Structural Plasticity of Dopaminergic Neurons Requires the Activation of the D3R-nAChR Heteromer and the PI3K-ERK1/2/Akt-Induced Expression of c-Fos and p70S6K Signaling Pathway

Proteogenomic verifies targets underlying erythromycin alleviate neutrophil extracellular traps-induced inflammation

BACKGROUND

Neutrophil Extracellular Traps (NETs) are closely related to the progression of inflammation in Chronic Obstructive Pulmonary Disease (COPD). Erythromycin (EM) has been shown to inhibit inflammation in COPD, but its molecular mechanisms is still unclear. The aim of our study is investigate the molecular mechanisms of EM's anti-inflammatory effects in NETs-induced inflammation.

METHODS

Transcriptomics and proteomics data were obtained from U937 cells treated with NETs and EM. Differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were identified using R software. Pathway enrichment analyses, were employed to identify inflammation-related pathways. Cytoscape were utilized to construct network of hub targets regulated by EM which related with oxidative stress and inflammation. Additionally, Cytoscape and STRING were used to construct protein-protein interaction (PPI) network of key targets regulated by EM. The expression levels of key targets were further confirmed through WB and PCR experiments.

RESULTS

Both transcriptomics and proteomics indicate that EM decrease NETs -induced AKT1 expression. Enrichment analysis of DEGs and DEPs reveal multiple common pathways involved in EM's regulation inflammation, including the PI3K/AKT pathway, response to oxidative stress, IKK/NF-κB signaling and PTEN signaling pathway. Nine key targets in PI3K/AKT-related inflammatory pathways regulated by EM and ten targets of EM-regulated oxidative stress were identified. WB and PCR results confirmed that EM reversing the NETs-induced inflammation by modulating the activity of these targets. Furthermore, clinical samples and vitro experiments confirm that EM alleviates NETs-induced glucocorticoid resistance via inhibiting PI3K/AKT, thereby repressing inflammation.

CONCLUSIONS

Our study provides a comprehensive proteogenomic characterization of how EM alleviates NET-related inflammation, and identify PI3K/AKT play a critical role in the mechanism by which EM inhibits inflammation.

Comprehensive Analysis of the Gene Expression Profiles of Rat Brain Tissues under Environmental Exposure to Nicotine

<b>Background and Objective:</b> Nicotine-relevant smoking causes many serious issues of environmental pollution and complicated harm to human health. The present study aimed to evaluate the experimental effects of exposure to nicotine on the gene expression profiles of rat brain tissues with differentially expressed genes (DEGs). <b>Materials and Methods:</b> The rat gene expression profiles of environmental exposure to nicotine were initially screened and retrieved from the microarray dataset GSE59895 in the GEO database. Next, it was analyzed with an integrated bioinformatics pipeline. The DEGs were analyzed in Limma and functional enrichment analyses of GO terms and KEGG pathways were performed with clusterProfiler. The STRING online tools and Cytoscape StringApp were subsequently employed to construct the protein-protein interaction (PPI) network, whereas key modules and hub genes were finally explored and visualized. <b>Results:</b> There was total of 382 shared DEGs between different case groups in the experiment, whereas 9 common shared DEGs were found among all three groups. The significant enrichments of 28 GO terms and 3 KEGG pathways were comprehensively analyzed with corresponding functionally enriched genes. Then, 3 key modules and 10 hub genes were further identified and explored in the resulted PPI network. In the disease-related signaling pathways, eleven potential neuropathic disease-related genes may complement the treatment of neurodegenerative diseases. <b>Conclusion:</b> The study found that chronic exposure to nicotine would result in the differential expression of the disease-related genes, whereas these DEGs might increase the environmental risks of Huntington's disease, Alzheimer's disease and other multiple neurodegenerative diseases.

The Neuroanatomy of Induced Pluripotent Stem Cells: In Vitro Models of Subcortical Nuclei in Neurodegenerative Disorders

Neuromodulatory subcortical systems (NSSs) are monoaminergic and cholinergic neuronal groups that are markedly and precociously involved in the pathogenesis of many neurodegenerative disorders (NDDs), including Parkinson's and Alzheimer's diseases. In humans, although many tools have been developed to infer information on these nuclei, encompassing neuroimaging and neurophysiological methods, a detailed and specific direct evaluation of their cellular features in vivo has been difficult to obtain until recent years. The development of induced pluripotent stem cell (iPSC) models has allowed research to deeply delve into the cellular and molecular biology of NSS neurons. In fact, iPSCs can be produced easily and non-invasively from patients' fibroblasts or circulating blood monocytes, by de-differentiating those cells using specific protocols, and then be re-differentiated towards neural phenotypes, which may reproduce the specific features of the correspondent brain neurons (including NSS ones) from the same patient. In this review, we summarized findings obtained in the field of NDDs using iPSCs, with the aim to understand how reliably these might represent in vitro models of NSS. We found that most of the current literature in the field of iPSCs and NSSs in NDDs has focused on midbrain dopaminergic neurons in Parkinson's disease, providing interesting results on cellular pathophysiology and even leading to the first human autologous transplantation. Differentiation protocols for noradrenergic, cholinergic, and serotoninergic neurons have also been recently defined and published. Thus, it might be expected that in the near future, this approach could extend to other NSSs and other NDDs.

The Function and Mechanism of Laminaripentaose Prepared from Curdlan for the Amelioration of the Cognitive Dysfunctions in Obese Mice

Functional oligosaccharides induce specific alterations in gut microbiota, potentially providing physiological benefits. However, the effects of laminaripentaose (LPA) on metabolic syndrome and the mechanism underlying it have not been intensively investigated yet. This study aimed to determine the effects of LPA on obesity and obesity-induced cognition impairment in mice. C57BL/6N mice fed with a high-fat diet received an LPA treatment for 12 weeks. An antibiotic intervention was further applied to evaluate the effects of the gut microbiota on cognitive functions. LPA treatment (500 mg/kg) reduced the weight gain by 32.4%. Furthermore, LPA improved memory functions and reduced hippocampal insulin resistance and neuronal injury. LPA markedly reduced systemic low-grade inflammation and intestinal barrier injury. Moreover, LPA increased gut beneficial bacteria, and Butyricimonas and Bifidobacterium were increased by 94.0 and 422.7%, respectively, accompanied by increased fecal short-chain fatty acids. Interestingly, antibiotic cocktail treatment abrogated the beneficial effects of LPA on cognition, which further suggests that LPA may attenuate obesity-induced cognition impairment via the gut-brain axis. Our findings provide the first evidence for the potential of dietary LPA to prevent obesity and obesity-associated complications.

17-β-estradiol potentiates the neurotrophic and neuroprotective effects mediated by the dopamine D3/acetylcholine nicotinic receptor heteromer in dopaminergic neurons

Dopaminergic neurons express a heteromer composed of the dopamine D3 receptor and the α4β2 nicotinic acetylcholine receptor, the D3R-nAChR heteromer, activated by both nicotine and dopamine D2 and D3 receptors agonists, such as quinpirole, and crucial for dopaminergic neuron homeostasis. We now report that D3R-nAChR heteromer activity is potentiated by 17-β-estradiol which acts as a positive allosteric modulator by binding a specific domain on the α4 subunit of the nicotinic receptor protomer. In mouse dopaminergic neurons, in fact, 17-β-estradiol significantly increased the ability of nicotine and quinpirole in promoting neuron dendritic remodeling and in protecting neurons against the accumulation of α-synuclein induced by deprivation of glucose, with a mechanism that does not involve the classical estrogen receptors. The potentiation induced by 17-β-estradiol required the D3R-nAChR heteromer since either nicotinic receptor or dopamine D3 receptor antagonists and interfering TAT-peptides, but not the estrogen receptor antagonist fulvestrant, specifically prevented 17-β-estradiol effects. Evidence of estrogens neuroprotection, mainly mediated by genomic mechanisms, have been provided, which is in line with epidemiological data reporting that females are less likely to develop Parkinson's Disease than males. Therefore, potentiation of D3R-nAChR heteromer activity may represent a further mechanism by which 17-β-estradiol reduces dopaminergic neuron vulnerability.

Nicotinic receptors in airway disease

With continued smoking of tobacco products and expanded use of nicotine delivery devices worldwide, understanding the impact of smoking and vaping on respiratory health remains a major global unmet need. Although multiple studies have shown a strong association between smoking and asthma, there is a relative paucity of mechanistic understanding of how elements in cigarette smoke impact the airway. Recognizing that nicotine is a major component in both smoking and vaping products, it is critical to understand the mechanisms by which nicotine impacts airways and promotes lung diseases such as asthma. There is now increasing evidence that α7 nicotinic acetylcholine receptors (α7nAChRs) are critical players in nicotine effects on airways, but the mechanisms by which α7nAChR influences different airway cell types have not been widely explored. In this review, we highlight and integrate the current state of knowledge regarding nicotine and α7nAChR in the context of asthma and identify potential approaches to alleviate the impact of smoking and vaping on the lungs.

Brain-Derived Neurotrophic Factor - The Protective Agent Against Neurological Disorders

The burden of neurological illnesses on global health is significant. Our perception of the molecular and biological mechanisms underlying intellectual processing and behavior has significantly advanced over the last few decades, laying the groundwork for potential therapies for various neurodegenerative diseases. A growing body of literature reveals that most neurodegenerative diseases could be due to the gradual failure of neurons in the brain's neocortex, hippocampus, and various subcortical areas. Research on various experimental models has uncovered several gene components to understand the pathogenesis of neurodegenerative disorders. One among them is the brain-derived neurotrophic factor (BDNF), which performs several vital functions, enhancing synaptic plasticity and assisting in the emergence of long-term thoughts. The pathophysiology of some neurodegenerative diseases, including Alzheimer's, Parkinson's, Schizophrenia, and Huntington's, has been linked to BDNF. According to numerous research, high levels of BDNF are connected to a lower risk of developing a neurodegenerative disease. As a result, we want to concentrate on BDNF in this article and outline its protective role against neurological disorders.

G Protein-Dependent Activation of the PKA-Erk1/2 Pathway by the Striatal Dopamine D1/D3 Receptor Heteromer Involves Beta-Arrestin and the Tyrosine Phosphatase Shp-2

The heteromer composed of dopamine D1 and D3 receptors (D1R-D3R) has been defined as a structure able to trigger Erk1/2 and Akt signaling in a G protein-independent, beta-arrestin 1-dependent way that is physiologically expressed in the ventral striatum and is likely involved in the control of locomotor activity. Indeed, abnormal levels of D1R-D3R heteromer in the dorsal striatum have been correlated with the development of L-DOPA-induced dyskinesia (LID) in Parkinson's disease patients, a motor complication associated with striatal D1R signaling, thus requiring Gs protein and PKA activity to activate Erk1/2. Therefore, to clarify the role of the D1R/D3R heteromer in LID, we investigated the signaling pathway induced by the heteromer using transfected cells and primary mouse striatal neurons. Collectively, we found that in both the cell models, D1R/D3R heteromer-induced activation of Erk1/2 exclusively required the D1R molecular effectors, such as Gs protein and PKA, with the contribution of the phosphatase Shp-2 and beta-arrestins, indicating that heterodimerization with the D3R abolishes the specific D3R-mediated signaling but strongly allows D1R signals. Therefore, while in physiological conditions the D1R/D3R heteromer could represent a mechanism that strengthens the D1R activity, its pathological expression may contribute to the abnormal PKA-Shp-2-Erk1/2 pathway connected with LID.

Recent Advances in Dopamine D3 Receptor Heterodimers: Focus on Dopamine D3 and D1 Receptor-Receptor Interaction and Striatal Function

G protein-coupled receptors (GPCR) heterodimers represent new entities with unique pharmacological, signalling, and trafficking properties, with specific distribution restricted to those cells where the two interacting receptors are co-expressed. Like other GPCR, dopamine D3 receptors (D3R) directly interact with various receptors to form heterodimers: data showing the D3R physical interaction with both GPCR and non-GPCR receptors have been provided including D3R interaction with other dopamine receptors. The aim of this chapter is to summarize current knowledge of the distinct roles of heterodimers involving D3R, focusing on the D3R interaction with the dopamine D1 receptor (D1R): the D1R-D3R heteromer, in fact, has been postulated in both ventral and motor striatum. Interestingly, since both D1R and D3R have been implicated in several pathological conditions, including schizophrenia, motor dysfunctions, and substance use disorders, the D1R-D3R heteromer may represent a potential drug target for the treatment of these diseases.