The Mineralocorticoid Hormone Receptor and Action in the Eye

Mirshahi, Massoud; Nicolas, C.; Mirshahi, Ali; Hecquet, Christiane; D’Hermies, F; Faure, Jean‐Pierre; Agarwal, M.K.

doi:10.1006/bbrc.1996.0197

Cited by 37 publications

(46 citation statements)

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“…Figure 1 show that the cytosol from the proerythroblastic TF1 (a) and the HEL (c) cell lines were resolved as a single band of about 102 kDa in Western blots developed with the aid of the polyclonal antibody directed against the entire mineralocorticoid receptor (MCR), but the myeloblastic cell line (U937) did not exhibit this protein at all (b). This is comparable to the molecular weight in a number of other organs that are known to contain the MCR, [22][23][24][25][26] and correlates well with the theoretical molecular mass of 107 kDa calculated from the cloned product.…”

Section: Chemicals and Reagentssupporting

confidence: 79%

“…21 The steroid binds to the receptor by noncovalent forces but chemical crosslinking is possible. [22][23][24][25] The photochemical bond between the ligand and the MCR (Figure 2) in the presence of 3 H-R 5020 resulted in a 102 kDa band (lane b), confirming the results with immunoblots. The labelling was eliminated when RU 26752, a ligand specific to the MCR, 4 was allowed to compete with 3 H-R 5020 (lane d).…”

Section: Data Insupporting

confidence: 78%

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Demonstration of the mineralocorticoid hormone receptor and action in human leukemic cell lines

Mirshahi

Golestaneh

et al. 2000

Leukemia

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We studied the expression of the mineralocorticoid receptor (MCR), and of the amiloride-sensitive sodium channel (ASSC) regulated by the MCR, in human leukemic cell lines. Cell extracts from TF1 (proerythroblastic), HEL (human erythroblastic leukemia) and U937 (myeloblastic) cell line were positive for the ASSC, as a 82 kDa band in Western blots developed with the aid of a polyclonal antibody raised against the peptide QGLGKGDKREEQGL, corresponding to the region 44-58 of the ␣ subunit of the epithelial sodium channel (ENaC) cloned from rat colon, linked to KLH. The polyclonal antibody against the MCR revealed a single band of about 102 kDa in extracts from HEL and TF1 cells. The immunofluorescent labelling of the MCR in all cell lines showed a nucleocytoplasmic localization of the receptor but the ASSC was exclusively membrane-bound and these results were confirmed by confocal microscopy. The expression of the MCR in the HEL cells was evident as a predicted band of 843 bp (234 amino acids) in electrophoresis of the PCR product obtained after total RNA had been reverse transcribed and then amplified using the primers 5′-AGGCTAC-CACAGTCTCCCTG-3′ and 5′-GCAGTGTAAAATCTCCAGTC-3′ (sense and antisense, respectively). The ENaC was similarly evident with the aid of the primers 5′-CTGCCTTTATG GATGATGGT-3′ (sense) and 5′-GTTCAGCTCGAAGAAGA-3′ (antisense) as a predicted band of 520 bp. In both cases, 100% identity was observed between the sequences of the PCR products compared to those from known human sources. The multiplication of the HEL cells was influenced by antagonists (RU 26752, ZK 91587) targeted for specificity to the MCR and this was selectively reversed by the natural hormone aldosterone. These steroids also provoked chromatin condensation in the HEL population. These permit new and novel possibilities to understand the pathobiology of human leukemia and to delineate sodium-water homeostasis in nonepithelial cells. Leukemia (2000) 14, 1097-1104.

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Section: Chemicals and Reagentssupporting

confidence: 79%

Section: Data Insupporting

confidence: 78%

Demonstration of the mineralocorticoid hormone receptor and action in human leukemic cell lines

Mirshahi

Golestaneh

et al. 2000

Leukemia

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“…Immunohistochemical localization of the mineralocorticoid receptor (Mirshahi et al, 1996(Mirshahi et al, , 1997Stokes et al, 2000;Suzuki et al, 2001) and the glucocorticoid receptor (Stokes et al, 2000;Suzuki et al, 2001) was demonstrated in NPE cells. Corticosteroid Fluorescence observation by confocal laser microscopy.…”

Section: Discussionmentioning

confidence: 99%

“…The NPE cells that face the posterior chamber are involved in the active secretion of aqueous humor (Usukura et al, 1988) and have tight junctions that act as a blood-aqueous barrier (Hirsch et al, 1977;Raviola, 1974Raviola, , 1977. In addition, the NPE cells have various steroid hormone receptors (Mirshahi et al, 1996(Mirshahi et al, , 1997Stokes et al, 2000;Suzuki et al, 2001) and are considered to modulate the aqueous humor in the maintenance of ocular homeostasis.…”

mentioning

confidence: 99%

Oxysterol 7α-Hydroxylase (CYP39A1) in the Ciliary Nonpigmented Epithelium of Bovine Eye

Ito

Ueda

Ikeda

et al. 2003

Laboratory Investigation

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SUMMARY:The CYP39A1 oxysterol 7␣-hydroxylase preferentially catalyzes the 7␣-hydroxylation of 24-hydroxycholesterol and has been suggested to play a role in the alternative bile acid synthesis pathway in the liver. The presence of CYP39A1 oxysterol 7␣-hydroxylase has been reported only in the liver. To investigate the physiologic characteristics of the ciliary processes in bovine ocular tissues, we raised a mAb, 42C, against nonpigmented epithelial (NPE) cells, which have tight junctions that act as a blood-aqueous barrier and are involved in producing aqueous humor and maintaining ocular homeostasis. Immunohistochemical analysis showed that 42C antibody reacted intensely with an antigen in the NPE cells of the ciliary processes but not with other ocular tissues. The SDS-PAGE profile of immunoaffinity-purified antigens from bovine ciliary processes showed a predominant protein of molecular mass of 44.0 kDa. The amino acid sequence of this antigenic protein was identical to human CYP39A1 oxysterol 7␣-hydroxylase. Immunoreactivity with 42C antibody was found only in hepatocytes and ocular tissues. These data suggest a new physiologic function for the CYP39A1 oxysterol 7␣-hydroxylase in addition to the production of bile acids and provide new insight into the physiologic role of the ciliary NPE cells concerning the metabolism of sterols in the eye. (Lab Invest 2003, 83:349 -355).

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“…Not only MR and GR, but also 11b-HSD1, are expressed throughout the human eye (MR: corneal epithelium, endothelium, iris, non-pigmented epithelium (NPE), pigmented epithelium (PE), ciliary body and retinal pigmented epithelium (RPE); and GR: trabecular meshwork (TM), corneal epithelium, corneal endothelium, ciliary body stroma and retina) (Lin et al 1984, Weinreb et al 1985, Mirshahi et al 1996. Recent descriptive studies have localised this prereceptor regulator of GC function in the human corneal epithelium and ciliary body epithelium (Stokes et al 2000, Rauz et al 2001, Suzuki et al 2001.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the prereceptor regulation of glucocorticoids in the anterior segment of the rabbit eye

Onyimba¹,

Vijapurapu²,

Curnow³

et al. 2006

Journal of Endocrinology

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The prereceptor regulation of glucocorticoids (GCs) by 11b-hydroxysteroid dehydrogenase type-1 (11b-HSD1), a bidirectional isozyme that interconverts active (cortisol) and inactive (cortisone) GCs, is an established determinant of GC function in tissues such as liver, adipose and bone. Although the therapeutic use of GCs is abundant in ophthalmic practice, where GC interactions with nuclear receptors modulate gene transcription, the prereceptor regulation of endogenous cortisol is not well described in ocular tissues. Recent descriptive studies have localised 11b-HSD1 to the human corneal epithelium and non-pigmented epithelium (NPE) of the ciliary body, indicating a link to corneal epithelial physiology and aqueous humour production. In this study, we characterise the functional aspects of the autocrine regulation of GCs in the anterior segment of the rabbit eye. Using our in-house generated primary antibody to human 11b-HSD1, immunohistochemical analyses were performed on paraffin-embedded sections of whole New Zealand white albino rabbits, (NZWAR) eyes. As in human studies, 11b-HSD1 was localised to the corneal epithelium and the NPE. No staining was seen in the albino 'pigmented' ciliary epithelium. Specific enzyme assays for oxo-reductase (cortisone/cortisol) and dehydrogenase (cortisol/cortisone) activity indicated predominant 11b-HSD1 oxo-reductase activity from both the intact ciliary body tissue (nZ12, median 2$1 pmol/mg per h and range 1$25-2$8 pmol/mg per h; PZ0$006) and primary cultures of corneal epithelial cells (nZ12, median 3$0 pmol/mg per h and range 1$0-7$4 pmol/mg per h, PZ0$008) compared with dehydrogenase activity (median 1$0 pmol/mg per h and range 0$5-2$0 pmol/mg per h; median 0$5 pmol/mg per h and range 0$25-1$9 pmol/mg per h respectively). These findings were supported by expression of 11b-HSD1 protein as visualised by Western blotting of ciliary body tissue and immunocytochemistry of corneal epithelial cells. Reduction of corneal epithelial cell proliferation was seen after primary cultures were co-incubated with cortisol and cortisone. 11b-HSD1 activity was not demonstrated in naïve conjunctival fibroblasts or corneal stromal keratocytes. Our results indicate that the distribution of 11b-HSD1 in the rabbit resembles that of the human eye and activates cortisone to cortisol in both corneal and uveal tissues. The NZWAR provides a suitable in vivo model for the further evaluation of 11b-HSD1 activity in the eye, especially its role in corneal epithelial and ciliary body physiology.

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The Mineralocorticoid Hormone Receptor and Action in the Eye

Cited by 37 publications

References 0 publications

Demonstration of the mineralocorticoid hormone receptor and action in human leukemic cell lines

Demonstration of the mineralocorticoid hormone receptor and action in human leukemic cell lines

Oxysterol 7α-Hydroxylase (CYP39A1) in the Ciliary Nonpigmented Epithelium of Bovine Eye

Characterisation of the prereceptor regulation of glucocorticoids in the anterior segment of the rabbit eye

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