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Lockshin ER, Calakos N. The integrated stress response in brain diseases: A double-edged sword for proteostasis and synapses. Curr Opin Neurobiol 2024; 87:102886. [PMID: 38901329 DOI: 10.1016/j.conb.2024.102886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/22/2024]
Abstract
The integrated stress response (ISR) is a highly conserved biochemical pathway that regulates protein synthesis. The ISR is activated in response to diverse stressors to restore cellular homeostasis. As such, the ISR is implicated in a wide range of diseases, including brain disorders. However, in the brain, the ISR also has potent influence on processes beyond proteostasis, namely synaptic plasticity, learning and memory. Thus, in the setting of brain diseases, ISR activity may have dual effects on proteostasis and synaptic function. In this review, we consider the ISR's contribution to brain disorders through the lens of its potential effects on synaptic plasticity. From these examples, we illustrate that at times ISR activity may be a "double-edged sword". We also highlight its potential as a therapeutic target to improve circuit function in brain diseases independent of its role in disease pathogenesis.
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Affiliation(s)
- Elana R Lockshin
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Nicole Calakos
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA; Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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2
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Abstract
The brain is designed not only with molecules and cellular processes that help to form memories but also with molecules and cellular processes that suppress the formation and retention of memory. The latter processes are critical for an efficient memory management system, given the vast amount of information that each person experiences in their daily activities and that most of this information becomes irrelevant with time. Thus, efficiency dictates that the brain should have processes for selecting the most critical information for storage and suppressing the irrelevant or forgetting it later should it escape the initial filters. Such memory suppressor molecules and processes are revealed by genetic or pharmacologic insults that lead to enhanced memory expression. We review here the predominant memory suppressor molecules and processes that have recently been discovered. They are diverse, as expected, because the brain is complex and employs many different strategies and mechanisms to form memories. They include the gene-repressive actions of small noncoding RNAs, repressors of protein synthesis, cAMP-mediated gene expression pathways, inter- and intracellular signaling pathways for normal forgetting, and others. A deep understanding of memory suppressor molecules and processes is necessary to fully comprehend how the brain forms, stabilizes, and retrieves memories and to reveal how brain disorders disrupt memory.
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Affiliation(s)
- Nathaniel C. Noyes
- Department of Neuroscience, University of Florida Scripps Biomedical Research, Jupiter, FL, USA
| | - Ronald L. Davis
- Department of Neuroscience, University of Florida Scripps Biomedical Research, Jupiter, FL, USA
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3
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Volloch V, Rits-Volloch S. ACH2.0/E, the Consolidated Theory of Conventional and Unconventional Alzheimer's Disease: Origins, Progression, and Therapeutic Strategies. Int J Mol Sci 2024; 25:6036. [PMID: 38892224 PMCID: PMC11172602 DOI: 10.3390/ijms25116036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
The centrality of amyloid-beta (Aβ) is an indisputable tenet of Alzheimer's disease (AD). It was initially indicated by the detection (1991) of a mutation within Aβ protein precursor (AβPP) segregating with the disease, which served as a basis for the long-standing Amyloid Cascade Hypothesis (ACH) theory of AD. In the intervening three decades, this notion was affirmed and substantiated by the discovery of numerous AD-causing and AD-protective mutations with all, without an exception, affecting the structure, production, and intraneuronal degradation of Aβ. The ACH postulated that the disease is caused and driven by extracellular Aβ. When it became clear that this is not the case, and the ACH was largely discredited, a new theory of AD, dubbed ACH2.0 to re-emphasize the centrality of Aβ, was formulated. In the ACH2.0, AD is caused by physiologically accumulated intraneuronal Aβ (iAβ) derived from AβPP. Upon reaching the critical threshold, it triggers activation of the autonomous AβPP-independent iAβ generation pathway; its output is retained intraneuronally and drives the AD pathology. The bridge between iAβ derived from AβPP and that generated independently of AβPP is the neuronal integrated stress response (ISR) elicited by the former. The ISR severely suppresses cellular protein synthesis; concurrently, it activates the production of a small subset of proteins, which apparently includes components necessary for operation of the AβPP-independent iAβ generation pathway that are absent under regular circumstances. The above sequence of events defines "conventional" AD, which is both caused and driven by differentially derived iAβ. Since the ISR can be elicited by a multitude of stressors, the logic of the ACH2.0 mandates that another class of AD, referred to as "unconventional", has to occur. Unconventional AD is defined as a disease where a stressor distinct from AβPP-derived iAβ elicits the neuronal ISR. Thus, the essence of both, conventional and unconventional, forms of AD is one and the same, namely autonomous, self-sustainable, AβPP-independent production of iAβ. What distinguishes them is the manner of activation of this pathway, i.e., the mode of causation of the disease. In unconventional AD, processes occurring at locations as distant from and seemingly as unrelated to the brain as, say, the knee can potentially trigger the disease. The present study asserts that these processes include traumatic brain injury (TBI), chronic traumatic encephalopathy, viral and bacterial infections, and a wide array of inflammatory conditions. It considers the pathways which are common to all these occurrences and culminate in the elicitation of the neuronal ISR, analyzes the dynamics of conventional versus unconventional AD, shows how the former can morph into the latter, explains how a single TBI can hasten the occurrence of AD and why it takes multiple TBIs to trigger the disease, and proposes the appropriate therapeutic strategies. It posits that yet another class of unconventional AD may occur where the autonomous AβPP-independent iAβ production pathway is initiated by an ISR-unrelated activator, and consolidates the above notions in a theory of AD, designated ACH2.0/E (for expanded ACH2.0), which incorporates the ACH2.0 as its special case and retains the centrality of iAβ produced independently of AβPP as the driving agent of the disease.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Yalala S, Gondane A, Poulose N, Liang J, Mills IG, Itkonen HM. CDK9 inhibition activates innate immune response through viral mimicry. FASEB J 2024; 38:e23628. [PMID: 38661032 DOI: 10.1096/fj.202302375r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 04/26/2024]
Abstract
Cancer cells frequently exhibit hyperactivation of transcription, which can lead to increased sensitivity to compounds targeting the transcriptional kinases, in particular CDK9. However, mechanistic details of CDK9 inhibition-induced cancer cell-selective anti-proliferative effects remain largely unknown. Here, we discover that CDK9 inhibition activates the innate immune response through viral mimicry in cancer cells. In MYC over-expressing prostate cancer cells, CDK9 inhibition leads to the gross accumulation of mis-spliced RNA. Double-stranded RNA (dsRNA)-activated kinase can recognize these mis-spliced RNAs, and we show that the activity of this kinase is required for the CDK9 inhibitor-induced anti-proliferative effects. Using time-resolved transcriptional profiling (SLAM-seq), targeted proteomics, and ChIP-seq, we show that, similar to viral infection, CDK9 inhibition significantly suppresses transcription of most genes but allows selective transcription and translation of cytokines related to the innate immune response. In particular, CDK9 inhibition activates NFκB-driven cytokine signaling at the transcriptional and secretome levels. The transcriptional signature induced by CDK9 inhibition identifies prostate cancers with a high level of genome instability. We propose that it is possible to induce similar effects in patients using CDK9 inhibition, which, we show, causes DNA damage in vitro. In the future, it is important to establish whether CDK9 inhibitors can potentiate the effects of immunotherapy against late-stage prostate cancer, a currently lethal disease.
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Affiliation(s)
- Shivani Yalala
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Aishwarya Gondane
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ninu Poulose
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jing Liang
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ian G Mills
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Harri M Itkonen
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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5
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Nam KH, Ordureau A. How does the neuronal proteostasis network react to cellular cues? Biochem Soc Trans 2024; 52:581-592. [PMID: 38488108 DOI: 10.1042/bst20230316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/25/2024]
Abstract
Even though neurons are post-mitotic cells, they still engage in protein synthesis to uphold their cellular content balance, including for organelles, such as the endoplasmic reticulum or mitochondria. Additionally, they expend significant energy on tasks like neurotransmitter production and maintaining redox homeostasis. This cellular homeostasis is upheld through a delicate interplay between mRNA transcription-translation and protein degradative pathways, such as autophagy and proteasome degradation. When faced with cues such as nutrient stress, neurons must adapt by altering their proteome to survive. However, in many neurodegenerative disorders, such as Parkinson's disease, the pathway and processes for coping with cellular stress are impaired. This review explores neuronal proteome adaptation in response to cellular stress, such as nutrient stress, with a focus on proteins associated with autophagy, stress response pathways, and neurotransmitters.
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Affiliation(s)
- Ki Hong Nam
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
| | - Alban Ordureau
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
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Guo SK, Liu CX, Xu YF, Wang X, Nan F, Huang Y, Li S, Nan S, Li L, Kon E, Li C, Wei MY, Su R, Wei J, Peng S, Ad-El N, Liu J, Peer D, Chen T, Yang L, Chen LL. Therapeutic application of circular RNA aptamers in a mouse model of psoriasis. Nat Biotechnol 2024:10.1038/s41587-024-02204-4. [PMID: 38653797 DOI: 10.1038/s41587-024-02204-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/12/2024] [Indexed: 04/25/2024]
Abstract
Efforts to advance RNA aptamers as a new therapeutic modality have been limited by their susceptibility to degradation and immunogenicity. In a previous study, we demonstrated synthesized short double-stranded region-containing circular RNAs (ds-cRNAs) with minimal immunogenicity targeted to dsRNA-activated protein kinase R (PKR). Here we test the therapeutic potential of ds-cRNAs in a mouse model of imiquimod-induced psoriasis. We find that genetic supplementation of ds-cRNAs leads to inhibition of PKR, resulting in alleviation of downstream interferon-α and dsRNA signals and attenuation of psoriasis phenotypes. Delivery of ds-cRNAs by lipid nanoparticles to the spleen attenuates PKR activity in examined splenocytes, resulting in reduced epidermal thickness. These findings suggest that ds-cRNAs represent a promising approach to mitigate excessive PKR activation for therapeutic purposes.
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Affiliation(s)
- Si-Kun Guo
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chu-Xiao Liu
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yi-Feng Xu
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiao Wang
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Fang Nan
- Center for Molecular Medicine, Children's Hospital of Fudan University and Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Youkui Huang
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Siqi Li
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shan Nan
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ling Li
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Edo Kon
- Laboratory of Precision Nanomedicine, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Department of Materials Sciences and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Center for Nanoscience and Nanotechnology, Cancer Biology Research Center, Tel Aviv University, Tel Aviv, Israel
| | - Chen Li
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Meng-Yuan Wei
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rina Su
- Department of Dermatology, Beijing Chao-yang Hospital, Capital Medical University, Beijing, China
| | - Jia Wei
- Center for Molecular Medicine, Children's Hospital of Fudan University and Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Shiguang Peng
- Department of Dermatology, Beijing Chao-yang Hospital, Capital Medical University, Beijing, China
| | - Nitay Ad-El
- Laboratory of Precision Nanomedicine, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Department of Materials Sciences and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Center for Nanoscience and Nanotechnology, Cancer Biology Research Center, Tel Aviv University, Tel Aviv, Israel
| | - Jiaquan Liu
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Dan Peer
- Laboratory of Precision Nanomedicine, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Department of Materials Sciences and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Center for Nanoscience and Nanotechnology, Cancer Biology Research Center, Tel Aviv University, Tel Aviv, Israel
| | - Ting Chen
- National Institute of Biological Sciences, Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Li Yang
- Center for Molecular Medicine, Children's Hospital of Fudan University and Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Ling-Ling Chen
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- New Cornerstone Science Laboratory, Shenzhen, China.
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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7
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Hashimoto Y, Tokumoto Y, Watanabe T, Ogi Y, Sugishita H, Akita S, Niida K, Hayashi M, Okada M, Shiraishi K, Tange K, Tomida H, Yamamoto Y, Takeshita E, Ikeda Y, Oshikiri T, Hiasa Y. C16, a PKR inhibitor, suppresses cell proliferation by regulating the cell cycle via p21 in colorectal cancer. Sci Rep 2024; 14:9029. [PMID: 38641657 PMCID: PMC11031597 DOI: 10.1038/s41598-024-59671-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/12/2024] [Indexed: 04/21/2024] Open
Abstract
Double-stranded RNA-activated protein kinase R (PKR) is highly expressed in colorectal cancer (CRC). However, the role of PKR in CRC remains unclear. The aim of this study was to clarify whether C16 (a PKR inhibitor) exhibits antitumor effects and to identify its target pathway in CRC. We evaluated the effects of C16 on CRC cell lines using the MTS assay. Enrichment analysis was performed to identify the target pathway of C16. The cell cycle was analyzed using flow cytometry. Finally, we used immunohistochemistry to examine human CRC specimens. C16 suppressed the proliferation of CRC cells. Gene Ontology (GO) analysis revealed that the cell cycle-related GO category was substantially enriched in CRC cells treated with C16. C16 treatment resulted in G1 arrest and increased p21 protein and mRNA expression. Moreover, p21 expression was associated with CRC development as observed using immunohistochemical analysis of human CRC tissues. C16 upregulates p21 expression in CRC cells to regulate cell cycle and suppress tumor growth. Thus, PKR inhibitors may serve as a new treatment option for patients with CRC.
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Affiliation(s)
- Yu Hashimoto
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yoshio Tokumoto
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
| | - Takao Watanabe
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yusuke Ogi
- Department of Gastrointestinal Surgery and Surgical Oncology, Ehime University Graduate School of Medicine, Toon, Ehime, 791-0295, Japan
| | - Hiroki Sugishita
- Department of Gastrointestinal Surgery and Surgical Oncology, Ehime University Graduate School of Medicine, Toon, Ehime, 791-0295, Japan
| | - Satoshi Akita
- Department of Minimally Invasive Gastroenterology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Kazuki Niida
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Mirai Hayashi
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Masaya Okada
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Kana Shiraishi
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Kazuhiro Tange
- Department of Inflammatory Bowel Diseases and Therapeutics, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Hideomi Tomida
- Endoscopy Center, Ehime University Hospital, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yasunori Yamamoto
- Endoscopy Center, Ehime University Hospital, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Eiji Takeshita
- Department of Inflammatory Bowel Diseases and Therapeutics, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yoshio Ikeda
- Endoscopy Center, Ehime University Hospital, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Taro Oshikiri
- Department of Gastrointestinal Surgery and Surgical Oncology, Ehime University Graduate School of Medicine, Toon, Ehime, 791-0295, Japan
| | - Yoichi Hiasa
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan
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8
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Volloch V, Rits-Volloch S. On the Inadequacy of the Current Transgenic Animal Models of Alzheimer's Disease: The Path Forward. Int J Mol Sci 2024; 25:2981. [PMID: 38474228 PMCID: PMC10932000 DOI: 10.3390/ijms25052981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
For at least two reasons, the current transgenic animal models of Alzheimer's disease (AD) appear to be patently inadequate. They may be useful in many respects, the AD models; however, they are not. First, they are incapable of developing the full spectrum of the AD pathology. Second, they respond spectacularly well to drugs that are completely ineffective in the treatment of symptomatic AD. These observations indicate that both the transgenic animal models and the drugs faithfully reflect the theory that guided the design and development of both, the amyloid cascade hypothesis (ACH), and that both are inadequate because their underlying theory is. This conclusion necessitated the formulation of a new, all-encompassing theory of conventional AD-the ACH2.0. The two principal attributes of the ACH2.0 are the following. One, in conventional AD, the agent that causes the disease and drives its pathology is the intraneuronal amyloid-β (iAβ) produced in two distinctly different pathways. Two, following the commencement of AD, the bulk of Aβ is generated independently of Aβ protein precursor (AβPP) and is retained inside the neuron as iAβ. Within the framework of the ACH2.0, AβPP-derived iAβ accumulates physiologically in a lifelong process. It cannot reach levels required to support the progression of AD; it does, however, cause the disease. Indeed, conventional AD occurs if and when the levels of AβPP-derived iAβ cross the critical threshold, elicit the neuronal integrated stress response (ISR), and trigger the activation of the AβPP-independent iAβ generation pathway; the disease commences only when this pathway is operational. The iAβ produced in this pathway reaches levels sufficient to drive the AD pathology; it also propagates its own production and thus sustains the activity of the pathway and perpetuates its operation. The present study analyzes the reason underlying the evident inadequacy of the current transgenic animal models of AD. It concludes that they model, in fact, not Alzheimer's disease but rather the effects of the neuronal ISR sustained by AβPP-derived iAβ, that this is due to the lack of the operational AβPP-independent iAβ production pathway, and that this mechanism must be incorporated into any successful AD model faithfully emulating the disease. The study dissects the plausible molecular mechanisms of the AβPP-independent iAβ production and the pathways leading to their activation, and introduces the concept of conventional versus unconventional Alzheimer's disease. It also proposes the path forward, posits the principles of design of productive transgenic animal models of the disease, and describes the molecular details of their construction.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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9
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Oliveira MM, Mohamed M, Elder MK, Banegas-Morales K, Mamcarz M, Lu EH, Golhan EAN, Navrange N, Chatterjee S, Abel T, Klann E. The integrated stress response effector GADD34 is repurposed by neurons to promote stimulus-induced translation. Cell Rep 2024; 43:113670. [PMID: 38219147 PMCID: PMC10964249 DOI: 10.1016/j.celrep.2023.113670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/11/2023] [Accepted: 12/26/2023] [Indexed: 01/16/2024] Open
Abstract
Neuronal protein synthesis is required for long-lasting plasticity and long-term memory consolidation. Dephosphorylation of eukaryotic initiation factor 2α is one of the key translational control events that is required to increase de novo protein synthesis that underlies long-lasting plasticity and memory consolidation. Here, we interrogate the molecular pathways of translational control that are triggered by neuronal stimulation with brain-derived neurotrophic factor (BDNF), which results in eukaryotic initiation factor 2α (eIF2α) dephosphorylation and increases in de novo protein synthesis. Primary rodent neurons exposed to BDNF display elevated translation of GADD34, which facilitates eIF2α dephosphorylation and subsequent de novo protein synthesis. Furthermore, GADD34 requires G-actin generated by cofilin to dephosphorylate eIF2α and enhance protein synthesis. Finally, GADD34 is required for BDNF-induced translation of synaptic plasticity-related proteins. Overall, we provide evidence that neurons repurpose GADD34, an effector of the integrated stress response, as an orchestrator of rapid increases in eIF2-dependent translation in response to plasticity-inducing stimuli.
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Affiliation(s)
| | - Muhaned Mohamed
- Center for Neural Science, New York University, New York, NY, USA
| | - Megan K Elder
- Center for Neural Science, New York University, New York, NY, USA
| | | | - Maggie Mamcarz
- Center for Neural Science, New York University, New York, NY, USA
| | - Emily H Lu
- Center for Neural Science, New York University, New York, NY, USA
| | - Ela A N Golhan
- Center for Neural Science, New York University, New York, NY, USA
| | - Nishika Navrange
- Center for Neural Science, New York University, New York, NY, USA
| | - Snehajyoti Chatterjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University School of Medicine, New York, NY, USA.
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10
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Sadeq S, Chitcharoen S, Al-Hashimi S, Rattanaburi S, Casement J, Werner A. Significant Variations in Double-Stranded RNA Levels in Cultured Skin Cells. Cells 2024; 13:226. [PMID: 38334619 PMCID: PMC10854852 DOI: 10.3390/cells13030226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
Endogenous double-stranded RNA has emerged as a potent stimulator of innate immunity. Under physiological conditions, endogenous dsRNA is maintained in the cell nucleus or the mitochondria; however, if protective mechanisms are breached, it leaches into the cytoplasm and triggers immune signaling pathways. Ectopic activation of innate immune pathways is associated with various diseases and senescence and can trigger apoptosis. Hereby, the level of cytoplasmic dsRNA is crucial. We have enriched dsRNA from two melanoma cell lines and primary dermal fibroblasts, including a competing probe, and analyzed the dsRNA transcriptome using RNA sequencing. There was a striking difference in read counts between the cell lines and the primary cells, and the effect was confirmed by northern blotting and immunocytochemistry. Both mitochondria (10-20%) and nuclear transcription (80-90%) contributed significantly to the dsRNA transcriptome. The mitochondrial contribution was lower in the cancer cells compared to fibroblasts. The expression of different transposable element families was comparable, suggesting a general up-regulation of transposable element expression rather than stimulation of a specific sub-family. Sequencing of the input control revealed minor differences in dsRNA processing pathways with an upregulation of oligoadenylate synthase and RNP125 that negatively regulates the dsRNA sensors RIG1 and MDA5. Moreover, RT-qPCR, Western blotting, and immunocytochemistry confirmed the relatively minor adaptations to the hugely different dsRNA levels. As a consequence, these transformed cell lines are potentially less tolerant to interventions that increase the formation of endogenous dsRNA.
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Affiliation(s)
- Shaymaa Sadeq
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (S.S.); (S.A.-H.)
- Fallujah College of Medicine, University of Fallujah, Al-Fallujah 31002, Iraq
| | - Suwalak Chitcharoen
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand;
- Center of Excellence in Systems Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Surar Al-Hashimi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (S.S.); (S.A.-H.)
- College of Medicine, University of Misan, Al-Sader Teaching Hospital, Amarah 62001, Iraq
| | - Somruthai Rattanaburi
- Center of Excellence in Systems Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand;
| | - John Casement
- Bioinformatics Support Unit, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK;
| | - Andreas Werner
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (S.S.); (S.A.-H.)
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11
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Boone M, Zappa F. Signaling plasticity in the integrated stress response. Front Cell Dev Biol 2023; 11:1271141. [PMID: 38143923 PMCID: PMC10740175 DOI: 10.3389/fcell.2023.1271141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023] Open
Abstract
The Integrated Stress Response (ISR) is an essential homeostatic signaling network that controls the cell's biosynthetic capacity. Four ISR sensor kinases detect multiple stressors and relay this information to downstream effectors by phosphorylating a common node: the alpha subunit of the eukaryotic initiation factor eIF2. As a result, general protein synthesis is repressed while select transcripts are preferentially translated, thus remodeling the proteome and transcriptome. Mounting evidence supports a view of the ISR as a dynamic signaling network with multiple modulators and feedback regulatory features that vary across cell and tissue types. Here, we discuss updated views on ISR sensor kinase mechanisms, how the subcellular localization of ISR components impacts signaling, and highlight ISR signaling differences across cells and tissues. Finally, we consider crosstalk between the ISR and other signaling pathways as a determinant of cell health.
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12
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Castillo PE, Jung H, Klann E, Riccio A. Presynaptic Protein Synthesis in Brain Function and Disease. J Neurosci 2023; 43:7483-7488. [PMID: 37940588 PMCID: PMC10634577 DOI: 10.1523/jneurosci.1454-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/10/2023] [Accepted: 08/15/2023] [Indexed: 11/10/2023] Open
Abstract
Local protein synthesis in mature brain axons regulates the structure and function of presynaptic boutons by adjusting the presynaptic proteome to local demands. This crucial mechanism underlies experience-dependent modifications of brain circuits, and its dysregulation may contribute to brain disorders, such as autism and intellectual disability. Here, we discuss recent advancements in the axonal transcriptome, axonal RNA localization and translation, and the role of presynaptic local translation in synaptic plasticity and memory.
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Affiliation(s)
- Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Hosung Jung
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York 10003
- New York University Neuroscience Institute, New York University Grossman School of Medicine, New York, New York 10016
| | - Antonella Riccio
- UCL Laboratory for Molecular Cell Biology University College London, London, WC1E 6BT, United Kingdom
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13
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Shah SB, Peddada TN, Song C, Mensah M, Sung H, Yavi M, Yuan P, Zarate CA, Mickey BJ, Burmeister M, Akula N, McMahon FJ. Exome-wide association study of treatment-resistant depression suggests novel treatment targets. Sci Rep 2023; 13:12467. [PMID: 37528149 PMCID: PMC10394052 DOI: 10.1038/s41598-023-38984-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/18/2023] [Indexed: 08/03/2023] Open
Abstract
Treatment-resistant depression (TRD) is a severe form of major depressive disorder (MDD) with substantial public health impact and poor treatment outcome. Treatment outcome in MDD is significantly heritable, but genome-wide association studies have failed to identify replicable common marker alleles, suggesting a potential role for uncommon variants. Here we investigated the hypothesis that uncommon, putatively functional genetic variants are associated with TRD. Whole-exome sequencing data was obtained from 182 TRD cases and 2021 psychiatrically healthy controls. After quality control, the remaining 149 TRD cases and 1976 controls were analyzed with tests designed to detect excess burdens of uncommon variants. At the gene level, 5 genes, ZNF248, PRKRA, PYHIN1, SLC7A8, and STK19 each carried exome-wide significant excess burdens of variants in TRD cases (q < 0.05). Analysis of 41 pre-selected gene sets suggested an excess of uncommon, functional variants among genes involved in lithium response. Among the genes identified in previous TRD studies, ZDHHC3 was also significant in this sample after multiple test correction. ZNF248 and STK19 are involved in transcriptional regulation, PHYIN1 and PRKRA are involved in immune response, SLC7A8 is associated with thyroid hormone transporter activity, and ZDHHC3 regulates synaptic clustering of GABA and glutamate receptors. These results implicate uncommon, functional alleles in TRD and suggest promising novel targets for future research.
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Affiliation(s)
- Shrey B Shah
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
- Rutgers New Jersey Medical School, Newark, NJ, USA.
| | - Teja N Peddada
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
- Stanford University School of Medicine, Stanford, CA, USA
| | - Christopher Song
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Maame Mensah
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Heejong Sung
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Mani Yavi
- Experimental Therapeutics and Pathophysiology Branch and Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Peixiong Yuan
- Experimental Therapeutics and Pathophysiology Branch and Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Carlos A Zarate
- Experimental Therapeutics and Pathophysiology Branch and Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Brian J Mickey
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, USA
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Margit Burmeister
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
- Michigan Neuroscience Institute and Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Nirmala Akula
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Francis J McMahon
- Human Genetics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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14
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Mekiten O, Yitzhaky A, Gould N, Rosenblum K, Hertzberg L. Ribosome subunits are upregulated in brain samples of a subgroup of individuals with schizophrenia: A systematic gene expression meta-analysis. J Psychiatr Res 2023; 164:372-381. [PMID: 37413782 DOI: 10.1016/j.jpsychires.2023.06.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/05/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023]
Abstract
One of the new theories accounting for the underlying pathophysiology of schizophrenia is excitation/inhibition imbalance. Interestingly, perturbation in protein synthesis machinery as well as oxidative stress can lead to excitation/inhibition imbalance. We thus performed a systematic meta-analysis of the expression of 79 ribosome subunit genes and two oxidative-stress related genes, HIF1A and NQO1, in brain samples of individuals with schizophrenia vs. healthy controls. We integrated 12 gene expression datasets, following the PRISMA guidelines (overall 511 samples, 253 schizophrenia and 258 controls). Five ribosome subunit genes were significantly upregulated in a subgroup of the patients with schizophrenia, while 24 (30%) showed a tendency for upregulation. HIF1A and NQO1 were also found to be significantly upregulated. Moreover, HIF1A and NQO1 showed positive correlation with the expression of the upregulated ribosome subunit genes. Our results, together with previous findings, suggest a possible role for altered mRNA translation in the pathogenesis of schizophrenia, in association with markers of increased oxidative stress in a subgroup of patients. Further studies should define whether the upregulation of ribosome subunits result in altered mRNA translation, which proteins are modulated and how it characterizes a subgroup of the patients with schizophrenia.
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Affiliation(s)
- Ori Mekiten
- Faculty of Medicine, Tel-Aviv University, Israel
| | - Assif Yitzhaky
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
| | - Nathaniel Gould
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel; Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
| | - Libi Hertzberg
- Faculty of Medicine, Tel-Aviv University, Israel; Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel; Shalvata Mental Health Center, Israel.
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15
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Carreras I, Jung Y, Lopez-Benitez J, Tognoni CM, Dedeoglu A. Fingolimod mitigates memory loss in a mouse model of Gulf War Illness amid decreasing the activation of microglia, protein kinase R, and NFκB. Neurotoxicology 2023; 96:197-206. [PMID: 37160207 PMCID: PMC10334821 DOI: 10.1016/j.neuro.2023.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/05/2023] [Accepted: 05/05/2023] [Indexed: 05/11/2023]
Abstract
Gulf War Illness (GWI) is an unrelenting multi-symptom illness with chronic central nervous system and peripheral pathology affecting veterans from the 1991 Gulf War and for which effective treatment is lacking. An increasing number of studies indicate that persistent neuroinflammation is likely the underlying cause of cognitive and mood dysfunction that affects veterans with GWI. We have previously reported that fingolimod, a drug approved for the treatment of relapsing-remitting multiple sclerosis, decreases neuroinflammation and improves cognition in a mouse model of Alzheimer's disease. In this study, we investigated the effect of fingolimod treatment on cognition and neuroinflammation in a mouse model of GWI. We exposed C57BL/6 J male mice to GWI-related chemicals pyridostigmine bromide, DEET, and permethrin, and to mild restraint stress for 28 days (GWI mice). Control mice were exposed to the chemicals' vehicle only. Starting 3 months post-exposure, half of the GWI mice and control mice were orally treated with fingolimod (1 mg/kg/day) for 1 month, and the other half were left untreated. Decreased memory on the Morris water maze test was detected in GWI mice compared to control mice and was reversed by fingolimod treatment. Immunohistochemical analysis of brain sections with antibodies to Iba1 and GFAP revealed that GWI mice had increased microglia activation in the hippocampal dentate gyrus, but no difference in reactive astrocytes was detected. The increased activation of microglia in GWI mice was decreased to the level in control mice by treatment with fingolimod. No effect of fingolimod treatment on gliosis in control mice was detected. To explore the signaling pathways by which decreased memory and increased neuroinflammation in GWI may be protected by fingolimod, we investigated the involvement of the inflammatory signaling pathways of protein kinase R (PKR) in the cerebral cortex of these mice. We found increased phosphorylation of PKR in the brain of GWI mice compared to controls, as well as increased phosphorylation of its most recognized downstream effectors: the α subunit of eukaryotic initiation factor 2 (eIF2α), IκB kinase (IKK), and the p65 subunit of nuclear factor-κB (NFκB-p65). Furthermore, we found that the increased phosphorylation level of these three proteins were suppressed in GWI mice treated with fingolimod. These results suggest that activation of PKR and NFκB signaling may be important for the regulation of cognition and neuroinflammation in the GWI condition and that fingolimod, a drug already approved for human use, may be a potential candidate for the treatment of GWI.
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Affiliation(s)
- Isabel Carreras
- Department of Veterans Affairs, VA Boston Healthcare System,150 S Huntington Av, Boston, MA 02130, USA; Department of Neurology, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA.
| | - Younghun Jung
- Department of Veterans Affairs, VA Boston Healthcare System,150 S Huntington Av, Boston, MA 02130, USA; Department of Neurology, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118, USA; The Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, 73 High St, Boston, MA 02114, USA
| | - Jonathan Lopez-Benitez
- Department of Veterans Affairs, VA Boston Healthcare System,150 S Huntington Av, Boston, MA 02130, USA; Department of Neurology, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118, USA
| | - Christina M Tognoni
- Department of Veterans Affairs, VA Boston Healthcare System,150 S Huntington Av, Boston, MA 02130, USA; Department of Neurology, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118, USA
| | - Alpaslan Dedeoglu
- Department of Veterans Affairs, VA Boston Healthcare System,150 S Huntington Av, Boston, MA 02130, USA; Department of Neurology, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118, USA; Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 73 High St, Boston, MA 02114, USA
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16
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Clark DN, Begg LR, Filiano AJ. Unique aspects of IFN-γ/STAT1 signaling in neurons. Immunol Rev 2022; 311:187-204. [PMID: 35656941 PMCID: PMC10120860 DOI: 10.1111/imr.13092] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/01/2022] [Accepted: 05/12/2022] [Indexed: 01/05/2023]
Abstract
The IFN-γ/STAT1 immune signaling pathway impacts many homeostatic and pathological aspects of neurons, beyond its canonical role in controlling intracellular pathogens. Well known for its potent pro-inflammatory and anti-viral functions in the periphery, the IFN-γ/STAT1 pathway is rapidly activated then deactivated to prevent excessive inflammation; however, neurons utilize unique IFN-γ/STAT1 activation patterns, which may contribute to the non-canonical neuron-specific downstream effects. Though it is now well-established that the immune system interacts and supports the CNS in health and disease, many aspects regarding IFN-γ production in the CNS and how neurons respond to IFN-γ are unclear. Additionally, it is not well understood how the diversity of the IFN-γ/STAT1 pathway is regulated in neurons to control homeostatic functions, support immune surveillance, and prevent pathologies. In this review, we discuss the neuron-specific mechanisms and kinetics of IFN-γ/STAT1 activation, the potential sources and entry sites of IFN-γ in the CNS, and the diverse set of homeostatic and pathological effects IFN-γ/STAT1 signaling in neurons has on CNS health and disease. We will also highlight the different contexts and conditions under which IFN-γ-induced STAT1 activation has been studied in neurons, and how various factors might contribute to the vast array of downstream effects observed.
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Affiliation(s)
- Danielle N. Clark
- Department of Immunology, Duke University, Durham, North Carolina, USA
- Marcus Center for Cellular Cures, Duke University, Durham, North Carolina, USA
| | - Lauren R. Begg
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Anthony J. Filiano
- Department of Immunology, Duke University, Durham, North Carolina, USA
- Marcus Center for Cellular Cures, Duke University, Durham, North Carolina, USA
- Department of Pathology, Duke University, Durham, North Carolina, USA
- Department of Neurosurgery, Duke University, Durham, North Carolina, USA
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17
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Di Domenico F, Lanzillotta C. The disturbance of protein synthesis/degradation homeostasis is a common trait of age-related neurodegenerative disorders. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 132:49-87. [PMID: 36088079 DOI: 10.1016/bs.apcsb.2022.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Protein homeostasis or "proteostasis" represent the process that regulates the balance of the intracellular functional and "healthy" proteins. Proteostasis is fundamental to preserve physiological metabolic processes in the cell and it allow to respond to any given stimulus as the expression of components of the proteostasis network is customized according to the proteomic demands of different cellular environments. In conditions that promote unfolding/misfolding of proteins chaperones act as signaling molecules inducing extreme measures to either fix the problem or destroy unfolded proteins. When the chaperone machinery fails under pathological insults unfolded proteins induce the endoplasmic reticulum (ER) stress activating the unfolded protein response (UPR) machinery. The activation of the UPR restores ER proteostasis primarily through the transcriptional remodeling of ER protein folding, trafficking, and degradation pathways, such as the ubiquitin proteasome system (UPS). If these mechanisms do not manage to clear the aberrant proteins, proteasome overload and become defective, and misfolded proteins may form aggregates thus extending the UPR mechanism. These aggregates are then attempted to be cleared by macroautophagy. Impaired proteostasis promote the accumulation of misfolded proteins that exacerbate the damage to chaperones, surveillance systems and/or degradative activities. Remarkably, the removal of toxic misfolded proteins is critical for all cells, but it is especially significant in neurons since these cannot be readily replaced. In neurons, the maintenance of efficient proteostasis is essential to healthy aging since the dysregulation of the proteostasis network can lead to neurodegenerative disease. Each of these brain pathologies is characterized by the repeated misfolding of one of more peculiar proteins, which evade both the protein folding machinery and cellular degradation mechanisms and begins to form aggregates that nucleate out into large fibrillar aggregates. In this chapter we describe the mechanisms, associated with faulty proteostasis, that promote the formation of protein aggregates, amyloid fibrils, intracellular, and extracellular inclusions in the most common nondegenerative disorders also referred to as protein misfolding disorders.
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Affiliation(s)
- Fabio Di Domenico
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy.
| | - Chiara Lanzillotta
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
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18
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Oliveira MM, Klann E. eIF2-dependent translation initiation: Memory consolidation and disruption in Alzheimer's disease. Semin Cell Dev Biol 2022; 125:101-109. [PMID: 34304995 PMCID: PMC8782933 DOI: 10.1016/j.semcdb.2021.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/20/2021] [Accepted: 07/12/2021] [Indexed: 01/05/2023]
Abstract
Memory storage is a conserved survivability feature, present in virtually any complex species. During the last few decades, much effort has been devoted to understanding how memories are formed and which molecular switches define whether a memory should be stored for a short or a long period of time. Among these, de novo protein synthesis is known to be required for the conversion of short- to long-term memory. There are a number translational control pathways involved in synaptic plasticity and memory consolidation, including the phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2α), which has emerged as a critical molecular switch for long-term memory consolidation. In this review, we discuss findings pertaining to the requirement of de novo protein synthesis to memory formation, how local dendritic and axonal translation is regulated in neurons, and how these can influence memory consolidation. We also highlight the importance of eIF2α-dependent translation initiation to synaptic plasticity and memory formation. Finally, we contextualize how aberrant phosphorylation of eIF2α contributes to Alzheimer's disease (AD) pathology and how preventing disruption of eIF2-dependent translation may be a therapeutic avenue for preventing and/or restoring memory loss in AD.
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Affiliation(s)
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.
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19
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Inoue R, Nishi H, Osaka M, Yoshida M, Nangaku M. Neutrophil Protein Kinase R Mediates Endothelial Adhesion and Migration by the Promotion of Neutrophil Actin Polymerization. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2173-2183. [PMID: 35396220 DOI: 10.4049/jimmunol.2001349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/20/2022] [Indexed: 06/14/2023]
Abstract
Neutrophils protect against bacterial and fungal infections, but tight regulation of cell activation is essential for avoiding tissue damage in autoimmune disorders. Protein kinase R (PKR) is a serine/threonine kinase originally characterized by its role in the defense mechanisms against viral infection. Although PKR is involved in the signaling pathways of neurodegenerative diseases and metabolic disorders, its function in neutrophils is not well delineated. In this study, we demonstrate that human neutrophil PKR mediates adhesion to endothelial cells under physiological flow conditions but does not mediate rolling on those cells. Also, neutrophil PKR activation contributes to migration toward chemoattractants. Mechanistically, neutrophil PKR mediates the cell spreading and binding to ICAM-1 in static condition. Moreover, Ab microarray reveals that calcium/calmodulin-dependent protein kinase II is phosphorylated downstream of PKR and affects actin polymerization that is a cytoskeleton rearrangement indispensable for neutrophil migration induced by fMLF. In vivo, neutrophil recruitment into the dorsal air pouch of mice is reduced by PKR inhibitor treatment. Also, in mice with nephrotoxic serum nephritis, the compound treatment suppresses neutrophil accumulation in kidney glomerulus and subsequent development of albuminuria. Thus, in vascular inflammation, neutrophil PKR plays a critical role in the recruitment process, including endothelial adhesion and migration via leukocyte actin polymerization.
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Affiliation(s)
- Reiko Inoue
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan; and
| | - Hiroshi Nishi
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan; and
| | - Mizuko Osaka
- Department of Life Science and Bioethics, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masayuki Yoshida
- Department of Life Science and Bioethics, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan; and
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20
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Shiner B, Forehand JA, Rozema L, Kulldorff M, Watts BV, Trefethen M, Jiang T, Huybrechts KF, Schnurr PP, Vincenti M, Gui J, Gradus JL. Mining Clinical Data for Novel Posttraumatic Stress Disorder Medications. Biol Psychiatry 2022; 91:647-657. [PMID: 34952698 PMCID: PMC8918007 DOI: 10.1016/j.biopsych.2021.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/23/2021] [Accepted: 10/12/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Despite the prevalence and negative impact of posttraumatic stress disorder (PTSD), there are few medications approved by the U.S. Food and Drug Administration for treatment, and approved medications do not work well enough. We leveraged large-scale electronic health record data to identify existing medications that may be repurposed as PTSD treatments. METHODS We constructed a mechanistic tree of all Food and Drug Administration-approved medications and used the tree-based scan statistic to identify medications associated with greater than expected levels of clinically meaningful improvement in PTSD symptoms using electronic health record data from the U.S. Department of Veterans Affairs. Our cohort included patients with a diagnosis of PTSD who had repeated symptom measurements using the PTSD Checklist over a 20-year period (N = 168,941). We calculated observed numbers based on patients taking each drug or mechanistically related class of drugs and the expected numbers based on the tree as a whole. RESULTS Medications typically used to treat PTSD, such as the Food and Drug Administration-approved agent sertraline, were associated with improvement in PTSD symptoms, but the effects were small. Several, but not all, direct-acting antivirals used in the treatment of hepatitis C virus demonstrated a strong association with PTSD improvement. The finding was robust to a sensitivity analysis excluding patients who received established PTSD treatments, including trauma-focused psychotherapy, concurrent with hepatitis treatment. CONCLUSIONS Our exploratory approach both demonstrated findings that are consistent with what is known about pharmacotherapy for PTSD and uncovered a novel class of medications that may improve PTSD symptoms.
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Affiliation(s)
- Brian Shiner
- White River Junction Veterans Affairs Medical Center, White River Junction, Vermont; Veterans Administration National Center for PTSD, White River Junction, Vermont; Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
| | | | - Luke Rozema
- Veterans Affairs Medical Center, White River Junction, Vermont
| | - Martin Kulldorff
- Harvard Medical School, Boston, Massachusetts,Brigham and Women’s Hospital, Boston, Massachusetts
| | - Bradley V. Watts
- Veterans Affairs Medical Center, White River Junction, Vermont,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | | | - Tammy Jiang
- Boston University School of Public Health, Boston, Massachusetts
| | - Krista F. Huybrechts
- Harvard Medical School, Boston, Massachusetts,Brigham and Women’s Hospital, Boston, Massachusetts,Boston University School of Public Health, Boston, Massachusetts,Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Paula P. Schnurr
- National Center for Posttraumatic Stress Disorder, White River Junction, Vermont,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Matthew Vincenti
- Veterans Affairs Medical Center, White River Junction, Vermont,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Jiang Gui
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Jaimie L. Gradus
- Boston University School of Public Health, Boston, Massachusetts
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21
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Inhibition of the ISR abrogates mGluR5-dependent long-term depression and spatial memory deficits in a rat model of Alzheimer's disease. Transl Psychiatry 2022; 12:96. [PMID: 35260557 PMCID: PMC8904583 DOI: 10.1038/s41398-022-01862-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 12/13/2022] Open
Abstract
Soluble amyloid-β-protein (Aβ) oligomers, a major hallmark of AD, trigger the integrated stress response (ISR) via multiple pathologies including neuronal hyperactivation, microvascular hypoxia, and neuroinflammation. Increasing eIF2α phosphorylation, the core event of ISR, facilitates metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), and suppressing its phosphorylation has the opposite effect. Having found the facilitation of mGluR5-LTD by Aβ in live rats, we wondered if suppressing eIF2α phosphorylation cascade would protect against the synaptic plasticity and cognitive disrupting effects of Aβ. We demonstrate here that the facilitation of mGluR5-LTD in a delayed rat model by single i.c.v. injection of synthetic Aβ1-42. Systemic administration of the small-molecule inhibitor of the ISR called ISRIB (trans-isomer) prevents Aβ-facilitated LTD and abrogates spatial learning and memory deficits in the hippocampus in exogenous synthetic Aβ-injected rats. Moreover, ex vivo evidence indicates that ISRIB normalizes protein synthesis in the hippocampus. Targeting the ISR by suppressing the eIF2α phosphorylation cascade with the eIF2B activator ISRIB may provide protective effects against the synaptic and cognitive disruptive effects of Aβ which likely mediate the early stage of sporadic AD.
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22
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Janach GMS, Böhm M, Döhne N, Kim HR, Rosário M, Strauss U. Interferon-γ enhances neocortical synaptic inhibition by promoting membrane association and phosphorylation of GABA A receptors in a protein kinase C-dependent manner. Brain Behav Immun 2022; 101:153-164. [PMID: 34998939 DOI: 10.1016/j.bbi.2022.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/11/2021] [Accepted: 01/03/2022] [Indexed: 12/16/2022] Open
Abstract
Interferon-γ (IFN-γ), an important mediator of the antiviral immune response, can also act as a neuromodulator. CNS IFN-γ levels rise acutely in response to infection and therapeutically applied IFN-γ provokes CNS related side effects. Moreover, IFN-γ plays a key role in neurophysiological processes and a variety of chronic neurological and neuropsychiatric conditions. To close the gap between basic research, behavioral implications and clinical applicability, knowledge of the mechanism behind IFN-γ related changes in brain function is crucial. Here, we studied the underlying mechanism of acutely augmented neocortical inhibition by IFN-γ (1.000 IU ml-1) in layer 5 pyramidal neurons of male Wistar rats. We demonstrate postsynaptic mediation of IFN-γ augmented inhibition by pressure application of GABA and analysis of paired pulse ratios. IFN-γ increases membrane presence of GABAAR γ2, as quantified by cell surface biotinylation and functional synaptic GABAAR number, as determined by peak-scaled non-stationary noise analysis. The increase in functional receptor number was comparable to the increase in underlying miniature inhibitory postsynaptic current (mIPSC) amplitudes. Blockage of putative intracellular mediators, namely phosphoinositide 3-kinase and protein kinase C (PKC) by Wortmannin and Calphostin C, respectively, revealed PKC-dependency of the pro-inhibitory IFN-γ effect. This was corroborated by increased serine phosphorylation of P-serine PKC motifs on GABAAR γ2 upon IFN-γ application. GABAAR single channel conductance, intracellular chloride levels and GABAAR driving force are unlikely to contribute to the effect, as shown by single channel recordings and chloride imaging. The effect of IFN-γ on mIPSC amplitudes was similar in female and male rats, suggesting a gender-independent mechanism of action. Collectively, these results indicate a novel mechanism for the regulation of inhibition by IFN-γ, which could impact on neocortical function and therewith behavior.
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Affiliation(s)
- Gabriel M S Janach
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Maximilian Böhm
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Noah Döhne
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Ha-Rang Kim
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, Bordeaux, France
| | - Marta Rosário
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany.
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23
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Machlovi SI, Neuner SM, Hemmer BM, Khan R, Liu Y, Huang M, Zhu JD, Castellano JM, Cai D, Marcora E, Goate AM. APOE4 confers transcriptomic and functional alterations to primary mouse microglia. Neurobiol Dis 2022; 164:105615. [PMID: 35031484 PMCID: PMC8934202 DOI: 10.1016/j.nbd.2022.105615] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 12/09/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Common genetic variants in more than forty loci modulate risk for Alzheimer's disease (AD). AD risk alleles are enriched within enhancers active in myeloid cells, suggesting that microglia, the brain-resident macrophages, may play a key role in the etiology of AD. A major genetic risk factor for AD is Apolipoprotein E (APOE) genotype, with the ε4/ε4 (E4) genotype increasing risk for AD by approximately 15 fold compared to the most common ε3/ε3 (E3) genotype. However, the impact of APOE genotype on microglial function has not been thoroughly investigated. To address this, we cultured primary microglia from mice in which both alleles of the mouse Apoe gene have been humanized to encode either human APOE ε3 or APOE ε4. Relative to E3 microglia, E4 microglia exhibit altered morphology, increased endolysosomal mass, increased cytokine/chemokine production, and increased lipid and lipid droplet accumulation at baseline. These changes were accompanied by decreased translation and increased phosphorylation of eIF2ɑ and eIF2ɑ-kinases that participate in the integrated stress response, suggesting that E4 genotype leads to elevated levels of cellular stress in microglia relative to E3 genotype. Using live-cell imaging and flow cytometry, we also show that E4 microglia exhibited increased phagocytic uptake of myelin and other substrates compared to E3 microglia. While transcriptomic profiling of myelin-challenged microglia revealed a largely overlapping response profile across genotypes, differential enrichment of genes in interferon signaling, extracellular matrix and translation-related pathways was identified in E4 versus E3 microglia both at baseline and following myelin challenge. Together, our results suggest E4 genotype confers several important functional alterations to microglia even prior to myelin challenge, providing insight into the molecular and cellular mechanisms by which APOE4 may increase risk for AD.
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Affiliation(s)
- Saima I Machlovi
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sarah M Neuner
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Brittany M Hemmer
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Riana Khan
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yiyuan Liu
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Min Huang
- James J Peters VA Medical Center, Research & Development, Bronx, NY, USA; Department of Neurology, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jeffrey D Zhu
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joseph M Castellano
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Neurology, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dongming Cai
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; James J Peters VA Medical Center, Research & Development, Bronx, NY, USA; Department of Neurology, New York, NY, USA; Alzheimer Disease Research Center, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Edoardo Marcora
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alison M Goate
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Department of Neurology, New York, NY, USA; Alzheimer Disease Research Center, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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24
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Sidhom E, O’Brien JT, Butcher AJ, Smith HL, Mallucci GR, Underwood BR. Targeting the Unfolded Protein Response as a Disease-Modifying Pathway in Dementia. Int J Mol Sci 2022; 23:2021. [PMID: 35216136 PMCID: PMC8877151 DOI: 10.3390/ijms23042021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 01/27/2023] Open
Abstract
Dementia is a global medical and societal challenge; it has devastating personal, social and economic costs, which will increase rapidly as the world's population ages. Despite this, there are no disease-modifying treatments for dementia; current therapy modestly improves symptoms but does not change the outcome. Therefore, new treatments are urgently needed-particularly any that can slow down the disease's progression. Many of the neurodegenerative diseases that lead to dementia are characterised by common pathological responses to abnormal protein production and misfolding in brain cells, raising the possibility of the broad application of therapeutics that target these common processes. The unfolded protein response (UPR) is one such mechanism. The UPR is a highly conserved cellular stress response to abnormal protein folding and is widely dysregulated in neurodegenerative diseases. In this review, we describe the basic machinery of the UPR, as well as the evidence for its overactivation and pathogenicity in dementia, and for the marked neuroprotective effects of its therapeutic manipulation in murine models of these disorders. We discuss drugs identified as potential UPR-modifying therapeutic agents-in particular the licensed antidepressant trazodone-and we review epidemiological and trial data from their use in human populations. Finally, we explore future directions for investigating the potential benefit of using trazodone or similar UPR-modulating compounds for disease modification in patients with dementia.
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Affiliation(s)
- Emad Sidhom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Windsor Research Unit, Fulbourn Hospital, Cambridge CB21 5EF, UK
- Gnodde Goldman Sachs Translational Neuroscience Unit, Windsor Research Unit, University of Cambridge, Cambridge CB2 1TN, UK
| | - John T. O’Brien
- Department of Psychiatry, University of Cambridge, Herchel Smith Building, Forvie Site, Cambridge CB2 0SZ, UK;
| | - Adrian J. Butcher
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Heather L. Smith
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Giovanna R. Mallucci
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Benjamin R. Underwood
- Cambridgeshire and Peterborough NHS Foundation Trust, Windsor Research Unit, Fulbourn Hospital, Cambridge CB21 5EF, UK
- Gnodde Goldman Sachs Translational Neuroscience Unit, Windsor Research Unit, University of Cambridge, Cambridge CB2 1TN, UK
- Department of Psychiatry, University of Cambridge, Herchel Smith Building, Forvie Site, Cambridge CB2 0SZ, UK;
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25
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Shrestha P, Klann E. Spatiotemporally resolved protein synthesis as a molecular framework for memory consolidation. Trends Neurosci 2022; 45:297-311. [PMID: 35184897 PMCID: PMC8930706 DOI: 10.1016/j.tins.2022.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 01/25/2023]
Abstract
De novo protein synthesis is required for long-term memory consolidation. Dynamic regulation of protein synthesis occurs via a complex interplay of translation factors and modulators. Many components of the protein synthesis machinery have been targeted either pharmacologically or genetically to establish its requirement for memory. The combination of ligand/light-gating and genetic strategies, that is, chemogenetics and optogenetics, has begun to reveal the spatiotemporal resolution of protein synthesis in specific cell types during memory consolidation. This review summarizes current knowledge of the macroscopic and microscopic neural substrates for protein synthesis in memory consolidation. In addition, we highlight future directions for determining the localization and timing of de novo protein synthesis for memory consolidation with tools that permit unprecedented spatiotemporal precision.
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Affiliation(s)
- Prerana Shrestha
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10012, USA; NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
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26
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Korneeva NL. Integrated Stress Response in Neuronal Pathology and in Health. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:S111-S127. [PMID: 35501991 DOI: 10.1134/s0006297922140103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Neurodegeneration involves progressive pathological loss of a specific population of neurons, glial activation, and dysfunction of myelinating oligodendrocytes leading to cognitive impairment and altered movement, breathing, and senses. Neuronal degeneration is a hallmark of aging, stroke, drug abuse, toxic chemical exposure, viral infection, chronic inflammation, and a variety of neurological diseases. Accumulation of intra- and extracellular protein aggregates is a common characteristic of cell pathologies. Excessive production of reactive oxygen species and nitric oxide, induction of endoplasmic reticulum stress, and accumulation of misfolded protein aggregates have been shown to trigger a defensive mechanism called integrated stress response (ISR). Activation of ISR is important for synaptic plasticity in learning and memory formation. However, sustaining of ISR may lead to the development of neuronal pathologies and altered patterns in behavior and perception.
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Affiliation(s)
- Nadejda L Korneeva
- Louisiana State University Health Science Center, Shreveport, LA 71103, USA.
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27
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Krzyzosiak A, Pitera AP, Bertolotti A. An Overview of Methods for Detecting eIF2α Phosphorylation and the Integrated Stress Response. Methods Mol Biol 2022; 2428:3-18. [PMID: 35171470 DOI: 10.1007/978-1-0716-1975-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phosphorylation of the translation initiation factor eIF2α is an adaptive signaling event that is essential for cell and organismal survival from yeast to humans. It is central to the integrated stress response (ISR) that maintains cellular homeostasis in the face of threats ranging from viral infection, amino acid, oxygen, and heme deprivation to the accumulation of misfolded proteins in the endoplasmic reticulum. Phosphorylation of eIF2α has broad physiological, pathological, and therapeutic relevance. However, despite more than two decades of research and growing pharmacological interest, phosphorylation of eIF2α remains difficult to detect and quantify, because of its transient nature and because substoichiometric amounts of this modification are sufficient to profoundly reshape cellular physiology. This review aims to provide a roadmap for facilitating a robust evaluation of eIF2α phosphorylation and its downstream consequences in cells and organisms.
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28
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Abstract
Neuropsychiatric diseases have traditionally been studied from brain, and mind-centric perspectives. However, mounting epidemiological and clinical evidence shows a strong correlation of neuropsychiatric manifestations with immune system activation, suggesting a likely mechanistic interaction between the immune and nervous systems in mediating neuropsychiatric disease. Indeed, immune mediators such as cytokines, antibodies, and complement proteins have been shown to affect various cellular members of the central nervous system in multitudinous ways, such as by modulating neuronal firing rates, inducing cellular apoptosis, or triggering synaptic pruning. These observations have in turn led to the exciting development of clinical therapies aiming to harness this neuro-immune interaction for the treatment of neuropsychiatric disease and symptoms. Besides the clinic, important theoretical fundamentals can be drawn from the immune system and applied to our understanding of the brain and neuropsychiatric disease. These new frameworks could lead to novel insights in the field and further potentiate the development of future therapies to treat neuropsychiatric disease.
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29
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Chen YG, Hur S. Cellular origins of dsRNA, their recognition and consequences. Nat Rev Mol Cell Biol 2021; 23:286-301. [PMID: 34815573 DOI: 10.1038/s41580-021-00430-1] [Citation(s) in RCA: 121] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2021] [Indexed: 01/02/2023]
Abstract
Double-stranded RNA (dsRNA) is associated with most viral infections - it either constitutes the viral genome (in the case of dsRNA viruses) or is generated in host cells during viral replication. Hence, nearly all organisms have the capability of recognizing dsRNA and mounting a response, the primary aim of which is to mitigate the potential infection. In vertebrates, a set of innate immune receptors for dsRNA induce a multitude of cell-intrinsic and cell-extrinsic immune responses upon dsRNA recognition. Notably, recent studies showed that vertebrate cells can accumulate self-derived dsRNAs or dsRNA-like species upon dysregulation of several cellular processes, activating the very same immune pathways as in infected cells. On the one hand, such aberrant immune activation in the absence of infection can lead to pathogenesis of immune disorders, such as Aicardi-Goutières syndrome. On the other hand, the same innate immune reaction can be induced in a controlled setting for a therapeutic benefit, as occurs in immunotherapies. In this Review, we describe mechanisms by which immunostimulatory dsRNAs are generated in mammalian cells, either by viruses or by the host cells, and how cells respond to them, with the focus on recent developments regarding the role of cellular dsRNAs in immune modulation.
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Affiliation(s)
- Y Grace Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Sun Hur
- Harvard Medical School & Boston Children's Hospital, Boston, MA, USA.
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30
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Cell-type-specific disruption of PERK-eIF2α signaling in dopaminergic neurons alters motor and cognitive function. Mol Psychiatry 2021; 26:6427-6450. [PMID: 33879865 PMCID: PMC8526653 DOI: 10.1038/s41380-021-01099-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/20/2021] [Accepted: 04/01/2021] [Indexed: 02/02/2023]
Abstract
Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) has been shown to activate the eIF2α kinase PERK to directly regulate translation initiation. Tight control of PERK-eIF2α signaling has been shown to be necessary for normal long-lasting synaptic plasticity and cognitive function, including memory. In contrast, chronic activation of PERK-eIF2α signaling has been shown to contribute to pathophysiology, including memory impairments, associated with multiple neurological diseases, making this pathway an attractive therapeutic target. Herein, using multiple genetic approaches we show that selective deletion of the PERK in mouse midbrain dopaminergic (DA) neurons results in multiple cognitive and motor phenotypes. Conditional expression of phospho-mutant eIF2α in DA neurons recapitulated the phenotypes caused by deletion of PERK, consistent with a causal role of decreased eIF2α phosphorylation for these phenotypes. In addition, deletion of PERK in DA neurons resulted in altered de novo translation, as well as changes in axonal DA release and uptake in the striatum that mirror the pattern of motor changes observed. Taken together, our findings show that proper regulation of PERK-eIF2α signaling in DA neurons is required for normal cognitive and motor function in a non-pathological state, and also provide new insight concerning the onset of neuropsychiatric disorders that accompany UPR failure.
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31
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Noyes NC, Phan A, Davis RL. Memory suppressor genes: Modulating acquisition, consolidation, and forgetting. Neuron 2021; 109:3211-3227. [PMID: 34450024 PMCID: PMC8542634 DOI: 10.1016/j.neuron.2021.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/15/2021] [Accepted: 07/30/2021] [Indexed: 02/06/2023]
Abstract
The brain has a remarkable but underappreciated capacity to limit memory formation and expression. The term "memory suppressor gene" was coined in 1998 as an attempt to explain emerging reports that some genes appeared to limit memory. At that time, only a handful of memory suppressor genes were known, and they were understood to work by limiting cAMP-dependent consolidation. In the intervening decades, almost 100 memory suppressor genes with diverse functions have been discovered that affect not only consolidation but also acquisition and forgetting. Here we highlight the surprising extent to which biological limits are placed on memory formation through reviewing the literature on memory suppressor genes. In this review, we present memory suppressors within the framework of their actions on different memory operations: acquisition, consolidation, and forgetting. This is followed by a discussion of the reasons why there may be a biological need to limit memory formation.
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Affiliation(s)
- Nathaniel C Noyes
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Anna Phan
- Department of Biological Sciences, University of Alberta, 11355 Saskatchewan Drive, Edmonton, AB T6G 2E9, Canada
| | - Ronald L Davis
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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32
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Posillico CK. Three's Company: Neuroimmune activation, sex, and memory at the tripartite synapse. Brain Behav Immun Health 2021; 16:100326. [PMID: 34589812 PMCID: PMC8474433 DOI: 10.1016/j.bbih.2021.100326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/07/2021] [Accepted: 08/09/2021] [Indexed: 12/30/2022] Open
Abstract
The neuroimmune system is required for normal cognitive functions such as learning and memory in addition to its critical role in detecting and responding to invading pathogens and injury. Understanding the functional convergence of neurons, astrocytes, and microglia at the synapse, particularly in the hippocampus, is key to understanding the nuances of such diverse roles. In the healthy brain, communication between all three cells is important for regulating neuronal activation and synaptic plasticity mechanisms, and during neuroinflammation, the activity and functions of all three cells can produce and be modulated by inflammatory cytokines. An important remaining component to this system is the conclusive evidence of sex differences in hippocampal plasticity mechanisms, hormone modulation of synaptic plasticity, functional properties of hippocampal neurons, and in neuroimmune activation. Sex as a biological variable here is necessary to consider given sex differences in the prevalence of memory-related disorders such as Alzheimer's disease and Post-Traumatic Stress disorder, both of which present with neuroimmune dysregulation. To make meaningful progress towards a deeper understanding of sex biases in memory-related disease prevalence, I propose that the next chapter of psychoneuroimmune research must focus on the signal integration and transduction at the synapse between experience-dependent plasticity mechanisms, neuroimmune activation, and the influence of biological sex.
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33
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Lopez-Grancha M, Bernardelli P, Moindrot N, Genet E, Vincent C, Roudieres V, Krick AI, Sabuco JF, Machnik D, Ibghi D, Pradier L, Taupin V. A Novel Selective PKR Inhibitor Restores Cognitive Deficits and Neurodegeneration in Alzheimer Disease Experimental Models. J Pharmacol Exp Ther 2021; 378:262-275. [PMID: 34531308 DOI: 10.1124/jpet.121.000590] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/09/2021] [Indexed: 11/22/2022] Open
Abstract
In Alzheimer disease (AD), the double-strand RNA-dependent kinase protein kinase R (PKR )/EIF2AK2 is activated in brain with increased phosphorylation of its substrate eukaryotic initiation factor 2α (eIF2α). AD risk-promoting factors, such as ApoE4 allele or the accumulation of neurotoxic amyloid-β oligomers (AβOs), have been associated with activation of PKR-dependent signaling. Here, we report the discovery of a novel potent and selective PKR inhibitor (SAR439883) and demonstrate its neuroprotective pharmacological activity in AD experimental models. In ApoE4 human replacement male mice, 1-week oral treatment with SAR439883 rescued short-term memory impairment in the spatial object recognition test and dose-dependently reduced learning and memory deficits in the Barnes maze test. Moreover, in AβO-injected male mice, a 2-week administration of SAR439883 in diet dose-dependently ameliorated the AβO-induced cognitive impairment in both Y-maze and Morris Water Maze, prevented loss of synaptic proteins, and reduced levels of the proinflammatory cytokine interleukin-1β In both mouse models, these effects were associated with a dose-dependent inhibition of brain PKR activity as measured by both PKR occupancy and partial lowering of peIF2α levels. Our results provide evidence that selective pharmacological inhibition of PKR by a small selective molecule can rescue memory deficits and prevent neurodegeneration in animal models of AD-like pathology, suggesting that inhibition of PKR is a potential therapeutic approach for AD. SIGNIFICANCE STATEMENT: This study reports the identification of a new small molecule potent and selective protein kinase R (PKR) inhibitor that can prevent cognitive deficits and neurodegeneration in Alzheimer disease (AD) experimental models, including a mouse model expressing the most prevalent AD genetic risk factor ApoE4. With high potency and selectivity, this PKR inhibitor represents a unique tool for investigating the physiological role of PKR and a starting point for developing new drug candidates for AD.
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Affiliation(s)
- Matilde Lopez-Grancha
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Patrick Bernardelli
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Nicolas Moindrot
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Elisabeth Genet
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Carine Vincent
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Valerie Roudieres
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - AIain Krick
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Jean-François Sabuco
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - David Machnik
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Delphine Ibghi
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Laurent Pradier
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
| | - Veronique Taupin
- Neurodegeneration Cluster, Rare and Neurologic Disease Research TA (M.L.-G., N.M., E.G., C.V., V.R., D.I., L.P., V.T.), Integrated Drug Discovery (P.B., J.-F.S., D.M.), and DMPK (A.K.), Sanofi R&D, Chilly-Mazarin, France
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English AM, Green KM, Moon SL. A (dis)integrated stress response: Genetic diseases of eIF2α regulators. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1689. [PMID: 34463036 DOI: 10.1002/wrna.1689] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Alyssa M English
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Katelyn M Green
- Department of Chemistry, Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie L Moon
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
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Abstract
Interactions between the immune system and the nervous system have been described mostly in the context of diseases. More recent studies have begun to reveal how certain immune cell-derived soluble effectors, the cytokines, can influence host behaviour even in the absence of infection. In this Review, we contemplate how the immune system shapes nervous system function and how it controls the manifestation of host behaviour. Interactions between these two highly complex systems are discussed here also in the context of evolution, as both may have evolved to maximize an organism's ability to respond to environmental threats in order to survive. We describe how the immune system relays information to the nervous system and how cytokine signalling occurs in neurons. We also speculate on how the brain may be hardwired to receive and process information from the immune system. Finally, we propose a unified theory depicting a co-evolution of the immune system and host behaviour in response to the evolutionary pressure of pathogens.
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36
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Helseth AR, Hernandez-Martinez R, Hall VL, Oliver ML, Turner BD, Caffall ZF, Rittiner JE, Shipman MK, King CS, Gradinaru V, Gerfen C, Costa-Mattioli M, Calakos N. Cholinergic neurons constitutively engage the ISR for dopamine modulation and skill learning in mice. Science 2021; 372:372/6540/eabe1931. [PMID: 33888613 DOI: 10.1126/science.abe1931] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/22/2020] [Accepted: 03/12/2021] [Indexed: 12/25/2022]
Abstract
The integrated stress response (ISR) maintains proteostasis by modulating protein synthesis and is important in synaptic plasticity, learning, and memory. We developed a reporter, SPOTlight, for brainwide imaging of ISR state with cellular resolution. Unexpectedly, we found a class of neurons in mouse brain, striatal cholinergic interneurons (CINs), in which the ISR was activated at steady state. Genetic and pharmacological manipulations revealed that ISR signaling was necessary in CINs for normal type 2 dopamine receptor (D2R) modulation. Inhibiting the ISR inverted the sign of D2R modulation of CIN firing and evoked dopamine release and altered skill learning. Thus, a noncanonical, steady-state mode of ISR activation is found in CINs, revealing a neuromodulatory role for the ISR in learning.
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Affiliation(s)
- Ashley R Helseth
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA.
| | | | - Victoria L Hall
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27715, USA
| | - Matthew L Oliver
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27715, USA
| | - Brandon D Turner
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA
| | - Zachary F Caffall
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA
| | - Joseph E Rittiner
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA
| | - Miranda K Shipman
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA
| | - Connor S King
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA
| | - Viviana Gradinaru
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Charles Gerfen
- Section on Neuroanatomy, National Institute of Mental Health, Bethesda, MD 20892, USA
| | | | - Nicole Calakos
- Department of Neurology, Duke University Medical Center, Durham, NC 27715, USA. .,Department of Neurobiology, Duke University Medical Center, Durham, NC 27715, USA.,Department of Cell Biology, Duke University Medical Center, Durham, NC 27715, USA.,Duke Institute for Brain Sciences, Duke University, Durham, NC 27715, USA
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37
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Atypical electrophysiological and behavioral responses to diazepam in a leading mouse model of Down syndrome. Sci Rep 2021; 11:9521. [PMID: 33947925 PMCID: PMC8096846 DOI: 10.1038/s41598-021-89011-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/15/2021] [Indexed: 02/02/2023] Open
Abstract
Mounting evidence implicates dysfunctional GABAAR-mediated neurotransmission as one of the underlying causes of learning and memory deficits observed in the Ts65Dn mouse model of Down syndrome (DS). The specific origin and nature of such dysfunction is still under investigation, which is an issue with practical consequences to preclinical and clinical research, as well as to the care of individuals with DS and anxiety disorder or those experiencing seizures in emergency room settings. Here, we investigated the effects of GABAAR positive allosteric modulation (PAM) by diazepam on brain activity, synaptic plasticity, and behavior in Ts65Dn mice. We found Ts65Dn mice to be less sensitive to diazepam, as assessed by electroencephalography, long-term potentiation, and elevated plus-maze. Still, diazepam pre-treatment displayed typical effectiveness in reducing susceptibility and severity to picrotoxin-induced seizures in Ts65Dn mice. These findings fill an important gap in the understanding of GABAergic function in a key model of DS.
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38
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Martinez NW, Gómez FE, Matus S. The Potential Role of Protein Kinase R as a Regulator of Age-Related Neurodegeneration. Front Aging Neurosci 2021; 13:638208. [PMID: 33994991 PMCID: PMC8113420 DOI: 10.3389/fnagi.2021.638208] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/10/2021] [Indexed: 01/25/2023] Open
Abstract
There is a growing evidence describing a decline in adaptive homeostasis in aging-related diseases affecting the central nervous system (CNS), many of which are characterized by the appearance of non-native protein aggregates. One signaling pathway that allows cell adaptation is the integrated stress response (ISR), which senses stress stimuli through four kinases. ISR activation promotes translational arrest through the phosphorylation of the eukaryotic translation initiation factor 2 alpha (eIF2α) and the induction of a gene expression program to restore cellular homeostasis. However, depending on the stimulus, ISR can also induce cell death. One of the ISR sensors is the double-stranded RNA-dependent protein kinase [protein kinase R (PKR)], initially described as a viral infection sensor, and now a growing evidence supports a role for PKR on CNS physiology. PKR has been largely involved in the Alzheimer’s disease (AD) pathological process. Here, we reviewed the antecedents supporting the role of PKR on the efficiency of synaptic transmission and cognition. Then, we review PKR’s contribution to AD and discuss the possible participation of PKR as a player in the neurodegenerative process involved in aging-related pathologies affecting the CNS.
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Affiliation(s)
- Nicolás W Martinez
- Fundación Ciencia & Vida, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | | | - Soledad Matus
- Fundación Ciencia & Vida, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
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39
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Hetz C. Adapting the proteostasis capacity to sustain brain healthspan. Cell 2021; 184:1545-1560. [PMID: 33691137 DOI: 10.1016/j.cell.2021.02.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/20/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
Sustaining neuronal proteostasis during the course of our life is a central aspect required for brain function. The dynamic nature of synaptic composition and abundance is a requisite to drive cognitive and motor processes involving a tight control of many aspects of protein biosynthesis and degradation. Through the concerted action of specialized stress sensors, the proteostasis network monitors and limits the accumulation of damaged, misfolded, or aggregated proteins. These stress pathways signal to the cytosol and nucleus to reprogram gene expression, enabling adaptive programs to recover cell function. During aging, the activity of the proteostasis network declines, which may increase the risk of accumulating abnormal protein aggregates, a hallmark of most neurodegenerative diseases. Here, I discuss emerging concepts illustrating the functional significance of adaptive signaling pathways to normal brain physiology and their contribution to age-related disorders. Pharmacological and gene therapy strategies to intervene and boost proteostasis are expected to extend brain healthspan and ameliorate disease states.
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Affiliation(s)
- Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA, USA.
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40
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Lu Y, Yang Y, Peng Z, Xie L, Zhong X, Liang F, Yuan C, Lu B. Silencing IFNγ inhibits A1 astrocytes and attenuates neurogenesis decline and cognitive impairment in endotoxemia. Biochem Biophys Res Commun 2020; 533:1519-1526. [PMID: 33158480 DOI: 10.1016/j.bbrc.2020.10.084] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 10/26/2020] [Indexed: 11/30/2022]
Abstract
Cognitive impairment, acute or long-term, is a common complication in patients with severe bacterial infection. However, the underlying mechanisms are not fully verified and effective medicine is not available in clinics. Interferon gamma (IFNγ) is a pivotal cytokine against infection and is believed to be a tune in homeostasis of cognitive function. Here, we collected blood and cerebrospinal fluid (CF) from human subjects and mice, and found that plasma and CF levels of IFNγ were significantly increased in septic patients and endotoxin-challenged mice when compared with healthy controls. IFNγ signaling was boosted in the hippocampus of mice after a challenge of lipopolysaccharide (LPS), which was accompanied with cognitive impairment and decline of neurogenesis. Deficiency of IFNγ or its receptor (IFNγR) dramatically attenuated microglia-induced A1 astrocytes and consequently restored neurogenesis and cognitive function in endotoxemia mice model. Using primary microglia, astrocytes and neurons, we found that IFNγ remarkably increased LPS-mediated release of TNFα and IL-1α in microglia and consequently induced the transformation of astrocyte to A1 subtype, which ultimately resulted in neuron damage. Thus, IFNγ promotes cognitive impairment in endotoxemia by enhancing microglia-induced A1 astrocytes. Targeting IFNγ would be a novel strategy for preventing or treating cognitive dysfunction in patients with Gram-negative infection.
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Affiliation(s)
- Yanyan Lu
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China
| | - Yanliang Yang
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China
| | - Zhouyangfan Peng
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China
| | - Lingli Xie
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China; Department of Pathophysiology, Hunan University of Chinese Medicine, Changsha, 410000, PR China
| | - Xiaoli Zhong
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China
| | - Fang Liang
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China
| | - Chuang Yuan
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China.
| | - Ben Lu
- Department of Hematology, The 3rd Xiangya Hospital, Central South University, Changsha, 410000, PR China; Department of Pathophysiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, 410000, PR China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, Changsha, Hunan Province, 410000, PR China.
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41
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Shrestha P, Shan Z, Mamcarz M, Ruiz KSA, Zerihoun AT, Juan CY, Herrero-Vidal PM, Pelletier J, Heintz N, Klann E. Amygdala inhibitory neurons as loci for translation in emotional memories. Nature 2020; 586:407-411. [PMID: 33029009 PMCID: PMC7572709 DOI: 10.1038/s41586-020-2793-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/06/2020] [Indexed: 01/09/2023]
Abstract
To survive in a dynamic environment, animals need to identify and appropriately respond to stimuli that signal danger1. Survival also depends on suppressing the threat-response during a stimulus that predicts the absence of threat (safety)2-5. An understanding of the biological substrates of emotional memories during a task in which animals learn to flexibly execute defensive responses to a threat-predictive cue and a safety cue is critical for developing treatments for memory disorders such as post-traumatic stress disorder5. The centrolateral amygdala is an important node in the neuronal circuit that mediates defensive responses6-9, and a key brain area for processing and storing threat memories. Here we applied intersectional chemogenetic strategies to inhibitory neurons in the centrolateral amygdala of mice to block cell-type-specific translation programs that are sensitive to depletion of eukaryotic initiation factor 4E (eIF4E) and phosphorylation of eukaryotic initiation factor 2α (p-eIF2α). We show that de novo translation in somatostatin-expressing inhibitory neurons in the centrolateral amygdala is necessary for the long-term storage of conditioned-threat responses, whereas de novo translation in protein kinase Cδ-expressing inhibitory neurons in the centrolateral amygdala is necessary for the inhibition of a conditioned response to a safety cue. Our results provide insight into the role of de novo protein synthesis in distinct inhibitory neuron populations in the centrolateral amygdala during the consolidation of long-term memories.
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Affiliation(s)
- Prerana Shrestha
- Center for Neural Science, New York University, New York, NY, USA.
| | - Zhe Shan
- Center for Neural Science, New York University, New York, NY, USA
| | - Maggie Mamcarz
- Center for Neural Science, New York University, New York, NY, USA
| | | | - Adam T Zerihoun
- Center for Neural Science, New York University, New York, NY, USA
| | - Chien-Yu Juan
- Center for Neural Science, New York University, New York, NY, USA
| | | | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Nathaniel Heintz
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA.
- NYU Neuroscience Institute, New York University School of Medicine, New York, NY, USA.
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42
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Sharma V, Sood R, Khlaifia A, Eslamizade MJ, Hung TY, Lou D, Asgarihafshejani A, Lalzar M, Kiniry SJ, Stokes MP, Cohen N, Nelson AJ, Abell K, Possemato AP, Gal-Ben-Ari S, Truong VT, Wang P, Yiannakas A, Saffarzadeh F, Cuello AC, Nader K, Kaufman RJ, Costa-Mattioli M, Baranov PV, Quintana A, Sanz E, Khoutorsky A, Lacaille JC, Rosenblum K, Sonenberg N. eIF2α controls memory consolidation via excitatory and somatostatin neurons. Nature 2020; 586:412-416. [PMID: 33029011 PMCID: PMC7874887 DOI: 10.1038/s41586-020-2805-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
An important tenet of learning and memory is the notion of a molecular switch that promotes the formation of long-term memory1-4. The regulation of proteostasis is a critical and rate-limiting step in the consolidation of new memories5-10. One of the most effective and prevalent ways to enhance memory is by regulating the synthesis of proteins controlled by the translation initiation factor eIF211. Phosphorylation of the α-subunit of eIF2 (p-eIF2α), the central component of the integrated stress response (ISR), impairs long-term memory formation in rodents and birds11-13. By contrast, inhibiting the ISR by mutating the eIF2α phosphorylation site, genetically11 and pharmacologically inhibiting the ISR kinases14-17, or mimicking reduced p-eIF2α with the ISR inhibitor ISRIB11, enhances long-term memory in health and disease18. Here we used molecular genetics to dissect the neuronal circuits by which the ISR gates cognitive processing. We found that learning reduces eIF2α phosphorylation in hippocampal excitatory neurons and a subset of hippocampal inhibitory neurons (those that express somatostatin, but not parvalbumin). Moreover, ablation of p-eIF2α in either excitatory or somatostatin-expressing (but not parvalbumin-expressing) inhibitory neurons increased general mRNA translation, bolstered synaptic plasticity and enhanced long-term memory. Thus, eIF2α-dependent mRNA translation controls memory consolidation via autonomous mechanisms in excitatory and somatostatin-expressing inhibitory neurons.
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Affiliation(s)
- Vijendra Sharma
- Department of Biochemistry, McGill University, Montréal, Québec, Canada.
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.
| | - Rapita Sood
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | | | - Mohammad Javad Eslamizade
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
| | - Tzu-Yu Hung
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Danning Lou
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | | | - Maya Lalzar
- Bioinformatics Services Unit, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa, Israel
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Matthew P Stokes
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | - Noah Cohen
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Alissa J Nelson
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | - Kathryn Abell
- Proteomics Division, Cell Signaling Technology, Danvers, MA, 01923, USA
| | | | | | - Vinh T Truong
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Peng Wang
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
| | - Adonis Yiannakas
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Fatemeh Saffarzadeh
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Karim Nader
- Department of Psychology, McGill University, Montréal, Québec, Canada
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA, USA
| | | | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - Albert Quintana
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Neuroscience Institute, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Elisenda Sanz
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Neuroscience Institute, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Arkady Khoutorsky
- Department of Anesthesia, McGill University, Montréal, Québec, Canada
- Faculty of Dentistry, McGill University, Montréal, Québec, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, University of Montréal, Montréal, Québec, Canada
- Centre for Interdisciplinary Research on Brain and Learning, University of Montréal, Montréal, Québec, Canada
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.
- Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel.
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal, Québec, Canada.
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.
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Eiermann N, Haneke K, Sun Z, Stoecklin G, Ruggieri A. Dance with the Devil: Stress Granules and Signaling in Antiviral Responses. Viruses 2020; 12:v12090984. [PMID: 32899736 PMCID: PMC7552005 DOI: 10.3390/v12090984] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.
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Affiliation(s)
- Nina Eiermann
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Zhaozhi Sun
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
- Correspondence:
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Kapur M, Ganguly A, Nagy G, Adamson SI, Chuang JH, Frankel WN, Ackerman SL. Expression of the Neuronal tRNA n-Tr20 Regulates Synaptic Transmission and Seizure Susceptibility. Neuron 2020; 108:193-208.e9. [PMID: 32853550 DOI: 10.1016/j.neuron.2020.07.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/07/2020] [Accepted: 07/19/2020] [Indexed: 12/31/2022]
Abstract
The mammalian genome has hundreds of nuclear-encoded tRNAs, but the contribution of individual tRNA genes to cellular and organismal function remains unknown. Here, we demonstrate that mutations in a neuronally enriched arginine tRNA, n-Tr20, increased seizure threshold and altered synaptic transmission. n-Tr20 expression also modulated seizures caused by an epilepsy-linked mutation in Gabrg2, a gene encoding a GABAA receptor subunit. Loss of n-Tr20 altered translation initiation by activating the integrated stress response and suppressing mTOR signaling, the latter of which may contribute to altered neurotransmission in mutant mice. Deletion of a highly expressed isoleucine tRNA similarly altered these signaling pathways in the brain, suggesting that regulation of translation initiation is a conserved response to tRNA loss. Our data indicate that loss of a single member of a tRNA family results in multiple cellular phenotypes, highlighting the disease-causing potential of tRNA mutations.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Archan Ganguly
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gabor Nagy
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Scott I Adamson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT 06030, USA
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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45
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Metformin inhibits RAN translation through PKR pathway and mitigates disease in C9orf72 ALS/FTD mice. Proc Natl Acad Sci U S A 2020; 117:18591-18599. [PMID: 32690681 PMCID: PMC7414156 DOI: 10.1073/pnas.2005748117] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Repeat-associated non-AUG (RAN) proteins accumulate in patient brains and contribute to a growing number of neurodegenerative diseases. There is an urgent need to understand why expression of these proteins does not require canonical or near-cognate AUG start codons and to develop ways to block RAN protein production. We show several types of repeat-expansion RNAs activate the double-stranded RNA-dependent protein kinase (PKR) pathway and that blocking PKR reduces RAN protein levels in cells. PKR is activated in C9orf72 ALS/FTD human and mouse brains and PKR inhibition using AAV-PKR-K296R or the FDA-approved drug metformin decreases RAN protein levels and improves disease in ALS/FTD mice. Targeting PKR using gene therapy or metformin are promising therapeutic approaches for C9orf72 ALS/FTD and other expansion diseases. Repeat associated non-AUG (RAN) translation is found in a growing number of microsatellite expansion diseases, but the mechanisms remain unclear. We show that RAN translation is highly regulated by the double-stranded RNA-dependent protein kinase (PKR). In cells, structured CAG, CCUG, CAGG, and G4C2 expansion RNAs activate PKR, which leads to increased levels of multiple RAN proteins. Blocking PKR using PKR-K296R, the TAR RNA binding protein or PKR-KO cells, reduces RAN protein levels. p-PKR is elevated in C9orf72 ALS/FTD human and mouse brains, and inhibiting PKR in C9orf72 BAC transgenic mice using AAV-PKR-K296R or the Food and Drug Administration (FDA)-approved drug metformin, decreases RAN proteins, and improves behavior and pathology. In summary, targeting PKR, including by use of metformin, is a promising therapeutic approach for C9orf72 ALS/FTD and other expansion diseases.
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Wiebe S, Nagpal A, Sonenberg N. Dysregulated translational control in brain disorders: from genes to behavior. Curr Opin Genet Dev 2020; 65:34-41. [PMID: 32535350 DOI: 10.1016/j.gde.2020.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/20/2020] [Accepted: 05/03/2020] [Indexed: 12/24/2022]
Abstract
Control of protein synthesis (mRNA translation) is essential for proper brain development and function. Perturbations to the mechanisms governing mRNA translation have repeatedly been shown to constitute a neurodegenerative, neuropsychiatric, and neurodevelopmental disorder risk factor. Developing effective therapeutics for brain disorders will require a better understanding of the molecular mechanisms underlying the control of protein synthesis in brain function. Studies using transgenic animal models have been invaluable towards this end, providing exciting new insights into the genetic basis of brain disorders with hopeful prospects for new and effective treatment options.
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Affiliation(s)
- Shane Wiebe
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada; Goodman Cancer Research Centre, 1160 Pine Avenue West, Montreal, QC H3A 1A3, Canada
| | - Anmol Nagpal
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada; Goodman Cancer Research Centre, 1160 Pine Avenue West, Montreal, QC H3A 1A3, Canada; Integrated Program in Neuroscience, McGill University, Montreal Neurological Institute, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada; Goodman Cancer Research Centre, 1160 Pine Avenue West, Montreal, QC H3A 1A3, Canada.
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47
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Costa-Mattioli M, Walter P. The integrated stress response: From mechanism to disease. Science 2020; 368:368/6489/eaat5314. [PMID: 32327570 DOI: 10.1126/science.aat5314] [Citation(s) in RCA: 643] [Impact Index Per Article: 160.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Protein quality control is essential for the proper function of cells and the organisms that they make up. The resulting loss of proteostasis, the processes by which the health of the cell's proteins is monitored and maintained at homeostasis, is associated with a wide range of age-related human diseases. Here, we highlight how the integrated stress response (ISR), a central signaling network that responds to proteostasis defects by tuning protein synthesis rates, impedes the formation of long-term memory. In addition, we address how dysregulated ISR signaling contributes to the pathogenesis of complex diseases, including cognitive disorders, neurodegeneration, cancer, diabetes, and metabolic disorders. The development of tools through which the ISR can be modulated promises to uncover new avenues to diminish pathologies resulting from it for clinical benefit.
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Affiliation(s)
- Mauro Costa-Mattioli
- Department of Neuroscience, Memory and Brain Research Center, Baylor College of Medicine, Houston, TX, USA.
| | - Peter Walter
- Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA.
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Alvarez-Castelao B, Tom Dieck S, Fusco CM, Donlin-Asp P, Perez JD, Schuman EM. The switch-like expression of heme-regulated kinase 1 mediates neuronal proteostasis following proteasome inhibition. eLife 2020; 9:52714. [PMID: 32329716 PMCID: PMC7224698 DOI: 10.7554/elife.52714] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 04/20/2020] [Indexed: 12/20/2022] Open
Abstract
We examined the feedback between the major protein degradation pathway, the ubiquitin-proteasome system (UPS), and protein synthesis in rat and mouse neurons. When protein degradation was inhibited, we observed a coordinate dramatic reduction in nascent protein synthesis in neuronal cell bodies and dendrites. The mechanism for translation inhibition involved the phosphorylation of eIF2α, surprisingly mediated by eIF2α kinase 1, or heme-regulated kinase inhibitor (HRI). Under basal conditions, neuronal expression of HRI is barely detectable. Following proteasome inhibition, HRI protein levels increase owing to stabilization of HRI and enhanced translation, likely via the increased availability of tRNAs for its rare codons. Once expressed, HRI is constitutively active in neurons because endogenous heme levels are so low; HRI activity results in eIF2α phosphorylation and the resulting inhibition of translation. These data demonstrate a novel role for neuronal HRI that senses and responds to compromised function of the proteasome to restore proteostasis.
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Affiliation(s)
| | | | - Claudia M Fusco
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Paul Donlin-Asp
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Julio D Perez
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
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49
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Therapeutic effects of the PKR inhibitor C16 suppressing tumor proliferation and angiogenesis in hepatocellular carcinoma in vitro and in vivo. Sci Rep 2020; 10:5133. [PMID: 32198380 PMCID: PMC7083831 DOI: 10.1038/s41598-020-61579-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/21/2020] [Indexed: 11/12/2022] Open
Abstract
The therapeutic effects of C16, which is an inhibitor of RNA-dependent protein kinase (PKR), on growth of hepatocellular carcinoma (HCC) cells and tumor progression in vitro and in vivo were evaluated. Huh7 cells, a human HCC cell line, were used. The effects of C16 on cell viability were evaluated with the MTT assay, and real-time RT-PCR was performed. Huh7 cells were grafted into immunodeficient mice, and the in vivo effects of C16 on tumorigenesis were examined. C16 suppressed proliferation of HCC cells in a dose-dependent manner in vitro. Mouse models with xenograft transplantation showed that the inhibitor suppressed the growth of HCC cells in vivo. Moreover, C16 decreased angiogenesis in HCC tissue in the xenograft model. Consistent with these results in mice, transcript levels of vascular endothelial growth factor-A and factor-B, platelet-derived growth factor-A and factor-B, fibroblast growth factor-2, epidermal growth factor, and hepatocyte growth factor, which are angiogenesis-related growth factors, were significantly decreased by C16 in vitro. In conclusion, the PKR inhibitor C16 blocked tumor cell growth and angiogenesis via a decrease in mRNA levels of several growth factors. C16 may be useful in the treatment of HCC.
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50
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Janach GMS, Reetz O, Döhne N, Stadler K, Grosser S, Byvaltcev E, Bräuer AU, Strauss U. Interferon-γ acutely augments inhibition of neocortical layer 5 pyramidal neurons. J Neuroinflammation 2020; 17:69. [PMID: 32087716 PMCID: PMC7035745 DOI: 10.1186/s12974-020-1722-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/20/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Interferon-γ (IFN-γ, a type II IFN) is present in the central nervous system (CNS) under various conditions. Evidence is emerging that, in addition to its immunological role, IFN-γ modulates neuronal morphology, function, and development in several brain regions. Previously, we have shown that raising levels of IFN-β (a type I IFN) lead to increased neuronal excitability of neocortical layer 5 pyramidal neurons. Because of shared non-canonical signaling pathways of both cytokines, we hypothesized a similar neocortical role of acutely applied IFN-γ. METHODS We used semi-quantitative RT-PCR, immunoblotting, and immunohistochemistry to analyze neuronal expression of IFN-γ receptors and performed whole-cell patch-clamp recordings in layer 5 pyramidal neurons to investigate sub- and suprathreshold excitability, properties of hyperpolarization-activated cyclic nucleotide-gated current (Ih), and inhibitory neurotransmission under the influence of acutely applied IFN-γ. RESULTS We show that IFN-γ receptors are present in the membrane of rat's neocortical layer 5 pyramidal neurons. As expected from this and the putative overlap in IFN type I and II alternative signaling pathways, IFN-γ diminished Ih, mirroring the effect of type I IFNs, suggesting a likewise activation of protein kinase C (PKC). In contrast, IFN-γ did neither alter subthreshold nor suprathreshold neuronal excitability, pointing to augmented inhibitory transmission by IFN-γ. Indeed, IFN-γ increased electrically evoked inhibitory postsynaptic currents (IPSCs) on neocortical layer 5 pyramidal neurons. Furthermore, amplitudes of spontaneous IPSCs and miniature IPSCs were elevated by IFN-γ, whereas their frequency remained unchanged. CONCLUSIONS The expression of IFN-γ receptors on layer 5 neocortical pyramidal neurons together with the acute augmentation of inhibition in the neocortex by direct application of IFN-γ highlights an additional interaction between the CNS and immune system. Our results strengthen our understanding of the role of IFN-γ in neocortical neurotransmission and emphasize its impact beyond its immunological properties, particularly in the pathogenesis of neuropsychiatric disorders.
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Affiliation(s)
- Gabriel M S Janach
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany
| | - Olivia Reetz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany
| | - Noah Döhne
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany
| | - Konstantin Stadler
- Industrial Ecology Programme, NTNU - Norwegian University of Science and Technology, Trondheim, Norway
| | - Sabine Grosser
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Integrative Neuroanatomy, Berlin, Germany
| | - Egor Byvaltcev
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany
| | - Anja U Bräuer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany.,Research Group Anatomy, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Cell Biology & Neurobiology, Charitéplatz 1, 10117, Berlin, Germany.
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