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Cibelli A, Ballesteros-Gomez D, McCutcheon S, Yang GL, Bispo A, Krawchuk M, Piedra G, Spray DC. Astrocytes sense glymphatic-level shear stress through the interaction of sphingosine-1-phosphate with Piezo1. iScience 2024; 27:110069. [PMID: 38868201 PMCID: PMC11167526 DOI: 10.1016/j.isci.2024.110069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/09/2024] [Accepted: 05/17/2024] [Indexed: 06/14/2024] Open
Abstract
Astrocyte endfeet enwrap brain vasculature, forming a boundary for perivascular glymphatic flow of fluid and solutes along and across the astrocyte endfeet into the brain parenchyma. We evaluated astrocyte sensitivity to shear stress generated by such flow, finding a set point for downstream calcium signaling that is below about 0.1 dyn/cm2. This set point is modulated by albumin levels encountered in cerebrospinal fluid (CSF) under normal conditions and following a blood-brain barrier breach or immune response. The astrocyte mechanosome responsible for the detection of shear stress includes sphingosine-1-phosphate (S1P)-mediated sensitization of the mechanosensor Piezo1. Fluid flow through perivascular channels delimited by vessel wall and astrocyte endfeet thus generates sufficient shear stress to activate astrocytes, thereby potentially controlling vasomotion and parenchymal perfusion. Moreover, S1P receptor signaling establishes a set point for Piezo1 activation that is finely tuned to coincide with CSF albumin levels and to the low shear forces resulting from glymphatic flow.
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Affiliation(s)
- Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | - Sean McCutcheon
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Greta L. Yang
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ashley Bispo
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michael Krawchuk
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Giselle Piedra
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David C. Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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2
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Xing Q, Cibelli A, Yang GL, Dohare P, Li QH, Scemes E, Guan FX, Spray DC. Neuronal Panx1 drives peripheral sensitization in experimental plantar inflammatory pain. Mil Med Res 2024; 11:27. [PMID: 38685116 PMCID: PMC11057180 DOI: 10.1186/s40779-024-00525-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 03/25/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND The channel-forming protein Pannexin1 (Panx1) has been implicated in both human studies and animal models of chronic pain, but the underlying mechanisms remain incompletely understood. METHODS Wild-type (WT, n = 24), global Panx1 KO (n = 24), neuron-specific Panx1 KO (n = 20), and glia-specific Panx1 KO (n = 20) mice were used in this study at Albert Einstein College of Medicine. The von Frey test was used to quantify pain sensitivity in these mice following complete Freund's adjuvant (CFA) injection (7, 14, and 21 d). The qRT-PCR was employed to measure mRNA levels of Panx1, Panx2, Panx3, Cx43, Calhm1, and β-catenin. Laser scanning confocal microscopy imaging, Sholl analysis, and electrophysiology were utilized to evaluate the impact of Panx1 on neuronal excitability and morphology in Neuro2a and dorsal root ganglion neurons (DRGNs) in which Panx1 expression or function was manipulated. Ethidium bromide (EtBr) dye uptake assay and calcium imaging were employed to investigate the role of Panx1 in adenosine triphosphate (ATP) sensitivity. β-galactosidase (β-gal) staining was applied to determine the relative cellular expression levels of Panx1 in trigeminal ganglia (TG) and DRG of transgenic mice. RESULTS Global or neuron-specific Panx1 deletion markedly decreased pain thresholds after CFA stimuli (7, 14, and 21 d; P < 0.01 vs. WT group), indicating that Panx1 was positively correlated with pain sensitivity. In Neuro2a, global Panx1 deletion dramatically reduced neurite extension and inward currents compared to the WT group (P < 0.05), revealing that Panx1 enhanced neurogenesis and excitability. Similarly, global Panx1 deletion significantly suppressed Wnt/β-catenin dependent DRG neurogenesis following 5 d of nerve growth factor (NGF) treatment (P < 0.01 vs. WT group). Moreover, Panx1 channels enhanced DRG neuron response to ATP after CFA injection (P < 0.01 vs. Panx1 KO group). Furthermore, ATP release increased Ca2+ responses in DRGNs and satellite glial cells surrounding them following 7 d of CFA treatment (P < 0.01 vs. Panx1 KO group), suggesting that Panx1 in glia also impacts exaggerated neuronal excitability. Interestingly, neuron-specific Panx1 deletion was found to markedly reduce differentiation in cultured DRGNs, as evidenced by stunted neurite outgrowth (P < 0.05 vs. Panx1 KO group; P < 0.01 vs. WT group or GFAP-Cre group), blunted activation of Wnt/β-catenin signaling (P < 0.01 vs. WT, Panx1 KO and GFAP-Cre groups), and diminished cell excitability (P < 0.01 vs. GFAP-Cre group) and response to ATP stimulation (P < 0.01 vs. WT group). Analysis of β-gal staining showed that cellular expression levels of Panx1 in neurons are significantly higher (2.5-fold increase) in the DRG than in the TG. CONCLUSIONS The present study revealed that neuronal Panx1 is a prominent driver of peripheral sensitivity in the setting of inflammatory pain through cell-autonomous effects on neuronal excitability. This hyperexcitability dependence on neuronal Panx1 contrasts with inflammatory orofacial pain, where similar studies revealed a prominent role for glial Panx1. The apparent differences in Panx1 expression in neuronal and non-neuronal TG and DRG cells are likely responsible for the distinct impact of these cell types in the two pain models.
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Affiliation(s)
- Qu Xing
- School of Life Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Antonio Cibelli
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, 70125, Italy
| | - Greta Luyuan Yang
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, 06459, USA
| | - Preeti Dohare
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, 12208, USA
| | - Qing-Hua Li
- School of Life Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Eliana Scemes
- Department of Anatomy and Cell Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Fang-Xia Guan
- School of Life Sciences, Zhengzhou University, Zhengzhou, 450001, China.
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, 450001, China.
| | - David C Spray
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Lucero CM, Navarro L, Barros-Osorio C, Cáceres-Conejeros P, Orellana JA, Gómez GI. Activation of Pannexin-1 channels causes cell dysfunction and damage in mesangial cells derived from angiotensin II-exposed mice. Front Cell Dev Biol 2024; 12:1387234. [PMID: 38660621 PMCID: PMC11041381 DOI: 10.3389/fcell.2024.1387234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
Chronic kidney disease (CKD) is a prevalent health concern associated with various pathological conditions, including hypertensive nephropathy. Mesangial cells are crucial in maintaining glomerular function, yet their involvement in CKD pathogenesis remains poorly understood. Recent evidence indicates that overactivation of Pannexin-1 (Panx1) channels could contribute to the pathogenesis and progression of various diseases. Although Panx1 is expressed in the kidney, its contribution to the dysfunction of renal cells during pathological conditions remains to be elucidated. This study aimed to investigate the impact of Panx1 channels on mesangial cell function in the context of hypertensive nephropathy. Using an Ang II-infused mouse model and primary mesangial cell cultures, we demonstrated that in vivo exposure to Ang II sensitizes cultured mesangial cells to show increased alterations when they are subjected to subsequent in vitro exposure to Ang II. Particularly, mesangial cell cultures treated with Ang II showed elevated activity of Panx1 channels and increased release of ATP. The latter was associated with enhanced basal intracellular Ca2+ ([Ca2+]i) and increased ATP-mediated [Ca2+]i responses. These effects were accompanied by increased lipid peroxidation and reduced cell viability. Crucially, all the adverse impacts evoked by Ang II were prevented by the blockade of Panx1 channels, underscoring their critical role in mediating cellular dysfunction in mesangial cells. By elucidating the mechanisms by which Ang II negatively impacts mesangial cell function, this study provides valuable insights into the pathogenesis of renal damage in hypertensive nephropathy.
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Affiliation(s)
- Claudia M. Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Laura Navarro
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Cristián Barros-Osorio
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Patricio Cáceres-Conejeros
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I. Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
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4
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Wei C, Fu M, Zhang H, Yao B. How is the P2X7 receptor signaling pathway involved in epileptogenesis? Neurochem Int 2024; 173:105675. [PMID: 38211839 DOI: 10.1016/j.neuint.2024.105675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/13/2024]
Abstract
Epilepsy, a condition characterized by spontaneous recurrent epileptic seizures, is among the most prevalent neurological disorders. This disorder is estimated to affect approximately 70 million people worldwide. Although antiseizure medications are considered the first-line treatments for epilepsy, most of the available antiepileptic drugs are not effective in nearly one-third of patients. This calls for the development of more effective drugs. Evidence from animal models and epilepsy patients suggests that strategies that interfere with the P2X7 receptor by binding to adenosine triphosphate (ATP) are potential treatments for this patient population. This review describes the role of the P2X7 receptor signaling pathways in epileptogenesis. We highlight the genes, purinergic signaling, Pannexin1, glutamatergic signaling, adenosine kinase, calcium signaling, and inflammatory response factors involved in the process, and conclude with a synopsis of these key connections. By unraveling the intricate interplay between P2X7 receptors and epileptogenesis, this review provides ideas for designing potent clinical therapies that will revolutionize both prevention and treatment for epileptic patients.
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Affiliation(s)
- Caichuan Wei
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Miaoying Fu
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Haiju Zhang
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Baozhen Yao
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China.
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5
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McAllister BB, Stokes-Heck S, Harding EK, van den Hoogen NJ, Trang T. Targeting Pannexin-1 Channels: Addressing the 'Gap' in Chronic Pain. CNS Drugs 2024; 38:77-91. [PMID: 38353876 DOI: 10.1007/s40263-024-01061-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/07/2024] [Indexed: 02/22/2024]
Abstract
Chronic pain complicates many diseases and is notoriously difficult to treat. In search of new therapeutic targets, pannexin-1 (Panx1) channels have sparked intense interest as a key mechanism involved in a variety of chronic pain conditions. Panx1 channels are transmembrane proteins that release ions and small molecules, such as adenosine triphosphate (ATP). They are expressed along important nodes of the pain pathway, modulating activity of diverse cell types implicated in the development and progression of chronic pain caused by injury or pathology. This review highlights advances that have unlocked the core structure and machinery controlling Panx1 function with a focus on understanding and treating chronic pain.
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Affiliation(s)
- Brendan B McAllister
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Sierra Stokes-Heck
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Erika K Harding
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Nynke J van den Hoogen
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Tuan Trang
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada.
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Cibelli A, Dohare P, Spray DC, Scemes E. Differential activation of mouse and human Panx1 channel variants. PLoS One 2023; 18:e0295710. [PMID: 38100403 PMCID: PMC10723736 DOI: 10.1371/journal.pone.0295710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
Pannexins are ubiquitously expressed in human and mouse tissues. Pannexin 1 (Panx1), the most thoroughly characterized member of this family, forms plasmalemmal membrane channels permeable to relatively large molecules, such as ATP. Although human and mouse Panx1 amino acid sequences are conserved in the presently known regulatory sites involved in trafficking and modulation of the channel, differences are reported in the N- and C-termini of the protein, and the mechanisms of channel activation by different stimuli remain controversial. Here we used a neuroblastoma cell line to study the activation properties of endogenous mPanx1 and exogenously expressed hPanx1. Dye uptake and electrophysiological recordings revealed that in contrast to mouse Panx1, the human ortholog is insensitive to stimulation with high extracellular [K+] but responds similarly to activation of the purinergic P2X7 receptor. The two most frequent Panx1 polymorphisms found in the human population, Q5H (rs1138800) and E390D (rs74549886), exogenously expressed in Panx1-null N2a cells revealed that regarding P2X7 receptor mediated Panx1 activation, the Q5H mutant is a gain of function whereas the E390D mutant is a loss of function variant. Collectively, we demonstrate differences in the activation between human and mouse Panx1 orthologs and suggest that these differences may have translational implications for studies where Panx1 has been shown to have significant impact.
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Affiliation(s)
- Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Preeti Dohare
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - David C. Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Eliana Scemes
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
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Dou X, Ji W, Dai M, Sun S, Chen R, Yang J, Long J, Ge Y, Lin Y. Spatial and temporal mapping of neuron-microglia interaction modes in acute ischemic stroke. Biochem Pharmacol 2023; 216:115772. [PMID: 37659736 DOI: 10.1016/j.bcp.2023.115772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Ischemic stroke (IS) is a major cause of morbidity and mortality worldwide, accounting for 75-80% of all strokes. Under conditions of ischemia and hypoxia, neurons suffer damage or death, leading to a series of secondary immune reactions. Microglia, the earliest activated immune cells, can exert neurotoxic or neuroprotective effects on neurons through secretion of factors. There exists a complex interaction between neurons and microglia during this process. Moreover, the interaction between them becomes even more complex due to differences in the infarct area and reperfusion time. This review first elaborates on the differences in neuronal death modes between the ischemic core and penumbra, and then introduces the differences in microglial markers across different infarct areas with varying reperfusion time, indicating distinct functions. Finally, we focus on exploring the interaction modes between neurons and microglia in order to precisely target beneficial interactions and inhibit harmful ones, thus providing new therapeutic strategies for the treatment of IS.
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Affiliation(s)
- Xiaoke Dou
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China
| | - Wei Ji
- Department of Anesthesiology, Yantai Affiliated Hospital of BinZhou Medical College, Yantai 264000, China
| | - Maosha Dai
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China
| | - Shujun Sun
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China; Department of Pain, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Rui Chen
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China
| | - Juexi Yang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China
| | - Junhao Long
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China
| | - Yangyang Ge
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China.
| | - Yun Lin
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China.
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Guebel DV. Human hippocampal astrocytes: Computational dissection of their transcriptome, sexual differences and exosomes across ageing and mild-cognitive impairment. Eur J Neurosci 2023; 58:2677-2707. [PMID: 37427765 DOI: 10.1111/ejn.16081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 02/20/2023] [Accepted: 06/16/2023] [Indexed: 07/11/2023]
Abstract
The role of astrocytes in Alzheimer's disease is often disregarded. Hence, characterization of astrocytes along their early evolution toward Alzheimer would be greatly beneficial. However, due to their exquisite responsiveness, in vivo studies are difficult. So public microarray data of hippocampal homogenates from (healthy) young, (healthy) elder and elder with mild cognitive impairment (MCI) were subjected to re-analysis by a multi-step computational pipeline. Ontologies and pathway analyses were compared after determining the differential genes that, belonging to astrocytes, have splice forms. Likewise, the subset of molecules exportable to exosomes was also determined. The results showed that astrocyte's phenotypes changed significantly. While already 'activated' astrocytes were found in the younger group, major changes occurred during ageing (increased vascular remodelling and response to mechanical stimulus, diminished long-term potentiation and increased long-term depression). MCI's astrocytes showed some 'rejuvenated' features, but their sensitivity to shear stress was markedly lost. Importantly, most of the changes showed to be sex biassed. Men's astrocytes are enriched in a type 'endfeet-astrocytome', whereas women's astrocytes appear close to the 'scar-forming' type (prone to endothelial dysfunction, hypercholesterolemia, loss of glutamatergic synapses, Ca+2 dysregulation, hypoxia, oxidative stress and 'pro-coagulant' phenotype). In conclusion, the computational dissection of the networks based on the hippocampal gene isoforms provides a relevant proxy to in vivo astrocytes, also revealing the occurrence of sexual differences. Analyses of the astrocytic exosomes did not provide an acceptable approximation to the overall functioning of astrocytes in the hippocampus, probably due to the selective cellular mechanisms which charge the cargo molecules.
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