1
|
Hernandez-Espinosa DR, Gale JR, Scrabis MG, Aizenman E. Microglial reprogramming by Hv1 antagonism protects neurons from inflammatory and glutamate toxicity. J Neurochem 2023; 165:29-54. [PMID: 36625847 PMCID: PMC10106429 DOI: 10.1111/jnc.15760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/28/2022] [Accepted: 01/02/2023] [Indexed: 01/11/2023]
Abstract
Although the precise mechanisms determining the neurotoxic or neuroprotective activation phenotypes in microglia remain poorly characterized, metabolic changes in these cells appear critical for these processes. As cellular metabolism can be tightly regulated by changes in intracellular pH, we tested whether pharmacological targeting of the microglial voltage-gated proton channel 1 (Hv1), an important regulator of intracellular pH, is critical for activated microglial reprogramming. Using a mouse microglial cell line and mouse primary microglia cultures, either alone, or co-cultured with rat cerebrocortical neurons, we characterized in detail the microglial activation profile in the absence and presence of Hv1 inhibition. We observed that activated microglia neurotoxicity was mainly attributable to the release of tumor necrosis factor alpha, reactive oxygen species, and zinc. Strikingly, pharmacological inhibition of Hv1 largely abrogated inflammatory neurotoxicity not only by reducing the production of cytotoxic mediators but also by promoting neurotrophic molecule production and restraining excessive phagocytic activity. Importantly, the Hv1-sensitive change from a pro-inflammatory to a neuroprotective phenotype was associated with metabolic reprogramming, particularly via a boost in NADH availability and a reduction in lactate. Most critically, Hv1 antagonism not only reduced inflammatory neurotoxicity but also promoted microglia-dependent neuroprotection against a separate excitotoxic injury. Our results strongly suggest that Hv1 blockers may provide an important therapeutic tool against a wide range of inflammatory neurodegenerative disorders.
Collapse
Affiliation(s)
- Diego R Hernandez-Espinosa
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jenna R Gale
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Mia G Scrabis
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
2
|
P2X7 Is Involved in the Mouse Retinal Degeneration via the Coordinated Actions in Different Retinal Cell Types. Antioxidants (Basel) 2023; 12:antiox12010141. [PMID: 36671003 PMCID: PMC9854982 DOI: 10.3390/antiox12010141] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Adenosine triphosphate (ATP) released from dying cells with high concentrations is sensed as a danger signal by the P2X7 receptor. Sodium iodate (NaIO3) is an oxidative toxic agent, and its retinal toxicity has been used as the model of dry age-related macular degeneration (AMD). In this study, we used NaIO3-treated mice and cultured retinal cells, including BV-2 microglia, 661W photoreceptors, rMC1 Müller cells and ARPE-19 retinal epithelial cells, to understand the pathological action of P2X7 in retinal degeneration. We found that NaIO3 can significantly decrease the photoreceptor function by reducing a-wave and b-wave amplitudes in electroretinogram (ERG) analysis. Optical coherence tomography (OCT) analysis revealed the degeneration of retinal epithelium and ganglion cell layers. Interestingly, P2X7-/- mice were protected from the NaIO3-induced retinopathy and inflammatory NLRP3, IL-1β and IL-6 gene expression in the retina. Hematoxylin and eosin staining indicated that the retinal epithelium was less deteriorated in P2X7-/- mice compared to the WT group. Although P2X7 was barely detected in 661W, rMC1 and ARPE-19 cells, its gene and protein levels can be increased after NaIO3 treatment, leading to a synergistic cytotoxicity of BzATP [2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate tri(triethyleneammonium)salt] and NaIO3 administration in ARPE-19 cells. In conclusion, the paracrine action of the ATP/P2X7 axis via cell-cell communication is involved in NaIO3-induced retinal injury. Our results show that P2X7 antagonist might be a potential therapy in inflammation-related retinal degeneration.
Collapse
|
3
|
Mckenzie ADJ, Garrett TR, Werry EL, Kassiou M. Purinergic P2X 7 Receptor: A Therapeutic Target in Amyotrophic Lateral Sclerosis. ACS Chem Neurosci 2022; 13:1479-1490. [PMID: 35512313 DOI: 10.1021/acschemneuro.2c00133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by upper and lower motor neuron loss. The pathomechanisms of ALS are still poorly understood with current hypotheses involving genetic mutations, excitotoxicity, and reactive oxygen species formation. In the absence of a disease-altering clinically approved therapeutic, there is an ever-increasing need to identify new targets to develop drugs that delay disease onset and/or progression. The purinergic P2X7 receptor (P2X7R) has been implicated widely across the ALS realm, providing a potential therapeutic strategy. This review summarizes the current understanding of ALS, the P2X7R and its role in ALS, the current landscape of P2X7R antagonists, and the in vivo potential of these antagonists in preclinical ALS models.
Collapse
Affiliation(s)
- André D. J. Mckenzie
- School of Chemistry, Faculty of Science, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Taylor R. Garrett
- School of Chemistry, Faculty of Science, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Eryn L. Werry
- School of Chemistry, Faculty of Science, University of Sydney, Sydney, New South Wales 2006, Australia
- Central Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael Kassiou
- School of Chemistry, Faculty of Science, University of Sydney, Sydney, New South Wales 2006, Australia
| |
Collapse
|
4
|
Glial Purinergic Signaling-Mediated Oxidative Stress (GPOS) in Neuropsychiatric Disorders. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1075440. [PMID: 35281471 PMCID: PMC8916856 DOI: 10.1155/2022/1075440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/21/2022] [Accepted: 02/09/2022] [Indexed: 11/17/2022]
Abstract
Oxidative stress (OS) has been implicated in the progression of multiple neuropsychiatric disorders, including schizophrenia (SZ), major depressive disorder (MDD), bipolar disorder, and autism. However, whether glial purinergic signaling interaction with oxidative/antioxidative system displays an important role in neuropsychiatric disorders is still unclear. In this review, we firstly summarize the oxidative/antioxidative pathways shared in different glial cells and highlight the cell type-specific difference in response to OS. Then, we collect the evidence showing the regulation of purinergic signaling in OS with an emphasis on adenosine and its receptors, P2Y1 receptor in the P2Y family and P2X7receptor in the P2X family. Available data shows that the activation of P1 receptors and P2X accelerates the OS; reversely, the activation of the P2Y family (P2Y1) causes protective effect against OS. Finally, we discuss current findings demonstrating the contribution of the purinergic signaling system to neuropsychiatric disorders and point out the potential role of OS in this process to propose a “glial purinergic-oxidative stress” (“GPOS”) hypothesis for future development of therapeutic strategies against a variety of neuropsychiatric disorders.
Collapse
|
5
|
Fujishima A, Takahashi K, Goto M, Hirakawa T, Iwasawa T, Togashi K, Maeda E, Shirasawa H, Miura H, Sato W, Kumazawa Y, Terada Y. Live visualisation of electrolytes during mouse embryonic development using electrolyte indicators. PLoS One 2021; 16:e0246337. [PMID: 33513193 PMCID: PMC7845971 DOI: 10.1371/journal.pone.0246337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/18/2021] [Indexed: 11/27/2022] Open
Abstract
Studies have shown that some electrolytes, including Na+ and K+, play important roles in embryonic development. However, these studies evaluated these electrolytes by using inhibitors or knockout mice, with no mention on the changes in the intracellular electrolyte concentrations during embryogenesis. In this study, we used the electrolyte indicators CoroNa Green AM and ION Potassium Green-2 AM to directly visualise intracellular concentrations of Na+ and K+, respectively, at each embryonic developmental stage in mouse embryos. We directly observed intracellular electrolyte concentrations at the morula, blastocyst, and hatching stages. Our results revealed dynamic changes in intracellular electrolyte concentrations; we found that the intracellular Na+ concentration decreased, while K+ concentration increased during blastocoel formation. The degree of change in intensity in response to ouabain, an inhibitor of Na+/K+ ATPase, was considered to correspond to the degree of Na+/K+ ATPase activity at each developmental stage. Additionally, after the blastocyst stage, trophectoderm cells in direct contact with the blastocoel showed higher K+ concentrations than in direct contact with inner cell mass, indicating that Na+/K+ ATPase activity differs depending on the location in the trophectoderm. This is the first study to use CoroNa Green AM and ION Potassium Green-2 AM in mouse embryos and visualise electrolytes during embryonic development. The changes in electrolyte concentration observed in this study were consistent with the activity of Na+/K+ ATPase reported previously, and it was possible to image more detailed electrolyte behaviour in embryo cells. This method can be used to improve the understanding of cell physiology and is useful for future embryonic development studies.
Collapse
Affiliation(s)
- Akiko Fujishima
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Kazumasa Takahashi
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Mayumi Goto
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Takeo Hirakawa
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Takuya Iwasawa
- Department of Obstetrics and Gynecology, Omagari Kousei Medical Center, Akita, Japan
| | - Kazue Togashi
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Eri Maeda
- Department of Environmental Health Science and Public Health, Akita University Graduate School of Medicine, Akita, Japan
| | - Hiromitsu Shirasawa
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Hiroshi Miura
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Wataru Sato
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Yukiyo Kumazawa
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| | - Yukihiro Terada
- Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan
| |
Collapse
|
6
|
Savage JC, Shinde P, Yao Y, Davare MA, Shinde U. A Broccoli aptamer chimera yields a fluorescent K + sensor spanning physiological concentrations. Chem Commun (Camb) 2021; 57:1344-1347. [PMID: 33432937 DOI: 10.1039/d0cc07042d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The RNA aptamer Broccoli accepts 2'fluorinated (2'F) pyrimidine nucleotide incorporation without perturbation of structure or fluorescence in the presence of potassium and DFHBI. However, the modification decreases Broccoli's apparent affinity for K+ >30-fold. A chimera of Broccoli RNAs with mixed chemistries displays linear fluorescent gain spanning physiological K+ concentrations, yielding an effective RNA-based fluorescent K+ sensor.
Collapse
Affiliation(s)
- Jonathan C Savage
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA.
| | | | | | | | | |
Collapse
|
7
|
Pethő Z, Najder K, Carvalho T, McMorrow R, Todesca LM, Rugi M, Bulk E, Chan A, Löwik CWGM, Reshkin SJ, Schwab A. pH-Channeling in Cancer: How pH-Dependence of Cation Channels Shapes Cancer Pathophysiology. Cancers (Basel) 2020; 12:E2484. [PMID: 32887220 PMCID: PMC7565548 DOI: 10.3390/cancers12092484] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022] Open
Abstract
Tissue acidosis plays a pivotal role in tumor progression: in particular, interstitial acidosis promotes tumor cell invasion, and is a major contributor to the dysregulation of tumor immunity and tumor stromal cells. The cell membrane and integral membrane proteins commonly act as important sensors and transducers of altered pH. Cell adhesion molecules and cation channels are prominent membrane proteins, the majority of which is regulated by protons. The pathophysiological consequences of proton-sensitive ion channel function in cancer, however, are scarcely considered in the literature. Thus, the main focus of this review is to highlight possible events in tumor progression and tumor immunity where the pH sensitivity of cation channels could be of great importance.
Collapse
Affiliation(s)
- Zoltán Pethő
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Karolina Najder
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Tiago Carvalho
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Roisin McMorrow
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
| | - Luca Matteo Todesca
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Micol Rugi
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Etmar Bulk
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Alan Chan
- Percuros B.V., 2333 CL Leiden, The Netherlands;
| | - Clemens W. G. M. Löwik
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
- Department of Oncology CHUV, UNIL and Ludwig Cancer Center, 1011 Lausanne, Switzerland
| | - Stephan J. Reshkin
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Albrecht Schwab
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| |
Collapse
|
8
|
Liu C, Ma H, Slitt AL, Seeram NP. Inhibitory Effect of Cannabidiol on the Activation of NLRP3 Inflammasome Is Associated with Its Modulation of the P2X7 Receptor in Human Monocytes. JOURNAL OF NATURAL PRODUCTS 2020; 83:2025-2029. [PMID: 32374168 DOI: 10.1021/acs.jnatprod.0c00138] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cannabidiol (CBD), a phytocannabinoid, has been reported to have anti-inflammatory effects associated with NLRP3 inflammasome activation, but its mechanism of anti-inflammasome action remains unclear. Herein, we report CBD's effect on NLRP3 inflammasome activation and its modulation of P2X7, an inflammasome activation-related receptor, in human THP-1 monocytes. CBD (0.1, 1, and 10 μM) exerted anti-inflammasome activity in LPS-nigericin-stimulated THP-1 monocytes by reducing media IL-1β concentration (by 63.9%, 64.1%, and 83.1%, respectively), which was similar to the known NLRP3 inflammasome inhibitors oridonin and MCC950 (16.9% vs 20.8% and 17.4%, respectively; at 10 μM). CBD (10 μM) decreased nigericin-alone- and nigericin-lipopolysaccharide-induced potassium efflux by 13.7% and 13.0%, respectively, in THP-1 monocytes, strongly suggesting P2X7 receptor modulation. Computational docking data supported the potential for CBD binding to the P2X7 receptor via interaction with GLU 172 and VAL 173 residues. Overall, the observed CBD suppressive effect on NLRP3 inflammasome activation in THP-1 monocytes was associated with decreased potassium efflux, as well as in silico prediction of P2X7 receptor binding. CBD inhibitory effects on the NLRP3 inflammasome may contribute to the overall anti-inflammatory effects reported for this phytocannabinoid.
Collapse
Affiliation(s)
- Chang Liu
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Hang Ma
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Angela L Slitt
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Navindra P Seeram
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| |
Collapse
|
9
|
Liu Y, Wu Y, Gu S, Yin Q, Li H, Wang J, Geng D, Xu Y. The P2X7 receptor (P2X7R)-specific antagonist A804598 inhibits inflammatory reaction in human fibroblast-like synoviocytes. Am J Transl Res 2020; 12:45-53. [PMID: 32051736 PMCID: PMC7013224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/15/2019] [Indexed: 06/10/2023]
Abstract
Activation of the P2X7 receptor (P2X7R) has been found to increase expression of tumor necrosis factor-α (TNF-α) in the joints and synovial lining of patients with rheumatoid arthritis (RA). Increased expression of TNF-α promotes joint destruction through deterioration of type II collagen by matrix metalloproteinases (MMPs), expression of proinflammatory cytokines, oxidative stress, and activation of cellular signaling pathways. In the present study, we exposed fibroblast-like synoviocytes (FLSs) to TNF-α in the presence and absence of the P2X7R antagonist A804598. We then employed real time PCR and western blot analysis to analyze the mRNA and protein expression levels of P2X7R in both control and RA-FLSs. We confirmed that P2X7R is expressed on FLSs and is upregulated in RA-FLSs and FLSs exposed to TNF-α. Importantly, we also demonstrate the ability of P2X7R antagonism using A804598 to suppress oxidative stress, expression of interleukin (IL)-1β, IL-6, MMP-1, MMP-3, MMP-13 as well as activation of the Janus family of tyrosine kinase/signal transducer and activator of transcription (JAK1/STAT3) proinflammatory signaling pathway. These findings implicate a novel role of antagonism of P2X7R as a target for the treatment and prevention of RA.
Collapse
Affiliation(s)
- Yu Liu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow UniversitySuzhou 215006, Jiangsu, China
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Yongwei Wu
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Sanjun Gu
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Qudong Yin
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Haifeng Li
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Jian Wang
- Department of Orthopaedics, Wuxi No. 9 People’s Hospital Affiliated to Soochow UniversityWuxi 214062, Jiangsu, China
| | - Dechun Geng
- Department of Orthopaedics, The First Affiliated Hospital of Soochow UniversitySuzhou 215006, Jiangsu, China
| | - Yaozeng Xu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow UniversitySuzhou 215006, Jiangsu, China
| |
Collapse
|
10
|
Sekar P, Huang DY, Hsieh SL, Chang SF, Lin WW. AMPK-dependent and independent actions of P2X7 in regulation of mitochondrial and lysosomal functions in microglia. Cell Commun Signal 2018; 16:83. [PMID: 30458799 PMCID: PMC6245559 DOI: 10.1186/s12964-018-0293-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/01/2018] [Indexed: 12/24/2022] Open
Abstract
Background P2X7 is ubiquitously expressed in myeloid cells and regulates the pathophysiology of inflammatory diseases. Since mitochondrial function in microglia is highly associated with microglial functions in controlling neuronal plasticity and brain homeostasis, we interested to explore the roles of P2X7 in mitochondrial and lysosomal functions as well as mitophagy in microglia. Methods P2X7−/− bone marrow-derived macrophages (BMDM), primary microglia and BV-2 immortalized microglial cells were used to detect the particular protein expression by immunoblotting. Mitochondrial reactive oxygen species (mitoROS), intracellular calcium, mitochondrial mass and lysosomal integrity were examined by flow cytometry. Mitochondrial oxygen consumption rate (OCR) was recorded using Seahorse XF flux analyzer. Confocal microscopic images were performed to indicate the mitochondrial dynamics and mitophagy after P2X7 activation. Results In primary microglia, BV-2 microglial cells and BMDM, P2X7 agonist BzATP triggered AMPK activation and LC3II accumulation through reactive oxygen species (ROS) and CaMKKII pathways, and these effects were abolished by P2X7 antagonist A438079 and P2X7 deficiency. Moreover, we detected the dramatic decreases of mitochondrial OCR and mass following P2X7 activation. AMPK inhibition by compound C or AMPK silencing reversed the P2X7 actions in reduction of mitochondrial mass, induction of mitochondrial fission and mitophagy, but not in uncoupling of mitochondrial respiration. Interestingly, we found that P2X7 activation induced nuclear translocation of TFEB via an AMPK-dependent pathway and led to lysosomal biogenesis. Mimicking the actions of BzATP, nigericin also induced ROS-dependent AMPK activation, mitophagy, mitochondrial fission and respiratory inhibition. Longer exposure of BzATP induced cell death, and this effect was accompanied by the lysosomal instability and was inhibited by autophagy and cathepsin B inhibitors. Conclusion Altogether ROS- and CaMKK-dependent AMPK activation is involved in P2X7-mediated mitophagy, mitochondrial dynamics and lysosomal biogenesis in microglial cells, which is followed by cytotoxicity partially resulting from mitophagy and cathepsin B activation. Electronic supplementary material The online version of this article (10.1186/s12964-018-0293-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ponarulselvam Sekar
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Duen-Yi Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | | | - Shwu-Fen Chang
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Wan-Wan Lin
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan. .,Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
| |
Collapse
|
11
|
Dunton CL, Purves JT, Hughes FM, Jin H, Nagatomi J. Elevated hydrostatic pressure stimulates ATP release which mediates activation of the NLRP3 inflammasome via P2X 4 in rat urothelial cells. Int Urol Nephrol 2018; 50:1607-1617. [PMID: 30099658 PMCID: PMC6129973 DOI: 10.1007/s11255-018-1948-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/30/2018] [Indexed: 02/06/2023]
Abstract
Partial bladder outlet obstruction (pBOO) is a prevalent urological condition commonly accompanied by increased intravesical pressure, inflammation, and fibrosis. Studies have demonstrated that pBOO results in increased NLRP3 inflammasome and caspase-1 activation and that ATP is released from urothelial cells in response to elevated pressure. In the present study, we investigated the role of elevated pressure in triggering caspase-1 activation via purinergic receptors activation in urothelial cells. Rat urothelial cell line, MYP3 cells, was subjected to hydrostatic pressures of 15 cmH2O for 60 min, or 40 cmH2O for 1 min to simulate elevated storage and voiding pressure conditions, respectively. ATP concentration in the supernatant media and intracellular caspase-1 activity in cell lysates were measured. Pressure experiments were repeated in the presence of antagonists for purinergic receptors to determine the mechanism for pressure-induced caspase-1 activation. Exposure of MYP3 cells to both pressure conditions resulted in an increase in extracellular ATP levels and intracellular caspase-1 activity. Treatment with P2X7 antagonist led to a decrease in pressure-induced ATP release by MYP3 cells, while P2X4 antagonist had no effect but both antagonists inhibited pressure-induced caspase-1 activation. Moreover, when MYP3 cells were treated with extracellular ATP (500 µM), P2X4 antagonist inhibited ATP-induced caspase-1 activation, but not P2X7 antagonist. We concluded that pressure-induced extracellular ATP in urothelial cells is amplified by P2X7 receptor activation and ATP-induced-ATP release. The amplified ATP signal then activates P2X4 receptors, which mediate activation of the caspase-1 inflammatory response.
Collapse
Affiliation(s)
- Cody L Dunton
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - J Todd Purves
- Department of Bioengineering, Clemson University, Clemson, SC, USA.,Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA.,Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Francis M Hughes
- Department of Bioengineering, Clemson University, Clemson, SC, USA.,Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Huixia Jin
- Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Jiro Nagatomi
- Department of Bioengineering, Clemson University, Clemson, SC, USA.
| |
Collapse
|
12
|
The Mycobacterial Adjuvant Analogue TDB Attenuates Neuroinflammation via Mincle-Independent PLC-γ1/PKC/ERK Signaling and Microglial Polarization. Mol Neurobiol 2018; 56:1167-1187. [PMID: 29876879 DOI: 10.1007/s12035-018-1135-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/18/2018] [Indexed: 02/06/2023]
Abstract
Microglial activation has long been recognized as a hallmark of neuroinflammation. Recently, the bacillus Calmette-Guerin (BCG) vaccine has been reported to exert neuroprotective effects against several neurodegenerative disorders. Trehalose-6,6'-dibehenate (TDB) is a synthetic analogue of trehalose-6,6'-dimycolate (TDM, also known as the mycobacterial cord factor) and is a new adjuvant of tuberculosis subunit vaccine currently in clinical trials. Both TDM and TDB can activate macrophages and dendritic cells through binding to C-type lectin receptor Mincle; however, its action mechanism in microglia and their relationship with neuroinflammation are still unknown. In this article, we found that TDB inhibited LPS-induced M1 microglial polarization in primary microglia and BV-2 cells. However, TDB itself had no effects on IKK, p38, and JNK activities or cytokine expression. In contrast, TDB activated ERK1/2 through PLC-γ1/PKC signaling and in turn decreased LPS-induced NF-κB nuclear translocation. Furthermore, TDB-induced AMPK activation via PLC-γ1/calcium/CaMKKβ-dependent pathway and thereby enhanced M2 gene expressions. Interestingly, knocking out Mincle did not alter the anti-inflammatory and M2 polarization effects of TDB in microglia. Conditional media from LPS-stimulated microglial cells can induce in vitro neurotoxicity, and this action was attenuated by TDB. Using a mouse neuroinflammation model, we found that TDB suppressed LPS-induced M1 microglial activation and sickness behavior, but promoted M2 microglial polarization in both WT and Mincle-/- mice. Taken together, our results suggest that TDB can act independently of Mincle to inhibit LPS-induced inflammatory response through PLC-γ1/PKC/ERK signaling and promote microglial polarization towards M2 phenotype via PLC-γ1/calcium/CaMKKβ/AMPK pathway. Thus, TDB may be a promising therapeutic agent for the treatment of neuroinflammatory diseases.
Collapse
|