Brain Research Bulletin最新文献

Background

Cerebral ischemia is characterized by its rapid onset and high rates of recurrence, morbidity, and mortality, with blood-brain barrier (BBB) permeability playing a vital role in brain injury. Therefore, it is important to understand the molecular mechanism which regulates the BBB during cerebral ischemia.

Materials and methods

An in vitro model of oxygen-glucose deprivation (OGD) and an in vivo model of cerebral ischemia/reperfusion (I/R) were constructed. PD-1 overexpression vectors and vectors containing si-RNA were transfected and injected into in vitro and in vivo models. Western blotting, real-time quantitative PCR (qPCR), immunofluorescence (IF) analysis, and immunohistochemical staining were employed to evaluate the expression levels of programmed cell death-1 (PD-1), microglia M1 and M2 biomarkers, and tight junction proteins. Flow cytometry and ELISA were used to measure the levels of pro-inflammatory cytokines. The BBB permeability of brain tissues was evaluated by Evans blue dye (EBD) extravasation and transendothelial electrical resistance (TEER). Brain water content was measured to assess the extent of inflammatory exudation. The infarct volume and neurological severity score (NSS) were used to assess the severity of brain injury. Brain cell apoptosis was assessed by the TUNEL assay and hematoxylin-eosin (H&E) staining.

Results

PD-1 helped to convert the microglia M1 phenotype to the M2 phenotype and to reduce BBB permeability both in vitro and in vivo. Overexpression of PD-1 promoted a shift of the M1 phenotype to the M2 phenotype and reduced BBB permeability via the ERK and p38 MAPK signaling pathways. PD-1 reduced inflammatory exudation, BBB permeability, cell apoptosis, and brain injury in vivo.

Conclusion

Our present study verified that PD-1 exerts an anti-inflammatory effect by converting the microglia M1 phenotype to the M2 phenotype, reducing BBB permeability, and thereby relieves brain injury caused by cerebral ischemia. PD-1 is potential therapeutic target for brain injury caused by cerebral ischemia.

Background

G protein-coupled receptor 68 (GPR68), an orphan receptor, has emerged as a promising therapeutic target for mitigating neuronal inflammation and oxidative damage. This study explores the protective mechanisms of GPR68 in cerebral ischemia-reperfusion injury (CIRI).

Methods

An in vivo middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was established. Mice received intraperitoneal injections of Ogerin, a selective GPR68 agonist. In vitro, GPR68 was overexpressed in SH-SY5Y and HMC3 cells, and the effects of oxygen-glucose deprivation/reperfusion (OGD/R) on cell viability were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and flow cytometry.

Results

The expression of GPR68 was suppressed in cells subjected to OGD/R treatment, whereas its upregulation conferred protection to SH-SY5Y and HMC3 cells. In vivo, levels of GPR68 were reduced in brain tissues affected by MCAO/R, correlating with oxidative stress, inflammation, and neurological damage. Treatment with a GPR68 agonist decreased brain infarction, apoptosis, and dysregulated gene expression induced by MCAO/R. Mechanistically, GPR68 agonist treatment may inhibit the activation of the NF-κB/Hif-1α pathway, thereby reducing oxidative and inflammatory responses and enhancing protection against CIRI.

Conclusions

This study confirms that the GPR68/NF-κB/Hif-1α axis modulates apoptosis, inflammation, and oxidative stress in CIRI, indicating that GPR68 is a potential therapeutic target for CIRI.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder distinguished by gradual depletion of motor neurons. RNA binding motif protein 5 (RBM5), an abundantly expressed RNA-binding protein, plays a critical role in the process of cellular death. However, little is known about the role of RBM5 in the pathogenesis of ALS. Here, we found that RBM5 was upregulated in ALS hSOD1^G93A-NSC34 cell models and hSOD1^G93A mice due to a reduction of miR-141–5p. The upregulation of RBM5 increased the apoptosis of motor neurons by inhibiting Rac1-mediated neuroprotection. In contrast, genetic knockdown of RBM5 rescued motor neurons from hSOD1^G93A-induced degeneration by activating Rac1 signaling. The neuroprotective effect of RBM5-knockdown was significantly inhibited by the Rac1 inhibitor, NSC23766. These findings suggest that RBM5 could potentially serve as a therapeutic target in ALS by activating the Rac1 signalling.

Background

Imagine if our brains could unconsciously predict future events. This study explores this concept, presenting evidence for an inherent 'foreseeing' ability, termed anomalous cognition (AC). We introduce a new experimentally verifiable approach to explain anomalous information anticipation (AIA), a type of AC, based on an innovative, quantum-like model of implicit learning, grounded in Nonlocal Plasticity Theory (NPT).

Methods

Our research involved 203 participants using methods such as continuous flash suppression, random dot motion, and advanced 3D EEG neuroimaging, along with IBM quantum random event generators for precise measurements across 144 trials. These trials tested contingencies between undetectable sensory stimuli and dot movements, focusing on participants' prediction abilities. The design conditions were strictly experimental, violating fundamental classical learning principles, particularly reflex conditioning. If these principles were immutable, their violation would prevent any systematic behavioral changes, resulting in random responses. This violation was implemented through two quantum physics concepts: the mathematical principle of nonlocality and entanglement.

Results

Despite the sensory stimulus being inaccessible, our results showed a significant prediction between the contingencies and an increase in AIA accuracy, with explained variances between 25 % and 48 %. EEG findings supported this, showing a positive link between brain activity in specific regions and AIA success. Electrochemical activations were detected in the posterior occipital cortex, the intraparietal sulcus, and the medial temporal gyri. AIA hits exceeded the threshold value corresponding to one standard deviation above the expected mean, showing moderate effect sizes in the experimental group (Cohen’s d = 0.461). Analyzing the learning curve using the derivation technique, we identified the acceleration point of the wave function, indicating systematic implicit learning. This result showed that from repetition 63 onwards, AIA hits increased significantly.

Conclusions

The results suggest that, despite violating fundamental classical learning principles, cognitive processes produced changes in participants' responses susceptible to neuromodulation, considering quantum physics principles of nonlocality and entanglement (both present in NPT). We discuss (a) why the priming effect does not explain the significant results; (b) the potential discovery of a new form of quantum-like implicit learning, which could scientifically resolve phenomena associated with anomalous cognitions (e.g., AIA); and (c) future research directions, including potential applications and clinical impact.

Objective

This study aimed to further elucidate the mechanism of ginsenoside Rg1 in the treatment of cerebral ischemia-reperfusion.

Methods

In this study, we observed the apoptosis of RM cells (microglia) after oxygen-glucose deprivation/reoxygenation (OGD/R) modeling before and after Rg1 administration, changes in mitochondrial membrane potential, changes in the content of Reactive oxygen species (ROS) and inflammatory vesicles NLR Family Pyrin Domain Containing 3 (NLRP3), and the expression levels of autophagy-related proteins, inflammatory factors, and apoptosis proteins. We further examined the pathomorphological changes in brain tissue, neuronal damage, changes in mitochondrial morphology and mitochondrial structure, and the autophagy-related proteins, inflammatory factors, and apoptosis proteins expression levels in CI/RI rats before and after administration of Rg1 in vivo experiments.

Results

In vitro experiments showed that Rg1 induced mitochondrial autophagy, decreased mitochondrial membrane potential, and reduced ROS content thereby inhibiting NLRP3 activation, decreasing secretion of inflammatory factors and RM cell apoptosis by regulating the PTEN induced putative kinase 1(Pink1) /Parkin signaling pathway. In vivo experiments showed that Rg1 induced mitochondrial autophagy, inhibited NLRP3 activation, improved inflammatory response, and reduced apoptosis by regulating the Pink1/Parkin signaling pathway, and Rg1 significantly reduced the area of cerebral infarcts, improved the pathological state of brain tissue, and attenuated the neuronal damage, thus improving cerebral ischemia/reperfusion injury in rats.

Conclusion

Our results suggest that ginsenoside Rg1 can ameliorate cerebral ischemia-reperfusion injury by modulating Pink1/ Parkin-mediated mitochondrial autophagy in microglia and inhibiting microglial NLRP3 activation.

Background

Immune dysregulation can play a role in depression pathophysiology, and immunological antagonists can improve depressive symptoms in treatment-resistant bipolar depression (TRD) patients according to studies.

Objective

To evaluate the anti-depressant effects of the anti-inflammatory drug, pentoxifylline (PTX) in TRD bipolar I/II adult subjects.

Methods

This 12-week, randomized, double-blind, placebo-controlled, parallel-group trial of 60 participants was conducted at Hawler Psychiatric Hospital and Private Clinic in Erbil, Iraq. Participants were confirmed as being qualified for bipolar I/II depression based on DSM-5 criteria. Data were analyzed using modified intent-to-treat analysis.

Results

There were no significant differences between the two groups in Hamilton Rating Scale for Depression-17 (HAM-D-17) scores (χ²=1.9, P =.48) or a significant time × treatment interaction (χ²=7.1, P=.54). Nevertheless, a significant effect of time was observed with both groups’ reduction in HAM-D-17 scores from the start to the endpoint (χ²= 2.11, P=.002). Besides, a significant time × treatment × CRP interaction was found (χ²=3.1, P=0.016), where there was more reduction in HAM-D-17 score in PTX-treated subjects with CRP> 7.1 mg/L. The response rate difference between PTX and the placebo group did not reach a significance level (χ²=0.84, p=0.43). Furthermore, serum concentrations of TNF-α, CRP, and IL-6 significantly reduced at week 12 in the PTX group (P=.007,.04, and <.001, respectively).

Conclusion

The current proof of concept study found that in terms of overall anti-depressant effectiveness in bipolar patients with TRD, PTX is not superior to placebo. However, it may improve depressive mood in a subpopulation of subjects with a higher pretreatment inflammatory profile.

Current clinical practice primarily relies on surgical intervention to remove hematomas in patients with intracerebral hemorrhage (ICH), given the lack of effective drug therapies. Previous research indicates that simvastatin (SIM) may enhance hematoma absorption and resolution in the acute phase of ICH, though the precise mechanisms remain unclear. Recent findings have highlighted the glymphatic system (GS) as a crucial component in intracranial cerebrospinal fluid circulation, playing a significant role in hematoma clearance post-ICH. This study investigates the link between SIM efficacy in hematoma resolution and the GS. Our experimental results show that SIM alleviates GS damage in ICH-induced rats, resulting in improved outcomes such as reduced brain edema, neuronal apoptosis, and degeneration. Further analysis reveals that SIM's effects are mediated through the VEGF-C/VEGFR3/PI3K-Akt pathway. This study advances our understanding of SIM's mechanism in promoting intracranial hematoma clearance and underscores the potential of targeting the GS for ICH treatment.

Background

Progressive supranuclear palsy (PSP) is characterized by the presence of hyperphosphorylated and misfolded tau aggregates in neurons and glia. Recent studies have illuminated the prion-like cell-to-cell propagation of tau via exosomes. Recognizing the potential significance of excretion through urine as a crucial pathway for eliminating pathological tau from the central nervous system, this study aimed to investigate whether exosomes derived from the urine of PSP-Richardson's syndrome (PSP-RS) patients can elicit tau pathology and PSP-like symptoms in mice.

Methods

Urinary exosomes obtained from PSP-RS patients and normal controls (NCs) were stereotactically injected into the bilateral globus pallidus of mouse brains. Behavioral analyses were conducted every 3 months post-injection. After 6 months, mice were sacrificed for pathological evaluation.

Results

Elevated levels of phosphorylated tau and neural cell markers were observed in urinary exosomes from PSP-RS patients compared to NCs. At the 6-month mark post-injection, tau inclusions were evident in the brains of mice receiving urinary exosomes from PSP-RS patients, with widespread distribution in both injection sites and distant brain regions (cortex, hippocampus, and substantia nigra). Tau pathology manifested in neurons and astrocytes. Moreover, mice injected with urinary exosomes from PSP-RS patients exhibited impaired motor coordination and balance, mirroring PSP motor symptoms.

Conclusion

Our findings indicate that urinary exosomes from PSP-RS patients can induce tau pathology and trigger PSP-like motor symptoms in mice. This leads to the hypothesis that exosomes may play a role in the pathogenesis of PSP.

Cannabidiol (CBD) is a non-psychoactive drug extracted from marijuana. It is well established that CBD attenuates the reinforcing effects of drugs of abuse, although its mechanism of action is not fully understood. The current study tries to clarify the role of D1-like dopamine receptors (D1R) in the ventral tegmental area (VTA) in the inhibitory effects of the CBD on the acquisition and expression of methamphetamine (METH)-conditioned place preference (CPP). In the CPP training, adult male Wistar rats were conditioned with subcutaneous administration of METH (1 mg/kg) for five days. Three groups of animals were treated with multiple doses of SCH23390 (as a D1R antagonist; 0.25, 1, and 4 μg/0.3 μl saline) in the VTA, respectively, before intracerebroventricular (ICV) injection of CBD (10 μg/5 μl DMSO) in the acquisition phase. In the second experiment of the study, rats received SCH23390 in the VTA before ICV administration of CBD (50 μg/5 μl DMSO) in the expression of METH CPP. Here, the current study demonstrated that CBD inhibits the acquisition and expression of METH CPP, while microinjection of D1R antagonists (1 and 4 μg) into the VTA significantly reduced CBD’s suppressive effect on the acquisition and expression of METH place preference. Furthermore, this research demonstrated that either SCH23390 or CBD alone does not lead to place preference in the CPP paradigm. Based on these data, this study suggests that pharmacological manipulations of D1R may alter the CBD’s effect on METH-conditioned preference.