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Jensen L, Venkei ZG, Watase GJ, Bisai B, Pletcher S, Lee CY, Yamashita YM. me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline. J Cell Sci 2021; 134:269264. [PMID: 34164657 PMCID: PMC8325955 DOI: 10.1242/jcs.258757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/14/2021] [Indexed: 12/31/2022] Open
Abstract
Tissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important for maintaining the stem cell population, it is speculated that it underlies tumorigenesis. Therefore, this process must be tightly controlled. Here, we show that a translational regulator, me31B, plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.
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Affiliation(s)
- Lindy Jensen
- Life Sciences Institute, Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI 48109, USA
| | - Zsolt G Venkei
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02142, USA
| | - George J Watase
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Cambridge, MA 02142, USA
| | - Bitarka Bisai
- Life Sciences Institute, Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI 48109, USA
| | - Scott Pletcher
- Life Sciences Institute, Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI 48109, USA
| | - Cheng-Yu Lee
- Life Sciences Institute, Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI 48109, USA
| | - Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Cambridge, MA 02142, USA
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2
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Pletcher S. Neural Control of Healthy Aging in Drosophila Through Perceptive Experiences. Innov Aging 2020. [PMCID: PMC7743339 DOI: 10.1093/geroni/igaa057.2634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
We will describe how neurosensory circuits relate information about nutrition, danger, and mates to initiate rapid changes health and aging, including evolutionarily conserved neural signaling pathways and molecules that extend organism lifespan. These findings provoke the notion that aging may be considered a complex behavior that is acutely malleable, susceptible to sensory influences, and strictly controlled by coordinated sets of neurons.
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Affiliation(s)
- Scott Pletcher
- University of Michigan, Ann Arbor, Michigan, United States
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3
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Hahn O, Drews LF, Nguyen A, Tatsuta T, Gkioni L, Hendrich O, Zhang Q, Langer T, Pletcher S, Wakelam MJO, Beyer A, Grönke S, Partridge L. A nutritional memory effect counteracts benefits of dietary restriction in old mice. Nat Metab 2019; 1:1059-1073. [PMID: 31742247 PMCID: PMC6861129 DOI: 10.1038/s42255-019-0121-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dietary restriction (DR) during adulthood can greatly extend lifespan and improve metabolic health in diverse species. However, whether DR in mammals is still effective when applied for the first time at old age remains elusive. Here, we report results of a late-life DR switch experiment employing 800 mice, in which 24 months old female mice were switched from ad libitum (AL) to DR or vice versa. Strikingly, the switch from DR-to-AL acutely increases mortality, whereas the switch from AL-to-DR causes only a weak and gradual increase in survival, suggesting a memory of earlier nutrition. RNA-seq profiling in liver, brown (BAT) and white adipose tissue (WAT) demonstrate a largely refractory transcriptional and metabolic response to DR after AL feeding in fat tissue, particularly in WAT, and a proinflammatory signature in aged preadipocytes, which is prevented by chronic DR feeding. Our results provide evidence for a nutritional memory as a limiting factor for DR-induced longevity and metabolic remodeling of WAT in mammals.
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Affiliation(s)
- Oliver Hahn
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Cellular Networks and Systems Biology, CECAD, University of Cologne, Cologne, Germany
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Lisa F Drews
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - An Nguyen
- Inositide lab, The Babraham Institute, Cambridge, UK
| | - Takashi Tatsuta
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Lisonia Gkioni
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Oliver Hendrich
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Qifeng Zhang
- Inositide lab, The Babraham Institute, Cambridge, UK
| | - Thomas Langer
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Scott Pletcher
- Department of Molecular & Integrative Physiology and the Geriatrics Center, University of Michigan, Ann Arbor, USA
| | | | - Andreas Beyer
- Cellular Networks and Systems Biology, CECAD, University of Cologne, Cologne, Germany.
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
| | | | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Cologne, Germany.
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, UK.
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4
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Miller RA, Harrison DE, Astle CM, Fernandez E, Flurkey K, Han M, Javors MA, Li X, Nadon NL, Nelson JF, Pletcher S, Salmon AB, Sharp ZD, Van Roekel S, Winkleman L, Strong R. Rapamycin-mediated lifespan increase in mice is dose and sex dependent and metabolically distinct from dietary restriction. Aging Cell 2014; 13:468-77. [PMID: 24341993 PMCID: PMC4032600 DOI: 10.1111/acel.12194] [Citation(s) in RCA: 399] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2013] [Indexed: 01/07/2023] Open
Abstract
Rapamycin, an inhibitor of mTOR kinase, increased median lifespan of genetically heterogeneous mice by 23% (males) to 26% (females) when tested at a dose threefold higher than that used in our previous studies; maximal longevity was also increased in both sexes. Rapamycin increased lifespan more in females than in males at each dose evaluated, perhaps reflecting sexual dimorphism in blood levels of this drug. Some of the endocrine and metabolic changes seen in diet-restricted mice are not seen in mice exposed to rapamycin, and the pattern of expression of hepatic genes involved in xenobiotic metabolism is also quite distinct in rapamycin-treated and diet-restricted mice, suggesting that these two interventions for extending mouse lifespan differ in many respects.
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Affiliation(s)
- Richard A. Miller
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | | | | | - Elizabeth Fernandez
- Geriatric Research Education and Clinical Center and Research Service South Texas Veterans Health Care System San Antonio TX 78229 USA
| | | | - Melissa Han
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | - Martin A. Javors
- Department of Psychiatry The University of Texas Health Science Center at San Antonio San Antonio TX 78229 USA
| | - Xinna Li
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | - Nancy L. Nadon
- Division of Aging Biology National Institute on Aging Bethesda MD 20892 USA
| | - James F. Nelson
- Department of Physiology and Barshop Institute for Longevity and Aging Studies The University of Texas Health Science Center at San Antonio San Antonio TX 78229 USA
| | - Scott Pletcher
- Department of Molecular and Integrative Physiology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | - Adam B. Salmon
- Barshop Institute for Longevity and Aging Studies University of Texas Health Science Center San Antonio San Antonio TX 78245 USA
| | - Zelton Dave Sharp
- Barshop Institute for Longevity and Aging Studies University of Texas Health Science Center San Antonio San Antonio TX 78245 USA
- Department of Molecular Medicine University of Texas Health Science Center San Antonio San Antonio TX 78245 USA
| | - Sabrina Van Roekel
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | - Lynn Winkleman
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109 USA
| | - Randy Strong
- Geriatric Research Education and Clinical Center and Research Service South Texas Veterans Health Care System San Antonio TX 78229 USA
- Barshop Institute for Longevity and Aging Studies University of Texas Health Science Center San Antonio San Antonio TX 78245 USA
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Harrison DE, Strong R, Allison DB, Ames BN, Astle CM, Atamna H, Fernandez E, Flurkey K, Javors MA, Nadon NL, Nelson JF, Pletcher S, Simpkins JW, Smith D, Wilkinson JE, Miller RA. Acarbose, 17-α-estradiol, and nordihydroguaiaretic acid extend mouse lifespan preferentially in males. Aging Cell 2014; 13:273-82. [PMID: 24245565 PMCID: PMC3954939 DOI: 10.1111/acel.12170] [Citation(s) in RCA: 282] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2013] [Indexed: 01/09/2023] Open
Abstract
Four agents — acarbose (ACA), 17-α-estradiol (EST), nordihydroguaiaretic acid (NDGA), and methylene blue (MB) — were evaluated for lifespan effects in genetically heterogeneous mice tested at three sites. Acarbose increased male median lifespan by 22% (P < 0.0001), but increased female median lifespan by only 5% (P = 0.01). This sexual dimorphism in ACA lifespan effect could not be explained by differences in effects on weight. Maximum lifespan (90th percentile) increased 11% (P < 0.001) in males and 9% (P = 0.001) in females. EST increased male median lifespan by 12% (P = 0.002), but did not lead to a significant effect on maximum lifespan. The benefits of EST were much stronger at one test site than at the other two and were not explained by effects on body weight. EST did not alter female lifespan. NDGA increased male median lifespan by 8–10% at three different doses, with P-values ranging from 0.04 to 0.005. Females did not show a lifespan benefit from NDGA, even at a dose that produced blood levels similar to those in males, which did show a strong lifespan benefit. MB did not alter median lifespan of males or females, but did produce a small, statistically significant (6%, P = 0.004) increase in female maximum lifespan. These results provide new pharmacological models for exploring processes that regulate the timing of aging and late-life diseases, and in particular for testing hypotheses about sexual dimorphism in aging and health.
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Affiliation(s)
| | - Randy Strong
- Barshop Institute for Longevity and Aging Studies The University of Texas Health Science Center at San Antonio San Antonio TX 78245USA
- Geriatric Research, Education and Clinical Center South Texas Veterans Health Care System San Antonio TX 78229USA
- Research Service South Texas Veterans Health Care System San Antonio TX 78229USA
- Department of Pharmacology The University of Texas Health Science Center at San Antonio San Antonio TX 78229USA
| | - David B. Allison
- Department of Biostatistics University of Alabama at Birmingham Birmingham AL 35294USA
| | - Bruce N. Ames
- Children's Hospital Oakland Research Institute 5700 Martin Luther King Jr. Way Oakland CA 94609‐1673USA
| | | | - Hani Atamna
- Children's Hospital Oakland Research Institute 5700 Martin Luther King Jr. Way Oakland CA 94609‐1673USA
| | - Elizabeth Fernandez
- Barshop Institute for Longevity and Aging Studies The University of Texas Health Science Center at San Antonio San Antonio TX 78245USA
- Geriatric Research, Education and Clinical Center South Texas Veterans Health Care System San Antonio TX 78229USA
- Research Service South Texas Veterans Health Care System San Antonio TX 78229USA
- Department of Pharmacology The University of Texas Health Science Center at San Antonio San Antonio TX 78229USA
| | | | - Martin A. Javors
- Barshop Institute for Longevity and Aging Studies The University of Texas Health Science Center at San Antonio San Antonio TX 78245USA
- Department of Psychiatry The University of Texas Health Science Center at San Antonio San Antonio TX 78229USA
| | - Nancy L. Nadon
- Division of Aging Biology National Institute on Aging Bethesda MD 20892USA
| | - James F. Nelson
- Barshop Institute for Longevity and Aging Studies The University of Texas Health Science Center at San Antonio San Antonio TX 78245USA
- Department of Physiology The University of Texas Health Science Center at San Antonio San Antonio TX 78229USA
| | - Scott Pletcher
- Department of Molecular and Integrative Physiology, and Geriatrics Center University of Michigan Ann Arbor MI 48109USA
| | - James W. Simpkins
- Department of Pharmacology & Neuroscience University of North Texas Health Science Center Fort Worth TX 76107USA
| | - Daniel Smith
- Department of Nutrition Sciences University of Alabama at Birmingham Birmingham AL 35294USA
| | - J. Erby Wilkinson
- Unit for Laboratory Animal Medicine University of Michigan School of Medicine Ann Arbor MI 48109USA
| | - Richard A. Miller
- Department of Pathology and Geriatrics Center University of Michigan Ann Arbor MI 48109USA
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Soibam B, Mann M, Liu L, Tran J, Lobaina M, Kang YY, Gunaratne GH, Pletcher S, Roman G. Open-field arena boundary is a primary object of exploration for Drosophila. Brain Behav 2012; 2:97-108. [PMID: 22574279 PMCID: PMC3345355 DOI: 10.1002/brb3.36] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 11/29/2011] [Accepted: 12/14/2011] [Indexed: 11/10/2022] Open
Abstract
Drosophila adults, when placed into a novel open-field arena, initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity and spend a majority of time near the arena edge, executing motions along the walls. In order to determine the environmental features that are responsible for the initial high activity and wall-following behavior exhibited during exploration, we examined wild-type and visually impaired mutants in arenas with different vertical surfaces. These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity. In circular arenas, Drosophila mostly move in trajectories with low turn angles. Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference. In an hourglass-shaped arena with convex-angled walls that forced a straight versus wall-following choice, the simulation with constrained turn angles predicted general movement across a central gap, whereas Drosophila tend to follow the wall. Hence, low turn angled movement does not drive the boundary preference. Lastly, visually impaired Drosophila demonstrate a defect in attenuation of the elevated initial activity. Interestingly, the visually impaired w(1118) activity decay defect can be rescued by increasing the contrast of the arena's edge, suggesting that the activity decay relies on visual detection of the boundary. The arena boundary is, therefore, a primary object of exploration for Drosophila.
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Affiliation(s)
- Benjamin Soibam
- Department of Computer Science, University of HoustonHouston, Texas 77204
| | - Monica Mann
- Department of Biology and Biochemistry, University of HoustonHouston, Texas 77204
| | - Lingzhi Liu
- Department of Biology and Biochemistry, University of HoustonHouston, Texas 77204
| | - Jessica Tran
- Department of Biology and Biochemistry, University of HoustonHouston, Texas 77204
| | - Milena Lobaina
- Department of Natural Sciences, University of Houston DowntownHouston, Texas 77002
| | - Yuan Yuan Kang
- Department of Natural Sciences, University of Houston DowntownHouston, Texas 77002
| | | | - Scott Pletcher
- University of Michigan Geriatrics Center, Department of Molecular and Integrative Physiology, University of MichiganAnn Arbor, Michigan 49108
| | - Gregg Roman
- Department of Biology and Biochemistry, University of HoustonHouston, Texas 77204
- Biology of Behavior Institute, University of HoustonHouston, Texas 77204
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Miller RA, Harrison DE, Astle CM, Baur JA, Boyd AR, de Cabo R, Fernandez E, Flurkey K, Javors MA, Nelson JF, Orihuela CJ, Pletcher S, Sharp ZD, Sinclair D, Starnes JW, Wilkinson JE, Nadon NL, Strong R. Rapamycin, but not resveratrol or simvastatin, extends life span of genetically heterogeneous mice. J Gerontol A Biol Sci Med Sci 2010; 66:191-201. [PMID: 20974732 DOI: 10.1093/gerona/glq178] [Citation(s) in RCA: 642] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Rapamycin was administered in food to genetically heterogeneous mice from the age of 9 months and produced significant increases in life span, including maximum life span, at each of three test sites. Median survival was extended by an average of 10% in males and 18% in females. Rapamycin attenuated age-associated decline in spontaneous activity in males but not in females. Causes of death were similar in control and rapamycin-treated mice. Resveratrol (at 300 and 1200 ppm food) and simvastatin (12 and 120 ppm) did not have significant effects on survival in male or female mice. Further evaluation of rapamycin's effects on mice is likely to help delineate the role of the mammalian target of rapamycin complexes in the regulation of aging rate and age-dependent diseases and may help to guide a search for drugs that retard some or all of the diseases of aging.
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Affiliation(s)
- Richard A Miller
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109-2200, USA.
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Pletcher S. 01 Teaching Medical Professionals about Community Resources: The MSU-CHM Community Resource Initiative. Acad Emerg Med 2003. [DOI: 10.1197/aemj.10.8.915-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
A major challenge in current research into aging using model organisms is to establish whether different treatments resulting in slowed aging involve common or distinct mechanisms. Such treatments include gene mutation, dietary restriction (DR), and manipulation of reproduction, gonadal signals and temperature. The principal method used to determine whether these treatments act through common mechanisms is to compare the magnitude of the effect on aging of each treatment separately with that when two are applied simultaneously. In this discussion we identify five types of methodological shortcomings that have marred such studies. These are (1) submaximal lifespan-extension by individual treatments, e.g. as a result of the use of hypomorphic rather than null alleles; (2) effects of a single treatment on survival through more than one mechanism, e.g. pleiotropic effects of lifespan mutants; (3) the difficulty of interpreting the magnitude of increases in lifespan in double treatments, and failure to measure and model age-specific mortality rates; (4) the non-specific effects of life extension suppressors; and (5) the possible occurrence of artefactual mutant interactions. When considered in the light of these problems, the conclusions of a number of recent lifespan interaction studies appear questionable. We suggest six rules for avoiding the pitfalls that can beset interaction studies.
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Affiliation(s)
- David Gems
- Department of Biology, University College London, Gower Street, London WC1E 6BT, UK.
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Abstract
Ceramide is known to have major roles in the control of cell proliferation, differentiation, and apoptosis. Recent studies also have shown that ceramide affects steroid production by JEG-3 choriocarcinoma cells, acutely dispersed rat Leydig cells, and ovarian granulosa cells, but the mechanism by which this occurs is unknown. Because ceramide induces apoptosis in many different cell types, we hypothesized that ceramide might affect steroidogenesis and/or induce apoptosis in MA-10 murine Leydig cells. To test this, MA-10 cells were incubated with either the water soluble C2-ceramide, (N-acetyl-sphingosine, 0.01-10 cm); bacterial sphingomyelinase (1-100 mU/ml); or C2-dihydroceramide (N-acetyl-sphinganine, 0.1-10 microM). The data show that N-acetyl-sphingosine significantly increased basal (0.87 +/- 0.2 vs. 0.42 +/- 0.09 ng/mg cell protein, P < 0.01) and human chorionic gonadotropin (hCG) stimulated progesterone (P) synthesis (204 +/- 12 vs. 120 +/- 5 ng/mg cell protein, P < 0.001); as did sphingomyelinase (basal P = 0.83 +/- 0.1 ng/mg cell protein, P < 0.01; hCG stimulated P = 173 +/- 7 ng/mg cell protein, P < 0.001). C2-dihydroceramide also increased basal P synthesis but was less effective than ceramide on a molar basis. Neither sphingomyelinase (100 mU/ml) nor ceramide (10 microM) had any effect on cAMP production or human chorionic gonadotropin binding; and neither induced any signs of apoptosis (FragEL DNA fragmentation assay and electron microscopy). Cells incubated with anti-Fas (300 ng/ml) demonstrated DNA fragmentation, nuclear condensation, and frequent apoptotic bodies, but had no change in P synthesis. These data show that ceramide significantly increases MA-10 Leydig cell P synthesis but does not induce apoptosis. The mechanism by which ceramide increases steroid hormone synthesis remains unknown but does not appear to be linked to the induction of apoptosis in MA-10 cells.
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Affiliation(s)
- C Kwun
- Department of Pediatrics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA
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