scholarly journals 11β-Hydroxysteroid dehydrogenase and the pre-receptor regulation of corticosteroid hormone action

2005 ◽  
Vol 186 (2) ◽  
pp. 251-271 ◽  
Author(s):  
Nicole Draper ◽  
Paul M Stewart
Keyword(s):  
Molecular Basis ◽  
Hydroxysteroid Dehydrogenase ◽  
Hormone Action ◽  
Enzyme Expression ◽  
Human Obesity ◽  
Corticosteroid Hormone

Two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD1 and 11β-HSD2) catalyse the interconversion of hormonally active cortisol and inactive cortisone. The enzyme evolved from a metabolic pathway to a novel mechanism underpinning human disease with the elucidation of the role of the type 2 or ‘kidney’ isozyme and an inherited form of hypertension, ‘apparent mineralocorti-coid excess’. ‘Cushing’s disease of the kidney’ arises because of a failure of 11β-HSD2 to inactivate cortisol to cortisone resulting in cortisol-induced mineralocorticoid excess. Conversely, 11β-HSD1 has been linked to human obesity and insulin resistance, but also to other diseases in which glucocorticoids have historically been implicated (osteoporosis, glaucoma). Here, the activation of cortisol from cortisone facilitates glucocorticoid hormone action at an autocrine level. The molecular basis for the putative human 11β-HSD1 ‘knockout’ – ‘cortisone reductase deficiency’ - has recently been described, an observation that also answers a long standing conundrum relating to the set-point of 11β-HSD1 activity. In each case, these clinical studies have been underpinned by studies in vitro and the manipulation of enzyme expression in vivo using recombinant mouse models.

Intracellular regulation of 17β-hydroxysteroid dehydrogenase type 2 catalytic activity in A431 cells

1997 ◽  
Vol 153 (3) ◽  
pp. 453-464 ◽  
Author(s):  
C H Blomquist ◽  
B S Leung ◽  
C Beaudoin ◽  
D Poirier ◽  
Y Tremblay
Keyword(s):  
Reductase Activity ◽  
Maximum Velocity ◽  
Hydroxysteroid Dehydrogenase ◽  
A431 Cells ◽  
Intact Cells ◽  
Cell Monolayers ◽  
Intracellular Regulation

Abstract There is growing evidence that various isoforms of 17β-hydroxysteroid dehydrogenase (17-HSD) are regulated at the level of catalysis in intact cells. A number of investigators have proposed that the NAD(P)/NAD(P)H ratio may control the direction of reaction. In a previous study, we obtained evidence that A431 cells, derived from an epidermoid carcinoma of the vulva, are enriched in 17-HSD type 2, a membrane-bound isoform reactive with C18 and C19 17β-hydroxysteroids and 17-ketosteroids. The present investigation was undertaken to confirm the presence of 17-HSD type 2 in A431 cells and to assess intracellular regulation of 17-HSD at the level of catalysis by comparing the activity of homogenates and microsomes with that of cell monolayers. Northern blot analysis confirmed the presence of 17-HSD type 2 mRNA. Exposure of cells to epidermal growth factor resulted in an increase in type 2 mRNA and, for microsomes, increases in maximum velocity (Vmax) with no change in Michaelis constant (Km) for testosterone and androstenedione, resulting in equivalent increases in the Vmax/Km ratio consistent with the presence of a single enzyme. Initial velocity data and inhibition patterns were consistent with a highly ordered reaction sequence in vitro in which testosterone and androstenedione bind only to either an enzyme–NAD or an enzyme–NADH complex respectively. Microsomal dehydrogenase activity with testosterone was 2- to 3-fold higher than reductase activity with androstenedione. In contrast, although cell monolayers rapidly converted testosterone to androstenedione, reductase activity with androstenedione or dehydroepiandrosterone (DHEA) was barely detectable. Lactate but not glucose, pyruvate or isocitrate stimulated the conversion of androstenedione to testosterone by monolayers, suggesting that cytoplasmic NADH may be the cofactor for 17-HSD type 2 reductase activity with androstenedione. However, exposure to lactate did not result in a significant change in the NAD/NADH ratio of cell monolayers. It appears that within A431 cells 17-HSD type 2 is regulated at the level of catalysis to function almost exclusively as a dehydrogenase. These findings give further support to the concept that 17-HSD type 2 functions in vivo principally as a dehydrogenase and that its role as a reductase in testosterone formation by either the Δ4 or Δ5 pathway is limited. Journal of Endocrinology (1997) 153, 453–464

scholarly journals PPARδActivity in Cardiovascular Diseases: A Potential Pharmacological Target

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Angela Tesse ◽  
Ramaroson Andriantsitohaina ◽  
Thierry Ragot
Keyword(s):  
Metabolic Diseases ◽  
Peroxisome Proliferator ◽  
In Vivo Models ◽  
Pharmacological Target ◽  
Cardiovascular Cells ◽  
Peroxisome Proliferator Activated Receptors

Activation of peroxisome proliferator-activated receptors (PPARs), and particularly of PPARαand PPARγ, using selective agonists, is currently used in the treatment of metabolic diseases such as hypertriglyceridemia and type 2 diabetes mellitus. PPARαand PPARγanti-inflammatory, antiproliferative and antiangiogenic properties in cardiovascular cells were extensively clarified in a variety of in vitro and in vivo models. In contrast, the role of PPARδin cardiovascular system is poorly understood. Prostacyclin, the predominant prostanoid released by vascular cells, is a putative endogenous agonist for PPARδ, but only recently PPARδselective synthetic agonists were found, improving studies about the physiological and pathophysiological roles of PPARδactivation. Recent reports suggest that the PPARδactivation may play a pivotal role to regulate inflammation, apoptosis, and cell proliferation, suggesting that this transcriptional factor could become an interesting pharmacological target to regulate cardiovascular cell apoptosis, proliferation, inflammation, and metabolism.

scholarly journals Central role of autophagic UVRAG in melanogenesis and the suntan response

2018 ◽  
Vol 115 (33) ◽  
pp. E7728-E7737 ◽  
Author(s):  
Yongfei Yang ◽  
Gyu-beom Jang ◽  
Xuanjun Yang ◽  
Qiaoxiu Wang ◽  
Shanshan He ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Transcriptional Factor ◽  
Exposed Skin ◽  
Skin Cancers ◽  
Integral Role ◽  
Direct Target ◽  
Lysosome Related Organelles

UV-induced cell pigmentation represents an important mechanism against skin cancers. Sun-exposed skin secretes α-MSH, which induces the lineage-specific transcriptional factor MITF and activates melanogenesis in melanocytes. Here, we show that the autophagic tumor suppressor UVRAG plays an integral role in melanogenesis by interaction with the biogenesis of lysosome-related organelles complex 1 (BLOC-1). This interaction is required for BLOC-1 stability and for BLOC-1–mediated cargo sorting and delivery to melanosomes. Absence of UVRAG dispersed BLOC-1 distribution and activity, resulting in impaired melanogenesis in vitro and defective melanocyte development in zebrafish in vivo. Furthermore, our results establish UVRAG as an important effector for melanocytes’ response to α-MSH signaling as a direct target of MITF and reveal the molecular basis underlying the association between oncogenic BRAF and compromised UV protection in melanoma.

scholarly journals Strain-Specific Regulatory Role of Eukaryote-Like Serine/Threonine Phosphatase in Pneumococcal Adherence

2012 ◽  
Vol 80 (4) ◽  
pp. 1361-1372 ◽  
Author(s):  
Shivangi Agarwal ◽  
Shivani Agarwal ◽  
Preeti Pancholi ◽  
Vijay Pancholi
Keyword(s):  
High Efficiency ◽  
Regulatory System ◽  
Gene Encoding ◽  
Content Type ◽  
Knockout Mutants ◽  
Catalytically Active

ABSTRACTStreptococcus pneumoniaeexploits a battery of virulence factors to colonize the host. Although the eukaryote-like Ser/Thr kinase ofS. pneumoniae(StkP) has been implicated in physiology and virulence, the role of its cotranscribing phosphatase (PhpP) has remained elusive. The construction of nonpolar markerlessphpPknockout mutants (ΔphpP) in two pathogenic strains, D39 (type 2) and 6A-EF3114 (type 6A), indicated that PhpP is not indispensable for pneumococcal survival. Further, PhpP also participates in the regulation of cell wall biosynthesis/division, adherence, and biofilm formation in a strain-specific manner. Additionally, we provide hitherto-unknownin vitroandin vivoevidence of a physiologically relevant biochemical link between the StkP/PhpP-mediated cognate regulation and the two-component regulatory system TCS06 (RR06/HK06) that regulates the expression of the gene encoding an important pneumococcal surface adhesin, CbpA, which was found to be significantly upregulated in ΔphpPmutants. In particular, StkP (threonine)-phosphorylated RR06 bound to thecbpApromoter with high efficiency even in the absence of the HK06-responsive and catalytically active aspartate 51 residue. Together, our findings unravel the significant contributions of PhpP in pneumococcal physiology and adherence.

scholarly journals HPA axis changes during the initial phase of psychosocial stressor exposure in male mice

2013 ◽  
Vol 218 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Nicole Uschold-Schmidt ◽  
Daniel Peterlik ◽  
Andrea M Füchsl ◽  
Stefan O Reber
Keyword(s):  
Initial Phase ◽  
Adrenal Mass ◽  
Plasma Acth ◽  
Steroidogenic Enzyme ◽  
Pronounced Increase ◽  
Basal Plasma

Chronic subordinate colony (CSC) housing for 19 days results in unaffected basal morning corticosterone (CORT) levels despite a pronounced increase in adrenal mass, likely mediated by an attenuation of adrenal corticotropin (ACTH) responsiveness. Given that the pronounced increase in basal morning plasma CORT levels returns to baseline as early as 48 h after the start of CSC, it is likely that the attenuated ACTH responsiveness develops already during this initial phase. This was tested in the present study. In line with previous findings, basal morning plasma CORT levels were elevated following 10 h, but not 48 h, of CSC exposure. Basal morning plasma ACTH concentrations and relative in vivo adrenal CORT content were increased following 10 h and to a lesser extent following 48 h of CSC exposure, positively correlating. Relative in vitro adrenal CORT secretion in response to ACTH (100 nM) and kidney protein expression of 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) were unaffected following both time points. Adrenal mRNA expression of key steroidogenic enzymes was unaffected/decreased following 10 h and unaffected/increased following 48 h of CSC exposure. Together, our findings suggest that basal plasma hypercorticism during the initial CSC phase is mainly prevented by an attenuation of pituitary ACTH release. An increased absolute adrenal weight following 10 h, but not 48 h, of CSC exposure indicates that restoration of normal adrenal mass also adds to a lesser extent to prevent basal hypercorticism. A contributing role of alterations in enzymatic CORT degradation and steroidogenic enzyme availability is likely, but has to be further addressed in future studies.

scholarly journals Functional Role of miR-155 in the Pathogenesis of Diabetes Mellitus and Its Complications

2021 ◽  
Vol 7 (3) ◽  
pp. 39
Author(s):  
Stanislovas S. Jankauskas ◽  
Jessica Gambardella ◽  
Celestino Sardu ◽  
Angela Lombardi ◽  
Gaetano Santulli
Keyword(s):  
Diabetes Mellitus ◽  
Metabolic Stress ◽  
Serum Levels ◽  
In Vitro Models ◽  
Preclinical Studies

Substantial evidence indicates that microRNA-155 (miR-155) plays a crucial role in the pathogenesis of diabetes mellitus (DM) and its complications. A number of clinical studies reported low serum levels of miR-155 in patients with type 2 diabetes (T2D). Preclinical studies revealed that miR-155 partakes in the phenotypic switch of cells within the islets of Langerhans under metabolic stress. Moreover, miR-155 was shown to regulate insulin sensitivity in liver, adipose tissue, and skeletal muscle. Dysregulation of miR-155 expression was also shown to predict the development of nephropathy, neuropathy, and retinopathy in DM. Here, we systematically describe the reports investigating the role of miR-155 in DM and its complications. We also discuss the recent results from in vivo and in vitro models of type 1 diabetes (T1D) and T2D, discussing the differences between clinical and preclinical studies and shedding light on the molecular pathways mediated by miR-155 in different tissues affected by DM.

scholarly journals Mesenchymal stromal cells attenuate alveolar type 2 cells senescence through regulating NAMPT-mediated NAD metabolism

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaofan Lai ◽  
Shaojie Huang ◽  
Sijia Lin ◽  
Lvya Pu ◽  
Yaqing Wang ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Therapeutic Potential ◽  
Alveolar Type ◽  
Therapeutic Effects ◽  
Protective Effects ◽  
Nad Metabolism

Abstract Background Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive deadly fibrotic lung disease with high prevalence and mortality worldwide. The therapeutic potential of mesenchymal stem cells (MSCs) in pulmonary fibrosis may be attributed to the strong paracrine, anti-inflammatory, anti-apoptosis and immunoregulatory effects. However, the mechanisms underlying the therapeutic effects of MSCs in IPF, especially in terms of alveolar type 2 (AT2) cells senescence, are not well understood. The purpose of this study was to evaluate the role of MSCs in NAD metabolism and senescence of AT2 cells in vitro and in vivo. Methods MSCs were isolated from human bone marrow. The protective effects of MSCs injection in pulmonary fibrosis were assessed via bleomycin mouse models. The senescence of AT2 cells co-cultured with MSCs was evaluated by SA-β-galactosidase assay, immunofluorescence staining and Western blotting. NAD+ level and NAMPT expression in AT2 cells affected by MSCs were determined in vitro and in vivo. FK866 and NAMPT shRNA vectors were used to determine the role of NAMPT in MSCs inhibiting AT2 cells senescence. Results We proved that MSCs attenuate bleomycin-induced pulmonary fibrosis in mice. Senescence of AT2 cells was alleviated in MSCs-treated pulmonary fibrosis mice and when co-cultured with MSCs in vitro. Mechanistic studies showed that NAD+ and NAMPT levels were rescued in AT2 cells co-cultured with MSCs and MSCs could suppress AT2 cells senescence mainly via suppressing lysosome-mediated NAMPT degradation. Conclusions MSCs attenuate AT2 cells senescence by upregulating NAMPT expression and NAD+ levels, thus exerting protective effects in pulmonary fibrosis.

Abstract P124: Human Small Artery MicroRNA Expression Profiles: Changes in Type 2 Diabetes and Associations with Endothelial Function

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
David M Jensen ◽  
Michael E Widlansky ◽  
Chen Chu ◽  
Pengyuan Liu ◽  
Yong Liu ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Mirna Expression ◽  
Differentially Expressed ◽  
Microvascular Endothelium ◽  
Small Arteries ◽  
Type 2 Dm

Background: Studies of experimental models and human blood samples support an important role of microRNAs (miRNAs) in the development of vascular dysfunction in hypertension and diabetes mellitus (DM). Information on miRNA expression in clinically directly relevant tissues such as human small arteries and its relationship with impaired vascular endothelial function is currently lacking. Methods and Results: 38 subjects (18 type 2 DM, 20 controls) underwent gluteal adipose pad biopsy to obtain small arteries for miRNA expression profiling by small RNA deep sequencing. In vivo conduit artery endothelial function was measured by brachial artery reactivity. In vitro microvascular endothelium dependent vasodilation was measured by videomicroscopy. Correlations between miRNA expression and measurements of endothelial function were calculated using generalized linear models. Several miRNAs correlated with measurements of vascular structure and function. Endothelium dependent vasodilation was impaired in type 2 DM subjects compared to controls based on both the vasodilatory response to peak dose acetylcholine (44±25 vs. 69±18 %, P=0.04) and by analyses of the entire acetylcholine dose-response curve. Several miRNAs were differentially expressed in small arteries from type 2 DM subjects, two of which were verified by real-time PCR. Cross-referencing the top 30 miRNAs (P<0.015) with prior studies of plasma miRNA expression in DM subjects identified 7 miRNAs differentially expressed in both human small arteries and plasma, all of which have some reported role in vascular regulation. Conclusions: Multiple miRNAs are differentially expressed in human small arteries in DM patients and correlated with in vivo or in vitro measurements of endothelial function, suggesting an important role of microvascular miRNAs in the development of endothelial dysfunction in humans.

scholarly journals Importance of group X–secreted phospholipase A2 in allergen-induced airway inflammation and remodeling in a mouse asthma model

2007 ◽  
Vol 204 (4) ◽  
pp. 865-877 ◽  
Author(s):  
William R. Henderson ◽  
Emil Y. Chi ◽  
James G. Bollinger ◽  
Ying-tzang Tien ◽  
Xin Ye ◽  
...  
Keyword(s):  
Airway Inflammation ◽  
Asthma Model ◽  
Acid Metabolites ◽  
Cytosolic Pla2 ◽  
Subepithelial Fibrosis ◽  
Goblet Cell Metaplasia

Arachidonic acid metabolites, the eicosanoids, are key mediators of allergen-induced airway inflammation and remodeling in asthma. The availability of free arachidonate in cells for subsequent eicosanoid biosynthesis is controlled by phospholipase A2s (PLA2s), most notably cytosolic PLA2-α. 10 secreted PLA2s (sPLA2s) have also been identified, but their function in eicosanoid generation is poorly understood. We investigated the role of group X sPLA2 (sPLA2-X), the sPLA2 with the highest in vitro cellular phospholipolysis activity, in acute and chronic mouse asthma models in vivo. The lungs of sPLA2-X−/− mice, compared with those of sPLA2-X+/+ littermates, had significant reduction in ovalbumin-induced infiltration by CD4+ and CD8+ T cells and eosinophils, goblet cell metaplasia, smooth muscle cell layer thickening, subepithelial fibrosis, and levels of T helper type 2 cell cytokines and eicosanoids. These data direct attention to sPLA2-X as a novel therapeutic target for asthma.

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