1
|
Chen X, Sun X, Ge Y, Zhou X, Chen JF. Targeting adenosine A 2A receptors for early intervention of retinopathy of prematurity. Purinergic Signal 2024:10.1007/s11302-024-09986-x. [PMID: 38329708 DOI: 10.1007/s11302-024-09986-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/16/2024] [Indexed: 02/09/2024] Open
Abstract
Retinopathy of prematurity (ROP) continues to pose a significant threat to the vision of numerous children worldwide, primarily owing to the increased survival rates of premature infants. The pathologies of ROP are mainly linked to impaired vascularization as a result of hyperoxia, leading to subsequent neovascularization. Existing treatments, including anti-vascular endothelial growth factor (VEGF) therapies, have thus far been limited to addressing pathological angiogenesis at advanced ROP stages, inevitably leading to adverse side effects. Intervention to promote physiological angiogenesis during the initial stages could hold the potential to prevent ROP. Adenosine A2A receptors (A2AR) have been identified in various ocular cell types, exhibiting distinct densities and functionally intricate connections with oxygen metabolism. In this review, we discuss experimental evidence that strongly underscores the pivotal role of A2AR in ROP. In particular, A2AR blockade may represent an effective treatment strategy, mitigating retinal vascular loss by reversing hyperoxia-mediated cellular proliferation inhibition and curtailing hypoxia-mediated neovascularization in oxygen-induced retinopathy (OIR). These effects stem from the interplay of endothelium, neuronal and glial cells, and novel molecular pathways (notably promoting TGF-β signaling) at the hyperoxia phase. We propose that pharmacological targeting of A2AR signaling may confer an early intervention for ROP with distinct therapeutic benefits and mechanisms than the anti-VEGF therapy.
Collapse
Affiliation(s)
- Xuhao Chen
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Xiaoting Sun
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yuanyuan Ge
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Xuzhao Zhou
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China.
| | - Jiang-Fan Chen
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China.
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou, China.
| |
Collapse
|
2
|
Shi M, Cao L, Ding D, Yu W, Lv P, Yu N. Effects of Noise Damage on the Purinergic Signal of Cochlear Spiral Ganglion Cells in Guinea Pigs. Mol Biotechnol 2024; 66:321-331. [PMID: 37145220 DOI: 10.1007/s12033-023-00755-6] [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: 10/30/2022] [Accepted: 04/16/2023] [Indexed: 05/06/2023]
Abstract
To observe the expression changes of P2 protein in cochlear spiral ganglion cells before and after noise injury, and to explore the relationship between the changes of purinergic receptors in spiral ganglion cells and noise-induced hearing loss, so that the signal transduction of purinergic receptors can be used to treat SNHL The target point provides a theoretical basis. The experimental animals were randomly divided into normal and experimental groups. The experimental group was given 120 dB white noise continuous exposure for 10 days and 3 h a day. The auditory brainstem response was measured before and after the noise exposure. After the noise exposure, the two groups of animals were collected. Do immunofluorescence staining, western blot, fluorescence real-time quantitative PCR to observe the expression of P2 protein. The average hearing threshold of the animals in the experimental group increased to 38.75 ± 6.44 dB SPL after 7 days of noise exposure, and the high-frequency hearing loss was lower and severe; the average hearing threshold increased to 54.38 ± 6.80 dB SPL after 10 days of noise exposure, and the hearing loss at 4 k Hz was relatively high. Light; Frozen sections of cochlear spiral ganglion cells and staining of isolated spiral ganglion cells found that P2X2, P2X3, P2X4, P2X7, P2Y2, and P2Y4 proteins were all expressed in cochlear spiral ganglion cells before noise exposure. Among them, P2X3 expression increased and P2X4, the down-regulation of P2Y2 expression was statistically significant (P < 0.05); Western blot and real-time quantitative PCR detection results showed that the expression of P2X3 was significantly increased after noise exposure than before noise exposure (P < 0.05), and P2X4 and P2Y2 were expressed after noise exposure The amount was significantly lower than before noise exposure (P < 0.05). (Figure. 4). After noise exposure, the expression of P2 protein is upregulated or downregulated. By affecting the Ca2+ cycle, the transmission of sound signals to the auditory center is blocked, which provides a theoretical basis for the signal transduction of purinergic receptors to become a target for the treatment of SNHL.
Collapse
Affiliation(s)
- Min Shi
- Suining Central Hospital, Suining, 629000, China
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, Beijing, 100000, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, 100000, China
- State Key Lab of Hearing Science, Ministry of Education, Beijing, 100000, China
- Beijing Key Lab of Hearing Impairment Prevention and Treatment, Beijing, 100000, China
| | - Lei Cao
- Suining Central Hospital, Suining, 629000, China
| | - Daxiong Ding
- Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, China
| | - Wenxing Yu
- Suining Central Hospital, Suining, 629000, China
| | - Ping Lv
- Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, China
| | - Ning Yu
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, Beijing, 100000, China.
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, 100000, China.
- State Key Lab of Hearing Science, Ministry of Education, Beijing, 100000, China.
- Beijing Key Lab of Hearing Impairment Prevention and Treatment, Beijing, 100000, China.
| |
Collapse
|
3
|
Yang Y, Murtha K, Climer LK, Ceriani F, Thompson P, Hornak AJ, Marcotti W, Simmons DD. Oncomodulin regulates spontaneous calcium signalling and maturation of afferent innervation in cochlear outer hair cells. J Physiol 2023; 601:4291-4308. [PMID: 37642186 PMCID: PMC10621907 DOI: 10.1113/jp284690] [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: 03/14/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
Cochlear outer hair cells (OHCs) are responsible for the exquisite frequency selectivity and sensitivity of mammalian hearing. During development, the maturation of OHC afferent connectivity is refined by coordinated spontaneous Ca2+ activity in both sensory and non-sensory cells. Calcium signalling in neonatal OHCs can be modulated by oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein. Here, we investigated whether OCM regulates OHC spontaneous Ca2+ activity and afferent connectivity during development. Using a genetically encoded Ca2+ sensor (GCaMP6s) expressed in OHCs in wild-type (Ocm+/+ ) and Ocm knockout (Ocm-/- ) littermates, we found increased spontaneous Ca2+ activity and upregulation of purinergic receptors in OHCs from Ocm-/- cochlea immediately following birth. The afferent synaptic maturation of OHCs was delayed in the absence of OCM, leading to an increased number of ribbon synapses and afferent fibres on Ocm-/- OHCs before hearing onset. We propose that OCM regulates the spontaneous Ca2+ signalling in the developing cochlea and the maturation of OHC afferent innervation. KEY POINTS: Cochlear outer hair cells (OHCs) exhibit spontaneous Ca2+ activity during a narrow period of neonatal development. OHC afferent maturation and connectivity requires spontaneous Ca2+ activity. Oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein, modulates Ca2+ signals in immature OHCs. Using transgenic mice that endogenously expressed a Ca2+ sensor, GCaMP6s, we found increased spontaneous Ca2+ activity and upregulated purinergic receptors in Ocm-/- OHCs. The maturation of afferent synapses in Ocm-/- OHCs was also delayed, leading to an upregulation of ribbon synapses and afferent fibres in Ocm-/- OHCs before hearing onset. We propose that OCM plays an important role in modulating Ca2+ activity, expression of Ca2+ channels and afferent innervation in developing OHCs.
Collapse
Affiliation(s)
- Yang Yang
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Kaitlin Murtha
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Leslie K. Climer
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Federico Ceriani
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Pierce Thompson
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Aubrey J. Hornak
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Dwayne D. Simmons
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
| |
Collapse
|
4
|
Yang Y, Murtha K, Climer LK, Ceriani F, Thompson P, Hornak AJ, Marcotti W, Simmons DD. Oncomodulin Regulates Spontaneous Calcium Signaling and Maturation of Afferent Innervation in Cochlear Outer Hair Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.529895. [PMID: 36909575 PMCID: PMC10002690 DOI: 10.1101/2023.03.01.529895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Cochlear outer hair cells (OHCs) are responsible for the exquisite frequency selectivity and sensitivity of mammalian hearing. During development, the maturation of OHC afferent connectivity is refined by coordinated spontaneous Ca 2+ activity in both sensory and non-sensory cells. Calcium signaling in neonatal OHCs can be modulated by Oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein. Here, we investigated whether OCM regulates OHC spontaneous Ca 2+ activity and afferent connectivity during development. Using a genetically encoded Ca 2+ sensor (GCaMP6s) expressed in OHCs in wild-type (Ocm +/+ ) and Ocm knockout (Ocm -/- ) littermates, we found increased spontaneous Ca 2+ activity and upregulation of purinergic receptors in OHCs from GCaMP6s Ocm -/- cochlea immediately following birth. The afferent synaptic maturation of OHCs was delayed in the absence of OCM, leading to an increased number of ribbon synapses and afferent fibers on GCaMP6s Ocm -/- OHCs before hearing onset. We propose that OCM regulates the spontaneous Ca 2+ signaling in the developing cochlea and the maturation of OHC afferent innervation.
Collapse
|
5
|
Vlajkovic SM, Thorne PR. Purinergic Signalling in the Cochlea. Int J Mol Sci 2022; 23:ijms232314874. [PMID: 36499200 PMCID: PMC9741428 DOI: 10.3390/ijms232314874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
The mammalian cochlea is the sensory organ of hearing with a delicate, highly organised structure that supports unique operating mechanisms. ATP release from the secretory tissues of the cochlear lateral wall (stria vascularis) triggers numerous physiological responses by activating P2 receptors in sensory, supporting and neural tissues. Two families of P2 receptors, ATP-gated ion channels (P2X receptors) and G protein-coupled P2Y receptors, activate intracellular signalling pathways that regulate cochlear development, homeostasis, sensory transduction, auditory neurotransmission and response to stress. Of particular interest is a purinergic hearing adaptation, which reflects the critical role of the P2X2 receptor in adaptive cochlear response to elevated sound levels. Other P2 receptors are involved in the maturation of neural processes and frequency selectivity refinement in the developing cochlea. Extracellular ATP signalling is regulated by a family of surface-located enzymes collectively known as "ectonucleotidases" that hydrolyse ATP to adenosine. Adenosine is a constitutive cell metabolite with an established role in tissue protection and regeneration. The differential activation of A1 and A2A adenosine receptors defines the cochlear response to injury caused by oxidative stress, inflammation, and activation of apoptotic pathways. A1 receptor agonism, A2A receptor antagonism, and increasing adenosine levels in cochlear fluids all represent promising therapeutic tools for cochlear rescue from injury and prevention of hearing loss.
Collapse
Affiliation(s)
- Srdjan M. Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Correspondence: ; Tel.: +64-9-9239782
| | - Peter R. Thorne
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Section of Audiology, School of Population Health, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| |
Collapse
|
6
|
Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
|
7
|
Soliño M, Larrayoz IM, López EM, Rey-Funes M, Bareiro M, Loidl CF, Girardi E, Martínez A, López-Costa JJ. Adenosine A2A Receptor: A New Neuroprotective Target in Light-Induced Retinal Degeneration. Front Pharmacol 2022; 13:840134. [PMID: 35387355 PMCID: PMC8977837 DOI: 10.3389/fphar.2022.840134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/14/2022] [Indexed: 11/24/2022] Open
Abstract
Continuous illumination induces the degeneration of photoreceptors. This animal model of light-induced retinal degeneration resembles many characteristics of human degenerative diseases of the outer retina, such as age-related macular degeneration. This work aimed to evaluate the potential neuroprotective effect of the modulation of adenosine A2A receptor in the model of light-induced retinal degeneration. Sprague-Dawley rats were intravitreally injected in the right eye with either CGS 21680, an adenosine A2A receptor agonist, or SCH 58261, an adenosine A2A receptor antagonist. Contralateral eyes were injected with respective vehicles as control. Then, rats were subjected to continuous illumination (12,000 lux) for 24 h. Retinas were processed by glial fibrillary acidic protein (GFAP) immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) technique, Western blotting (WB), and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Another group of rats was subjected to functional studies by electroretinography. Animals treated with CGS21680 showed a significant increase of apoptotic nuclei in the outer nuclear layer and a significant increase of GFAP immunoreactive area of the retinas but did not alter WB nor electroretinography results. qRT-PCR showed that CGS 21680 significantly increased the expression of interleukin-1β. On the opposite, SCH 58261 significantly decreased apoptotic nuclei in the outer nuclear layer and GFAP immunoreactive area of the retinas. It also significantly decreased GFAP and activated caspase-3 levels as measured by WB and preserved retinal function, as treated eyes showed significantly greater amplitudes of a- and b-waves and oscillatory potentials. qRT-PCR revealed that SCH 58261 significantly decreased the expression of tumor necrosis factor-α. These results show that the blockade of the A2A receptor before the start of the pathogenic process is neuroprotective, as it prevents light-induced retinal damage. The use of A2A receptor antagonists deserves to be evaluated in retinal degenerative diseases.
Collapse
Affiliation(s)
- Manuel Soliño
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Ignacio M Larrayoz
- Biomarkers and Molecular Signaling Group, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Ester María López
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Manuel Rey-Funes
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Mariana Bareiro
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Cesar Fabián Loidl
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Elena Girardi
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Alfredo Martínez
- Angiogenesis Study Group, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Juan José López-Costa
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| |
Collapse
|
8
|
Kim SH, Choi JY. Purinergic signaling in the peripheral vestibular system. Purinergic Signal 2022; 18:165-176. [PMID: 35344126 DOI: 10.1007/s11302-022-09855-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/19/2022] [Indexed: 11/25/2022] Open
Abstract
The inner ear comprises the cochlea and vestibular system, which detect sound and acceleration stimulation, respectively. The function of the inner ear is regulated by ion transport activity among sensory epithelial cells, neuronal cells, non-sensory epithelial cells, and luminal fluid with a unique ionic composition of high [K+] and low [Na+], which enables normal hearing and balance maintenance. One of the important mechanisms regulating ion transport in the inner ear is purinergic signaling. Various purinergic receptors are distributed throughout inner ear epithelial cells and neuronal cells. To date, most studies have focused on the role of purinergic receptors in the cochlea, and few studies have examined these receptors in the vestibular system. As purinergic receptors play an important role in the cochlea, they would likely do the same in the vestibular system, which is fairly similar to the cochlea in cellular structure and function. Based on available studies performed to date, purinergic signaling is postulated to be involved in the regulation of ion homeostasis, protection of hair cells, otoconia formation, and regulation of electrical signaling from the sensory epithelium to vestibular neurons. In this review, the distribution and roles of purinergic receptors in the peripheral vestibular system are summarized and discussed.
Collapse
Affiliation(s)
- Sung Huhn Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea.
| |
Collapse
|
9
|
Identification of a Novel Stop Loss Mutation in P2RX2 Gene in an Iranian Family with Autosomal Nonsyndromic Hearing Loss. IRANIAN BIOMEDICAL JOURNAL 2021; 25:368-73. [PMID: 34425661 PMCID: PMC8487680 DOI: 10.52547/ibj.25.5.368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background: Hearing loss, a congenital genetic disorder in human, is difficult to diagnose. WES is a powerful approach for ethiological disgnosis of such disorders. Methods: One Iranian family with two patients were attented in the study. Sequencing of known NSHL genes was carried out to recognize the genetic causes of HL. Results: Molecular analyses identified a novel stop loss mutation, c.1048T>G (p.Term350Glu), whitin the P2RX2 gene, causing a termination-site modification.This event would lead to continued translation into the 3' UTR of the gene, which in turn may result in a longer protein product. The mutation was segregating with the disease phenotype and predicted to be pathogenic by bioinformatic tools. Conclusion: This study is the first Iranian case report of a diagnosis of ADNSHL caused by P2RX2 mutation. The recognition of other causative mutations in P2RX2 gene more supports the probable function of this gene in causing ADNSHL.
Collapse
|
10
|
Klose E, Kuhrt H, Kohen L, Wiedemann P, Bringmann A, Hollborn M. Hypoxic and osmotic expression of Kir2.1 potassium channels in retinal pigment epithelial cells: Contribution to vascular endothelial growth factor expression. Exp Eye Res 2021; 211:108741. [PMID: 34425102 DOI: 10.1016/j.exer.2021.108741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/22/2021] [Accepted: 08/19/2021] [Indexed: 12/31/2022]
Abstract
Retinal pigment epithelial (RPE) cells express different subtypes of inwardly rectifying potassium (Kir) channels. We investigated whether human and rat RPE cells express genes of strongly rectifying Kir2 channels. We also determined the hypoxic and hyperosmotic regulation of Kir2.1 gene expression in cultured human RPE cells and the effects of siRNA-mediated knockdown of Kir2.1 on VEGFA expression, VEGF secretion, proliferation, and viability of the cells. Extracellular hyperosmolarity was induced by addition of NaCl or sucrose. Hypoxia and chemical hypoxia were produced by cell culture in 0.25% O2 and addition of CoCl2, respectively. Gene expression levels were evaluated by real-time RT-PCR. Rat RPE cells contained Kir2.1, Kir2.2, Kir2.3, and Kir2.4 gene transcripts while human RPE cells contained Kir2.1, Kir2.2, and Kir2.4 transcripts. Immunocytochemical data may suggest that Kir2.1 protein in cultured human cells is expressed in both perinuclear and plasma membranes. Kir2.1 gene expression and Kir2.1 protein level in human cells increased under hypoxic and hyperosmotic conditions. The expression of the Kir2.1 gene was mediated in part by diverse intracellular signal transduction pathways and transcription factor activities under both conditions; the hyperosmotic, but not the CoCl2-induced Kir2.1 gene expression was dependent on intracellular calcium signaling. Autocrine/paracrine activation of purinergic receptors contributed to Kir2.1 gene expression under hyperosmotic (P2Y1, P2Y2, P2X7) and CoCl2-induced conditions (P2Y2, P2X7). Exogenous VEGF, TGF-β1, and blood serum decreased Kir2.1 gene expression. Inhibition of VEGF receptor-2 increased the Kir2.1 gene expression under control conditions and in CoCl2-simulated hypoxia, and decreased it under high NaCl conditions. Knockdown of Kir2.1 by siRNA inhibited the CoCl2-induced and hyperosmotic transcription of the VEGFA gene and caused a delayed decrease of the constitutive VEGFA gene expression while VEGF protein secretion was not altered. Kir2.1 knockdown stimulated RPE cell proliferation under control and hyperosmotic conditions without affecting cell viability. The data indicate that Kir2.1 channel activity is required for the expression of the VEGFA gene and inhibits the proliferation of RPE cells. Under control and hypoxic conditions, the extracellular VEGF level may regulate the production of VEGF via its inhibitory effect on the Kir2.1 gene transcription; this feedback loop may prevent overproduction of VEGF.
Collapse
Affiliation(s)
- Eva Klose
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, University of Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany; Helios Klinikum Aue, Aue, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany.
| |
Collapse
|
11
|
Harsing LG, Szénási G, Zelles T, Köles L. Purinergic-Glycinergic Interaction in Neurodegenerative and Neuroinflammatory Disorders of the Retina. Int J Mol Sci 2021; 22:ijms22126209. [PMID: 34201404 PMCID: PMC8228622 DOI: 10.3390/ijms22126209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 12/26/2022] Open
Abstract
Neurodegenerative–neuroinflammatory disorders of the retina seriously hamper human vision. In searching for key factors that contribute to the development of these pathologies, we considered potential interactions among purinergic neuromodulation, glycinergic neurotransmission, and microglia activity in the retina. Energy deprivation at cellular levels is mainly due to impaired blood circulation leading to increased release of ATP and adenosine as well as glutamate and glycine. Interactions between these modulators and neurotransmitters are manifold. First, P2Y purinoceptor agonists facilitate reuptake of glycine by glycine transporter 1, while its inhibitors reduce reverse-mode operation; these events may lower extracellular glycine levels. The consequential changes in extracellular glycine concentration can lead to parallel changes in the activity of NR1/NR2B type NMDA receptors of which glycine is a mandatory agonist, and thereby may reduce neurodegenerative events in the retina. Second, P2Y purinoceptor agonists and glycine transporter 1 inhibitors may indirectly inhibit microglia activity by decreasing neuronal or glial glycine release in energy-compromised retina. These inhibitions may have a role in microglia activation, which is present during development and progression of neurodegenerative disorders such as glaucomatous and diabetic retinopathies and age-related macular degeneration or loss of retinal neurons caused by thromboembolic events. We have hypothesized that glycine transporter 1 inhibitors and P2Y purinoceptor agonists may have therapeutic importance in neurodegenerative–neuroinflammatory disorders of the retina by decreasing NR1/NR2B NMDA receptor activity and production and release of a series of proinflammatory cytokines from microglial cells.
Collapse
Affiliation(s)
- Laszlo G. Harsing
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Correspondence: ; Tel.: +36-1-210-4416
| | - Gábor Szénási
- Institute of Translational Medicine, Semmelweis University, H-1089 Budapest, Hungary;
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary
| |
Collapse
|
12
|
Bryche B, Baly C, Meunier N. Modulation of olfactory signal detection in the olfactory epithelium: focus on the internal and external environment, and the emerging role of the immune system. Cell Tissue Res 2021; 384:589-605. [PMID: 33961125 PMCID: PMC8102665 DOI: 10.1007/s00441-021-03467-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/26/2021] [Indexed: 12/18/2022]
Abstract
Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing environment. Part of these adaptations includes changes of odorant detection by olfactory sensory neurons localized in the olfactory epithelium. It is now well established that internal signals such as hormones, neurotransmitters, or paracrine signals directly affect the electric activity of olfactory neurons. Furthermore, recent data have shown that activity-dependent survival of olfactory neurons is important in the olfactory epithelium. Finally, as olfactory neurons are directly exposed to environmental toxicants and pathogens, the olfactory epithelium also interacts closely with the immune system leading to neuroimmune modulations. Here, we review how detection of odorants can be modulated in the vertebrate olfactory epithelium. We choose to focus on three cellular types of the olfactory epithelium (the olfactory sensory neuron, the sustentacular and microvillar cells) to present the diversity of modulation of the detection of odorant in the olfactory epithelium. We also present some of the growing literature on the importance of immune cells in the functioning of the olfactory epithelium, although their impact on odorant detection is only just beginning to be unravelled.
Collapse
Affiliation(s)
- Bertrand Bryche
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France
| | - Christine Baly
- Université Paris Saclay, INRAE, UVSQ, BREED, 78350, Jouy-en-Josas, France
| | - Nicolas Meunier
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France.
| |
Collapse
|
13
|
Brouns I, Verckist L, Pintelon I, Timmermans JP, Adriaensen D. Pulmonary Sensory Receptors. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2021; 233:1-65. [PMID: 33950466 DOI: 10.1007/978-3-030-65817-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Inge Brouns
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium.
| | - Line Verckist
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Dirk Adriaensen
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| |
Collapse
|
14
|
Functional P2X 7 Receptors in the Auditory Nerve of Hearing Rodents Localize Exclusively to Peripheral Glia. J Neurosci 2021; 41:2615-2629. [PMID: 33563723 DOI: 10.1523/jneurosci.2240-20.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/03/2020] [Accepted: 01/09/2021] [Indexed: 11/21/2022] Open
Abstract
P2X7 receptors (P2X7Rs) are associated with numerous pathophysiological mechanisms, and this promotes them as therapeutic targets for certain neurodegenerative conditions. However, the identity of P2X7R-expressing cells in the nervous system remains contentious. Here, we examined P2X7R functionality in auditory nerve cells from rodents of either sex, and determined their functional and anatomic expression pattern. In whole-cell recordings from rat spiral ganglion cultures, the purinergic agonist 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) activated desensitizing currents in spiral ganglion neurons (SGNs) but non-desensitizing currents in glia that were blocked by P2X7R-specific antagonists. In imaging experiments, BzATP gated sustained Ca2+ entry into glial cells. BzATP-gated uptake of the fluorescent dye YO-PRO-1 was reduced and slowed by P2X7R-specific antagonists. In rats, P2X7Rs were immuno-localized predominantly within satellite glial cells (SGCs) and Schwann cells (SCs). P2X7R expression was not detected in the portion of the auditory nerve within the central nervous system. Mouse models allowed further exploration of the distribution of cochlear P2X7Rs. In GENSAT reporter mice, EGFP expression driven via the P2rx7 promoter was evident in SGCs and SCs but was undetectable in SGNs. A second transgenic model showed a comparable cellular distribution of EGFP-tagged P2X7Rs. In wild-type mice the discrete glial expression was confirmed using a P2X7-specific nanobody construct. Our study shows that P2X7Rs are expressed by peripheral glial cells, rather than by afferent neurons. Description of functional signatures and cellular distributions of these enigmatic proteins in the peripheral nervous system (PNS) will help our understanding of ATP-dependent effects contributing to hearing loss and other sensory neuropathies.SIGNIFICANCE STATEMENT P2X7 receptors (P2X7Rs) have been the subject of much scrutiny in recent years. They have been promoted as therapeutic targets in a number of diseases of the nervous system, yet the specific cellular location of these receptors remains the subject of intense debate. In the auditory nerve, connecting the inner ear to the brainstem, we show these multimodal ATP-gated channels localize exclusively to peripheral glial cells rather than the sensory neurons, and are not evident in central glia. Physiologic responses in the peripheral glia display classical hallmarks of P2X7R activation, including the formation of ion-permeable and also macromolecule-permeable pores. These qualities suggest these proteins could contribute to glial-mediated inflammatory processes in the auditory periphery under pathologic disease states.
Collapse
|
15
|
Purinergic Signaling Controls Spontaneous Activity in the Auditory System throughout Early Development. J Neurosci 2020; 41:594-612. [PMID: 33303678 DOI: 10.1523/jneurosci.2178-20.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/06/2020] [Accepted: 11/25/2020] [Indexed: 12/23/2022] Open
Abstract
Spontaneous bursts of electrical activity in the developing auditory system arise within the cochlea before hearing onset and propagate through future sound-processing circuits of the brain to promote maturation of auditory neurons. Studies in isolated cochleae revealed that this intrinsically generated activity is initiated by ATP release from inner supporting cells (ISCs), resulting in activation of purinergic autoreceptors, K+ efflux, and subsequent depolarization of inner hair cells. However, it is unknown when this activity emerges or whether different mechanisms induce activity during distinct stages of development. Here we show that spontaneous electrical activity in mouse cochlea from both sexes emerges within ISCs during the late embryonic period, preceding the onset of spontaneous correlated activity in inner hair cells and spiral ganglion neurons, which begins at birth and follows a base to apex developmental gradient. At all developmental ages, pharmacological inhibition of P2Y1 purinergic receptors dramatically reduced spontaneous activity in these three cell types. Moreover, in vivo imaging within the inferior colliculus revealed that auditory neurons within future isofrequency zones exhibit coordinated neural activity at birth. The frequency of these discrete bursts increased progressively during the postnatal prehearing period yet remained dependent on P2RY1. Analysis of mice with disrupted cholinergic signaling in the cochlea indicate that this efferent input modulates, rather than initiates, spontaneous activity before hearing onset. Thus, the auditory system uses a consistent mechanism involving ATP release from ISCs and activation of P2RY1 autoreceptors to elicit coordinated excitation of neurons that will process similar frequencies of sound.SIGNIFICANCE STATEMENT In developing sensory systems, groups of neurons that will process information from similar sensory space exhibit highly correlated electrical activity that is critical for proper maturation and circuit refinement. Defining the period when this activity is present, the mechanisms responsible and the features of this activity are crucial for understanding how spontaneous activity influences circuit development. We show that, from birth to hearing onset, the auditory system relies on a consistent mechanism to elicit correlate firing of neurons that will process similar frequencies of sound. Targeted disruption of this activity will increase our understanding of how these early circuits mature and may provide insight into processes responsible for developmental disorders of the auditory system.
Collapse
|
16
|
Saffron: Chemical Composition and Neuroprotective Activity. Molecules 2020; 25:molecules25235618. [PMID: 33260389 PMCID: PMC7731018 DOI: 10.3390/molecules25235618] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
Crocus sativus L. belongs to the Iridaceae family and it is commonly known as saffron. The different cultures together with the geoclimatic characteristics of the territory determine a different chemical composition that characterizes the final product. This is why a complete knowledge of this product is fundamental, from which more than 150 chemical compounds have been extracted from, but only about one third of them have been identified. The chemical composition of saffron has been studied in relation to its efficacy in coping with neurodegenerative retinal diseases. Accordingly, experimental results provide evidence of a strict correlation between chemical composition and neuroprotective capacity. We found that saffron's ability to cope with retinal neurodegeneration is related to: (1) the presence of specific crocins and (2) the contribution of other saffron components. We summarize previous evidence and provide original data showing that results obtained both "in vivo" and "in vitro" lead to the same conclusion.
Collapse
|
17
|
Fletcher EL. Advances in understanding the mechanisms of retinal degenerations. Clin Exp Optom 2020; 103:723-732. [PMID: 33090561 DOI: 10.1111/cxo.13146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 01/13/2023] Open
Abstract
Photoreceptor death is an important contributor to irreversible vision loss worldwide. In this review, I outline our work examining the role that purines, such as adenosine triphosphate (ATP), have in normal retinal function and in retinal disease. Our work shows that the actions of ATP, mediated by P2X receptors, are expressed in various retinal layers including photoreceptor terminals, and when stimulated by excessive levels of ATP is associated with rapid death of neurons. Treatment with a compound that blocks the action of P2X and some P2Y receptors reduces photoreceptor death in a mouse model of retinal degeneration. Our observations not only provide a means for developing a potential treatment for reducing photoreceptor death, but also provides a novel way of studying the neural plasticity effects that develop in the inner retina following photoreceptor death. There are a range of inner retinal changes that could influence the effectiveness of retinal prostheses. Indeed, using an ATP-induced degeneration model, we established that the amount of electrical stimulation required to elicit a response in the visual cortex was affected by the level of glial scarring. However, changes in P2X7 receptor expression by OFF ganglion cells during retinal degeneration can also be exploited by photoswitches to restore light sensitivity to degenerated retinae. Finally, our work has also considered how P2X7 expression by innate immune cells, and its role as a scavenger receptor, contributes to age-related macular degeneration (AMD). Our results show that loss of P2X7 function is associated with thickening of Bruch's membrane as well as increased risk of advanced disease in people with AMD. Overall, our work over the last 20 years highlights the importance of purinergic signalling in normal retinal function and retinal disease and suggest that developing therapies that target P2X7 function could be of benefit for these diseases.
Collapse
Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
18
|
Jovanovic S, Milenkovic I. Purinergic Modulation of Activity in the Developing Auditory Pathway. Neurosci Bull 2020; 36:1285-1298. [PMID: 33040238 DOI: 10.1007/s12264-020-00586-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
Purinergic P2 receptors, activated by endogenous ATP, are prominently expressed on neuronal and non-neuronal cells during development of the auditory periphery and central auditory neurons. In the mature cochlea, extracellular ATP contributes to ion homeostasis, and has a protective function against noise exposure. Here, we focus on the modulation of activity by extracellular ATP during early postnatal development of the lower auditory pathway. In mammals, spontaneous patterned activity is conveyed along afferent auditory pathways before the onset of acoustically evoked signal processing. During this critical developmental period, inner hair cells fire bursts of action potentials that are believed to provide a developmental code for synaptic maturation and refinement of auditory circuits, thereby establishing a precise tonotopic organization. Endogenous ATP-release triggers such patterned activity by raising the extracellular K+ concentration and contributes to firing by increasing the excitability of auditory nerve fibers, spiral ganglion neurons, and specific neuron types within the auditory brainstem, through the activation of diverse P2 receptors. We review recent studies that provide new models on the contribution of purinergic signaling to early development of the afferent auditory pathway. Further, we discuss potential future directions of purinergic research in the auditory system.
Collapse
Affiliation(s)
- Sasa Jovanovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany
| | - Ivan Milenkovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany.
| |
Collapse
|
19
|
Kong Y, Wang Q, Wu DY, Hu J, Zang WS, Li XW, Yang JM, Gao TM. Involvement of P2X2 receptor in the medial prefrontal cortex in ATP modulation of the passive coping response to behavioral challenge. GENES BRAIN AND BEHAVIOR 2020; 19:e12691. [PMID: 32761745 DOI: 10.1111/gbb.12691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/01/2020] [Accepted: 08/04/2020] [Indexed: 12/22/2022]
Abstract
P2X2 and P2X3 receptors are widely expressed in both the peripheral nervous system and the central nervous system and have been proven to participate in different peripheral sensory functions, but there are few studies on the involvement of P2X2 and P2X3 receptors in animal behaviors. Here we used P2X2 and P2X3 knockout mice to address this issue. P2X2 knockout mice showed normal motor function, exploratory behavior, anxiety-like behaviors, learning and memory behaviors and passive coping response to behavioral challenge. Nevertheless, the effect of ATP infusion in the medial prefrontal cortex (mPFC) on the passive coping response was blocked by P2X2 but not P2X3 receptor deletion. Additionally, no deficits in a wide variety of behavioral tests were observed in P2X3 knockout mice. These findings demonstrate a role of P2X2 receptor in the mPFC in adenosine-5'-triphosphate modulation of the passive coping response to behavioral challenge and show that the P2X2/P2X3 receptor is dispensable for behaviors.
Collapse
Affiliation(s)
- Ying Kong
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Qian Wang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ding-Yu Wu
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jian Hu
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wen-Si Zang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiao-Wen Li
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jian-Ming Yang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Tian-Ming Gao
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Psychiatric Disorders of Guangdong Province, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| |
Collapse
|
20
|
Romano GL, Amato R, Lazzara F, Porciatti V, Chou TH, Drago F, Bucolo C. P2X7 receptor antagonism preserves retinal ganglion cells in glaucomatous mice. Biochem Pharmacol 2020; 180:114199. [PMID: 32798466 DOI: 10.1016/j.bcp.2020.114199] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/29/2020] [Accepted: 08/11/2020] [Indexed: 02/07/2023]
Abstract
To investigate the role of P2X7 receptor to preserve retinal ganglion cells (RGCs) structure and function in a genetic mouse model (DBA/2J mouse) of age-related glaucomatous neurodegeneration. Chronic treatment with P2X7 receptor antagonist eye drops was carried out in order to assess RGCs function and density by pattern electroretinogram (PERG) and RBPMS immunostaining, respectively. Further, microglia activation was assessed in flat-mounted retina by using Iba-1 immunostaining. Untreated glaucomatous eyes displayed significant microglia activation, alteration of PERG signal, and RGCs loss. In the P2X7 receptor antagonist-treated eyes, the PERG signal was significantly (p < 0.05) improved compared to controls, along with a significant (p < 0.05) reduction in terms of retinal microglial activation, and remarkable preservation of RGCs density. Altogether, these findings demonstrated that topical treatment with a P2X7 receptor antagonist has a neuroprotective effect on RGCs in glaucomatous mice, suggesting an appealing pharmacological approach to prevent retinal degenerative damage in optic neuropathy.
Collapse
Affiliation(s)
- Giovanni Luca Romano
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Rosario Amato
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States; Department of Biology, University of Pisa, Pisa, Italy
| | - Francesca Lazzara
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Filippo Drago
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| |
Collapse
|
21
|
Mazzarda F, D'Elia A, Massari R, De Ninno A, Bertani FR, Businaro L, Ziraldo G, Zorzi V, Nardin C, Peres C, Chiani F, Tettey-Matey A, Raspa M, Scavizzi F, Soluri A, Salvatore AM, Yang J, Mammano F. Organ-on-chip model shows that ATP release through connexin hemichannels drives spontaneous Ca 2+ signaling in non-sensory cells of the greater epithelial ridge in the developing cochlea. LAB ON A CHIP 2020; 20:3011-3023. [PMID: 32700707 DOI: 10.1039/d0lc00427h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Prior work supports the hypothesis that ATP release through connexin hemichannels drives spontaneous Ca2+ signaling in non-sensory cells of the greater epithelial ridge (GER) in the developing cochlea; however, direct proof is lacking. To address this issue, we plated cochlear organotypic cultures (COCs) and whole cell-based biosensors with nM ATP sensitivity (ATP-WCBs) at the bottom and top of an ad hoc designed transparent microfluidic chamber, respectively. By performing dual multiphoton Ca2+ imaging, we monitored the propagation of intercellular Ca2+ waves in the GER of COCs and ATP-dependent Ca2+ responses in overlying ATP-WCBs. Ca2+ signals in both COCs and ATP-WCBs were inhibited by supplementing the extracellular medium with ATP diphosphohydrolase (apyrase). Spontaneous Ca2+ signals were strongly depressed in the presence of Gjb6-/- COCs, in which connexin 30 (Cx30) is absent and connexin 26 (Cx26) is strongly downregulated. In contrast, spontaneous Ca2+ signals were not affected by replacement of Panx1-/- with Panx1+/+ COCs in the microfluidic chamber. Similar results were obtained by estimating ATP release from COCs using a classical luciferin-luciferase bioluminescence assay. Therefore, connexin hemichannels and not pannexin 1 channels mediate the release of ATP that is responsible for Ca2+ wave propagation in the developing mouse cochlea. The technological advances presented here have the potential to shed light on a plethora of unrelated open issues that involve paracrine signaling in physiology and pathology and cannot be addressed with standard methods.
Collapse
Affiliation(s)
- Flavia Mazzarda
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy. and Department of Science, Università degli Studi di Roma3, Rome, Italy
| | - Annunziata D'Elia
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy. and Department of Science, Università degli Studi di Roma3, Rome, Italy
| | - Roberto Massari
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | - Adele De Ninno
- CNR Institute for Photonics and Nanotechnology, Rome, Italy.
| | | | - Luca Businaro
- CNR Institute for Photonics and Nanotechnology, Rome, Italy.
| | - Gaia Ziraldo
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy. and Institute of Otorhinolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Veronica Zorzi
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy. and Institute of Otorhinolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Chiara Nardin
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | - Chiara Peres
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | - Francesco Chiani
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | | | - Marcello Raspa
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | | | - Alessandro Soluri
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy.
| | | | - Jun Yang
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. and Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, China
| | - Fabio Mammano
- CNR Institute of Biochemistry and Cell Biology, Monterotondo, Rome, Italy. and Department of Physics and Astronomy "G. Galilei", University of Padova, Padua, Italy.
| |
Collapse
|
22
|
The Purinergic Receptor P2rx3 is Required for Spiral Ganglion Neuron Branch Refinement during Development. eNeuro 2020; 7:ENEURO.0179-20.2020. [PMID: 32675174 PMCID: PMC7418533 DOI: 10.1523/eneuro.0179-20.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/03/2020] [Accepted: 07/08/2020] [Indexed: 12/18/2022] Open
Abstract
The mammalian cochlea undergoes a highly dynamic process of growth and innervation during development. This process includes spiral ganglion neuron (SGN) branch refinement, a process whereby Type I SGNs undergo a phase of “debranching” before forming unramified synaptic contacts with inner hair cells. Using Sox2CreERT2 and R26RtdTomato as a strategy to genetically label individual SGNs in mice of both sexes, we report on both a time course of SGN branch refinement and a role for P2rx3 in this process. P2rx3 is an ionotropic ATP receptor that was recently implicated in outer hair cell spontaneous activity and Type II SGN synapse development (Ceriani et al., 2019), but its function in Type I SGN development is unknown. Here, we demonstrate that P2rx3 is expressed by Type I SGNs and hair cells during developmental periods that coincide with SGN branching refinement. P2rx3 null mice show SGNs with more complex branching patterns on their peripheral synaptic terminals and near their cell bodies around the time of birth. Loss of P2rx3 does not appear to confer general changes in axon outgrowth or hair cell formation, and alterations in branching complexity appear to mostly recover by postnatal day (P)6. However, when we examined the distribution of Type I SGN subtypes using antibodies that bind Calb2, Calb1, and Pou4f1, we found that P2rx3 null mice showed an increased proportion of SGNs that express Calb2. These data suggest P2rx3 may be necessary for normal Type I SGN differentiation in addition to serving a role in branch refinement.
Collapse
|
23
|
Basu M, Gupta P, Dutta A, Jana K, Ukil A. Increased host ATP efflux and its conversion to extracellular adenosine is crucial for establishing Leishmania infection. J Cell Sci 2020; 133:jcs239939. [PMID: 32079656 DOI: 10.1242/jcs.239939] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 02/07/2020] [Indexed: 12/19/2022] Open
Abstract
Intracellular survival of Leishmania donovani demands rapid production of host ATP for its sustenance. However, a gradual decrease in intracellular ATP in spite of increased glycolysis suggests ATP efflux during infection. Accordingly, upon infection, we show here that ATP is exported and the major exporter was pannexin-1, leading to raised extracellular ATP levels. Extracellular ATP shows a gradual decrease after the initial increase, and analysis of cell surface ATP-degrading enzymes revealed induction of the ectonucleotidases CD39 and CD73. Ectonucleotidase-mediated ATP degradation leads to increased extracellular adenosine (eADO), and inhibition of CD39 and CD73 in infected cells decreased adenosine concentration and parasite survival, documenting the importance of adenosine in infection. Inhibiting adenosine uptake by cells did not affect parasite survival, suggesting that eADO exerts its effect through receptor-mediated signalling. We also show that Leishmania induces the expression of adenosine receptors A2AR and A2BR, both of which are important for anti-inflammatory responses. Treating infected BALB/c mice with CD39 and CD73 inhibitors resulted in decreased parasite burden and increased host-favourable cytokine production. Collectively, these observations indicate that infection-induced ATP is exported, and after conversion into adenosine, propagates infection via receptor-mediated signalling.
Collapse
Affiliation(s)
- Moumita Basu
- Department of Biochemistry, University of Calcutta, Kolkata 700019, West Bengal, India
| | - Purnima Gupta
- Infections and Cancer Biology Group, International Agency for Research on Cancer, 69372, Lyon Cedex 08, France
| | - Ananya Dutta
- Division of Molecular Medicine, Bose Institute, P1/12 Calcutta Improvement Trust Scheme, VIIM, Kolkata, 700054, West Bengal, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, P1/12 Calcutta Improvement Trust Scheme, VIIM, Kolkata, 700054, West Bengal, India
| | - Anindita Ukil
- Department of Biochemistry, University of Calcutta, Kolkata 700019, West Bengal, India
| |
Collapse
|
24
|
Medrano MP, Pisera-Fuster A, Bernabeu RO, Faillace MP. P2X7 and A 2A receptor endogenous activation protects against neuronal death caused by CoCl 2 -induced photoreceptor toxicity in the zebrafish retina. J Comp Neurol 2020; 528:2000-2020. [PMID: 31997350 DOI: 10.1002/cne.24869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 01/09/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
Injured retinas in mammals do not regenerate and heal with loss of function. The adult retina of zebrafish self-repairs after damage by activating cell-intrinsic mechanisms, which are regulated by extrinsic signal interactions. Among relevant regulatory extrinsic systems, purinergic signaling regulates progenitor proliferation during retinogenesis and regeneration and glia proliferation in proliferative retinopathies. ATP-activated P2X7 (P2RX7) and adenosine (P1R) receptors are involved in the progression of almost all retinopathies leading to blindness. Here, we examined P2RX7 and P1R participation in the retina regenerative response induced by photoreceptor damage caused by a specific dose of CoCl2 . First, we found that treatment of uninjured retinas with a potent agonist of P2RX7 (BzATP) provoked photoreceptor damage and mitotic activation of multipotent progenitors. In CoCl2 -injured retinas, blockade of endogenous extracellular ATP activity on P2RX7 caused further neurodegeneration, Müller cell gliosis, progenitor proliferation, and microglia reactivity. P2RX7 inhibition in injured retinas also increased the expression of lin28a and tnfα genes, which are related to multipotent progenitor proliferation. Levels of hif1α, vegf3r, and vegfaa mRNA were enhanced by blockade of P2RX7 immediately after injury, indicating hypoxic like damage and endothelial cell growth and proliferation. Complete depletion of extracellular nucleotides with an apyrase treatment strongly potentiated cell death and progenitor proliferation induced with CoCl2 . Blockade of adenosine P1 and A2A receptors (A2A R) had deleterious effects and deregulated normal timing for progenitor and precursor cell proliferation following photoreceptor damage. ATP via P2RX7 and adenosine via A2A R are survival extracellular signals key for retina regeneration in zebrafish.
Collapse
Affiliation(s)
- Matías P Medrano
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Antonella Pisera-Fuster
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ramón O Bernabeu
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - María Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| |
Collapse
|
25
|
Babola TA, Kersbergen CJ, Wang HC, Bergles DE. Purinergic signaling in cochlear supporting cells reduces hair cell excitability by increasing the extracellular space. eLife 2020; 9:e52160. [PMID: 31913121 PMCID: PMC7015667 DOI: 10.7554/elife.52160] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/07/2020] [Indexed: 11/13/2022] Open
Abstract
Neurons in developing sensory pathways exhibit spontaneous bursts of electrical activity that are critical for survival, maturation and circuit refinement. In the auditory system, intrinsically generated activity arises within the cochlea, but the molecular mechanisms that initiate this activity remain poorly understood. We show that burst firing of mouse inner hair cells prior to hearing onset requires P2RY1 autoreceptors expressed by inner supporting cells. P2RY1 activation triggers K+ efflux and depolarization of hair cells, as well as osmotic shrinkage of supporting cells that dramatically increased the extracellular space and speed of K+ redistribution. Pharmacological inhibition or genetic disruption of P2RY1 suppressed neuronal burst firing by reducing K+ release, but unexpectedly enhanced their tonic firing, as water resorption by supporting cells reduced the extracellular space, leading to K+ accumulation. These studies indicate that purinergic signaling in supporting cells regulates hair cell excitability by controlling the volume of the extracellular space.
Collapse
Affiliation(s)
- Travis A Babola
- The Solomon Snyder Department of NeuroscienceJohns Hopkins UniversityBaltimoreUnited States
| | - Calvin J Kersbergen
- The Solomon Snyder Department of NeuroscienceJohns Hopkins UniversityBaltimoreUnited States
| | - Han Chin Wang
- The Solomon Snyder Department of NeuroscienceJohns Hopkins UniversityBaltimoreUnited States
| | - Dwight E Bergles
- The Solomon Snyder Department of NeuroscienceJohns Hopkins UniversityBaltimoreUnited States
- Department of Otolaryngology Head and Neck SurgeryJohns Hopkins UniversityBaltimoreUnited States
- Kavli Neuroscience Discovery InstituteJohns Hopkins UniversityBaltimoreUnited States
| |
Collapse
|
26
|
Reichenbach A, Bringmann A. Glia of the human retina. Glia 2019; 68:768-796. [PMID: 31793693 DOI: 10.1002/glia.23727] [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: 04/30/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/22/2022]
Abstract
The human retina contains three types of glial cells: microglia and two types of macroglia, astrocytes and Müller cells. Macroglia provide homeostatic and metabolic support to photoreceptors and neurons required for neuronal activity. The fovea, the site of the sharpest vision which is astrocyte- and microglia-free, contains two populations of Müller glia: cells which form the Müller cell cone in the foveola and z-shaped Müller cells of the foveal walls. Both populations are characterized by morphological and functional differences. Müller cells of the foveola do not support the activity of photoreceptors and neurons, but provide the structural stability of the foveal tissue and improve the light transmission through the tissue to the photoreceptors. This article gives overviews of the glia of the human retina and the structure and function of both Müller cell types in the fovea, and describes the contributions of astrocytes and Müller cells to the ontogenetic development of the fovea.
Collapse
Affiliation(s)
- Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| |
Collapse
|
27
|
Liu XZ, Yan D, Mittal R, Ballard ME, Feng Y. Progressive Dominant Hearing Loss (Autosomal Dominant Deafness-41) and P2RX2 Gene Mutations: A Phenotype-Genotype Study. Laryngoscope 2019; 130:1657-1663. [PMID: 31593348 DOI: 10.1002/lary.28318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/29/2019] [Accepted: 08/28/2019] [Indexed: 01/14/2023]
Abstract
OBJECTIVES/HYPOTHESIS P2RX2 encoding P2X purinoreceptor 2 has been identified as the gene responsible for autosomal dominant deafness-41 (DFNA41) as well as mediating vulnerability to noise-induced hearing loss (NIHL). The objective of this study was to investigate the audiological and molecular characteristics of P2RX2-related deafness, with emphasis on its role in NIHL by determining the audiological characteristics of a previously reported six-generation DFNA41 family with a 10-year follow-up. We have also summarized phenotype-genotype correlations of P2RX2-related deafness in human and mouse models. STUDY DESIGN We describe clinical longitudinal follow-up in the DFNA41 family with P2RX2 (p.Val60Leu) mutation and perform a systematic literature search in PubMed and poster presentations on meeting/conference websites to identify current insights into P2RX2-mediated NIHL. METHODS Clinical and physical examinations of the family members were performed, and audiograms were obtained to assess the hearing thresholds. Clinical follow-up features in this DFNA41 family are presented along with correlation analyses of phenotype-genotype in all reported families with P2RX2-related deafness. RESULTS Progressive hearing impairment was confirmed by history and by audiological follow-up testing in all the patients. The onset of hearing loss was between age 25 and 35 years. All affected subjects had bilateral sensorineural hearing loss involving all frequencies with some significant gender differences. CONCLUSIONS Our study and the review of the literature suggest that P2RX2 plays a crucial role in predisposition to noise-induced and age-related hearing loss. A better knowledge about the P2RX2-associated genetic variants can help in developing novel therapeutic strategies. LEVEL OF EVIDENCE 2b Laryngoscope, 130:1657-1663, 2020.
Collapse
Affiliation(s)
- Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, U.S.A.,Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, Florida, U.S.A
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, U.S.A
| | - Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, U.S.A
| | - Megan E Ballard
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, U.S.A
| | - Yong Feng
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
28
|
Cederholm JME, Ryan AF, Housley GD. Onset kinetics of noise-induced purinergic adaptation of the 'cochlear amplifier'. Purinergic Signal 2019; 15:343-355. [PMID: 31377959 PMCID: PMC6737159 DOI: 10.1007/s11302-019-09648-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/06/2019] [Indexed: 12/18/2022] Open
Abstract
A major component of slowly reversible hearing loss which develops with sustained exposure to noise has been attributed to release of ATP in the cochlea activating P2X2 receptor (P2X2R) type ATP-gated ion channels. This purinergic humoral adaptation is thought to enable the highly sensitive hearing organ to maintain function with loud sound, protecting the ear from acoustic overstimulation. In the study that established this hearing adaptation mechanism as reported by Housley et al. (Proc Natl Acad Sci U S A 110:7494-7499, 2013), the activation kinetics were determined in mice from auditory brainstem response (ABR) threshold shifts with sustained noise presentation at time points beyond 10 min. The present study was designed to achieve finer resolution of the onset kinetics of purinergic hearing adaptation, and included the use of cubic (2f1-f2) distortion product otoacoustic emissions (DPOAEs) to probe whether the active mechanical outer hair cell 'cochlear amplifier' contributed to this process. We show that the ABR and DPOAE threshold shifts were largely complete within the first 7.5 min of moderate broadband noise (85 dB SPL) in wildtype C57Bl/6J mice. The ABR and DPOAE adaptation rates were both best fitted by a single exponential function with ~ 3 min time constants. ABR and DPOAE threshold shifts with this noise were minimal in mice null for the P2rx2 gene encoding the P2X2R. The findings demonstrate a considerably faster purinergic hearing adaptation to noise than previously appreciated. Moreover, they strongly implicate the outer hair cell as the site of action, as the DPOAEs stem from active cochlear electromotility.
Collapse
Affiliation(s)
- Jennie M E Cederholm
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Allen F Ryan
- Departments of Surgery and Neurosciences, University of California San Diego, La Jolla, CA, USA
- Veterans Administration Medical Center, La Jolla, CA, USA
| | - Gary D Housley
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia.
| |
Collapse
|
29
|
Chen J, Hou S, Yang J. ATP is stored in lysosomes of greater epithelial ridge supporting cells in newborn rat cochleae. J Cell Biochem 2019; 120:19469-19481. [PMID: 31264740 DOI: 10.1002/jcb.29251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/11/2019] [Indexed: 11/11/2022]
Abstract
Adenosine triphosphate (ATP), which plays a crucial role in both developing and mature cochleae, is released from greater epithelial ridge (GER) supporting cells of the rat cochlea, but the organelles in which ATP is stored have not yet been identified. Thus, we studied the organelles involved in ATP storage and suggest that lysosomes provide this function. GER supporting cells of newborn rats were isolated, purified, and cultured, and labeled vesicles within the supporting cells were identified via confocal microscopy and transmission electron microscopy (TEM). ATP release from GER supporting cells after glycyl-L-phenylalanine-β-naphthylamide (GPN) treatment was measured. The specifically labeled organelles observed by confocal microscopy and TEM were lysosomes, and GPN treatment enhanced ATP luminescence in the extracellular fluid of the supporting cells. The release of ATP from supporting cells was affected by changes in intra- and extracellular Ca2+ concentrations. In addition, changes in the intracellular Ca2+ caused by inhibiting the phospholipase signaling pathway affected the release of ATP from supporting cells. We demonstrated that ATP is stored in the lysosomes of GER supporting cells within newborn rat cochleae and that ATP release from GER supporting cells may be Ca2+ -dependent.
Collapse
Affiliation(s)
- Jiarui Chen
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Otorhinolaryngology-Head & Neck Surgery, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Shule Hou
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jun Yang
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| |
Collapse
|
30
|
Inner Ear Connexin Channels: Roles in Development and Maintenance of Cochlear Function. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033233. [PMID: 30181354 DOI: 10.1101/cshperspect.a033233] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Connexin 26 and connexin 30 are the prevailing isoforms in the epithelial and connective tissue gap junction systems of the developing and mature cochlea. The most frequently encountered variants of the genes that encode these connexins, which are transcriptionally coregulated, determine complete loss of protein function and are the predominant cause of prelingual hereditary deafness. Reducing connexin 26 expression by Cre/loxP recombination in the inner ear of adult mice results in a decreased endocochlear potential, increased hearing thresholds, and loss of >90% of outer hair cells, indicating that this connexin is essential for maintenance of cochlear function. In the developing cochlea, connexins are necessary for intercellular calcium signaling activity. Ribbon synapses and basolateral membrane currents fail to mature in inner hair cells of mice that are born with reduced connexin expression, even though hair cells do not express any connexin. In contrast, pannexin 1, an alternative mediator of intercellular signaling, is dispensable for hearing acquisition and auditory function.
Collapse
|
31
|
Köles L, Szepesy J, Berekméri E, Zelles T. Purinergic Signaling and Cochlear Injury-Targeting the Immune System? Int J Mol Sci 2019; 20:ijms20122979. [PMID: 31216722 PMCID: PMC6627352 DOI: 10.3390/ijms20122979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.
Collapse
Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Ecology, University of Veterinary Medicine, H-1078 Budapest, Hungary.
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary.
| |
Collapse
|
32
|
Akhtar-Schäfer I, Wang L, Krohne TU, Xu H, Langmann T. Modulation of three key innate immune pathways for the most common retinal degenerative diseases. EMBO Mol Med 2019; 10:emmm.201708259. [PMID: 30224384 PMCID: PMC6180304 DOI: 10.15252/emmm.201708259] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review highlights the role of three key immune pathways in the pathophysiology of major retinal degenerative diseases including diabetic retinopathy, age‐related macular degeneration, and rare retinal dystrophies. We first discuss the mechanisms how loss of retinal homeostasis evokes an unbalanced retinal immune reaction involving responses of local microglia and recruited macrophages, activity of the alternative complement system, and inflammasome assembly in the retinal pigment epithelium. Presenting these key mechanisms as complementary targets, we specifically emphasize the concept of immunomodulation as potential treatment strategy to prevent or delay vision loss. Promising molecules are ligands for phagocyte receptors, specific inhibitors of complement activation products, and inflammasome inhibitors. We comprehensively summarize the scientific evidence for this strategy from preclinical animal models, human ocular tissue analyses, and clinical trials evolving in the last few years.
Collapse
Affiliation(s)
- Isha Akhtar-Schäfer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Luping Wang
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Tim U Krohne
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Heping Xu
- Centre for Experimental Medicine, The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany .,Center for Molecular Medicine, University of Cologne, Cologne, Germany
| |
Collapse
|
33
|
Lin SCY, Thorne PR, Housley GD, Vlajkovic SM. Purinergic Signaling and Aminoglycoside Ototoxicity: The Opposing Roles of P1 (Adenosine) and P2 (ATP) Receptors on Cochlear Hair Cell Survival. Front Cell Neurosci 2019; 13:207. [PMID: 31156393 PMCID: PMC6529511 DOI: 10.3389/fncel.2019.00207] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/24/2019] [Indexed: 01/12/2023] Open
Abstract
Purinergic signaling regulates important physiological processes and the homeostatic response to stress in the cochlea via extracellular nucleosides (adenosine) and nucleotides (ATP, UTP). Using a previously established organotypic culture model, the current study investigated the effect of purinergic P1 (adenosine) and P2 (ATP) receptor activation on the survival of the sensory hair cell population in the cochlea exposed to the ototoxic aminoglycoside neomycin. Organ of Corti explants were obtained from C57BL/6 mice at postnatal day 3 (P3) and maintained in normal culture medium (with or without purine receptor agonists or analogs) for 19.5 h prior to neomycin exposure (1 mM, 3 h) followed by a further incubation for 19.5 h in culture medium. The cochlear explants were then fixed in 4% paraformaldehyde (PFA) and sensory hair cells labeled with Alexa 488-phalloidin. Neomycin induced a substantial loss of the sensory hair cells, mostly in the middle segment of the cochlea. This neomycin-induced ototoxicity was unaffected by the addition of P2 receptor agonists (ATP and UTP) in the culture medium, whilst the addition of their slowly-hydrolyzable analogs (ATPγS, UTPγS) aggravated neomycin-induced sensory hair cell loss. In contrast, the activation of P1 receptors by adenosine or adenosine amine congener (ADAC) conferred partial protection from neomycin ototoxicity. This study demonstrates a pro-survival effect of P1 receptor stimulation, whilst prolonged activation of P2 receptors has an opposite effect. Based on these findings, we postulate that P1 and P2 receptors orchestrate differential responses to cochlear injury and that the balance of these receptors is important for maintaining cochlear homeostasis following ototoxic injury.
Collapse
Affiliation(s)
- Shelly C Y Lin
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Peter R Thorne
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Gary D Housley
- Department of Physiology and Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Srdjan M Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
34
|
Rotermund N, Schulz K, Hirnet D, Lohr C. Purinergic Signaling in the Vertebrate Olfactory System. Front Cell Neurosci 2019; 13:112. [PMID: 31057369 PMCID: PMC6477478 DOI: 10.3389/fncel.2019.00112] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/07/2019] [Indexed: 12/15/2022] Open
Abstract
Adenosine 5'-triphosphate (ATP) is an ubiquitous co-transmitter in the vertebrate brain. ATP itself, as well as its breakdown products ADP and adenosine are involved in synaptic transmission and plasticity, neuron-glia communication and neural development. Although purinoceptors have been demonstrated in the vertebrate olfactory system by means of histological techniques for many years, detailed insights into physiological properties and functional significance of purinergic signaling in olfaction have been published only recently. We review the current literature on purinergic neuromodulation, neuron-glia interactions and neurogenesis in the vertebrate olfactory system.
Collapse
Affiliation(s)
- Natalie Rotermund
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Kristina Schulz
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Daniela Hirnet
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| |
Collapse
|
35
|
Berekméri E, Szepesy J, Köles L, Zelles T. Purinergic signaling in the organ of Corti: Potential therapeutic targets of sensorineural hearing losses. Brain Res Bull 2019; 151:109-118. [PMID: 30721767 DOI: 10.1016/j.brainresbull.2019.01.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/10/2019] [Accepted: 01/25/2019] [Indexed: 01/04/2023]
Abstract
Purinergic signaling is deeply involved in the development, functions and protective mechanisms of the cochlea. Release of ATP and activation of purinergic receptors on sensory and supporting/epithelial cells play a substantial role in cochlear (patho)physiology. Both the ionotropic P2X and the metabotropic P2Y receptors are widely distributed on the inner and outer hair cells as well as on the different supporting cells in the organ of Corti and on other epithelial cells in the scala media. Among others, they are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics acting on outer hair cells and supporting cells. Cochlear blood flow is also regulated by purines. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy. Decreasing hearing sensitivity and increasing cochlear blood supply by pharmacological targeting of purinergic signaling in the cochlea are potential new therapeutic approaches in these hearing disabilities, especially in the noise-induced ones.
Collapse
Affiliation(s)
- Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary; Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
| |
Collapse
|
36
|
Soluble and membrane-bound adenylate kinase and nucleotidases augment ATP-mediated inflammation in diabetic retinopathy eyes with vitreous hemorrhage. J Mol Med (Berl) 2019; 97:341-354. [PMID: 30617853 PMCID: PMC6394560 DOI: 10.1007/s00109-018-01734-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/23/2018] [Accepted: 12/17/2018] [Indexed: 12/28/2022]
Abstract
Abstract ATP and adenosine are important signaling molecules involved in vascular remodeling, retinal function, and neurovascular coupling in the eye. Current knowledge on enzymatic pathways governing the duration and magnitude of ocular purinergic signaling is incompletely understood. By employing sensitive analytical assays, this study dissected ocular purine homeostasis as a complex and coordinated network. Along with previously characterized ecto-5′-nucleotidase/CD73 and adenylate kinase activities, other enzymes have been identified in vitreous fluids, including nucleoside triphosphate diphosphohydrolase (NTPDase), adenosine deaminase, and alkaline phosphatase. Strikingly, activities of soluble adenylate kinase, adenosine deaminase, ecto-5′-nucleotidase/CD73, and alkaline phosphatase, as well as intravitreal concentrations of ATP and ADP, were concurrently upregulated in patients suffering from diabetic retinopathy (DR) with non-clearing vitreous hemorrhage (VH), when compared to DR eyes without VH and control eyes operated due to macular hole or pucker. Additional histochemical analysis revealed selective distribution of key ecto-nucleotidases (NTPDase1/CD39, NTPDase2, ecto-5′-nucleotidase/CD73, and alkaline phosphatase) in the human sensory neuroretina and optic nerve head, and also in pathological neofibrovascular tissues surgically excised from patients with advanced proliferative DR. Collectively, these data provide evidence for specific hemorrhage-related shifts in purine homeostasis in DR eyes from the generation of anti-inflammatory adenosine towards a pro-inflammatory and pro-angiogenic ATP-regenerating phenotype. In the future, identifying the exact mechanisms by which a broad spectrum of soluble and membrane-bound enzymes coordinately regulates ocular purine levels and the further translation of purine-converting enzymes as potential therapeutic targets in the treatment of proliferative DR and other vitreoretinal diseases will be an area of intense interest. Key messages NTPDase, alkaline phosphatase, and adenosine deaminase circulate in human vitreous. Purinergic enzymes are up-regulated in diabetic eyes with vitreous hemorrhage. Soluble adenylate kinase maintains high ATP levels in diabetic retinopathy eyes. Ecto-nucleotidases are co-expressed in the human retina and optic nerve head. Alkaline phosphatase is expressed on neovascular tissues excised from diabetic eyes.
Electronic supplementary material The online version of this article (10.1007/s00109-018-01734-0) contains supplementary material, which is available to authorized users.
Collapse
|
37
|
Berekméri E, Deák O, Téglás T, Sághy É, Horváth T, Aller M, Fekete Á, Köles L, Zelles T. Targeted single-cell electroporation loading of Ca 2+ indicators in the mature hemicochlea preparation. Hear Res 2018; 371:75-86. [PMID: 30504093 DOI: 10.1016/j.heares.2018.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/30/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
Ca2+ is an important intracellular messenger and regulator in both physiological and pathophysiological mechanisms in the hearing organ. Investigation of cellular Ca2+ homeostasis in the mature cochlea is hampered by the special anatomy and high vulnerability of the organ. A quick, straightforward and reliable Ca2+ imaging method with high spatial and temporal resolution in the mature organ of Corti is missing. Cell cultures or isolated cells do not preserve the special microenvironment and intercellular communication, while cochlear explants are excised from only a restricted portion of the organ of Corti and usually from neonatal pre-hearing murines. The hemicochlea, prepared from hearing mice allows tonotopic experimental approach on the radial perspective in the basal, middle and apical turns of the organ. We used the preparation recently for functional imaging in supporting cells of the organ of Corti after bulk loading of the Ca2+ indicator. However, bulk loading takes long time, is variable and non-selective, and causes the accumulation of the indicator in the extracellular space. In this study we show the improved labeling of supporting cells of the organ of Corti by targeted single-cell electroporation in mature mouse hemicochlea. Single-cell electroporation proved to be a reliable way of reducing the duration and variability of loading and allowed subcellular Ca2+ imaging by increasing the signal-to-noise ratio, while cell viability was retained during the experiments. We demonstrated the applicability of the method by measuring the effect of purinergic, TRPA1, TRPV1 and ACh receptor stimulation on intracellular Ca2+ concentration at the cellular and subcellular level. In agreement with previous results, ATP evoked reversible and repeatable Ca2+ transients in Deiters', Hensen's and Claudius' cells. TRPA1 and TRPV1 stimulation by AITC and capsaicin, respectively, failed to induce any Ca2+ response in the supporting cells, except in a single Hensen's cell in which AITC evoked transients with smaller amplitude. AITC also caused the displacement of the tissue. Carbachol, agonist of ACh receptors induced Ca2+ transients in about a third of Deiters' and fifth of Hensen's cells. Here we have presented a fast and cell-specific indicator loading method allowing subcellular functional Ca2+ imaging in supporting cells of the organ of Corti in the mature hemicochlea preparation, thus providing a straightforward tool for deciphering the poorly understood regulation of Ca2+ homeostasis in these cells.
Collapse
Affiliation(s)
- Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Orsolya Deák
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tímea Téglás
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Éva Sághy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tamás Horváth
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Máté Aller
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Ádám Fekete
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary.
| |
Collapse
|
38
|
Doktor F, Prager P, Wiedemann P, Kohen L, Bringmann A, Hollborn M. Hypoxic expression of NLRP3 and VEGF in cultured retinal pigment epithelial cells: contribution of P2Y 2 receptor signaling. Purinergic Signal 2018; 14:471-484. [PMID: 30415294 DOI: 10.1007/s11302-018-9631-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/30/2018] [Indexed: 01/24/2023] Open
Abstract
Retinal hypoxia is a major condition of the chronic inflammatory disease age-related macular degeneration. Extracellular ATP is a danger signal which is known to activate the NLRP3 inflammasome in various cell systems. We investigated in cultured human retinal pigment epithelial (RPE) cells whether hypoxia alters the expression of inflammasome-associated genes and whether purinergic receptor signaling contributes to the hypoxic expression of key inflammatory (NLRP3) and angiogenic factor (VEGF) genes. Hypoxia and chemical hypoxia were induced by a 0.2%-O2 atmosphere and addition of CoCl2, respectively. Gene expression was determined with real-time RT-PCR. Cytosolic NLRP3 and (pro-) IL-1β levels, and the extracellular VEGF level, were evaluated with Western blot and ELISA analyses. Cell culture in 0.2% O2 induced expression of NLRP3 and pro-IL-1β genes but not of the pro-IL-18 gene. Hypoxia also increased the cytosolic levels of NLRP3 and (pro-) IL-1β proteins. Inflammasome activation by lysosomal destabilization decreased the cell viability under hypoxic, but not control conditions. In addition to activation of IL-1 receptors, purinergic receptor signaling mediated by a pannexin-dependent release of ATP and a release of adenosine, and activation of P2Y2 and adenosine A1 receptors, was required for the full hypoxic expression of the NLRP3 gene. P2Y2 (but not A1) receptor signaling also contributed to the hypoxic expression and secretion of VEGF. The data indicate that hypoxia induces priming and activation of the NLRP3 inflammasome in cultured RPE cells. The hypoxic NLRP3 and VEGF gene expression and the secretion of VEGF are in part mediated by P2Y2 receptor signaling.
Collapse
Affiliation(s)
- Fabian Doktor
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Philipp Prager
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
- Helios Klinikum Aue, Aue, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany.
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| |
Collapse
|
39
|
Alpár A, Zahola P, Hanics J, Hevesi Z, Korchynska S, Benevento M, Pifl C, Zachar G, Perugini J, Severi I, Leitgeb P, Bakker J, Miklosi AG, Tretiakov E, Keimpema E, Arque G, Tasan RO, Sperk G, Malenczyk K, Máté Z, Erdélyi F, Szabó G, Lubec G, Palkovits M, Giordano A, Hökfelt TG, Romanov RA, Horvath TL, Harkany T. Hypothalamic CNTF volume transmission shapes cortical noradrenergic excitability upon acute stress. EMBO J 2018; 37:e100087. [PMID: 30209240 PMCID: PMC6213283 DOI: 10.15252/embj.2018100087] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 02/06/2023] Open
Abstract
Stress-induced cortical alertness is maintained by a heightened excitability of noradrenergic neurons innervating, notably, the prefrontal cortex. However, neither the signaling axis linking hypothalamic activation to delayed and lasting noradrenergic excitability nor the molecular cascade gating noradrenaline synthesis is defined. Here, we show that hypothalamic corticotropin-releasing hormone-releasing neurons innervate ependymal cells of the 3rd ventricle to induce ciliary neurotrophic factor (CNTF) release for transport through the brain's aqueductal system. CNTF binding to its cognate receptors on norepinephrinergic neurons in the locus coeruleus then initiates sequential phosphorylation of extracellular signal-regulated kinase 1 and tyrosine hydroxylase with the Ca2+-sensor secretagogin ensuring activity dependence in both rodent and human brains. Both CNTF and secretagogin ablation occlude stress-induced cortical norepinephrine synthesis, ensuing neuronal excitation and behavioral stereotypes. Cumulatively, we identify a multimodal pathway that is rate-limited by CNTF volume transmission and poised to directly convert hypothalamic activation into long-lasting cortical excitability following acute stress.
Collapse
Affiliation(s)
- Alán Alpár
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Péter Zahola
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - János Hanics
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Zsófia Hevesi
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
| | - Solomiia Korchynska
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Marco Benevento
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Christian Pifl
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gergely Zachar
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Jessica Perugini
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Ilenia Severi
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Patrick Leitgeb
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Joanne Bakker
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Andras G Miklosi
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gloria Arque
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Ramon O Tasan
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Katarzyna Malenczyk
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Zoltán Máté
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ferenc Erdélyi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gert Lubec
- Paracelsus Medical University, Salzburg, Austria
| | - Miklós Palkovits
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
- Human Brain Tissue Bank and Laboratory, Semmelweis University, Budapest, Hungary
| | - Antonio Giordano
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Tomas Gm Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Departments of Comparative Medicine and Neuroscience, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| |
Collapse
|
40
|
Hackett TA. Adenosine A 1 Receptor mRNA Expression by Neurons and Glia in the Auditory Forebrain. Anat Rec (Hoboken) 2018; 301:1882-1905. [PMID: 30315630 PMCID: PMC6282551 DOI: 10.1002/ar.23907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/05/2017] [Accepted: 01/10/2018] [Indexed: 12/30/2022]
Abstract
In the brain, purines such as ATP and adenosine can function as neurotransmitters and co‐transmitters, or serve as signals in neuron–glial interactions. In thalamocortical (TC) projections to sensory cortex, adenosine functions as a negative regulator of glutamate release via activation of the presynaptic adenosine A1 receptor (A1R). In the auditory forebrain, restriction of A1R‐adenosine signaling in medial geniculate (MG) neurons is sufficient to extend LTP, LTD, and tonotopic map plasticity in adult mice for months beyond the critical period. Interfering with adenosine signaling in primary auditory cortex (A1) does not contribute to these forms of plasticity, suggesting regional differences in the roles of A1R‐mediated adenosine signaling in the forebrain. To advance understanding of the circuitry, in situ hybridization was used to localize neuronal and glial cell types in the auditory forebrain that express A1R transcripts (Adora1), based on co‐expression with cell‐specific markers for neuronal and glial subtypes. In A1, Adora1 transcripts were concentrated in L3/4 and L6 of glutamatergic neurons. Subpopulations of GABAergic neurons, astrocytes, oligodendrocytes, and microglia expressed lower levels of Adora1. In MG, Adora1 was expressed by glutamatergic neurons in all divisions, and subpopulations of all glial classes. The collective findings imply that A1R‐mediated signaling broadly extends to all subdivisions of auditory cortex and MG. Selective expression by neuronal and glial subpopulations suggests that experimental manipulations of A1R‐adenosine signaling could impact several cell types, depending on their location. Strategies to target Adora1 in specific cell types can be developed from the data generated here. Anat Rec, 301:1882–1905, 2018. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
Collapse
Affiliation(s)
- Troy A Hackett
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
41
|
Soliño M, Larrayoz IM, López EM, Vacotto M, Martignone N, Rey-Funes M, Martínez A, Girardi E, López-Costa JJ. The expression of adenosine receptors changes throughout light induced retinal degeneration in the rat. Neurosci Lett 2018; 687:259-267. [PMID: 30291879 DOI: 10.1016/j.neulet.2018.09.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/18/2018] [Accepted: 09/26/2018] [Indexed: 01/24/2023]
Abstract
The modulation of adenosine receptors, A1 (A1R) and A2A (A2AR), is neuroprotective in different models of retinal injury. In order to understand the processes underlying retinal degeneration, we studied the expression of adenosine receptors in the retinas of control and continuously illuminated (CI) rats by qRT-PCR, Western blot (WB) and immunohistochemistry (IHC). Significant increases of A1R, A2AR, and A2BR mRNAs at 1, 5, and 7 days of CI (P < 0.0001) were observed by qRT-PCR. Also, a significant increase of A3R mRNA was detected after 5 and 7 days of CI. WB studies showed a significant rise of A1R on day 1 of CI and on days 5 and 7 (P < 0.0001), while A2AR increase was seen from 2 days of CI on (P < 0.001). After 1 day of CI, A1R immunoreactivity (A1R-IR) increased in ganglion cell layer, inner nuclear layer, and in both the outer and inner plexiform layers. After 2 days of CI, the A1R-IR went back to control levels. After 5 days of CI, a second rise in A1R, which persisted until 7 days of CI, was measured (P < 0.0001). A significant rise of A2aR immunoreactivity was also observed at day 2 of CI at GCL and INL and subsided at days 5 and 7 (P < 0.0001). The observed up-regulation of A1R after 1 day of CI, corresponds with the peak of oxidative stress; while the rise of A2aR at day 2 of CI, coincides with the massive apoptosis of photoreceptors. We postulate that an early modulation of adenosine receptors could delay or prevent the degeneration of photoreceptors.
Collapse
Affiliation(s)
- Manuel Soliño
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ignacio M Larrayoz
- Biomarkers and Molecular Signaling Group, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Ester M López
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Marina Vacotto
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Noelí Martignone
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Manuel Rey-Funes
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Alfredo Martínez
- Angiogenesis Study Group, Center for Biomedical Research of La Rioja (CIBIR), 26006 Logroño, Spain
| | - Elena Girardi
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina
| | - Juan J López-Costa
- Universidad de Buenos Aires, Facultad de Medicina, Dpto. de Biología Celular, Histología, Embriología y Genética, Ciudad Autónoma de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis¨ (IBCN), Ciudad Autónoma de Buenos Aires, Argentina.
| |
Collapse
|
42
|
Effect of Adenosine and Adenosine Receptor Antagonists on Retinal Müller Cell Inwardly Rectifying Potassium Channels under Exogenous Glutamate Stimulation. BIOMED RESEARCH INTERNATIONAL 2018; 2018:2749257. [PMID: 30228984 PMCID: PMC6136502 DOI: 10.1155/2018/2749257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 07/25/2018] [Accepted: 08/13/2018] [Indexed: 12/15/2022]
Abstract
The vitreousness of glaucoma subjects contains elevated glutamate, and excessive extracellular glutamate is toxic to retinal neurons. Therefore, glutamate clearance is potentially impaired in the retina of glaucoma subjects. Müller cells play an important role in maintaining low extracellular levels of neurotransmitters, such as glutamate. A better understanding of the cross-talk between adenosine and glutamate may provide a better characterization of the regulatory network in Müller cells. Here, Müller cells were purified from the rat retina on postnatal day 5 using the papain digestion method. Application of increasing concentrations of glutamate (0-20 mmol/L) caused a dose-dependent decrease in the expression levels of Kir4.1, Kir2.1, GLAST, and GS. Exogenous adenosine regulated Kir channels and subsequently promoted GLAST and GS expression levels in Müller cells under exogenous glutamate stimulation. These effects were partly dependent on adenosine receptors.
Collapse
|
43
|
Sato K, Saigusa D, Saito R, Fujioka A, Nakagawa Y, Nishiguchi KM, Kokubun T, Motoike IN, Maruyama K, Omodaka K, Shiga Y, Uruno A, Koshiba S, Yamamoto M, Nakazawa T. Metabolomic changes in the mouse retina after optic nerve injury. Sci Rep 2018; 8:11930. [PMID: 30093719 PMCID: PMC6085332 DOI: 10.1038/s41598-018-30464-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 07/20/2018] [Indexed: 12/12/2022] Open
Abstract
In glaucoma, although axonal injury drives retinal ganglion cell (RGC) death, little is known about the underlying pathomechanisms. To provide new mechanistic insights and identify new biomarkers, we combined latest non-targeting metabolomics analyses to profile altered metabolites in the mouse whole retina 2, 4, and 7 days after optic nerve crush (NC). Ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry and liquid chromatography Fourier transform mass spectrometry covering wide spectrum of metabolites in combination highlighted 30 metabolites that changed its concentration after NC. The analysis displayed similar changes for purine nucleotide and glutathione as reported previously in another animal model of axonal injury and detected multiple metabolites that increased after the injury. After studying the specificity of the identified metabolites to RGCs in histological sections using imaging mass spectrometry, two metabolites, i.e., L-acetylcarnitine and phosphatidylcholine were increased not only preceding the peak of RGC death in the whole retina but also at the RGC layer (2.3-fold and 1.2-fold, respectively). These phospholipids propose novel mechanisms of RGC death and may serve as early biomarkers of axonal injury. The combinatory metabolomics analyses promise to illuminate pathomechanisms, reveal biomarkers, and allow the discovery of new therapeutic targets of glaucoma.
Collapse
Affiliation(s)
- Kota Sato
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Ophthalmic imaging and information analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Daisuke Saigusa
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Medical Biochemistry, Tohoku University School of Medicine, Sendai, Miyagi, Japan.,LEAP, Japan Agency for Medical Research and Development (AMED), Chiyoda, Tokyo, Japan
| | - Ritsumi Saito
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Medical Biochemistry, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Amane Fujioka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Yurika Nakagawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Koji M Nishiguchi
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Taiki Kokubun
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Ikuko N Motoike
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Department of Systems Bioinformatics, Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Kazuichi Maruyama
- Department of Innovative Visual Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Kazuko Omodaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Ophthalmic imaging and information analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Yukihiro Shiga
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akira Uruno
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Medical Biochemistry, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Seizo Koshiba
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Medical Biochemistry, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Masayuki Yamamoto
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan.,Medical Biochemistry, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan. .,Department of Ophthalmic imaging and information analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan. .,Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan. .,Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
| |
Collapse
|
44
|
P2X 2 Receptor Deficiency in Mouse Vestibular End Organs Attenuates Vestibular Function. Neuroscience 2018; 386:41-50. [PMID: 29944897 DOI: 10.1016/j.neuroscience.2018.06.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 06/13/2018] [Accepted: 06/18/2018] [Indexed: 02/02/2023]
Abstract
P2X2 receptors are ligand-gated cation channels activated by extracellular ATP that modulate neural transmission in various neuronal systems. Although the function and distribution of P2X2 receptors in the cochlea portion of the inner ear are well established, their physiological role in the vestibular portion is still not understood. Therefore, we investigated P2X2 receptor localization in the peripheral vestibular portion, and assessed their physiological function in vivo using P2X2 receptor knock out (P2X2-KO) mice. Histological analysis revealed that P2X2 receptors were localized on the epithelial surface of supporting and transitional cells of the vestibular end organs. To examine vestibular function in P2X2-KO mice, we conducted behavioral tests and tested the vestibulo-ocular reflex (VOR) during sinusoidal rotations. P2X2-KO mice exhibited significant motor balance impairment in the balance beam test. VOR gain in P2X2-KO mice was significantly reduced, with no decrease in the optokinetic response. In conclusion, we showed that P2X2 receptors are mainly localized in the supporting cells of the vestibular inner ear, and the loss of P2X2 receptors causes mild vestibular dysfunction. Taken together, our findings suggest that the P2X2 receptor plays a modulatory role in vestibular function.
Collapse
|
45
|
Adenosine A1 receptor: A neuroprotective target in light induced retinal degeneration. PLoS One 2018; 13:e0198838. [PMID: 29912966 PMCID: PMC6005487 DOI: 10.1371/journal.pone.0198838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/25/2018] [Indexed: 02/04/2023] Open
Abstract
Light induced retinal degeneration (LIRD) is a useful model that resembles human retinal degenerative diseases. The modulation of adenosine A1 receptor is neuroprotective in different models of retinal injury. The aim of this work was to evaluate the potential neuroprotective effect of the modulation of A1 receptor in LIRD. The eyes of rats intravitreally injected with N6-cyclopentyladenosine (CPA), an A1 agonist, which were later subjected to continuous illumination (CI) for 24 h, showed retinas with a lower number of apoptotic nuclei and a decrease of Glial Fibrillary Acidic Protein (GFAP) immunoreactive area than controls. Lower levels of activated Caspase 3 and GFAP were demonstrated by Western Blot (WB) in treated animals. Also a decrease of iNOS, TNFα and GFAP mRNA was demonstrated by RT-PCR. A decrease of Iba 1+/MHC-II+ reactive microglial cells was shown by immunohistochemistry. Electroretinograms (ERG) showed higher amplitudes of a-wave, b-wave and oscillatory potentials after CI compared to controls. Conversely, the eyes of rats intravitreally injected with dipropylcyclopentylxanthine (DPCPX), an A1 antagonist, and subjected to CI for 24 h, showed retinas with a higher number of apoptotic nuclei and an increase of GFAP immunoreactive area compared to controls. Also, higher levels of activated Caspase 3 and GFAP were demonstrated by Western Blot. The mRNA levels of iNOS, nNOS and inflammatory cytokines (IL-1β and TNFα) were not modified by DPCPX treatment. An increase of Iba 1+/MHC-II+ reactive microglial cells was shown by immunohistochemistry. ERG showed that the amplitudes of a-wave, b-wave, and oscillatory potentials after CI were similar to control values. A single pharmacological intervention prior illumination stress was able to swing retinal fate in opposite directions: CPA was neuroprotective, while DPCPX worsened retinal damage. In summary, A1 receptor agonism is a plausible neuroprotective strategy in LIRD.
Collapse
|
46
|
Pérez de Lara MJ, Guzmán-Aranguez A, Gómez-Villafuertes R, Gualix J, Miras-Portugal MT, Pintor J. Increased Ap 4A levels and ecto-nucleotidase activity in glaucomatous mice retina. Purinergic Signal 2018; 14:259-270. [PMID: 29948577 DOI: 10.1007/s11302-018-9612-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/22/2018] [Indexed: 10/14/2022] Open
Abstract
The pathogenesis of glaucoma involves numerous intracellular mechanisms including the purinergic system contribution. Furthermore, the presence and release of nucleotides and dinucleotides during the glaucomatous damage and the maintenance of degradation machinery through ecto-nucleotidase activity are participating in the modulation of the suitable extracellular complex balance. The aim of this study was to investigate the levels of diadenosine tetraphosphate (Ap4A) and the pattern of ecto-nucleotidase activity expression in glaucomatous retinas during the progress the pathology. Ap4A levels were analyzed by HPLC in glaucomatous retinas from the DBA/2J mice at 3, 9, 15, and 23 months of age. For that, retinas were dissected as flattened whole-mounts and stimulated in Ringer buffer with or without 59 mM KCl. NPP1 expression was analyzed by RT-PCR and western blot and its distribution was assessed by immunohistochemistry studies examined under confocal microscopy. Glaucomatous mice exhibited Ap4A values, which changed in stimulated retinas as long as the pathology progressed varying from 0.73 ± 0.04 (3 months) to 0.170 ± 0.05 pmol/mg retina (23 months). Concomitantly, NPP1 expression was significantly increased (82.15%) in the DBA/2J mice at 15 months. Furthermore, immunohistochemical studies showed that NPP1 labeling was stronger in OPL and IPL labeling tangentially in the vitreal part of the retina and was upregulated at 15 months of age. Our findings demonstrate that Ap4A decreased levels may be related with exacerbated activity of NPP1 protein in glaucomatous degeneration and in this way contributing to elucidate different mechanisms involved in retinal impairment in glaucomatous degeneration.
Collapse
Affiliation(s)
- María J Pérez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain
| | - Ana Guzmán-Aranguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain
| | - Rosa Gómez-Villafuertes
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - Javier Gualix
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - María Teresa Miras-Portugal
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain.
| |
Collapse
|
47
|
Knockout of Pannexin-1 Induces Hearing Loss. Int J Mol Sci 2018; 19:ijms19051332. [PMID: 29710868 PMCID: PMC5983795 DOI: 10.3390/ijms19051332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022] Open
Abstract
Mutations of gap junction connexin genes induce a high incidence of nonsyndromic hearing loss. Pannexin genes also encode gap junctional proteins in vertebrates. Recent studies demonstrated that Pannexin-1 (Panx1) deficiency in mice and mutation in humans are also associated with hearing loss. So far, several Panx1 knockout (KO) mouse lines were established. In general, these Panx1 KO mouse lines demonstrate consistent phenotypes in most aspects, including hearing loss. However, a recent study reported that a Panx1 KO mouse line, which was created by Genentech Inc., had no hearing loss as measured by the auditory brainstem response (ABR) threshold at low-frequency range (<24 kHz). Here, we used multiple auditory function tests and re-examined hearing function in the Genentech Panx1 (Gen-Panx1) KO mouse. We found that ABR thresholds in the Gen-Panx1 KO mouse were significantly increased, in particular, in the high-frequency region. Moreover, consistent with the increase in ABR threshold, distortion product otoacoustic emission (DPOAE) and cochlear microphonics (CM), which reflect active cochlear amplification and auditory receptor current, respectively, were significantly reduced. These data demonstrated that the Gen-Panx1 KO mouse has hearing loss and further confirmed that Panx1 deficiency can cause deafness.
Collapse
|
48
|
Rotermund N, Winandy S, Fischer T, Schulz K, Fregin T, Alstedt N, Buchta M, Bartels J, Carlström M, Lohr C, Hirnet D. Adenosine A 1 receptor activates background potassium channels and modulates information processing in olfactory bulb mitral cells. J Physiol 2018; 596:717-733. [PMID: 29274133 DOI: 10.1113/jp275503] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/07/2017] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Adenosine is a widespread neuromodulator in the mammalian brain, but whether it affects information processing in sensory system(s) remains largely unknown. Here we show that adenosine A1 receptors hyperpolarize mitral cells, one class of principal neurons that propagate odour information from the olfactory bulb to higher brain areas, by activation of background K+ channels. The adenosine-modulated background K+ channels belong to the family of two-pore domain K+ channels. Adenosine reduces spontaneous activity of mitral cells, whereas action potential firing evoked by synaptic input upon stimulation of sensory neurons is not affected, resulting in a higher ratio of evoked firing (signal) over spontaneous firing (noise) and hence an improved signal-to-noise ratio. The study shows for the first time that adenosine influences fine-tuning of the input-output relationship in sensory systems. ABSTRACT Neuromodulation by adenosine is of critical importance in many brain regions, but the role of adenosine in olfactory information processing has not been studied so far. We investigated the effects of adenosine on mitral cells, which are projection neurons of the olfactory bulb. Significant expression of A1 and A2A receptors was found in mitral cells, as demonstrated by in situ hybridization. Application of adenosine in acute olfactory bulb slices hyperpolarized mitral cells in wild-type but not in adenosine A1 receptor knockout mice. Adenosine-induced hyperpolarization was mediated by background K+ currents that were reduced by halothane and bupivacaine, which are known to inhibit two-pore domain K+ (K2P) channels. In mitral cells, electrical stimulation of axons of olfactory sensory neurons evoked synaptic currents, which can be considered as input signals, while spontaneous firing independent of sensory input can be considered as noise. Synaptic currents were not affected by adenosine, while adenosine reduced spontaneous firing, leading to an increase in the signal-to-noise ratio of mitral cell firing. Our findings demonstrate that A1 adenosine receptors activate two-pore domain K+ channels, which increases the signal-to-noise ratio of the input-output relationship in mitral cells and thereby modulates information processing in the olfactory bulb.
Collapse
Affiliation(s)
- Natalie Rotermund
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Svenja Winandy
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Timo Fischer
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Kristina Schulz
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Torsten Fregin
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Nadine Alstedt
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Melanie Buchta
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Janick Bartels
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Nanna Svartz Väg 2, Stockholm, 17177, Sweden
| | - Christian Lohr
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| | - Daniela Hirnet
- Division of Neurophysiology, Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany
| |
Collapse
|
49
|
Antipurinergic therapy for autism-An in-depth review. Mitochondrion 2017; 43:1-15. [PMID: 29253638 DOI: 10.1016/j.mito.2017.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022]
Abstract
Are the symptoms of autism caused by a treatable metabolic syndrome that traces to the abnormal persistence of a normal, alternative functional state of mitochondria? A small clinical trial published in 2017 suggests this is possible. Based on a new unifying theory of pathogenesis for autism called the cell danger response (CDR) hypothesis, this study of 10 boys, ages 5-14years, showed that all 5 boys who received antipurinergic therapy (APT) with a single intravenous dose of suramin experienced improvements in all the core symptoms of autism that lasted for 5-8weeks. Language, social interaction, restricted interests, and repetitive movements all improved. Two children who were non-verbal spoke their first sentences. None of these improvements were observed in the placebo group. Larger and longer studies are needed to confirm this promising discovery. This review introduces the concept of M2 (anti-inflammatory) and M1 (pro-inflammatory) mitochondria that are polarized along a functional continuum according to cell stress. The pathophysiology of the CDR, the complementary functions of M1 and M2 mitochondria, relevant gene-environment interactions, and the metabolic underpinnings of behavior are discussed as foundation stones for understanding the improvements in ASD behaviors produced by antipurinergic therapy in this small clinical trial.
Collapse
|
50
|
Abstract
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume. Glial calcium waves induced by neuron-derived ATP mediate functional hyperemia in the retina. Purinergic signaling contributes to the induction of Müller cell gliosis, for example, of cellular proliferation and downregulation of potassium channels, which are important for the homeostatic functions of Müller cells. Purinergic glial calcium waves may also promote the long-range propagation of gliosis and neuronal degeneration across the retinal tissue. The osmotic ATP release is inhibited under pathological conditions. Inhibition of the ATP release may result in osmotic Müller cell swelling and dysregulation of the water transport through the cells; both may contribute to the development of retinal edema. Suppression of the osmotic ATP release and upregulation of the ecto-apyrase (NTPDase1), which facilitate the extracellular degradation of ATP and the formation of adenosine, may protect neurons and photoreceptors from death due to overactivation of P2X receptors. Pharmacological inhibition of P2X7 receptors and stimulation of adenosine receptors may represent clinical approaches to prevent retinal cell death and dysregulated cell proliferation, and to treat retinal edema.
Collapse
Affiliation(s)
- Andreas Reichenbach
- 1 Paul Flechsig Institute of Brain Research, University of Leipzig , Leipzig, Germany
| | - Andreas Bringmann
- 2 Department of Ophthalmology and Eye Hospital, University of Leipzig , Leipzig, Germany
| |
Collapse
|