Browsing by Subject "Connexin43"

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    Immunohistochemistry of connexin43 and zonula occludens-1 in the myocardium as markers of early ischemia in autopsy material
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2014) Kawamoto, Osamu; Michiue, Tomomi; Ishikawa, Takaki; Maeda, Hitoshi
    Immunohistochemistry of the terminal complement complex (C5b-9) and fibronectin (FN) is useful to detect myocardial ischemia preceding necrosis in the postmortem diagnosis of sudden cardiac death. The present immunohistochemical study examined connexin43 (Cx43) and zonula occludens-1 (ZO-1) as markers of early myocardial ischemia in addition to the above-mentioned markers, using forensic autopsy cases of acute deaths due to myocardial infarction (MI, n=15) and acute ischemic heart disease (AIHD) without apparent myocardial necrosis (n=8), compared with those of acute mechanical asphyxiation (As, n=24) and drowning (D, n=10) as controls. Immunopositivities of each marker in the myocardium were semi-quantitatively graded by scoring. ZO-1, C5b-9 and FN were detected in the myocardial cytoplasm, whereas Cx43 and nonphosphorylated (np) Cx43 showed varied localizations at the intercalated disc, in the cytoplasm and along the lateral cell border. ZO-1 and FN showed a tendency to be detected more intensely in MI and IHD than in As and D. C5b-9 showed specific staining at the site of ischemia in MI (n=10/15) and AIHD (n=6/8), while the distribution of npCx43 was different in most cases of MI (n=14/15) and AIHD (n=5/8), compared with As and D; npCx43 positivity score was higher in the cytoplasm than at the intercalated disc, indicating redistribution due to myocardial ischemia. Such findings were detected in a few cases of As (n=3/24). These findings suggest that the combination of npCx43 and C5b-9 immunohistochemistry is useful for detecting early lesions of myocardial ischemia in sudden cardiac death.
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    Loss of connexin43 (Cx43) in Sertoli cells leads to spatio-temporal alterations in occludin expression
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2014) Gerber, Jonathan; Weider, Karola; Hambruch, Nina; Brehm, Ralph
    Within the testis, Sertoli cell (SC) junctional complexes between somatic SC create a basal and apical polarity within the seminiferous epithelium, restrict movement of molecules between cells, and separate the seminiferous epithelium into a basal and adluminal compartment. This barrier consists of membrane integrated proteins known as tight, adherens, and gap junctions, which promote cell-cell contact along the blood-testis-barrier (BTB). Nevertheless, these junctions, which form the basis of the BTB are structures whose function and dynamic regulation is still poorly understood. Thus, in this study, through the use of immunohistochemistry (IHC), semi quantitative western blot (WB) analysis, and real-time-quantitative-PCR (qRT-PCR) we focused on the expression pattern of the main testicular tight junction protein, occludin, in SC. For this, the established transgenic SC specific connexin 43 (Cx43) knockout (SCCx43KO) mouse line was used; both knockout (KO) and wildtype (WT) males of different ages from juvenile to adult were compared. The object was to elucidate a possible role of Cx43 on the expression pattern and regulation of occludin. This conditional KO mouse line lacks the gap junction gene Gja1 (coding for Cx43) only in SC and reveals impaired spermatogenesis. The qRT-PCR indicates an increase in occludin mRNA in adult KO mice. These results correspond to the occludin protein synthesis of adult mice. Additionally, during puberty, occludin localization at the BTB barrier in KO mice is delayed. Our study demonstrates spatiotemporal alterations in occludin mRNA- and protein-expression, indicating that Cx43 might act as a regulator for BTB formation (and function).