6 integrin internalized with a rate constant (k(actual)) of 3.25min(-1), threefold faster than 3 integrin (1.0min(-1)), 1.5-fold faster than the vitronectin binding v integrin (CD51) (2.2min(-1)), and significantly slower than the unrelated transferrin receptor (CD71) (15min(-1)). Silencing of 3 integrin protein expression in DU145, PC3, and PC3B1 cells resulted in up to a 1.71-fold increase in k(actual) for 6 integrin. The internalized 6 integrin was targeted to early endosomes but not to lamp1 vesicles. Depletion of 3 integrin expression resulted in redistribution of 64 integrin to an observed cell-cell staining pattern that is consistent with a suprabasal distribution observed in epidermis and early PIN lesions in PCa. Depletion of 3 integrin increased cell migration by 1.8-fold, which was dependent on 61 integrin. Silencing of 6 integrin expression however, had no significant effect on the k(actual) of 3 integrin or its distribution in early endosomes. These results indicate that 3 and 6 integrins have significantly different internalization kinetics and that coordination exists between them for internalization. J. Cell. Biochem. 118: 1038-1049, 2017.

In der vorliegenden Arbeit wurden die Expressionshäufigkeiten von MAGE-A-Antigenen, E -Cadherin, Laminin-5-gamma-2, MMP2 und MMP9 in Plattenepithelkarzinomen im Kopf- und Halsbereich untersuchen. Hierbei findet der Vergleich zwischen Primärtumoren und korrespondierenden Lymphknotenmetastasen besondere Beachtung. Um die Hypothese zu verifizieren, dass die o.g. Parameter einen signifikanten Einfluss auf die Progression und Metastasierung haben, wird der Zusammenhang zwischen den in der vorliegenden Arbeit gewonnenen Ergebnissen und diversen klinischen Parametern mittels Korrelationsanalyse untersucht. / This study investigates the expression profiles of MAGE-A-antigens, e-cadherin, laminin 5 gamma 2 chain, MMP2 and MMP9 in metastatic squamous cell carcinoma of head and neck. Particulary interesting is their expression in the primary tumours and in the correspondent lymph node metastases. We have compared the above mentioned antigenes with various clinical and histopathological parameters to verify the hypothesis, that those antigenes have influence both on the progression and metastases.

Duchenne muscular dystrophy (DMD) and congenital muscular dystrophy 1A (MDC1A) are the two most common forms of muscular dystrophy in humans, caused by mutations in dystrophin and laminin α2 genes respectively. Both are severe forms of the disease that lead to premature death due and are both now known to have a significant effect on the central nervous system. This project investigated the role of both proteins involved in each of these diseases in cerebellar Purkinje cells of two murine models of disease: the mdx mouse a dystrophin-deficient model of DMD and the dy2J a laminin α2-deficient murine model of MDC1A. In the case of dystrophin further studies were undertaken in order to determine if increasing age had any effects on cerebellar function. It was found that there is no difference in electrophysiological characteristics (RMP, IR, eEPSP) of the cells when compared to appropriate control groups, nor was there any difference when young and aged dystrophin-deficient mdx groups were compared. Evoked IPSP characteristics were examined in young mdx cerebellar Purkinje cells and again no difference was found when compared to wildtype. There was a significant difference in response to the GABAA antagonist bicuculline, with wildtype increasing eEPSP amplitude by almost double that found in mdx. There was no difference in short term plasticity as measured by paired pulse facilitation in any of these groups. There was no difference in paired pulse depression at the inhibitory interneuron- Purkinje cell synapse of young wildtype and mdx cerebellar Purkinje cells. There a significant blunting of long term depression (LTD, (a form of long term synaptic plasticity) between young wildtype and mdx. When young wildtype animals were compared to aged wildtype animals LTD was found to be similar, when young mdx was compared to aged mdx, there was a recovery of LTD seen in the aged population. There was also significant differences in LTD found when littermate controls were compared to dy2J (laminin α2 mutants). A third of the phenotypic animals (dy2J) potentiated. Finally when rebound potentiation (a GABA-ergic form of long term synaptic plasticity in the cerebellum) was compared in young wildtype and mdx mice, mdx mice displayed depression, rather than the expected potentiation in contrast to potentiation (or no change) as seen in all wildtype cells.

The blood-brain barrier regulates the transport into the brain and protects the central nerve system (CNS) from toxics substances. However some areas of the brain, called circumventricular organs (CVO), lack the blood-brain barrier. One of these is area postrema (AP), which is located in the brainstem immediately adjacent to the nucleus tractus solitarius (NTS). These two areas together regulate autonomic behaviours such as food intake, and also make up the vomiting center. The hormones leptin and ghrelin, which regulate food intake, are too big to pass the blood-brain barrier, but have receptors in NTS. In this study we used immunohistochemistry to obtain a detailed map of the different components of the blood-brain barrier in AP and NTS. The results suggest that there is a barrier that prevents diffusion of substances from AP into NTS. However, there seems to be some vessels in NTS that have a weaker or no barrier characteristics. These vessels could provide an entrance for peripheral substances to neurons in NTS.