2
|
Gindina S, Botsford B, Cowansage K, LeDoux J, Klann E, Hoeffer C, Ostroff L. Upregulation of eIF4E, but not other translation initiation factors, in dendritic spines during memory formation. J Comp Neurol 2021; 529:3112-3126. [PMID: 33864263 DOI: 10.1002/cne.25158] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/27/2021] [Accepted: 04/11/2021] [Indexed: 11/09/2022]
Abstract
Local translation can provide a rapid, spatially targeted supply of new proteins in distal dendrites to support synaptic changes that underlie learning. Learning and memory are especially sensitive to manipulations of translational control mechanisms, particularly those that target the initiation step, and translation initiation at synapses could be a means of maintaining synapse specificity during plasticity. Initiation predominantly occurs via recruitment of ribosomes to the 5' mRNA cap by complexes of eukaryotic initiation factors (eIFs), and the interaction between eIF4E and eIF4G1 is a particularly important target of translational control pathways. Pharmacological inhibition of eIF4E-eIF4G1 binding impairs formation of memory for aversive Pavlovian conditioning as well as the accompanying increase in polyribosomes in the heads of dendritic spines in the lateral amygdala (LA). This is consistent with a role for initiation at synapses in memory formation, but whether eIFs are even present near synapses is unknown. To determine whether dendritic spines contain eIFs and whether eIF distribution is affected by learning, we combined immunolabeling with serial section transmission electron microscopy (ssTEM) volume reconstructions of LA dendrites after Pavlovian conditioning. Labeling for eIF4E, eIF4G1, and eIF2α-another key target of regulation-occurred in roughly half of dendritic spines, but learning effects were only found for eIF4E, which was upregulated in the heads of dendritic spines. Our results support the possibility of regulated translation initiation as a means of synapse-specific protein targeting during learning and are consistent with the model of eIF4E availability as a central point of control.
Collapse
Affiliation(s)
- Sofya Gindina
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Benjamin Botsford
- Center for Neural Science, New York University, New York, New York, USA
| | - Kiriana Cowansage
- Center for Neural Science, New York University, New York, New York, USA
| | - Joseph LeDoux
- Center for Neural Science, New York University, New York, New York, USA.,Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York, USA
| | - Charles Hoeffer
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, USA
| | - Linnaea Ostroff
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| |
Collapse
|
6
|
Li S, Nguyen NUN, Xiao F, Menendez-Montes I, Nakada Y, Tan WLW, Anene-Nzelu CG, Foo RS, Thet S, Cardoso AC, Wang P, Elhelaly WM, Lam NT, Pereira AHM, Hill JA, Sadek HA. Mechanism of Eccentric Cardiomyocyte Hypertrophy Secondary to Severe Mitral Regurgitation. Circulation 2020; 141:1787-1799. [PMID: 32272846 DOI: 10.1161/circulationaha.119.043939] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Primary valvular heart disease is a prevalent cause of morbidity and mortality in both industrialized and developing countries. Although the primary consequence of valvular heart disease is myocardial dysfunction, treatment of valvular heart diseases centers around valve repair or replacement rather than prevention or reversal of myocardial dysfunction. This is particularly evident in primary mitral regurgitation (MR), which invariably results in eccentric hypertrophy and left ventricular (LV) failure in the absence of timely valve repair or replacement. The mechanism of LV dysfunction in primary severe MR is entirely unknown. METHODS Here, we developed the first mouse model of severe MR. Valvular damage was achieved by severing the mitral valve leaflets and chords with iridectomy scissors, and MR was confirmed by echocardiography. Serial echocardiography was performed to follow up LV morphology and systolic function. Analysis of cardiac tissues was subsequently performed to evaluate valve deformation, cardiomyocyte morphology, LV fibrosis, and cell death. Finally, dysregulated pathways were assessed by RNA-sequencing analysis and immunofluorescence. RESULTS In the ensuing 15 weeks after the induction of MR, gradual LV dilatation and dysfunction occurred, resulting in severe systolic dysfunction. Further analysis revealed that severe MR resulted in a marked increase in cardiac mass and increased cardiomyocyte length but not width, with electron microscopic evidence of sarcomere disarray and the development of sarcomere disruption. From a mechanistic standpoint, severe MR resulted in activation of multiple components of both the mammalian target of rapamycin and calcineurin pathways. Inhibition of mammalian target of rapamycin signaling preserved sarcomeric structure and prevented LV remodeling and systolic dysfunction. Immunohistochemical analysis uncovered a differential pattern of expression of the cell polarity regulator Crb2 (crumbs homolog 2) along the longitudinal axis of cardiomyocytes and close to the intercalated disks in the MR hearts. Electron microscopy images demonstrated a significant increase in polysome localization in close proximity to the intercalated disks and some areas along the longitudinal axis in the MR hearts. CONCLUSIONS These results indicate that LV dysfunction in response to severe MR is a form of maladaptive eccentric cardiomyocyte hypertrophy and outline the link between cell polarity regulation and spatial localization protein synthesis as a pathway for directional cardiomyocyte growth.
Collapse
Affiliation(s)
- Shujuan Li
- Department of Pediatric Cardiology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China (S.L.).,NHC Key Laboratory of Assisted Circulation (Sun Yat-sen University), Guangzhou, China (S.L.).,Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ngoc Uyen Nhi Nguyen
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Feng Xiao
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ivan Menendez-Montes
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Yuji Nakada
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Wilson Lek Wen Tan
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Chukwuemeka George Anene-Nzelu
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Roger S Foo
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Suwannee Thet
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Alisson Campos Cardoso
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo (A.C.C., A.H.M.P.)
| | - Ping Wang
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Waleed M Elhelaly
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Nicholas T Lam
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ana Helena Macedo Pereira
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo (A.C.C., A.H.M.P.)
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Department of Molecular Biology (J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Hesham A Sadek
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Center for Regenerative Science and Medicine (H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Department of Molecular Biology (J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| |
Collapse
|