| 1. |
- Akner, Gunnar, 1953-, et al.
(författare)
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Glucocorticoid receptor inhibits microtubule assembly in vitro.
- 1995
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Ingår i: Molecular and cellular endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 110:1-2, s. 49-54
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Tidskriftsartikel (refereegranskat)abstract
- The effect of glucocorticoid hormones, purified glucocorticoid receptor (GR) and purified heat shock protein M(r) 90,000 (hsp90) on microtubule (MT) assembly in vitro was tested by a spectrophotometric MT assembly assay and electron microscopy. GR significantly prolonged the nucleation phase, slowed down the assembly rate and reduced the maximal amplitude of MT assembly compared with control. The effects were partially reversed by the addition of glucocorticoid hormone. GR associated with MTs. These results indicate that GR affects MT assembly in vitro, which may be a functional correlate to the structural association of GR with MTs. This implies that factors affecting GR may affect MT assembly in vivo.
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| 2. |
- Bondestam, Jonas, et al.
(författare)
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Engagement of activin and bone morphogenetic protein signaling pathway Smad proteins in the induction of inhibin B production in ovarian granulosa cells
- 2002
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Ingår i: Molecular and Cellular Endocrinology. - 0303-7207 .- 1872-8057. ; 195:1-2, s. 79-88
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Tidskriftsartikel (refereegranskat)abstract
- In the mammalian ovary cell growth and differentiation is regulated by several members of the transforming growth factor beta (TGF beta) superfamily including activins, inhibins, growth differentiation factors and bone morphogenetic proteins (BMPs). The effects of TGF beta family members are mediated to the target cells via heteromeric complexes of type I and II serine/threonine kinase receptors which activate Smad signaling protein pathways in various cell types. We have previously shown that inhibin B, a hormonally important product from human granulosa cells, is up regulated by activin and BMPs. Here, we report the use of adenoviral gene transfer methodology to manipulate the TGF beta growth factor signaling system in primary cultures of human granulosa cells. These cells are exceedingly difficult to transfect by conventional transfection methods, but were virtually 100% infected with recombinant adenoviruses expressing green fluorescent protein (GFP). Adenoviruses expressing constitutively active forms of the seven known mammalian type I activin receptor-like kinase receptors (Ad-caALK1 through Ad-caALK7) cause activation of endogenous and adenovirally transferred Smad signaling proteins so that Ad-caALK1/2/3/6 and Ad-caALK4/5/7 induced phosphorylation of the Smad1 and Smad2 pathways, respectively. Activin A and BMP-2 activated the Smad1 and Smad2 pathways as well as inhibin B production as did all the Ad-caALKs. Furthermore, overexpression of adenoviral Smad1 and Smad2 proteins without exogenously added ligands induced inhibin B production. The inhibitory Smad7 protein suppressed BMP-2 and activin induced inhibin B production. Collectively, the present data demonstrate that adenoviral gene transfer provides an effective approach for dissecting the TGF beta signaling pathways in primary ovarian cells in vitro and more specifically indicate that the Smad1 and Smad2 pathways are involved in the regulation of inhibin B production by TGF beta family ligands in the ovary.
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| 3. |
- Gustavsson, Bengt, et al.
(författare)
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Functional analysis of a variant of the thyrotropin receptor gene in a family with Graves' disease
- 1995
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Ingår i: Molecular and Cellular Endocrinology. - 0303-7207 .- 1872-8057. ; 111:2, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- Nucleotide sequence analysis of PCR fragments corresponding to the TSH-receptor (TSHR) amplified from genomic DNA collected from the four members of a family, two of which had Graves' thyrotoxicosis, revealed a nucleotide substitution in the first position of codon 36 of the TSH-receptor gene in the two patients. The nucleotide substitution was from G to C, leading to a 36D-->36H change (D36H) in the predicted amino acid sequence of the receptor. The altered sequence was also found in DNA obtained from their mother, but not in DNA from their father. We stably expressed the two receptor variants in NIH 3T3 cells, by transfection of cDNA encoding the wildtype (WT) and D36H variants of the TSHR. Neither the binding of 125I-TSH nor the responsiveness to TSH measured as cAMP formation, appeared to be different in the TSHR-D36H compared to the TSHR-WT. Furthermore, the D36H-receptor also became desensitized when exposed to TSH as did the WT-receptor.
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| 4. |
- Liu, Kui, et al.
(författare)
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Expression pattern and functional studies of matrix degrading proteases and their inhibitors in the mouse corpus luteum
- 2003
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Ingår i: Molecular and Cellular Endocrinology. - 0303-7207 .- 1872-8057. ; 205:1-2, s. 131-140
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Tidskriftsartikel (refereegranskat)abstract
- The formation of the corpus luteum (CL) is accompanied with angiogenesis and tissue remodeling and its regression involves tissue degradation. Matrix degrading proteases such as plasminogen activators (PAs) and matrix metalloproteinases (MMPs) are thought to play important roles in such controlled proteolytic processes. In this study, in situ hybridization has been used to examine the regulation and expression pattern of mRNAs coding for proteases and protease inhibitors belonging to the PA- and MMP-systems during the life cycle of the CL in an adult pseudopregnant mouse model. Of the nine proteases and five protease inhibitors that were studied, the majority were found to be temporally expressed during the formation and/or the regression of the CL. However, the mRNAs coding for urokinase type PA (uPA), membrane-type 1 MMP (MT1-MMP), and tissue inhibitor of metalloproteinases type-3 (TIMP-3) were constantly expressed in the mouse CL throughout its whole life span. To study the functional role of uPA in the CL, we analyzed luteal formation and function in uPA deficient mice. Our results revealed no significant difference in ovarian weight, serum progesterone levels, and blood vessel density in the functional CL between uPA deficient and wild type control mice. The temporal and spatial expression pattern of proteases and protease inhibitors during the CL life span suggests that members of the PA- and MMP-systems may play important roles in the angiogenesis and tissue remodeling processes during CL formation, as well as in the tissue degradation during luteal regression. However, the absence of reproductive phenotypes in mice lacking uPA and several other matrix degrading proteases indicates that there are redundancies among different matrix degrading proteases or that tissue remodeling in the ovary may involve other additional unique elements.
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| 5. |
- Vaskivuo, Tommi E, et al.
(författare)
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Role of apoptosis, apoptosis-related factors and 17beta-hydroxysteroid dehydrogenases in human corpus luteum regression
- 2002
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Ingår i: Molecular and Cellular Endocrinology. - 0303-7207 .- 1872-8057. ; 194:1-2, s. 191-200
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Tidskriftsartikel (refereegranskat)abstract
- The human corpus luteum (CL) is a transient endocrine organ with a life span of 14-16 days. Apoptosis has been suggested to be the mechanism of CL regression and the possible regulatory role of the bcl-2 family in this process has been studied in animals and, to some extent, in humans. In the present study, apoptosis was studied in the human CL and in luteinised granulosa cells by in situ 3'-end labelling and gel electrophoretic DNA fragmentation analysis. The apoptosis-regulating factors Bcl-2, Bax and TNF-alpha, transcription factor NF-kappaB and Caspase-3, a key executioner protein in apoptotic cell death, were studied by immunohistochemistry and in situ hybridisation. Furthermore, we analysed expression of 17beta hydroxysteroid dehydrogenase (17HSD) type 1 and 2, key enzymes in the estrogen metabolism. Apoptosis was found in the CL throughout the luteal phase, but a marked increase of apoptotic luteal cells was observed during the late luteal phase (CL day 11-14). This was preceded by a clear increase of 17HSD type 1 expression. The apoptosis-regulating proteins Bcl-2 and Bax were expressed constantly in the CL throughout the luteal phase. TNF-alpha expression was constant during the early and mid-luteal phases, but in the late luteal phase, some specimens showed increased immunostaining. NF-kappaB and Caspase-3 were present in the CL throughout the luteal phase and in individual specimens, the expression of Caspase-3 was associated with a high rate of apoptosis in the late luteal phase. In conclusion, apoptosis is involved in human luteal regression and estradiol (E(2)) may function as a trigger for this process. The expression of the pro- and anti-apoptotic factors studied in the CL suggest their part in this process, but the conclusive evidence for the exact molecular mechanisms remains open.
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| 6. |
- Öberg-Welsh, Charlotte, et al.
(författare)
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Effects of vascular endothelial growth factor on pancreatic duct cell replication and the insulin production of fetal islet-like cell clusters in vitro
- 1997
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Ingår i: Molecular and Cellular Endocrinology. - 0303-7207 .- 1872-8057. ; 126:2, s. 125-132
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that the tyrosine kinase receptor Flk-1 and its ligand, vascular endothelial growth factor (VEGF), may play a role in the development of fetal rat islet-like structures in vitro, possibly by stimulating the maturation of endocrine precursor cells in the pancreatic ductal epithelium. In order to further assess this, adult rat pancreatic ducts and fetal porcine islet-like cell clusters (ICC) were cultured in the presence of VEGF. In ducts, VEGF stimulated the mitogenesis in the epithelium. Culture of ICC in the presence of VEGF significantly enhanced their insulin content, but decreased the insulin accumulation to the culture medium. Glucose-stimulated acute insulin release was not affected by VEGF. Northern blot analysis after partial pancreatectomy in adult rats revealed induction of VEGF mRNA 3 days after the operation. Immunohistochemistry of fetal rat pancreas showed staining mainly in the islets of Langerhans. We conclude that VEGF directly stimulates the replication of the ductal epithelium, a possible prerequisite for β-cell formation. This could require local production of VEGF, which may alter in response to physiological demands.
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| 7. |
- Andersson, Annika K., et al.
(författare)
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Cytokine-induced PGE2 formation is reduced from iNOS deficient murine islets
- 2004
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 220:1-2, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Cytokines may be involved in islet destruction during Type 1 diabetes. Exposure to interleukin-1beta (IL-1beta) or IL-1beta plus interferon-gamma (IFN-gamma) of rodent islets induces expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Subsequent formation of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) may impair beta-cell function. Using iNOS deficient (iNOS -/-) islets, we have further investigated the relation between NO formation and PGE(2) induction. We found that iNOS -/- islets responded with a reduced PGE(2) formation following IL-1beta or (IL-1beta + IFN-gamma) treatment compared to wild-type (wt) islets, while COX-2 mRNA or protein content were unchanged. By the addition of an NO donor together with IL-1beta, PGE(2) formation could be stimulated from iNOS -/- islets. We conclude that the lowered capacity of PGE(2) formation observed from cytokine exposed iNOS -/- islets is due to a decreased stimulation of PGE(2) formation by the COX-2 enzyme in the absence of NO, rather then differences in expressed COX-2 protein.
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| 8. |
- Andersson, Sofia A, et al.
(författare)
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Reduced insulin secretion correlates with decreased expression of exocytotic genes in pancreatic islets from patients with type 2 diabetes.
- 2012
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 1872-8057 .- 0303-7207. ; 364:1-2, s. 36-45
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Tidskriftsartikel (refereegranskat)abstract
- Reduced insulin release has been linked to defect exocytosis in β-cells. However, whether expression of genes suggested to be involved in the exocytotic process (exocytotic genes) is altered in pancreatic islets from patients with type 2 diabetes (T2D), and correlate to insulin secretion, needs to be further investigated. Analysing expression levels of 23 exocytotic genes using microarray revealed reduced expression of five genes in human T2D islets (χ(2)=13.25; p<0.001). Gene expression of STX1A, SYT4, SYT7, SYT11, SYT13, SNAP25 and STXBP1 correlated negatively to in vivo measurements of HbA1c levels and positively to glucose stimulated insulin secretion (GSIS) in vitro in human islets. STX1A, SYT4 and SYT11 protein levels correspondingly decreased in human T2D islets. Moreover, silencing of SYT4 and SYT13 reduced GSIS in INS1-832/13 cells. Our data support that reduced expression of exocytotic genes contributes to impaired insulin secretion, and suggest decreased expression of these genes as part of T2D pathogenesis.
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| 9. |
- Balhuizen, Alexander, et al.
(författare)
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Activation of G protein-coupled receptor 30 modulates hormone secretion and counteracts cytokine-induced apoptosis in pancreatic islets of female mice.
- 2010
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 1872-8057 .- 0303-7207. ; 320, s. 16-24
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Tidskriftsartikel (refereegranskat)abstract
- The role of the newly discovered estrogen receptor GPR30 in islet physiology and pathophysiology is unclear. We examined GPR30 expression in relation to hormone secretion and possible anti-apoptotic effects in isolated mouse islets using the synthetic GPR30 ligand G-1. The mRNA and protein expression of GPR30 was analyzed by qPCR, Western blot and confocal microscopy. Hormone secretion and cAMP content were determined with RIA and apoptosis in islet cells with the Annexin-V method. GPR30 mRNA and protein expression was markedly higher in islets from females compared to male. This gender difference was not found for the genomic estrogen receptors ERalpha and ERbeta, the ERalpha expression being 10-fold higher than ERbeta in both genders. Confocal microscopy revealed abounden GPR30 expression in insulin, glucagon and somatostatin cells. Dose-response studies of G-1 vs 17beta-estradiol in isolated islets at 1 or 12mM glucose showed an almost identical pattern in that both compounds increased insulin and inhibited glucagon and somatostatin secretion. ICI-182,780 and EM-652, potent antagonists of the 17beta-estradiol receptors (ERalpha and ERbeta) did not influence the amplifying effect of G-1 or 17beta-estradiol on cAMP content or insulin secretion from isolated islets. Cytokine-induced (IL-1beta+TNFalpha+INFgamma) apoptosis in islets, cultured for 24h at 5mM glucose, was almost abolished by G-1 or 17beta-estradiol treatment. Addition of ICI-182,780 or EM-652 did not affect this beneficial effect of G-1 or 17beta-estradiol. Taken together, our findings show that GPR30 is expressed in most islet endocrine cells. The synthetic GPR30 ligand G-1 mimics the non-genomic effects of 17beta-estradiol on islet hormone secretion, cAMP content in islets and its anti-apoptotic effects. G-1 or analogs thereof might be new potential candidates in the therapeutic strategy for type 2 diabetes in women.
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| 10. |
- Banerjee, Meenal, et al.
(författare)
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Proliferation and plasticity of human beta cells on physiologically occurring laminin isoforms
- 2012
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 355:1, s. 78-86
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Tidskriftsartikel (refereegranskat)abstract
- We have previously characterized the molecular composition of human islet basement membranes and shown that human beta cells bind to laminin 511 (LM511) through integrin alpha 3 beta 1 and Lutheran glycoprotein. We have now investigated the impact of physical contact between cultured human beta cells and the laminin isoforms occurring in their natural niche. Human islet preparations derived from 15 donors were used, beta cells and duct cells were purified by magnetic sorting. Overall beta-cell proliferation was low or undetectable. However, in many experiments the only proliferating beta cells were detected in contact with the laminin isoforms that are found in the human islets in vivo (511 and 411). Purified ductal and beta cells underwent epithelial-mesenchymal transition (EMT). LM511 partially blocked this dedifferentiation of purified beta cells, and did not affect purified duct cells. Interactions with the surrounding basement membrane are important for the growth and function of human beta cells. However, only a very limited level of beta-cell proliferation can be induced by exogenous factors. LM511 may be a useful substrate for human beta-cell maintenance in vitro.
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