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Liu P, Karim MR, Covelo A, Yue Y, Lee MK, Lin W. The UPR Maintains Proteostasis and the Viability and Function of Hippocampal Neurons in Adult Mice. Int J Mol Sci 2023; 24:11542. [PMID: 37511300 PMCID: PMC10380539 DOI: 10.3390/ijms241411542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
The unfolded protein response (UPR), which comprises three branches: PERK, ATF6α, and IRE1, is a major mechanism for maintaining cellular proteostasis. Many studies show that the UPR is a major player in regulating neuron viability and function in various neurodegenerative diseases; however, its role in neurodegeneration is highly controversial. Moreover, while evidence suggests activation of the UPR in neurons under normal conditions, deficiency of individual branches of the UPR has no major effect on brain neurons in animals. It remains unclear whether or how the UPR participates in regulating neuronal proteostasis under normal and disease conditions. To determine the physiological role of the UPR in neurons, we generated mice with double deletion of PERK and ATF6α in neurons. We found that inactivation of PERK and ATF6α in neurons caused lysosomal dysfunction (as evidenced by decreased expression of the V0a1 subunit of v-ATPase and decreased activation of cathepsin D), impairment of autophagic flux (as evidenced by increased ratio of LC3-II/LC3-I and increased p62 level), and accumulation of p-tau and Aβ42 in the hippocampus, and led to impairment of spatial memory, impairment of hippocampal LTP, and hippocampal degeneration in adult mice. These results suggest that the UPR is required for maintaining neuronal proteostasis (particularly tau and Aβ homeostasis) and the viability and function of neurons in the hippocampus of adult mice.
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Affiliation(s)
- Pingting Liu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Md Razaul Karim
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Ana Covelo
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yuan Yue
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Michael K Lee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
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Endoplasmic Reticulum Stress Signaling and Neuronal Cell Death. Int J Mol Sci 2022; 23:ijms232315186. [PMID: 36499512 PMCID: PMC9740965 DOI: 10.3390/ijms232315186] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/27/2022] [Accepted: 11/30/2022] [Indexed: 12/07/2022] Open
Abstract
Besides protein processing, the endoplasmic reticulum (ER) has several other functions such as lipid synthesis, the transfer of molecules to other cellular compartments, and the regulation of Ca2+ homeostasis. Before leaving the organelle, proteins must be folded and post-translationally modified. Protein folding and revision require molecular chaperones and a favorable ER environment. When in stressful situations, ER luminal conditions or chaperone capacity are altered, and the cell activates signaling cascades to restore a favorable folding environment triggering the so-called unfolded protein response (UPR) that can lead to autophagy to preserve cell integrity. However, when the UPR is disrupted or insufficient, cell death occurs. This review examines the links between UPR signaling, cell-protective responses, and death following ER stress with a particular focus on those mechanisms that operate in neurons.
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Kobayashi Y, Oguro A, Yagi E, Mitani A, Kudoh SN, Imaoka S. Bisphenol A and rotenone induce S-nitrosylation of protein disulfide isomerase (PDI) and inhibit neurite outgrowth of primary cultured cells of the rat hippocampus and PC12 cells. J Toxicol Sci 2021; 45:783-794. [PMID: 33268678 DOI: 10.2131/jts.45.783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Bisphenol A (BPA) interferes the function and development of the central nervous system (CNS), resulting in behavioral abnormalities and memory loss. S-nitrosylation of protein disulfide isomerase (PDI) is increased in brains with sporadic Alzheimer's disease and Parkinson's disease. The aim of the present study was to clarify the role of nitric oxide (NO) in BPA-induced neurotoxicity. Since rotenone induces NO-mediated neurodegeneration through S-nitrosylation of PDI, it was used as a positive control. First, rats were treated with BPA and rotenone, and S-nitrosylation of PDI was detected in rat brain microsomes. BPA and rotenone decreased RNase oxidation activity of PDI concomitant with S-nitrosylation of PDI. Next, to clarify S-nitrosylation of PDI by BPA and rotenone in rat brains, we treated the rat pheochromocytoma cell line PC12 and primary cultured neuron cells from the rat hippocampus with BPA (5 and 10 μM) and rotenone (100 or 200 nM). BPA induced S-nitrosylation of PDI, while NG-monomethyl-L-arginine (L-NMMA), a NOS inhibitor, exerted the opposite effects. Finally, to evaluate the toxicity of BPA in the CNS, we investigated its effects on neurite outgrowth of PC12 and primary cultured neuron cells. BPA inhibited neurite outgrowth of these cells, while L-NMMA reversed this inhibition. The involvement of PDI activity in neurite outgrowth was also examined, and bacitracin, a PDI inhibitor, is shown to decrease neurite outgrowth. Furthermore, the overexpression of PDI, but not a catalytically inactive PDI mutant, enhanced neurite outgrowth. These results suggested that S-nitrosylation of PDI induced by excessive NO caused BPA-induced neurotoxicity.
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Affiliation(s)
- Yukino Kobayashi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
| | - Ami Oguro
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University.,Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University
| | - Erina Yagi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
| | - Akira Mitani
- Department of Human-System Interaction, School of Science and Technology, Kwansei Gakuin University
| | - Suguru N Kudoh
- Department of Human-System Interaction, School of Science and Technology, Kwansei Gakuin University
| | - Susumu Imaoka
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
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Thomson S, Waters KA, Machaalani R. The Unfolded Protein Response in the Human Infant Brain and Dysregulation Seen in Sudden Infant Death Syndrome (SIDS). Mol Neurobiol 2021; 58:2242-2255. [PMID: 33417217 DOI: 10.1007/s12035-020-02244-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/02/2020] [Indexed: 10/22/2022]
Abstract
Low orexin levels in the hypothalamus, and abnormal brainstem expression levels of many neurotransmitter and receptor systems in infants who died suddenly during a sleep period and diagnosed as sudden infant death syndrome (SIDS), may be linked to abnormal protein unfolding. We studied neuronal expression of the three unfolded protein response (UPR) pathways in the human infant brainstem, hypothalamus, and cerebellum: activating transcription factor 6 (ATF6), phosphorylated inositol-requiring enzyme 1 (IRE1), and phosphorylated protein-kinase (PKR)-like endoplasmic reticulum (ER) kinase (pPERK). Percentages of positively stained neurons were examined via immunohistochemistry and compared between SIDS (n = 28) and non-SIDS (n = 12) infant deaths. Further analysis determined the effects of the SIDS risk factors including cigarette smoke exposure, bed-sharing, prone sleeping, and an upper respiratory tract infection (URTI). Compared to non-SIDS, SIDS infants had higher ATF6 in the inferior olivary and hypoglossal nuclei of the medulla, higher pIRE1 in the dentate nucleus of the cerebellum, and higher pPERK in the cuneate nucleus and hypothalamus. Infants who were found prone had higher ATF6 in the hypoglossal and the locus coeruleus of the pons. Infants exposed to cigarette smoke had higher ATF6 in the vestibular and cuneate nuclei of the medulla. Infants who were bed-sharing had higher pPERK in the dorsal raphe nuclei of the pons and the Purkinje cells of the cerebellum. This study indicates that subgroups of SIDS infants, defined by risk exposure, had activation of the UPR in several nuclei relating to proprioception and motor control, suggesting that the UPR underlies the neuroreceptor system changes responsible for these physiological functions, leading to compromise in the pathogenesis of SIDS.
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Affiliation(s)
- Shannon Thomson
- Discipline of Medicine, Central Clinical School, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Karen A Waters
- Discipline of Medicine, Central Clinical School, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.,Discipline of Child and Adolescent Health, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Rita Machaalani
- Discipline of Medicine, Central Clinical School, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia. .,Discipline of Child and Adolescent Health, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.
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Wang L, Liu L, Ying L, Wang L. Honokiol inhibits inflammation and endoplasmic reticulum stress in a rat model of pregnancy-induced hypertension. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2019.1707710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Affiliation(s)
- Lihui Wang
- Department of Obstetrics and Gynecology, Zhe Jiang Chinese Medicine and Western Medicine Integrated Hospital, Hangzhou, Zhejiang, China
| | - Ling Liu
- Department of Obstetrics and Gynecology, Zhe Jiang Chinese Medicine and Western Medicine Integrated Hospital, Hangzhou, Zhejiang, China
| | - Lijie Ying
- Department of Obstetrics and Gynecology, Zhe Jiang Chinese Medicine and Western Medicine Integrated Hospital, Hangzhou, Zhejiang, China
| | - Li Wang
- Department of Obstetrics and Gynecology, Zhe Jiang Chinese Medicine and Western Medicine Integrated Hospital, Hangzhou, Zhejiang, China
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