Grzegorz Dyduch

Heme Oxygenase-1 Inhibits Myoblast Differentiation by Targeting Myomirs

AIMS Heme oxygenase-1 (HMOX1) is a cytoprotective enzyme degrading heme to biliverdin, iron ions, and carbon monoxide, whose expression is induced in response to oxidative stress. Its overexpression has been suggested as a strategy improving survival of transplanted muscle precursors. RESULTS Here we demonstrated that HMOX1 inhibits differentiation of myoblasts and modulates miRNA processing: downregulates Lin28 and DGCR8, lowers the total pool of cellular miRNAs, and specifically blocks induction of myomirs. Genetic or pharmacological activation of HMOX1 in C2C12 cells reduces the abundance of miR-1, miR-133a, miR-133b, and miR-206, which is accompanied by augmented production of SDF-1 and miR-146a, decreased expression of MyoD, myogenin, and myosin, and disturbed formation of myotubes. Similar relationships between HMOX1 and myomirs were demonstrated in murine primary satellite cells isolated from skeletal muscles of HMOX1(+/+), HMOX1(+/-), and HMOX1(-/-) mice or in human rhabdomyosarcoma cell lines. Inhibition of myogenic development is independent of antioxidative properties of HMOX1. Instead it is mediated by CO-dependent inhibition of c/EBPδ binding to myoD promoter, can be imitated by SDF-1, and partially reversed by enforced expression of miR-133b and miR-206. Control C2C12 myoblasts injected to gastrocnemius muscles of NOD-SCID mice contribute to formation of muscle fibers. In contrast, HMOX1 overexpressing C2C12 myoblasts form fast growing, hyperplastic tumors, infiltrating the surrounding tissues, and disseminating to the lungs. INNOVATION We evidenced for the first time that HMOX1 inhibits differentiation of myoblasts, affects the miRNA processing enzymes, and modulates the miRNA transcriptome. CONCLUSION HMOX1 improves the survival of myoblasts, but concurrently through regulation of myomirs, may act similarly to oncogenes, increasing the risk of hyperplastic growth of myogenic precursors.

Eosinophilic fasciitis successfully treated with cyclosporine

We report on a 45-year-old female who developed eosinophilic fasciitis, characterized by scleroderma-like skin indurations, predominantly on the extremities and chest, with joint contractures and intermittent blood eosinophilia. Histologic examination revealed fibrosis of muscle fascia and eosinophilic infiltration. High-dose systemic corticosteroid therapy was ineffective, but cyclosporine treatment led to remission.

Increased nitric oxide availability attenuates high fat diet metabolic alterations and gene expression associated with insulin resistance

BackgroundHigh fat diet impairs nitric oxide (NO) bioavailability, and induces insulin resistance. The link between NO availability and the metabolic adaptation to a high fat diet is not well characterized. The purpose of this study was to investigate the effect of high fat diet on metabolism in mice with decreased (eNOS-/-) and increased (DDAH overexpressed) NO bioavailability.MethodseNOS-/- (n = 16), DDAH (n = 24), and WT (n = 19) mice were fed a high fat diet (HFD) for 13 weeks. Body weight, biochemical parameters, adipokines and insulin were monitored. The matrigel in vivo model with CD31 immunostaining was used to assess angiogenesis.Gene expression in adipose tissues was analyzed by microarray and Real Time PCR. Comparisons of the mean values were made using the unpaired Student t test and p < 0.05 were considered statistically significant.ResultseNOS-/- mice gained less weight than control WT and DDAH mice. In DDAH mice, a greater increase in serum adiponectin and a lesser increment in glucose level was observed. Fasting insulin and cholesterol levels remained unchanged. The angiogenic response was increased in DDAH mice. In adipose tissue of DDAH mice, genes characteristic of differentiated adipocytes were down-regulated, whereas in eNOS-/- mice, genes associated with adipogenesis, fatty acid and triglyceride synthesis were upregulated.ConclusionsOur results indicate that increased NO availability attenuates some HFD induced alterations in metabolism and gene expression associated with insulin resistance.

Induced pluripotent stem cells as a model for diabetes investigation.

Mouse and human induced pluripotent stem cells (iPSCs) may represent a novel approach for modeling diabetes. Taking this into consideration, the aim of this study was to generate and evaluate differentiation potential of iPSCs from lepdb/db (db/db) mice, the model of diabetes type 2 as well as from patients with Maturity Onset Diabetes of the Young 3 (HNF1A MODY). Murine iPSC colonies from both wild type and db/db mice were positive for markers of pluripotency: Oct3/4A, Nanog, SSEA1, CDy1 and alkaline phosphatase and differentiated in vitro and in vivo into cells originating from three germ layers. However, our results suggest impaired differentiation of db/db cells into endothelial progenitor-like cells expressing CD34 and Tie2 markers and their reduced angiogenic potential. Human control and HNF1A MODY reprogrammed cells also expressed pluripotency markers: OCT3/4A, SSEA4, TRA-1–60, TRA-1-81, formed embryoid bodies (EBs) and differentiated into cells of three germ layers. Additionally, insulin expressing cells were obtained from those partially reprogrammed cells with direct as well as EB-mediated differentiation method. Our findings indicate that disease-specific iPSCs may help to better understand the mechanisms responsible for defective insulin production or vascular dysfunction upon differentiation toward cell types affected by diabetes.

Angiogenesis in the New Zealand obese mouse model fed with high fat diet

BackgroundObesity and its complications lead to vascular injury, atherosclerosis, diabetes and pathological angiogenesis. One of the models to study the obesity and its entanglements is the New Zealand Obese mice model. Aim of this study was to check the effect of high fat diet on changes in biochemical parameters as well as on process of angiogenesis in NZO mice.MethodsNZO mice were fed with standard (ST) or high fat (HF) diet for seven weeks. Body weight and serum biochemical parameters were monitored. The PECAM1 positive vessel-like structures immunostaining, as well as the gene expression of the matrigel penetrating cells by microarray (confirmed by real-time PCR method) were analyzed.ResultsMice fed with HF diet developed obesity. Number of newly created vessels with lumen was correlated with hyperglycemia and animal weight gain. The number of PECAM1 positive cells in matrigel tended to increase during HF diet. Microarray results revealed changes in gene expression (activation of the oxidative stress and insulin resistance, inhibition of apoptosis and cell differentiation), however without markers of endothelial cell network maturation.ConclusionObserved changes in the NZO mice on HF diet argue for the hyperglycemia related activation of angiogenesis, leading to the formation of pathological, immature network.

Automated epidermis segmentation in histopathological images of human skin stained with hematoxylin and eosin

Background: Epidermis area is an important observation area for the diagnosis of inflammatory skin diseases and skin cancers. Therefore, in order to develop a computer-aided diagnosis system, segmentation of the epidermis area is usually an essential, initial step. This study presents an automated and robust method for epidermis segmentation in whole slide histopathological images of human skin, stained with hematoxylin and eosin. Methods: The proposed method performs epidermis segmentation based on the information about shape and distribution of transparent regions in a slide image and information about distribution and concentration of hematoxylin and eosin stains. It utilizes domain-specific knowledge of morphometric and biochemical properties of skin tissue elements to segment the relevant histopathological structures in human skin. Results: Experimental results on 88 skin histopathological images from three different sources show that the proposed method segments the epidermis with a mean sensitivity of 87 %, a mean specificity of 95% and a mean precision of 57%. It is robust to inter- and intra-image variations in both staining and illumination, and makes no assumptions about the type of skin disorder. The proposed method provides a superior performance compared to the existing techniques.

Impaired leptin activity in New Zealand Obese mice: model of angiogenesis

Leptin is prompt to drive angiogenesis, effecting proper vascularisation. Tissue remodeling (including adipose organ) is associated with the angiogenic response. The aim of this study was to investigate the effect of hyperleptinemia on angiogenesis in subcutaneous (s.c.) in vivo matrigel model in mice on a high fat (HF) diet. HF promoted adipose tissue accumulation and biochemical changes resembling metabolic syndrome. However, the impact of this dietary treatment on angiogenesis, measured in s.c. matrigel model was not significant. Changes in leptin concentration were not accompanied by significant angiogenic response. This lack of leptin activity and impaired signal transduction at the molecular level suggests malfunction of the leptin receptor in NZO mice.

Adult‐onset eccrine angiomatous hamartoma on the vulva

Eccrine angiomatous hamartoma (EAH) is a benign, cutaneous tumor characterized histologically by the proliferation of eccrine glands and capillaries. Lotzbeck first described this rare entity in 1859 as an angioma-like tumor on the cheek of a child, and over a century later, the lesion was coined by Heyman et al. as eccrine angiomatous hamartoma. EAH typically occurs on the extremities of children; however, rare cases have been described to occur in the adult population and in atypical locations, including the forehead, sacrum, and buttock. To our knowledge, we are the first to report EAH on the vulva of an adult woman. A healthy 29-year-old woman had presented with a scaly, erythematous plaque of 1.5 cm in diameter on the vulva, present for four years. The lesion was asymptomatic, lacking hyperhidrosis and pain. The patient reported no previous trauma or infection in the area. Additionally, there were scaly lesions on the soles, anterior aspects of knees, groin, and trunk, present since childhood and diagnosed in the past as ichthyosis. Histopathological examination of the vulvar lesion showed a marked, irregular epidermal hyperplasia with focal parakeratosis and absence of the granular layer (Fig. 1). In the superficial dermis, there were an increased number of dilated and congested capillaries. Additionally, a nodular proliferation of eccrine glands, intimately admixed with numerous small vessels in the mid-dermis, was noted (Fig. 2). Discussion

Modulatory effect of high saturated fat diet-induced metabolic disturbances on angiogenic response in hepatocyte RXRα knockout mice.

Metabolic syndrome and diabetes lead to pathological angiogenesis and angiopathy. Metabolic disturbances occur as an effect of genetic and environmental interaction. Hyperleptinemia accompanies obesity and leptin is a potent proangiogenic factor. The aim of the study was to investigate the effect of high fat diet-induced alterations in gene expression and angiogenic response in the hRXRα ko mice lacking of hyperglycemia. hRXRα ko and control mice were fed either standard or high saturated fat (HF) diet for 7 weeks. Body weight and biochemical parameters (glucose, triglycerides, cholesterol), insulin and adipokines (leptin, adiponectin) were monitored. At sixth week of feeding, mice were subcutaneously injected for 6 days with matrigel containing bFGF. Then, matrigel plugs were used for immunohistochemical staining of cells with CD31 antibody and gene expression assessment (by microarray confirmed for some genes with quantitative real time PCR). For description of angiogenesis CD31 positive structures were counted in the matrigel sections. HF diet feeding of the hRXRα ko mice resulted in increased serum cholesterol and leptin level and in tendency to decrease angiogenesis (number of vessels with lumen). The microarray studies revealed that HF diet down-regulated genes related to angiogenesis (Nos3, Kdr) and up-regulated genes connected with apoptosis (activators of caspase 3, proapoptotic genes Bcl2) and proinflammatory pathway (NfκB pathway, Tnfα). Summing up, HF diet feeding of hRXRα ko mice resulted in dyslipidemia and hyperleptinemia as well as impaired angiogenic response, and cell apoptosis. These results argue for independent participation of dyslipidemia and hyperleptinemia in pathology of angiogenic response associating metabolic syndrome.

Prostate cancer with different ERG status may show different FOXP3-positive cell numbers

Prostatic carcinoma is the most frequent cancer in males in the Western world. A significant proportion of these cancers have a recurrent translocation involving ETS family genes, which leads to the overexpression of ERG transcription factor. Prostate cancers, which bear this mutation, differ in a number of features, including tumor microenvironment. One of the components of the tumor microenvironment is FOXP3 positive lymphocytes, which may participate in breaking immunosurveillance and promoting tumor growth. The aim of the study was to analyze the relationships between ERG expression, number of FOXP3 positive cells and other features of the tumor. The study group consisted of 65 cases. Tissue microarrays composed of 2 mm tissue cores were used for immunohistological evaluation. Immunohistochemistry for ERG and FOXP3 was performed according to the routinely applied protocol. The FOXP3 positive cells were counted and the results were expressed as the number of cells per mm2. The average number of FOXP3 positive cells was 33.30/mm2 for all cases, 21.43/mm2 for the ERG negative and 42.28/mm2 for the ERG positive group (p < 0.02). There were no significant relationships between FOXP3 positive cell count and any other parameters studied. Our results suggest that the immune response may differ between ERG negative and ERG positive prostatic carcinomas.