β-Arrestin2-biased Drd2 agonist UNC9995 alleviates astrocyte inflammatory injury via interaction between β-arrestin2 and STAT3 in mouse model of depression

Abstract

Background Major depressive disorder (MDD) is a prevalent and devastating psychiatric illness. Unfortunately, the current therapeutic practice, generally depending on the serotonergic system for drug treatment is unsatisfactory and shows intractable side effects. Multiple evidence suggests that dopamine (DA) and dopaminergic signals associated with neuroinflammation are highly involved in the pathophysiology of depression as well as in the mechanism of antidepressant drugs, which is still in the early stage of study and well worthy of investigation. Methods We established two chronic stress models, including chronic unpredictable mild stress (CUMS), and chronic social defeat stress (CSDS), to complementarily recapitulate depression-like behaviors. Then, hippocampal tissues were used to detect inflammation-related molecules and signaling pathways. Pathological changes in depressive mouse hippocampal astrocytes were examined by RNA sequencing. After confirming the dopamine receptor 2 (Drd2)/β-arrestin2 signaling changes in the depressive mice brain, we then established the depressive mouse model using the β-arrestin2 knockout mice or administrating the β-arrestin2-biased Drd2 agonist to investigate the roles. Label-free mass spectrometry was used to identify the β-arrestin2-binding proteins as the underlying mechanisms. We modeled neuroinflammation with interleukin-6 (IL-6) and corticosterone treatment and characterized astrocytes using multiple methods including cell viability assay, flow cytometry, and confocal immunofluorescence. Results Drd2-biased β-arrestin2 pathway is significantly changed in the progression of depression, and genetic deletion of β-arrestin2 aggravates neuroinflammation and depressive-like phenotypes. Mechanistically, astrocytic β-arrestin2 retains STAT3 in the cytoplasm by structural combination with STAT3, therefore, inhibiting the JAK–STAT3 pathway-mediated inflammatory activation. Furtherly, pharmacological activation of Drd2/β-arrestin2 pathway by UNC9995 abolishes the inflammation-induced loss of astrocytes and ameliorates depressive-like behaviors in mouse model for depression. Conclusions Drd2/β-arrestin2 pathway is a potential therapeutic target for depression and β-arrestin2-biased Drd2 agonist UNC9995 is identified as a potential anti-depressant strategy for preventing astrocytic dysfunctions and relieving neuropathological manifestations in mouse model for depression, which provides insights for the therapy of depression.

Loss of β-arrestin2 aggravated condylar cartilage degeneration at the early stage of temporomandibular joint osteoarthritis

“…Additionally, we showed that in the absence of β-arrestin2, the apoptosis of chondrocytes was increased and the autophagic process was even more activated. Therefore, our results proved a protective role of β-arrestin2 in preventing apoptosis and autophagy, which is consistent with a previous study which demonstrated that the depletion of β-arrestin2 aggravates apoptosis of astrocytes stimulated by IL-6 [ 32 ]. In contrast, another study showing that β-arrestin2 depletion alleviated cell apoptosis by downregulating GRP78-ATF6-CHOP apoptosis signaling [ 33 ], which is contrary to our findings.…”

Loss of β-arrestin2 aggravated condylar cartilage degeneration at the early stage of temporomandibular joint osteoarthritis

“…Additionally, we showed that in the absence of β-arrestin2, the apoptosis of chondrocytes was increased and the autophagic process was even more activated. Therefore, our results proved a protective role of β-arrestin2 in preventing apoptosis and autophagy, which is consistent with a previous study which demonstrated that the depletion of β-arrestin2 aggravates apoptosis of astrocytes stimulated by IL-6 [24]. In contrast, another study showing that β-arrestin2 depletion alleviated cell apoptosis by downregulating GRP78-ATF6-CHOP apoptosis signaling [25], which is contrary to our ndings.…”

“…All utilized mice were maintained on a C57/BL6 background. All mice were housed in a temperature (22)(23)(24)(25)•C) and humidity-controlled (50% ± 10%) environment with a 12 h light/dark cycle.…”

The antidepressive mechanism of Longya Lilium combined with Fluoxetine in mice with depression-like behaviors

“…This has led to an investigation of the use of anti-inflammatory drugs as potential antidepressants 10 . Notably, the chronic unpredictable mild stress (CUMS) model, as a prime example, has been widely recognized to mimic depression-like disorders in which animals are exposed to continuous unpredictable micro stress for prolonged periods 11 . This model develops representations of depression, such as stress-induced aphasia and apathy 12 .…”