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Zhao X, Wang S, Xu J, Wang C, Feng Y, Xue H, Wu M, Chen L, Xu L. Effects of short daylight and mild low temperature on mitochondrial degeneration in the testis of
Cricetulus barabensis. Mol Reprod Dev 2022; 89:413-422. [DOI: 10.1002/mrd.23632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/11/2022] [Accepted: 06/29/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Xiang‐Yu Zhao
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Shuo Wang
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Jin‐Hui Xu
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Chuan‐Li Wang
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Yong‐Zhen Feng
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Hui‐Liang Xue
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Ming Wu
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Lei Chen
- College of Life Sciences Qufu Normal University Qufu Shandong China
| | - Lai‐Xiang Xu
- College of Life Sciences Qufu Normal University Qufu Shandong China
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2
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Microbe-Mineral Interaction and Novel Proteins for Iron Oxide Mineral Reduction in the Hyperthermophilic Crenarchaeon Pyrodictium delaneyi. Appl Environ Microbiol 2021; 87:AEM.02330-20. [PMID: 33419739 PMCID: PMC8105010 DOI: 10.1128/aem.02330-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/17/2020] [Indexed: 11/24/2022] Open
Abstract
Understanding iron reduction in the hyperthermophilic crenarchaeon Pyrodictium delaneyi provides insight into the diversity of mechanisms used for this process and its potential impact in geothermal environments. The ability of P. delaneyi to reduce Fe(III) oxide minerals through direct contact potentially using a novel cytochrome respiratory complex and a membrane-bound molybdopterin respiratory complex sets iron reduction in this organism apart from previously described iron reduction processes. Dissimilatory iron reduction by hyperthermophilic archaea occurs in many geothermal environments and generally relies on microbe-mineral interactions that transform various iron oxide minerals. In this study, the physiology of dissimilatory iron and nitrate reduction was examined in the hyperthermophilic crenarchaeon type strain Pyrodictium delaneyi Su06. Iron barrier experiments showed that P. delaneyi required direct contact with the Fe(III) oxide mineral ferrihydrite for reduction. The separate addition of an exogenous electron shuttle (anthraquinone-2,6-disulfonate), a metal chelator (nitrilotriacetic acid), and 75% spent cell-free supernatant did not stimulate growth with or without the barrier. Protein electrophoresis showed that the c-type cytochrome and general protein compositions of P. delaneyi changed when grown on ferrihydrite relative to nitrate. Differential proteomic analyses using tandem mass tagged protein fragments and mass spectrometry detected 660 proteins and differential production of 127 proteins. Among these, two putative membrane-bound molybdopterin-dependent oxidoreductase complexes increased in relative abundance 60- to 3,000-fold and 50- to 100-fold in cells grown on iron oxide. A putative 8-heme c-type cytochrome was 60-fold more abundant in iron-grown cells and was unique to the Pyrodictiaceae. There was also a >14,700-fold increase in a membrane transport protein in iron-grown cells. For flagellin proteins and a putative nitrate reductase, there were no changes in abundance, but a membrane nitric oxide reductase was more abundant on nitrate. These data help to elucidate the mechanisms by which hyperthermophilic crenarchaea generate energy and transfer electrons across the membrane to iron oxide minerals. IMPORTANCE Understanding iron reduction in the hyperthermophilic crenarchaeon Pyrodictium delaneyi provides insight into the diversity of mechanisms used for this process and its potential impact in geothermal environments. The ability of P. delaneyi to reduce Fe(III) oxide minerals through direct contact potentially using a novel cytochrome respiratory complex and a membrane-bound molybdopterin respiratory complex sets iron reduction in this organism apart from previously described iron reduction processes. A model is presented where obligatory H2 oxidation on the membrane coupled with electron transport and either Fe(III) oxide or nitrate reduction leads to the generation of a proton motive force and energy generation by oxidative phosphorylation. However, P. delaneyi cannot fix CO2 and relies on organic compounds from its environment for biosynthesis.
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3
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Tanaka M, Kanazashi M, Kondo H, Ishihara A, Fujino H. Licorice flavonoid oil supplementation promotes a reduction of visceral fat in exercised rats. J Sports Med Phys Fitness 2020; 61:480-488. [PMID: 33000933 DOI: 10.23736/s0022-4707.20.11260-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND The beneficial effect of exercise combined with licorice flavonoid oil supplementation on visceral fat was investigated. METHODS Male Sprague-Dawley rats were divided into 4 groups: control, exercise (Ex), control with licorice flavonoid oil supplementation (LFO), and exercise with licorice flavonoid oil supplementation (ExLFO) groups. The rats in the Ex and ExLFO groups ran on a treadmill (20-degree incline at 20 m/min for 30 min/day) 5 times a week for 7 weeks, and those in the LFO and ExLFO groups were orally administered with licorice flavonoid oil daily using a feeding needle. RESULTS Exercise or licorice flavonoid oil supplementation resulted in the reduction of the visceral fat mass and adipocyte size, respectively. In addition, exercise combined with licorice flavonoid oil supplementation more effectively decreased both measures. Exercise alone increased the β-hydroxyacyl-CoA dehydrogenase (β-HAD) and citrate synthase (CS) activities in the soleus and plantaris muscles, and licorice flavonoid oil supplementation alone increased the hepatic carnitine palmitoyl transferase-2 (CPT-2) activity. Furthermore, the combination of exercise and licorice flavonoid oil supplementation enhanced the both muscular β-HAD and CS activities, and hepatic CPT-2 activity. CONCLUSIONS These results suggest that exercise combined with licorice flavonoid oil supplementation may be effective to decrease visceral adipose tissue via enhancing skeletomuscular and hepatic fatty acids oxidative capacity.
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Affiliation(s)
- Masayuki Tanaka
- Department of Physical Therapy, Faculty of Health Sciences, Okayama Healthcare Professional University, Okayama, Japan
| | - Miho Kanazashi
- Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Mihara, Japan
| | - Hiroyo Kondo
- Department of Food Sciences and Nutrition, Nagoya Women's University, Nagoya, Japan
| | - Akihiko Ishihara
- Laboratory of Cell Biology and Life Science, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Hidemi Fujino
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Japan -
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4
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Woodman AG, Mah R, Keddie DL, Noble RMN, Holody CD, Panahi S, Gragasin FS, Lemieux H, Bourque SL. Perinatal iron deficiency and a high salt diet cause long-term kidney mitochondrial dysfunction and oxidative stress. Cardiovasc Res 2020; 116:183-192. [PMID: 30715197 DOI: 10.1093/cvr/cvz029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/08/2019] [Accepted: 01/29/2019] [Indexed: 12/15/2022] Open
Abstract
AIMS Perinatal iron deficiency (ID) alters developmental trajectories of offspring, predisposing them to cardiovascular dysfunction in later life. The mechanisms underlying this long-term programming of renal function have not been defined. We hypothesized perinatal ID causes hypertension and alters kidney metabolic function and morphology in a sex-dependent manner in adult offspring. Furthermore, we hypothesized these effects are exacerbated by chronic consumption of a high salt diet. METHODS AND RESULTS Pregnant Sprague Dawley rats were fed either an iron-restricted or replete diet prior to and throughout pregnancy. Adult offspring were fed normal or high salt diets for 6 weeks prior to experimentation at 6 months of age. Blood pressure (BP) was assessed via indwelling catheters in anaesthetized offspring; kidney mitochondrial function was assessed via high-resolution respirometry; reactive oxygen species and nitric oxide were quantified via fluorescence microscopy. Adult males, but not females, exhibited increased systolic BP due to ID (P = 0.01) and high salt intake (P = 0.02). In males, but not in females, medullary mitochondrial content was increased by high salt (P = 0.003), while succinate-dependent respiration was reduced by ID (P < 0.05). The combination of perinatal ID and high salt reduced complex IV activity in the cortex of males (P = 0.01). Perinatal ID increased cytosolic superoxide generation (P < 0.001) concomitant with reduced nitric oxide bioavailability (P < 0.001) in male offspring, while high salt increased mitochondrial superoxide in the medulla (P = 0.04) and cytosolic superoxide within the cortex (P = 0.01). Male offspring exhibited glomerular basement membrane thickening (P < 0.05), increased collagen deposition (P < 0.05), and glomerular hypertrophy (interaction, P = 0.02) due to both perinatal ID and high salt. Female offspring exhibited no alterations in mitochondrial function or morphology due to either high salt or ID. CONCLUSION Perinatal ID causes long-term sex-dependent alterations in renal metabolic function and morphology, potentially contributing to hypertension and increased cardiovascular disease risk.
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Affiliation(s)
- Andrew G Woodman
- Department of Pharmacology, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Richard Mah
- Department of Pharmacology, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Danae L Keddie
- Department of Pharmacology, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Ronan M N Noble
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Canada
| | - Claudia D Holody
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Canada
| | - Sareh Panahi
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Canada
| | - Ferrante S Gragasin
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Canada
| | - Helene Lemieux
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Medicine, University of Alberta, Edmonton, Canada.,Faculty Saint-Jean, University of Alberta, Edmonton, Canada
| | - Stephane L Bourque
- Department of Pharmacology, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Canada.,Department of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Canada
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5
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Mou J, Xu J, Wang Z, Wang C, Yang X, Wang X, Xue H, Wu M, Xu L. Effects of photoperiod on morphology and function in testis and epididymis of Cricetulus barabensis. J Cell Physiol 2020; 236:2109-2125. [PMID: 32743820 DOI: 10.1002/jcp.29998] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 01/03/2023]
Abstract
Photoperiod regulates the seasonal reproductive rhythms of mammals by influencing the development and function of sexual organs; however, the underlying mechanism remains unclear. We examined the morphology and functioning of the main sex organs of striped dwarf hamsters (Cricetulus barabensis) under different photoperiods (short daylight [SD], moderate daylight [MD], and long daylight [LD]) and further investigated the underlying molecular mechanisms. There was an inverse correlation between blood melatonin levels and photoperiod in the order SD > MD > LD. Decreases in body and tissue weights were observed under SD, whereas testis and epididymis weights between MD and LD were comparable. The diameters of the spermatogenic tubules, thickness of the spermatogenic epithelium, and the number of spermatogonia and Sertoli cells decreased under SD, whereas the serum-luteinizing hormone, follicle-stimulating hormone, and fecal testosterone concentrations decreased under LD. In SD, bax/bcl2 protein expression increased in the testes and decreased in the epididymides, whereas LC3II/LC3I remained unchanged in the testes and increased in the epididymides compared with the MD group. In LD, bax/bcl2 and LC3II/LC3I protein expression levels were unchanged in the testes but were decreased in the epididymides. In SD and LD, adenosine triphosphate synthase and citrate synthase protein expression levels were unchanged in the testes but were decreased in the epididymides. Drp1 and Mff protein expression increased in the testes and decreased in the epididymides. Overall, different regulatory mechanisms in the testis and epididymis led to degeneration under SD and maintenance under LD, preferentially protecting mitochondrial function in the testis by regulating mitochondrial fission.
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Affiliation(s)
- Junjie Mou
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Jinhui Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Zhe Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Chuanli Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xueqi Yang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Xingchen Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Huiliang Xue
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Ming Wu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Laixiang Xu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
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6
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Chen Y, Cai GH, Xia B, Wang X, Zhang CC, Xie BC, Shi XC, Liu H, Lu JF, Zhang RX, Zhu MQ, Liu M, Yang SZ, Yang Zhang D, Chu XY, Khan R, Wang YL, Wu JW. Mitochondrial aconitase controls adipogenesis through mediation of cellular ATP production. FASEB J 2020; 34:6688-6702. [PMID: 32212192 DOI: 10.1096/fj.201903224rr] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 11/11/2022]
Abstract
Mitochondrial aconitase (Aco2) catalyzes the conversion of citrate to isocitrate in the TCA cycle, which produces NADH and FADH2, driving synthesis of ATP through OXPHOS. In this study, to explore the relationship between adipogenesis and mitochondrial energy metabolism, we hypothesize that Aco2 may play a key role in the lipid synthesis. Here, we show that overexpression of Aco2 in 3T3-L1 cells significantly increased lipogenesis and adipogenesis, accompanied by elevated mitochondrial biogenesis and ATP production. However, when ATP is depleted by rotenone, an inhibitor of the respiratory chain, the promotive role of Aco2 in adipogenesis is abolished. In contrast to Aco2 overexpression, deficiency of Aco2 markedly reduced lipogenesis and adipogenesis, along with the decreased mitochondrial biogenesis and ATP production. Supplementation of isocitrate efficiently rescued the inhibitory effect of Aco2 deficiency. Similarly, the restorative effect of isocitrate was abolished in the presence of rotenone. Together, these results show that Aco2 sustains normal adipogenesis through mediating ATP production, revealing a potential mechanistic link between TCA cycle enzyme and lipid synthesis. Our work suggest that regulation of adipose tissue mitochondria function may be a potential way for combating abnormal adipogenesis related diseases such as obesity and lipodystrophy.
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Affiliation(s)
- Yan Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Guo He Cai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xin Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Cong Cong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bao Cai Xie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xiao Chen Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Huan Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jun Feng Lu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rui Xin Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Min Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Shi Zhen Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Dan Yang Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xin Yi Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rajwali Khan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yong Liang Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
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7
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Watanabe D, Hatakeyama K, Ikegami R, Eshima H, Yagishita K, Poole DC, Kano Y. Sex differences in mitochondrial Ca 2+ handling in mouse fast-twitch skeletal muscle in vivo. J Appl Physiol (1985) 2020; 128:241-251. [PMID: 31917626 DOI: 10.1152/japplphysiol.00230.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We investigated sex differences in mitochondrial Ca2+ handling properties in mouse fast-twitch skeletal muscle. Changes in cytoplasmic Ca2+ concentration ([Ca2+]cyto) were measured in vivo using tibialis anterior muscles from male and female mice. The muscles were exposed to increasing concentrations of cyclopiazonic acid [CPA; sarcoplasmic reticulum (SR) Ca2+-ATPase inhibitor] (from 10 to 30 to 50 μM at 10 min intervals). Thirty minutes after treatment, [Ca2+]cyto was increased by 31.6 ± 2.0% and 13.5 ± 4.5% of initial [Ca2+]cyto in male and female muscles, respectively, and there was a significant difference between sexes. However, muscle preincubation for 5 min with 10 μM carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (an inhibitor of mitochondria Ca2+ uptake) eradicated this difference between sexes with respect to the CPA-induced [Ca2+]cyto increase. Both intermyofibrillar mitochondrial number and volume, assessed in longitudinal fiber sections, were higher in females compared with males (mitochondria number: 13.1 ± 1.0 in males vs. 19.9 ± 2.3 in females; mitochondrial volume: 0.034 ± 0.004 μm3/μm3 fiber volume in males vs. 0.066 ± 0.008 μm3/μm3 fiber volume in females, both P < 0.05). There were no sex differences in the content of SR Ca2+-ATPase, mitochondrial Ca2+ uniporter, mitofusin (Mfn) 1, or Mfn2. These results suggest that 1) mitochondrial Ca2+ uptake ability is greater in female than male myocytes, and 2) this superior Ca2+ uptake ability of female myocytes is due, partly, to the higher intermyofibrillar mitochondrial content but not to the expression of mitochondrial proteins related to mitochondrial Ca2+ uptake.NEW & NOTEWORTHY This investigation presents evidence that female versus male fast-twitch muscle exhibits a greater mitochondrial calcium ion uptake capability that is partly conferred by the higher intermyofibrillar mitochondrial volume density.
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Affiliation(s)
- Daiki Watanabe
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan.,Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Koji Hatakeyama
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan
| | - Ryo Ikegami
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan
| | - Hiroaki Eshima
- Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Kazuyoshi Yagishita
- Clinical Center for Sports Medicine and Sports Dentistry, Hyperbaric Medical Center/Sports Medicine Clinical Center, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan
| | - David C Poole
- Departments of Anatomy & Physiology and of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan.,Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Tokyo, Japan
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8
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Mitochondrial translation requires folate-dependent tRNA methylation. Nature 2018; 554:128-132. [PMID: 29364879 PMCID: PMC6020024 DOI: 10.1038/nature25460] [Citation(s) in RCA: 177] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 12/14/2017] [Indexed: 12/11/2022]
Abstract
Folates enable the activation and transfer of one-carbon units for biosynthesis of purines, thymidine and methionine1–3. Antifolates are important immunosuppressive4 and anticancer agents5. In proliferating lymphocytes6 and human cancers7,8, folate enzymes localizing to the mitochondria are particularly strongly upregulated. This in part reflects the need for mitochondria to generate one-carbon units and export them to the cytosol for anabolic metabolism2,9. The full range of uses of folate-bound one-carbon units in the mitochondrial compartment itself, however, has not been thoroughly explored. Here we show that loss of catalytic activity of the mitochondrial folate enzyme serine hydroxymethyltransferase 2 (SHMT2), but not other folate enzymes, leads to defective oxidative phosphorylation due to impaired mitochondrial translation. We find that SHMT2, presumably by generating mitochondrial 5,10-methylenetetrahydrofolate, provides methyl donors for producing the taurinomethyluridine base at the wobble position of select mitochondrial tRNAs. Mitochondrial ribosome profiling reveals that SHMT2 knockout cells, due to lack of this modified base, suffer from defective translation with preferential mitochondrial ribosome stalling at certain lysine (AAG) and leucine (UUG) codons. This results in impaired respiratory chain enzyme expression. Stalling at these specific codons also occurs in certain mitochondrial inborn errors of metabolism. Disrupting whole-cell folate metabolism, by folate deficiency or antifolate therapy, also impairs the respiratory chain. In summary, mammalian mitochondria use folate-bound one-carbon units to methylate tRNA, and this modification is required for respiratory chain translation and thus oxidative phosphorylation.
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9
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Woodman AG, Mah R, Keddie D, Noble RMN, Panahi S, Gragasin FS, Lemieux H, Bourque SL. Prenatal iron deficiency causes sex-dependent mitochondrial dysfunction and oxidative stress in fetal rat kidneys and liver. FASEB J 2018; 32:3254-3263. [PMID: 29401611 DOI: 10.1096/fj.201701080r] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Prenatal iron deficiency alters fetal developmental trajectories, which results in persistent changes in organ function. Here, we studied the effects of prenatal iron deficiency on fetal kidney and liver mitochondrial function. Pregnant Sprague-Dawley rats were fed partially or fully iron-restricted diets to induce a state of moderate or severe iron deficiency alongside iron-replete control rats. We assessed mitochondrial function via high-resolution respirometry and reactive oxygen species generation via fluorescence microscopy on gestational d 21. Hemoglobin levels were reduced in dams in the moderate (-31%) and severe groups (-54%) compared with controls, which was accompanied by 55% reductions in fetal hemoglobin levels in both moderate and severe groups versus controls. Male iron-deficient kidneys exhibited globally reduced mitochondrial content and respiration, as well as increased cytosolic superoxide and decreased NO. Female iron-deficient kidneys exhibited complex II down-regulation and increased mitochondrial oxidative stress. Male iron-deficient livers exhibited reduced complex IV respiration and increased cytosolic superoxide, whereas female liver tissues exhibited no alteration in oxidant levels or mitochondrial function. These findings indicate that prenatal iron deficiency causes changes in mitochondrial content and function as well as oxidant status in a sex- and organ-dependent manner, which may be an important mechanism that underlies the programming of cardiovascular disease.-Woodman, A. G., Mah, R., Keddie, D., Noble, R. M. N., Panahi, S., Gragasin, F. S., Lemieux, H., Bourque, S. L. Prenatal iron deficiency causes sex-dependent mitochondrial dysfunction and oxidative stress in fetal rat kidneys and liver.
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Affiliation(s)
- Andrew G Woodman
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Richard Mah
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Danae Keddie
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ronan M N Noble
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Sareh Panahi
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ferrante S Gragasin
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Hélène Lemieux
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Stephane L Bourque
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
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10
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Horii N, Hasegawa N, Fujie S, Uchida M, Miyamoto-Mikami E, Hashimoto T, Tabata I, Iemitsu M. High-intensity intermittent exercise training with chlorella intake accelerates exercise performance and muscle glycolytic and oxidative capacity in rats. Am J Physiol Regul Integr Comp Physiol 2017; 312:R520-R528. [DOI: 10.1152/ajpregu.00383.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 01/07/2023]
Abstract
The purpose of this study was to investigate the effect of chronic chlorella intake alone or in combination with high-intensity intermittent exercise (HIIE) training on exercise performance and muscle glycolytic and oxidative metabolism in rats. Forty male Sprague-Dawley rats were randomly assigned to the four groups: sedentary control, chlorella intake (0.5% chlorella powder in normal feed), HIIE training, and combination of HIIE training and chlorella intake for 6 wk ( n = 10 each group). HIIE training comprised 14 repeats of a 20-s swimming session with a 10-s pause between sessions, while bearing a weight equivalent to 16% of body weight, 4 days/week. Exercise performance was tested after the interventions by measuring the maximal number of HIIE sessions that could be completed. Chlorella intake and HIIE training significantly increased the maximal number of HIIE sessions and enhanced the expression of monocarboxylate transporter (MCT)1, MCT4, and peroxisome proliferator-activated receptor γ coactivator-1α concomitantly with the activities of lactate dehydrogenase (LDH), phosphofructokinase, citrate synthase (CS), and cytochrome- c oxidase (COX) in the red region of the gastrocnemius muscle. Furthermore, the combination further augmented the increased exercise performance and the enhanced expressions and activities. By contrast, in the white region of the muscle, MCT1 expression and LDH, CS, and COX activities did not change. These results showed that compared with only chlorella intake and only HIIE training, chlorella intake combined with HIIE training has a more pronounced effect on exercise performance and muscle glycolytic and oxidative metabolism, in particular, lactate metabolism.
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Affiliation(s)
- Naoki Horii
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
| | - Natsuki Hasegawa
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Shumpei Fujie
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Masataka Uchida
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
| | - Eri Miyamoto-Mikami
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
| | - Takeshi Hashimoto
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
| | - Izumi Tabata
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
| | - Motoyuki Iemitsu
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; and
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11
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Open-Loop Control of Oxidative Phosphorylation in Skeletal and Cardiac Muscle Mitochondria by Ca(2.). Biophys J 2016; 110:954-61. [PMID: 26910432 DOI: 10.1016/j.bpj.2015.12.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 09/29/2015] [Accepted: 12/14/2015] [Indexed: 01/16/2023] Open
Abstract
In cardiac muscle, mitochondrial ATP synthesis is driven by demand for ATP through feedback from the products of ATP hydrolysis. However, in skeletal muscle at higher workloads there is an apparent contribution of open-loop stimulation of ATP synthesis. Open-loop control is defined as modulation of flux through a biochemical pathway by a moiety, which is not a reactant or a product of the biochemical reactions in the pathway. The role of calcium, which is known to stimulate the activity of mitochondrial dehydrogenases, as an open-loop controller, was investigated in isolated cardiac and skeletal muscle mitochondria. The kinetics of NADH synthesis and respiration, feedback from ATP hydrolysis products, and stimulation by calcium were characterized in isolated mitochondria to test the hypothesis that calcium has a stimulatory role in skeletal muscle mitochondria not apparent in cardiac mitochondria. A range of respiratory states were obtained in cardiac and skeletal muscle mitochondria utilizing physiologically relevant concentrations of pyruvate and malate, and flux of respiration, NAD(P)H fluorescence, and rhodamine 123 fluorescence were measured over a range of extra mitochondrial calcium concentrations. We found that under these conditions calcium stimulates NADH synthesis in skeletal muscle mitochondria but not in cardiac mitochondria.
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12
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Yang H, Wu JW, Wang SP, Severi I, Sartini L, Frizzell N, Cinti S, Yang G, Mitchell GA. Adipose-Specific Deficiency of Fumarate Hydratase in Mice Protects Against Obesity, Hepatic Steatosis, and Insulin Resistance. Diabetes 2016; 65:3396-3409. [PMID: 27554470 PMCID: PMC5860441 DOI: 10.2337/db16-0136] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 08/16/2016] [Indexed: 01/08/2023]
Abstract
Obesity and type 2 diabetes are associated with impaired mitochondrial function in adipose tissue. To study the effects of primary deficiency of mitochondrial energy metabolism in fat, we generated mice with adipose-specific deficiency of fumarate hydratase (FH), an integral Krebs cycle enzyme (AFHKO mice). AFHKO mice have severe ultrastructural abnormalities of mitochondria, ATP depletion in white adipose tissue (WAT) and brown adipose tissue, low WAT mass with small adipocytes, and impaired thermogenesis with large unilocular brown adipocytes. AFHKO mice are strongly protected against obesity, insulin resistance, and fatty liver despite aging and high-fat feeding. AFHKO white adipocytes showed normal lipolysis but low triglyceride synthesis. ATP depletion in normal white adipocytes by mitochondrial toxins also decreased triglyceride synthesis, proportionally to ATP depletion, suggesting that reduced triglyceride synthesis may result nonspecifically from adipocyte energy deficiency. At thermoneutrality, protection from insulin resistance and hepatic steatosis was diminished. Taken together, the results show that under the cold stress of regular animal room conditions, adipocyte-specific FH deficiency in mice causes mitochondrial energy depletion in adipose tissues and protects from obesity, hepatic steatosis, and insulin resistance, suggesting that in cold-stressed animals, mitochondrial function in adipose tissue is a determinant of fat mass and insulin sensitivity.
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Affiliation(s)
- Hao Yang
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Jiang W Wu
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Shu P Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Ilenia Severi
- Department of Experimental and Clinical Medicine, Center of Obesity, United Hospitals, University of Ancona (Università Politecnica Delle Marche), Ancona, Italy
| | - Loris Sartini
- Department of Experimental and Clinical Medicine, Center of Obesity, United Hospitals, University of Ancona (Università Politecnica Delle Marche), Ancona, Italy
| | - Norma Frizzell
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC
| | - Saverio Cinti
- Department of Experimental and Clinical Medicine, Center of Obesity, United Hospitals, University of Ancona (Università Politecnica Delle Marche), Ancona, Italy
| | - Gongshe Yang
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Grant A Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montreal, Quebec, Canada
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13
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Dirks ML, Wall BT, van de Valk B, Holloway TM, Holloway GP, Chabowski A, Goossens GH, van Loon LJC. One Week of Bed Rest Leads to Substantial Muscle Atrophy and Induces Whole-Body Insulin Resistance in the Absence of Skeletal Muscle Lipid Accumulation. Diabetes 2016; 65:2862-75. [PMID: 27358494 DOI: 10.2337/db15-1661] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 06/23/2016] [Indexed: 11/13/2022]
Abstract
Short (<10 days) periods of muscle disuse, often necessary for recovery from illness or injury, lead to various negative health consequences. The current study investigated mechanisms underlying disuse-induced insulin resistance, taking into account muscle atrophy. Ten healthy, young males (age: 23 ± 1 years; BMI: 23.0 ± 0.9 kg · m(-2)) were subjected to 1 week of strict bed rest. Prior to and after bed rest, lean body mass (dual-energy X-ray absorptiometry) and quadriceps cross-sectional area (CSA; computed tomography) were assessed, and peak oxygen uptake (VO2peak) and leg strength were determined. Whole-body insulin sensitivity was measured using a hyperinsulinemic-euglycemic clamp. Additionally, muscle biopsies were collected to assess muscle lipid (fraction) content and various markers of mitochondrial and vascular content. Bed rest resulted in 1.4 ± 0.2 kg lean tissue loss and a 3.2 ± 0.9% decline in quadriceps CSA (both P < 0.01). VO2peak and one-repetition maximum declined by 6.4 ± 2.3 (P < 0.05) and 6.9 ± 1.4% (P < 0.01), respectively. Bed rest induced a 29 ± 5% decrease in whole-body insulin sensitivity (P < 0.01). This was accompanied by a decline in muscle oxidative capacity, without alterations in skeletal muscle lipid content or saturation level, markers of oxidative stress, or capillary density. In conclusion, 1 week of bed rest substantially reduces skeletal muscle mass and lowers whole-body insulin sensitivity, without affecting mechanisms implicated in high-fat diet-induced insulin resistance.
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Affiliation(s)
- Marlou L Dirks
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastrict, the Netherlands
| | - Benjamin T Wall
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastrict, the Netherlands
| | - Bas van de Valk
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastrict, the Netherlands
| | - Tanya M Holloway
- Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Graham P Holloway
- Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Adrian Chabowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
| | - Gijs H Goossens
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastrict, the Netherlands
| | - Luc J C van Loon
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastrict, the Netherlands
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14
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Prior SJ, Goldberg AP, Ortmeyer HK, Chin ER, Chen D, Blumenthal JB, Ryan AS. Increased Skeletal Muscle Capillarization Independently Enhances Insulin Sensitivity in Older Adults After Exercise Training and Detraining. Diabetes 2015; 64:3386-95. [PMID: 26068543 PMCID: PMC4587640 DOI: 10.2337/db14-1771] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 05/23/2015] [Indexed: 01/04/2023]
Abstract
Intramuscular signaling and glucose transport mechanisms contribute to improvements in insulin sensitivity after aerobic exercise training. This study tested the hypothesis that increases in skeletal muscle capillary density (CD) also contribute to exercise-induced improvements in whole-body insulin sensitivity (insulin-stimulated glucose uptake per unit plasma insulin [M/I]) independent of other mechanisms. The study design included a 6-month aerobic exercise training period followed by a 2-week detraining period to eliminate short-term effects of exercise on intramuscular signaling and glucose transport. Before and after exercise training and detraining, 12 previously sedentary older (65 ± 3 years) men and women underwent research tests, including hyperinsulinemic-euglycemic clamps and vastus lateralis biopsies. Exercise training increased Vo2max (2.2 ± 0.2 vs. 2.5 ± 0.2 L/min), CD (313 ± 13 vs. 349 ± 18 capillaries/mm(2)), and M/I (0.041 ± 0.005 vs. 0.051 ± 0.007 μmol/kg fat-free mass/min) (P < 0.05 for all). Exercise training also increased the insulin activation of glycogen synthase by 60%, GLUT4 expression by 16%, and 5' AMPK-α1 expression by 21%, but these reverted to baseline levels after detraining. Conversely, CD and M/I remained 15% and 18% higher after detraining, respectively (P < 0.05), and the changes in M/I (detraining minus baseline) correlated directly with changes in CD in regression analysis (partial r = 0.70; P = 0.02). These results suggest that an increase in CD is one mechanism contributing to sustained improvements in glucose metabolism after aerobic exercise training.
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Affiliation(s)
- Steven J Prior
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Andrew P Goldberg
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Heidi K Ortmeyer
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Eva R Chin
- Department of Kinesiology, University of Maryland School of Public Health, College Park, MD
| | - Dapeng Chen
- Department of Kinesiology, University of Maryland School of Public Health, College Park, MD
| | - Jacob B Blumenthal
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Alice S Ryan
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
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15
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Marco-Urrea E, Paul S, Khodaverdi V, Seifert J, von Bergen M, Kretzschmar U, Adrian L. Identification and characterization of a re-citrate synthase in Dehalococcoides strain CBDB1. J Bacteriol 2011; 193:5171-8. [PMID: 21784924 PMCID: PMC3187404 DOI: 10.1128/jb.05120-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 07/17/2011] [Indexed: 01/12/2023] Open
Abstract
The genome annotations of all sequenced Dehalococcoides strains lack a citrate synthase, although physiological experiments have indicated that such an activity should be encoded. We here report that a Re face-specific citrate synthase is synthesized by Dehalococcoides strain CBDB1 and that this function is encoded by the gene cbdbA1708 (NCBI accession number CAI83711), previously annotated as encoding homocitrate synthase. Gene cbdbA1708 was heterologously expressed in Escherichia coli, and the recombinant enzyme was purified. The enzyme catalyzed the condensation of oxaloacetate and acetyl coenzyme A (acetyl-CoA) to citrate. The protein did not have homocitrate synthase activity and was inhibited by citrate, and Mn2+ was needed for full activity. The stereospecificity of the heterologously expressed citrate synthase was determined by electrospray ionization liquid chromatography-mass spectrometry (ESI LC/MS). Citrate was synthesized from [2-(13)C]acetyl-CoA and oxaloacetate by the Dehalococcoides recombinant citrate synthase and then converted to acetate and malate by commercial citrate lyase plus malate dehydrogenase. The formation of unlabeled acetate and 13C-labeled malate proved the Re face-specific activity of the enzyme. Shotgun proteome analyses of cell extracts of strain CBDB1 demonstrated that cbdbA1708 is expressed in strain CBDB1.
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Affiliation(s)
- Ernest Marco-Urrea
- Helmholtz Centre for Environmental Research—UFZ, Department of Isotope Biogeochemistry, Leipzig, Germany
- Department of Chemical Engineering, Autonomous University of Barcelona, Bellaterra 08193, Spain
| | - Steffanie Paul
- Technische Universität Berlin, FG Angewandte Biochemie, Berlin, Germany
| | - Viola Khodaverdi
- Technische Universität Berlin, FG Angewandte Biochemie, Berlin, Germany
| | - Jana Seifert
- Helmholtz Centre for Environmental Research—UFZ, Department of Proteomics, Leipzig, Germany
| | - Martin von Bergen
- Helmholtz Centre for Environmental Research—UFZ, Department of Proteomics, Leipzig, Germany
| | - Utta Kretzschmar
- Technische Universität Berlin, FG Angewandte Biochemie, Berlin, Germany
| | - Lorenz Adrian
- Helmholtz Centre for Environmental Research—UFZ, Department of Isotope Biogeochemistry, Leipzig, Germany
- Technische Universität Berlin, FG Angewandte Biochemie, Berlin, Germany
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16
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Hu Y, Holden JF. Citric acid cycle in the hyperthermophilic archaeon Pyrobaculum islandicum grown autotrophically, heterotrophically, and mixotrophically with acetate. J Bacteriol 2006; 188:4350-5. [PMID: 16740941 PMCID: PMC1482950 DOI: 10.1128/jb.00138-06] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hyperthermophilic archaeon Pyrobaculum islandicum uses the citric acid cycle in the oxidative and reductive directions for heterotrophic and autotrophic growth, respectively, but the control of carbon flow is poorly understood. P. islandicum was grown at 95 degrees C autotrophically, heterotrophically, and mixotrophically with acetate, H2, and small amounts of yeast extract and with thiosulfate as the terminal electron acceptor. The autotrophic growth rates and maximum concentrations of cells were significantly lower than those in other media. The growth rates on H2 and 0.001% yeast extract with and without 0.05% acetate were the same, but the maximum concentration of cells was fourfold higher with acetate. There was no growth with acetate if 0.001% yeast extract was not present, and addition of H2 to acetate-containing medium greatly increased the growth rates and maximum concentrations of cells. P. islandicum cultures assimilated 14C-labeled acetate in the presence of H2 and yeast extract with an efficiency of 55%. The activities of 11 of 19 enzymes involved in the central metabolism of P. islandicum were regulated under the three different growth conditions. Pyruvate synthase and acetate:coenzyme A (CoA) ligase (ADP-forming) activities were detected only in heterotrophically grown cultures. Citrate synthase activity decreased in autotrophic and acetate-containing cultures compared to the activity in heterotrophic cultures. Acetylated citrate lyase, acetate:CoA ligase (AMP forming), and phosphoenolpyruvate carboxylase activities increased in autotrophic and acetate-containing cultures. Citrate lyase activity was higher than ATP citrate synthase activity in autotrophic cultures. These data suggest that citrate lyase and AMP-forming acetate:CoA ligase, but not ATP citrate synthase, work opposite citrate synthase to control the direction of carbon flow in the citric acid cycle.
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Affiliation(s)
- Yajing Hu
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
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17
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Kumar S, Nussinov R. Different roles of electrostatics in heat and in cold: adaptation by citrate synthase. Chembiochem 2004; 5:280-90. [PMID: 14997520 DOI: 10.1002/cbic.200300627] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electrostatics plays a major role in heat adaptation by thermophilic proteins. Here we ask whether electrostatics similarly contributes to cold adaptation in psychrophilic proteins. We compare the sequences and structures of citrate synthases from the psychrophile Arthobacter Ds2-3R, from chicken, and from the hyperthermophile Pyrococcus furiosus. The three enzymes share similar packing, burial of nonpolar surface area, and main-chain hydrogen bonding. However, both psychrophilic and hyperthermophilic citrate synthases contain more charged residues, salt bridges, and salt-bridge networks than the mesophile. The electrostatic free-energy contributions toward protein stability by individual charged residues show greater variabilities in the psychrophilic citrate synthase than in the hyperthermophilic enzyme. The charged residues in the active-site regions of the psychrophile are more destabilizing than those in the active-site regions of the hyperthermophile. In the hyperthermophilic enzyme, salt bridges and their networks largely cluster in the active-site regions and at the dimer interface. In contrast, in the psychrophile, they are more dispersed throughout the structure. On average, salt bridges and their networks provide greater electrostatic stabilization to the thermophilic citrate synthase at 100 degrees C than to the psychrophilic enzyme at 0 degrees C. Electrostatics appears to play an important role in both heat and cold adaptation of citrate synthase. However, remarkably, the role may be different in the two types of enzyme: In the hyperthermophile, it may contribute to the integrity of both the protein dimer and the active site by possibly countering conformational disorder at high temperatures. On the other hand, in the psychrophile at low temperatures, electrostatics may contribute to enhance protein solvation and to ensure active-site flexibility.
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Affiliation(s)
- Sandeep Kumar
- Basic Research Program, SAIC-Frederick, Inc., Laboratory of Experimental and Computational Biology, NCI-Frederick, Building 469, Room 151, Frederick, MD 21702, USA
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18
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Bell GS, Russell RJM, Connaris H, Hough DW, Danson MJ, Taylor GL. Stepwise adaptations of citrate synthase to survival at life's extremes. From psychrophile to hyperthermophile. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:6250-60. [PMID: 12473121 DOI: 10.1046/j.1432-1033.2002.03344.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The crystal structure of citrate synthase from the thermophilic Archaeon Sulfolobus solfataricus (optimum growth temperature = 85 degrees C) has been determined, extending the number of crystal structures of citrate synthase from different organisms to a total of five that span the temperature range over which life exists (from psychrophile to hyperthermophile). Detailed structural analysis has revealed possible molecular mechanisms that determine the different stabilities of the five proteins. The key to these mechanisms is the precise structural location of the additional interactions. As one ascends the temperature ladder, the subunit interface of this dimeric enzyme and loop regions are reinforced by complex electrostatic interactions, and there is a reduced exposure of hydrophobic surface. These observations reveal a progressive pattern of stabilization through multiple additional interactions at solvent exposed, loop and interfacial regions.
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Affiliation(s)
- Graeme S Bell
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, UK
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