Berberine exerts antidepressant effects in vivo and in vitro through the PI3K/AKT/CREB/BDNF signaling pathway

BACKGROUND

Depression, a global neuropsychiatric disorder, brings a serious burden to patients and society as its incidence continues to rise. Berberine is one of the main compounds of a variety of Chinese herbal medicines and has been shown to have multiple pharmacological effects. However, whether berberine can exert antidepressant effects in vivo and in vitro and its related mechanisms remain to be explored.

METHODS

The chronic restraint stress (CRS) method and corticosterone (CORT) were applied to simulate depression-like behavior in vivo and neuronal apoptosis in vitro, respectively. The antidepressant effects of berberine were evaluated by behavioral tests and changes in the content of monoamine neurotransmitters. Inflammatory cytokines were detected and immunofluorescence staining was used to observe the expression levels of apoptosis-related proteins. RT-qPCR and Western blot were used to examine the mRNA and protein expression (or phosphorylation) levels of biomarkers of the PI3K/AKT/CREB/BDNF signaling pathways.

RESULTS

Behavioral tests and levels of neurotransmitters proved that berberine could effectively ameliorate depression-like symptoms in CRS mice. Meanwhile, the results of ELISA and immunofluorescence staining showed that berberine could alleviate inflammatory status and reduce cell apoptosis in vivo and in vitro. Moreover, the changes of the PI3K/AKT/CREB/BDNF signaling pathway induced by CRS or CORT in mouse hippocampus or HT-22 cells were significantly reversed by berberine.

CONCLUSION

Our current study suggested that berberine could exert antidepressant effects in vitro and in vivo, which may be associated with the PI3K/AKT/CREB/BDNF signaling pathway.

Mailuoning oral liquid attenuates convalescent cerebral ischemia by inhibiting AMPK/mTOR-associated apoptosis and promoting CREB/BDNF-mediated neuroprotection

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke is divided into acute, subacute and convalescent phases according to the time of onset. Clinically, Mailuoning oral liquid (MLN O) is a traditional Chinese patent medicine for treating ischemic stroke. Previous studies have shown that MLN O could prevent acute cerebral ischemia-reperfusion. However, its underlying mechanism remains unclear.

AIM OF THE STUDY

To investigate the relationship between neuroprotection and apoptosis for clarifying MLN O mechanism in the recovery phase of ischemic stroke.

MATERIALS AND METHODS

We imitated stroke using middle cerebral artery occlusion/reperfusion (MCAO/R) in vivo and oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro models. The infarct volume, neurological deficit scores, HE staining, Nissl staining, TUNEL staining, immunohistochemistry, and Western blot were correspondingly performed to find pathological changes and detect neuronal apoptosis in rat cerebral cortex. The contents of LDH, Cyt-c, c-AMP and BDNF in rat plasma and cerebral cortex were detected by ELISA. Cell viability was measured by CCK8 assay. Cell morphology, Hoechst 33342 staining and Annexin-V-Alexa Fluor 647/PI staining were performed to assess neuronal apoptosis. The expression levels of proteins were evaluated by western blotting.

RESULTS

MLN O obviously reduced brain infarct volume and neurological deficit scores in MCAO rats. MLN O inhibited inflammatory cell infiltration and neuronal apoptosis, but promoted gliosis, neuronal survival, and neuroprotection in the cortical region of MCAO rats. Additionally, MLN O decreased the amount of LDH and cytochrome c, while increasing the expression of c-AMP in the plasma and ischemic cerebral cortex of MCAO rats, and promoting the expression of BDNF in the cortical tissue of MCAO rats. Besides, MLN O improved cell viability, restored cell morphology, while attenuating cell damage, inhibiting neuronal apoptosis following OGD/R in PC-12 cells. Moreover, MLN O inhibited apoptosis by suppressing the expression of pro-apoptotic-associated proteins, including Bax, cytochrome c, Cleaved caspase 3 and HIF-1α, whereas accelerating the expression of Bcl-2 in vivo and in vitro. Furthermore, MLN O inhibited the activity of AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR), but activated the signaling pathway of cAMP-response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) in MCAO rats and OGD/R-stimulated PC-12 cells.

CONCLUSIONS

These results demonstrated that MLN O inhibited AMPK/mTOR to affect apoptosis associated with mitochondria, leading to improve CREB/BDNF-mediated neuroprotection in the recovery period of ischemic stroke in vivo and in vitro.

Copper Induces Cognitive Impairment in Mice via Modulation of Cuproptosis and CREB Signaling

It has been reported that disordered Cu metabolism is associated with several neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). However, the underlying mechanism is still unclear. In this study, 4-week-old male mice were exposed to Cu by free-drinking water for three months. Then, the effects of Cu on cognitive functions in mice were tested by Morris water maze tests, and the potential mechanisms were investigated by the ELISA, immunochemistry, TUNEL, and Western blot tests. It was found that Cu exacerbates learning and memory impairment, and leads to Cu-overload in the brain and urine of mice. The results showed that Cu induces neuronal degeneration and oxidative damage, promotes the expression of apoptosis-related protein Bax, cuproptosis-related proteins FDX1 and DLAT and the proteotoxic stress marker HSP70, and decreases Fe-S cluster proteins. In addition, Cu affects the pre-synaptic and post-synaptic regulatory mechanisms through inhibiting the expression of PSD-95 and SYP. Cu also suppresses phosphorylation levels in CREB and decreases the expression of BDNF and TrkB in the mouse hippocampus. In conclusion, Cu might mediate cuproptosis, damage synaptic plasticity and inhibit the CREB/BDNF pathway to cause cognitive dysfunction in mice.

Double-blind, randomized, placebo-controlled pilot study of the phosphodiesterase-3 inhibitor cilostazol as an adjunctive to antidepressants in patients with major depressive disorder

AIMS

Cilostazol (CLS) has shown antidepressant effect in cardiovascular patients, post-stroke depression, and animal models through its neurotrophic and antiinflammatory activities. Consequently, we aimed to investigate its safety and efficacy in patients with MDD by conducting double-blind, randomized, placebo-controlled pilot study.

METHODS

80 participants with MDD (DSM-IV criteria) and Hamilton Depression Rating Scale (HDRS) score >20 were treated with CLS 50 mg or placebo twice daily plus escitalopram (ESC) 20 mg once daily for six weeks. Patients were evaluated by HDRS scores (weeks 0, 2, 4, and 6). Serum levels of CREB1, BDNF, 5-HT, TNF-α, NF- κB, and FAM19A5 were assessed pre- and post-treatment.

RESULTS

Co-administration of CLS had markedly decreased HDRS score at all-time points compared to the placebo group (p < 0.001). Early improvement, response, and remission rates after 6 weeks were significantly higher in the CLS group (90%, 90%, 80%, respectively) than in the placebo group (25%, 65%, 50% respectively) (p < 0.001). Moreover, the CLS group was superior to the placebo group in modulation of the measured neurotrophic and inflammatory biomarkers.

CONCLUSION

CLS is safe and effective short-term adjunctive therapy in patients with MDD with no other comorbid conditions. Trial registration ID:NCT04069819.

MiRNA-199a-5p targets WNT2 to regulate depression through the CREB/BDNF signaling in hippocampal neuron

INTRODUCTION

This study mainly investigated the role of miR-199a-5p in depression.

METHODS

qRT-PCR and western blotting were employed to detect the expressions of miR-199a-5p, CREB and BDNF. Sucrose preference test, forced swimming test, and tail suspension test were performed to evaluate depression-related symptoms. MTT assays and flow cytometry were used to examine the cell reproduction and apoptotic cells of hippocampal neuron.

RESULTS

The data demonstrated that the expression levels of miR-199a-5p in the cerebrospinal fluids and serums of depression patient and the hippocampus of chronic unpredictable mild stress (CUMS) mouse were significantly increased. However, the expressions of WNT2, p-CREB, and BDNF were inhibited. In addition, miR-199a-5p-inhibitor enhanced sucrose preferences of CUMS mouse and decreased immobile time in sucrose preference test and forced swimming test. Knockdown of WNT2 attenuated the effects of miR-199a-5p-inhibitor on cell reproduction and apoptotic cells of hippocampal neuron and the expression of WNT2, p-CREB, and BDNF.

CONCLUSION

MiR-199a-5p can target WNT2 to enhance the development of depression through regulation of the CREB/BDNF signaling.

TRIAL REGISTRATION

JNU-Hos-49284.

Black Bamboo Rhizome Extract Improves Cognitive Dysfunction by Upregulating the Expression of Hippocampal BDNF and CREB in Rats with Cerebral Ischaemia-Reperfusion Injury

INTRODUCTION

The study aimed to explore the effects of treatment with black bamboo rhizome extracts on learning and memory and determine the underlying mechanisms in rats with cerebral ischaemia-reperfusion injury.

METHODS

Sprague-Dawley rats were randomly divided into the following four groups: control, middle cerebral artery occlusion (MCAO), low-dose drug, and high-dose drug groups. Rats underwent MCAO using a suture method before drug treatment. Then, neurological impairment was assessed using the Longa scoring method, and triphenyl tetrazolium chloride staining was used to analyse the cerebral infarction area. The Elliott formula was used to calculate water content in the brain tissue. A Morris water maze (MWM) was used to assess changes in learning and memory abilities, and Western blotting was used to detect cyclic adenosine phosphate response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) expression in the hippocampus of MCAO rats.

RESULTS

After treatment with black bamboo rhizome extracts, the neurological dysfunction score was lower in the drug groups than in the MCAO group, and a significant difference was observed between the high-dose drug and MCAO groups (P<0.05). Additionally, the cerebral infarction area was significantly smaller in the drug groups than in the MCAO group (P<0.01), and the effect was more obvious in the high-dose drug group than in the low-dose drug group. There was also a significant difference in water content between the high-dose drug and MCAO groups, and cerebral oedema was significantly reduced in the high-dose drug group (P<0.05). In the MWM, the incubation period was significantly reduced, the number of platform crossings was significantly increased, and the search time was prolonged in the drug groups compared with those in the MCAO group (P<0.05). Moreover, the expression of BDNF and CREB was significantly increased in the drug groups compared to that in the MCAO group, and the increase was more obvious in the high-dose group than in the low-dose group (P<0.05).

DISCUSSION

Black bamboo rhizome extracts significantly improved cognitive dysfunction, reduced cerebral oedema, decreased the cerebral infarction area, and improved the neurological function score and learning and memory abilities in rats with cerebral ischaemia-reperfusion injury.

Chenodeoxycholic Acid Ameliorates AlCl3-Induced Alzheimer's Disease Neurotoxicity and Cognitive Deterioration via Enhanced Insulin Signaling in Rats

Insulin resistance is a major risk factor for Alzheimer’s disease (AD). Chenodeoxycholic acid (CDCA) and synthetic Farnesoid X receptor (FXR) ligands have shown promising outcomes in ameliorating insulin resistance associated with various medical conditions. This study aimed to investigate whether CDCA treatment has any potential in AD management through improving insulin signaling. Adult male Wistar rats were randomly allocated into three groups and treated for six consecutive weeks; control (vehicle), AD-model (AlCl₃ 50 mg/kg/day i.p) and CDCA-treated group (AlCl₃ + CDCA 90 mg/kg/day p.o from day 15). CDCA improved cognition as assessed by Morris Water Maze and Y-maze tests and preserved normal histological features. Moreover, CDCA lowered hippocampal beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and amyloid-beta 42 (Aβ₄₂). Although no significant difference was observed in hippocampal insulin level, CDCA reduced insulin receptor substrate-1 phosphorylation at serine-307 (pSer307-IRS1), while increased protein kinase B (Akt) activation, glucose transporter type 4 (GLUT4), peroxisome proliferator-activated receptor gamma (PPARγ) and glucagon-like peptide-1 (GLP-1). Additionally, CDCA activated cAMP response element-binding protein (CREB) and enhanced brain-derived neurotrophic factor (BDNF). Ultimately, CDCA was able to improve insulin sensitivity in the hippocampi of AlCl₃-treated rats, which highlights its potential in AD management.

Protective role of metformin against methamphetamine induced anxiety, depression, cognition impairment and neurodegeneration in rat: The role of CREB/BDNF and Akt/GSK3 signaling pathways

BACKGROUND

Methamphetamine is a neuro-stimulant with neurodegenerative effects, and ambiguous mechanism of action. Metformin is an antidiabetic agent with neuroprotective properties but not fully understood mechanisms. The present study investigated the molecular basis of metformin neuroprotection against methamphetamine-induced neurodegeneration.

BRIEF METHOD

Sixty adult male rats were randomly divided into six groups: group 1 (received normal saline), group 2 (received 10 mg/kg of methamphetamine) and groups 3, 4, 5 and 6 [received methamphetamine (10 mg/kg) plus metformin (50, 75, 100 and 150 mg/kg) respectively]. Elevated Plus Maze (EPM), Open Field Test (OFT), Forced Swim Test (FST), Tail Suspension Test (TST) and Morris Water Maze (MWM) were used to assess the level of anxiety, depression and cognition in experimental animals. Also animals' hippocampus were isolated and oxidative stress and inflammatory parameters and expression of total and phosphorylated forms of cAMP response element binding (CREB), brain-derived neurotrophic factor (BDNF), protein kinase B (Akt) and glycogen synthase kinase 3 (GSK3) proteins were evaluated by ELISA method.

RESULTS

According to the data obtained, methamphetamine caused significant depression, anxiety, motor activity disturbances and cognition impairment in experimental animals. Metformin, in all used doses, decreased methamphetamine induced behavioral disturbances. Also chronic administration of methamphetamine could increase malondialdehyde (MDA), tumor necrosis factor-Alpha (TNF-α) and interleukine-1 beta (IL-1β) in rats, while caused reduction of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) activities. Metformin, especially in high doses, could prevent these malicious effects of methamphetamine. Also Metformin could activate CREB (both forms), BDNF and Akt (both forms) proteins' expression and inhibited GSK3 (both forms) protein expression in methamphetamine treated rats.

SIGNIFICANCE

According to obtained data, metformin could protect the brain against methamphetamine-induced neurodegeneration probably by mediation of CREB/BDNF or Akt/GSK3 signaling pathways. These data suggested that CREB/BDNF or Akt/GSK3 signaling pathways may have a critical role in methamphetamine induced neurotoxicity and/or neuroprotective effects of metformin.

HIV-1 Protein Tat1-72 Impairs Neuronal Dendrites via Activation of PP1 and Regulation of the CREB/BDNF Pathway

Despite the success of combined antiretroviral therapy in recent years, the prevalence of human immunodeficiency virus (HIV)-associated neurocognitive disorders in people living with HIV-1 is increasing, significantly reducing the health-related quality of their lives. Although neurons cannot be infected by HIV-1, shed viral proteins such as transactivator of transcription (Tat) can cause dendritic damage. However, the detailed molecular mechanism of Tat-induced neuronal impairment remains unknown. In this study, we first showed that recombinant Tat (1-72 aa) induced neurotoxicity in primary cultured mouse neurons. Second, exposure to Tat_1-72 was shown to reduce the length and number of dendrites in cultured neurons. Third, Tat_1-72 (0-6 h) modulates protein phosphatase 1 (PP1) expression and enhances its activity by decreasing the phosphorylation level of PP1 at Thr320. Finally, Tat_1-72 (24 h) downregulates CREB activity and CREB-mediated gene (BDNF, c-fos, Egr-1) expression. Together, these findings suggest that Tat_1-72 might impair cognitive function by regulating the activity of PP1 and the CREB/BDNF pathway.

Topiramate via NMDA, AMPA/kainate, GABAA and Alpha2 receptors and by modulation of CREB/BDNF and Akt/GSK3 signaling pathway exerts neuroprotective effects against methylphenidate-induced neurotoxicity in rats

Chronic abuse of methylphenidate (MPH) often causes neuronal cell death. Topiramate (TPM) carries neuroprotective effects, but its exact mechanism of action remains unclear. In the present study, the role of various doses of TPM and its possible mechanisms, receptors and signaling pathways involved against MPH-induced hippocampal neurodegeneration were evaluated in vivo. Thus, domoic acid (DOM) was used as AMPA/kainate receptor agonist, bicuculline (BIC) as GABA_A receptor antagonist, ketamine (KET) as NMDA receptor antagonist, yohimbine (YOH) as α₂ adrenergic receptor antagonist and haloperidol (HAL) was used as dopamine D₂ receptor antagonist. Open field test (OFT) was used to investigate the disturbances in motor activity. Hippocampal neurodegenerative parameters were evaluated. Protein expressions of CREB/BDNF and Akt/GSK3 signaling pathways were also evaluated. Cresyl violet staining was performed to show and confirm the changes in the shape of the cells. TPM (70 and 100 mg/kg) reduced MPH-induced rise in lipid peroxidation, oxidized form of glutathione (GSSG), IL-1β and TNF-α levels, Bax expression and motor activity disturbances. In addition, TPM treatment increased Bcl-2 expression, the level of reduced form of glutathione (GSH) and the levels and activities of superoxide dismutase, glutathione peroxidase and glutathione reductase enzymes. TPM also inhibited MPH-induced hippocampal degeneration. Pretreatment of animals with DOM, BIC, KET and YOH inhibited TPM-induced neuroprotection and increased oxidative stress, neuroinflammation, neuroapoptosis and neurodegeneration while reducing CREB, BDNF and Akt protein expressions. Also pretreatment with DOM, BIC, KET and YOH inhibited TPM-induced decreases in GSK3. It can be concluded that the mentioned receptors by modulation of CREB/BDNF and Akt/GSK3 pathways, are involved in neuroprotection of TPM against MPH-induced neurodegeneration.

Comparative Studies on Behavioral, Cognitive and Biomolecular Profiling of ICR, C57BL/6 and Its Sub-Strains Suitable for Scopolamine-Induced Amnesic Models

Cognitive impairment and behavioral disparities are the distinctive baseline features to investigate in most animal models of neurodegenerative disease. However, neuronal complications are multifactorial and demand a suitable animal model to investigate their underlying basal mechanisms. By contrast, the numerous existing neurodegenerative studies have utilized various animal strains, leading to factual disparity. Choosing an optimal mouse strain for preliminary assessment of neuronal complications is therefore imperative. In this study, we systematically compared the behavioral, cognitive, cholinergic, and inflammatory impairments of outbred ICR and inbred C57BL/6 mice strains subject to scopolamine-induced amnesia. We then extended this study to the sub-strains C57BL/6N and C57BL/6J, where in addition to the above-mentioned parameters, their endogenous antioxidant levels and cAMP response-element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) protein expression were also evaluated. Compared with the ICR strain, the scopolamine-inflicted C57BL/6 strains exhibited a substantial reduction of spontaneous alternation and an approximately two-fold increase in inflammatory protein expression, compared to the control group. Among the sub-strains, scopolamine-treated C57BL/6N strains exhibited declined step-through latency, elevated acetylcholinesterase (AChE) activity and inflammatory protein expression, associated with reduced endogenous antioxidant levels and p-CREB/BDNF expression, compared to the control and tacrine-treated groups. This indicates that the C57BL/6N strains exhibit significantly enhanced scopolamine-induced neuronal impairment compared to the other evaluated strains.

Possible involvement of CREB/BDNF signaling pathway in neuroprotective effects of topiramate against methylphenidate induced apoptosis, oxidative stress and inflammation in isolated hippocampus of rats: Molecular, biochemical and histological evidences

Chronic abuse of methylphenidate (MPH) can cause serious neurotoxicity. The neuroprotective effects of topiramate (TPM) were approved, but its putative mechanism remains unclear. In current study the role of CREB/BDNF signaling pathway in TPM protection against methylphenidate-induced neurotoxicity in rat hippocampus was evaluated. 60 adult male rats were divided randomly into six groups. Groups received MPH (10mg/kg) only and concurrently with TPM (50mg/kg and 100mg/kg) and TPM (50 and 100mg/kg) only for 14 days. Open field test (OFT) was used to investigate motor activity. Some biomarkers of apoptotic, anti-apoptotic, oxidative, antioxidant and inflammatory factors were also measured in hippocampus. Expression of total (inactive) and phosphorylated (active) CREB and BDNF were also measured in gene and protein levels in dentate gyrus (DG) and CA1 areas of hippocampus. MPH caused significant decreases in motor activity in OFT while TPM (50 and 100mg/kg) inhibited MPH-induced decreases in motor activity. On the other hand, MPH caused remarkable increases in Bax protein level, lipid peroxidation, catalase activity, IL-1β and TNF-α levels in hippocampal tissue. MPH also caused significant decreases of superoxide dismutase, activity and also decreased CREB, in both forms, BDNF and Bcl-2 protein levels. TPM, by the mentioned doses, attenuated these effects and increased superoxide dismutase, glutathione peroxidase and glutathione reductase activities and also increased CREB, in both forms, BDNF and Bcl-2 protein levels and inhibited MPH induced increase in Bax protein level, lipid peroxidation, catalase activity, IL-1β and TNF-α levels. TPM also inhibited MPH induced decreases in cell number and changes in cell shapes in DG and CA1 areas. TPM can probably act as a neuroprotective agent against MPH induced neurotoxicity and this might have been mediated by CREB/BDNF signaling pathway.