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- Fagman, Henrik, 1975, et al.
(författare)
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Morphogenetics of early thyroid development.
- 2010
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Ingår i: Journal of molecular endocrinology. - 1479-6813.
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Forskningsöversikt (refereegranskat)abstract
- The thyroid develops from the foregut endoderm. Yet uncharacterized inductive signals specify endoderm progenitors to a thyroid cell fate that assemble in the pharyngeal floor from which the primordium buds and migrates to the final position of the gland. The morphogenetic process is regulated by both cell-autonomous (activated by e.g. Nkx2-1, Foxe1, Pax8 and Hhex) and mesoderm-derived (mediated by e.g. Tbx1 and Fgf) mechanisms acting in concert to promote growth and survival of progenitor cells. The developmental role of thyroid-stimulating hormone is limited to thyroid differentiation set to work after the gross anatomy of the gland is already sculptured. This review summarizes recent advances on the molecular genetics of thyroid morphogenesis put into context of endoderm developmental traits and highlights established and potentially novel mechanisms of thyroid dysgenesis of relevance to congenital hypothyroidism in man.
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| 6. |
- Fagman, Henrik, 1975, et al.
(författare)
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Morphogenetics of early thyroid development.
- 2011
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Ingår i: Journal of molecular endocrinology. - 1479-6813. ; 46:1
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Forskningsöversikt (refereegranskat)abstract
- The thyroid develops from the foregut endoderm. Yet uncharacterized inductive signals specify endoderm progenitors to a thyroid cell fate that assembles in the pharyngeal floor from which the primordium buds and migrates to the final position of the gland. The morphogenetic process is regulated by both cell-autonomous (e.g. activated by NKX2-1, FOXE1, PAX8, and HHEX) and mesoderm-derived (e.g. mediated by TBX1 and fibroblast growth factors) mechanisms acting in concert to promote growth and survival of progenitor cells. The developmental role of TSH is limited to thyroid differentiation set to work after the gross anatomy of the gland is already sculptured. This review summarizes recent advances on the molecular genetics of thyroid morphogenesis put into context of endoderm developmental traits and highlights established and novel mechanisms of thyroid dysgenesis of potential relevance to congenital hypothyroidism in man.
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| 7. |
- Fridmanis, Davids, et al.
(författare)
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Replacement of short segments within transmembrane domains of MC2R disrupts retention signal
- 2014
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Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 53:2, s. 201-215
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Tidskriftsartikel (refereegranskat)abstract
- The proteolysis of the pro-opiomelanocortin precursor results in the formation of melanocortins (MCs), a group of peptides that share the conserved -H-F-R-W- sequence, which acts as a pharmacophore for five subtypes of MC receptors (MCRs). MC type 2 receptor (MC2R; also known as ACTHR) is the most specialized of all the MCRs. It is predominantly expressed in the adrenal cortex and specifically binds ACTH. Unlike other MCRs, it requires melanocortin receptor accessory protein 1 (MRAP) for formation of active receptor and for its transport to the cell membrane. The molecular mechanisms underlying this specificity remain poorly understood. In this study, we used directed mutagenesis to investigate the role of various short MC2R sequence segments in receptor membrane trafficking and specific activation upon stimulation with ligands. The strategy of the study was to replace two to five amino acid residues within one MC2R segment with the corresponding residues of MC4R. In total, 20 recombinant receptors C-terminally fused to enhanced green fluorescent protein were generated and their membrane trafficking efficiencies and cAMP response upon stimulation with α-MSH and ACTH(1-24) were estimated during their stand-alone expression and coexpression with MRAP. Our results indicate that both the motif that determines the ligand-recognition specificity and the intracellular retention signal are formed by a specific extracellular structure, which is supported by the correct alignment of the transmembrane domains. Our results also indicate that the aromatic-residue-rich segment of the second extracellular loop is involved in the effects mediated by the second ACTH pharmacophore (-K-K-R-R-).
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| 8. |
- Giandomenico, Valeria, et al.
(författare)
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Olfactory Receptor 51E1 as a Novel Target for Diagnosis in Somatostatin Receptor Negative Lung Carcinoids
- 2013
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Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 51, s. 277-286
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Tidskriftsartikel (refereegranskat)abstract
- Somatostatin receptors (SSTRs) may be used in lung carcinoids (LCs) for diagnosis and therapy, although additional targets are clearly warranted. This study aimed to investigate whether olfactory receptor 51E1 (OR51E1) may be a potential target for LCs. OR51E1 coding sequence was analyzed in LC cell lines, NCI-H727 and NCI-H720. OR51E1 transcript expression was investigated in LC cell lines and frozen specimens by quantitative real-time PCR. OR51E1, SSTR2, SSTR3, and SSTR5 expression was evaluated by immunohistochemistry on paraffin-embedded sections of 73 typical carcinoids (TCs), 14 atypical carcinoids (ACs) and 11 regional/distant metastases, and compared to OctreoScan data. Immunohistochemistry results were rendered semiquantitatively on a scale from 0 to 3+, taking into account the cellular compartmentalization (membrane vs. cytoplasm) and the percentage of tumor cells (<50% vs. >50%). Our results showed that wild-type OR51E1 transcript was expressed in both LC cell lines. OR51E1 mRNA was expressed in 9/12 TCs and 7/9 ACs (p=NS). Immunohistochemically, OR51E1, SSTR2, SSTR3 and SSTR5 were detected in 85%, 71%, 25% and 39% of TCs, and in 86%, 79%, 43% and 36% of ACs, respectively. OR51E1 immunohistochemical scores were higher or equal compared to SSTRs in 79% of TCs and 86% of ACs. Furthermore, in the LC cases where all SSTR subtypes were lacking, membrane OR51E1 expression was detected in 10/17 TCs and 1/2 ACs. Moreover, higher OR51E1 immunohistochemical scores were detected in 5/6 OctreoScan-negative LC lesions. Therefore, the high expression of OR51E1 in LCs makes it a potential novel diagnostic target in SSTR-negative tumors.
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| 9. |
- Gormand, Amelie, et al.
(författare)
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LKB1 signalling attenuates early events of adipogenesis and responds to adipogenic cues.
- 2014
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Ingår i: Journal of Molecular Endocrinology. - 1479-6813. ; 53:1, s. 117-130
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Tidskriftsartikel (refereegranskat)abstract
- cAMP-response element-binding protein (CREB) is required for the induction of adipogenic transcription factors such as CCAAT/enhancer-binding proteins (C/EBPs). Interestingly, it is known from other tissues that LKB1 and its substrates AMP-activated protein kinase (AMPK) and salt-inducible kinases (SIKs), negatively regulate gene expression by phosphorylating the CREB co-activator CRTC2 and class IIa histone deacetylases (HDACs), which results in their exclusion from the nucleus where they co-activate or inhibit their targets. In this study, we show that AMPK/SIK signalling is acutely attenuated during adipogenic differentiation of 3T3-L1 preadipocytes, which coincides with dephosphorylation and nuclear translocation of CRTC2 and HDAC4. When subjected to differentiation, 3T3-L1 preadipocytes in which LKB1 expression was stably reduced using shRNA (LKB1-shRNA), as well as LKB1 knockout mouse embryonic fibroblasts (LKB1-/- MEFs), differentiated more readily into adipocyte-like cells and accumulated more triglycerides compared to scrambled-shRNA 3T3-L1 cells or Wt MEFs. In addition, the phosphorylation of CRTC2 and HDAC4 was reduced, and the mRNA expression of adipogenic transcription factors C/EBPα, peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte-specific proteins such as hormone sensitive lipase (HSL), fatty acid synthase (FAS), aP2, Glut4 and adiponectin was increased in the absence of LKB1. The mRNA and protein expression of CHOP-10, a dominant negative member of the C/EBP family, was reduced in LKB1 shRNA expressing cells, providing a potential mechanism for the up-regulation of Pparg and Cebpa. These results support the hypothesis that LKB1 signalling keeps preadipocytes in their non-differentiated form.
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- Karger, Stefan, et al.
(författare)
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Distinct pattern of oxidative DNA damage and DNA repair in follicular thyroid tumours.
- 2012
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Ingår i: Journal of molecular endocrinology. - 1479-6813. ; 48:3, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- Increased oxidative stress has been linked to thyroid carcinogenesis. In this paper, we investigate whether oxidative DNA damage and DNA repair differ in follicular adenoma (FA) and follicular thyroid carcinoma (FTC). 7,8-Dihydro-8-oxoguanine (8-OxoG) formation was analysed by immunohistochemistry in 46 FAs, 52 FTCs and 18 normal thyroid tissues (NTs). mRNA expression of DNA repair genes OGG1, Mut Y homologue (MUTYH) and endonuclease III (NTHL1) was analysed by real-time PCR in 19 FAs, 25 FTCs and 19 NTs. Induction and repair of oxidative DNA damage were studied in rat FRTL-5 cells after u.v. irradiation. Moreover, activation of DNA damage checkpoints (ataxia telangiectasia mutated (ATM) and H2A histone family, member X (H2AFX (H2AFX))) and proliferation index (MIB-1) were quantified in 28 non-oxyphilic and 24 oxyphilic FTCs. Increased nuclear and cytosolic 8-OxoG formation was detected in FTC compared with follicular adenoma, whereby cytosolic 8-OxoG formation was found to reflect RNA oxidation. Significant downregulation of DNA repair enzymes was detected in FTC compared with FA. In vitro experiments mirrored the findings in FTC with oxidative stress-induced DNA checkpoint activation and downregulation of OGG1, MUTYH and NTHL1 in FRTL-5 cells, an effect that, however, was reversible after 24 h. Further analysis of FTC variants showed decreased oxidative DNA damage, sustained checkpoint activation and decreased proliferation in oxyphilic vs non-oxyphilic FTC. Our data suggest a pathophysiological scenario of accumulating unrepaired DNA/RNA damage in FTC vs counterbalanced DNA/RNA damage and repair in FA. Furthermore, this study provides the first evidence for differences in oxidative stress defence in FTC variants with possible implications for therapeutic response and prognostic outcome.
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| 12. |
- Lenhart, P.M., et al.
(författare)
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G-protein-coupled receptor 30 interacts with receptor activity-modifying protein 3 and confers sex-dependent cardioprotection
- 2013
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Ingår i: Journal of Molecular Endocrinology. - 1479-6813. ; 51:1, s. 191-202
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Receptor activity-modifying protein 3 (RAMP3) is a single-pass transmembrane protein known to interact with and affect the trafficking of several G-protein-coupled receptors (GPCRs). We sought to determine whether RAMP3 interacts with GPR30, also known as G-protein-coupled estrogen receptor 1. GPR30 is a GPCR that binds estradiol and has important roles in cardiovascular and endocrine physiology. Using bioluminescence resonance energy transfer titration studies, co-immunoprecipitation, and confocal microscopy, we show that GPR30 and RAMP3 interact. Furthermore, the presence of GPR30 leads to increased expression of RAMP3 at the plasma membrane in HEK293 cells. In vivo, there are marked sex differences in the subcellular localization of GPR30 in cardiac cells, and the hearts of Ramp3(-/-) mice also show signs of GPR30 mislocalization. To determine whether this interaction might play a role in cardiovascular disease, we treated Ramp3(+)(/)(+) and Ramp3(-/-) mice on a heart disease-prone genetic background with G-1, a specific agonist for GPR30. Importantly, this in vivo activation of GPR30 resulted in a significant reduction in cardiac hypertrophy and perivascular fibrosis that is both RAMP3 and sex dependent. Our results demonstrate that GPR30-RAMP3 interaction has functional consequences on the localization of these proteins both in vitro and in vivo and that RAMP3 is required for GPR30-mediated cardioprotection.
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| 13. |
- Lu, Ming, et al.
(författare)
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Expression and association of TRPC subtypes with Orai1 and STIM1 in human parathyroid
- 2010
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Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 44:5, s. 285-294
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism behind Ca2+ entry into the parathyroid cells has been widely debated, and the molecular identities of the responsible ion channels have not been established yet. In this study, we show that the parathyroid cells lack voltage-operated Ca2+ channels. Passive store depletion by thapsigargin, on the other hand, induces a large non-voltage-activated non-selective cation current. The increase in intracellular Ca2+ caused by thapsigargin is attenuated by 2-aminoethoxydiphenyl borate, a blocker of store-operated Ca2+ entry (SOCE). Candidate molecules for non-voltage-operated Ca2+ signaling were investigated. These included members of the transient receptor potential canonical (TRPC) ion channel family, as well as Ca2+ release-activated Ca2+ modulator 1 (Orai1) and stromal interaction molecule 1 (STIM1) that are key proteins in the SOCE pathway. Using RT-PCR screening, quantitative real-time PCR, and western blot, we showed expression of TRPC1, TRPC4, and TRPC6; Orai1; and STIM1 genes and proteins in normal and adenomatous human parathyroid tissues. Furthermore, co-immunoprecipitation experiments demonstrated a ternary complex of TRPC1-Orai1-STIM1, supporting a physical interaction between these molecules in human parathyroid.
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- Svensson, Johan, 1964, et al.
(författare)
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Stimulation of both estrogen and androgen receptors maintains skeletal muscle mass in gonadectomized male mice but mainly via different pathways.
- 2010
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Ingår i: Journal of molecular endocrinology. - 1479-6813. ; 45:1, s. 45-57
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Tidskriftsartikel (refereegranskat)abstract
- Testosterone is a major regulator of muscle mass. Little is known whether this is due to a direct stimulation of the androgen receptor (AR) or mediated by aromatization of testosterone to estradiol (E(2)), the ligand for the estrogen receptors (ERs), in peripheral tissues. In this study, we differentiated between the effects mediated by AR and ER by treating orchidectomized (orx) male mice for 5 weeks with E(2) or the non-aromatizable androgen dihydrotestosterone (DHT). Both E(2) and DHT increased muscle weight and lean mass, although the effect was less marked after E(2) treatment. Studies of underlying mechanisms were performed using gene transcript profiling (microarray and real-time PCR) in skeletal muscle, and they demonstrated that E(2) regulated 51 genes and DHT regulated 187 genes, with 13 genes (=25% of E(2)-regulated genes) being regulated by both treatments. Both E(2) and DHT altered the expression of Fbxo32, a gene involved in skeletal muscle atrophy, affected the IGF1 system, and regulated genes involved in angiogenesis and the glutathione metabolic process. Only E(2) affected genes that regulate intermediary glucose and lipid metabolism, and only DHT increased the expression of genes involved in synaptic transmission and heme and polyamine biosynthesis. In summary, ER activation by E(2) treatment maintains skeletal muscle mass after orx. This effect is less marked than that of AR activation by DHT treatment, which completely prevented the effect of orx on muscle mass and was partly, but not fully, mediated via alternative pathways.
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| 18. |
- Tostivint, Hervé, et al.
(författare)
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Molecular evolution of GPCRS: : somatostatin/urotensin II receptors
- 2014
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Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 52, s. T61-86
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Tidskriftsartikel (refereegranskat)abstract
- Somatostatin (SS) and urotensin II (UII) are members of two families of structurally related neuropeptides present in all vertebrates. They exert a large array of biological activities that are mediated by two families of G-protein-coupled receptors called SSTR and UTS2R respectively. It is proposed that the two families of peptides as well as those of their receptors probably derive from a single ancestral ligand-receptor pair. This pair had already been duplicated before the emergence of vertebrates to generate one SS peptide with two receptors and one UII peptide with one receptor. Thereafter, each family expanded in the three whole-genome duplications (1R, 2R, and 3R) that occurred during the evolution of vertebrates, whereupon some local duplications and gene losses occurred. Following the 2R event, the vertebrate ancestor is deduced to have possessed three SS (SS1, SS2, and SS5) and six SSTR (SSTR1-6) genes, on the one hand, and four UII (UII, URP, URP1, and URP2) and five UTS2R (UTS2R1-5) genes, on the other hand. In the teleost lineage, all these have been preserved with the exception of SSTR4. Moreover, several additional genes have been gained through the 3R event, such as SS4 and a second copy of the UII, SSTR2, SSTR3, and SSTR5 genes, and through local duplications, such as SS3. In mammals, all the genes of the SSTR family have been preserved, with the exception of SSTR6. In contrast, for the other families, extensive gene losses occurred, as only the SS1, SS2, UII, and URP genes and one UTS2R gene are still present.
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| 19. |
- Vikman, Petter, et al.
(författare)
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RNA sequencing: current and prospective uses in metabolic research.
- 2014
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Ingår i: Journal of Molecular Endocrinology. - 1479-6813. ; 53:2, s. 93-101
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Forskningsöversikt (refereegranskat)abstract
- Previous global RNA analysis was restricted to known transcripts in species with a defined transcriptome. Next generation sequencing has transformed transcriptomics by making it possible to analyse expressed genes with an exon level resolution from any tissue in any species without any a priori knowledge of which genes that are being expressed, splice patterns or their nucleotide sequence. In addition, RNA sequencing is a more sensitive technique compared with microarrays with a larger dynamic range, and it also allows for investigation of imprinting and allele-specific expression. This can be done for a cost that is able to compete with that of a microarray, making RNA sequencing a technique available to most researchers. Therefore RNA sequencing has recently become the state of the art with regards to large-scale RNA investigations and has to a large extent replaced microarrays. The only drawback is the large data amounts produced, which together with the complexity of the data can make a researcher spend far more time on analysis than performing the actual experiment.
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- Wierup, Nils, et al.
(författare)
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The islet ghrelin cell.
- 2014
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Ingår i: Journal of Molecular Endocrinology. - 1479-6813. ; 52:1, s. 35-49
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Forskningsöversikt (refereegranskat)abstract
- The islets of Langerhans are key regulators of glucose homeostasis and have been known as a structure for almost one and a half centurys now. During the twentieth century several different cell types were described in the islets of different species and at different developmental stages. Six cell types with identified hormonal product have been described so far by the use of histochemical staining methods, transmission electron microscopy, and immunohistochemistry. Thus, glucagon-producing alpha-cells, insulin-producing beta-cells, somatostatin-producing delta-cells, pancreatic polypeptide-producing PP-cells, Serotonin-producing EC-cells, and gastrin-producing G-cells have all been found in the mammalian pancreas at least at some developmental stage. Species differences are at hand and age-related differences are also to be considered. Eleven years ago a novel cell type, the ghrelin cell, was discovered in the human islets. Subsequent studies have shown the presence of islet ghrelin cells in several animals, including mouse, rat, gerbils, and fish. The developmental regulation of ghrelin cells in the islets of mice has gained a lot of interest and several studies have added important pieces to the puzzle of molecular mechanisms and the genetic regulation that lead to differentiation into mature ghrelin cells. A body of evidence has shown that ghrelin is an insulinostatic hormone, and the potential for blockade of ghrelin signalling as a therapeutic avenue for type 2 diabetes is intriguing. Furthermore, ghrelin expressing pancreatic tumours have been reported and ghrelin needs to be taken into account when diagnosing pancreatic tumours. In this review article we summarize the knowledge about islet ghrelin cells obtained so far.
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