Ramelteon suppresses astrocytic senescence via MT1-cAMP axis to protect dopaminergic neurons
- 1Department of Pharmacy, Children's Hospital of Soochow University, Suzhou, China
- 2Department of Mental Health, Children's Hospital of Soochow University, Suzhou, Jiangsu, China
Abstract
IntroductionAstrocytic senescence is increasingly recognized as a critical contributor to the pathogenesis of Parkinson’s disease (PD). Ramelteon, a clinically approved MT1/MT2 melatonin receptor agonist, has demonstrated neuroprotective effects in various neurological disorders. However, whether Ramelteon can inhibit astrocytic senescence and the underlying mechanisms remain unknown.MethodsAn in vivo MPTP-induced mouse model of PD was used to evaluate the therapeutic potential of Ramelteon. An in vitro long-term culture-induced replicative senescence model (40 days in vitro, DIV) and MPP+-induced premature senescence model in primary astrocytes were employed. Immunoblotting, real-time quantitative PCR, immunofluorescence, SA-β-gal staining, and immunohistochemistry were performed to assess astrocytic senescence, dopaminergic neuronal survival, and motor function.ResultsRamelteon treatment significantly attenuated MPTP-induced dopaminergic neuronal loss in the substantia nigra compacta (SNc) and improved motor deficits in mice. In vitro, Ramelteon markedly suppressed both replicative and MPP+-induced astrocytic senescence, as evidenced by decreased p16Ink4a and SA-β-gal activity, restored LaminB1 expression, and reduced senescence-associated secretory phenotype (SASP) factors (IL-6, IL-1β, CXCL10, and MMP9). Mechanistically, knockdown of Mtnr1a (encoding MT1), but not Mtnr1b (encoding MT2), largely abolished the anti-senescence effects of Ramelteon. MT1 activation inhibited adenylate cyclase (AC) activity and reduced intracellular cyclic adenosine monophosphate (cAMP) levels. Notably, senescent astrocytes exhibited elevated cAMP levels, and the cAMP inhibitor SQ22536 mimicked while the cAMP analog dbcAMP reversed the anti-senescence effects of Ramelteon. Furthermore, Ramelteon reduced mitochondrial ROS (mitoROS) production in senescent astrocytes through MT1-cAMP signaling.DiscussionOur findings demonstrate that Ramelteon inhibits astrocytic senescence through MT1 receptor-mediated cAMP suppression and mitochondrial ROS reduction, thereby protecting DA neurons in a PD mouse model. This study identifies Ramelteon as a potential therapeutic agent for PD by suppressing astrocytic senescence through MT1 activation.
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BibTeX
@article{gu2026ramelteon,
title = {{Ramelteon suppresses astrocytic senescence via MT1-cAMP axis to protect dopaminergic neurons}},
author = {Chao Gu and Yajing Chen and Xiaohuan Du and Fang Li and Shuwei Yuan and Wenjing Wang and Ping Guo and Shikai Wang and Mei Wang},
journal = {Frontiers in Aging Neuroscience},
year = {2026},
month = oct,
doi = {10.3389/fnagi.2026.1974509},
url = {https://doi.org/10.3389/fnagi.2026.1974509},
note = {CC BY},
}
RIS
TY - JOUR
TI - Ramelteon suppresses astrocytic senescence via MT1-cAMP axis to protect dopaminergic neurons
AU - Chao Gu
AU - Yajing Chen
AU - Xiaohuan Du
AU - Fang Li
AU - Shuwei Yuan
AU - Wenjing Wang
AU - Ping Guo
AU - Shikai Wang
AU - Mei Wang
PY - 2026
DA - 2026/10/26
JO - Frontiers in Aging Neuroscience
DO - 10.3389/fnagi.2026.1974509
UR - https://doi.org/10.3389/fnagi.2026.1974509
AB - IntroductionAstrocytic senescence is increasingly recognized as a critical contributor to the pathogenesis of Parkinson’s disease (PD). Ramelteon, a clinically approved MT1/MT2 melatonin receptor agonist, has demonstrated neuroprotective effects in various neurological disorders. However, whether Ramelteon can inhibit astrocytic senescence and the underlying mechanisms remain unknown.MethodsAn in vivo MPTP-induced mouse model of PD was used to evaluate the therapeutic potential of Ramelteon. An in vitro long-term culture-induced replicative senescence model (40 days in vitro, DIV) and MPP+-induced premature senescence model in primary astrocytes were employed. Immunoblotting, real-time quantitative PCR, immunofluorescence, SA-β-gal staining, and immunohistochemistry were performed to assess astrocytic senescence, dopaminergic neuronal survival, and motor function.ResultsRamelteon treatment significantly attenuated MPTP-induced dopaminergic neuronal loss in the substantia nigra compacta (SNc) and improved motor deficits in mice. In vitro, Ramelteon markedly suppressed both replicative and MPP+-induced astrocytic senescence, as evidenced by decreased p16Ink4a and SA-β-gal activity, restored LaminB1 expression, and reduced senescence-associated secretory phenotype (SASP) factors (IL-6, IL-1β, CXCL10, and MMP9). Mechanistically, knockdown of Mtnr1a (encoding MT1), but not Mtnr1b (encoding MT2), largely abolished the anti-senescence effects of Ramelteon. MT1 activation inhibited adenylate cyclase (AC) activity and reduced intracellular cyclic adenosine monophosphate (cAMP) levels. Notably, senescent astrocytes exhibited elevated cAMP levels, and the cAMP inhibitor SQ22536 mimicked while the cAMP analog dbcAMP reversed the anti-senescence effects of Ramelteon. Furthermore, Ramelteon reduced mitochondrial ROS (mitoROS) production in senescent astrocytes through MT1-cAMP signaling.DiscussionOur findings demonstrate that Ramelteon inhibits astrocytic senescence through MT1 receptor-mediated cAMP suppression and mitochondrial ROS reduction, thereby protecting DA neurons in a PD mouse model. This study identifies Ramelteon as a potential therapeutic agent for PD by suppressing astrocytic senescence through MT1 activation.
SN - 1663-4365
ER -