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Organelle degradation in the lens by PLAAT phospholipases. Nature 2021; 592:634-638. [PMID: 33854238 DOI: 10.1038/s41586-021-03439-w] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/10/2021] [Indexed: 02/02/2023]
Abstract
The eye lens of vertebrates is composed of fibre cells in which all membrane-bound organelles undergo degradation during terminal differentiation to form an organelle-free zone1. The mechanism that underlies this large-scale organelle degradation remains largely unknown, although it has previously been shown to be independent of macroautophagy2,3. Here we report that phospholipases in the PLAAT (phospholipase A/acyltransferase, also known as HRASLS) family-Plaat1 (also known as Hrasls) in zebrafish and PLAAT3 (also known as HRASLS3, PLA2G16, H-rev107 or AdPLA) in mice4-6-are essential for the degradation of lens organelles such as mitochondria, the endoplasmic reticulum and lysosomes. Plaat1 and PLAAT3 translocate from the cytosol to various organelles immediately before organelle degradation, in a process that requires their C-terminal transmembrane domain. The translocation of Plaat1 to organelles depends on the differentiation of fibre cells and damage to organelle membranes, both of which are mediated by Hsf4. After the translocation of Plaat1 or PLAAT3 to membranes, the phospholipase induces extensive organelle rupture that is followed by complete degradation. Organelle degradation by PLAAT-family phospholipases is essential for achieving an optimal transparency and refractive function of the lens. These findings expand our understanding of intracellular organelle degradation and provide insights into the mechanism by which vertebrates acquired transparent lenses.
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Yang Y, Ma S, Wei F, Liang G, Yang X, Huang Y, Wang J, Zou Y. Pivotal role of cAMP-PKA-CREB signaling pathway in manganese-induced neurotoxicity in PC12 cells. ENVIRONMENTAL TOXICOLOGY 2019; 34:1052-1062. [PMID: 31161640 DOI: 10.1002/tox.22776] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/05/2019] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
Manganese (Mn) plays a critical role in individual growth and development, yet excessive exposure can result in neurotoxicity, especially cognitive impairment. Neuronal apoptosis is considered as one of the mechanisms of Mn-induced neurotoxicity. Recent evidence suggests that cAMP-PKA-CREB signaling regulates apoptosis and is associated with cognitive function. However, whether this pathway participates in Mn-induced neurotoxicity is not completely understood. To fill this gap, in vitro cultures of PC12 cells were exposed to 0, 400, 500, and 600 μmol/L Mn for 24 hours, respectively. Another group of cells were pretreated with 10.0 μmol/L rolipram (a phosphodiesterase-4 [PDE4] inhibitor) for 1 hour followed by 500 μmol/L Mn exposure for 24 hours. Flow cytometry, immunofluorescence staining, enzyme-linked immunosorbent assay, and Western blot analysis were used to detect the apoptosis rate, protein levels of PDE4, cAMP signaling, and apoptosis-associated proteins, respectively. We found that Mn exposure significantly inhibited cAMP signaling and protein expression of Bcl-2, while increasing apoptosis rate, protein levels of PDE4, Bax, activated caspase-3, and activated caspase-8 in PC12 cells. Pretreatment of rolipram ameliorated Mn-induced deficits in cAMP signaling and apoptosis. These findings demonstrate that cAMP-PKA-CREB signaling pathway-induced apoptosis is involved in Mn-induced neurotoxicity.
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Affiliation(s)
- Yiping Yang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Shuyan Ma
- Department of Toxicology, Shaanxi Provincial Center for Disease Control and Prevention, Xi'an, China
| | - Fu Wei
- Center for Reproductive Medicine and Genetics, The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Guiqiang Liang
- Department of Preventive Medicine, School of Public Health and Management, Guangxi University of Chinese Medicine, Nanning, China
| | - Xiaobo Yang
- Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, China
| | - Yuman Huang
- Guangxi Center for Disease Prevention and Control, Nanning, China
| | - Jian Wang
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
- Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, China
| | - Yunfeng Zou
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
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Hamdy MM, Mamiya T, Noda Y, Sayed M, Assi AA, Gomaa A, Yamada K, Nabeshima T. A selective phosphodiesterase IV inhibitor, rolipram blocks both withdrawal behavioral manifestations, and c-Fos protein expression in morphine dependent mice. Behav Brain Res 2001; 118:85-93. [PMID: 11163637 DOI: 10.1016/s0166-4328(00)00315-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated the effect of rolipram, a selective phosphodiesterase IV inhibitor, on morphine dependence in mice. The withdrawal manifestations were significantly reduced in mice that were treated with rolipram in combination with morphine repeatedly, compared to the mice treated with morphine and saline. Immunohistochemical study of c-Fos protein revealed a significant increase in the protein expression, 1 h after naloxone induced withdrawal manifestations. A combination of rolipram and morphine treatment for 5 days prevented the increase of c-Fos protein expression. Acute rolipram treatment prior to the naloxone challenge had no effect. Repeated treatment with rolipram itself had no effect either on behavior, or on c-Fos protein expression. These results suggest that chronic rolipram treatment in combination with morphine in mice will abolish the development of morphine dependence and the expression of c-Fos protein induced by naloxone challenge.
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Affiliation(s)
- M M Hamdy
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University, Graduate School of Medicine, 65 Tsuruma-cho, Showa-ku, 466-8560, Nagoya, Japan
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Affiliation(s)
- R M Pinder
- Scientific Development Group, Organon International BV, Oss, The Netherlands
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Kehne JH, Boulis NM, Davis M. Effects of the phosphodiesterase inhibitor rolipram on the acoustic startle response in rats. Psychopharmacology (Berl) 1991; 105:27-36. [PMID: 1660609 DOI: 10.1007/bf02316860] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Systemic administration of the phosphodiesterase inhibitor rolipram (0.05-10.0 mg/kg, IP) produced a rapid and dose-related increase in the amplitude of the acoustic startle response in rats. The (-) isomer was more potent than the (+) isomer in enhancing startle amplitude. Rolipram increased startle responses that were elicited by brief electrical stimulation of the ventral cochlear nucleus or nucleus reticularis pontis caudalis, two brainstem relay nuclei of the startle neural circuit. A low (5 micrograms) dose of rolipram produced an excitatory effect on startle following spinal (lumbar intrathecal) infusion but not following supraspinal (lateral ventricle) infusion. Rolipram (0.5 mg/kg, IP) excitation of startle was not blocked by drugs which differentially disrupt the release of monoamines (DSP4, reserpine + alpha-methyl-para-tyrosine, reserpine + para-chloro-phenylalanine) or by drugs which differentially block monoamine receptors (haloperidol, prazosin, idazoxan, cinanserin, or cyproheptadine). The marked increase in startle seen following systemic rolipram injection is attributable, at least in part, to an action in the lumbar spinal cord that directly or indirectly facilitates neural transmission along the reticulospinal component of the startle reflex neural pathway. The startle reflex should be a useful behavioral test system for studying the mechanism of action of rolipram and related compounds purported to selectively inhibit calmodulin-independent forms of phosphodiesterase.
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Affiliation(s)
- J H Kehne
- Yale University School of Medicine, Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven
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Koe BK, Lebel LA, Nielsen JA, Russo LL, Saccomano NA, Vinick FJ, Williams IH. Effects of novel catechol ether imidazolidinones on calcium-independent phosphodiesterase activity, [3H]rolipram binding, and reserpine-induced hypothermia in mice. Drug Dev Res 1990. [DOI: 10.1002/ddr.430210206] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Leroy MJ, Cedrin I, Breuiller M, Giovagrandi Y, Ferre F. Correlation between selective inhibition of the cyclic nucleotide phosphodiesterases and the contractile activity in human pregnant myometrium near term. Biochem Pharmacol 1989; 38:9-15. [PMID: 2535936 DOI: 10.1016/0006-2952(89)90142-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The present study was carried out to determine the ability of various pharmacological agents to selectively inhibit each cytosolic form of phosphodiesterase isolated from the longitudinal layer of human myometria near term. Among the drugs tested, zaprinast specifically inhibits the first form of PDE which hydrolyses both substrates (cAMP and cGMP) and is stimulated by the Ca2+-calmodulin complex. A second form of PDE specific for cAMP hydrolysis and Ca2+-calmodulin insensitive is only present during pregnancy. Rolipram is the most potent and selective inhibitor of this second form. It is also the most efficient compound to inhibit in vitro the spontaneous contractions of near term myometria. The double effect of rolipram suggests an important role of the second form of PDE in the mechanisms of contractility during the pregnancy. In addition rolipram or other derivatives might be of a therapeutic interest in the prevention of prematurity in so far as they are devoid of undesirable maternal and fetal side effects.
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Affiliation(s)
- M J Leroy
- INSERM U-166, Maternité Baudelocque, Paris, France
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Mustafa MR, Stolz JF, Luscombe DK. Effect of long-term rolipram administration on the sensitivity of alpha 2-adrenoceptors in rat brain. Eur J Pharmacol 1988; 148:171-7. [PMID: 2454198 DOI: 10.1016/0014-2999(88)90561-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of single and chronic doses of rolipram on the sensitivity of alpha 2-adrenoceptors have been compared with the phosphodiesterase inhibitors, isobutylmethylxanthine (IBMX) and ICI 63,197, and the antidepressant, desipramine. While pretreatment with a single dose of rolipram, ICI 63,197 or IBMX administered either 1 or 24 h prior to clonidine (0.1 mg/kg) enhanced clonidine-induced hypothermia and hypoactivity, chronic dosing (twice daily for 14 days) with desipramine (10 mg/kg) or rolipram (5 mg/kg) antagonized these behavioural effects. In contrast, chronic dosing with IBMX or ICI 63,197 failed to antagonize clonidine-induced hypothermia and hypoactivity. In binding studies neither ICI 63,197, IBMX, rolipram nor desipramine induced changes in the binding of 3H-labelled clonidine to rat cerebral cortical membranes following chronic administration. The failure of ICI 63,107 and IBMX to antagonize clonidine-induced hypothermia and hypoactivity suggests that the antidepressant effect of rolipram is independent of its phosphodiesterase inhibitor property.
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Affiliation(s)
- M R Mustafa
- Welsh School of Pharmacy, UWIST, Cardiff, U.K
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Flugy A, Novara V, Provenzano P, Cannizzaro G. Water-intake and conflict-behaviour after acute and chronic treatment with rolipram, a phosphodiesterase inhibitor; interaction with chlordiazepoxide. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/s0031-6989(88)80042-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Nowak G, Przegaliński E. Effect of repeated treatment with antidepressant drugs and electroconvulsive shock (ECS) on [3H] prazosin binding to different rat brain structures. J Neural Transm (Vienna) 1988; 71:57-64. [PMID: 2830364 DOI: 10.1007/bf01259410] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The influence of acute and repeated treatment with imipramine, amitriptyline, mianserin, citalopram and ECS on alpha 1-adrenoceptors in different structures of the rat brain (cerebral cortex, hippocampus and thalamus) was measured using [3H] prazosin as a ligand. Repeated, but not acute, treatment with all the above antidepressant drugs and ECS induced an increase in the density of alpha 1-adrenoceptors in the cerebral cortex. On the other hand, no changes were found in the hippocampus and thalamus, with an exception of the increased number of [3H] prazosin binding sites in the thalamus after imipramine. The results suggest that the up-regulation of alpha 1-adrenoceptors following repeated antidepressant treatment is not a general phenomenon within the central nervous system.
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Affiliation(s)
- G Nowak
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
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