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Vega-Vásquez T, Langgartner D, Wang JY, Reber SO, Picard M, Basualto-Alarcón C. Mitochondrial morphology in the mouse adrenal cortex: Influence of chronic psychosocial stress. Psychoneuroendocrinology 2024; 160:106683. [PMID: 38086320 PMCID: PMC10872515 DOI: 10.1016/j.psyneuen.2023.106683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 10/16/2023] [Accepted: 11/19/2023] [Indexed: 01/02/2024]
Abstract
Mitochondria within the adrenal cortex play a key role in synthesizing steroid hormones. The adrenal cortex is organized in three functionally specialized zones (glomerulosa, fasciculata, and reticularis) that produce different classes of steroid hormones in response to various stimuli, including psychosocial stress. Given that the functions and morphology of mitochondria are dynamically related and respond to stress, we applied transmission electron microscopy (TEM) to examine potential differences in mitochondrial morphology under basal and chronic psychosocial stress conditions. We used the chronic subordinate colony housing (CSC) paradigm, a murine model of chronic psychosocial stress. Our findings quantitatively define how mitochondrial morphology differs among each of the three adrenal cortex zones under basal conditions, and show that chronic psychosocial stress mainly affected mitochondria in the zona glomerulosa, shifting their morphology towards the more typical glucocorticoid-producing zona fasciculata mitochondrial phenotype. Analysis of adrenocortical lipid droplets that provide cholesterol for steroidogenesis showed that chronic psychosocial stress altered lipid droplet diameter, without affecting droplet number or inter-organellar mitochondria-lipid droplet interactions. Together, our findings support the hypothesis that each adrenal cortex layer is characterized by morphologically distinct mitochondria and that this adrenal zone-specific mitochondrial morphology is sensitive to environmental stimuli, including chronic psychosocial stressors. Further research is needed to define the role of these stress-induced changes in mitochondrial morphology, particularly in the zona glomerulosa, on stress resilience and related behaviors.
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Affiliation(s)
- Tamara Vega-Vásquez
- Laboratory of Cellular Physiology and Metabolism, Health Sciences Department, University of Aysén, Coyhaique, Chile
| | - Dominik Langgartner
- Laboratory for Molecular Psychosomatics, Department of Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, Ulm, Germany
| | - Jennifer Y Wang
- School of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Stefan O Reber
- Laboratory for Molecular Psychosomatics, Department of Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, Ulm, Germany
| | - Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, USA; Department of Neurology, H. Houston Merritt Center, Columbia University Translational Neuroscience Initiative, Columbia University Irving Medical Center, New York, USA; New York State Psychiatric Institute, New York, USA
| | - Carla Basualto-Alarcón
- Laboratory of Cellular Physiology and Metabolism, Health Sciences Department, University of Aysén, Coyhaique, Chile; Anatomy and Legal Medicine Department, Faculty of Medicine, University of Chile, Santiago, Chile.
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2
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Sacher S, Mukherjee A, Ray A. Deciphering structural aspects of reverse cholesterol transport: mapping the knowns and unknowns. Biol Rev Camb Philos Soc 2023; 98:1160-1183. [PMID: 36880422 DOI: 10.1111/brv.12948] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/03/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023]
Abstract
Atherosclerosis is a major contributor to the onset and progression of cardiovascular disease (CVD). Cholesterol-loaded foam cells play a pivotal role in forming atherosclerotic plaques. Induction of cholesterol efflux from these cells may be a promising approach in treating CVD. The reverse cholesterol transport (RCT) pathway delivers cholesteryl ester (CE) packaged in high-density lipoproteins (HDL) from non-hepatic cells to the liver, thereby minimising cholesterol load of peripheral cells. RCT takes place via a well-organised interplay amongst apolipoprotein A1 (ApoA1), lecithin cholesterol acyltransferase (LCAT), ATP binding cassette transporter A1 (ABCA1), scavenger receptor-B1 (SR-B1), and the amount of free cholesterol. Unfortunately, modulation of RCT for treating atherosclerosis has failed in clinical trials owing to our lack of understanding of the relationship between HDL function and RCT. The fate of non-hepatic CEs in HDL is dependent on their access to proteins involved in remodelling and can be regulated at the structural level. An inadequate understanding of this inhibits the design of rational strategies for therapeutic interventions. Herein we extensively review the structure-function relationships that are essential for RCT. We also focus on genetic mutations that disturb the structural stability of proteins involved in RCT, rendering them partially or completely non-functional. Further studies are necessary for understanding the structural aspects of RCT pathway completely, and this review highlights alternative theories and unanswered questions.
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Affiliation(s)
- Sukriti Sacher
- Department of Computational Biology, Indraprastha Institute of Information Technology, Okhla Phase III, New Delhi, 110019, India
| | - Abhishek Mukherjee
- Dhiti Life Sciences Pvt Ltd, B-107, Okhla Phase I, New Delhi, 110020, India
| | - Arjun Ray
- Department of Computational Biology, Indraprastha Institute of Information Technology, Okhla Phase III, New Delhi, 110019, India
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3
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Shen WJ, Cortez Y, Singh A, Chen W, Azhar S, Kraemer FB. Mice deficient in ER protein seipin have reduced adrenal cholesteryl ester lipid droplet formation and utilization. J Lipid Res 2022; 63:100309. [PMID: 36332685 PMCID: PMC9703635 DOI: 10.1016/j.jlr.2022.100309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Cholesteryl ester (CE)-rich lipid droplets (LDs) accumulate in steroidogenic tissues under physiological conditions and constitute an important source of cholesterol as the precursor for the synthesis of all steroid hormones. The mechanisms specifically involved in CE-rich LD formation have not been directly studied and are assumed by most to occur in a fashion analogous to triacylglycerol-rich LDs. Seipin is an endoplasmic reticulum protein that forms oligomeric complexes at endoplasmic reticulum-LD contact sites, and seipin deficiency results in severe alterations in LD maturation and morphology as seen in Berardinelli-Seip congenital lipodystrophy type 2. While seipin is critical for triacylglycerol-rich LD formation, no studies have directly addressed whether seipin is important for CE-rich LD biogenesis. To address this issue, mice with deficient expression of seipin specifically in adrenal, testis, and ovary, steroidogenic tissues that accumulate CE-rich LDs under normal physiological conditions, were generated. We found that the steroidogenic-specific seipin-deficient mice displayed a marked reduction in LD and CE accumulation in the adrenals, demonstrating the pivotal role of seipin in CE-rich LD accumulation/formation. Moreover, the reduction in CE-rich LDs was associated with significant defects in adrenal and gonadal steroid hormone production that could not be completely reversed by addition of exogenous lipoprotein cholesterol. We conclude that seipin has a heretofore unappreciated role in intracellular cholesterol trafficking.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Stanford, CA, USA; Geriatric Research, Education, and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
| | - Yuan Cortez
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Amar Singh
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Weiqin Chen
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Salman Azhar
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Stanford, CA, USA; Geriatric Research, Education, and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
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4
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Vishnyakova TG, Bocharov AV, Baranova IN, Kurlander R, Drake SK, Chen Z, Amar M, Sviridov D, Vaisman B, Poliakov E, Remaley AT, Eggerman TL, Patterson AP. SR-BI mediates neutral lipid sorting from LDL to lipid droplets and facilitates their formation. PLoS One 2020; 15:e0240659. [PMID: 33057430 PMCID: PMC7561250 DOI: 10.1371/journal.pone.0240659] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 09/30/2020] [Indexed: 12/30/2022] Open
Abstract
SR-BI binds various lipoproteins, including HDL, LDL as well as VLDL, and mediates selective cholesteryl ester (CE) uptake. HDL derived CE accumulates in cellular lipid droplets (LDs), which also store triacylglycerol (TAG). We hypothesized that SR-BI could significantly facilitate LD formation, in part, by directly transporting LDL derived neutral lipids (NL) such as CE and TAG into LDs without lipolysis and de novo lipid synthesis. SR-BI overexpression greatly increased LDL uptake and LD formation in stably transfected HeLa cells (SR-BI-HeLa). LDs isolated from SR-BI-HeLa contained 4- and 7-times more CE and TAG, respectively, than mock-transfected HeLa (Mock-HeLa). In contrast, LDL receptor overexpression in HeLa (LDLr-HeLa) greatly increased LDL uptake, degradation with moderate 1.5- and 2-fold increases of CE and TAG, respectively. Utilizing CE and TAG analogs, BODIPY-TAG (BP-TAG) and BODIPY-CE (BP-CE), for tracking LDL NL, we found that after initial binding of LDL to SR-BI-HeLa, apoB remained at the cell surface, while BP-CE and BP-TAG were sorted and simultaneously transported together to LDs. Both lipids demonstrated limited internalization to lysosomes or endoplasmic reticulum in SR-BI-HeLa. In LDLr-HeLa, NLs demonstrated clear lysosomal sequestration without their sorting to LDs. An inhibition of TAG and CE de novo synthesis by 90-95% only reduced TAG and CE LD content by 45-50%, and had little effect on BP-CE and BP-TAG transport to LDs in SR-BI HeLa. Furthermore, intravenous infusion of 1-2 mg of LDL increased liver LDs in normal (WT) but not in SR-BI KO mice. Mice transgenic for human SR-BI demonstrated higher liver LD accumulation than WT mice. Finally, Electro Spray Infusion Mass Spectrometry (ESI-MS) using deuterated d-CE found that LDs accumulated up to 40% of unmodified d-CE LDL. We conclude that SR-BI mediates LDL-induced LD formation in vitro and in vivo. In addition to cytosolic NL hydrolysis and de novo lipid synthesis, this process includes selective sorting and transport of LDL NL to LDs with limited lysosomal NL sequestration and the transport of LDL CE, and TAG directly to LDs independently of de novo synthesis.
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Affiliation(s)
- Tatyana G. Vishnyakova
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
| | - Alexander V. Bocharov
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
- * E-mail:
| | - Irina N. Baranova
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
| | - Roger Kurlander
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
| | - Steven K. Drake
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
| | - Zhigang Chen
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
| | - Marcelo Amar
- National Heart, Lung and Blood Institute, Bethesda, Maryland, United
States of America
| | - Denis Sviridov
- National Heart, Lung and Blood Institute, Bethesda, Maryland, United
States of America
| | - Boris Vaisman
- National Heart, Lung and Blood Institute, Bethesda, Maryland, United
States of America
| | - Eugenia Poliakov
- National Eye Institute, Bethesda, Maryland, United States of
America
| | - Alan T. Remaley
- National Heart, Lung and Blood Institute, Bethesda, Maryland, United
States of America
| | - Thomas L. Eggerman
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
- National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda,
Maryland, United States of America
| | - Amy P. Patterson
- Clinical Center, The National Institutes of Health, Bethesda, Maryland,
United States of America
- National Heart, Lung and Blood Institute, Bethesda, Maryland, United
States of America
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5
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Wang J, Jin H, Schlenke T, Yang Y, Wang F, Yao H, Fang Q, Ye G. Lipidomics reveals how the endoparasitoid wasp Pteromalus puparum manipulates host energy stores for its young. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158736. [PMID: 32438058 DOI: 10.1016/j.bbalip.2020.158736] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/29/2020] [Accepted: 05/06/2020] [Indexed: 02/02/2023]
Abstract
Endoparasitoid wasps inject venom along with their eggs to adjust the physiological and nutritional environment inside their hosts to benefit the development of their offspring. In particular, wasp venoms are known to modify host lipid metabolism, lipid storage in the fat body, and release of lipids into the hemolymph, but how venoms accomplish these functions remains unclear. Here, we use an UPLC-MS-based lipidomics approach to analyze the identities and concentrations of lipids in both fat body and hemolymph of host cabbage butterfly (Pieris rapae) infected by the pupal endoparasitoid Pteromalus puparum. During infection, host fat body levels of highly unsaturated, soluble triacylglycerides (TAGs) increased while less unsaturated, less soluble forms decreased. Furthermore, in infected host hemolymph, overall levels of TAG and phospholipids (the major component of cell membranes) increased, suggesting that fat body cells are destroyed and their contents are dispersed. Altogether, these data suggest that wasp venom induces host fat body TAGs to be transformed into lower melting point (more liquid) forms and released into the host hemolymph following infection, allowing simple absorption and nutritional acquisition by wasp larvae. Finally, cholesteryl esters (CEs, a dietary lipid derived from cholesterol) increased in host hemolymph following infection with no concomitant decrease in host cholesterol, implying that the wasp may provide this necessary food resource to its offspring via its venom. This study provides novel insight into how parasitoid infection alters lipid metabolism in insect hosts, and begins to uncover the wasp venom proteins responsible for host physiological changes and offspring development.
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Affiliation(s)
- Jiale Wang
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - Hongxia Jin
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Todd Schlenke
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - Yi Yang
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fang Wang
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hongwei Yao
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qi Fang
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Gongyin Ye
- State Key Laboratory of Rice Biology & Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
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6
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Wang W, Hao X, Han L, Yan Z, Shen WJ, Dong D, Hasbargen K, Bittner S, Cortez Y, Greenberg AS, Azhar S, Kraemer FB. Tissue-Specific Ablation of ACSL4 Results in Disturbed Steroidogenesis. Endocrinology 2019; 160:2517-2528. [PMID: 31504388 PMCID: PMC6773434 DOI: 10.1210/en.2019-00464] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/21/2019] [Indexed: 01/14/2023]
Abstract
ACSL4 is a member of the ACSL family that catalyzes the conversion of long-chain fatty acids to acyl-coenzyme As, which are essential for fatty-acid incorporation and utilization in diverse metabolic pathways, including cholesteryl ester synthesis. Steroidogenic tissues such as the adrenal gland are particularly enriched in cholesteryl esters of long-chain polyunsaturated fatty acids, which constitute an important pool supplying cholesterol for steroid synthesis. The current studies addressed whether ACSL4 is required for normal steroidogenesis. CYP11A1 promoter‒mediated Cre was used to generate steroid tissue‒specific ACSL4 knockout (KO) mice. Results demonstrated that ACSL4 plays an important role in adrenal cholesteryl ester formation, as well as in determining the fatty acyl composition of adrenal cholesteryl esters, with ACSL4 deficiency leading to reductions in cholesteryl ester storage and alterations in cholesteryl ester composition. Statistically significant reductions in corticosterone and testosterone production, but not progesterone production, were observed in vivo, and these deficits were accentuated in ex vivo and in vitro studies of isolated steroid tissues and cells from ACSL4-deficient mice. However, these effects on steroid production appear to be due to reductions in cholesteryl ester stores rather than disturbances in signaling pathways. We conclude that ACSL4 is dispensable for normal steroidogenesis.
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Affiliation(s)
- Wei Wang
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Xiao Hao
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Lina Han
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Zhe Yan
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
- Correspondence: Fredric B. Kraemer, MD, or Wen-Jun Shen, PhD, Division of Endocrinology, S025, Stanford University School of Medicine, Stanford, California 94305-5103. E-mail: or
| | - Dachuan Dong
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Kathrin Hasbargen
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Stefanie Bittner
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Yuan Cortez
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Andrew S Greenberg
- Obesity and Metabolism Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Salman Azhar
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Palo Alto, California
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
- Correspondence: Fredric B. Kraemer, MD, or Wen-Jun Shen, PhD, Division of Endocrinology, S025, Stanford University School of Medicine, Stanford, California 94305-5103. E-mail: or
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7
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Wang W, Yan Z, Hu J, Shen WJ, Azhar S, Kraemer FB. Scavenger receptor class B, type 1 facilitates cellular fatty acid uptake. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158554. [PMID: 31678516 DOI: 10.1016/j.bbalip.2019.158554] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023]
Abstract
SR-B1 belongs to the class B scavenger receptor, or CD36 super family. SR-B1 and CD36 share an affinity for a wide array of ligands. Although they exhibit similar ligand binding specificity, SR-B1 and CD36 have some very specific lipid transport functions. Whereas SR-B1 primarily facilitates the selective delivery of cholesteryl esters (CEs) and cholesterol from HDL particles to the liver and non-placental steroidogenic tissues, as well as participating in cholesterol efflux from cells, CD36 primarily mediates the uptake of long-chain fatty acids in high fatty acid-requiring organs such as the heart, skeletal muscle and adipose tissue. However, CD36 also mediates cholesterol efflux and facilitates selective lipoprotein-CE delivery, although less efficiently than SR-B1. Interestingly, the ability or efficiency of SR-B1 to mediate fatty acid uptake has not been reported. In this paper, using overexpression and siRNA-mediated knockdown of SR-B1, we show that SR-B1 possesses the ability to facilitate fatty acid uptake. Moreover, this function is not blocked by BLT-1, a specific chemical inhibitor of HDL-CE uptake activity of SR-B1, nor by sulfo-N-succinimidyl oleate, which inhibits fatty acid uptake by CD36. Attenuated fatty acid uptake was also observed in primary adipocytes isolated from SR-B1 knockout mice. In conclusion, facilitation of fatty acid uptake is an additional function that is mediated by SR-B1.
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Affiliation(s)
- Wei Wang
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America; Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Zhe Yan
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America; Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu, China
| | - Jie Hu
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America.
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America.
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8
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Samadi S, Ghayour-Mobarhan M, Mohammadpour A, Farjami Z, Tabadkani M, Hosseinnia M, Miri M, Heydari-Majd M, Mehramiz M, Rezayi M, Ferns GA, Avan A. High-density lipoprotein functionality and breast cancer: A potential therapeutic target. J Cell Biochem 2018; 120:5756-5765. [PMID: 30362608 DOI: 10.1002/jcb.27862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/19/2018] [Indexed: 12/16/2022]
Abstract
Breast cancer is a major cause of death globally, and particularly in developed countries. Breast cancer is influenced by cholesterol membrane content, by affecting the signaling pathways modulating cell growth, adherence, and migration. Furthermore, steroid hormones are derived from cholesterol and these play a key role in the pathogenesis of breast cancer. Although most findings have reported an inverse association between serum high-density lipoprotein (HDL)-cholesterol level and the risk of breast cancer, there have been some reports of the opposite, and the association therefore remains unclear. HDL is principally known for participating in reverse cholesterol transport and has an inverse relationship with the cardiovascular risk. HDL is heterogeneous, with particles varying in composition, size, and structure, which can be altered under different circumstances, such as inflammation, aging, and certain diseases. It has also been proposed that HDL functionality might have a bearing on the breast cancer. Owing to the potential role of cholesterol in cancer, its reduction using statins, and particularly as an adjuvant during chemotherapy may be useful in the anticancer treatment, and may also be related to the decline in cancer mortality. Reconstituted HDLs have the ability to release chemotherapeutic drugs inside the cell. As a consequence, this may be a novel way to improve therapeutic targeting for the breast cancer on the basis of detrimental impacts of oxidized HDL on cancer development.
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Affiliation(s)
- Sara Samadi
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Majid Ghayour-Mobarhan
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhooshang Mohammadpour
- Department of Clinical Pharmacy, Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra Farjami
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahla Tabadkani
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Hosseinnia
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehri Miri
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Motahareh Heydari-Majd
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehrane Mehramiz
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Majid Rezayi
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Gordon A Ferns
- Division of Medical Education, Brighton & Sussex Medical School, Brighton, UK
| | - Amir Avan
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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9
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Shen WJ, Asthana S, Kraemer FB, Azhar S. Scavenger receptor B type 1: expression, molecular regulation, and cholesterol transport function. J Lipid Res 2018; 59:1114-1131. [PMID: 29720388 DOI: 10.1194/jlr.r083121] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/26/2018] [Indexed: 12/16/2022] Open
Abstract
Cholesterol is required for maintenance of plasma membrane fluidity and integrity and for many cellular functions. Cellular cholesterol can be obtained from lipoproteins in a selective pathway of HDL-cholesteryl ester (CE) uptake without parallel apolipoprotein uptake. Scavenger receptor B type 1 (SR-B1) is a cell surface HDL receptor that mediates HDL-CE uptake. It is most abundantly expressed in liver, where it provides cholesterol for bile acid synthesis, and in steroidogenic tissues, where it delivers cholesterol needed for storage or steroidogenesis in rodents. SR-B1 transcription is regulated by trophic hormones in the adrenal gland, ovary, and testis; in the liver and elsewhere, SR-B1 is subject to posttranscriptional and posttranslational regulation. SR-B1 operates in several metabolic processes and contributes to pathogenesis of atherosclerosis, inflammation, hepatitis C virus infection, and other conditions. Here, we summarize characteristics of the selective uptake pathway and involvement of microvillar channels as facilitators of selective HDL-CE uptake. We also present the potential mechanisms of SR-B1-mediated selective cholesterol transport; the transcriptional, posttranscriptional, and posttranslational regulation of SR-B1; and the impact of gene variants on expression and function of human SR-B1. A better understanding of this unique pathway and SR-B1's role may yield improved therapies for a wide variety of conditions.
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Affiliation(s)
- Wen-Jun Shen
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Shailendra Asthana
- Drug Discovery Research Center (DDRC), Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, Faridabad 121001, Haryana, India
| | - Fredric B Kraemer
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Salman Azhar
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
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10
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Shen WJ, Azhar S, Kraemer FB. SR-B1: A Unique Multifunctional Receptor for Cholesterol Influx and Efflux. Annu Rev Physiol 2017; 80:95-116. [PMID: 29125794 DOI: 10.1146/annurev-physiol-021317-121550] [Citation(s) in RCA: 219] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The scavenger receptor, class B type 1 (SR-B1), is a multiligand membrane receptor protein that functions as a physiologically relevant high-density lipoprotein (HDL) receptor whose primary role is to mediate selective uptake or influx of HDL-derived cholesteryl esters into cells and tissues. SR-B1 also facilitates the efflux of cholesterol from peripheral tissues, including macrophages, back to liver. As a regulator of plasma membrane cholesterol content, SR-B1 promotes the uptake of lipid soluble vitamins as well as viral entry into host cells. These collective functions of SR-B1 ultimately affect programmed cell death, female fertility, platelet function, vasculature inflammation, and diet-induced atherosclerosis and myocardial infarction. SR-B1 has also been identified as a potential marker for cancer diagnosis and prognosis. Finally, the SR-B1-linked selective HDL-cholesteryl ester uptake pathway is now being evaluated as a gateway for the delivery of therapeutic and diagnostic agents. In this review, we focus on the regulation and functional significance of SR-B1 in mediating cholesterol movement into and out of cells.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
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11
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Liu HW, Law WHT, Lee LCC, Lau JCW, Lo KKW. Cyclometalated Iridium(III) Bipyridine-Phenylboronic Acid Complexes as Bioimaging Reagents and Luminescent Probes for Sialic Acids. Chem Asian J 2017; 12:1545-1556. [DOI: 10.1002/asia.201700359] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/13/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Hua-Wei Liu
- Department of Biology and Chemistry; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
| | - Wendell Ho-Tin Law
- Department of Biology and Chemistry; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
| | - Lawrence Cho-Cheung Lee
- Department of Biology and Chemistry; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
| | - Jonathan Chun-Wai Lau
- Department of Biology and Chemistry; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P.R. China
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12
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Li J, Zhou Q, Ma Z, Wang M, Shen WJ, Azhar S, Guo Z, Hu Z. Feedback inhibition of CREB signaling by p38 MAPK contributes to the negative regulation of steroidogenesis. Reprod Biol Endocrinol 2017; 15:19. [PMID: 28302174 PMCID: PMC5356319 DOI: 10.1186/s12958-017-0239-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/06/2017] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Steroidogenesis is a complex, multi-steps biological process in which, cholesterol precursor is converted to steroids in a tissue specific and tropic hormone dependent manner. Given that steroidogenesis is achieved by coordinated functioning of multiple tissue specific enzymes, many steroids intermediates/metabolites are generated during this process. Both the steroid products as well as major lipoprotein cholesterol donor, high-density lipoprotein 3 (hHDL3) have the potential to negatively regulate steroidogenesis via increased oxidative stress/reactive oxygen species (ROS) generation. METHODS In the current study, we examined the effects of treatment of a mouse model of steroidogenesis, Y1-BS1 adrenocortical tumor cells with pregnenolone, 22(R)-Hydroxycholesterol [22(R)-diol] or hHDL3 on ROS production, phosphorylation status of p38 MAPK and cAMP response element-binding protein (CREB), CREB transcriptional activity and mRNA expression of StAR, CPY11A1/P450scc and antioxidant enzymes, superoxide dismutases [Cu,ZnSOD (SOD1), MnSOD (SOD2)], catalase (CAT) and glutathione peroxidase 1 (GPX1). We also detected the steroid product in p38 MAPK inhibitor treated Y1 cells by HPLC-MS / MS. RESULTS Treatment of Y1 cells with H2O2 greatly enhanced the phosphorylation of both p38 MAPK and CREB protein. Likewise, treatment of cells with pregnenolone, 22(R) diol or hHDL3 increased ROS production measured with the oxidation-sensitive fluorescent probe 2',7'-Dichlorofluorescin diacetate (DCFH-DA). Under identical experimental conditions, treatment of cells with these agents also increased the phosphorylation of p38 MAPK and CREB. This increased CREB phosphorylation however, was associated with its decreased transcriptional activity. The stimulatory effects of pregnenolone, 22(R)-diol and hHDL3 on CREB phosphorylation was abolished by a specific p38 MAPK inhibitor, SB203580. Pregnenolone, and 22(R) diol but not hHDL3 upregulated the mRNA expression of SOD1, SOD2 and GPX1, while down-regulated the mRNA levels of StAR and CYP11A1. The p38 inhibitor SB203580 could increase the steroid production in HDL3, 22(R)-diol or pregnenolone treated cells. CONCLUSION Our data demonstrate induction of a ROS/p38 MAPK -mediated feedback inhibitory pathway by oxy-cholesterol and steroid intermediates and products attenuates steroidogenesis via inhibition of CREB transcriptional activity.
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Affiliation(s)
- Jiaxin Li
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
| | - Qian Zhou
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
| | - Zhuang Ma
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
| | - Meina Wang
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
| | - Wen-Jun Shen
- 0000 0004 0419 2556grid.280747.eGeriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA 94304 USA
- 0000000419368956grid.168010.eStanford University School of Medicine, Palo Alto, CA 94304 USA
| | - Salman Azhar
- 0000 0004 0419 2556grid.280747.eGeriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA 94304 USA
- 0000000419368956grid.168010.eStanford University School of Medicine, Palo Alto, CA 94304 USA
| | - Zhigang Guo
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
| | - Zhigang Hu
- 0000 0001 0089 5711grid.260474.3Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023 China
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13
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Yamaguchi S, Ura M, Izuta S, Okamoto A. Chemically Activatable Alkyne Tag for Low pH-Enhanced Molecular Labeling on Living Cells. Bioconjug Chem 2016; 27:1976-80. [DOI: 10.1021/acs.bioconjchem.6b00399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Satoshi Yamaguchi
- Research
Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Manami Ura
- Department
of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Shin Izuta
- Department
of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akimitsu Okamoto
- Research
Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
- Department
of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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14
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Hu Z, Li J, Kuang Z, Wang M, Azhar S, Guo Z. Cell-Specific Polymorphism and Hormonal Regulation of DNA Methylation in Scavenger Receptor Class B, Type I. DNA Cell Biol 2016; 35:280-9. [PMID: 26981684 DOI: 10.1089/dna.2015.3185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The scavenger receptor class B, type I (SR-BI), is a cell-surface glycoprotein that mediates selective uptake of high density lipoprotein (HDL)-derived cholesteryl ester. SR-BI plays an important role in cellular delivery of cholesterol. Both human and rodent SR-BI are expressed most abundantly in the liver parenchymal cells and steroidogenic cells of the adrenal gland and gonads, where the selective pathway exhibits its highest activity. In steroidogenic cells, the expression of SR-BI is regulated by trophic hormones (adrenocorticotropic hormone or gonadotropins luteinizing hormone or follicle-stimulating hormone) in concert with the regulation of steroid hormone production. DNA methylation has been implicated in a large number of biological processes mainly by regulating gene expression. The SR-BI promoter contains one CpG island (CGI) in its promoter and seven CGIs in its intronic regions. Here, we studied the DNA methylation status of SR-BI gene and provide evidence that the DNA methylation is cell specific in this gene promoter as well as in intronic regions. The DNA methylation in the SR-BI promoter is subject to N(6), 2'-O-dibutyryladenosine3':5'-cyclic monophosphate regulation in mouse adrenal Y1 cells and mouse Leydig tumor cells (MLTCs). The seven intron CGIs are methylated differentially in Y1 cells, MLTCs, ovarian granulosa cells, and mouse liver hepa 1-6 cells. Our experiments raised the possibility that DNA methylation participates in hormonal regulation of SR-BI expression in a tissue-specific manner. We further suggest that the cell-specific DNA methylation in SR-BI intronic regions may be associated with specific biological function(s) of these regions, including regulation of gene expression.
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Affiliation(s)
- Zhigang Hu
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Jiaxin Li
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Zhihui Kuang
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Meina Wang
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Salman Azhar
- 2 Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, and Stanford University School of Medicine , Palo Alto, California
| | - Zhigang Guo
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
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15
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Ogawa Y, Tanaka M. A fluorescent cholesterol analogue for observation of free cholesterol in the plasma membrane of live cells. Anal Biochem 2016; 492:49-55. [DOI: 10.1016/j.ab.2015.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/14/2015] [Accepted: 09/03/2015] [Indexed: 01/16/2023]
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16
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Mazuryk O, Suzenet F, Kieda C, Brindell M. The biological effect of the nitroimidazole derivative of a polypyridyl ruthenium complex on cancer and endothelial cells. Metallomics 2015; 7:553-66. [PMID: 25711770 DOI: 10.1039/c5mt00037h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ruthenium polypyridyl complexes [Ru(dip)2(bpy/bpy-2-nitroIm)](2+) (dip = 4,7-diphenyl-1,10-phenanthroline, bpy = 2,2'-bipyridine, bpy-2-nitroIm = 4-[3-(2-nitro-1H-imidazol-1-yl)propyl]) were found to be ca. ten times more cytotoxic against breast cancer (4T1) and human lung adenocarcinoma epithelial cells (A549) than a well-known anticancer drug, cisplatin. Even though the Ru complexes were quite cytotoxic towards FVB mouse lung microvascular endothelial cells (MLuMEC FVB) their efflux from these non transformed cells was much more efficient than from cancer ones. Both Ru complexes accumulated in cells. The cellular uptake of both Ru complexes occurs through passive diffusion while the nitroimidazole derivative is also endocytosed. They arrest cell growth in the S-phase and induce apoptosis. Such cell response can result from activation of oxidative stress by Ru complexes. The modulation of the mRNA expression profile for genes which might be involved in metastasis and angiogenesis processes by Ru complexes was analyzed for both cancer (4T1) and endothelial (MLuMEC FVB) cells. Ru complexes appeared to have a distinct impact on cell adhesion and migration as well as they affect endothelial cell vasculature. They are not only cytotoxic but are also potentially invasive and anti-metastatic agents. This work illustrates the putative future development of polypyridyl ruthenium.
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Affiliation(s)
- Olga Mazuryk
- Department of Inorganic Chemistry, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland.
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17
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Rhenium(I) polypyridine dibenzocyclooctyne complexes as phosphorescent bioorthogonal probes: Synthesis, characterization, emissive behavior, and biolabeling properties. J Inorg Biochem 2015; 148:2-10. [DOI: 10.1016/j.jinorgbio.2015.02.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/24/2015] [Accepted: 02/24/2015] [Indexed: 01/20/2023]
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18
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Langgartner D, Füchsl AM, Uschold-Schmidt N, Slattery DA, Reber SO. Chronic subordinate colony housing paradigm: a mouse model to characterize the consequences of insufficient glucocorticoid signaling. Front Psychiatry 2015; 6:18. [PMID: 25755645 PMCID: PMC4337237 DOI: 10.3389/fpsyt.2015.00018] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 01/29/2015] [Indexed: 12/30/2022] Open
Abstract
Chronic, in particular chronic psychosocial, stress is a burden of modern societies and known to be a risk factor for numerous somatic and affective disorders (in detail referenced below). However, based on the limited existence of appropriate, and clinically relevant, animal models for studying the effects of chronic stress, the detailed behavioral, physiological, neuronal, and immunological mechanisms linking stress and such disorders are insufficiently understood. To date, most chronic stress studies in animals employ intermittent exposure to the same (homotypic) or to different (heterotypic) stressors of varying duration and intensity. Such models are only of limited value, since they do not adequately reflect the chronic and continuous situation that humans typically experience. Furthermore, application of different physical or psychological stimuli renders comparisons to the mainly psychosocial stressors faced by humans, as well as between the different stress studies almost impossible. In contrast, rodent models of chronic psychosocial stress represent situations more akin to those faced by humans and consequently seem to hold more clinical relevance. Our laboratory has developed a model in which mice are exposed to social stress for 19 continuous days, namely the chronic subordinate colony housing (CSC) paradigm, to help bridge this gap. The main aim of the current review article is to provide a detailed summary of the behavioral, physiological, neuronal, and immunological consequences of the CSC paradigm, and wherever possible relate the findings to other stress models and to the human situation.
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Affiliation(s)
- Dominik Langgartner
- Laboratory for Molecular Psychosomatics, Clinic for Psychosomatic Medicine and Psychotherapy, University of Ulm, Ulm, Germany
| | - Andrea M. Füchsl
- Laboratory for Molecular Psychosomatics, Clinic for Psychosomatic Medicine and Psychotherapy, University of Ulm, Ulm, Germany
| | - Nicole Uschold-Schmidt
- Laboratory of Molecular and Cellular Neurobiology, Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - David A. Slattery
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Stefan O. Reber
- Laboratory for Molecular Psychosomatics, Clinic for Psychosomatic Medicine and Psychotherapy, University of Ulm, Ulm, Germany
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Abstract
The purpose of this article is to review fundamentals in adrenal gland histophysiology. Key findings regarding the important signaling pathways involved in the regulation of steroidogenesis and adrenal growth are summarized. We illustrate how adrenal gland morphology and function are deeply interconnected in which novel signaling pathways (Wnt, Sonic hedgehog, Notch, β-catenin) or ionic channels are required for their integrity. Emphasis is given to exploring the mechanisms and challenges underlying the regulation of proliferation, growth, and functionality. Also addressed is the fact that while it is now well-accepted that steroidogenesis results from an enzymatic shuttle between mitochondria and endoplasmic reticulum, key questions still remain on the various aspects related to cellular uptake and delivery of free cholesterol. The significant progress achieved over the past decade regarding the precise molecular mechanisms by which the two main regulators of adrenal cortex, adrenocorticotropin hormone (ACTH) and angiotensin II act on their receptors is reviewed, including structure-activity relationships and their potential applications. Particular attention has been given to crucial second messengers and how various kinases, phosphatases, and cytoskeleton-associated proteins interact to ensure homeostasis and/or meet physiological demands. References to animal studies are also made in an attempt to unravel associated clinical conditions. Many of the aspects addressed in this article still represent a challenge for future studies, their outcome aimed at providing evidence that the adrenal gland, through its steroid hormones, occupies a central position in many situations where homeostasis is disrupted, thus highlighting the relevance of exploring and understanding how this key organ is regulated. © 2014 American Physiological Society. Compr Physiol 4:889-964, 2014.
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Affiliation(s)
- Nicole Gallo-Payet
- Division of Endocrinology, Department of Medicine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, and Centre de Recherche Clinique Étienne-Le Bel of the Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Quebec, Canada
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20
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DeAngelis AM, Roy-O'Reilly M, Rodriguez A. Genetic alterations affecting cholesterol metabolism and human fertility. Biol Reprod 2014; 91:117. [PMID: 25122065 DOI: 10.1095/biolreprod.114.119883] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Single nucleotide polymorphisms (SNPs) represent genetic variations among individuals in a population. In medicine, these small variations in the DNA sequence may significantly impact an individual's response to certain drugs or influence the risk of developing certain diseases. In the field of reproductive medicine, a significant amount of research has been devoted to identifying polymorphisms which may impact steroidogenesis and fertility. This review discusses current understanding of the effects of genetic variations in cholesterol metabolic pathways on human fertility that bridge novel linkages between cholesterol metabolism and reproductive health. For example, the role of the low-density lipoprotein receptor (LDLR) in cellular metabolism and human reproduction has been well studied, whereas there is now an emerging body of research on the role of the high-density lipoprotein (HDL) receptor scavenger receptor class B type I (SR-BI) in human lipid metabolism and female reproduction. Identifying and understanding how polymorphisms in the SCARB1 gene or other genes related to lipid metabolism impact human physiology is essential and will play a major role in the development of personalized medicine for improved diagnosis and treatment of infertility.
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Affiliation(s)
| | | | - Annabelle Rodriguez
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, Connecticut
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21
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Khor VK, Ahrends R, Lin Y, Shen WJ, Adams CM, Roseman AN, Cortez Y, Teruel MN, Azhar S, Kraemer FB. The proteome of cholesteryl-ester-enriched versus triacylglycerol-enriched lipid droplets. PLoS One 2014; 9:e105047. [PMID: 25111084 PMCID: PMC4128735 DOI: 10.1371/journal.pone.0105047] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 07/19/2014] [Indexed: 12/20/2022] Open
Abstract
Within cells, lipids are stored in the form of lipid droplets (LDs), consisting of a neutral lipid core, surrounded by a phospholipid monolayer and an outer layer of protein. LDs typically accumulate either triacylglycerol (TAG) and diacylglycerol or cholesteryl ester (CE), depending on the type of tissue. Recently, there has been an increased interest in the proteins that surround LDs. LD proteins have been found to be quite diverse, from structural proteins to metabolic enzymes, proteins involved in vesicular transport, and proteins that may play a role in LD formation. Previous proteomics analyses have focused on TAG-enriched LDs, whereas CE-enriched LDs have been largely ignored. Our study has compared the LD proteins from CE-enriched LDs to TAG-enriched LDs in steroidogenic cells. In primary rat granulosa cells loaded with either HDL to produce CE-enriched LDs or fatty acids to produce TAG-enriched LDs, 61 proteins were found to be elevated in CE-enriched LDs and 40 proteins elevated in TAG-enriched LDs with 278 proteins in similar amounts. Protein expression was further validated by selected reaction monitoring (SRM) mass spectrometry (MS). SRM verified expression of 25 of 27 peptides that were previously detected by tandem mass tagging MS. Several proteins were confirmed to be elevated in CE-enriched LDs by SRM including the intermediate filament vimentin. This study is the first to compare the proteins found on CE-enriched LDs with TAG-enriched LDs and constitutes the first step in creating a better understanding of the proteins found on CE-enriched LDs in steroidogenic cells.
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Affiliation(s)
- Victor K. Khor
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, California, United States of America
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Robert Ahrends
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, United States of America
| | - Ye Lin
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, California, United States of America
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, California, United States of America
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Christopher M. Adams
- Mass Spectrometry Center, Stanford University, Stanford, California, United States of America
| | - Ann Nomoto Roseman
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Yuan Cortez
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Mary N. Teruel
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, United States of America
| | - Salman Azhar
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University, Stanford, California, United States of America
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Fredric B. Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, California, United States of America
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
- * E-mail:
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Shen WJ, Hu J, Hu Z, Kraemer FB, Azhar S. Scavenger receptor class B type I (SR-BI): a versatile receptor with multiple functions and actions. Metabolism 2014; 63:875-86. [PMID: 24854385 PMCID: PMC8078058 DOI: 10.1016/j.metabol.2014.03.011] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 03/12/2014] [Accepted: 03/18/2014] [Indexed: 11/16/2022]
Abstract
Scavenger receptor class B type I (SR-BI), is a physiologically relevant HDL receptor that mediates selective uptake of lipoprotein (HDL)-derived cholesteryl ester (CE) in vitro and in vivo. Mammalian SR-BI is a 509-amino acid, ~82 kDa glycoprotein that contains N- and C-terminal cytoplasmic domains, two-transmembrane domains, as well as a large extracellular domain containing 5-6 cysteine residues and multiple sites for N-linked glycosylation. The size and structural characteristics of SR-BI, however, vary considerably among lower vertebrates and insects. Recently, significant progress has been made in understanding the molecular mechanisms involved in the posttranscriptional/posttranslational regulation of SR-BI in a tissue specific manner. The purpose of this review is to summarize the current body of knowledge about the events and molecules connected with the posttranscriptional/posttranslational regulation of SR-BI and to update the molecular and functional characteristics of the insect SR-BI orthologs.
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MESH Headings
- Animals
- Biological Transport
- Gene Expression Regulation
- Glycosylation
- Humans
- Insect Proteins/chemistry
- Insect Proteins/genetics
- Insect Proteins/metabolism
- Lipoproteins, HDL/chemistry
- Lipoproteins, HDL/genetics
- Lipoproteins, HDL/metabolism
- Liver/metabolism
- Organ Specificity
- Protein Conformation
- Protein Processing, Post-Translational
- Receptors, Lipoprotein/chemistry
- Receptors, Lipoprotein/genetics
- Receptors, Lipoprotein/metabolism
- Scavenger Receptors, Class B/chemistry
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
- Species Specificity
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Affiliation(s)
- Wen-Jun Shen
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Jie Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Zhigang Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Fredric B Kraemer
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Salman Azhar
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Gastroenterology and Hepatology, Stanford University, Stanford, California 94305.
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Srisen K, Röhrl C, Meisslitzer-Ruppitsch C, Ranftler C, Ellinger A, Pavelka M, Neumüller J. Human endothelial progenitor cells internalize high-density lipoprotein. PLoS One 2013; 8:e83189. [PMID: 24386159 PMCID: PMC3875452 DOI: 10.1371/journal.pone.0083189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/10/2013] [Indexed: 12/15/2022] Open
Abstract
Endothelial progenitor cells (EPCs) originate either directly from hematopoietic stem cells or from a subpopulation of monocytes. Controversial views about intracellular lipid traffic prompted us to analyze the uptake of human high density lipoprotein (HDL), and HDL-cholesterol in human monocytic EPCs. Fluorescence and electron microscopy were used to investigate distribution and intracellular trafficking of HDL and its associated cholesterol using fluorescent surrogates (bodipy-cholesterol and bodipy-cholesteryl oleate), cytochemical labels and fluorochromes including horseradish peroxidase and Alexa Fluor® 568. Uptake and intracellular transport of HDL were demonstrated after internalization periods from 0.5 to 4 hours. In case of HDL-Alexa Fluor® 568, bodipy-cholesterol and bodipy-cholesteryl oleate, a photooxidation method was carried out. HDL-specific reaction products were present in invaginations of the plasma membrane at each time of treatment within endocytic vesicles, in multivesicular bodies and at longer periods of uptake, also in lysosomes. Some HDL-positive endosomes were arranged in form of "strings of pearl"- like structures. HDL-positive multivesicular bodies exhibited intensive staining of limiting and vesicular membranes. Multivesicular bodies of HDL-Alexa Fluor® 568-treated EPCs showed multilamellar intra-vacuolar membranes. At all periods of treatment, labeled endocytic vesicles and organelles were apparent close to the cell surface and in perinuclear areas around the Golgi apparatus. No HDL-related particles could be demonstrated close to its cisterns. Electron tomographic reconstructions showed an accumulation of HDL-containing endosomes close to the trans-Golgi-network. HDL-derived bodipy-cholesterol was localized in endosomal vesicles, multivesicular bodies, lysosomes and in many of the stacked Golgi cisternae and the trans-Golgi-network Internalized HDL-derived bodipy-cholesteryl oleate was channeled into the lysosomal intraellular pathway and accumulated prominently in all parts of the Golgi apparatus and in lipid droplets. Subsequently, also the RER and mitochondria were involved. These studies demonstrated the different intracellular pathway of HDL-derived bodipy-cholesterol and HDL-derived bodipy-cholesteryl oleate by EPCs, with concomitant.
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Affiliation(s)
- Kaemisa Srisen
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Clemens Röhrl
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Claudia Meisslitzer-Ruppitsch
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Carmen Ranftler
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Adolf Ellinger
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Margit Pavelka
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Josef Neumüller
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
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Law WHT, Lee LCC, Louie MW, Liu HW, Ang TWH, Lo KKW. Phosphorescent Cellular Probes and Uptake Indicators Derived from Cyclometalated Iridium(III) Bipyridine Complexes Appended with a Glucose or Galactose Entity. Inorg Chem 2013; 52:13029-41. [DOI: 10.1021/ic401714p] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Wendell Ho-Tin Law
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Lawrence Cho-Cheung Lee
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Man-Wai Louie
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Hua-Wei Liu
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Tim Wai-Hung Ang
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Kenneth Kam-Wing Lo
- Institute of Molecular Functional
Materials [Areas of Excellence Scheme, University Grants Committee
(Hong Kong)] and Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
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25
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Hu Z, Shen WJ, Cortez Y, Tang X, Liu LF, Kraemer FB, Azhar S. Hormonal regulation of microRNA expression in steroid producing cells of the ovary, testis and adrenal gland. PLoS One 2013; 8:e78040. [PMID: 24205079 PMCID: PMC3810252 DOI: 10.1371/journal.pone.0078040] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/06/2013] [Indexed: 12/21/2022] Open
Abstract
Background Given the emerging roles of miRNAs as potential posttranscriptional/posttranslational regulators of the steroidogenic process in adrenocortical and gonadal cells, we sought to determine miRNA profiles in rat adrenals from animals treated with vehicle, ACTH, 17α-E2 or dexamethasone. Key observations were also confirmed using hormone (Bt2cAMP)-treated mouse Leydig tumor cells, MLTC-1, and primary rat ovarian granulosa cells. Methodology RNA was extracted from rat adrenal glands and miRNA profiles were established using microarray and confirmed with qRT-PCR. The expression of some of the hormone-sensitive miRNAs was quantified in MLTC-1 and granulosa cells after stimulation with Bt2cAMP. Targets of hormonally altered miRNAs were explored by qRT-PCR and Western blotting in adrenals and granulosa cells. Results Adrenals from ACTH, 17α-E2 and dexamethasone treated rats exhibited miRNA profiles distinct from control animals. ACTH up-regulated the expression of miRNA-212, miRNA-182, miRNA-183, miRNA-132, and miRNA-96 and down-regulated the levels of miRNA-466b, miRNA-214, miRNA-503, and miRNA-27a. The levels of miR-212, miRNA-183, miRNA-182, miRNA-132, miRNA-370, miRNA-377, and miRNA-96 were up-regulated, whereas miR-125b, miRNA-200b, miR-122, miRNA-466b, miR-138, miRNA-214, miRNA-503 and miRNA27a were down-regulated in response to 17α-E2 treatment. Dexamethasone treatment decreased miRNA-200b, miR-122, miR-19a, miRNA-466b and miRNA27a levels, but increased miRNA-183 levels. Several adrenal miRNAs are subject to regulation by more than one hormone. Significant cAMP-induced changes in certain miRNAs were also noted in MLTC-1 and granulosa cells. Some of the hormone-induced miRNAs in steroidogenic cells were predicted to target proteins involved in lipid metabolism/steroidogenesis. We also obtained evidence that miR-132 and miRNA-214 inhibit the expression of SREBP-1c and LDLR, respectively. Conclusion Our results demonstrate that expression of a number of miRNAs in steroidogenic cells of the testis, ovary and adrenal glands is subject to hormonal regulation and that miRNAs and their regulation by specific hormones are likely to play a key role in posttranscriptional/posttranslational regulation of steroidogenesis.
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Affiliation(s)
- Zhigang Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Endocrinology, Stanford University, Stanford, California, United States of America
| | - Wen-Jun Shen
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Endocrinology, Stanford University, Stanford, California, United States of America
| | - Yuan Cortez
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Xudong Tang
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Endocrinology, Stanford University, Stanford, California, United States of America
| | - Li-Fen Liu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Endocrinology, Stanford University, Stanford, California, United States of America
| | - Fredric B. Kraemer
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Endocrinology, Stanford University, Stanford, California, United States of America
| | - Salman Azhar
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, United States of America
- Division of Gastroenterology and Hepatology, Stanford University, Stanford, California, United States of America
- * E-mail:
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26
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Füchsl AM, Uschold-Schmidt N, Reber SO. Chronic psychosocial stress in male mice causes an up-regulation of scavenger receptor class B type 1 protein in the adrenal glands. Stress 2013; 16:461-8. [PMID: 23566157 DOI: 10.3109/10253890.2013.793303] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mice exposed to chronic subordinate colony housing (CSC, 19 days) show an exaggerated adrenal corticosterone response to an acute heterotypic stressor (elevated platform (EPF), 5 min) despite no difference from EPF-exposed single-housed control (SHC) mice in corticotropin (ACTH) secretion. In the present study, we asked the question whether this CSC-induced increase in adrenal capability to produce and secrete corticosterone is paralleled by an enhanced adrenal availability and/or mobilization capacity of the corticosterone precursor molecule cholesterol. Employing oil-red staining and western blot analysis we revealed comparable relative density of cortical lipid droplets and relative protein expression of hormone-sensitive lipase, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and low-density lipoprotein receptor (LDL-R) between CSC and SHC mice. However, relative protein expression of the scavenger receptor class B type 1 (SR-BI) was increased following CSC exposure. Moreover, analysis of plasma high-density lipoprotein-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) revealed increased LDL-C levels in CSC mice. Together with the pronounced increase in adrenal weight, evidently mediated by hyperplasia of adrenocortical cells, these data strongly indicate an enhanced adrenal availability of and capacity to mobilize cholesterol in chronic psychosocially-stressed mice, contributing to their increased in vivo corticosterone response during acute heterotypic stressor exposure.
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Affiliation(s)
- Andrea M Füchsl
- Department of Behavioural and Molecular Neurobiology, University of Regensburg , Regensburg, Germany
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27
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Yang XP, Amar MJ, Vaisman B, Bocharov AV, Vishnyakova TG, Freeman LA, Kurlander RJ, Patterson AP, Becker LC, Remaley AT. Scavenger receptor-BI is a receptor for lipoprotein(a). J Lipid Res 2013; 54:2450-7. [PMID: 23812625 DOI: 10.1194/jlr.m038877] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Scavenger receptor class B type I (SR-BI) is a multi-ligand receptor that binds a variety of lipoproteins, including high density lipoprotein (HDL) and low density lipoprotein (LDL), but lipoprotein(a) [Lp(a)] has not been investigated as a possible ligand. Stable cell lines (HEK293 and HeLa) expressing human SR-BI were incubated with protein- or lipid-labeled Lp(a) to investigate SR-BI-dependent Lp(a) cell association. SR-BI expression enhanced the association of both (125)I- and Alexa Fluor-labeled protein from Lp(a). By confocal microscopy, SR-BI was also found to promote the internalization of fluorescent lipids (BODIPY-cholesteryl ester (CE)- and DiI-labeled) from Lp(a), and by immunocytochemistry the cellular internalization of apolipoprotein(a) and apolipoprotein B. When dual-labeled ((3)H-cholesteryl ether,(125)I-protein) Lp(a) was added to cells expressing SR-BI, there was a greater relative increase in lipid uptake over protein, indicating that SR-BI mediates selective lipid uptake from Lp(a). Compared with C57BL/6 control mice, transgenic mice overexpressing human SR-BI in liver were found to have increased plasma clearance of (3)H-CE-Lp(a), whereas mouse scavenger receptor class B type I knockout (Sr-b1-KO) mice had decreased plasma clearance (fractional catabolic rate: 0.63 ± 0.08/day, 1.64 ± 0.62/day, and 4.64 ± 0.40/day for Sr-b1-KO, C57BL/6, and human scavenger receptor class B type I transgenic mice, respectively). We conclude that Lp(a) is a novel ligand for SR-BI and that SR-BI mediates selective uptake of Lp(a)-associated lipids.
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Affiliation(s)
- Xiao-Ping Yang
- Cardiology Division, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Hu Z, Shen WJ, Kraemer FB, Azhar S. MicroRNAs 125a and 455 repress lipoprotein-supported steroidogenesis by targeting scavenger receptor class B type I in steroidogenic cells. Mol Cell Biol 2012; 32:5035-45. [PMID: 23045399 PMCID: PMC3510537 DOI: 10.1128/mcb.01002-12] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 10/03/2012] [Indexed: 12/25/2022] Open
Abstract
We sought to identify and characterize microRNA (miRNAs) that posttranscriptionally regulate the expression of scavenger receptor class B type I (SR-BI) and SR-BI-linked selective high-density lipoprotein (HDL) cholesteryl ester (CE) transport and steroidogenesis. Four miRNAs (miRNA-125a, miRNA-125b, miRNA-145, and miRNA-455) with a potential to regulate SR-BI were identified in silico and validated by quantitative real-time PCR (qRT-PCR), Western blot analysis, and SR-BI 3' untranslated region (UTR) reporter assays. In vitro treatment of primary rat granulosa cells and MLTC-1 cells with cyclic AMP (cAMP) or in vivo treatment of rat adrenals with adrenocorticotropic hormone (ACTH) decreased the expression of miRNA-125a, miRNA-125b, and miRNA-455 and reciprocally increased SR-BI expression. Using luciferase constructs containing the 3' untranslated region of SR-BI combined with miRNA overexpression and mutagenesis, we have provided evidence that steroidogenic SR-BI is a direct target of miRNA-125a and miRNA-455. Moreover, the transfection of Leydig tumor cells with precursor miRNA 125a (pre-miRNA-125a) or pre-miRNA-455 resulted in the suppression of SR-BI at both the transcript and protein levels and reduced selective HDL CE uptake and HDL-stimulated progesterone production. Transfection of liver Hepa 1-6 cells with pre-miRNA-125a significantly reduced SR-BI expression and its selective transport function. In contrast, overexpression of miRNA-145 did not affect SR-BI expression or selective HDL CE uptake mediated by SR-BI in steroidogenic cell lines. These data suggest that a trophic hormone and cAMP inversely regulate the expression of SR-BI and miRNA-125a and miRNA-455 in steroidogenic tissues/cells and that both miRNA-125a and miRNA-455, by targeting steroidogenic SR-BI, negatively regulate selective HDL CE uptake and HDL CE-supported steroid hormone production.
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Affiliation(s)
- Zhigang Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, USA
- Division of Endocrinology
| | - Wen-Jun Shen
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, USA
- Division of Endocrinology
| | - Fredric B. Kraemer
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, USA
- Division of Endocrinology
| | - Salman Azhar
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California, USA
- Division of Gastroenterology and Hepatology, Stanford University, Stanford, California, USA
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29
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Li SPY, Tang TSM, Yiu KSM, Lo KKW. Cyclometalated Iridium(III)-Polyamine Complexes with Intense and Long-Lived Multicolor Phosphorescence: Synthesis, Crystal Structure, Photophysical Behavior, Cellular Uptake, and Transfection Properties. Chemistry 2012; 18:13342-54. [DOI: 10.1002/chem.201200979] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Indexed: 12/17/2022]
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30
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Shen WJ, Zaidi SK, Patel S, Cortez Y, Ueno M, Azhar R, Azhar S, Kraemer FB. Ablation of vimentin results in defective steroidogenesis. Endocrinology 2012; 153:3249-57. [PMID: 22535769 PMCID: PMC3380307 DOI: 10.1210/en.2012-1048] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In steroidogenic tissues, cholesterol must be transported to the inner mitochondrial membrane to be converted to pregnenolone as the first step of steroidogenesis. Whereas steroidogenic acute regulatory protein has been shown to be responsible for the transport of cholesterol from the outer to the inner mitochondrial membrane, the process of how cholesterol moves to mitochondria from the cytoplasm is not clearly defined. The involvement of the cytoskeleton has been suggested; however, no specific mechanism has been confirmed. In this paper, using genetic ablation of an intermediate filament protein in mice, we present data demonstrating a marked defect in adrenal and ovarian steroidogenesis in the absence of vimentin. Cosyntropin-stimulated corticosterone production is decreased 35 and 50% in male and female Vimentin null (Vim(-/-)) mice, respectively, whereas progesterone production is decreased 70% in female Vim(-/-) mice after pregnant mare's serum gonadotropin and human chorionic gonadotropin stimulation, but no abnormalities in human chorionic gonadotropin-stimulated testosterone production is observed in male Vim(-/-) mice. These defects in steroid production are also seen in isolated adrenal and granulosa cells in vitro. Further studies show a defect in the movement of cholesterol from the cytosol to mitochondria in Vim(-/-) cells. Because the mobilization of cholesterol from lipid droplets and its transport to mitochondria is a preferred pathway for the initiation of steroid production in the adrenal and ovary but not the testis and vimentin is a droplet-associated protein, our results suggest that vimentin is involved in the movement of cholesterol from its storage in lipid droplets to mitochondria for steroidogenesis.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California 94304, USA
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31
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Hu J, Zhang Z, Shen WJ, Nomoto A, Azhar S. Differential roles of cysteine residues in the cellular trafficking, dimerization, and function of the high-density lipoprotein receptor, SR-BI. Biochemistry 2011; 50:10860-75. [PMID: 22097902 DOI: 10.1021/bi201264y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The scavenger receptor, class B, type I (SR-BI) binds high-density lipoprotein (HDL) and mediates selective delivery of cholesteryl esters (CEs) to the liver and steroidogenic cells of the adrenal glands and gonads. Although it is clear that the large extracellular domain (ECD) of SR-BI binds HDL, the role of ECD in the selective HDL-CE transport remains poorly understood. In this study, we used a combination of mutational and chemical approaches to systematically evaluate the contribution of cysteine residues, especially six cysteine residues of ECD, in SR-BI-mediated selective HDL-CE uptake, intracellular trafficking, and SR-BI dimerization. Pretreatment of SR-BI-overexpressing COS-7 cells with a disulfide (S-S) bond reducing agent, β-mercaptoethanol (100 mM) or dithiothreitol (DTT) (10 mM), modestly but significantly impaired SR-BI-mediated selective HDL-CE uptake. Treatment of SR-BI-overexpressing COS-7 cells with the optimal doses of membrane permeant alkyl methanethiosulfonate (MTS) reagents, positively charged MTSEA or neutral MMTS, that specifically react with the free sulfhydryl group of cysteine reduced the rate of SR-BI-mediated selective HDL-CE uptake, indicating that certain intracellular free cysteine residues may also be critically involved in the selective cholesterol transport process. In contrast, use of membrane impermeant MTS reagent, positively charged MTSET and negatively charged MTSES, showed no such effect. Next, the importance of eight cysteine residues in SR-BI expression, cell surface expression, dimer formation, and selective HDL-derived CE transport was evaluated. These cysteine residues were replaced either singly or in pairs with serine, and the mutant SR-BIs were expressed in either COS-7 or CHO cells. Four mutations, C280S, C321S, C323S, and C334S, of the ECD, either singly or in various pair combinations, resulted in significant decreases in SR-BI (HDL) binding activity, selective CE uptake, and trafficking to the cell surface. Surprisingly, we found that mutation of the two remaining cysteine residues, C251 and C384 of the ECD, had no effect on either SR-BI expression or function. Other cysteine mutations and substitutions were also without effect. Western blot data indicated that single and double mutations at C280, C321, C323, and C334 residues strongly favor dimer formation. However, they are rendered nonfunctional presumably because of mutation-induced formation of aberrant disulfide linkages resulting in inhibition of optimal HDL binding and, thus, selective HDL-CE uptake. These results provide novel insights into the functional role of four cysteine residues, C280, C321, C323, and C334, of the SR-BI ECD in SR-BI expression and trafficking to the cell surface, its dimerization, and associated selective CE transport function.
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Affiliation(s)
- Jie Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304, United States
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32
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Louie MW, Fong TTH, Lo KKW. Luminescent Rhenium(I) Polypyridine Fluorous Complexes as Novel Trifunctional Biological Probes. Inorg Chem 2011; 50:9465-71. [DOI: 10.1021/ic201143f] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Man-Wai Louie
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Tommy Tsz-Him Fong
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
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33
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Nieland TJ, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011; 50:1818-30. [PMID: 21254782 PMCID: PMC3065119 DOI: 10.1021/bi101657j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J.F. Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
- Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, MA 02142
| | - Shangzhe Xu
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Marsha Penman
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Monty Krieger
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
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34
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Nieland TJF, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011. [PMID: 21254782 DOI: 10.1021/bi1011657j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J F Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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35
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Synthesis, properties, and live-cell imaging studies of luminescent cyclometalated iridium(III) polypyridine complexes containing two or three biotin pendants. Inorg Chem 2010; 48:6011-25. [PMID: 19480459 DOI: 10.1021/ic900412n] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three luminescent cyclometalated iridium(III) bis-biotin complexes [Ir(N(wedge)C)(2)(N(wedge)N)](PF(6)) (HN(wedge)C = 2-(4-(N-(6-(biotinamido)hexyl)aminomethyl)phenyl)pyridine, HppyC6B, N(wedge)N = 2,2'-bipyridine, bpy (1); HN(wedge)C = 2-phenylpyridine, Hppy, N(wedge)N = 4,4'-bis((2-(biotinamido)ethyl)aminocarbonyl)-2,2'-bipyridine, bpyC2B2 (2); HN(wedge)C = Hppy, N(wedge)N = 4,4'-bis((2-((6-(biotinamido)hexanoyl)amino)ethyl)aminocarbonyl)-2,2'-bipyridine, bpyC2C6B2 (3)) and one tris-biotin complex [Ir(ppyC6B)(2)(bpyC6B)](PF(6)) (bpyC6B = 4-((6-(biotinamido)hexyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine) (4) have been synthesized and characterized. The biotin-free complex [Ir(ppy)(2)(bpyC4)](PF(6)) (bpyC4 = 4,4'-bis(n-butylaminocarbonyl)-2,2'-bipyridine) (5) has also been prepared for comparison studies. Upon photoexcitation, all the complexes displayed intense and long-lived greenish-yellow to red triplet metal-to-ligand charge-transfer ((3)MLCT) (dpi (Ir) --> pi*(N(wedge)N)) emission in fluid solutions at room temperature and in low-temperature glass. Cyclic voltammetric studies revealed iridium(IV/III) oxidation at about +1.21 to + 1.29 V and diimine-based reductions at about -1.07 to -1.39 V versus SCE. The interactions of the bis-biotin and tris-biotin complexes with avidin have been studied by 4'-hydroxyazobenzene-2-carboxylic acid (HABA) assays, emission titrations, and dissociation assays. The possibility of these complexes as cross-linkers for avidin has been examined by microscopy studies using avidin-conjugated green fluororescent microspheres and size-exclusion HPLC analysis. Utilization of these luminescent iridium(III) biotin complexes in signal amplification has been demonstrated using avidin-coated nonfluorescent microspheres and complex 3 as an example. Additionally, the lipophilicity of all the complexes has been determined by reversed-phase HPLC. The cytotoxicity of these iridium(III) complexes toward the human cervix epithelioid carcinoma (HeLa) cell line has been evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assays. Furthermore, the cellular uptake of the complexes has been examined by ICP-MS, laser-scanning confocal microscopy, and flow cytometry.
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Lee PK, Liu HW, Yiu SM, Louie MW, Lo KKW. Luminescent cyclometallated iridium(III) bis(quinolylbenzaldehyde) diimine complexes--synthesis, photophysics, electrochemistry, protein cross-linking properties, cytotoxicity and cellular uptake. Dalton Trans 2010; 40:2180-9. [PMID: 20717588 DOI: 10.1039/c0dt00501k] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Four new luminescent cyclometallated iridium(III) bis(quinolylbenzaldehyde) diimine complexes [Ir(qba)(2)(N⁁N)](PF(6)) (Hqba = 4-(2-quinolyl)benzaldehyde, N⁁N = 2,2'-bipyridine, bpy (1); 1,10-phenanthroline, phen (2); 3,4,7,8-tetramethyl-1,10-phenanthroline, Me(4)-phen (3); 4,7-diphenyl-1,10-phenanthroline, Ph(2)-phen (4)) have been synthesised and characterised, and their electronic absorption, emission and electrochemical properties investigated. The X-ray crystal structures of complexes 1 and 2 have been determined. Upon irradiation, complexes 1-4 exhibited intense and long-lived orange-yellow emission in fluid solutions at 298 K and in alcohol glass at 77 K. The emission has been assigned to a triplet intra-ligand ((3)IL) excited state associated with the qba ligand, probably with mixing of some triplet metal-to-ligand charge-transfer ((3)MLCT) (dπ(Ir) →π*(qba)) character. Reductive amination reactions of complexes 1-4 with the protein bovine serum albumin (BSA) afforded the bioconjugates 1-BSA-4-BSA, respectively. Upon photoexcitation, these bioconjugates displayed intense and long-lived (3)MLCT (dπ(Ir) →π*(N⁁C)) emission in aqueous buffer at 298 K. The cross-linked nature of the Ir-BSA bioconjugates has been verified by SDS-PAGE. Additionally, the cytotoxicity of the complexes towards human cervix epithelioid carcinoma (HeLa) cells has been examined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assays, and the cellular uptake of complex 4 has been investigated by laser-scanning confocal microscopy and flow cytometry.
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Affiliation(s)
- Pui-Kei Lee
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, People's Republic of China
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Cellular cholesterol delivery, intracellular processing and utilization for biosynthesis of steroid hormones. Nutr Metab (Lond) 2010; 7:47. [PMID: 20515451 PMCID: PMC2890697 DOI: 10.1186/1743-7075-7-47] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 06/01/2010] [Indexed: 11/28/2022] Open
Abstract
Steroid hormones regulate diverse physiological functions such as reproduction, blood salt balance, maintenance of secondary sexual characteristics, response to stress, neuronal function and various metabolic processes. They are synthesized from cholesterol mainly in the adrenal gland and gonads in response to tissue-specific tropic hormones. These steroidogenic tissues are unique in that they require cholesterol not only for membrane biogenesis, maintenance of membrane fluidity and cell signaling, but also as the starting material for the biosynthesis of steroid hormones. It is not surprising, then, that cells of steroidogenic tissues have evolved with multiple pathways to assure the constant supply of cholesterol needed to maintain optimum steroid synthesis. The cholesterol utilized for steroidogenesis is derived from a combination of sources: 1) de novo synthesis in the endoplasmic reticulum (ER); 2) the mobilization of cholesteryl esters (CEs) stored in lipid droplets through cholesteryl ester hydrolase; 3) plasma lipoprotein-derived CEs obtained by either LDL receptor-mediated endocytic and/or SR-BI-mediated selective uptake; and 4) in some cultured cell systems from plasma membrane-associated free cholesterol. Here, we focus on recent insights into the molecules and cellular processes that mediate the uptake of plasma lipoprotein-derived cholesterol, events connected with the intracellular cholesterol processing and the role of crucial proteins that mediate cholesterol transport to mitochondria for its utilization for steroid hormone production. In particular, we discuss the structure and function of SR-BI, the importance of the selective cholesterol transport pathway in providing cholesterol substrate for steroid biosynthesis and the role of two key proteins, StAR and PBR/TSO in facilitating cholesterol delivery to inner mitochondrial membrane sites, where P450scc (CYP11A) is localized and where the conversion of cholesterol to pregnenolone (the common steroid precursor) takes place.
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Intracellular lipid droplets contain dynamic pools of sphingomyelin: ADRP binds phospholipids with high affinity. Lipids 2010; 45:465-77. [PMID: 20473576 DOI: 10.1007/s11745-010-3424-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 04/23/2010] [Indexed: 12/11/2022]
Abstract
During the last several years, intracellular lipid droplets have become the focus of intense study. No longer an inert bystander, the lipid droplet is now known as a dynamic organelle contributing lipids to many cellular events. However, while the dynamics of cholesterol efflux from both the plasma membrane and lipid droplets have been studied, less is known regarding the efflux of sphingomyelin from these membranes. In order to address this issue, sphingomyelin efflux kinetics and binding affinities from different intracellular pools were examined. When compared to the plasma membrane, lipid droplets had a smaller exchangeable sphingomyelin efflux pool and the time required to efflux that pool was significantly shorter. Fluorescence binding assays revealed that proteins in the plasma membrane and lipid droplet pool bound sphingomyelin with high affinity. Further characterization identified adipose differentiation-related protein (ADRP) as one of the sphingomyelin binding proteins in the lipid droplet fraction and revealed that ADRP demonstrated saturable binding to 6-((N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-hexanoyl)sphingosyl-phosphocholine (NBD-sphingomyelin) and also 2-(6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine (NBD-phosphatidylcholine) with binding affinities in the nanomolar range. Taken together, these results suggest that lipid droplet associated proteins such as ADRP may play a significant role in regulating the intracellular distribution of phospholipids and lipids in general. Overall, insights from the present work suggest new and important roles for lipid droplets and ADRP in phospholipid metabolism.
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Leung SK, Kwok KY, Zhang KY, Lo KKW. Design of Luminescent Biotinylation Reagents Derived from Cyclometalated Iridium(III) and Rhodium(III) Bis(pyridylbenzaldehyde) Complexes. Inorg Chem 2010; 49:4984-95. [DOI: 10.1021/ic100092d] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Siu-Kit Leung
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Karen Ying Kwok
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Kenneth Yin Zhang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
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Fujimoto VY, Kane JP, Ishida BY, Bloom MS, Browne RW. High-density lipoprotein metabolism and the human embryo. Hum Reprod Update 2010; 16:20-38. [PMID: 19700490 DOI: 10.1093/humupd/dmp029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND High-density lipoprotein (HDL) appears to be the dominant lipoprotein particle in human follicular fluid (FF). The reported anti-atherogenic properties of HDL have been attributed in part to reverse cholesterol transport. The discoveries of the scavenger receptor class B type I (SR-BI) and the ATP-binding cassette A1 lipid (ABCA1) transporter have generated studies aimed at unraveling the pathways of HDL biogenesis, remodeling and catabolism. The production of SR-BI and ABCA1 knockout mice as well as other lipoprotein metabolism-associated mutants has resulted in reduced or absent fertility, leading us to postulate the existence of a human hepatic-ovarian HDL-associated axis of fertility. Here, we review an evolving literature on the role of HDL metabolism on mammalian fertility and oocyte development. METHODS An extensive online search was conducted of published articles relevant to the section topics discussed. All relevant English language articles contained in Pubmed/Medline, with no specific time frame for publication, were considered for this narrative review. Cardiovascular literature was highly cited due to the wealth of relevant knowledge on HDL metabolism, and the dearth thereof in the reproductive field. RESULTS Various vertebrate models demonstrate a role for HDL in embryo development and fertility. In our clinical studies, FF levels of HDL cholesterol and apolipoprotein AI levels were negatively associated with embryo fragmentation, but not with embryo cell cleavage rate. However, the HDL component, paraoxonase 1 arylesterase activity, was positively associated with embryo cell cleavage rate. CONCLUSIONS HDL contributes to intra-follicular cholesterol homeostasis which appears to be important for successful oocyte and embryo development.
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Affiliation(s)
- Victor Y Fujimoto
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California at San Francisco, San Francisco, CA 94115-0916, USA.
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Lo KKW. Exploitation of Luminescent Organometallic Rhenium(I) and Iridium(III) Complexes in Biological Studies. TOP ORGANOMETAL CHEM 2010. [DOI: 10.1007/3418_2009_3] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Simard P, Leroux JC. pH-sensitive immunoliposomes specific to the CD33 cell surface antigen of leukemic cells. Int J Pharm 2009; 381:86-96. [PMID: 19446624 DOI: 10.1016/j.ijpharm.2009.05.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/09/2009] [Accepted: 05/07/2009] [Indexed: 10/20/2022]
Abstract
A promising avenue in cancer therapy using liposomal formulations is the combination of site-specific delivery with triggered drug release. The use of trigger mechanisms in liposomes could be relevant for drugs susceptible to lysosomal hydrolytic/enzymatic degradation. Here, we propose a polymeric pH-sensitive liposome system that is designed to release its content inside the endosomes through a polymer structural change following receptor-mediated internalization. Specifically, pH-sensitive immunoliposomes (ILs) were obtained by including a terminally alkylated copolymer of N-isopropylacrylamide (NIPAM) in the liposome bilayer and by coupling the anti-CD33 monoclonal antibody to target leukemic cells. In vitro release of encapsulated fluorescent probes and cytosine arabinoside (ara-C) revealed that pH-sensitivity of the vector was retained in the presence of the antibody upon incubation in plasma. Flow cytometry and confocal microscopy analyses demonstrated that the pH-sensitive ILs were efficiently internalized by various CD33+ leukemic cell lines while limited interaction was found for liposomes decorated with an isotype-matched control antibody. Finally, the pH-sensitive ILs-CD33 formulation exhibited the highest cytotoxicity against HL60 cells, confirming the role of the NIPAM copolymer in promoting the escape of intact ara-C in the endosomes. These results suggest that this pH-sensitive liposomal formulation could be beneficial in the treatment of acute myeloid leukemia.
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Affiliation(s)
- Pierre Simard
- Canada Research Chair in Drug Delivery, Faculty of Pharmacy, University of Montreal, P.C. 6128 Downtown Station, Montreal (Qc), Canada H3C 3J7
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Lau JSY, Lee PK, Tsang KHK, Ng CHC, Lam YW, Cheng SH, Lo KKW. Luminescent Cyclometalated Iridium(III) Polypyridine Indole Complexes—Synthesis, Photophysics, Electrochemistry, Protein-Binding Properties, Cytotoxicity, and Cellular Uptake. Inorg Chem 2008; 48:708-18. [DOI: 10.1021/ic801818x] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jason Shing-Yip Lau
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Pui-Kei Lee
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Keith Hing-Kit Tsang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Cyrus Ho-Cheong Ng
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Yun-Wah Lam
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Shuk-Han Cheng
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
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Lo KKW, Lee PK, Lau JSY. Synthesis, Characterization, and Properties of Luminescent Organoiridium(III) Polypyridine Complexes Appended with an Alkyl Chain and Their Interactions with Lipid Bilayers, Surfactants, and Living Cells. Organometallics 2008. [DOI: 10.1021/om800212t] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Pui-Kei Lee
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Jason Shing-Yip Lau
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
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Murphy G, Rouse RL, Polk WW, Henk WG, Barker SA, Boudreaux MJ, Floyd ZE, Penn AL. Combustion-Derived Hydrocarbons Localize to Lipid Droplets in Respiratory Cells. Am J Respir Cell Mol Biol 2008; 38:532-40. [DOI: 10.1165/rcmb.2007-0204oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Diamanti-Kandarakis E, Argyrakopoulou G, Economou F, Kandaraki E, Koutsilieris M. Defects in insulin signaling pathways in ovarian steroidogenesis and other tissues in polycystic ovary syndrome (PCOS). J Steroid Biochem Mol Biol 2008; 109:242-6. [PMID: 18440223 DOI: 10.1016/j.jsbmb.2008.03.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age today. Women with PCOS often demonstrate defective ovarian steroid biosynthesis and present with hyperandrogenemia. Moreover, 50-70% of PCOS women are insulin resistant and hyperinsulinemic. Insulin acts on the ovary via its own receptor and interacts with gonadotrophins, modulating steroidogenesis. The precise role of insulin and the molecular mechanisms that take place are not yet completely explicated. This review will be focused on insulin's action on the ovary and other target tissues, describing the intracellular signaling pathways implicated in steroidogenesis and their defects in women with PCOS.
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Affiliation(s)
- Evanthia Diamanti-Kandarakis
- Endocrine Section, First Department of Internal Medicine, University of Athens Medical School, 17 Ag. Thoma, Goudi 11527, Athens, Greece.
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Lo KKW, Lee TKM, Lau JSY, Poon WL, Cheng SH. Luminescent Biological Probes Derived from Ruthenium(II) Estradiol Polypyridine Complexes. Inorg Chem 2007; 47:200-8. [DOI: 10.1021/ic701735q] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
| | - Terence Kwok-Ming Lee
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
| | - Jason Shing-Yip Lau
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
| | - Wing-Lin Poon
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
| | - Shuk-Han Cheng
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
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Kheirolomoom A, Ferrara KW. Cholesterol transport from liposomal delivery vehicles. Biomaterials 2007; 28:4311-20. [PMID: 17610949 PMCID: PMC2043118 DOI: 10.1016/j.biomaterials.2007.06.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 06/05/2007] [Indexed: 01/15/2023]
Abstract
Rapid internalization of drugs from delivery vehicles via non-endocytotic pathways is an important goal. The transport of imaging probes attached to cholesterol and introduced via a liposomal formulation is considered here, in order to evaluate the intracellular distribution and kinetics of small molecular cargo that might be attached to cholesterol or phospholipids. The internalization efficiencies of two fluorescent cholesterol analogues, one carrying a fluorophore on the head of the cholesterol molecule 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-dodecanoate (BODIPY)-cholesteryl ester (CE) (BODIPY-CE) and the other on the tail (25-[N-[(7-nitro-2-1,3-benzoxadiazol-4-yl)-methyl]amino]-27-norcholesterol (NBD-cholesterol)), were compared with those of other phospholipid molecules (NBD-phosphatidylcholine (PC) and NBD-phosphatidylethanolamine (PE)) using a liposomal formulation (1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 85.5 M%; 1,2 distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2k), 9.5 M%; fluorescent analogue, 5 M%). The rate and transfer efficiency were NBD-cholesterol>BODIPY-CE>NBD-PC>NBD-PE. NBD-cholesterol, delivered by liposomes with an average diameter of 100 nm, localized in the perinuclear region and lipid storage droplets, with transfer observed in as little as 5 min. NBD-cholesterol transport was approximately constant with time, suggesting a unidirectional mode of entry. In the absence of PEG within the liposome, the transfer rate decreased. Filipin, a caveolae-blocking agent, caused 70% inhibition of cholesterol internalization in treated cells, suggesting that cholesterol internalization follows a caveolae-mediated pathway.
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Affiliation(s)
| | - Katherine W. Ferrara
- *Corresponding author: Tel: (530) 754-9436. Fax: (530) 754-5739. E-mail address:
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Wüstner D. Fluorescent sterols as tools in membrane biophysics and cell biology. Chem Phys Lipids 2007; 146:1-25. [PMID: 17241621 DOI: 10.1016/j.chemphyslip.2006.12.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 12/05/2006] [Accepted: 12/18/2006] [Indexed: 12/26/2022]
Abstract
Cholesterol is an important constituent of cellular membranes playing a fundamental role in many biological processes. This sterol affects membrane permeability, lateral lipid organization, signal transduction and membrane trafficking. Intracellular sterol transport modes and pathways as well as the regulation of sterol metabolism and disposition in various tissues are areas of intense research. Progress is intimately linked to development and use of appropriate analogs, which closely mimic the properties of cholesterol while allowing to be detected by spectroscopic or microscopic methods. This review provides an overview of various fluorescent sterols used in membrane biophysics and cell biology including analogs of cholesterol and cholesteryl esters. Attention is paid to the natural fluorescent sterol dehydroergosterol (DHE). A survey of the many applications of DHE in biological research is presented. Special emphasis is on recent developments in fluorescence microscopy instrumentation to visualize DHE as an intrinsically fluorescent analog of cholesterol in living cells.
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Affiliation(s)
- Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Kraemer FB, Shen WJ, Patel S, Osuga JI, Ishibashi S, Azhar S. The LDL receptor is not necessary for acute adrenal steroidogenesis in mouse adrenocortical cells. Am J Physiol Endocrinol Metab 2007; 292:E408-12. [PMID: 16985254 DOI: 10.1152/ajpendo.00428.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Steroid hormones are synthesized using cholesterol as precursor. To determine the functional importance of the low density lipoprotein (LDL) receptor and hormone-sensitive lipase (HSL) in adrenal steroidogenesis, adrenal cells were isolated from control, HSL(-/-), LDLR(-/-), and double LDLR/HSL(-/-) mice. The endocytic and selective uptake of apolipoprotein E-free human high density lipoprotein (HDL)-derived cholesteryl esters did not differ among the mice, with selective uptake accounting for >97% of uptake. In contrast, endocytic uptake of either human LDL- or rat HDL-derived cholesteryl esters was reduced 80-85% in LDLR(-/-) and double-LDLR/HSL(-/-) mice. There were no differences in the selective uptake of either human LDL- or rat HDL-derived cholesteryl esters among the mice. Maximum corticosterone production induced by ACTH or dibutyryl cyclic AMP and lipoproteins was not altered in LDLR(-/-) mice but was reduced 80-90% in HSL(-/-) mice. Maximum corticosterone production was identical in HSL(-/-) and double-LDLR/HSL(-/-) mice. These findings suggest that, although the LDL receptor is responsible for endocytic delivery of cholesteryl esters from LDL and rat HDL to mouse adrenal cells, it appears to play a negligible role in the delivery of cholesterol for acute adrenal steroidogenesis in the mouse. In contrast, HSL occupies a vital role in adrenal steroidogenesis because of its link to utilization of selectively delivered cholesteryl esters from lipoproteins.
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