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Abstract
A critique of the literature that androgen deficit underlies women's sexual dysfunctions is provided. Although there is scant evidence that androgens are responsible, many aspects of androgen activity remain to be investigated. Research does link serum levels of dehydroepiandrosterone (DHEA) to women's sexual desire but apparently not via DHEA's androgenic activity. Current assessment and management of women's sexual dysfunction are summarized.
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Affiliation(s)
- Rosemary Basson
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada.
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2
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Labandeira-Garcia JL, Valenzuela R, Costa-Besada MA, Villar-Cheda B, Rodriguez-Perez AI. The intracellular renin-angiotensin system: Friend or foe. Some light from the dopaminergic neurons. Prog Neurobiol 2020; 199:101919. [PMID: 33039415 PMCID: PMC7543790 DOI: 10.1016/j.pneurobio.2020.101919] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 08/20/2020] [Accepted: 10/04/2020] [Indexed: 12/11/2022]
Abstract
The renin-angiotensin system (RAS) is one of the oldest hormone systems in vertebrate phylogeny. RAS was initially related to regulation of blood pressure and sodium and water homeostasis. However, local or paracrine RAS were later identified in many tissues, including brain, and play a major role in their physiology and pathophysiology. In addition, a major component, ACE2, is the entry receptor for SARS-CoV-2. Overactivation of tissue RAS leads several oxidative stress and inflammatory processes involved in aging-related degenerative changes. In addition, a third level of RAS, the intracellular or intracrine RAS (iRAS), with still unclear functions, has been observed. The possible interaction between the intracellular and extracellular RAS, and particularly the possible deleterious or beneficial effects of the iRAS activation are controversial. The dopaminergic system is particularly interesting to investigate the RAS as important functional interactions between dopamine and RAS have been observed in the brain and several peripheral tissues. Our recent observations in mitochondria and nucleus of dopaminergic neurons may clarify the role of the iRAS. This may be important for the developing of new therapeutic strategies, since the effects on both extracellular and intracellular RAS must be taken into account, and perhaps better understanding of COVID-19 cell mechanisms.
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Affiliation(s)
- Jose L Labandeira-Garcia
- Laboratory of Cellular and Molecular Neurobiology of Parkinson's Disease, Research Center for Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CiberNed), Madrid, Spain.
| | - Rita Valenzuela
- Laboratory of Cellular and Molecular Neurobiology of Parkinson's Disease, Research Center for Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CiberNed), Madrid, Spain
| | - Maria A Costa-Besada
- Laboratory of Cellular and Molecular Neurobiology of Parkinson's Disease, Research Center for Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CiberNed), Madrid, Spain
| | - Begoña Villar-Cheda
- Laboratory of Cellular and Molecular Neurobiology of Parkinson's Disease, Research Center for Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CiberNed), Madrid, Spain
| | - Ana I Rodriguez-Perez
- Laboratory of Cellular and Molecular Neurobiology of Parkinson's Disease, Research Center for Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CiberNed), Madrid, Spain
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3
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Abstract
Androgens are critical drivers of prostate cancer. In this chapter we first discuss the canonical pathways of androgen metabolism and their alterations in prostate cancer progression, including the classical, backdoor and 5α-dione pathways, the role of pre-receptor DHT metabolism, and recent findings on oncogenic splicing of steroidogenic enzymes. Next, we discuss the activity and metabolism of non-canonical 11-oxygenated androgens that can activate wild-type AR and are less susceptible to glucuronidation and inactivation than the canonical androgens, thereby serving as an under-recognized reservoir of active ligands. We then discuss an emerging literature on the potential non-canonical role of androgen metabolizing enzymes in driving prostate cancer. We conclude by discussing the potential implications of these findings for prostate cancer progression, particularly in context of new agents such as abiraterone and enzalutamide, which target the AR-axis for prostate cancer therapy, including mechanisms of response and resistance and implications of these findings for future therapy.
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Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Elahe A Mostaghel
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. .,Department of Medicine, University of Washington, Seattle, WA, USA. .,Geriatric Research, Education and Clinical Center S-182, VA Puget Sound Health Care System, Seattle, WA, USA.
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4
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Abstract
Background Over the past two decades, parallel recognition has grown of the importance of both sex steroids and immune activity in metabolic regulation. More recently, these discrete areas have been integrated in studies examining the metabolic effects of sex steroid immunomodulation. Implicit in these studies has been a traditional, endocrine model of sex steroid delivery from the gonads to target cells, including immune cells. Thus, research to date has focused on the metabolic effects of sex steroid receptor signaling in immune cells. This endocrine model, however, overlooks the extensive capacity of immune cells to generate and metabolize sex steroids, enabling the production of sex steroids for intracrine signaling – that is, sex steroid production for signaling within the cell of origin. Intracrine function allows highly cell-autonomous regulation of sex steroid exposure, and sex steroid secretion by immune cells could confer paracrine signaling effects in neighboring cells within metabolic tissues. In this review, immune cell intracrinology will denote sex steroid production within immune cells for either intracrine or paracrine signaling. This intracrine capacity of immune cells has been well established, and prior work has supported its importance in autoimmune disorders, trauma, and cancer. The potential relevance of immune cell intracrine function to the regulation of energy balance, body weight, body composition, and insulin sensitivity has yet to be explored. Scope of review The following review will detail findings to date regarding the steroidogenic and steroid metabolizing capacity of immune cells, the regulation of immune cell intracrine function, and the biological effects of immune-derived sex steroids, including the clinical relevance of immune cell intracrinology in fields other than metabolism. These findings will serve as the basis for a proposed model of immune cell intracrinology constituting a new frontier in metabolism research. Major conclusions The development of highly sensitive mass spectrometric methods for sex steroid measurement and quantitation of metabolic flux now allows unprecedented ability to interrogate sex steroid production, metabolism and secretion by immune cells. Immune cell intracrinology could reveal key mechanisms underlying immune cell-mediated metabolic regulation. Sex steroids exert immunomodulatory effects that may influence metabolic health. Immune cells can synthesize, modify, and metabolize sex steroids. Immune cell-derived sex steroids may play intracrine, autocrine, paracrine, and possibly even endocrine roles. Immune cell steroidogenesis is a largely unexplored area of metabolism research.
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Affiliation(s)
- Katya B Rubinow
- Diabetes Institute, Department of Medicine, University of Washington, School of Medicine, 850 Republican St., Box 358055, Seattle, WA 98109, USA.
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5
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Reyes S, Varagic J, Ahmad S, VonCannon J, Kon ND, Wang H, Groban L, Cheng CP, Dell'Italia LJ, Ferrario CM. Novel Cardiac Intracrine Mechanisms Based on Ang-(1-12)/Chymase Axis Require a Revision of Therapeutic Approaches in Human Heart Disease. Curr Hypertens Rep 2017; 19:16. [PMID: 28233239 DOI: 10.1007/s11906-017-0708-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE OF THE REVIEW Drugs targeting the renin-angiotensin system (RAS), namely angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, are the most commonly prescribed drugs for patients with or at risk for cardiovascular events. However, new treatment strategies aimed at mitigating the rise of the heart failure pandemic are warranted because clinical trials show that RAS blockers have limited benefits in halting disease progression. The main goal of this review is to put forward the concept of an intracrine RAS signaling through the novel angiotensin-(1-12)/chymase axis as the main source of deleterious angiotensin II (Ang II) in cardiac maladaptive remodeling leading to heart failure (HF). RECENT FINDINGS Expanding traditional knowledge, Ang II can be produced in tissues independently from the circulatory renin-angiotensin system. In the heart, angiotensin-(1-12) [Ang-(1-12)], a recently discovered derivative of angiotensinogen, is a precursor of Ang II, and chymase rather than ACE is the main enzyme contributing to the direct production of Ang II from Ang-(1-12). The Ang-(1-12)/chymase axis is an independent intracrine pathway accounting for the trophic, contractile, and pro-arrhythmic Ang II actions in the human heart. Ang-(1-12) expression and chymase activity have been found elevated in the left atrial appendage of heart disease subjects, suggesting a pivotal role of this axis in the progression of HF. Recent meta-analysis of large clinical trials on the use of ACE inhibitors and angiotensin receptor blockers in cardiovascular disease has demonstrated an imbalance between patients that significantly benefit from these therapeutic agents and those that remain at risk for heart disease progression. Looking to find an explanation, detailed investigation on the RAS has unveiled a previously unrecognized complexity of substrates and enzymes in tissues ultimately associated with the production of Ang II that may explain the shortcomings of ACE inhibition and angiotensin receptor blockade. Discovery of the Ang-(1-12)/chymase axis in human hearts, capable of producing Ang II independently from the circulatory RAS, has led to the notion that a tissue-delimited RAS signaling in an intracrine fashion may account for the deleterious effects of Ang II in the heart, contributing to the transition from maladaptive cardiac remodeling to heart failure. Targeting intracellular RAS signaling may improve current therapies aimed at reducing the burden of heart failure.
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6
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Abstract
Heart failure and chronic renal diseases are usually progressive and only partially amenable to therapy. These disorders can be the sequelae of hypertension or worsened by hypertension. They are associated with the tissue up-regulation of multiple peptides, many of which are capable of acting within the cell interior. This article proposes that these peptides, intracrines, can form self-sustaining regulatory loops that can spread through heart or kidney, producing progressive disease. Moreover, mineralocorticoid activation seems capable of amplifying some of these peptide networks. This view suggests an expanded explanation of the pathogenesis of progressive cardiorenal disease and suggests new approaches to treatment.
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Affiliation(s)
- Richard N Re
- Ochsner Clinic Foundation, Division of Research, 1514 Jefferson Highway, New Orleans, LA 70121, USA.
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7
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Takagi M, Miki Y, Miyashita M, Hata S, Yoda T, Hirakawa H, Sagara Y, Rai Y, Ohi Y, Tamaki K, Ishida T, Suzuki T, Ouchi N, Sasano H. Intratumoral estrogen production and actions in luminal A type invasive lobular and ductal carcinomas. Breast Cancer Res Treat 2016; 156:45-55. [PMID: 26943913 DOI: 10.1007/s10549-016-3739-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/28/2016] [Indexed: 10/22/2022]
Abstract
The great majority of invasive lobular carcinoma (ILC) is estrogen-dependent luminal A type carcinoma but the details of estrogen actions and its intratumoral metabolism have not been well studied compared to invasive ductal carcinoma (IDC). We first immunolocalized estrogen-related enzymes including estrogen sulfotransferase (EST), estrogen sulfatase (STS), 17β-hydroxysteroid dehydrogenase (HSD) 1/2, and aromatase. We then evaluated the tissue concentrations of estrogens in ILC and IDC and subsequently estrogen-responsive gene profiles in these tumors in order to explore the possible differences and/or similarity of intratumoral estrogen environment of these two breast cancer subtypes. The status of STS and 17βHSD1 was significantly lower in ILCs than IDCs (p = 0.022 and p < 0.0001), but that of EST and 17βHSD2 vice versa (p < 0.0001 and p = 0.0106). In ILCs, tissue concentrations of estrone and estradiol were lower than those in IDCs (p = 0.0709 and 0.069). In addition, the great majority of estrogen response genes tended to be lower in ILCs. Among those genes above, FOXP1 was significantly higher in ILCs than in IDCs (p = 0.002). FOXP1 expression was reported to be significantly higher in relapse-free IDC patients treated with tamoxifen. Therefore, tamoxifen may be considered an option of endocrine therapy for luminal A type ILC patients. This is the first study to demonstrate the detailed and comprehensive status of intratumoral production and metabolism of estrogens and the status of estrogen response genes in luminal A-like ILC with comparison to those in luminal A-like IDCs.
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8
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Boucher E, Provost PR, Tremblay Y. C21-steroids inactivation and glucocorticoid synthesis in the developing lung. J Steroid Biochem Mol Biol 2015; 147:70-80. [PMID: 25434283 DOI: 10.1016/j.jsbmb.2014.11.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/05/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Glucocorticoids (GCs) are important regulators of lung development. The genes normally involved in GC synthesis in adrenals are co-expressed with 20α-hydroxysteroid dehydrogenase (20α-HSD) in the developing lung. In this study, C21-steroid metabolism was investigated in fetal and postnatal mouse lungs. Incubation of [(3)H]-progesterone with lung explant cultures of different perinatal developmental time points revealed two different (antenatal vs. postnatal) complex metabolization patterns. Progesterone inactivation was predominant. 20αOH-derivatives were more abundant after birth and some metabolites were 5α-reduced. Using [(3)H]-progesterone as substrate, corticosterone synthesis was only observed in a fraction of lung explants from gestation day (GD) 15.5. Neither aldosterone synthase nor P450c17 activity was observed. With epithelial-enriched primary cell cultures, deoxycorticosterone synthesis from [(3)H]-progesterone was observed. With lung explants incubated with [(3)H]-corticosterone as substrate, [(3)H]-4-pregnen-21-ol-3,11,20-trione (11-dehydrocorticosterone), the product of 11β-HSD2, accumulated in higher proportion on GD 15.5 than at later developmental time points. The temporal correlation observed between levels of progesterone inactivation by 20α-HSD (higher after birth) and the sensitivity of lung development to GCs suggests a role for 20α-HSD in the modulation of GR occupancy through the control of 21-hydroxylase substrate and product levels. In conclusion, the developing lung is characterized by effective inactivation of c21-steroids by 20α-HSD. The formation of active GCs from the "adrenal"-like pathway was observed with some lung explants and primary epithelial cell cultures. Coexistence of this GC synthesis pathway with 20α-HSD activity strongly suggests local regulation of GC action and is compatible with intracrine/paracrine actions of GC.
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Affiliation(s)
- Eric Boucher
- Reproduction, Mother and Youth Health, Centre de recherche du CHU de Québec, Québec, QC, Canada; Centre de Recherche en Biologie de la Reproduction (CRBR), Faculty of Medicine, Laval University, Québec, QC, Canada
| | - Pierre R Provost
- Reproduction, Mother and Youth Health, Centre de recherche du CHU de Québec, Québec, QC, Canada; Department of Obstetrics/Gynecology & Reproduction, Faculty of Medicine, Laval University, Québec, QC, Canada; Centre de Recherche en Biologie de la Reproduction (CRBR), Faculty of Medicine, Laval University, Québec, QC, Canada
| | - Yves Tremblay
- Reproduction, Mother and Youth Health, Centre de recherche du CHU de Québec, Québec, QC, Canada; Department of Obstetrics/Gynecology & Reproduction, Faculty of Medicine, Laval University, Québec, QC, Canada; Centre de Recherche en Biologie de la Reproduction (CRBR), Faculty of Medicine, Laval University, Québec, QC, Canada.
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9
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Shibata Y, Arai S, Honma S. Methodological approach to the intracrine study and estimation of DHEA and DHEA-S using liquid chromatography-tandem mass spectrometry (LC-MS/MS). J Steroid Biochem Mol Biol 2015; 145:193-9. [PMID: 24794825 DOI: 10.1016/j.jsbmb.2014.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/18/2014] [Accepted: 04/02/2014] [Indexed: 12/20/2022]
Abstract
A reliable and sensitive method for analyzing steroids using liquid chromatography tandem mass spectrometry (LC-MS/MS) is required for research concerning dehydroepiandrosterone (DHEA), which plays a central role in steroid hormone biosynthesis and metabolism. Furthermore, after the first proposal of the concept of intracrine DHEA, stable isotope tracer analysis, which is useful for structural recognition as well as determination of steroids, has been required to evaluate physiological action and hormone biosynthesis/metabolism in target organs. We describe sample processing and analysis methods for simultaneous quantification of multiple hormones, including DHEA, in serum, saliva and tissue using LC-MS/MS. A derivatization technique compatible with each functional group for measuring 3β-hydroxy-5-enes, such as DHEA and 5α/5β-steroids, with high sensitivity and specificity is also described. Finally, we describe a newly developed method for intracrine research using stable isotope-labeled (13)C-steroid substrates with tracer analysis of their metabolites by LC-MS/MS.This article is part of a Special Issue entitled'Essential role of DHEA'.
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Affiliation(s)
- Yasuhiro Shibata
- Department of Urology, Gunma University Graduate School of Medicine, Maebashi, Japan.
| | - Seiji Arai
- Department of Urology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Seijiro Honma
- School of Health Science, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
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10
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Adams JS, Rafison B, Witzel S, Reyes RE, Shieh A, Chun R, Zavala K, Hewison M, Liu PT. Regulation of the extrarenal CYP27B1-hydroxylase. J Steroid Biochem Mol Biol 2014; 144 Pt A:22-7. [PMID: 24388948 PMCID: PMC4077994 DOI: 10.1016/j.jsbmb.2013.12.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 12/19/2022]
Abstract
Provided here is a collective review of research on the extrarenal CYP27B1-hydroxylase that shapes our current and expanding vision of the role this enzyme plays in the intracrinology and paracrinology, as opposed to the traditional endocrinology, of vitamin D to regulate the innate and adaptive immune responses, particularly in human granuloma-forming diseases like tuberculosis. Special emphasis is placed on soluble factors (i.e., cytokines) in the local microenvironment of these human diseases that coordinate amplification and feedback inhibition of the macrophage CYP27B1-hydroxylase. Principal among these factors are Type I and Type II interferons (IFNs); the Type II IFN, IFN-γ, stimulates the production of 1,25-dihydroxyvitamin D (1,25(OH)2D) from 25-hydroxyvitamin D (25OHD) by the granuloma-forming disease-activated macrophage, while the Type I IFNs, IFN-α and IFN-β, block the hydroxylation reaction. The Type I IFN response is associated with more aggressive disease, while the Type II IFN response, the one that promotes 1,25(OH)2D production by the macrophage, is associated with more confined disease. Tilting the balance in the human immune response toward a confined disease phenotype is enabled by the presence of sufficient extracellular 25OHD to modulate IFN-γ-promoted and substrate 25OH-driven intracellular synthesis of 1,25(OH)2D. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
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Affiliation(s)
- John S Adams
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States; Department of Molecular, Cell and Developmental Biology, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States; Department of Medicine, David Geffen School of Medicine, Los Angeles, CA 90095-7322, United States.
| | - Brandon Rafison
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States.
| | - Sten Witzel
- Clinical and Translational Research Center, Center for the Health Sciences, David Geffen School of Medicine, 10833 Le Conte Avenue, BE-144, Los Angeles, CA 90095, United States.
| | - Rachel E Reyes
- Department of Medicine, David Geffen School of Medicine, Los Angeles, CA 90095-7322, United States.
| | - Albert Shieh
- Department of Medicine, David Geffen School of Medicine, Los Angeles, CA 90095-7322, United States.
| | - Rene Chun
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States.
| | - Kathryn Zavala
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States.
| | - Martin Hewison
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States; Department of Molecular, Cell and Developmental Biology, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States.
| | - Philip T Liu
- Orthopaedic Hospital Research Center and Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 615 Charles E. Young Dr. South, Ste. 410, Los Angeles, CA 90095-7358, United States; Department of Medicine, David Geffen School of Medicine, Los Angeles, CA 90095-7322, United States.
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11
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Chun RF, Peercy BE, Orwoll ES, Nielson CM, Adams JS, Hewison M. Vitamin D and DBP: the free hormone hypothesis revisited. J Steroid Biochem Mol Biol 2014; 144 Pt A:132-7. [PMID: 24095930 PMCID: PMC3976473 DOI: 10.1016/j.jsbmb.2013.09.012] [Citation(s) in RCA: 298] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/20/2013] [Accepted: 09/24/2013] [Indexed: 12/21/2022]
Abstract
The last five years have witnessed a remarkable renaissance in vitamin D research and a complete re-evaluation of its benefits to human health. Two key factors have catalyzed these changes. First, it now seems likely that localized, tissue-specific, conversion of 25-hydroxyvitamin D (25OHD) to 1,25-dihydroxyvitamin D (1,25(OH)2D) drives many of the newly recognized effects of vitamin D on human health. The second key factor concerns the ongoing discussion as to what constitutes adequate or optimal serum vitamin D (25OHD) status, with the possibility that vitamin D-deficiency is common to communities across the globe. These two concepts appear to be directly linked when low serum concentrations of 25OHD compromise intracrine generation of 1,25(OH)2D within target tissues. But, is this an over-simplification? Pro-hormone 25OHD is a lipophilic molecule that is transported in the circulation bound primarily to vitamin D binding protein (DBP). While the association between 25OHD and DBP is pivotal for renal handling of 25OHD and endocrine synthesis of 1,25(OH)2D, what is the role of DBP for extra-renal synthesis of 1,25(OH)2D? We hypothesize that binding to DBP impairs delivery of 25OHD to the vitamin D-activating enzyme 1α-hydroxylase in some target cells. Specifically, it is unbound, 'free' 25OHD that drives many of the non-classical actions of vitamin D. Levels of 'free' 25OHD are dependent on the concentration of DBP and alternative serum binding proteins such as albumin, but will also be influenced by variations in DBP binding affinity for specific vitamin D metabolites. The aim of this review will be to discuss the merits of 'free 25OHD' as an alternative marker of vitamin D status, particularly in the context of non-classical responses to vitamin D. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
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Affiliation(s)
- Rene F Chun
- Orthopaedic Hospital Research Center, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Bradford E Peercy
- Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Eric S Orwoll
- Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR 97201, USA
| | - Carrie M Nielson
- Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR 97201, USA
| | - John S Adams
- Orthopaedic Hospital Research Center, University of California Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Martin Hewison
- Orthopaedic Hospital Research Center, University of California Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA.
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12
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Re RN. A possible mechanism for the progression of chronic renal disease and congestive heart failure. ACTA ACUST UNITED AC 2015; 9:54-63. [PMID: 25539896 DOI: 10.1016/j.jash.2014.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 09/11/2014] [Accepted: 09/13/2014] [Indexed: 12/15/2022]
Abstract
Chronic neurologic diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as various forms of chronic renal disease and systolic congestive heart failure, are among the most common progressive degenerative disorders encountered in medicine. Each disease follows a nearly relentless course, albeit at varying rates, driven by progressive cell dysfunction and drop-out. The neurologic diseases are characterized by the progressive spread of disease-causing proteins (prion-like proteins) from cell to cell. Recent evidence indicates that cell autonomous renin angiotensin systems operate in heart and kidney, and it is known that functional intracrine proteins can also spread between cells. This then suggests that certain progressive degenerative cardiovascular disorders such as forms of chronic renal insufficiency and systolic congestive heart failure result from dysfunctional renin angiotensin system intracrine action spreading in kidney or myocardium.
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13
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Abstract
There is some confusion in the literature about steroidogenesis in endocrine glands and steroidogenesis in peripheral intracrine tissues. The objective of the present review is to bring some clarifications and better understanding about steroidogenesis in these two types of tissues. Concerns about substrate specificity, kinetic constants and place of enzymes in the pathway have been discussed. The role of 17α-hydroxylase/17-20 lyase (CYP17A1) in the production of dehydroepiandrosterone and back-door pathways of dihydrotestosterone biosynthesis is also analyzed. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".
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Affiliation(s)
- Van Luu-The
- Research Center in Molecular Endocrinology, Oncology and Human Genomics (CREMOGH) and Department of Molecular Medicine, Faculty of Medicine, Laval University and the CHU de Quebec Research Center, Quebec City, Canada.
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