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Collodel G, Moretti E, Noto D, Corsaro R, Signorini C. Oxidation of Polyunsaturated Fatty Acids as a Promising Area of Research in Infertility. Antioxidants (Basel) 2022; 11:antiox11051002. [PMID: 35624866 PMCID: PMC9137497 DOI: 10.3390/antiox11051002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 02/01/2023] Open
Abstract
In this review, the role of fatty acids (FA) in human pathological conditions, infertility in particular, was considered. FA and FA-derived metabolites modulate cell membrane composition, membrane lipid microdomains and cell signaling. Moreover, such molecules are involved in cell death, immunological responses and inflammatory processes. Human health and several pathological conditions are specifically associated with both dietary and cell membrane lipid profiles. The role of FA metabolism in human sperm and spermatogenesis has recently been investigated. Cumulative findings indicate F2 isoprostanes (oxygenated products from arachidonic acid metabolism) and resolvins (lipid mediators of resolution of inflammation) as promising biomarkers for the evaluation of semen and follicular fluid quality. Advanced knowledge in this field could lead to new scenarios in the treatment of infertility.
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De León-Ramírez YM, Lara-García M, Pacheco P, Lara-García O, Martínez-Gómez M, Cuevas-Romero E, Rodríguez-Antolín J, Nicolás-Toledo L. Histomorphological testicular changes and decrease in the sperm count in pubertal rats induced by a high-sugar diet. Ann Anat 2021; 235:151678. [PMID: 33515690 DOI: 10.1016/j.aanat.2021.151678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/01/2020] [Accepted: 12/29/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND During childhood and adolescence, excessive food consumption stimulates adipose tissue expansion promoting overweight in humans, and mice. A high-sucrose diet is related to obesity and metabolic syndrome. Infertility is commonly related to these pathologies. We aim to evaluate possible histomorphological testicular changes induced by a high-sucrose diet on sperm count during the post-weaning period. METHODS Wistar male rats aged 21 days, weaned, were randomly assigned into two groups: control (fed and hydrated normally) and sugar group (fed normally but hydrated with a solution containing 30% of diluted sucrose during 30 days). At the pubertal age of 51 days, animals were killed and blood samples were taken to measure testosterone and leptin. Testicles were collected and gonadal adipose tissue and semen samples from the epididymis were excised. Testicle samples were used for morphological description using H&E staining, as well as to quantify the triacylglycerol content and the lactate dehydrogenase (LDH) expression. Semen samples were used to assess motility, viability, and sperm count. RESULTS The sugar group presented an increase in the testicular weight, but a reduction in the cross-sectional area of seminiferous tubules. Moreover, disorganization of Sertoli cells and spermatogonia, an increase in the LDH expression within the entire seminiferous tubule, and a reduced sperm count and spermatozoid motility were found. These alterations were accompanied by high serum levels of testosterone and leptin. CONCLUSIONS Our results indicate strong damage of testis by sugar consumption during early life that may lead to the onset of infertility in adulthood.
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Affiliation(s)
| | | | - Pablo Pacheco
- Instituto de Neuroetología, Universidad Veracruzana, Veracruz, México; Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Omar Lara-García
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Margarita Martínez-Gómez
- Instituto de Neuroetología, Universidad Veracruzana, Veracruz, México; Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Estela Cuevas-Romero
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Jorge Rodríguez-Antolín
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Leticia Nicolás-Toledo
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.
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Batista-Silva H, Rodrigues K, Sousa de Moura KR, Van Der Kraak G, Delalande-Lecapitaine C, Mena Barreto Silva FR. Role of bisphenol A on calcium influx and its potential toxicity on the testis of Danio rerio. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110876. [PMID: 32563953 DOI: 10.1016/j.ecoenv.2020.110876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
This study investigated the acute in vitro effect of low-concentration bisphenol A (BPA) on calcium (45Ca2+) influx in zebrafish (Danio rerio) testis and examined whether intracellular Ca2+ was involved in the effects of BPA on testicular toxicity. In vitro studies on 45Ca2+ influx were performed in the testes after incubation with BPA for 30 min. Inhibitors were added 15 min before the addition of 45Ca2+ and BPA to testes to study the mechanism of action of BPA. The involvement of intracellular calcium from stores on lactate dehydrogenase (LDH) release and on triacylglycerol (TAG) content were carried out after in vitro incubation of testes with BPA for 1 h. Furthermore, gamma-glutamyl transpeptidase (GGT) and aspartate aminotransferase (AST) activities were analyzed in the liver at 1 h after in vitro BPA incubation of D. rerio. Our data show that the acute in vitro treatment of D. rerio testes with BPA at very low concentration activates plasma membrane ionic channels, such as voltage-dependent calcium channels and calcium-dependent chloride channels, and protein kinase C (PKC), which stimulates Ca2+ influx. In addition, BPA increased cytosolic Ca2+ by activating inositol triphosphate receptor (IP3R) and inhibiting sarco/endoplasmic reticulum calcium ATPase (SERCA) at the endoplasmic reticulum, contributing to intracellular Ca2+ overload. The protein kinases, PKC, MEK 1/2 and PI3K, are involved in the mechanism of action of BPA, which may indicate a crosstalk between the non-genomic initiation effects mediated by PLC/PKC/IP3R signaling and genomic responses of BPA mediated by the estrogen receptor (ESR). In vitro exposure to a higher concentration of BPA caused cell damage and plasma membrane injury with increased LDH release and TAG content; both effects were dependent on intracellular Ca2+ and mediated by IP3R. Furthermore, BPA potentially induced liver damage, as demonstrated by increased GGT activity. In conclusion, in vitro effect of BPA in a low concentration triggers cytosolic Ca2+ overload and activates downstream protein kinases pointing to a crosstalk between its non-genomic and genomic effects of BPA mediated by ESR. Moreover, in vitro exposure to a higher concentration of BPA caused intracellular Ca2+-dependent testicular cell damage and plasma membrane injury. This acute toxicity was reinforced by increased testicular LDH release and GGT activity in the liver.
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Affiliation(s)
- Hemily Batista-Silva
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil; Département Biologie et Sciences de La Terre, Université de Caen Normandie, Caen, Normandie, France
| | - Keyla Rodrigues
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil
| | | | - Glen Van Der Kraak
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | | | - Fátima Regina Mena Barreto Silva
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, CEP: 88040-900, Florianópolis, Santa Catarina, Brazil.
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Jin M, Monroig Ó, Navarro JC, Tocher DR, Zhou QC. Molecular and functional characterisation of two elovl4 elongases involved in the biosynthesis of very long-chain (> C 24 ) polyunsaturated fatty acids in black seabream Acanthopagrus schlegelii. Comp Biochem Physiol B Biochem Mol Biol 2017; 212:41-50. [DOI: 10.1016/j.cbpb.2017.06.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 01/08/2023]
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Long-chain polyunsaturated fatty acid biosynthesis in chordates: Insights into the evolution of Fads and Elovl gene repertoire. Prog Lipid Res 2016; 62:25-40. [DOI: 10.1016/j.plipres.2016.01.001] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/28/2015] [Accepted: 01/01/2016] [Indexed: 01/01/2023]
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Vallés AS, Aveldaño MI, Furland NE. Altered lipid homeostasis in Sertoli cells stressed by mild hyperthermia. PLoS One 2014; 9:e91127. [PMID: 24690895 PMCID: PMC3972175 DOI: 10.1371/journal.pone.0091127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/10/2014] [Indexed: 11/20/2022] Open
Abstract
Spermatogenesis is known to be vulnerable to temperature. Exposures of rat testis to moderate hyperthermia result in loss of germ cells with survival of Sertoli cells (SC). Because SC provide structural and metabolic support to germ cells, our aim was to test the hypothesis that these exposures affect SC functions, thus contributing to germ cell damage. In vivo, regularly repeated exposures (one of 15 min per day, once a day during 5 days) of rat testes to 43 °C led to accumulation of neutral lipids. This SC-specific lipid function took 1-2 weeks after the last of these exposures to be maximal. In cultured SC, similar daily exposures for 15 min to 43 °C resulted in significant increase in triacylglycerol levels and accumulation of lipid droplets. After incubations with [3H]arachidonate, the labeling of cardiolipin decreased more than that of other lipid classes. Another specifically mitochondrial lipid metabolic function, fatty acid oxidation, also declined. These lipid changes suggested that temperature affects SC mitochondrial physiology, which was confirmed by significantly increased degrees of membrane depolarization and ROS production. This concurred with reduced expression of two SC-specific proteins, transferrin, and Wilms' Tumor 1 protein, markers of SC secretion and differentiation functions, respectively, and with an intense SC cytoskeletal perturbation, evident by loss of microtubule network (α-tubulin) and microfilament (f-actin) organization. Albeit temporary and potentially reversible, hyperthermia-induced SC structural and metabolic alterations may be long-lasting and/or extensive enough to respond for the decreased survival of the germ cells they normally foster.
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Affiliation(s)
- Ana S. Vallés
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Marta I. Aveldaño
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Natalia E. Furland
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
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Kheradmand A, Dezfoulian O, Alirezaei M, Hadian B. Ghrelin is a suppressor of testicular damage following experimentally induced cryptorchidism in the rat. J Pediatr Surg 2014; 49:593-8. [PMID: 24726120 DOI: 10.1016/j.jpedsurg.2013.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 10/03/2013] [Accepted: 10/04/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Cryptorchidism is associated with increased level of reactive oxygen species and lipid peroxidation. This study was undertaken to examine the possible ghrelin ability in attenuation of testicular damage in response to elevated temperature. METHODS Thirty male rats were subdivided into sham-operated, cryptorchidism-saline and cryptorchidism-ghrelin group. Bilateral cryptorchidism was induced in groups 2 and 3, surgically. The animals in group 3 were given ghrelin for 7 days and all testes were taken for biochemical and photomicrograph analysis. RESULTS Glutathione peroxidase activity and glutathione content significantly promoted on day 7 in the cryptorchid rats treated by ghrelin. Catalase activity was higher in the ghrelin-exposed animals than the cryptorchidism-saline group on both experimental days. Although superoxide dismutase activity was elevated by ghrelin treatment on both days, it did not differ significantly. By contrast, significant reduction was observed in thiobarbituric acid reactive substances concentrations following ghrelin administration on day 7. Moreover, ghrelin could improve histopathological scores of the testes, and diminished formation of giant cells and tubular vacuolization. CONCLUSIONS These findings indicate for the first time the novel evidence of ghrelin antioxidant properties in attenuation of rat testicular injury following experimentally induced cryptorchidism.
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Affiliation(s)
- Arash Kheradmand
- Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad, Iran.
| | - Omid Dezfoulian
- Department of Pathobiology, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad, Iran
| | - Masoud Alirezaei
- Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad, Iran
| | - Babak Hadian
- Department of Nephrology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorram Abad, Iran
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Zanetti SR, Aveldaño MI. Long-term biopermanence of ceramides, cholesteryl esters, and ether-linked triglycerides with very-long-chain PUFA in the cadmium-damaged testis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:151-61. [DOI: 10.1016/j.bbalip.2013.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/18/2013] [Accepted: 09/23/2013] [Indexed: 01/19/2023]
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Norambuena F, Estévez A, Mañanós E, Bell JG, Carazo I, Duncan N. Effects of graded levels of arachidonic acid on the reproductive physiology of Senegalese sole (Solea senegalensis): Fatty acid composition, prostaglandins and steroid levels in the blood of broodstock bred in captivity. Gen Comp Endocrinol 2013; 191:92-101. [PMID: 23792033 DOI: 10.1016/j.ygcen.2013.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 05/27/2013] [Accepted: 06/01/2013] [Indexed: 11/24/2022]
Abstract
Previous studies on Senegalese sole (Solea senegalensis) indicated that cultured broodstock (first generation, G1) have lower tissue levels of arachidonic acid (20:4n-6, ARA) than wild counterparts. ARA is metabolized to form prostaglandins (PGs) that are involved in steroid production and follicle maturation in fish. In the present study the effects of different dietary levels of ARA on blood lipid and fatty acid composition, prostaglandin (PGF2α, PGF3α, PGE2 and PGE3) levels and plasmatic steroid levels (11-ketotestosterone, 11-KT, testosterone, T and estradiol, E2) in G1 Senegalese sole were studied. For this purpose, 12 groups of ten fish (1:1 male and female), were fed six diets (each diets was fed to two groups) with different dietary ARA levels over nine months (diets A=0.7, B=1.6, C=2.3, D=3.2, E=5.0, F=6.0% ARA). ARA and CHOL levels in blood showed a significant increase in an ARA dose related manner (P<0.05) whereas EPA and EPA/ARA ratio were reduced. In males, steroid (11-KT and T) levels increased significantly with increasing dietary ARA in a dose dependent manner, whereas in females E2 did not show any change related to dietary ARA content. Plasma concentration of 3-series PGs (i.e., PGE3 and PGF3α) were reduced in parallel to increased ARA levels in blood (P<0.05) and levels of PGs 3-series were always higher than 2-series PGs (PGE2 and PGF2α). In conclusion there is an effect of dietary ARA on steroid production of Senegalese sole males, which might have important consequences in the reproduction of cultured fish.
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Affiliation(s)
- Fernando Norambuena
- IRTA-Sant Carles de la Rápita, Ctra. Poble Nou Km 6, 43540-Sant Carles de la Ràpita, Tarragona, Spain.
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Transient scrotal hyperthermia induces lipid droplet accumulation and reveals a different ADFP expression pattern between the testes and liver in mice. PLoS One 2012; 7:e45694. [PMID: 23056214 PMCID: PMC3464254 DOI: 10.1371/journal.pone.0045694] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 08/24/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In most mammals, the testes provide a stable environment for spermatogenesis, which depends on a lower temperature than the core body temperature. It has been reported that mild testicular heating safely and reversibly suppresses spermatogenesis, and is under consideration for its potential application as a male contraceptive. Previously, we focused on the molecular mechanism of germ cell apoptosis and anti-apoptotic factors induced by heat treatment in humans and mice. However, the recovery process remains under investigation. RESULTS In this study, we found that lipid droplets in mouse testes are dramatically increased after a brief period of scrotal hyperthermia, and gradually dissipate following temperature normalization. Analysis of the human testis proteome revealed nine proteins associated with lipid droplets. Two of them, ADFP (also known as ADRP and PLIN2) and TIP47 (also known as PLIN3) may participate in acute lipid droplet formation in mammalian testes. We show that Adfp expression is upregulated after scrotal heat treatment in mice. Surprisingly, we find Adfp lacking its 5'-UTR is observed in Adfp(Δ1/Δ1) mouse testes, but is not detectable in liver. CONCLUSIONS These results reveal testis Adfp transcriptional regulation is tissue-specific, and is associated with lipid droplet accumulation induced by heat. The results also indicate that the testes could retain functional proteins through testes-specific transcriptional regulation.
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Koeberle A, Shindou H, Harayama T, Yuki K, Shimizu T. Polyunsaturated fatty acids are incorporated into maturating male mouse germ cells by lysophosphatidic acid acyltransferase 3. FASEB J 2011; 26:169-80. [DOI: 10.1096/fj.11-184879] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andreas Koeberle
- Department of Biochemistry and Molecular BiologyFaculty of Medicine, University of Tokyo Tokyo Japan
| | - Hideo Shindou
- Department of Biochemistry and Molecular BiologyFaculty of Medicine, University of Tokyo Tokyo Japan
| | - Takeshi Harayama
- Department of Biochemistry and Molecular BiologyFaculty of Medicine, University of Tokyo Tokyo Japan
| | - Koichi Yuki
- Department of Biochemistry and Molecular BiologyFaculty of Medicine, University of Tokyo Tokyo Japan
| | - Takao Shimizu
- Department of Biochemistry and Molecular BiologyFaculty of Medicine, University of Tokyo Tokyo Japan
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Carmona-Antoñanzas G, Monroig Ó, Dick JR, Davie A, Tocher DR. Biosynthesis of very long-chain fatty acids (C>24) in Atlantic salmon: Cloning, functional characterisation, and tissue distribution of an Elovl4 elongase. Comp Biochem Physiol B Biochem Mol Biol 2011; 159:122-9. [DOI: 10.1016/j.cbpb.2011.02.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 02/28/2011] [Accepted: 02/28/2011] [Indexed: 02/05/2023]
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Abstract
The present study investigated whether fatty acid compositions of testes are affected by the obese condition and dietary n-3 long-chain fatty acid (LCFA) intake. Male lean and obese Zucker rats were fed a 15 % (w/w, total diet) fat diet containing either 0 or 5·0 % (w/w, total fatty acids) n-3 LCFA for 8 weeks. Reproductive organ weights, sperm morphology and fatty acid composition of phosphatidylcholine (PC), and phosphatidylethanolamine (PE) of testes were analysed. The obese rats had significantly (P < 0·0001) smaller epididymides and seminal vesicles, larger prostates and abundant underdeveloped testes compared with lean rats. Diet treatment did not affect the sex organ weights. The effect of genotype on fatty acid composition was minor in PC and PE except for DHA (22 : 6n-3). The n-3 LCFA diet significantly (P < 0·0001) elevated 22 : 6n-3 and reduced arachidonic acid (20 : 4n-6) and DPA (22 : 5n-6) in testicular PC and PE of lean and obese rats compared with the control diet. The acylation of dietary n-3 LCFA into 22 : 6n-3 was 2-fold higher in obese rat testes than in lean rats fed the same diet. Underdeveloped testes had 70 % less 22 : 5n-6 in PC and PE than normal-size testes. Results indicate that testicular fatty acid composition is sensitive to dietary fat modulations and especially obese rats responded more to dietary n-3 LCFA than their lean counterparts. The selective reduction in 22 : 5n-6 in underdeveloped testes indicates that 22 : 5n-6 is important in male reproduction in rats and requires further study to define the role of elongation and desaturation in testicular development.
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Furland NE, Luquez JM, Oresti GM, Aveldaño MI. Mild Testicular Hyperthermia Transiently Increases Lipid Droplet Accumulation and Modifies Sphingolipid and Glycerophospholipid Acyl Chains in the Rat Testis. Lipids 2011; 46:443-54. [DOI: 10.1007/s11745-011-3527-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 12/23/2010] [Indexed: 10/18/2022]
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Molday RS, Zhang K. Defective lipid transport and biosynthesis in recessive and dominant Stargardt macular degeneration. Prog Lipid Res 2010; 49:476-92. [PMID: 20633576 DOI: 10.1016/j.plipres.2010.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Stargardt disease is a common inherited macular degeneration characterized by a significant loss in central vision in the first or second decade of life, bilateral atrophic changes in the central retina associated with degeneration of photoreceptors and underlying retinal pigment epithelial cells, and the presence of yellow flecks extending from the macula. Autosomal recessive Stargardt disease, the most common macular dystrophy, is caused by mutations in the gene encoding ABCA4, a photoreceptor ATP binding cassette (ABC) transporter. Biochemical studies together with analysis of abca4 knockout mice and Stargardt patients have implicated ABCA4 as a lipid transporter that facilitates the removal of potentially toxic retinal compounds from photoreceptors following photoexcitation. An autosomal dominant form of Stargardt disease also known as Stargardt-like dystrophy is caused by mutations in a gene encoding ELOVL4, an enzyme that catalyzes the elongation of very long-chain fatty acids in photoreceptors and other tissues. This review focuses on the molecular characterization of ABCA4 and ELOVL4 and their role in photoreceptor cell biology and the pathogenesis of Stargardt disease.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre of Macular Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada.
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16
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Abstract
Stargardt-like macular degeneration (STGD3) is an early onset, autosomal dominant macular degeneration. STGD3 is characterized by a progressive pathology, the loss of central vision, atrophy of the retinal pigment epithelium, and accumulation of lipofuscin, clinical features that are also characteristic of age-related macular degeneration. The onset of clinical symptoms in STGD3, however, is typically observed within the second or third decade of life (i.e., starting in the teenage years). The clinical profile at any given age among STGD3 patients can be variable suggesting that, although STGD3 is a single gene defect, other genetic or environmental factors may play a role in moderating the final disease phenotype. Genetic studies localized the STGD3 disease locus to a small region on the short arm of human chromosome 6, and application of a positional candidate gene approach identified protein truncating mutations in the elongation of very long chain fatty acids-4 gene (ELOVL4) in patients with this disease. The ELOVL4 gene encodes a protein homologous to the ELO group of proteins that participate in fatty acid elongation in yeast. Pathogenic mutations found in the ELOVL4 gene result in altered trafficking of the protein and behave with a dominant negative effect. Mice carrying an Elovl4 mutation developed photoreceptor degeneration and depletion of very long chain fatty acids (VLCFA). ELOVL4 protein participates in the synthesis of fatty acids with chain length longer than 26 carbons. Studies on ELOVL4 indicate that VLCFA may be necessary for normal function of the retina, and the defective protein trafficking and/or altered VLCFA elongation underlies the pathology associated with STGD3. Determining the role of VLCFA in the retina and discerning the implications of abnormal trafficking of mutant ELOVL4 and depleted VLCFA content in the pathology of STGD3 will provide valuable insight in understanding the retinal structure, function, and pathology underlying STGD3 and may lead to a better understanding of the process of macular disease in general.
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Mateos MV, Salvador GA, Giusto NM. Selective localization of phosphatidylcholine-derived signaling in detergent-resistant membranes from synaptic endings. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:624-36. [PMID: 20026046 DOI: 10.1016/j.bbamem.2009.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 11/19/2009] [Accepted: 12/14/2009] [Indexed: 01/21/2023]
Abstract
Detergent-resistant membranes (DRMs) are a class of specialized microdomains that compartmentalize several signal transduction processes. In this work, DRMs were isolated from cerebral cortex synaptic endings (Syn) on the basis of their relative insolubility in cold Triton X-100 (1%). The lipid composition and marker protein content were analyzed in DRMs obtained from adult and aged animals. Both DRM preparations were enriched in Caveolin, Flotillin-1 and c-Src and also presented significantly higher sphingomyelin (SM) and cholesterol content than purified Syn. Total phospholipid-fatty acid composition presented an increase in 16:0 (35%), and a decrease in 20:4n-6 (67%) and 22:6n-3 (68%) content in DRM from adults when compared to entire synaptic endings. A more dramatic decrease was observed in the 20:4n-6 and 22:6n-3 content in DRMs from aged animals (80%) with respect to the results found in adults. The coexistence of phosphatidylcholine-specific-phospholipase C (PC-PLC) and phospholipase D (PLD) in Syn was previously reported. The presence of these signaling pathways was also investigated in DRMs isolated from adult and aged rats. Both PC-PLC and PLD pathways generate the lipid messenger diacylglycerol (DAG) by catalyzing PC hydrolysis. PC-PLC and PLD1 localization were increased in the DRM fraction. The increase in DAG generation (60%) in the presence of ethanol, confirmed that PC-PLC was also activated when compartmentalized in DRMs. Conversely, PLD2 was excluded from the DRM fraction. Our results show an age-related differential fatty acid composition and a selective localization of PC-derived signaling in synaptic DRMs obtained from adult and aged rats.
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Affiliation(s)
- M V Mateos
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, CC 857, B8000FWB Bahía Blanca, Argentina
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