The Role of PI3K/Akt and ERK in Neurodegenerative Disorders

Cuscuta chinensis Lam. Flavonoids (CCLF) alleviate the symptoms of sepsis-associated encephalopathy via PI3K/Nrf2 pathway

Sepsis-associated encephalopathy (SAE) frequently encounters patients who are in intensive care units and ∼70% of patients with severe systemic infection. However, due to the unclear pathological mechanisms of SAE, the desease-modifying drug is still lack. Here, we aimed to explore whether the flavonoid components extracted from CCL (CCLF) seeds possess protective effects on SAE animals, and systematically evaluate the transcriptomic alteration (in the hippocampus) after CCLF treatment on SAE animals employing RNA sequencing. We observed that CCLF improved the brain's learning and memory abilities and the structural integrity of BBB using cecal ligation and puncture (CLP)-induced SAE animal models, evaluated by behavioral test and tissue examination of animals respectively. RNA sequencing results showed that CCLF treatment reverses SAE-induced transcriptomic alteration in the hippocampus. Moreover, CCLF also dramatically relieved inflammatory (such as TNF-α, IL-2, and IL-6) and oxidative (MDA and SOD activity) stresses, and inhibited SAE-induced neuron apoptosis in brain tissues. More importantly, CCLF restored the PI3K/AKT signaling pathway and then induced the Nrf2 nuclear translocation to drive HO-1 expression both in vitro and in vivo. LY294002, an inhibitor of PI3K, obviously blocked CCLF's functions on anti-apoptosis, anti-inflammation, and anti-oxidation in vivo, demonstrating that CCLF achieves its bioactivities in a PI3K/AKT signaling dependent manner. Altogether, CCLF exhibits remarkable neuro-protective function and may be a promising candidate for further clinical trials for SAE treatment.

Transsynaptic degeneration of ventral horn motor neurons exists but plays a minor role in lower motor system dysfunction in acute ischemic rats

BACKGROUND

As a leading cause of mortality and long-term disability, acute ischemic stroke can produce far-reaching pathophysiological consequences. Accumulating evidence has demonstrated abnormalities in the lower motor system following stroke, while the existence of Transsynaptic degeneration of contralateral spinal cord ventral horn (VH) neurons is still debated.

METHODS

Using a rat model of acute ischemic stroke, we analyzed spinal cord VH neuron counts contralaterally and ipsilaterally after stroke with immunofluorescence staining. Furthermore, we estimated the overall lower motor unit abnormalities after stroke by simultaneously measuring the modified neurological severity score (mNSS), compound muscle action potential (CMAP) amplitude, repetitive nerve stimulation (RNS), spinal cord VH neuron counts, and the corresponding muscle fiber morphology. The activation status of microglia and extracellular signal-regulated kinase 1/2 (ERK 1/2) in the spinal cord VH was also assessed.

RESULTS

At 7 days after stroke, the contralateral CMAP amplitudes declined to a nadir indicating lower motor function damage, and significant muscle disuse atrophy was observed on the same side; meanwhile, the VH neurons remained intact. At 14 days after focal stroke, lower motor function recovered with alleviated muscle disuse atrophy, while transsynaptic degeneration occurred on the contralateral side with elevated activation of ERK 1/2, along with the occurrence of neurogenic muscle atrophy. No apparent decrement of CMAP amplitude was observed with RNS during the whole experimental process.

CONCLUSIONS

This study offered an overview of changes in the lower motor system in experimental ischemic rats. We demonstrated that transsynaptic degeneration of contralateral VH neurons occurred when lower motor function significantly recovered, which indicated the minor role of transsynaptic degeneration in lower motor dysfunction during the acute and subacute phases of focal ischemic stroke.

PI3K/AKT signaling activation by roflumilast ameliorates rotenone-induced Parkinson's disease in rats

Parkinson's disease (PD) is the second most common progressive age-related neurodegenerative disorder. Paramount evidence shed light on the role of PI3K/AKT signaling activation in the treatment of neurodegenerative disorders. PI3K/AKT signaling can be activated via cAMP-dependent pathways achieved by phosphodiesterase 4 (PDE4) inhibition. Roflumilast is a well-known PDE4 inhibitor that is currently used in the treatment of chronic obstructive pulmonary disease. Furthermore, roflumilast has been proposed as a favorable candidate for the treatment of neurological disorders. The current study aimed to unravel the neuroprotective role of roflumilast in the rotenone model of PD in rats. Ninety male rats were allocated into six groups as follows: control, rotenone (1.5 mg/kg/48 h, s.c.), L-dopa (22.5 mg/kg, p.o), and roflumilast (0.2, 0.4 or 0.8 mg/kg, p.o). All treatments were administrated for 21 days 1 h after rotenone injection. Rats treated with roflumilast showed an improvement in motor activity and coordination as well as preservation of dopaminergic neurons in the striatum. Moreover, roflumilast increased cAMP level and activated the PI3K/AKT axis via stimulation of CREB/BDNF/TrkB and SIRT1/PTP1B/IGF1 signaling cascades. Roflumilast also caused an upsurge in mTOR and Nrf2, halted GSK-3β and NF-ĸB, and suppressed FoxO1 and caspase-3. Our study revealed that roflumilast exerted neuroprotective effects in rotenone-induced neurotoxicity in rats. These neuroprotective effects were mediated via the crosstalk between CREB/BDNF/TrkB and SIRT1/PTP1B/IGF1 signaling pathways which activates PI3K/AKT trajectory. Therefore, PDE4 inhibition is likely to offer a reliable persuasive avenue in curing PD via PI3K/AKT signaling activation.

Hyperbaric Oxygen Therapy Attenuated the Motor Coordination and Cognitive Impairment of Polyglutamine Spinocerebellar Ataxia SCA17 Mice

Spinocerebellar ataxias (SCAs) are a large and diverse group of autosomal-dominant neurodegenerative diseases. No drugs have been approved for these relentlessly progressive and fatal SCAs. Our previous studies indicate that oxidative stress, neuroinflammation, and neuronal apoptosis are elevated in the SCA17 mice, which are the main therapeutic targets of hyperbaric oxygen treatment (HBOT). HBOT is considered to be an alternative and less invasive therapy for SCAs. In this study, we evaluated the HBOT (2.2 ATA for 14 days) effect and the persistence for the management of SCA17 mice and their wild-type littermates. We found HBOT attenuated the motor coordination and cognitive impairment of SCA17 mice and which persisted for about 1 month after the treatment. The results of several biochemistry and liver/kidney hematoxylin and eosin staining show the HBOT condition has no obvious toxicity in the mice. Immunostaining analyses show that the neuroprotective effect of HBOT could be through the promotion of BDNF production and the amelioration of neuroinflammation. Surprisingly, HBOT executes different effects on the male and female SCA17 mice, including the reduction of neuroinflammation and activation of CaMKII and ERK. This study suggests HBOT is a potential alternative therapeutic treatment for SCA17. Accumulated findings have revealed the similarity in disease pathomechanisms and possible therapeutic strategies in polyQ diseases; therefore, HBOT could be an optional treatment as well as the other polyQ diseases.

GDF1 ameliorates cognitive impairment induced by hearing loss

Hearing loss is associated with an increased risk of Alzheimer disease (AD). However, the mechanisms of hearing loss promoting the onset of AD are poorly understood. Here we show that hearing loss aggravates cognitive impairment in both wild-type mice and mouse models of AD. Embryonic growth/differentiation factor 1 (GDF1) is downregulated in the hippocampus of deaf mice. Knockdown of GDF1 mimics the detrimental effect of hearing loss on cognition, while overexpression of GDF1 in the hippocampus attenuates the cognitive impairment induced by deafness. Strikingly, overexpression of GDF1 also attenuates cognitive impairment in APP/PS1 transgenic mice. GDF1 activates Akt, which phosphorylates asparagine endopeptidase and inhibits asparagine endopeptidase-induced synaptic degeneration and amyloid-β production. The expression of GDF1 is downregulated by the transcription factor CCAAT-enhancer binding protein-β. These findings indicate that hearing loss could promote AD pathological changes by inhibiting the GDF1 signaling pathway; thus, GDF1 may represent a therapeutic target for AD.

Human Glial Cells as Innovative Targets for the Therapy of Central Nervous System Pathologies

In vitro and preclinical in vivo research in the last 35 years has clearly highlighted the crucial physiopathological role of glial cells, namely astrocytes/microglia/oligodendrocytes and satellite glial cells/Schwann cells in the central and peripheral nervous system, respectively. Several possible pharmacological targets to various neurodegenerative disorders and painful conditions have therefore been successfully identified, including receptors and enzymes, and mediators of neuroinflammation. However, the translation of these promising data to a clinical setting is often hampered by both technical and biological difficulties, making it necessary to perform experiments on human cells and models of the various diseases. In this review we will, therefore, summarize the most relevant data on the contribution of glial cells to human pathologies and on their possible pharmacological modulation based on data obtained in post-mortem tissues and in iPSC-derived human brain cells and organoids. The possibility of an in vivo visualization of glia reaction to neuroinflammation in patients will be also discussed.

Metabolomics-Based Effects of a Natural Product on Remyelination After Cerebral Ischemia Injury Via GABABR-pCREB-BDNF Pathway

BACKGROUND

Yi-Qi-Tong-Luo Granules (YQTLs) is a natural compound of Traditional Chinese Medicine authorized by China Food and Drug Administration (CFDA). These granules are employed in the convalescent stage of cerebral infarction and render notable clinical efficacy. This study aims to uncover the underlying mechanisms of YQTLs on remyelination after cerebral ischemia injury.

MATERIALS AND METHODS

We established cerebral ischemia model in rats using microsphere-induced multiple cerebral infarction (MCI). We evaluated the pharmacological effects of YQTLs on MCI rats, through Morri's water maze test, open field test, hematoxylin and eosin staining, and glycine silver immersion. We employed liquid chromatography mass spectrometry metabolomics to identify differential metabolites. Enzyme-linked immunosorbent assay was utilized to measure the release of neurotrophins, while immunofluorescence staining was used to assess oligodendrocyte precursor cells differences and myelin regeneration. We used Western blotting to validate the protein expression of remyelination-associated signaling pathways.

RESULTS

YQTLs significantly improves cognitive function following cerebral ischemia injury. Pathological tissue staining revealed that YQTLs administration inhibits neuronal denaturation and neurofibrillary tangles. We identified 141 differential metabolites among the sham, MCI, and YQTLs-treated MCI groups. Among these metabolites, neurotransmitters were identified, and notably, gamma-aminobutyric acid (GABA) showed marked improvement in the YQTLs group. The induction of neurotrophins, such as brain-derived neurotrophic factor (BDNF) and PDGFAA, upregulation of olig2 and MBP expression, and promotion of remyelination were evident in YQTLs-treated MCI groups. Gamma-aminobutyric acid B receptors (GABABR), pERK/extracellular regulated MAP kinase, pAKT/protein kinase B, and pCREB/cAMP response element-binding were upregulated following YQTLs treatment.

CONCLUSION

YQTLs enhance the binding of GABA to GABABR, thereby activating the pCREB/BDNF signaling pathway, which in turn increases the expression of downstream myelin-associated proteins and promotes remyelination and cognitive function.

ERK pathway agonism for cancer therapy: evidence, insights, and a target discovery framework

At least 40% of human cancers are associated with aberrant ERK pathway activity (ERKp). Inhibitors targeting various effectors within the ERKp have been developed and explored for over two decades. Conversely, a substantial body of evidence suggests that both normal human cells and, notably to a greater extent, cancer cells exhibit susceptibility to hyperactivation of ERKp. However, this vulnerability of cancer cells remains relatively unexplored. In this review, we reexamine the evidence on the selective lethality of highly elevated ERKp activity in human cancer cells of varying backgrounds. We synthesize the insights proposed for harnessing this vulnerability of ERK-associated cancers for therapeutical approaches and contextualize these insights within established pharmacological cancer-targeting models. Moreover, we compile the intriguing preclinical findings of ERK pathway agonism in diverse cancer models. Lastly, we present a conceptual framework for target discovery regarding ERKp agonism, emphasizing the utilization of mutual exclusivity among oncogenes to develop novel targeted therapies for precision oncology.

Engagement of AKT and ERK signaling pathways facilitates infection of human neuronal cells with West Nile virus

West Nile virus (WNV) is an important neurotropic virus that accounts for the emergence of human arboviral encephalitis and meningitis. The interaction of WNV with signaling pathways plays a key role in controlling WNV infection. We have investigated the roles of the AKT and ERK pathways in supporting WNV propagation and modulating the inflammatory response following WNV infection. WNV established a productive infection in neuronal cell lines originated from human and mouse. Expression of IL-11 and TNF-α was markedly up-regulated in the infected human neuronal cells, indicating elicitation of inflammation response upon WNV infection. WNV incubation rapidly activated signaling cascades of AKT (AKT-S6-4E-BP1) and ERK (MEK-ERK-p90RSK) pathways. Treatment with AKT inhibitor MK-2206 or MEK inhibitor U0126 abrogated WNV-induced AKT or ERK activation. Strong activation of AKT and ERK signaling pathways could be detectable at 24 h after WNV infection, while such activation was abolished at 48 h post infection. U0126 treatment or knockdown of ERK expression significantly increased WNV RNA levels and viral titers and efficiently decreased IL-11 production induced by WNV, suggesting the involvement of ERK pathway in WNV propagation and IL-11 induction. MK-2206 treatment enhanced WNV RNA replication accompanied with a moderate decrease in IL-11 production. These results demonstrate that engagement of AKT and ERK signaling pathways facilitates viral infection and may be implicated in WNV pathogenesis.

A Protective Role of Canonical Wnt/β-Catenin Pathway in Pathogenic Bacteria-Induced Inflammatory Responses

Inflammation is a complex host defensive response against various disease-associated pathogens. A baseline extent of inflammation is supposed to be tightly associated with a sequence of immune-modulated processes, resulting in the protection of the host organism against pathogen invasion; however, as a matter of fact is that an uncontrolled inflammatory cascade is the main factor responsible for the host damage, accordingly suggesting a significant and indispensable involvement of negative feedback mechanism in modulation of inflammation. Evidence accumulated so far has supported a repressive effect of the canonical Wnt/β-catenin pathway on microbial-triggered inflammation via diverse mechanisms, although that consequence is dependent on the cellular context, types of stimuli, and cytokine environment. It is of particular interest and importance to comprehend the precise way in which the Wnt/β-catenin pathway is activated, due to its essential anti-inflammatory properties. It is assumed that an inflammatory milieu is necessary for initiating and activating this signaling, implying that Wnt activity is responsible for shielding tissues from overwhelming inflammation, thus sustaining a balanced physiological condition against bacterial infection. This review gathers the recent efforts to elucidate the mechanistic details through how Wnt/β-catenin signaling modulates anti-inflammatory responses in response to bacterial infection and its interactions with other inflammatory signals, which warrants further study for the development of specific interventions for the treatment of inflammatory diseases. Further clinical trials from different disease settings are required.

Anti-Apoptotic and Anti-Inflammatory Properties of Grapefruit IntegroPectin on Human Microglial HMC3 Cell Line

In this study, we investigated the beneficial effects of grapefruit IntegroPectin, derived from industrial waste grapefruit peels via hydrodynamic cavitation, on microglia cells exposed to oxidative stress conditions. Grapefruit IntegroPectin fully counteracted cell death and the apoptotic process induced by cell exposure to tert-butyl hydroperoxide (TBH), a powerful hydroperoxide. The protective effects of the grapefruit IntegroPectin were accompanied with a decrease in the amount of ROS, and were strictly dependent on the activation of the phosphoinositide 3-kinase (PI3K)/Akt cascade. Finally, IntegroPectin treatment inhibited the neuroinflammatory response and the basal microglia activation by down-regulating the PI3K- nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB)- inducible nitric oxide synthase (iNOS) cascade. These data strongly support further investigations aimed at exploring IntegroPectin's therapeutic role in in vivo models of neurodegenerative disorders, characterized by a combination of chronic neurodegeneration, oxidative stress and neuroinflammation.

Antioxidant Efficacy of Hwangryunhaedok-tang through Nrf2 and AMPK Signaling Pathway against Neurological Disorders In Vivo and In Vitro

Alzheimer's disease (AD) is a representative cause of dementia and is caused by neuronal loss, leading to the accumulation of aberrant neuritic plaques and the formation of neurofibrillary tangles. Oxidative stress is involved in the impaired clearance of amyloid beta (Aβ), and Aβ-induced oxidative stress causes AD by inducing the formation of neurofibrillary tangles. Hwangryunhaedok-tang (HHT, Kracie K-09®), a traditional herbal medicine prescription, has shown therapeutic effects on various diseases. However, the studies of HHT as a potential treatment for AD are insufficient. Therefore, our study identified the neurological effects and mechanisms of HHT and its key bioactive compounds against Alzheimer's disease in vivo and in vitro. In a 5xFAD mouse model, our study confirmed that HHT attenuated cognitive impairments in the Morris water maze (MWM) test and passive avoidance (PA) test. In addition, the prevention of neuron impairment, reduction in the protein levels of Aβ, and inhibition of cell apoptosis were confirmed with brain tissue staining. In HT-22 cells, HHT attenuates tBHP-induced cytotoxicity, ROS generation, and mitochondrial dysfunction. It was verified that HHT exerts a neuroprotective effect by activating signaling pathways interacting with Nrf2, such as MAPK/ERK, PI3K/Akt, and LKB1/AMPK. Among the components, baicalein, a bioavailable compound of HHT, exhibited neuroprotective properties and activated the Akt, AMPK, and Nrf2/HO-1 pathways. Our findings indicate a mechanism for HHT and its major bioavailable compounds to treat and prevent AD and suggest its potential.

Protective mechanism of Paeonol on central nervous system

Cerebrovascular diseases involve neuronal damage, resulting in degenerative neuropathy and posing a serious threat to human health. The discovery of effective drug components from natural plants and the study of their mechanism are a research idea different from chemical synthetic medicines. Paeonol is the main active component of traditional Chinese medicine Paeonia lactiflora Pall. It widely exists in many medicinal plants and has pharmacological effects such as anti-atherosclerosis, antiplatelet aggregation, anti-oxidation, and anti-inflammatory, which keeps generally used in the treatment of cardiovascular and cerebrovascular diseases. Based on the therapeutic effects of Paeonol for cardiovascular and cerebrovascular diseases, this article reviewed the pharmacological effects of Paeonol in Alzheimer's disease, Parkinson's disease, stroke, epilepsy, diabetes encephalopathy, and other neurological diseases, providing a reference for the research of the mechanism of Paeonol in central nervous system diseases.

MKP-1 regulates the inflammatory activation of microglia against Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases leading to dementia in elderly people. Microglia-mediated neuroinflammation plays an important role in AD pathogenesis, so modulation of neuroinflammation has emerged as an essential therapeutic method to improve AD. The current study aims to investigate whether MKP-1 can regulate microglia phenotype and inflammatory factor release in AD and explore its possible mechanisms.

METHODS

Amyloid precursor protein/PS1 double transgenic mice and wild-type mice were selected to study the locations of microglia and amyloid-β (Aβ) plaques in different regions of mice brains. Changes in MKP-1 of microglia were detected using AD model mice and AD model cells. Changes in phenotype and the release of inflammatory factors within immortalized BV2 murine microglia were investigated by regulating the expression of MKP-1.

RESULTS

The distribution of microglia and Aβ plaques in the AD brain was region-specific. MKP-1 expression was downregulated in AD mice, and in vitro, with increasing Aβ concentrations, MKP-1 expression was reduced. MKP-1 over-expression increased M2 microglia but decreased M1 microglia accompanied by changes in inflammatory factors and inhibition of MKP-1 yielded the opposite result.

CONCLUSION

MKP-1 regulated microglia phenotype and inflammatory factor release in AD through modulation of the p38 signaling pathway.

Amelioration of Astrocyte-Mediated Neuroinflammation by EI-16004 Confers Neuroprotection in an MPTP-induced Parkinson's Disease Model

Parkinson's disease (PD) is a neurodegenerative disorder that results in motor impairment due to dopaminergic neuronal loss. The pathology of PD is closely associated with neuroinflammation, which can be characterized by astrocyte activation. Thus, targeting the inflammatory response in astrocytes might provide a novel therapeutic approach. We conducted a luciferase assay on an in-house chemical library to identify compounds with anti-inflammatory effects capable of reducing MPP+-induced NF-κB activity in astrocytes. Among the compounds identified, EI-16004, a novel 3-benzyl-N-phenyl-1H-pyrazole-5-carboxamides, exhibited a significant anti-inflammatory effect by significantly reducing MPP+-induced astrocyte activation. Biochemical analysis and docking simulation indicated that EI-16004 inhibited the MPP+-induced phosphorylation of p65 by attenuating ERK phosphorylation, and EI-16004 reduced pro-inflammatory cytokine and chemokine levels in astrocytes. In vivo studies on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model in male C57BL/6 mice showed that EI-16004 ameliorated motor impairment and protected against dopaminergic neuronal loss, and EI-16004 effectively mitigated the MPTP-induced astrocyte activation in striatum (STR) and substantia nigra (SN). These results indicate EI-16004 is a potential neuroprotective agent for the prevention and treatment of astrocyte-mediated neuroinflammatory conditions in PD.

The underlying mechanisms of DNA methylation in high salt memory in hypertensive vascular disease

This study demonstrates the effect and DNA methylation-related mechanisms of a high-salt diet and salt memory-induced hypertension and vasculopathy. Thirty Sprague Dawley rats were randomly divided into a control (CON) group (n = 6) and a modeling group (n = 24). A 12% NaCl solution (1 mL/100 g) was intragastrically administered for 60 consecutive days for modeling. An increase in blood pressure up to 140 mmHg was considered successful modeling. Twelve of fifteen successfully modeled rats were randomly selected and divided into a High Salt Diet (HSD) group and a High Salt Memory (HSM) group (n = 6). Rats in HSD group were intragastrically administered a 12% NaCl solution, while rats in HSM group were administered a 3% NaCl solution twice a day for 30 days. At the end of the intervention, blood pressure and the serum levels of ET-1, NO, TNF-α and IL-1β were measured. RRBS-heavy sulfite sequencing technology was selected for DNA methylation analysis. The systolic blood pressure of rats in the HSD group and HSM group was significantly higher than that in the CON group. Compared with those in the CON group, the serum levels of ET-1 in the HSM group and the serum levels of NO in the HSD group and HSM group were significantly increased. The methylation level of the CON group was lower than that of the HSD group and the HSM group, and there was no significant difference between the HSD group and the HSM group. The methylation level of Myoz3 was downregulated in the HSD group and HSM group. The methylation level of Fgd3 were upregulated in HSD group and downregulated in the HSM group. The methylation levels of AC095693.1, Adamts3, PDGFA and PDGFRα were downregulated in the HSD group and upregulated in the HSM group. According to the GO database, the differentially methylated genes were significantly enriched in the coordination of cell function, genetic development, and RNA transcription. There were three main metabolic pathways that were enriched in the differentially expressed genes between the groups: the PI3K-Akt signaling pathway, MAPK signaling pathway, and Hippo signaling pathway. Excessive salt intake may cause hypertension and vascular damage, and this damage may continue after the reduction of salt intake. Therefore, salt memory phenomenon exists, and this memory effect may be correlated with the levels of DNA methylation.

METTL3-deficiency Suppresses Neural Apoptosis to Induce Protective Effects in Cerebral I/R Injury via Inhibiting RNA m6A Modifications: A Pre-clinical and Pilot Study

N6-Methyladenosine (m6A) RNA methylation involves in regulating the initiation, progression and aggravation of cerebral ischemia-reperfusion (I/R) injury, however, the detailed functions and mechanisms by which m6A drives cerebral I/R injury are not fully understood. This study found that methyltransferase-like 3 (METTL3) m6A-dependently regulated cerebral I/R injury trough regulating a novel LncRNA ABHD11-AS1/miR-1301-3p/HIF1AN/HIF-1α axis. Specifically, the middle cerebral artery occlusion (MCAO)/reperfusion mice models and glucose deprivation (OGD)/reoxygenation (RX) astrocyte cell models were respectively established, and we verified that METTL3, ABHD11-AS1 and HIF1AN were upregulated, whereas miR-1301-3p and HIF-1α were downregulated in both MCAO/reperfusion mice tissues and OGD/RX astrocytes. Mechanical experiments confirmed that METTL3 m6A dependently increased stability and expression levels of ABHD11-AS1, and elevated ABHD11-AS1 sponged miR-1301-3p to upregulate HIF1AN, resulting in the downregulation of HIF-1α. Moreover, silencing of METTL3 rescued MCAO/reperfusion and OGD/RX-induced oxidative stress-associated cell apoptosis and cell cycle arrest in both mice brain tissues in vivo and the mouse primary astrocytes in vitro, which were abrogated by overexpressing ABHD11-AS1 and downregulating miR-1301-3p. Taken together, our study firstly reported a novel METTL3/m6A/ ABHD11-AS1/miR-1301-3p/HIF1AN/HIF-1α signaling cascade in regulating the progression of cerebral I/R injury, and future work will focus on investigating whether the above genes can be used as biomarkers for the treatment of cerebral I/R injury by performing clinical studies.

Neuroprotective role of FOXA1 in Parkinson's disease: Involvements of NF1 transcription activation and MAPK signaling pathway inhibition

Forkhead box A1 (FOXA1), a member of the forkhead family of transcription factors, plays a crucial role in the development of various organ systems and exhibits neuroprotective properties. This study aims to investigate the effect of FOXA1 on Parkinson's disease (PD) and unravel the underlying mechanism. Transcriptome analysis of PD was conducted using three GEO datasets to identify aberrantly expressed genes. A mouse model of PD was generated by injecting neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP), resulting in reduced FOXA1 expression. FOXA1 decline was also observed in 1-methyl-4-phenylpyridinium-treated SH-SY5Y cells. Artificial upregulation of FOXA1 improved motor abilities of mice according to rotarod and pole tests, and it mitigated tissue damage, cell loss, and neuronal damage in the mouse substantia nigra or in vitro. FOXA1 was found to bind to the neurofibromin 1 (NF1) promoter, thereby inducing its transcription and inactivating the mitogen-activated protein kinase (MAPK) signaling pathway. Further experimentation revealed that silencing NF1 in mice or SH-SY5Y cells counteracted the neuroprotective effects of FOXA1. In conclusion, this research suggests that FOXA1 activates NF1 transcription and inactivates the MAPK signaling pathway, ultimately ameliorating neuronal damage and motor disability in PD. The findings may offer novel ideas in the field of PD management.

Dopamine depletion alters neuroplasticity-related signaling in the rat hippocampus

Dopamine (DA) plays a significant role in regulating hippocampal function, particularly in modulating synaptic plasticity. Despite this, a comprehensive understanding of the molecular mechanisms involved in neuroplasticity-related signaling influenced by DA remains incomplete. This study aimed to elucidate the changes in the expression of key molecules related to hippocampal neuroplasticity following DA depletion in rats. To induce DA depletion, unilateral striatal infusions of 6-hydroxydopamine (6-OHDA) were administered to adult Sprague-Dawley rats. The subsequent loss of nigrostriatal DAergic signaling in these 6-OHDA-lesioned rats was confirmed using an apomorphine-induced rotation test at 4 weeks post-infusion and by assessing the expression levels of tyrosine hydroxylase (TH) through immunohistochemistry and western blotting at 7 weeks post-infusion. A decrease in DAergic signaling, evidenced by reduced TH-positive immunoreactivity, was also noted in the ipsilateral hippocampus of the lesioned rats. Interestingly, 6-OHDA infusion led to increased phosphorylation of pivotal hippocampal plasticity-related proteins, including extracellular signal-regulated kinase (ERK), protein kinase B (Akt), glycogen synthase kinase 3β (GSK3β), and cAMP response element-binding protein (CREB), in the ipsilateral hippocampus 7 weeks following the infusion. To extend these findings, in vitro experiments were conducted on primary hippocampal neurons exposed to DA and/or the active D1/D2 DA receptor antagonist, flupentixol (Flux). DA inhibited the constitutive phosphorylation of ERK, Akt, GSK3, and CREB, while Flux restored these phosphorylation levels. Taken together, these findings indicate that DA depletion triggers an increase in plasticity-related signaling in the hippocampus, suggesting a possible compensatory mechanism that promotes activity-independent neuroplasticity following DA depletion.

Exploring the Connectivity of Neurodegenerative Diseases: Microglia as the Center

Degenerative diseases affect people's life and health and cause a severe social burden. Relevant mechanisms of microglia have been studied, aiming to control and reduce degenerative disease occurrence effectively. This review discussed the specific mechanisms underlying microglia in neurodegenerative diseases, age-related hearing loss, Alzheimer's disease, Parkinson's disease, and peripheral nervous system (PNS) degenerative diseases. It also reviewed the studies of microglia inhibitors (PLX3397/PLX5622) and activators (lipopolysaccharide), and suggested that reducing microglia can effectively curb the genesis and progression of degenerative diseases. Finally, microglial cells' anti-inflammatory and pro-inflammatory dual role was considered the critical communication point in central and peripheral degenerative diseases. Although it is difficult to describe the complex morphological structure of microglia in a unified manner, this does not prevent them from being a target for future treatment of neurodegenerative diseases.

Targeting protein kinases for the treatment of Alzheimer's disease: Recent progress and future perspectives

Alzheimer's disease (AD) is a serious neurodegenerative disease characterized by memory impairment, mental retardation, impaired motor balance, loss of self-care and even death. Among the complex and diverse pathological changes in AD, protein kinases are deeply involved in abnormal phosphorylation of Tau proteins to form intracellular neuronal fiber tangles, neuronal loss, extracellular β-amyloid (Aβ) deposits to form amyloid plaques, and synaptic disturbances. As a disease of the elderly, the growing geriatric population is directly driving the market demand for AD therapeutics, and protein kinases are potential targets for the future fight against AD. This perspective provides an in-depth look at the role of the major protein kinases (GSK-3β, CDK5, p38 MAPK, ERK1/2, and JNK3) in the pathogenesis of AD. At the same time, the development of different protein kinase inhibitors and the current state of clinical advancement are also outlined.

Advances of phytotherapy in ischemic stroke targeting PI3K/Akt signaling

The pathogenesis of ischemic stroke is complex, and PI3K/Akt signaling is considered to play a crucial role in it. The PI3K/Akt pathway regulates inflammation, oxidative stress, apoptosis, autophagy, and vascular endothelial homeostasis after cerebral ischemia; therefore, drug research targeting the PI3K/Akt pathway has become the focus of scientists. In this review, we analyzed the research reports of antiischemic stroke drugs targeting the PI3K/Akt pathway in the past two decades. Because of the rich sources of natural products, increasing studies have explored the value of natural compounds, including Flavonoids, Quinones, Alkaloids, Phenylpropanoids, Phenols, Saponins, and Terpenoids, in alleviating neurological impairment and achieved satisfactory results. Herbal extracts and medicinal formulas have been applied in the treatment of ischemic stroke for thousands of years in East Asian countries. These precious clinical experiences provide a new avenue for research of antiischemic stroke drugs. Finally, we summarize and discuss the characteristics and shortcomings of the current research and put forward prospects for further in-depth exploration.

Altered expression of inflammation-associated molecules in striatum: an implication for sensitivity to heavy ion radiations

Background and objective

Heavy ion radiation is one of the major hazards astronauts face during space expeditions, adversely affecting the central nervous system. Radiation causes severe damage to sensitive brain regions, especially the striatum, resulting in cognitive impairment and other physiological issues in astronauts. However, the intensity of brain damage and associated underlying molecular pathological mechanisms mediated by heavy ion radiation are still unknown. The present study is aimed to identify the damaging effect of heavy ion radiation on the striatum and associated underlying pathological mechanisms.

Materials and methods

Two parallel cohorts of rats were exposed to radiation in multiple doses and times. Cohort I was exposed to 15 Gy of 12C6+ ions radiation, whereas cohort II was exposed to 3.4 Gy and 8 Gy with 56Fe26+ ions irradiation. Physiological and behavioural tests were performed, followed by 18F-FDG-PET scans, transcriptomics analysis of the striatum, and in-vitro studies to verify the interconnection between immune cells and neurons.

Results

Both cohorts revealed more persistent striatum dysfunction than other brain regions under heavy ion radiation at multiple doses and time, exposed by physiological, behavioural, and 18F-FDG-PET scans. Transcriptomic analysis revealed that striatum dysfunction is linked with an abnormal immune system. In vitro studies demonstrated that radiation mediated diversified effects on different immune cells and sustained monocyte viability but inhibited its differentiation and migration, leading to chronic neuroinflammation in the striatum and might affect other associated brain regions.

Conclusion

Our findings suggest that striatum dysfunction under heavy ion radiation activates abnormal immune systems, leading to chronic neuroinflammation and neuronal injury.

scAAV9-VEGF alleviates symptoms of amyotrophic lateral sclerosis (ALS) mice through regulating aromatase

Amyotrophic lateral sclerosis (ALS) is an adult-onset, chronic, progressive, and fatal neurodegenerative disease that leads to progressive atrophy and weakness of the muscles throughout the body. Herein, we found that the intrathecal injection of adeno-associated virus (AAV)-delivered VEGF in SOD1-G93A transgenic mice, as well as ALS mice, could significantly delay disease onset and preserve motor functions and neurological functions, thus prolonging the survival of mice models. Moreover, we found that VEGF treatment could induce the elevated expression of aromatase, which is a key enzyme in estrogen synthesis, in neurons but not in astrocytes. On the other hand, the changes in the expression of oxidative stress-related factors HO-1 and GCLM and autophagy-related proteins p62 and LC3II upon the administration of VEGF revealed the involvement of oxidative stress and autophagy underlying the downstream of the VEGF-induced mitigation of ALS. In conclusion, this study proved the protective effects of VEGF in the onset and development of ALS and revealed the involvement of estrogen, oxidative stress and autophagy in the VEGF-induced alleviation of ALS. Our results highlighted the potential of VEGF as a promising therapeutic agent in the treatment of ALS.

Bile acid signalling and its role in anxiety disorders

Anxiety disorder is a prevalent neuropsychiatric disorder that afflicts 7.3%~28.0% of the world's population. Bile acids are synthesized by hepatocytes and modulate metabolism via farnesoid X receptor (FXR), G protein-coupled receptor (TGR5), etc. These effects are not limited to the gastrointestinal tract but also extend to tissues and organs such as the brain, where they regulate emotional centers and nerves. A rise in serum bile acid levels can promote the interaction between central FXR and TGR5 across the blood-brain barrier or activate intestinal FXR and TGR5 to release fibroblast growth factor 19 (FGF19) and glucagon-like peptide-1 (GLP-1), respectively, which in turn, transmit signals to the brain via these indirect pathways. This review aimed to summarize advancements in the metabolism of bile acids and the physiological functions of their receptors in various tissues, with a specific focus on their regulatory roles in brain function. The contribution of bile acids to anxiety via sending signals to the brain via direct or indirect pathways was also discussed. Different bile acid ligands trigger distinct bile acid signaling cascades, producing diverse downstream effects, and these pathways may be involved in anxiety regulation. Future investigations from the perspective of bile acids are anticipated to lead to novel mechanistic insights and potential therapeutic targets for anxiety disorders.

D-Pinitol attenuates postmenopausal symptoms in ovariectomized mice

AIMS

Menopause is a natural process in women that can lead to post-menopausal syndrome with symptoms such as hot flushes, weight gain, anxiety, cognitive decline, and depression. Hormonal replacement therapy is commonly prescribed. However, it has serious adverse effects. Herbal medicinal products and isoflavones are used as alternatives. D-Pinitol found in Pinaceae and Fabaceae families has anti-inflammatory and antioxidant effects. However, it has not received as much attention as isoflavones. In this study, we investigated whether D-pinitol could alleviate post-menopausal symptoms using an ovariectomized (OVX) mouse model.

MAIN METHODS

Female ICR mice were divided into six groups: sham (vehicle), OVX (vehicle), OVX + D-pinitol (10, 30, 100 mg/kg, p.o.), and OVX + estradiol (0.5 mg/kg, s.c.). Treatment with vehicle, D-pinitol, and estradiol began at seven weeks post ovariectomy. We employed several behavioral tests, hot-flush test, and Western blot analysis.

KEY FINDINGS

We found that D-pinitol treatment (30, 100 mg/kg, p.o.) reversed cognitive dysfunction in OVX mice (novel object recognition and Y-maze test). Additionally, D-pinitol alleviated anxiety-like behaviors (elevated plus-maze) and reversed depressive-like behaviors (splash test, tail suspension test). It also normalized increased basal tail skin temperature in OVX mice. Moreover, D-pinitol administration reversed decreased expression of ERβ and synaptophysin and phosphorylation of ERK and PI3K-Akt-GSK-3β induced by OVX in the hippocampus and prefrontal cortex.

SIGNIFICANCE

These findings indicate that D-pinitol might be a promising candidate for treating post-menopausal symptoms by increasing ERβ and synaptophysin expression levels and activation of ERK or PI3K-Akt-GSK-3β signaling pathway, at least in part.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Polyphenols in edible herbal medicine: targeting gut-brain interactions in depression-associated neuroinflammation

Supplementing with edible herbal medicine is an important strategy because of its role in nutrition. Many polyphenols, which are universal components in edible herbal medicines, have low bioavailability. Therefore, gut microbiota is a key determinant of polyphenol bioactivity. Polyphenols can alter the abundance of flora associated with neuroinflammation by reversing intestinal microbiota dysbiosis. Intestinal flora-mediated chemical modification of polyphenols can result in their conversion into active secondary metabolites. The current review summarizes the main edible medicines used in anti-depression and details the interactions between polyphenols and gut microbiota; in addition, it provides insights into the mechanisms underlying the possible suppression of neuroinflammation associated with depression, by polyphenols in edible herbal medicine. A better understanding of polyphenols with bioactivities that are crucial in edible herbal medicine may facilitate their use in the prevention and treatment of neuroinflammation associated with depression.

An Overview of Recent Advances in the Neuroprotective Potentials of Fisetin against Diverse Insults in Neurological Diseases and the Underlying Signaling Pathways

The nervous system plays a leading role in the regulation of physiological functions and activities in the body. However, a variety of diseases related to the nervous system have a serious impact on human health. It is increasingly clear that neurological diseases are multifactorial pathological processes involving multiple cellular systems, and the onset of these diseases usually involves a diverse array of molecular mechanisms. Unfortunately, no effective therapy exists to slow down the progression or prevent the development of diseases only through the regulation of a single factor. To this end, it is pivotal to seek an ideal therapeutic approach for challenging the complicated pathological process to achieve effective treatment. In recent years, fisetin, a kind of flavonoid widely existing in fruits, vegetables and other plants, has shown numerous interesting biological activities with clinical potentials including anti-inflammatory, antioxidant and neurotrophic effects. In addition, fisetin has been reported to have diverse pharmacological properties and neuroprotective potentials against various neurological diseases. The neuroprotective effects were ascribed to its unique biological properties and multiple clinical pharmacological activities associated with the treatment of different neurological disorders. In this review, we summarize recent research progress regarding the neuroprotective potential of fisetin and the underlying signaling pathways of the treatment of several neurological diseases.

Protective effect of MitoTEMPO against cardiac dysfunction caused by ischemia-reperfusion: MCAO stroke model study

PURPOSE

Neurological impairments are the leading cause of post-stroke mortality, while stroke-related cardiovascular diseases rank second in significance. This study investigates the potential protective effects of MitoTEMPO (2,2,6,6-tetramethyl-4-[[2-(triphenylphosphonio) acetyl] amino]-1-piperidinyloxy, monochloride, monohydrate), a mitochondria-specific antioxidant, against cardiac and neurological complications following stroke. The objective is to assess whether MitoTEMPO can be utilized as a protective agent for individuals with a high risk of stroke.

MATERIALS AND METHODS

Seventeen-week-old male Wistar Albino rats were randomly assigned to three groups: SHAM, ischemia-reperfusion and MitoTEMPO + ischemia-reperfusion (MitoTEMPO injection 0.7 mg/kg/day for 14 days). The SHAM group underwent a sham operation, while the ischemia-reperfusion group underwent 1-h middle cerebral artery occlusion followed by three days of reperfusion. Afterwards, noninvasive thoracic electrical bioimpedance and electrocardiography measurements were taken, and sample collection was performed for histological and biochemical examinations.

RESULTS

Our thoracic electrical bioimpedance and electrocardiography findings demonstrated that MitoTEMPO exhibited a protective effect on most parameters affected by ischemia-reperfusion compared to the SHAM group. Furthermore, our biochemical and histological data revealed a significant protective effect of MitoTEMPO against oxidative damage.

CONCLUSIONS

The findings suggest that both ischemia-reperfusion-induced cardiovascular abnormalities and the protective effect of MitoTEMPO may involve G-protein coupled receptor-mediated signaling mechanisms. This study was conducted with limitations including a single gender, a uniform age group, a specific stroke model limited to middle cerebral artery, and pre-scheduled only one ischemia-reperfusion period. In future studies, addressing these limitations may enable the implementation of preventive measures for individuals at high risk of stroke.

Microglia mediated neuroinflammation in neurodegenerative diseases: A review on the cell signaling pathways involved in microglial activation

Microglia, the immune sentinels of the central nervous system (CNS), have emerged to be the central players in many neurological and neurodegenerative diseases. Recent studies on large genome databases and omics studies in fact provide support to the idea that microglial cells could be the drivers of these diseases. Microglial cells have the capacity to undergo morphological and phenotypic transformations depending on its microenvironment. From the homeostatic ramified state, they can shift their phenotypes between the two extremes, known as the proinflammatory M1 and anti-inflammatory M2 phenotype, with intermediate transitional states, characterized by different transcriptional signature and release of inflammatory mediators. The temporal regulation of the release of the inflammatory factors are critical for damage control and steering the microglia back towards homeostatic conditions. A dysregulation in these can lead to excessive tissue damage and neuronal death. Therefore, targeting the cell signaling pathways that are the underpinnings of microglial modulations are considered to be an important avenue for treatment of various neurodegenerative diseases. In this review we have discussed various signaling pathways that trigger microglial activation from its ramified state and highlight the mechanisms of microglia-mediated neuroinflammation that are associated with various neurodegenerative diseases. Most of the cellular factors that drive microglia towards a proinflammatory phenotype are components of the immune system signaling pathways and cell proliferation, along with certain ion channels. The anti-inflammatory phenotype is mainly elicited by purinoceptors, metabolic receptors and other receptors that primarily suppress the production proinflammatory mediators.

Identifying the potential genes in alpha synuclein driving ferroptosis of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease with aggregation of α-synuclein (α-syn) in substantia nigra (SN). The association between the α-syn and ferroptosis in PD remains unclear. GSE49036 was obtained from the Gene Expression Omnibus (GEO) database and intersected with ferroptosis genes. Bioinformatics analysis was used to identify the potential differentially expressed genes (DEGs) included the development of Gene set enrichment analysis (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction (PPI) network. We screened 8 key genes were modulated and crosslinked by 238 miRNAs. Additionally, 5 hub genes were predicted and 38 lncRNAs targeting 3 key miRNAs were revealed. Finally, 3 hub genes (PIK3CA, BRD4, ATM) and the key lncRNA (NEAT1) were verified in neurotoxic PD models. The in vitro experiments showed that PIK3CA and ATM were significantly upregulated or the BRD4 was downregulated in the rotenone treatment and they could be rescued by the specific ferroptosis inhibitor, liproxstatin-1. The expression of the key lncRNA NEAT1 were consistent with the hub genes in same models. This study identified the proposed NEAT1-PIK3CA/ATM ceRNA network may be a specific biomarker in α-syn driving ferroptosis as well as to predict clinical outcomes and therapeutic targets in PD patients.

Progression of the PI3K/Akt signaling pathway in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterized by a slow progression and caused by the inhalation of harmful particulate matter. Cigarette smoke and air pollutants are the primary contributing factors. Currently, the pathogenesis of COPD remains incompletely understood. The PI3K/Akt signaling pathway has recently emerged as a critical regulator of inflammation and oxidative stress response in COPD, playing a pivotal role in the disease's progression and treatment. This paper reviews the association between the PI3K/Akt pathway and COPD, examines effective PI3K/Akt inhibitors and novel anti-COPD agents, aiming to identify new therapeutic targets for clinical intervention in this disease.

GPR34 Knockdown Relieves Cognitive Deficits and Suppresses Neuroinflammation in Alzheimer's Disease via the ERK/NF-κB Signal

Alzheimer's disease (AD) is a serious neurodegenerative disease characterized by amyloid-β (Aβ) aggregation and neuroinflammation. G-protein-coupled receptor 34 (Gpr34) was found highly expressed in the hippocampus of APP/PS1 mice. However, its role in AD remains unclear. Herein, the role of Gpr34 as well as its molecular mechanism was explored. Data in GSE85162 were analyzed and the differently expressed genes in the hippocampus tissues of APP/PS1 mouse model of AD were subjected to GO, KEGG and GSEA enrichment analyses. APP/PS1 mice were used as an animal model of AD and the cognitive impairment was evaluated by a water maze test. The level of Gpr34 in hippocampus and BV-2 cells as well as the activation of ERK/NF-κB signal was determined by quantitative real-time PCR, western blot or immunofluorescence. Our results showed that, in BV-2 cells exposed to Aβ1-42, Gpr34 knockdown decreased the levels of TNF-α, IL-1β, IL-6 and iNOS and suppressed the activation of ERK/NF-κB signal. Moreover, the Gpr34-overexpression-induced activation of ERK/NF-κB signal and up-regulated levels of TNF-α, IL-1β, IL-6 and iNOS were abolished by FR180204, an ERK inhibitor. On the other hand, the in vivo study showed that Gpr34 knockdown ameliorated the cognitive impairment in APP/PS1 mice, decreased the levels of TNF-α, IL-1β and IL-6, the activation of microglia and ERK/NF-κB signal. In conclusion, Gpr34 knockdown relieved cognitive deficits in APP/PS1 mice and suppressed neuroinflammation and microglial activation, maybe via the ERK/NF-κB signal. It is indicated that the high level of Grp34 in hippocampus may contribute to the pathogenesis of AD.

Involvement of brain-derived neurotrophic factor signaling in the pathogenesis of stress-related brain diseases

Neurotrophins including brain-derived neurotrophic factor, BDNF, have critical roles in neuronal differentiation, cell survival, and synaptic function in the peripheral and central nervous system. It is well known that a variety of intracellular signaling stimulated by TrkB, a high-affinity receptor for BDNF, is involved in the physiological and pathological neuronal aspects via affecting cell viability, synaptic function, neurogenesis, and cognitive function. As expected, an alteration of the BDNF/TrkB system is suspected to be one of the molecular mechanisms underlying cognitive decline in cognitive diseases and mental disorders. Recent evidence has also highlighted a possible link between the alteration of TrkB signaling and chronic stress. Furthermore, it has been demonstrated that downregulation of the BDNF/TrkB system and chronic stress have a role in the pathogenesis of Alzheimer's disease (AD) and mental disorders. In this review, we introduce current evidence showing a close relationship between the BDNF/TrkB system and the development of cognition impairment in stress-related disorders, and the possible contribution of the upregulation of the BDNF/TrkB system in a therapeutic approach against these brain diseases.

Embelin targets PI3K/AKT and MAPK in age-related ulcerative colitis: an integrated approach of microarray analysis, network pharmacology, molecular docking, and molecular dynamics

Vaibhdang, an Ayurvedic treatment for Crohn's and UC, has been used for centuries. The main component of Vaibhdang is embelin derived from Embelia ribes. However, the pharmacological and molecular mechanisms of embelin in UC remain unclear. This study investigated the molecular targets and mechanisms of action of embelin in UC using microarray analysis, network pharmacology, molecular docking, and molecular dynamics simulations. Embelin targets were obtained by Swiss Target, TargetNet, STITCH, ChEMBL, and TCMSP. Ulcerative colitis targets were mapped using DisGenNET, Genecards, TCMSP, Therapeutic targets, and GEO databases (GSE87466). Co-targets between ulcerative colitis and embelin were identified, and a PPI network was constructed using the STRING database. To identify the core targets, we used Cytoscape to analyze the topology of the PPI network. There were 545 effective Embelin targets and 5171 effective ulcerative colitis targets, including 1470 DEG targets. ShinyGo and AutoDock were used to analyze GO and KEGG enrichment pathways and docking studies, respectively. Venn diagram analysis revealed 327 core targets of embelin in UC. An enrichment study showed that embelin is involved in PI3K-AKT, MAPK, RAS, and chemokine signalling. The top ten core targets docked with embelin and AKT1, MAPK1, and SRC complexes were utilized as representations and simulated using GROMACS for 100 ns. A comparison of native proteins and their complex interactions with embelin revealed that embelin might act on various PI3K/AKT and MAPK targets to treat ulcerative colitis. This study provides insights into the molecular targets and mechanisms of action of embelin against ulcerative colitis.Communicated by Ramaswamy H. Sarma.

Neuroprotective Effects of Tinospora cordifolia via Reducing the Oxidative Stress and Mitochondrial Dysfunction against Rotenone-Induced PD Mice

Oxidative stress and mitochondrial dysfunction are leading mechanisms that play a crucial role in the progression of Parkinson's disease (PD). Tinospora cordifolia shows a wide range of biological activities including immunomodulatory, antimicrobial, antioxidant, and anti-inflammatory properties. This study explored the neuroprotective activities of T. cordifolia ethanolic extract (TCE) against Rotenone (ROT)-intoxicated Parkinsonian mice. Four experimental groups of mice were formed: control, ROT (2 mg/kg body wt, subcutaneously), TCE (200 mg/kg body wt, oral) + ROT, and TCE only. Mice were pretreated with TCE for a week and then simultaneously injected with ROT for 35 days. Following ROT-intoxication, motor activities, antioxidative potential, and mitochondrial dysfunction were analyzed. Decrease in the activity of the mitochondrial electron transport chain (mETC) complex, loss of mitochondrial membrane potential (Ψm), increase in Bax/Bcl-2 (B-cell lymphoma 2) ratio, and caspase-3 expression are observed in the ROT-intoxicated mice group. Our results further showed ROT-induced reactive oxygen species (ROS)-mediated alpha-synuclein (α-syn) accumulation and mitochondrial dysfunction. However, pre- and cotreatment with TCE along with ROT-intoxication significantly reduced α-syn aggregation and improved mitochondrial functioning in cells by altering mitochondrial potential and increasing mETC activity. TCE also decreases the Bax/Bcl-2 ratio and also the expression of caspase-3, thus reducing apoptosis of the cell. Altogether, TCE is effective in protecting neurons from rotenone-induced cytotoxicity in the Parkinsonian mouse model by modulating oxidative stress, ultimately reducing mitochondrial dysfunction and cell death.

Keratin8 Deficiency Aggravates Retinal Ganglion Cell Damage Under Acute Ocular Hypertension

Purpose

Keratin 8/18 (KRT8/18), paired members of the intermediate filament family, have shown vital functions in regulating physiological activities more than supporting the mechanic strength for cells and organelles. However, the KRT8/18 presence in retinal ganglion cells (RGCs) and functions on neuroprotection in a mouse model of acute ocular hypertension (AOH) are unknown and worthy of exploration.

Methods

We identified the existence of KRT8/18 in normal human and mouse retinas and primary RGCs. KRT8/18 levels were detected after AOH modeling. The adeno-associated virus (AAV) system was intravitreally used for selective KRT8 knockdown in RGCs. The histological changes, the loss and dysfunction of RGCs, and the gliosis in retinas were detected. The markers of cell apoptosis and MAPK pathways were investigated.

Results

KRT8/18 existed in all retinal layers and was highly expressed in RGCs, and they increased after AOH induction. The KRT8 knockdown in RGCs caused no histopathological changes and RGC loss in retinas without AOH modeling. However, after the KRT8 deficiency, AOH significantly promoted the loss of whole retina and inner retina thickness, the reduction, apoptosis, and dysfunction of RGCs, and the glial activation. Besides, downregulated Bcl-2 and upregulated cleaved-Caspase 3 were found in the AOH retinas with KRT8 knockdown, which may be caused by the increased phosphorylation level of MAPK pathways (JNK, p38, and ERK).

Conclusions

The KRT8 deficiency promoted RGC apoptosis and neurodegeneration by abnormal activation of MAPK pathways in AOH retinas. Targeting KRT8 may serve as a novel treatment for saving RCGs from glaucomatous injuries.

Neuroprotective potential of trimetazidine against tramadol-induced neurotoxicity: role of PI3K/Akt/mTOR signaling pathways

Tramadol (TRA) causes neurotoxicity whereas trimetazidine (TMZ) is neuroprotective. The potential involvement of the PI3K/Akt/mTOR signaling pathway in the neuroprotection of TMZ against TRA-induced neurotoxicity was evaluated. Seventy male Wistar rats were divided into groups. Groups 1 and 2 received saline or TRA (50 mg/kg). Groups 3, 4, and 5 received TRA (50 mg/kg) and TMZ (40, 80, or 160 mg/kg) for 14 days. Group 6 received TMZ (160 mg/kg). Hippocampal neurodegenerative, mitochondrial quadruple complex enzymes, phosphatidylinositol-3-kinases (PI3Ks)/protein kinase B levels, oxidative stress, inflammatory, apoptosis, autophagy, and histopathology were evaluated. TMZ decreased anxiety and depressive-like behavior induced by TRA. TMZ in tramadol-treated animals inhibited lipid peroxidation, GSSG, TNF-α, and IL-1β while increasing GSH, SOD, GPx, GR, and mitochondrial quadruple complex enzymes in the hippocampus. TRA inhibited Glial fibrillary acidic protein expression and increased pyruvate dehydrogenase levels. TMZ reduced these changes. TRA decreased the level of JNK and increased Beclin-1 and Bax. TMZ decreased phosphorylated Bcl-2 while increasing the unphosphorylated form in tramadol-treated rats. TMZ activated phosphorylated PI3Ks, Akt, and mTOR proteins. TMZ inhibited tramadol-induced neurotoxicity by modulating the PI3K/Akt/mTOR signaling pathways and its downstream inflammatory, apoptosis, and autophagy-related cascades.

Quantitative proteomics and phosphoproteomics of PP2A-PPP2R5D variants reveal deregulation of RPS6 phosphorylation via converging signaling cascades

Genetic germline variants of PPP2R5D (encoding: phosphoprotein phosphatase 2 regulatory protein 5D) result in PPP2R5D-related disorder (Jordan's Syndrome), which is characterized by intellectual disability, hypotonia, seizures, macrocephaly, autism spectrum disorder, and delayed motor skill development. The disorder originates from de novo single nucleotide mutations, generating missense variants that act in a dominant manner. Pathogenic mutations altering 13 different amino acids have been identified, with the E198K variant accounting for ∼40% of reported cases. However, the generation of a heterozygous E198K variant cell line to study the molecular effects of the pathogenic mutation has been challenging. Here, we use CRISPR-PRIME genomic editing to introduce a transition (c.592G>A) in a single PPP2R5D allele in HEK293 cells, generating E198K-heterozygous lines to complement existing E420K variant lines. We generate global protein and phosphorylation profiles of WT, E198K, and E420K cell lines and find unique and shared changes between variants and WT cells in kinase- and phosphatase-controlled signaling cascades. We observed ribosomal protein S6 (RPS6) hyperphosphorylation as a shared signaling alteration, indicative of increased ribosomal protein S6-kinase activity. Treatment with rapamycin or an RPS6-kinase inhibitor (LY2584702) suppressed RPS6 phosphorylation in both, suggesting upstream activation of mTORC1/p70S6K. Intriguingly, our data suggests ERK-dependent activation of mTORC1 in both E198K and E420K variant cells, with additional AKT-mediated mTORC1 activation in the E420K variant. Thus, although upstream activation of mTORC1 differs between PPP2R5D-related disorder genotypes, inhibition of mTORC1 or RPS6 kinases warrants further investigation as potential therapeutic strategies for patients.

Overview on the Polyphenol Avenanthramide in Oats (Avena sativa Linn.) as Regulators of PI3K Signaling in the Management of Neurodegenerative Diseases

Avenanthramides (Avns) and their derivatives, a group of polyphenolic compounds found abundantly in oats (Avena sativa Linn.), have emerged as promising candidates for neuroprotection due to their immense antioxidant, anti-inflammatory, and anti-apoptotic properties. Neurodegenerative diseases (NDDs), characterized by the progressive degeneration of neurons, present a significant global health burden with limited therapeutic options. The phosphoinositide 3-kinase (PI3K) signaling pathway plays a crucial role in cell survival, growth, and metabolism, making it an attractive target for therapeutic intervention. The dysregulation of PI3K signaling has been implicated in the pathogenesis of various NDDs including Alzheimer's and Parkinson's disease. Avns have been shown to modulate PI3K/AKT signaling, leading to increased neuronal survival, reduced oxidative stress, and improved cognitive function. This review explores the potential of Avn polyphenols as modulators of the PI3K signaling pathway, focusing on their beneficial effects against NDDs. Further, we outline the need for clinical exploration to elucidate the specific mechanisms of Avn action on the PI3K/AKT pathway and its potential interactions with other signaling cascades involved in neurodegeneration. Based on the available literature, using relevant keywords from Google Scholar, PubMed, Scopus, Science Direct, and Web of Science, our review emphasizes the potential of using Avns as a therapeutic strategy for NDDs and warrants further investigation and clinical exploration.

Dipeptide mimetic of BDNF ameliorates motor dysfunction and striatal apoptosis in 6-OHDA-induced Parkinson's rat model: Considering Akt and MAPKs signaling

Parkinson's disease (PD) is a progressive and debilitating neurodegenerative disorder associated with motor and non-motor complaints. Dysregulation of neurotrophic factors and related signaling cascades have been reported to be common events in PD which is accompanied by dopaminergic (DA) neuron demise. However, the restoration of neurotrophic factors has several limitations. Bis-(N-monosuccinyl-L-methionyl-L-serine) heptamethylenediamide (BHME) is a dipeptide mimetic of brain-derived neurotrophic factor (BDNF) with reported anti-oxidant and neuroprotective effects in several experimental models. The current study has investigated the effect of BHME on 6-hydroxydopamine (6-OHDA)-caused motor anomalies in Wistar rats. In this regard, rats were treated daily with BHME (0.1 or 1 mg/kg) 1 h after 6-OHDA-caused damage until the twelfth day. Afterwards, motor behavior and DA neuron survival were evaluated via behavioral tests and immunohistochemistry (IHC) staining, respectively. Moreover, the activity of Akt, mitogen-activated protein kinases (MAPKs) family, and Bax/Bcl-2 ratio were evaluated by Western blotting. Our results indicated that BHME prevents motor dysfunction and DA cell death following 6-OHDA injection, and this improvement was in parallel with an enhancement in Akt activity, decrement of P38 phosphorylation, along with a reduction in Bax/Bcl-2 ratio. In conclusion, our findings indicated that BHME, as a mimetic of BDNF, can be considered for further research and is a promising therapeutic agent for PD therapy.

The Expression of Epac2 and GluA3 in an Alzheimer's Disease Experimental Model and Postmortem Patient Samples

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases, characterized by amyloid beta (Aβ) and hyperphosphorylated tau accumulation in the brain. Recent studies indicated that memory retrieval, rather than memory formation, was impaired in the early stage of AD. Our previous study reported that pharmacological activation of hippocampal Epac2 promoted memory retrieval in C57BL/6J mice. A recent study suggested that pharmacological inhibition of Epac2 prevented synaptic potentiation mediated by GluA3-containing AMPARs. In this study, we aimed to investigate proteins associated with Epac2-mediated memory in hippocampal postmortem samples of AD patients and healthy controls compared with the experimental AD model J20 and wild-type mice. Epac2 and phospho-Akt were downregulated in AD patients and J20 mice, while Epac1 and phospho-ERK1/2 were not altered. GluA3 was reduced in J20 mice and tended to decrease in AD patients. PSD95 tended to decrease in AD patients and J20. Interestingly, AKAP5 was increased in AD patients but not in J20 mice, implicating its role in tau phosphorylation. Our study points to the downregulation of hippocampal expression of proteins associated with Epac2 in AD.

Exploring the active components and mechanism of modified bazhen decoction in treatment of chronic cerebral circulation insufficiency based on network pharmacology and molecular docking

Modified bazhen decoction (MBZD) is a classical Chinese medicine formula with potential efficacy in the treatment of chronic cerebral circulation insufficiency (CCCI), and its main components and potential mechanisms are still unclear. The study aimed to investigate the active ingredients and mechanism of action of MBZD in treating CCCI through network pharmacology combined with molecular docking. The chemical composition and targets of 11 Chinese herbs in MBZD were retrieved utilizing the traditional Chinese medicine systems pharmacology database and analysis platform platform, and the targets for CCCI were screened by Genecards, online mendelian inheritance in man, therapeutic target database, and comparative toxicogenomics database databases. The targets were genetically annotated with the Uniprot database. We created a compound-target network employing Cytoscape software and screened the core targets for the treatment of CCCI by CytoNCA clustering analysis; the AutoDock Vina program performed molecular docking study of crucial targets. One thousand one hundred ninety-one active compounds were obtained, 2210 corresponding targets were predicted, 4971 CCCI-related targets were obtained, and 136 intersecting genes were identified between them. The central core targets were IL6, MAPK14, signal transducer and activator of transcription 3, RELA, VEGFA, CCND1, CASP3, AR, FOS, JUN, EGFR, MAPK1, AKT1, MYC, and ESR1; gene ontology functional enrichment analysis yielded 911 gene ontology items (P < .01), while Kyoto Encyclopedia of Genes and Genomes pathway enrichment yielded 138 signal pathways (P < .01), primarily including oxidative reactions, vascular regulation, apoptosis, and PI3K-Akt signaling pathway. The molecular docking results showed that the core active component of MBZD had good binding with the main target. This research initially uncovered the mechanism of action of MBZD via multi-component-multi-target-multi-pathway for the treatment of CCCI, providing the theoretical basis for the clinical application of MBZD.

Alzheimer's Disease and Green Tea: Epigallocatechin-3-Gallate as a Modulator of Inflammation and Oxidative Stress

Alzheimer's disease (AD) is the most common cause of dementia, characterised by a marked decline of both memory and cognition, along with pathophysiological hallmarks including amyloid beta peptide (Aβ) accumulation, tau protein hyperphosphorylation, neuronal loss and inflammation in the brain. Additionally, oxidative stress caused by an imbalance between free radicals and antioxidants is considered one of the main risk factors for AD, since it can result in protein, lipid and nucleic acid damage and exacerbate Aβ and tau pathology. To date, there is a lack of successful pharmacological approaches to cure or even ameliorate the terrible impact of this disease. Due to this, dietary compounds with antioxidative and anti-inflammatory properties acquire special relevance as potential therapeutic agents. In this context, green tea, and its main bioactive compound, epigallocatechin-3-gallate (EGCG), have been targeted as a plausible option for the modulation of AD. Specifically, EGCG acts as an antioxidant by regulating inflammatory processes involved in neurodegeneration such as ferroptosis and microglia-induced cytotoxicity and by inducing signalling pathways related to neuronal survival. Furthermore, it reduces tau hyperphosphorylation and aggregation and promotes the non-amyloidogenic route of APP processing, thus preventing the formation of Aβ and its subsequent accumulation. Taken together, these results suggest that EGCG may be a suitable candidate in the search for potential therapeutic compounds for neurodegenerative disorders involving inflammation and oxidative stress, including Alzheimer's disease.

Eleven Crucial Pesticides Appear to Regulate Key Genes That Link MPTP Mechanism to Cause Parkinson's Disease through the Selective Degeneration of Dopamine Neurons

Pesticides kill neurons, but the mechanism leading to selective dopaminergic loss in Parkinson's disease (PD) is unknown. Understanding the pesticide's effect on dopaminergic neurons (DA) can help to screen and treat PD. The critical uptake of pesticides by the membrane receptors at DA is hypothesized to activate a signaling cascade and accelerate degeneration. Using MPTP as a reference, we demonstrate the mechanisms of eleven crucial pesticides through molecular docking, protein networks, regulatory pathways, and prioritization of key pesticide-regulating proteins. Participants were recruited and grouped into control and PD based on clinical characteristics as well as pesticide traces in their blood plasma. Then, qPCR was used to measure pesticide-associated gene expression in peripheral blood mononuclear cells between groups. As a result of molecular docking, all eleven pesticides and the MPTP showed high binding efficiency against 274 membrane receptor proteins of DA. Further, the protein interaction networks showed activation of multiple signaling cascades through these receptors. Subsequent analysis revealed 31 biological pathways shared by all 11pesticides and MPTP that were overrepresented by 46 crucial proteins. Among these, CTNNB1, NDUFS6, and CAV1 were prioritized to show a significant change in gene expression in pesticide-exposed PD which guides toward therapy.

Acupuncture at Back-Shu point improves insomnia by reducing inflammation and inhibiting the ERK/NF-κB signaling pathway

BACKGROUND

Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep. Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia, and long-term use is prone to drug resistance and other adverse reactions. Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.

AIM

To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.

METHODS

We first prepared a rat model of insomnia, and then carried out acupuncture for 7 consecutive days. After treatment, the sleep time and general behavior of the rats were determined. The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats. The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA. qRT-PCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway. Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1, MEK-2, ERK1/2 and NF-κB.

RESULTS

Acupuncture can prolong sleep duration, and improve mental state, activity, diet volume, learning ability and spatial memory. In addition, acupuncture increased the release of 1L-1β, 1L-6 and TNF-α in serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.

CONCLUSION

These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippo-campus.

Elevated retinal fibrosis in experimental myopia is involved in the activation of the PI3K/AKT/ERK signaling pathway

OBJECTIVE

This study aimed to investigate the regulatory role of the PI3K/AKT/ERK signaling pathway in retinal fibrosis in -6.0 diopter (D) lens-induced myopic (LIM) guinea pigs.

METHODS

Biological measurements of eye tissues were performed on guinea pigs to obtain their refraction, axial length, retinal thickness, physiological function, and fundus retinal status. In addition, Masson staining and immunohistochemical (IHC) assay were further done to explore the changes in retinal morphology after myopic induction. Meanwhile, hydroxyproline (HYP) content was measured to evaluate the degree of retinal fibrosis. Moreover, the levels of the PI3K/AKT/ERK signaling pathway and fibrosis-related molecules in retinal tissues including matrix metalloproteinase 2(MMP2), collagen type I (Collagen I), and α-smooth muscle actin (α-SMA) were detected by real-time quantitative PCR (qPCR) and Western blot.

RESULTS

The LIM guinea pigs showed a significant myopic shift in refractive error and an increase in axial length compared with those of the normal control (NC) group. Masson staining, hydroxyproline content determination, and IHC showed an increase in retinal fibrosis. After myopic induction, qPCR and western blot analyses showed that phosphatidylinositol-3-kinase catalytic subunit α (PIK3CA), protein kinase B (AKT), extracellular regulated protein kinase 1/2 (ERK1/2), MMP2, Collagen I, and α-SMA were consistently elevated in the LIM group than those in the NC group.

CONCLUSION

The PI3K/AKT/ERK signaling pathway was activated in the retinal tissues of myopic guinea pigs, which exaggerated fibrotic lesions and reduced retinal thickness, ultimately leading to retinal physiological dysfunctions in myopic guinea pigs.

Neurotrophic effects of intermittent fasting, calorie restriction and exercise: a review and annotated bibliography

In the last decades, important progress has been achieved in the understanding of the neurotrophic effects of intermittent fasting (IF), calorie restriction (CR) and exercise. Improved neuroprotection, synaptic plasticity and adult neurogenesis (NSPAN) are essential examples of these neurotrophic effects. The importance in this respect of the metabolic switch from glucose to ketone bodies as cellular fuel has been highlighted. More recently, calorie restriction mimetics (CRMs; resveratrol and other polyphenols in particular) have been investigated thoroughly in relation to NSPAN. In the narrative review sections of this manuscript, recent findings on these essential functions are synthesized and the most important molecules involved are presented. The most researched signaling pathways (PI3K, Akt, mTOR, AMPK, GSK3β, ULK, MAPK, PGC-1α, NF-κB, sirtuins, Notch, Sonic hedgehog and Wnt) and processes (e.g., anti-inflammation, autophagy, apoptosis) that support or thwart neuroprotection, synaptic plasticity and neurogenesis are then briefly presented. This provides an accessible entry point to the literature. In the annotated bibliography section of this contribution, brief summaries are provided of about 30 literature reviews relating to the neurotrophic effects of interest in relation to IF, CR, CRMs and exercise. Most of the selected reviews address these essential functions from the perspective of healthier aging (sometimes discussing epigenetic factors) and the reduction of the risk for neurodegenerative diseases (Alzheimer's disease, Huntington's disease, Parkinson's disease) and depression or the improvement of cognitive function.

Ca2+-Permeable TRPV1 Receptor Mediates Neuroprotective Effects in a Mouse Model of Alzheimer's Disease via BDNF/CREB Signaling Pathway

Transient receptor potential vanilloid 1 (TRPV1) protein is a Ca2+-permeable non-selective cation channel known for its pain modulation pathway. In a previous study, it was discovered that a triple-transgenic Alzheimer's disease (AD) mouse model (3xTg-AD+/+) has anti-AD effects. The expression of proteins in the brain-derived neurotrophic factor (BDNF)/cAMP response element binding protein (CREB) pathway in a 3xTg-AD/TRPV1 transgenic mice model was investigated to better understand the AD regulatory effect of TRPV1 deficiency. The results show that TRPV1 deficiency leads to CREB activation by increasing BDNF levels and promoting phosphorylation of tyrosine receptor kinase B (TrkB), extracellular signal-regulated kinase (ERK), protein kinase B (Akt), and CREB in the hippocampus. Additionally, TRPV1 deficiency-induced CREB activation increases the antiapoptotic factor B-cell lymphoma 2 (Bcl-2) gene, which consequently downregulates Bcl-2-associated X (Bax) expression and decreases cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP), which leads to the prevention of hippocampal apoptosis. In conclusion, TRPV1 deficiency exhibits neuroprotective effects by preventing apoptosis through the BDNF/CREB signal transduction pathway in the hippocampus of 3xTg-AD mice.