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Bruni AC, Bernardi L, Gabelli C. From beta amyloid to altered proteostasis in Alzheimer's disease. Ageing Res Rev 2020; 64:101126. [PMID: 32683041 DOI: 10.1016/j.arr.2020.101126] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/27/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is an age related neurodegenerative disorder causing severe disability and important socio-economic burden, but with no cure available to date. To disentangle this puzzling disease genetic studies represented an important way for the comprehension of pathogenic mechanisms. Abnormal processing and accumulation of amyloid-β peptide (Aβ) has been considered the main cause and trigger factor of the disease. The amyloid cascade theory has fallen into crisis because the failure of several anti-amyloid drugs trials and because of the simple equation AD = abnormal Aβ deposition is not always the case. We now know that multiple neurodegenerative diseases share common pathogenic mechanisms leading to accumulation of misfolded protein species. Genome Wide Association studies (GWAS) led to the identification of large numbers of DNA common variants (SNPs) distributed on different chromosomes and modulating the Alzheimer's risk. GWAS genes fall into several common pathways such as immune system and neuroinflammation, lipid metabolism, synaptic dysfunction and endocytosis, all of them addressing to novel routes for different pathogenic mechanisms. Other hints could be derived from epidemiological and experimental studies showing some lifestyles may have a major role in the pathogenesis of many age-associated diseases by modifying cell metabolism, proteostasis and microglia mediated neuroinflammation.
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Affiliation(s)
- Amalia C Bruni
- Regional Neurogenetic Centre, ASP Catanzaro, Lamezia Terme (CZ), Italy.
| | - Livia Bernardi
- Regional Neurogenetic Centre, ASP Catanzaro, Lamezia Terme (CZ), Italy
| | - Carlo Gabelli
- Regional Brain Aging Centre, Azienda Ospedale Università Di Padova, Padova Italy
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152
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Li J, Zhao R, Jiang Y, Xu Y, Zhao H, Lyu X, Wu T. Bilberry anthocyanins improve neuroinflammation and cognitive dysfunction in APP/PSEN1 mice via the CD33/TREM2/TYROBP signaling pathway in microglia. Food Funct 2020; 11:1572-1584. [PMID: 32003387 DOI: 10.1039/c9fo02103e] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Alzheimer's disease, characterized by neuroinflammation and beta-amyloid protein plaques, is a memory-threatening neurodegenerative disease with no effective treatment. Here, the effect of bilberry anthocyanins (BA) on cognitive functions was evaluated using APP/PSEN1 transgenic Alzheimer's disease model mice and their WT littermates. Our results revealed that BA appreciably improves learning and memory abilities and reverses defects to cognitive functions in APP/PSEN1 mice. Furthermore, BA reverses brain, liver and kidney damage caused by Alzheimer's disease, with no significant changes in oxidative stress and lipid metabolism-related indicators. In addition, BA decreases serum and brain lipopolysaccharide (LPS) levels and increases fecal short-chain fatty acid content. Immunofluorescence and RT-PCR analysis results showed that BA fully activates the microglia and astrocytes, downregulates the expression of inflammatory factors (TNF-α, NF-Kβ, IL-1β, IL-6, COX-2, iNOS and CD33) and chemokine receptor CX3CR1, and upregulates the expression of microglia homeostatic factors (TREM2 and TYROBP) and Toll-like receptors (TLR2 and TLR4). Moreover, western blot analysis revealed that BA significantly upregulates the expression of synaptic and phagocytotic function-related proteins (CD68, synaptophysin and IRF7) in APP/PSEN1 mice. Altogether, we show for the first time that BA consumption reverses Alzheimer's disease-induced cognitive disfunction, decreases hippocampal neuroinflammatory responses, and induces phagocytosis of microglia to beta-amyloid protein plaques by regulating the CD33/TREM2/TYROBP signaling pathway in microglia.
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Affiliation(s)
- Jing Li
- State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin 300457, China.
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153
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Alcalà-Vida R, Awada A, Boutillier AL, Merienne K. Epigenetic mechanisms underlying enhancer modulation of neuronal identity, neuronal activity and neurodegeneration. Neurobiol Dis 2020; 147:105155. [PMID: 33127472 DOI: 10.1016/j.nbd.2020.105155] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 02/08/2023] Open
Abstract
Neurodegenerative diseases, including Huntington's disease (HD) and Alzheimer's disease (AD), are progressive conditions characterized by selective, disease-dependent loss of neuronal regions and/or subpopulations. Neuronal loss is preceded by a long period of neuronal dysfunction, during which glial cells also undergo major changes, including neuroinflammatory response. Those dramatic changes affecting both neuronal and glial cells associate with epigenetic and transcriptional dysregulations, characterized by defined cell-type-specific signatures. Notably, increasing studies support the view that altered regulation of transcriptional enhancers, which are distal regulatory regions of the genome capable of modulating the activity of promoters through chromatin looping, play a critical role in transcriptional dysregulation in HD and AD. We review current knowledge on enhancers in HD and AD, and highlight challenging issues to better decipher the epigenetic code of neurodegenerative diseases.
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Affiliation(s)
- Rafael Alcalà-Vida
- LNCA, University of Strasbourg, France; CNRS UMR 7364, Strasbourg, France
| | - Ali Awada
- LNCA, University of Strasbourg, France; CNRS UMR 7364, Strasbourg, France
| | | | - Karine Merienne
- LNCA, University of Strasbourg, France; CNRS UMR 7364, Strasbourg, France.
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154
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CELF2 regulates the species-specific alternative splicing of TREM2. Sci Rep 2020; 10:17995. [PMID: 33093587 PMCID: PMC7582162 DOI: 10.1038/s41598-020-75057-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 10/12/2020] [Indexed: 11/08/2022] Open
Abstract
Genetic variations of TREM2 have been implicated as a risk factor of Alzheimer’s disease (AD). Recent studies suggest that the loss of TREM2 function compromises microglial responses to the accumulation of amyloid beta. Previously, we found that exon 3 of TREM2 is an alternative exon whose skipping leads to a reduction in full-length TREM2 protein by inducing nonsense-mediated mRNA decay. Here, we aimed to identify factors regulating TREM2 splicing. Using a panel of RNA-binding proteins, we found that exon 3 skipping of TREM2 was promoted by two paralogous proteins, CELF1 and CELF2, which were both linked previously with risk loci of AD. Although the overexpression of both CELF1 and CELF2 enhanced exon 3 skipping, only CELF2 reduced the expression of full-length TREM2 protein. Notably, the TREM2 ortholog in the green monkey, but not in the mouse, showed alternative splicing of exon 3 like human TREM2. Similarly, splicing regulation of exon 3 by CELF1/2 was found to be common to humans and monkeys. Using chimeric minigenes of human and mouse TREM2, we mapped a CELF-responsive sequence within intron 3 of human TREM2. Collectively, our results revealed a novel regulatory factor of TREM2 expression and highlighted a species-dependent difference of its regulation.
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155
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Zhu F, Li C, Chu F, Tian X, Zhu J. Target Dysbiosis of Gut Microbes as a Future Therapeutic Manipulation in Alzheimer's Disease. Front Aging Neurosci 2020; 12:544235. [PMID: 33132894 PMCID: PMC7572848 DOI: 10.3389/fnagi.2020.544235] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is commonly an age-associated dementia with neurodegeneration. The pathogenesis of AD is complex and still remains unclear. The inflammation, amyloid β (Aβ), and neurofibrillary tangles as well misfolded tau protein in the brain may contribute to the occurrence and development of AD. Compared with tau protein, Aβ is less toxic. So far, all efforts made in the treatments of AD with targeting these pathogenic factors were unsuccessful over the past decades. Recently, many studies demonstrated that changes of the intestinal environment and gut microbiota via gut–brain axis pathway can cause neurological disorders, such as AD, which may be involved in the pathogenesis of AD. Thus, remodeling the gut microbiota by various ways to maintain their balance might be a novel therapeutic strategy for AD. In the review article, we analyzed the characteristics of gut microbiota and its dysbiosis in AD and its animal models and investigated the possibility of targeting the gut microbiota in the treatment of the patients with AD in the future.
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Affiliation(s)
- Feiqi Zhu
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Chunrong Li
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Fengna Chu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Xiaoping Tian
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Jie Zhu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
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156
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Knockdown of astrocytic TREM2 in the hippocampus relieves cognitive decline in elderly male mice. Behav Brain Res 2020; 397:112939. [PMID: 32991925 DOI: 10.1016/j.bbr.2020.112939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 08/31/2020] [Accepted: 09/21/2020] [Indexed: 12/21/2022]
Abstract
With the lengthening of the human lifespan, an increasing proportion of the population is subject to age-related cognitive impairments, making it important to investigate ways to confront the effects of aging. Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor that is expressed mainly on the surfaces of microglia. Previous studies have found a significant positive correlation between age and TREM2 levels. An increased concentration of soluble TREM2 in cerebrospinal fluid was also found in Alzheimer's disease (AD) patients. Although TREM2 is more highly expressed in microglia than in astrocytes, little attention has been focused on astrocytic TREM2, and the precise role of astrocytic TREM2 in the aging process remains unknown. In this study, we injected TREM2 shRNA into the hippocampal CA1 region to specifically knock down the expression of this protein in astrocytes. We found that TREM2 shRNA injection can improve learning and memory ability in elderly mice, as demonstrated by improved learning ability and memory performance in the Morris water maze (MWM) test, an increased freezing duration in the contextual fear conditioning test, a higher preference ratio in the novel object recognition (NOR) test and a higher alternation rate in the T-maze test. Knocking down astrocytic TREM2 can also rescue impaired long-term potentiation (LTP) induction in the hippocampal CA1 of elderly mice through a presynaptic mechanism. Our results suggest that decreased astrocytic TREM2 levels have beneficial effects on learning and memory ability in elderly mice, which may provide new insight into the pathological mechanism and potential targets of age-related dementia.
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157
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Luukkainen L, Helisalmi S, Kytövuori L, Ahmasalo R, Solje E, Haapasalo A, Hiltunen M, Remes AM, Krüger J. Mutation Analysis of the Genes Linked to Early Onset Alzheimer's Disease and Frontotemporal Lobar Degeneration. J Alzheimers Dis 2020; 69:775-782. [PMID: 31127772 DOI: 10.3233/jad-181256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A lot of effort has been done to unravel the genetics underlying early-onset Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). However, many familial early-onset dementia (EOD) cases still show an unclear genetic background. The aim of this study was to evaluate the role of the known causative mutations and possible pathogenic variants associated with AD and FTLD in a Finnish EOD cohort. The cohort consisted of 39 patients (mean age at onset 54.8 years, range 39-65) with a positive family history of dementia or an atypical or rapidly progressive course of the disease. None of the patients carried the C9orf72 hexanucleotide repeat expansion. Mutations and variants in APP, PSEN1, PSEN2, MAPT, GRN, VCP, CHMP2B, FUS, TARDBP, TREM2, TMEM106B, UBQLN2, SOD1, PRNP, UBQLN1, and BIN1 were screened by using a targeted next generation sequencing panel. Two previously reported pathogenic mutations (PSEN1 p.His163Arg and MAPT p.Arg406Trp) were identified in the cohort. Both patients had familial dementia with an atypical early onset phenotype. In addition, a heterozygous p.Arg71Trp mutation in PSEN2 with an uncertain pathogenic nature was identified in a patient with neuropathologically confirmed AD. In conclusion, targeted investigation of the known dementia-linked genes is worthwhile in patients with onset age under 55 and a positive family history, as well as in patients with atypical features.
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Affiliation(s)
- Laura Luukkainen
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland.,MRC, Oulu University Hospital, Oulu, Finland
| | - Seppo Helisalmi
- Institute of Clinical Medicine, Neurology, University of Eastern Finland, Kuopio, Finland
| | - Laura Kytövuori
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland.,MRC, Oulu University Hospital, Oulu, Finland
| | - Riitta Ahmasalo
- Department of Neurology, Lapland Central Hospital, Rovaniemi, Finland
| | - Eino Solje
- Institute of Clinical Medicine, Neurology, University of Eastern Finland, Kuopio, Finland.,Neuro Center, Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Anne M Remes
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland.,MRC, Oulu University Hospital, Oulu, Finland
| | - Johanna Krüger
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland.,MRC, Oulu University Hospital, Oulu, Finland
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158
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Omokhua-Uyi AG, Van Staden J. Phytomedicinal relevance of South African Cucurbitaceae species and their safety assessment: A review. JOURNAL OF ETHNOPHARMACOLOGY 2020; 259:112967. [PMID: 32422356 DOI: 10.1016/j.jep.2020.112967] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/30/2020] [Accepted: 05/08/2020] [Indexed: 05/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE South Africa has a very rich flora. Many of these species such as those in the Cucurbitaceae family are exploited as medicines for the treatment of various infections. AIM OF THE REVIEW The aim of the review was to synthesize the existing but scattered literature of some plant species in the Cucurbitaceae family used as sources of medicines in South Africa. MATERIALS AND METHODS A literature survey was carried out on the ethnopharmacology, phytochemistry, pharmacological relevance and safety assessment of the South African Cucurbitaceae used as medicines. RESULTS A total of 11 plants namely; Coccinia rehmannii Cogn., Cucumis africanus L.f., Cucumis anguria L. var. longaculeatus J.H.Kirkbr., Cucumis myriocarpus Naudin subsp. myriocarpus, Cucumis zeyheri Sond., Cucumis metuliferus E. Mey ex Naudin, Kedrostis nana (Lam) Cogn., Lagenaria siceraria (Molina) Standl., Momordica balsamina L., Momordica charantia L., and Momordica foetida Schumach. and Thonn were identified. Various traditional medicinal uses for these plants, from common ailments to life-threatening infections were reported. Biological activities including antidiabetic, antioxidant, antimicrobial, anticancer, anti-inflammatory and hepatoprotective were reported. However, some of the plants have not been investigated for some of the biological activities related to their traditional uses. In addition, most of the studies were carried out using non-standardized extracts. Thus, only a few studies on their bioactive constituents exist. Common compounds identified within the species are hydroxycinnamic and hydroxybenzoic acids such as sinapic, gallic, vanillic and salicylic acids; flavonoids such as naringenin, quercetin, kaempferol and rutin; fatty acids such as linoleic, palmitoleic, myristic and stearic acids; the saponin glycosides, momordicin alkaloids and cucurbitacins. However, most of these compounds have not been tested for biological activities. Cucurbitacins were implicated as a major class of toxic compounds present in the plants resulting in poisoning and death. CONCLUSIONS Adequate knowledge of the traditional use of these plants in medicine and the parts used are very important due to the presence of toxic substances and their wide usage. Proper screening of the safety of these plants and products derived from them calls for urgent attention.
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Affiliation(s)
- Aitebiremen Gift Omokhua-Uyi
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3201, South Africa
| | - Johannes Van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3201, South Africa.
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159
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Kim E, Otgontenger U, Jamsranjav A, Kim SS. Deleterious Alteration of Glia in the Brain of Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21186676. [PMID: 32932623 PMCID: PMC7555758 DOI: 10.3390/ijms21186676] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 02/07/2023] Open
Abstract
The deterioration of neurons in Alzheimer’s disease (AD) arises from genetic, immunologic, and cellular factors inside the cortex. The traditional consensus of the amyloid-beta (Aβ) paradigm as a singular cause of AD has been under revision, with the accumulation of exploding neurobiological evidence. Among the multifaceted casualties of AD, the involvement of glia gains significance for its dynamic contribution to neurons, either in a neuroprotective or neurotoxic fashion. Basically, microglia and astrocytes contribute to neuronal sustainability by releasing neuroprotective cytokines, maintaining an adequate amount of glutamate in the synapse, and pruning excessive synaptic terminals. Such beneficial effects divert to the other detrimental cascade in chronic neuroinflammatory conditions. In this change, there are new discoveries of specific cytokines, microRNAs, and complementary factors. Previously unknown mechanisms of ion channels such as Kv1.3, Kir2.1, and HCN are also elucidated in the activation of microglia. The activation of glia is responsible for the excitotoxicity through the overflow of glutamate transmitter via mGluRs expressed on the membrane, which can lead to synaptic malfunction and engulfment. The communication between microglia and astrocytes is mediated through exosomes as well as cytokines, where numerous pieces of genetic information are transferred in the form of microRNAs. The new findings tell us that the neuronal environment in the AD condition is a far more complicated and dynamically interacting space. The identification of each molecule in the milieu and cellular communication would contribute to a better understanding of AD in the neurobiological perspective, consequently suggesting a possible therapeutic clue.
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Affiliation(s)
| | | | | | - Sang Seong Kim
- Correspondence: ; Tel.: +82-31-400-5812; Fax: +82-31-400-5958
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160
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Vardi A, Ben-Dor S, Cho SM, Kalinke U, Spanier J, Futerman AH. Mice defective in interferon signaling help distinguish between primary and secondary pathological pathways in a mouse model of neuronal forms of Gaucher disease. J Neuroinflammation 2020; 17:265. [PMID: 32892753 PMCID: PMC7487497 DOI: 10.1186/s12974-020-01934-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The type 1 interferon (IFN) response is part of the innate immune response and best known for its role in viral and bacterial infection. However, this pathway is also induced in sterile inflammation such as that which occurs in a number of neurodegenerative diseases, including neuronopathic Gaucher disease (nGD), a lysosomal storage disorder (LSD) caused by mutations in GBA. METHODS Mice were injected with conduritol B-epoxide, an irreversible inhibitor of acid beta-glucosidase, the enzyme defective in nGD. MyTrMaSt null mice, where four adaptors of pathogen recognition receptors (PRRs) are deficient, were used to determine the role of the IFN pathway in nGD pathology. Activation of inflammatory and other pathways was analyzed by a variety of methods including RNAseq. RESULTS Elevation in the expression of PRRs associated with the IFN response was observed in CBE-injected mice. Ablation of upstream pathways leading to IFN production had no therapeutic benefit on the lifespan of nGD mice but attenuated neuroinflammation. Primary and secondary pathological pathways (i.e., those associated or not with mouse survival) were distinguished, and a set of ~210 genes including those related to sphingolipid, cholesterol, and lipoprotein metabolism, along with a number of inflammatory pathways related to chemokines, TNF, TGF, complement, IL6, and damage-associated microglia were classified as primary pathological pathways, along with some lysosomal and neuronal genes. CONCLUSIONS Although IFN signaling is the top elevated pathway in nGD, we demonstrate that this pathway is not related to mouse viability and is consequently defined as a secondary pathology pathway. By elimination, we defined a number of critical pathways that are directly related to brain pathology in nGD, which in addition to its usefulness in understanding pathophysiological mechanisms, may also pave the way for the development of novel therapeutic paradigms by targeting such pathways.
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Affiliation(s)
- Ayelet Vardi
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Shifra Ben-Dor
- Life Sciences Core Facilities, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Soo Min Cho
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel
- Current address: NuriScience Inc., Achasan-ro 320, Seoul, 05053, Republic of Korea
| | - Ulrich Kalinke
- TWINCORE-Centre for Experimental and Clinical Infection Research, Institute for Experimental Infection Research, 30625, Hanover, Germany
| | - Julia Spanier
- TWINCORE-Centre for Experimental and Clinical Infection Research, Institute for Experimental Infection Research, 30625, Hanover, Germany
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel.
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161
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The Role of HDL and HDL Mimetic Peptides as Potential Therapeutics for Alzheimer's Disease. Biomolecules 2020; 10:biom10091276. [PMID: 32899606 PMCID: PMC7563116 DOI: 10.3390/biom10091276] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/25/2020] [Accepted: 08/31/2020] [Indexed: 12/11/2022] Open
Abstract
The role of high-density lipoproteins (HDL) in the cardiovascular system has been extensively studied and the cardioprotective effects of HDL are well established. As HDL particles are formed both in the systemic circulation and in the central nervous system, the role of HDL and its associated apolipoproteins in the brain has attracted much research interest in recent years. Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, for which there currently exists no approved disease modifying treatment. Multiple lines of evidence, including a number of large-scale human clinical studies, have shown a robust connection between HDL levels and AD. Low levels of HDL are associated with increased risk and severity of AD, whereas high levels of HDL are correlated with superior cognitive function. Although the mechanisms underlying the protective effects of HDL in the brain are not fully understood, many of the functions of HDL, including reverse lipid/cholesterol transport, anti-inflammation/immune modulation, anti-oxidation, microvessel endothelial protection, and proteopathy modification, are thought to be critical for its beneficial effects. This review describes the current evidence for the role of HDL in AD and the potential of using small peptides mimicking HDL or its associated apolipoproteins (HDL-mimetic peptides) as therapeutics to treat AD.
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162
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Microglia TREM2: A Potential Role in the Mechanism of Action of Electroacupuncture in an Alzheimer's Disease Animal Model. Neural Plast 2020; 2020:8867547. [PMID: 32952550 PMCID: PMC7487106 DOI: 10.1155/2020/8867547] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/29/2020] [Accepted: 08/18/2020] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most serious public health concerns facing the world. Its characteristic feature is neuroinflammation due to microglial activation. Electroacupuncture is one of the therapies employed to improve the condition of patients with AD, although its mechanism of action is still to be determined. Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglia-specific receptor that is involved in regulating neuroinflammation in AD. In this study, we applied senescence-accelerated mouse-prone 8 mice as the AD animal model, used the Morris water maze, and applied hematoxylin and eosin staining, immunofluorescence double staining, and Western blotting, to explore the effects and potential mechanisms of action of electroacupuncture. In summary, this study suggested that electroacupuncture treatment could improve the learning and memory abilities (p < 0.05) and protect neurons. These effects result from acupuncture could upregulate TREM2 expression in the hippocampus (p < 0.01), which was essential for the anti-inflammatory effects in the AD animal model. However, further studies are needed to conclusively demonstrate the mechanism of action of electroacupuncture in AD.
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163
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Goldfarb S, Fainstein N, Ben-Hur T. Electroconvulsive stimulation attenuates chronic neuroinflammation. JCI Insight 2020; 5:137028. [PMID: 32780728 PMCID: PMC7526446 DOI: 10.1172/jci.insight.137028] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 07/29/2020] [Indexed: 12/11/2022] Open
Abstract
Electroconvulsive therapy is highly effective in resistant depression by unknown mechanisms. Microglial toxicity was suggested to mediate depression and plays key roles in neuroinflammatory and degenerative diseases, where there is critical shortage in therapies. We examined the effects of electroconvulsive seizures (ECS) on chronic neuroinflammation and microglial neurotoxicity. Electric brain stimulation inducing full tonic-clonic seizures during chronic relapsing-progressive experimental autoimmune encephalomyelitis (EAE) reduced spinal immune cell infiltration, reduced myelin and axonal loss, and prevented clinical deterioration. Using the transfer EAE model, we examined the effect of ECS on systemic immune response in donor mice versus ECS effect on CNS innate immune activity in recipient mice. ECS did not affect encephalitogenicity of systemic T cells, but it targeted the CNS directly to inhibit T cell-induced neuroinflammation. In vivo and ex vivo assays indicated that ECS suppressed microglial neurotoxicity by reducing inducible NOS expression, nitric oxide, and reactive oxygen species (ROS) production, and by reducing CNS oxidative stress. Microglia from ECS-treated EAE mice expressed less T cell stimulatory and chemoattractant factors. Our findings indicate that electroconvulsive therapy targets the CNS innate immune system to reduce neuroinflammation by attenuating microglial neurotoxicity. These findings signify a potentially novel therapeutic approach for chronic neuroinflammatory, neuropsychiatric, and neurodegenerative diseases.
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164
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de Almeida MMA, Pieropan F, de Mattos Oliveira L, Dos Santos Junior MC, David JM, David JP, da Silva VDA, Dos Santos Souza C, Costa SL, Butt AM. The flavonoid agathisflavone modulates the microglial neuroinflammatory response and enhances remyelination. Pharmacol Res 2020; 159:104997. [PMID: 32534098 PMCID: PMC7482432 DOI: 10.1016/j.phrs.2020.104997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/27/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022]
Abstract
Myelin loss is the hallmark of the demyelinating disease multiple sclerosis (MS) and plays a significant role in multiple neurodegenerative diseases. A common factor in all neuropathologies is the central role of microglia, the intrinsic immune cells of the central nervous system (CNS). Microglia are activated in pathology and can have both pro- and anti-inflammatory functions. Here, we examined the effects of the flavonoid agathisflavone on microglia and remyelination in the cerebellar slice model following lysolecithin induced demyelination. Notably, agathisflavone enhances remyelination and alters microglial activation state, as determined by their morphology and cytokine profile. Furthermore, these effects of agathisflavone on remyelination and microglial activation were inhibited by blockade of estrogen receptor α. Thus, our results identify agathisflavone as a novel compound that may act via ER to regulate microglial activation and enhance remyelination and repair.
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Affiliation(s)
- Monique Marylin Alves de Almeida
- Department of Biochemistry and Biophysics, Institute of Health Sciences, Federal University of Bahia, Brazil; School of Pharmacy and Biomedical Sciences, University of Portsmouth, United Kingdom
| | - Francesca Pieropan
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, United Kingdom
| | | | | | - Jorge Mauricio David
- Department of General and Inorganic Chemistry, Institute of Chemistry, Federal University of Bahia, Brazil
| | - Juceni Pereira David
- Department of Medication, Faculty of Pharmacy, Federal University of Bahia, Brazil
| | - Victor Diógenes A da Silva
- Department of Biochemistry and Biophysics, Institute of Health Sciences, Federal University of Bahia, Brazil
| | - Cleide Dos Santos Souza
- Department of Biochemistry and Biophysics, Institute of Health Sciences, Federal University of Bahia, Brazil; Sheffield Institute for Translational Neuroscience, University of Sheffield, United Kingdom
| | - Silvia Lima Costa
- Department of Biochemistry and Biophysics, Institute of Health Sciences, Federal University of Bahia, Brazil.
| | - Arthur Morgan Butt
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, United Kingdom.
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165
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Flores-Dorantes MT, Díaz-López YE, Gutiérrez-Aguilar R. Environment and Gene Association With Obesity and Their Impact on Neurodegenerative and Neurodevelopmental Diseases. Front Neurosci 2020; 14:863. [PMID: 32982666 PMCID: PMC7483585 DOI: 10.3389/fnins.2020.00863] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Obesity is a multifactorial disease in which environmental conditions and several genes play an important role in the development of this disease. Obesity is associated with neurodegenerative diseases (Alzheimer, Parkinson, and Huntington diseases) and with neurodevelopmental diseases (autism disorder, schizophrenia, and fragile X syndrome). Some of the environmental conditions that lead to obesity are physical activity, alcohol consumption, socioeconomic status, parent feeding behavior, and diet. Interestingly, some of these environmental conditions are shared with neurodegenerative and neurodevelopmental diseases. Obesity impairs neurodevelopment abilities as memory and fine-motor skills. Moreover, maternal obesity affects the cognitive function and mental health of the offspring. The common biological mechanisms involved in obesity and neurodegenerative/neurodevelopmental diseases are insulin resistance, pro-inflammatory cytokines, and oxidative damage, among others, leading to impaired brain development or cell death. Obesogenic environmental conditions are not the only factors that influence neurodegenerative and neurodevelopmental diseases. In fact, several genes implicated in the leptin-melanocortin pathway (LEP, LEPR, POMC, BDNF, MC4R, PCSK1, SIM1, BDNF, TrkB, etc.) are associated with obesity and neurodegenerative and neurodevelopmental diseases. Moreover, in the last decades, the discovery of new genes associated with obesity (FTO, NRXN3, NPC1, NEGR1, MTCH2, GNPDA2, among others) and with neurodegenerative or neurodevelopmental diseases (APOE, CD38, SIRT1, TNFα, PAI-1, TREM2, SYT4, FMR1, TET3, among others) had opened new pathways to comprehend the common mechanisms involved in these diseases. In conclusion, the obesogenic environmental conditions, the genes, and the interaction gene-environment would lead to a better understanding of the etiology of these diseases.
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Affiliation(s)
- María Teresa Flores-Dorantes
- Laboratorio de Biología Molecular y Farmacogenómica, Centro de Investigación de Ciencia y Tecnología Aplicada de Tabasco, División Académica de Ciencias Básicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Mexico
| | - Yael Efren Díaz-López
- Laboratorio de Enfermedades Metabólicas: Obesidad y Diabetes, Hospital Infantil de México “Federico Gómez,”Mexico City, Mexico
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Ruth Gutiérrez-Aguilar
- Laboratorio de Enfermedades Metabólicas: Obesidad y Diabetes, Hospital Infantil de México “Federico Gómez,”Mexico City, Mexico
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
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166
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Brain Glymphatic/Lymphatic Imaging by MRI and PET. Nucl Med Mol Imaging 2020; 54:207-223. [PMID: 33088350 DOI: 10.1007/s13139-020-00665-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/09/2020] [Accepted: 08/19/2020] [Indexed: 01/19/2023] Open
Abstract
Since glymphatic was proposed and meningeal lymphatic was discovered, MRI and even PET were introduced to investigate brain parenchymal interstitial fluid (ISF), cerebrospinal fluid (CSF), and lymphatic outflow in rodents and humans. Previous findings by ex vivo fluorescent microscopic, and in vivo two-photon imaging in rodents were reproduced using intrathecal contrast (gadobutrol and the similar)-enhanced MRI in rodents and further in humans. On dynamic MRI of meningeal lymphatics, in contrast to rodents, humans use mainly dorsal meningeal lymphatic pathways of ISF-CSF-lymphatic efflux. In mice, ISF-CSF exchange was examined thoroughly using an intra-cistern injection of fluorescent tracers during sleep, aging, and neurodegeneration yielding many details. CSF to lymphatic efflux is across arachnoid barrier cells over the dorsal dura in rodents and in humans. Meningeal lymphatic efflux to cervical lymph nodes and systemic circulation is also well-delineated especially in humans onintrathecal contrast MRI. Sleep- or anesthesia-related changes of glymphatic-lymphatic flow and the coupling of ISF-CSF-lymphatic drainage are major confounders ininterpreting brain glymphatic/lymphatic outflow in rodents. PET imaging in humans should be interpreted based on human anatomy and physiology, different in some aspects, using MRI recently. Based on the summary in this review, we propose non-invasive and longer-term intrathecal SPECT/PET or MRI studies to unravel the roles of brain glymphatic/lymphatic in diseases.
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167
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Advani D, Gupta R, Tripathi R, Sharma S, Ambasta RK, Kumar P. Protective role of anticancer drugs in neurodegenerative disorders: A drug repurposing approach. Neurochem Int 2020; 140:104841. [PMID: 32853752 DOI: 10.1016/j.neuint.2020.104841] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/24/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022]
Abstract
The disease heterogeneity and little therapeutic progress in neurodegenerative diseases justify the need for novel and effective drug discovery approaches. Drug repurposing is an emerging approach that reinvigorates the classical drug discovery method by divulging new therapeutic uses of existing drugs. The common biological background and inverse tuning between cancer and neurodegeneration give weight to the conceptualization of repurposing of anticancer drugs as novel therapeutics. Many studies are available in the literature, which highlights the success story of anticancer drugs as repurposed therapeutics. Among them, kinase inhibitors, developed for various oncology indications evinced notable neuroprotective effects in neurodegenerative diseases. In this review, we shed light on the salient role of multiple protein kinases in neurodegenerative disorders. We also proposed a feasible explanation of the action of kinase inhibitors in neurodegenerative disorders with more attention towards neurodegenerative disorders. The problem of neurotoxicity associated with some anticancer drugs is also highlighted. Our review encourages further research to better encode the hidden potential of anticancer drugs with the aim of developing prospective repurposed drugs with no toxicity for neurodegenerative disorders.
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Affiliation(s)
- Dia Advani
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rohan Gupta
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rahul Tripathi
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Sudhanshu Sharma
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rashmi K Ambasta
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Pravir Kumar
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India.
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168
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Koller EJ, Chakrabarty P. Tau-Mediated Dysregulation of Neuroplasticity and Glial Plasticity. Front Mol Neurosci 2020; 13:151. [PMID: 32973446 PMCID: PMC7472665 DOI: 10.3389/fnmol.2020.00151] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/20/2020] [Indexed: 01/14/2023] Open
Abstract
The inability of individual neurons to compensate for aging-related damage leads to a gradual loss of functional plasticity in the brain accompanied by progressive impairment in learning and memory. Whereas this loss in neuroplasticity is gradual during normal aging, in neurodegenerative diseases such as Alzheimer’s disease (AD), this loss is accelerated dramatically, leading to the incapacitation of patients within a decade of onset of cognitive symptoms. The mechanisms that underlie this accelerated loss of neuroplasticity in AD are still not completely understood. While the progressively increasing proteinopathy burden, such as amyloid β (Aβ) plaques and tau tangles, definitely contribute directly to a neuron’s functional demise, the role of non-neuronal cells in controlling neuroplasticity is slowly being recognized as another major factor. These non-neuronal cells include astrocytes, microglia, and oligodendrocytes, which through regulating brain homeostasis, structural stability, and trophic support, play a key role in maintaining normal functioning and resilience of the neuronal network. It is believed that chronic signaling from these cells affects the homeostatic network of neuronal and non-neuronal cells to an extent to destabilize this harmonious milieu in neurodegenerative diseases like AD. Here, we will examine the experimental evidence regarding the direct and indirect pathways through which astrocytes and microglia can alter brain plasticity in AD, specifically as they relate to the development and progression of tauopathy. In this review article, we describe the concepts of neuroplasticity and glial plasticity in healthy aging, delineate possible mechanisms underlying tau-induced plasticity dysfunction, and discuss current clinical trials as well as future disease-modifying approaches.
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Affiliation(s)
- Emily J Koller
- Department of Neuroscience, University of Florida, Gainesville, FL, United States.,Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States
| | - Paramita Chakrabarty
- Department of Neuroscience, University of Florida, Gainesville, FL, United States.,Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,McKnight Brain Institute, University of Florida, Gainesville, FL, United States
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169
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Price BR, Sudduth TL, Weekman EM, Johnson S, Hawthorne D, Woolums A, Wilcock DM. Therapeutic Trem2 activation ameliorates amyloid-beta deposition and improves cognition in the 5XFAD model of amyloid deposition. J Neuroinflammation 2020; 17:238. [PMID: 32795308 PMCID: PMC7427742 DOI: 10.1186/s12974-020-01915-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/30/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Triggering receptor expressed on myeloid cell-2 (TREM2) is a lipid and lipoprotein binding receptor expressed by cells of myeloid origin. Homozygous TREM2 mutations cause early onset progressive presenile dementia while heterozygous, point mutations triple the risk of Alzheimer's disease (AD). Although human genetic findings support the notion that loss of TREM2 function exacerbates neurodegeneration, it is not clear whether activation of TREM2 in a disease state would result in therapeutic benefits. To determine the viability of TREM2 activation as a therapeutic strategy, we sought to characterize an agonistic Trem2 antibody (AL002a) and test its efficacy and mechanism of action in an aggressive mouse model of amyloid deposition. METHODS To determine whether agonism of Trem2 results in therapeutic benefits, we designed both intracranial and systemic administration studies. 5XFAD mice in the intracranial administration study were assigned to one of two injection groups: AL002a, a Trem2-agonizing antibody, or MOPC, an isotype-matched control antibody. Mice were then subject to a single bilateral intracranial injection into the frontal cortex and hippocampus and euthanized 72 h later. The tissue from the left hemisphere was histologically examined for amyloid-beta and microglia activation, whereas the tissue from the right hemisphere was used for biochemical analyses. Similarly, mice in the systemic administration study were randomized to one of the aforementioned injection groups and the assigned antibody was administered intraperitoneally once a week for 14 weeks. Mice underwent behavioral assessment between the 12- and 14-week timepoints and were euthanized 24 h after their final injection. The tissue from the left hemisphere was used for histological analyses whereas the tissue from the right hemisphere was used for biochemical analyses. RESULTS Here, we show that chronic activation of Trem2, in the 5XFAD mouse model of amyloid deposition, leads to reversal of the amyloid-associated gene expression signature, recruitment of microglia to plaques, decreased amyloid deposition, and improvement in spatial learning and novel object recognition memory. CONCLUSIONS These findings indicate that Trem2 activators may be effective for the treatment of AD and possibly other neurodegenerative disorders.
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Affiliation(s)
- Brittani R Price
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - Tiffany L Sudduth
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
| | - Erica M Weekman
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - Sherika Johnson
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
| | - Danielle Hawthorne
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
| | - Abigail Woolums
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - Donna M Wilcock
- Sanders-Brown Center on Aging, College of Medicine, University of Kentucky, 800 S Limestone St, Lexington, KY, 40536, USA.
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA.
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170
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Knight AC, Brill SA, Solis CV, Richardson MR, McCarron ME, Queen SE, Bailey CC, Mankowski JL. Differential regulation of TREM2 and CSF1R in CNS macrophages in an SIV/macaque model of HIV CNS disease. J Neurovirol 2020; 26:511-519. [PMID: 32488843 PMCID: PMC7442592 DOI: 10.1007/s13365-020-00844-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/11/2020] [Accepted: 04/13/2020] [Indexed: 11/26/2022]
Abstract
HIV-associated neuroinflammation is primarily driven by CNS macrophages including microglia. Regulation of these immune responses, however, remains to be characterized in detail. Using the SIV/macaque model of HIV, we evaluated CNS expression of triggering receptor expressed on myeloid cells 2 (TREM2) which is constitutively expressed by microglia and contributes to cell survival, proliferation, and differentiation. Loss-of-function mutations in TREM2 are recognized risk factors for neurodegenerative diseases including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Nasu-Hakola disease (NHD); recent reports have also indicated a role for TREM2 in HIV-associated neuroinflammation. Using in situ hybridization (ISH) and qRT-PCR, TREM2 mRNA levels were found to be significantly elevated in frontal cortex of macaques with SIV encephalitis compared with uninfected controls (P = 0.02). TREM2 protein levels were also elevated as measured by ELISA of frontal cortex tissue homogenates in these animals. Previously, we characterized the expression of CSF1R (colony-stimulating factor 1 receptor) in this model; the TREM2 and CSF1R promoters both contain a PU.1 binding site. While TREM2 and CSF1R mRNA levels in the frontal cortex were highly correlated (Spearman R = 0.79, P < 0.001), protein levels were not well correlated. In SIV-infected macaques released from ART to study viral rebound, neither TREM2 nor CSF1R mRNA increased with rebound viremia. However, CSF1R protein levels remained significantly elevated unlike TREM2 (P = 0.02). This differential expression suggests that TREM2 and CSF1R play unique, distinct roles in the pathogenesis of HIV CNS disease.
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MESH Headings
- Animals
- Antiretroviral Therapy, Highly Active/methods
- Antiviral Agents/pharmacology
- Drug Administration Schedule
- Encephalitis, Viral/drug therapy
- Encephalitis, Viral/genetics
- Encephalitis, Viral/immunology
- Encephalitis, Viral/virology
- Frontal Lobe/drug effects
- Frontal Lobe/immunology
- Frontal Lobe/virology
- Gene Expression Regulation
- Host-Pathogen Interactions/genetics
- Host-Pathogen Interactions/immunology
- Macaca nemestrina/genetics
- Macaca nemestrina/immunology
- Macaca nemestrina/virology
- Macrophages/drug effects
- Macrophages/immunology
- Macrophages/virology
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Microglia/drug effects
- Microglia/immunology
- Microglia/virology
- Promoter Regions, Genetic
- Protein Binding
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/immunology
- RNA, Messenger/genetics
- RNA, Messenger/immunology
- Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/genetics
- Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/immunology
- Simian Acquired Immunodeficiency Syndrome/drug therapy
- Simian Acquired Immunodeficiency Syndrome/genetics
- Simian Acquired Immunodeficiency Syndrome/immunology
- Simian Acquired Immunodeficiency Syndrome/virology
- Simian Immunodeficiency Virus/drug effects
- Simian Immunodeficiency Virus/growth & development
- Simian Immunodeficiency Virus/immunology
- Trans-Activators/genetics
- Trans-Activators/immunology
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Affiliation(s)
- Audrey C Knight
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Samuel A Brill
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Clarisse V Solis
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Morgan R Richardson
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Megan E McCarron
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Suzanne E Queen
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Charles C Bailey
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Emmune, Inc., 130 Scripps Way, Jupiter, Florida, USA
| | - Joseph L Mankowski
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.
- Department of Neurology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.
- Department of Pathology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.
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171
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Guan YF, Huang GB, Xu MD, Gao F, Lin S, Huang J, Wang J, Li YQ, Wu CH, Yao S, Wang Y, Zhang YL, Teoh JP, Xuan A, Sun XD. Anti-depression effects of ketogenic diet are mediated via the restoration of microglial activation and neuronal excitability in the lateral habenula. Brain Behav Immun 2020; 88:748-762. [PMID: 32413556 DOI: 10.1016/j.bbi.2020.05.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/03/2020] [Accepted: 05/09/2020] [Indexed: 12/14/2022] Open
Abstract
Depression is a severe neuropsychiatric disorder, of which the underlying pathological mechanisms remain unclear. The ketogenic diet (KD) has been reported to exhibit preventative effects on depressive-like behaviors in rodents. However, the therapeutic effects of KD on depressive-like behaviors have not been illustrated thus far. Here, we found that KD treatment dramatically ameliorated depressive-like behaviors in both repeated social defeat stress (R-SDS) and lipopolysaccharide (LPS) models, indicating the potential therapeutic effects of KD on depression. Our electrophysiological studies further showed that neuronal excitability was increased in the lateral habenula (LHb) of mice exposed to R-SDS or LPS, which can be reversed in the presence of KD treatment. Moreover, R-SDS and LPS were also found to induce robust microglial inflammatory activation in the LHb. Importantly, these phenotypes were rescued in mice fed with KD. In addition, we found that the protein level of innate immune receptor Trem2 in the LHb was significantly decreased in depression models. Specific knockdown of Trem2 in LHb microglia induced depressive-like behaviors, increased neuronal excitability as well as robust microglial inflammatory activation. Altogether, we demonstrated the therapeutic effects of KD on depressive-like behaviors, which are probably mediated via the restoration of microglial inflammatory activation and neuronal excitability. Besides, we also proposed an unrecognized function of Trem2 in the LHb for depression. Our study sheds light on the pathogenesis of depression and thereby offers a potential therapeutic intervention.
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Affiliation(s)
- Yan-Fei Guan
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Guo-Bin Huang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Min-Dong Xu
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Feng Gao
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Song Lin
- Department of Physiology, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Jie Huang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Jin Wang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yuan-Quan Li
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Cui-Hong Wu
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Shan Yao
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Ying Wang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yun-Long Zhang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Jian-Peng Teoh
- Department of Gynecology and Obstetrics, the Sixth Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Aiguo Xuan
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China.
| | - Xiang-Dong Sun
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China; Guangdong Province Key Laboratory of Psychiatric Disorders, Southern Medical University, Guangzhou 510515, China.
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172
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Ashford BA, Boche D, Cooper-Knock J, Heath PR, Simpson JE, Highley JR. Review: Microglia in motor neuron disease. Neuropathol Appl Neurobiol 2020; 47:179-197. [PMID: 32594542 DOI: 10.1111/nan.12640] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/14/2020] [Indexed: 02/06/2023]
Abstract
Motor Neuron Disease (MND) is a fatal neurodegenerative condition, which is characterized by the selective loss of the upper and lower motor neurons. At the sites of motor neuron injury, accumulation of activated microglia, the primary immune cells of the central nervous system, is commonly observed in both human post mortem studies and animal models of MND. Microglial activation has been found to correlate with many clinical features and importantly, the speed of disease progression in humans. Both anti-inflammatory and pro-inflammatory microglial responses have been shown to influence disease progression in humans and models of MND. As such, microglia could both contribute to and protect against inflammatory mechanisms of pathogenesis in MND. While murine models have characterized the microglial response to MND, these studies have painted a complex and often contradictory picture, indicating a need for further characterization in humans. This review examines the potential role microglia play in MND in human and animal studies. Both the pro-inflammatory and anti-inflammatory responses will be addressed, throughout the course of disease, followed by the potential of microglia as a target in the development of disease-modifying treatments for MND.
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Affiliation(s)
| | - D Boche
- University of Southampton, Southampton, UK
| | | | - P R Heath
- University of Sheffield, Sheffield, UK
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173
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Yang J, Fu Z, Zhang X, Xiong M, Meng L, Zhang Z. TREM2 ectodomain and its soluble form in Alzheimer's disease. J Neuroinflammation 2020; 17:204. [PMID: 32635934 PMCID: PMC7341574 DOI: 10.1186/s12974-020-01878-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a receptor mainly expressed on the surface of microglia. It mediates multiple pathophysiological processes in various diseases. Recently, TREM2 has been found to play a role in the development of Alzheimer's disease (AD). TREM2 is a transmembrane protein that is specifically expressed on microglia in the brain. It contains a long ectodomain that directly interacts with the extracellular environment to regulate microglial function. The ectodomain of TREM2 is processed by a disintegrin and metalloprotease, resulting in the release of a soluble form of TREM2 (sTREM2). Recent studies have demonstrated that sTREM2 is a bioactive molecule capable of binding ligands, activating microglia, and regulating immune responses during the AD continuum. Clinical studies revealed that sTREM2 level is elevated in cerebrospinal fluid (CSF) of AD patients, and the sTREM2 level is positively correlated with the levels of classical CSF biomarkers, namely t-tau and p-tau, indicating that it is a reliable predictor of the early stages of AD. Herein, we summarize the key results on the generation, structure, and function of sTREM2 to provide new insights into TREM2-related mechanisms underlying AD pathogenesis and to promote the development of TREM2-based therapeutic strategy.
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Affiliation(s)
- Jiaolong Yang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhihui Fu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Xingyu Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Min Xiong
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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174
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IL-4 and IL-10 promotes phagocytic activity of microglia by up-regulation of TREM2. Cytotechnology 2020; 72:589-602. [PMID: 32623621 DOI: 10.1007/s10616-020-00409-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 06/26/2020] [Indexed: 02/06/2023] Open
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM2) is an innate immune receptor that promotes phagocytosis by microglia. However, whether TREM2 is related to the stimulus-dependent phagocytic activity of microglia is unclear. In this study, the primary cultured microglia were stimulated with interferon (IFN)-γ, interleukin (IL)-4, and interleukin (IL)-10, respectively, and their phagocytic activity against microbeads and apoptotic neural stem cells (NSCs) was measured. TREM2 of microglia was detected by qPCR and western blotting. The TREM2 signal was blocked in microglia using the siRNA technique. The results showed that IL-4 or IL-10 treatment significantly increased the number of microglia gathered around the apoptotic neurosphere. IL-4 and IL-10 treatment also promoted phagocytosis of microbeads and apoptotic NSCs by primary cultured microglia. The TREM2 expression was up-regulated in IL-4- or IL-10- treated microglia. TREM2 siRNA treatment blocked the phagocytic activity of IL-4- or IL-10-treated microglia. In conclusion, these results indicated that IL-4 and IL-10 promote the phagocytic activity of microglia by the up-regulation of TREM2, which suggested a new potential therapeutic target for neurodegenerative disease.
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175
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Gray SC, Kinghorn KJ, Woodling NS. Shifting equilibriums in Alzheimer's disease: the complex roles of microglia in neuroinflammation, neuronal survival and neurogenesis. Neural Regen Res 2020; 15:1208-1219. [PMID: 31960800 PMCID: PMC7047786 DOI: 10.4103/1673-5374.272571] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/02/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease is the leading cause of dementia. Its increased prevalence in developed countries, due to the sharp rise in ageing populations, presents one of the costliest challenges to modern medicine. In order to find disease-modifying therapies to confront this challenge, a more complete understanding of the pathogenesis of Alzheimer's disease is necessary. Recent studies have revealed increasing evidence for the roles played by microglia, the resident innate immune system cells of the brain. Reflecting the well-established roles of microglia in reacting to pathogens and inflammatory stimuli, there is now a growing literature describing both protective and detrimental effects for individual cytokines and chemokines produced by microglia in Alzheimer's disease. A smaller but increasing number of studies have also addressed the divergent roles played by microglial neurotrophic and neurogenic factors, and how their perturbation may play a key role in the pathogenesis of Alzheimer's disease. Here we review recent findings on the roles played by microglia in neuroinflammation, neuronal survival and neurogenesis in Alzheimer's disease. In each case, landmark studies have provided evidence for the divergent ways in which microglia can either promote neuronal function and survival, or perturb neuronal function, leading to cell death. In many cases, the secreted molecules of microglia can lead to divergent effects depending on the magnitude and context of microglial activation. This suggests that microglial functions must be maintained in a fine equilibrium, in order to support healthy neuronal function, and that the cellular microenvironment in the Alzheimer's disease brain disrupts this fine balance, leading to neurodegeneration. Thus, an understanding of microglial homeostasis, both in health and across the trajectory of the disease state, will improve our understanding of the pathogenic mechanisms underlying Alzheimer's disease, and will hopefully lead to the development of microglial-based therapeutic strategies to restore equilibrium in the Alzheimer's disease brain.
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Affiliation(s)
- Sophie C. Gray
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Kerri J. Kinghorn
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Nathaniel S. Woodling
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, London, UK
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176
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A transcriptional toolbox for exploring peripheral neuroimmune interactions. Pain 2020; 161:2089-2106. [DOI: 10.1097/j.pain.0000000000001914] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/16/2020] [Indexed: 12/28/2022]
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177
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Abstract
Highlights In the current review, we thoroughly reviewed 74 identified articles regarding genes and genetic loci that confer susceptibility to ET. Over 50 genes/genetic loci have been examined for possible association with ET, but consistent results failed to be reported raising the need for collaborative multiethnic studies. Background: Essential tremor (ET) is a common movement disorder, which is mainly characterized by bilateral tremor (postural and/or kinetic) in the upper limbs, with other parts of the body possibly involved. While the pathophysiology of ET is still unclear, there is accumulating evidence indicating that genetic variability may be heavily involved in ET pathogenesis. This review focuses on the role of genetic risk factors in ET susceptibility. Methods: The PubMed database was searched for articles written in English, for studies with humans with ET, controls without ET, and genetic variants. The terms “essential tremor” and “polymorphism” (as free words) were used during search. We also performed meta-analyses for the most examined genetic variants. Results: Seventy four articles concerning LINGO1, LINGO2, LINGO4, SLC1A2, STK32B, PPARGC1A, CTNNA3, DRD3, ALAD, VDR, HMOX1, HMOX2, LRRK1,LRRK2, GBA, SNCA, MAPT, FUS, CYPsIL17A, IL1B, NOS1, ADH1B, TREM2, RIT2, HNMT, MTHFR, PPP2R2B, GSTP1, PON1, GABA receptors and GABA transporter, HS1BP3, ADH2, hSKCa3 and CACNL1A4 genes, and ETM genetic loci were included in the current review. Results from meta-analyses revealed a marginal association for the STK32B rs10937625 and a marginal trend for association (in sensitivity analysis) for the LINGO1 rs9652490, with ET. Discussion: Quite a few variants have been examined for their possible association with ET. LINGO1 rs9652490 and STK32B rs10937625 appear to influence, to some extent, ET susceptibility. However, the conflicting results and the lack of replication for many candidate genes raise the need for collaborative multiethnic studies.
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178
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Deczkowska A, Weiner A, Amit I. The Physiology, Pathology, and Potential Therapeutic Applications of the TREM2 Signaling Pathway. Cell 2020; 181:1207-1217. [DOI: 10.1016/j.cell.2020.05.003] [Citation(s) in RCA: 143] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/15/2020] [Accepted: 04/30/2020] [Indexed: 12/20/2022]
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179
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Zheng SH, Yan CY, Duan N, Wang W, Mei XP. Penehyclidine hydrochloride suppressed peripheral nerve injury-induced neuropathic pain by inhibiting microglial MAPK/p-p38/IL-1 β pathway activation. Mol Pain 2020; 15:1744806919858260. [PMID: 31149893 PMCID: PMC6589961 DOI: 10.1177/1744806919858260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Millions of people suffered from neuropathic pain, which is related to neuroinflammation in the central nervous system. Penehyclidine hydrochloride is a premedication of general anesthesia, which has been confirmed possessing neuroprotective effects against various neurodegenerative or neuroinflammatory diseases. However, it is not clear that whether penehyclidine hydrochloride could suppress neuropathic pain through its anti-neuroinflammatory effects. Methods This study investigated the effects of penehyclidine hydrochloride on rat spinal nerve ligation injury-induced neuropathic pain with behavioral, morphological, and molecular biological methods in animals. Results The results indicated that penehyclidine hydrochloride could attenuate spinal nerve ligation-induced neuropathic pain without any motor impairment and had no effect on sham-operated animals after repeated intraperitoneal administration. Intraperitoneal penehyclidine hydrochloride could suppress spinal nerve ligation-induced ipsilateral spinal dorsal horn microglial activation with downregulation of OX42 expression. Moreover, intraperitoneal penehyclidine hydrochloride inhibited spinal nerve ligation-induced spinal p-p38 mitogen-activated protein kinase expression, which was specially colocalized with the spinal dorsal horn microglia. Furthermore, intraperitoneal penehyclidine hydrochloride could depress spinal neuroinflammation by suppressing spinal nerve ligation-induced interleukin (IL)-1β over-expression. Conclusion These results indicated that the anti-allodynic effects of penehyclidine hydrochloride on spinal nerve ligation-induced neuropathic pain did not rely on motor impairment. Inhibiting spinal microglial p-p38/IL-1β pathway activation might contribute to the anti-allodynic effect of penehyclidine hydrochloride on nerve injury-induced neuropathic pain.
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Affiliation(s)
- Shao-Hua Zheng
- 1 Department of Anesthesiology, First Affiliated Hospital of Xi'an JiaoTong University, Xi'an, Shaanxi, China
| | - Chao-Ying Yan
- 1 Department of Anesthesiology, First Affiliated Hospital of Xi'an JiaoTong University, Xi'an, Shaanxi, China
| | - Na Duan
- 1 Department of Anesthesiology, First Affiliated Hospital of Xi'an JiaoTong University, Xi'an, Shaanxi, China
| | - Wei Wang
- 2 State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiao-Peng Mei
- 1 Department of Anesthesiology, First Affiliated Hospital of Xi'an JiaoTong University, Xi'an, Shaanxi, China
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180
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Microglial and Astrocytic Function in Physiological and Pathological Conditions: Estrogenic Modulation. Int J Mol Sci 2020; 21:ijms21093219. [PMID: 32370112 PMCID: PMC7247358 DOI: 10.3390/ijms21093219] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/24/2020] [Accepted: 04/30/2020] [Indexed: 12/20/2022] Open
Abstract
There are sexual differences in the onset, prevalence, and outcome of numerous neurological diseases. Thus, in Alzheimer’s disease, multiple sclerosis, and major depression disorder, the incidence in women is higher than in men. In contrast, men are more likely to present other pathologies, such as amyotrophic lateral sclerosis, Parkinson’s disease, and autism spectrum. Although the neurological contribution to these diseases has classically always been studied, the truth is that neurons are not the only cells to be affected, and there are other cells, such as glial cells, that are also involved and could be key to understanding the development of these pathologies. Sexual differences exist not only in pathology but also in physiological processes, which shows how cells are differentially regulated in males and females. One of the reasons these sexual differences may occur could be due to the different action of sex hormones. Many studies have shown an increase in aromatase levels in the brain, which could indicate the main role of estrogens in modulating proinflammatory processes. This review will highlight data about sex differences in glial physiology and how estrogenic compounds, such as estradiol and tibolone, could be used as treatment in neurological diseases due to their anti-inflammatory effects and the ability to modulate glial cell functions.
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181
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Drost N, Houtman J, Cseresnyés Z, Niesner R, Rinnenthal JL, Miller KR, Prokop S, Heppner FL. The Amyloid-beta rich CNS environment alters myeloid cell functionality independent of their origin. Sci Rep 2020; 10:7152. [PMID: 32346002 PMCID: PMC7189379 DOI: 10.1038/s41598-020-63989-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 04/02/2020] [Indexed: 01/08/2023] Open
Abstract
Microglia, the innate immune cells of the central nervous system (CNS) survey their surroundings with their cytoplasmic processes, phagocytose debris and rapidly respond to injury. These functions are affected by the presence of beta-Amyloid (Aβ) deposits, hallmark lesions of Alzheimer's disease (AD). We recently demonstrated that exchanging functionally altered endogenous microglia with peripheral myeloid cells did not change Aβ-burden in a mouse model mimicking aspects of AD at baseline, and only mildly reduced Aβ plaques upon stimulation. To better characterize these different myeloid cell populations, we used long-term in vivo 2-photon microscopy to compare morphology and basic functional parameters of brain populating peripherally-derived myeloid cells and endogenous microglia. While peripherally-derived myeloid cells exhibited increased process movement in the non-diseased brain, the Aβ rich environment in an AD-like mouse model, which induced an alteration of surveillance functions in endogenous microglia, also restricted functional characteristics and response to CNS injury of newly recruited peripherally-derived myeloid cells. Our data demonstrate that the Aβ rich brain environment alters the functional characteristics of endogenous microglia as well as newly recruited peripheral myeloid cells, which has implications for the role of myeloid cells in disease and the utilization of these cells in Alzheimer's disease therapy.
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Affiliation(s)
- Natalia Drost
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
| | - Judith Houtman
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, 01307, Dresden, Germany
| | - Zoltán Cseresnyés
- Deutsches Rheuma-Forschungszentrum Berlin, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Raluca Niesner
- Deutsches Rheuma-Forschungszentrum Berlin, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany
- Veterinary Medicine, Freie Universität, Berlin, Oertzenweg 19b, 14163, Berlin, Germany
| | - Jan-Leo Rinnenthal
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
- Department of Pathology, Sana Klinikum Offenbach, 63069, Offenbach, Germany
| | - Kelly R Miller
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
- Nanostring Technologies, Seattle, WA, USA
| | - Stefan Prokop
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
- Department of Pathology, University of Florida, Gainesville, FL, United States
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States
- Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Frank L Heppner
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117, Berlin, Germany.
- Cluster of Excellence, NeuroCure, Charitéplatz 1, 10117, Berlin, Germany.
- Berlin Institute of Health (BIH), 10117, Berlin, Germany.
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany.
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182
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Götzl JK, Brendel M, Werner G, Parhizkar S, Sebastian Monasor L, Kleinberger G, Colombo AV, Deussing M, Wagner M, Winkelmann J, Diehl-Schmid J, Levin J, Fellerer K, Reifschneider A, Bultmann S, Bartenstein P, Rominger A, Tahirovic S, Smith ST, Madore C, Butovsky O, Capell A, Haass C. Opposite microglial activation stages upon loss of PGRN or TREM2 result in reduced cerebral glucose metabolism. EMBO Mol Med 2020; 11:emmm.201809711. [PMID: 31122931 PMCID: PMC6554672 DOI: 10.15252/emmm.201809711] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Microglia adopt numerous fates with homeostatic microglia (HM) and a microglial neurodegenerative phenotype (MGnD) representing two opposite ends. A number of variants in genes selectively expressed in microglia are associated with an increased risk for neurodegenerative diseases such as Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). Among these genes are progranulin (GRN) and the triggering receptor expressed on myeloid cells 2 (TREM2). Both cause neurodegeneration by mechanisms involving loss of function. We have now isolated microglia from Grn−/− mice and compared their transcriptomes to those of Trem2−/−mice. Surprisingly, while loss of Trem2 enhances the expression of genes associated with a homeostatic state, microglia derived from Grn−/− mice showed a reciprocal activation of the MGnD molecular signature and suppression of gene characteristic for HM. The opposite mRNA expression profiles are associated with divergent functional phenotypes. Although loss of TREM2 and progranulin resulted in opposite activation states and functional phenotypes of microglia, FDG (fluoro‐2‐deoxy‐d‐glucose)‐μPET of brain revealed reduced glucose metabolism in both conditions, suggesting that opposite microglial phenotypes result in similar wide spread brain dysfunction.
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Affiliation(s)
- Julia K Götzl
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Georg Werner
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Samira Parhizkar
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Gernot Kleinberger
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | | | - Maximilian Deussing
- Department of Nuclear Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Matias Wagner
- Institut für Neurogenomik, Helmholtz Zentrum München, Munich, Germany.,Institut of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Juliane Winkelmann
- Institut für Neurogenomik, Helmholtz Zentrum München, Munich, Germany.,Institut of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Johannes Levin
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Department of Neurology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Katrin Fellerer
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Anika Reifschneider
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sebastian Bultmann
- Department of Biology and Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians-Universität München, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Axel Rominger
- Department of Nuclear Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Scott T Smith
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charlotte Madore
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Evergrande Center for Immunologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Anja Capell
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Christian Haass
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany .,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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183
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Zhang X, Wang D, Zhang B, Zhu J, Zhou Z, Cui L. Regulation of microglia by glutamate and its signal pathway in neurodegenerative diseases. Drug Discov Today 2020; 25:1074-1085. [PMID: 32320851 DOI: 10.1016/j.drudis.2020.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/10/2020] [Accepted: 04/03/2020] [Indexed: 02/06/2023]
Abstract
Microglia are an essential component of the central nervous system (CNS) and are involved in the primary response to microorganisms, neuroinflammation, homeostasis, and tissue regeneration, as well as contributing to the pathogenesis of neurodegenerative diseases. Research has shown that microglial diversity, multifunctionality, and their relationship with glutamate are crucial to determining their roles in these diseases. In this review, we focus on recent progress in determining microglial characteristics and the role of glutamate and its receptors in microglia regulation, which could be a novel therapeutic strategy for neurodegenerative diseases.
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Affiliation(s)
- Xinyue Zhang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China; Department of Neurobiology, Care Sciences & Society, Division of Neurogeriatrics, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
| | - Dan Wang
- Department of Ophthalmology, the First Hospital of Jilin University, Changchun, China.
| | - Bo Zhang
- Department of Neurobiology, Care Sciences & Society, Division of Neurogeriatrics, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden; Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China.
| | - Jie Zhu
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China; Department of Neurobiology, Care Sciences & Society, Division of Neurogeriatrics, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
| | - Zhulin Zhou
- Department of Neurobiology, Care Sciences & Society, Division of Neurogeriatrics, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
| | - Li Cui
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China.
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184
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Newby D, Prieto-Alhambra D, Duarte-Salles T, Ansell D, Pedersen L, van der Lei J, Mosseveld M, Rijnbeek P, James G, Alexander M, Egger P, Podhorna J, Stewart R, Perera G, Avillach P, Grosdidier S, Lovestone S, Nevado-Holgado AJ. Methotrexate and relative risk of dementia amongst patients with rheumatoid arthritis: a multi-national multi-database case-control study. ALZHEIMERS RESEARCH & THERAPY 2020; 12:38. [PMID: 32252806 PMCID: PMC7137292 DOI: 10.1186/s13195-020-00606-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 03/23/2020] [Indexed: 01/04/2023]
Abstract
Background Inflammatory processes have been shown to play a role in dementia. To understand this role, we selected two anti-inflammatory drugs (methotrexate and sulfasalazine) to study their association with dementia risk. Methods A retrospective matched case-control study of patients over 50 with rheumatoid arthritis (486 dementia cases and 641 controls) who were identified from electronic health records in the UK, Spain, Denmark and the Netherlands. Conditional logistic regression models were fitted to estimate the risk of dementia. Results Prior methotrexate use was associated with a lower risk of dementia (OR 0.71, 95% CI 0.52–0.98). Furthermore, methotrexate use with therapy longer than 4 years had the lowest risk of dementia (odds ratio 0.37, 95% CI 0.17–0.79). Sulfasalazine use was not associated with dementia (odds ratio 0.88, 95% CI 0.57–1.37). Conclusions Further studies are still required to clarify the relationship between prior methotrexate use and duration as well as biological treatments with dementia risk.
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Affiliation(s)
- Danielle Newby
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK.
| | - Daniel Prieto-Alhambra
- Centre for Statistics in Medicine, NDORMS, University of Oxford, Oxford, UK.,Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain
| | - Talita Duarte-Salles
- Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain
| | | | - Lars Pedersen
- Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
| | - Johan van der Lei
- Department of Medical Informatics, Erasmus Universitair Medisch Centrum, Rotterdam, Netherlands
| | - Mees Mosseveld
- Department of Medical Informatics, Erasmus Universitair Medisch Centrum, Rotterdam, Netherlands
| | - Peter Rijnbeek
- Department of Medical Informatics, Erasmus Universitair Medisch Centrum, Rotterdam, Netherlands
| | - Glen James
- Real World Data, GlaxoSmithKline, Uxbridge, UK
| | | | - Peter Egger
- Real World Data, GlaxoSmithKline, Uxbridge, UK
| | - Jana Podhorna
- Boehringer Ingelheim International GmbH, Medicine CNS & Emerging Areas, Ingelheim am Rhein, Germany
| | - Robert Stewart
- Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,South London and Maudsley NHS Foundation Trust, London, UK
| | - Gayan Perera
- Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Paul Avillach
- Department of Biomedical Informatics, Harvard Medical School, Boston, USA.,Department of Medical Informatics, Erasmus Universitair Medisch Centrum, Rotterdam, Netherlands
| | - Solène Grosdidier
- Department of Medical Informatics, Erasmus Universitair Medisch Centrum, Rotterdam, Netherlands
| | - Simon Lovestone
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK.,Janssen-Cilag', Beerse, Belgium
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185
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Berner DK, Wessolowski L, Armbrust F, Schneppenheim J, Schlepckow K, Koudelka T, Scharfenberg F, Lucius R, Tholey A, Kleinberger G, Haass C, Arnold P, Becker‐Pauly C. Meprin β cleaves TREM2 and controls its phagocytic activity on macrophages. FASEB J 2020; 34:6675-6687. [DOI: 10.1096/fj.201902183r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/03/2019] [Accepted: 03/12/2020] [Indexed: 11/11/2022]
Affiliation(s)
| | - Luisa Wessolowski
- Unit for Degradomics of the Protease Web, Biochemical Institute University of Kiel Kiel Germany
| | - Fred Armbrust
- Unit for Degradomics of the Protease Web, Biochemical Institute University of Kiel Kiel Germany
| | | | - Kai Schlepckow
- German Center for Neurodegenerative Diseases (DZNE) Munich Germany
| | - Tomas Koudelka
- Systematic Proteomics & Bioanalytics Institute for Experimental Medicine University of Kiel Kiel Germany
| | - Franka Scharfenberg
- Unit for Degradomics of the Protease Web, Biochemical Institute University of Kiel Kiel Germany
| | - Ralph Lucius
- Anatomical Institute University of Kiel Kiel Germany
| | - Andreas Tholey
- Systematic Proteomics & Bioanalytics Institute for Experimental Medicine University of Kiel Kiel Germany
| | - Gernot Kleinberger
- Biomedical Center, Biochemistry Ludwig‐Maximilians‐Universität Munich Munich Germany
- Munich Cluster for Systems Neurology Munich Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich Germany
- Biomedical Center, Biochemistry Ludwig‐Maximilians‐Universität Munich Munich Germany
- Munich Cluster for Systems Neurology Munich Germany
| | | | - Christoph Becker‐Pauly
- Unit for Degradomics of the Protease Web, Biochemical Institute University of Kiel Kiel Germany
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186
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Zhou M, Xu R, Kaelber DC, Gurney ME. Tumor Necrosis Factor (TNF) blocking agents are associated with lower risk for Alzheimer's disease in patients with rheumatoid arthritis and psoriasis. PLoS One 2020; 15:e0229819. [PMID: 32203525 PMCID: PMC7089534 DOI: 10.1371/journal.pone.0229819] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 02/16/2020] [Indexed: 01/03/2023] Open
Abstract
This large, retrospective case-control study of electronic health records from 56 million unique adult patients examined whether or not treatment with a Tumor Necrosis Factor (TNF) blocking agent is associated with lower risk for Alzheimer’s disease (AD) in patients with rheumatoid arthritis (RA), psoriasis, and other inflammatory diseases which are mediated in part by TNF and for which a TNF blocker is an approved treatment. The analysis compared the diagnosis of AD as an outcome measure in patients receiving at least one prescription for a TNF blocking agent (etanercept, adalimumab, and infliximab) or for methotrexate. Adjusted odds ratios (AORs) were estimated using the Cochran-Mantel-Haenszel (CMH) method and presented with 95% confidence intervals (CIs) and p-values. RA was associated with a higher risk for AD (Adjusted Odds Ratio (AOR) = 2.06, 95% Confidence Interval: (2.02–2.10), P-value <0.0001) as did psoriasis (AOR = 1.37 (1.31–1.42), P <0.0001), ankylosing spondylitis (AOR = 1.57 (1.39–1.77), P <0.0001), inflammatory bowel disease (AOR = 2.46 (2.33–2.59), P < 0.0001), ulcerative colitis (AOR = 1.82 (1.74–1.91), P <0.0001), and Crohn’s disease (AOR = 2.33 (2.22–2.43), P <0.0001). The risk for AD in patients with RA was lower among patients treated with etanercept (AOR = 0.34 (0.25–0.47), P <0.0001), adalimumab (AOR = 0.28 (0.19–0.39), P < 0.0001), or infliximab (AOR = 0.52 (0.39–0.69), P <0.0001). Methotrexate was also associated with a lower risk for AD (AOR = 0.64 (0.61–0.68), P <0.0001), while lower risk was found in patients with a prescription history for both a TNF blocker and methotrexate. Etanercept and adalimumab also were associated with lower risk for AD in patients with psoriasis: AOR = 0.47 (0.30–0.73 and 0.41 (0.20–0.76), respectively. There was no effect of gender or race, while younger patients showed greater benefit from a TNF blocker than did older patients. This study identifies a subset of patients in whom systemic inflammation contributes to risk for AD through a pathological mechanism involving TNF and who therefore may benefit from treatment with a TNF blocking agent.
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Affiliation(s)
- Mengshi Zhou
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Rong Xu
- Center for Artificial Intelligence in Drug Discovery, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
- * E-mail: (R.X.); (M.E.G.)
| | - David C. Kaelber
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
- Departments of Internal Medicine and Pediatrics and the Center for Clinical Informatics Research and Education, The MetroHealth System, Cleveland, OH, United States of America
| | - Mark E. Gurney
- Tetra Therapeutics, Grand Rapids, MI, United States of America
- * E-mail: (R.X.); (M.E.G.)
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187
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Yahaya MAF, Zolkiffly SZI, Moklas MAM, Hamid HA, Stanslas J, Zainol M, Mehat MZ. Possible Epigenetic Role of Vitexin in Regulating Neuroinflammation in Alzheimer's Disease. J Immunol Res 2020; 2020:9469210. [PMID: 32258178 PMCID: PMC7085883 DOI: 10.1155/2020/9469210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 02/24/2020] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) has been clinically characterized by a progressive degeneration of neurons which resulted in a gradual and irreversible cognitive impairment. The accumulation of Aβ and τ proteins in the brain contribute to the severity of the disease. Recently, vitexin compound has been the talk amongst researchers due to its pharmacological properties as anti-inflammation and anti-AD. However, the epigenetic mechanism of the compound in regulating the neuroinflammation activity is yet to be fully elucidated. Hence, this review discusses the potential of vitexin compound to have the pharmacoepigenetic property in regulating the neuroinflammation activity in relation to AD. It is with hope that the review would unveil the potential of vitexin as the candidate in treating AD.
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Affiliation(s)
- M. A. F. Yahaya
- Department of Human Anatomy, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - S. Z. I. Zolkiffly
- Department of Human Anatomy, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - M. A. M. Moklas
- Department of Human Anatomy, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - H. Abdul Hamid
- Department of Human Anatomy, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - J. Stanslas
- Department of Medicine, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - M. Zainol
- Herbal Medicine Research Centre, Institute for Medical Research, Jalan Pahang, Kuala Lumpur, Malaysia
| | - M. Z. Mehat
- Department of Human Anatomy, Faculty of Medicine & Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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188
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Nugent AA, Lin K, van Lengerich B, Lianoglou S, Przybyla L, Davis SS, Llapashtica C, Wang J, Kim DJ, Xia D, Lucas A, Baskaran S, Haddick PC, Lenser M, Earr TK, Shi J, Dugas JC, Andreone BJ, Logan T, Solanoy HO, Chen H, Srivastava A, Poda SB, Sanchez PE, Watts RJ, Sandmann T, Astarita G, Lewcock JW, Monroe KM, Di Paolo G. TREM2 Regulates Microglial Cholesterol Metabolism upon Chronic Phagocytic Challenge. Neuron 2020; 105:837-854.e9. [DOI: 10.1016/j.neuron.2019.12.007] [Citation(s) in RCA: 207] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 08/07/2019] [Accepted: 12/04/2019] [Indexed: 12/26/2022]
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189
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Liu J, Zhang T, Wang Y, Si C, Wang X, Wang RT, Lv Z. Baicalin ameliorates neuropathology in repeated cerebral ischemia-reperfusion injury model mice by remodeling the gut microbiota. Aging (Albany NY) 2020; 12:3791-3806. [PMID: 32084011 PMCID: PMC7066900 DOI: 10.18632/aging.102846] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/04/2020] [Indexed: 04/14/2023]
Abstract
We investigated the neuroprotective effects of baicalin and the role of gut microbiota in a mouse model of cerebral ischemia-reperfusion injury. Repeated cerebral ischemia-reperfusion significantly increased plasma levels of trimethylamine (TMA), trimethylamine-N-oxide (TMAO), and clusterin (a neuroinflammation biomarker). These changes correlated with cognitive decline; short-term memory deficits; abnormal long term potentiation (LTP); decreased functional connectivity (FC) between various brain regions; reduced plasticity and dendritic spine density in the hippocampus; increased levels of the pro-inflammatory cytokines IL-1β, IL-6, and TNFα; and altered the gut microbial composition. Treatment with 50-100 mg/Kg baicalin for 7 days after cerebral ischemia-reperfusion significantly restored normal plasma levels of TMA, TMAO, and clusterin. Baicalin treatment also suppressed neuroinflammation, remodeled the gut microbial composition back to normal, and improved cognition, memory, LTP, cerebral FC, and hippocampal neuronal plasticity. The neuroprotective effects of baicalin were diminished when mice undergoing repeated cerebral ischemia-reperfusion were pretreated with broad-spectrum antibiotics to deplete gut microbial populations. This suggests the neuroprotective effects of baicalin in cerebral ischemia-reperfusion injury are mediated by the gut microbiota. It thus appears that baicalin ameliorates neuropathology in a repeated cerebral ischemia-reperfusion model mice by remodeling the gut microbiota.
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Affiliation(s)
- Jianfeng Liu
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Tianhua Zhang
- Department of Vascular Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China
| | - Yingying Wang
- Department of Computer Science, Hong Kong Baptist University, Hong Kong, China
| | - Chengqing Si
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Xudong Wang
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Rui-Tao Wang
- Department of Internal Medicine, Harbin Medical University Cancer Hospital, Harbin Medical University, Harbin 150081, China
| | - Zhonghua Lv
- Department of Neurosurgery, Harbin Medical University Cancer Hospital, Harbin Medical University, Harbin 150081, China
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190
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Trem2 Deletion Reduces Late-Stage Amyloid Plaque Accumulation, Elevates the Aβ42:Aβ40 Ratio, and Exacerbates Axonal Dystrophy and Dendritic Spine Loss in the PS2APP Alzheimer's Mouse Model. J Neurosci 2020; 40:1956-1974. [PMID: 31980586 PMCID: PMC7046459 DOI: 10.1523/jneurosci.1871-19.2019] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/08/2019] [Accepted: 12/23/2019] [Indexed: 01/17/2023] Open
Abstract
TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. Plaque abundance was elevated in PS2APP;Trem2ko females at 6–7 months; but by 12 or 19–22 months of age, it was notably diminished in female and male PS2APP;Trem2ko mice, respectively. Across all ages, plaque morphology was more diffuse in PS2APP;Trem2ko brains, and the Aβ42:Aβ40 ratio was elevated. The amount of soluble, fibrillar Aβ oligomers also increased in PS2APP;Trem2ko hippocampi. Associated with these changes, axonal dystrophy was exacerbated from 6 to 7 months onward in PS2APP;Trem2ko mice, notwithstanding the reduced plaque load at later ages. PS2APP;Trem2ko mice also exhibited more dendritic spine loss around plaque and more neurofilament light chain in CSF. Thus, aggravated neuritic dystrophy is a more consistent outcome of Trem2 deficiency than amyloid plaque load, suggesting that the microglial packing of Aβ into dense plaque is an important neuroprotective activity. SIGNIFICANCE STATEMENT Genetic studies indicate that TREM2 gene mutations confer increased Alzheimer's disease (AD) risk. We studied the effects of Trem2 deletion in the PS2APP mouse AD model, in which overproduction of Aβ peptide leads to amyloid plaque formation and associated neuritic dystrophy. Interestingly, neuritic dystrophies were intensified in the brains of Trem2-deficient mice, despite these mice displaying reduced plaque accumulation at later ages (12–22 months). Microglial clustering around plaques was impaired, plaques were more diffuse, and the Aβ42:Aβ40 ratio and amount of soluble, fibrillar Aβ oligomers were elevated in Trem2-deficient brains. These results suggest that the Trem2-dependent compaction of Aβ into dense plaques is a protective microglial activity, limiting the exposure of neurons to toxic Aβ species.
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191
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Brioschi S, Zhou Y, Colonna M. Brain Parenchymal and Extraparenchymal Macrophages in Development, Homeostasis, and Disease. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:294-305. [PMID: 31907272 PMCID: PMC7034672 DOI: 10.4049/jimmunol.1900821] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/27/2019] [Indexed: 12/23/2022]
Abstract
Microglia are parenchymal macrophages of the CNS; as professional phagocytes they are important for maintenance of the brain's physiology. These cells are generated through primitive hematopoiesis in the yolk sac and migrate into the brain rudiment after establishment of embryonic circulation. Thereafter, microglia develop in a stepwise fashion, reaching complete maturity after birth. In the CNS, microglia self-renew without input from blood monocytes. Recent RNA-sequencing studies have defined a molecular signature for microglia under homeostasis. However, during disease, microglia undergo remarkable phenotypic changes, which reflect the acquisition of specialized functions tailored to the pathological context. In addition to microglia, the brain-border regions host populations of extraparenchymal macrophages with disparate origins and phenotypes that have recently been delineated. In this review we outline recent findings that provide a deeper understanding of both parenchymal microglia and extraparenchymal brain macrophages in homeostasis and during disease.
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Affiliation(s)
- Simone Brioschi
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110
| | - Yingyue Zhou
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110
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192
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Wang Q, Xu Y, Qi C, Liu A, Zhao Y. Association study of serum soluble TREM2 with vascular dementia in Chinese Han population. Int J Neurosci 2020; 130:708-712. [PMID: 31847649 DOI: 10.1080/00207454.2019.1702548] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Objective: Recent extensive evidence suggests that the triggering receptor expressed on myeloid cells 2 (TREM2) is closely implicated in the pathogenesis of Alzheimer's disease (AD). However, no relative data exist regarding vascular dementia (VD). This study aimed to investigate the association between serum soluble TREM2 (sTREM2) and vascular dementia in Chinese Han population.Methods: A total of 120 VD patients and 120 cognitively normal controls matched for age and gender were enrolled for this study. Demographic and clinical characteristics were recorded at admission. Cognitive functions were assessed by the Mini-Mental State Examination (MMSE) and serum sTREM2 levels were detected using sandwich ELISA method.Results: Demographic and clinical characteristics did not differ dramatically between groups. Serum sTREM2 levels in VD patients are significantly decreased compared with normal controls. In VD patients, the serum sTREM2 levels were positively correlated with MMSE scores (r = 0.387, p = 0.008), and the association was independent of demographic and clinical characteristics (β = 0.396, p < 0.001).Conclusion: VD patients have significantly lower serum sTREM2 levels in comparison to normal controls. Serum sTREM2 levels may be used as a potential predictive biomarker of cognitive decline in VD.
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Affiliation(s)
- Qian Wang
- Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China.,Department of Central Laboratory, Taian City Central Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong Province, China
| | - Yuzhen Xu
- Department of Neurology, Taian City Central Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong Province, China
| | - Chunhua Qi
- Department of Central Laboratory, Taian City Central Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong Province, China
| | - Aihua Liu
- Department of Central Laboratory, Taian City Central Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong Province, China
| | - Yueran Zhao
- Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
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193
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Singh AK, Mishra G, Maurya A, Awasthi R, Kumari K, Thakur A, Rai A, Rai GK, Sharma B, Kulkarni GT, Singh SK. Role of TREM2 in Alzheimer's Disease and its Consequences on β- Amyloid, Tau and Neurofibrillary Tangles. Curr Alzheimer Res 2020; 16:1216-1229. [DOI: 10.2174/1567205016666190903102822] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/21/2019] [Accepted: 08/21/2019] [Indexed: 11/22/2022]
Abstract
:
Alzheimer's Disease (AD) is age-related neurodegenerative disorder recognized by a steadily
gradual cognitive decline that has devastating personal and socioeconomic implications. Recently, some
genetic factors for AD have been identified which attracted wide attention of researchers in different
areas of AD biology and possible new therapeutic targets. Alternative forms of triggering receptor expressed
on myeloid cells 2 (TREM2) genes are examples of such risk factors, which contribute higher
risk for developing AD. Comprehending TREM2 function pledge to provide salient insight into how
neuroinflammation contributes to AD pathology. The dearth of microglial TREM2 shepherd to augmented
tau pathology is couple with frequent enhancement of activated neuronal stress kinases. The involvement
of TREM2 in the regulation of tau-associated innate immune response of the CNS has clearly
demonstrated through these findings. However, whether decrease level of TREM2 assists pathology of
tau through changed clearance and pathological escalation of tau or through direct contact between microglia
and neuron and any alternative possible mechanisms need to examine. This review briefly summarizes
distinct functional roles of TREM2 in AD pathology and highlights the TREM2 gene regulation.
We have also addressed the impact of TREM2 on β-amyloid plaques and tau pathology in Alzheimer’s
disease.
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Affiliation(s)
- Anurag K. Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Gaurav Mishra
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Anand Maurya
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Rajendra Awasthi
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Komal Kumari
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Abhimanyu Thakur
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Arati Rai
- Hygia Institute of Pharmaceutical Education & Research, Lucknow-226020, Uttar Pradesh, India
| | - Gopal Kumar Rai
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi- 221005, Uttar Pradesh, India
| | - Bhupesh Sharma
- Department of Pharmacology, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Giriraj T Kulkarni
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Santosh Kumar Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
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194
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Merlo S, Spampinato SF, Caruso GI, Sortino MA. The Ambiguous Role of Microglia in Aβ Toxicity: Chances for Therapeutic Intervention. Curr Neuropharmacol 2020; 18:446-455. [PMID: 32003695 PMCID: PMC7457435 DOI: 10.2174/1570159x18666200131105418] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/09/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023] Open
Abstract
Amyloid-β (Aβ) has long been shown to be critical in Alzheimer's disease pathophysiology. Microglia contributes to the earliest responses to Aβ buildup, by direct interaction through multiple receptors. Microglial cells operate Aβ clearance and trigger inflammatory/regenerative processes that take place in the long years of silent disease progression that precede symptomatic appearance. But in time and with aging, the fine balance between pro- and anti-inflammatory activity of microglia deranges, negatively impacting its Aβ-clearing ability. Furthermore, in recent years, microglial activation has proven to be much more complex than the mere dichotomic pro/antiinflammatory polarization previously accepted. Microglia can display a wide spectrum of phenotypes, which can even be mixed. On these bases, it is evident that while pharmacological intervention aiding microglia to prolong its ability to cope with Aβ buildup could be extremely relevant, its feasibility is hampered by such high complexity, which still needs to be completely understood.
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Affiliation(s)
- Sara Merlo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology; University of Catania, Catania, Italy
| | - Simona Federica Spampinato
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology; University of Catania, Catania, Italy
| | - Grazia Ilaria Caruso
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology; University of Catania, Catania, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology; University of Catania, Catania, Italy
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195
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Bortolotti D, Gentili V, Rotola A, Caselli E, Rizzo R. HHV-6A infection induces amyloid-beta expression and activation of microglial cells. ALZHEIMERS RESEARCH & THERAPY 2019; 11:104. [PMID: 31831060 PMCID: PMC6909659 DOI: 10.1186/s13195-019-0552-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/30/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND The control of viral infections in the brain involves the activation of microglial cells, the macrophages of the brain that are constantly surveying the central nervous system, and the production of amyloid-beta (Aβ) as an anti-microbial molecule. Recent findings suggest a possible implication of HHV-6A in AD. We evaluated the effect of HHV-6A infection on microglial cell expression Aβ and the activation status, determined by TREM2, ApoE, cytokines, and tau expression. METHODS We have infected microglial cells (HMC3, ATCC®CRL-3304), in monolayer and human peripheral blood monocyte-derived microglia (PBM-microglia) spheroid 3D model, with HHV-6A (strain U1102) cell-free virus inocula with 100 genome equivalents per 1 cell. We collected the cells 1, 3, 7, and 14 days post-infection (d.p.i.) and analyzed them for viral DNA and RNA, ApoE, Aβ (1-40, 1-42), tau, and phospho-tau (Threonine 181) by real-time immunofluorescence and cytokines by immunoenzymatic assay. RESULTS We observed a productive infection by HHV-6A. The expression of Aβ 1-42 increased from 3 d.p.i., while no significant induction was observed for Aβ 1-40. The HHV-6A infection induced the activation (TREM2, IL-1beta, ApoE) and migration of microglial cells. The secretion of tau started from 7 d.p.i., with an increasing percentage of the phosphorylated form. CONCLUSIONS In conclusion, microglial cells are permissive to HHV-6A infection that induces the expression of Aβ and an activation status. Meanwhile, we hypothesize a paracrine effect of HHV-6A infection that activates and induces microglia migration to the site of infection.
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Affiliation(s)
- Daria Bortolotti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Luigi Borsari, 46, 44121, Ferrara, Italy
| | - Valentina Gentili
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Luigi Borsari, 46, 44121, Ferrara, Italy
| | - Antonella Rotola
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Luigi Borsari, 46, 44121, Ferrara, Italy
| | - Elisabetta Caselli
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Luigi Borsari, 46, 44121, Ferrara, Italy
| | - Roberta Rizzo
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Luigi Borsari, 46, 44121, Ferrara, Italy.
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196
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Dean HB, Roberson ED, Song Y. Neurodegenerative Disease-Associated Variants in TREM2 Destabilize the Apical Ligand-Binding Region of the Immunoglobulin Domain. Front Neurol 2019; 10:1252. [PMID: 32021611 PMCID: PMC6985895 DOI: 10.3389/fneur.2019.01252] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/11/2019] [Indexed: 01/22/2023] Open
Abstract
Single nucleotide variations in Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) have been linked to both late-onset Alzheimer's disease and behavioral variant frontotemporal dementia (FTD), the latter presenting either in isolation or with cystic bone lesions in a condition called Nasu-Hakola disease. Models of the extracellular domain of TREM2 show that Nasu-Hakola disease-associated mutations are grossly inactivating by truncation, frameshift, or unfolding, that Alzheimer's disease (AD)-associated variants localize to a putative ligand-interacting region (PLIR) on the extracellular surface, and that FTD-associated variants are found in the hydrophobic core. However, while these disease-associated residues are predicted to play some role in disrupting ligand binding to the extracellular domain of TREM2, how they ultimately lead to disease remains unknown. Here, we used in silico molecular modeling to investigate all-atom models of TREM2 and characterize the effects on conformation and dynamical motion of AD-associated R47H and R62H as well as FTD-associated T96K, D86V, and T66M variants compared to the benign N68K variant and the common variant. Our model, which is based on a published 2.2 Å resolution crystal structure of the TREM2 extracellular domain, finds that both AD- and FTD-associated variants cause localized instability in three loops adjacent to the PLIR that correspond to the complementarity-determining regions (CDRs) of antibodies. This instability ultimately disrupts tethering between these CDRs and the core of the immunoglobulin domain, exposing a group of otherwise-buried, negatively charged residues. This instability and exposure of negatively charged residues is most severe following introduction of the T66M variant that has been described as causing FTD even in the heterozygous state and is less severe following introduction of variants that are less strongly tied to FTD or of those associated with AD. Thus, our results provide further evidence that the proposed loss-of-function caused by neurodegenerative disease-associated variants may be driven by altered conformational stability of the ligand-interacting CDR and, ultimately, loss of affinity or specificity for TREM2 ligands.
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Affiliation(s)
- Hunter B Dean
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.,Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, United States.,Alzheimer's Disease Center, University of Alabama at Birmingham, Birmingham, AL, United States.,Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Erik D Roberson
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.,Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, United States.,Alzheimer's Disease Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yuhua Song
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States
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197
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Prokop S, Lee VMY, Trojanowski JQ. Neuroimmune interactions in Alzheimer's disease-New frontier with old challenges? PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 168:183-201. [PMID: 31699314 PMCID: PMC6939624 DOI: 10.1016/bs.pmbts.2019.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The perceived role of the immune system in neurodegenerative diseases has undergone drastic changes over time. Initially considered as a passive bystander, then condemned as a mediator of neurodegeneration and now established as an important player in the pathogenetic cascade, neuroimmune interactions have come a long way to arrive center stage in Alzheimer's disease research. Despite major breakthroughs in recent years, basic questions remain unanswered as conflicting data describe immune overactivation, inadequate response or exhaustion of the immune system in neurodegenerative diseases. Furthermore, difficulties in translating in vitro and in vivo studies in model systems to the complex human disease condition with multiple overlapping pathologies and the long disease duration in patients suffering from neurodegenerative diseases have hampered progress. Development of novel, advanced model systems, as well as new technologies to interrogate existing disease models and valuable collections of human tissue samples, including brain tissue in parallel with improved imaging and biomarker technologies are guiding the way to better understand the role of the immune system in Alzheimer's disease with hopes for more effective interventions in the future.
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Affiliation(s)
- Stefan Prokop
- Department of Pathology, University of Florida, Gainesville, FL, United States; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States; Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States; McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
| | - Virginia M Y Lee
- Department of Pathology and Laboratory Medicine, AD Center Core (ADCC), Center for Neurodegenerative Disease Research, University of Pennsylvania (PENN), School of Medicine, Philadelphia, PA, United States
| | - John Q Trojanowski
- Department of Pathology and Laboratory Medicine, AD Center Core (ADCC), Center for Neurodegenerative Disease Research, University of Pennsylvania (PENN), School of Medicine, Philadelphia, PA, United States
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198
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Angelova DM, Brown DR. Microglia and the aging brain: are senescent microglia the key to neurodegeneration? J Neurochem 2019; 151:676-688. [PMID: 31478208 DOI: 10.1111/jnc.14860] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 12/15/2022]
Abstract
The single largest risk factor for etiology of neurodegenerative diseases like Alzheimer's disease is increased age. Therefore, understanding the changes that occur as a result of aging is central to any possible prevention or cure for such conditions. Microglia, the resident brain glial population most associated with both protection of neurons in health and their destruction is disease, could be a significant player in age related changes. Microglia can adopt an aberrant phenotype sometimes referred to either as dystrophic or senescent. While aged microglia have been frequently identified in neurodegenerative diseases such as Alzheimer's disease, there is no conclusive evidence that proves a causal role. This has been hampered by a lack of models of aged microglia. We have recently generated a model of senescent microglia based on the observation that all dystrophic microglia show iron overload. Iron-overloading cultured microglia causes them to take on a senescent phenotype and can cause changes in models of neurodegeneration similar to those observed in patients. This review considers how this model could be used to determine the role of senescent microglia in neurodegenerative diseases.
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Affiliation(s)
- Dafina M Angelova
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - David R Brown
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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199
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García-Revilla J, Alonso-Bellido IM, Burguillos MA, Herrera AJ, Espinosa-Oliva AM, Ruiz R, Cruz-Hernández L, García-Domínguez I, Roca-Ceballos MA, Santiago M, Rodríguez-Gómez JA, Soto MS, de Pablos RM, Venero JL. Reformulating Pro-Oxidant Microglia in Neurodegeneration. J Clin Med 2019; 8:E1719. [PMID: 31627485 PMCID: PMC6832973 DOI: 10.3390/jcm8101719] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/11/2019] [Accepted: 10/12/2019] [Indexed: 12/13/2022] Open
Abstract
In neurodegenerative diseases, microglia-mediated neuroinflammation and oxidative stress are central events. Recent genome-wide transcriptomic analyses of microglial cells under different disease conditions have uncovered a new subpopulation named disease-associated microglia (DAM). These studies have challenged the classical view of the microglia polarization state's proinflammatory M1 (classical activation) and immunosuppressive M2 (alternative activation). Molecular signatures of DAM and proinflammatory microglia (highly pro-oxidant) have shown clear differences, yet a partial overlapping gene profile is evident between both phenotypes. The switch activation of homeostatic microglia into reactive microglia relies on the selective activation of key surface receptors involved in the maintenance of brain homeostasis (a.k.a. pattern recognition receptors, PRRs). Two relevant PRRs are toll-like receptors (TLRs) and triggering receptors expressed on myeloid cells-2 (TREM2), whose selective activation is believed to generate either a proinflammatory or a DAM phenotype, respectively. However, the recent identification of endogenous disease-related ligands, which bind to and activate both TLRs and TREM2, anticipates the existence of rather complex microglia responses. Examples of potential endogenous dual ligands include amyloid β, galectin-3, and apolipoprotein E. These pleiotropic ligands induce a microglia polarization that is more complicated than initially expected, suggesting the possibility that different microglia subtypes may coexist. This review highlights the main microglia polarization states under disease conditions and their leading role orchestrating oxidative stress.
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Affiliation(s)
- Juan García-Revilla
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Isabel M Alonso-Bellido
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Miguel A Burguillos
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Antonio J Herrera
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Ana M Espinosa-Oliva
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Rocío Ruiz
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Luis Cruz-Hernández
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Irene García-Domínguez
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - María A Roca-Ceballos
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Marti Santiago
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - José A Rodríguez-Gómez
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Departament of Medical Physiology and Biophysics, Faculty of Medicine, University of Seville, 41009 Sevilla, Spain.
| | - Manuel Sarmiento Soto
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - Rocío M de Pablos
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
| | - José L Venero
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain.
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200
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Yao H, Coppola K, Schweig JE, Crawford F, Mullan M, Paris D. Distinct Signaling Pathways Regulate TREM2 Phagocytic and NFκB Antagonistic Activities. Front Cell Neurosci 2019; 13:457. [PMID: 31649511 PMCID: PMC6795686 DOI: 10.3389/fncel.2019.00457] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/25/2019] [Indexed: 11/13/2022] Open
Abstract
Several genetic variants of the Triggering Receptor Expressed on Myeloid Cells-2 (TREM2) have been shown to increase the risk of developing Alzheimer’s disease (AD) supporting a role of microglia and immune cells in the pathobiology of AD. We have employed an ectopic model of TREM2 and DAP12 expression in HEK293 cells to study selectively TREM2 dependent signaling and phagocytic functions and evaluated the effects of some of the TREM2 mutations associated with AD. We show that shedding of the TREM2 N-terminal domain does not affect the inhibition of NFκB activation induced by TREM2 while it completely blocks phagocytosis suggesting that TREM2 anti-inflammatory properties can be mediated by the TREM2 C-terminal fragment while the phagocytic activity requires the full-length receptor. In addition, we confirm in that model that apolipoprotein E (APOE) is a ligand for TREM2 and triggers TREM2 signaling. In particular, we show that APOE4 stimulates spleen tyrosine kinase (SYK) activation more potently than APOE2 in a TREM2 dependent manner. Interestingly, TREM2 appears to antagonize NFκB activation induced by phorbol ester but is unable to prevent TNFα induction of NFκB activation suggesting that TREM2 antagonizes inflammatory events triggered downstream of PKC. TREM2 mutations drastically impact TREM2 phagocytosis as well as its ability to antagonize NFκB activation and notably prevent the activation of the PI3K/AKT pathway observed with wild-type TREM2. Overall our data suggest that TREM2 dependent phagocytosis requires an activation of the SYK/PI3K/AKT/PLCγ pathways while the suppression of NFκB activation by TREM2 is independent of SYK, PI3K, and PLCγ activities. This model of ectopic TREM2-DAP12 co-expression appears suitable to study TREM2 signaling as several biological functions of TREM2 and TREM2 mutations that have been previously described in myeloid and microglial cells were also replicated in this model.
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Affiliation(s)
- Hailan Yao
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Kyle Coppola
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Jonas Elias Schweig
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Fiona Crawford
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Michael Mullan
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Daniel Paris
- The Roskamp Institute, Sarasota, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
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