Gx-50 Inhibits Neuroinflammation via α7 nAChR Activation of the JAK2/STAT3 and PI3K/AKT Pathways

The Role of Alpha-7 Nicotinic Acetylcholine Receptors in Pain: Potential Therapeutic Implications

Chronic pain represents a prevalent and costly medical challenge globally. Nicotinic acetylcholine receptors (nAChRs), one type of ligand-gated ion channels found extensively in both the central and peripheral nervous systems, have emerged as promising therapeutic targets for chronic pain. Although there are currently no FDA-approved analgesics specifically targeting nAChRs, accumulating preclinical and clinical evidence suggest that selective ligands for alpha 7 (α7) nAChRs show potential for treating chronic pain, boasting a reduced incidence of side effects compared with other nicotinic receptor types. The recent structural resolution of human α7 nAChRs has confirmed their negative association with heightened pain, providing a valuable foundation for the development of targeted medications. This review presents a comprehensive overview, encompassing insights into the roles of α7 nAChRs derived from structural and functional studies, recent advancements in pharmacology, and investigations into their involvement in the pathophysiology of chronic pain. Moreover, the review addresses the variability in analgesic effects based on the type of receptor agonist and highlights the current research limitations. As such, this review offers potential therapeutic approaches for the development of innovative strategies for chronic pain management.

Insights into the advances in therapeutic drugs for neuroinflammation-related diseases

Studies have shown that neurodegenerative diseases such as AD and PD are related to neuroinflammation. Neuroinflammation is a common inflammatory condition that can lead to a variety of dysfunction in the body. At present, it is no medications specifically approved to prevent or cure neuroinflammation, so even though many drugs can temporarily control the neurological symptoms of neuroinflammation, but no one can reverse the progress of neuroinflammation, let al.one completely cure neuroinflammation. Therefore, it is urgent to develop new drug development for neuroinflammation treatment. In this review, we highlight the therapeutic advancement in the field of neurodegenerative disorders, by focusing on the impact of neuroinflammation treatment has on these conditions, and the effective drugs for the treatment of neuroinflammation and neurodegenerative diseases and their latest research progress are reviewed according to the related signaling pathway, as well as the prospect of their clinical application is also discussed. The purpose of this review is to enable specialists to better understand the mechanisms underlying neuroinflammation and anti-inflammatory drugs, promote the development of therapeutic drugs for neuroinflammation and neurodegenerative diseases, and further provide therapeutic references for clinical neurologists.

Lemairamin (Wgx-50) Attenuates DSS-Induced Intestinal Inflammation in Zebrafish

Inflammatory bowel disease (IBD) is a chronic non-specific intestinal inflammatory disease that affects millions of people worldwide, and current treatment methods have certain limitations. This study aimed to explore the therapeutic potential and mechanism of action of lemairamin (Wgx-50) in inflammatory bowel disease (IBD). We used dextran sulfate sodium (DSS)-treated zebrafish as an inflammatory bowel disease model, and observed the effect of Wgx-50 on DSS-induced colitis inflammation. The results of the study showed that Wgx-50 could reduce the expression of pro-inflammatory cytokines induced by DSS and inhibit the recruitment of neutrophils to the site of intestinal injury. Further experiments revealed that Wgx-50 exerted its anti-inflammatory effect by regulating the activation of the Akt pathway. These research findings indicate that Wgx-50 possesses anti-inflammatory activity.

V-set and immunoglobulin domain containing 4 inhibits oxidative stress, mitochondrial dysfunction, and inflammation to attenuate Parkinson's disease progression by activating the JAK2/STAT3 pathway

OBJECTIVE

V-set and immunoglobulin domain containing 4 (VSIG4) inhibits neurological dysfunction, microglial M1 polarization, and inflammation to participate in the progression of neurological disorders, but evidence regarding Parkinson's disease (PD) is scarce. The present study intended to investigate the engagement of VSIG4 in PD progression, and the potential mechanism.

METHODS

BV-2 cells were treated with 1-Methyl-4-phenylpyridinium (MPP+) to establish PD model. MPP+ treated BV-2 cells were infected with VSIG4 overexpression adenovirus-associated virus (AAV) (oeVSIG4) and negative control AAV (oeNC), and AZD1480 (JAK2 inhibitor) was added to these cells.

RESULTS

MPP+ reduced VSIG4 mRNA (P < 0.05) and protein (P < 0.05) in BV-2 cells. Interestingly, VSIG4 reduced malondialdehyde (P < 0.01), reactive oxygen species (P < 0.01), NOD-like receptor family pyrin domain containing 3 (P < 0.05), cleaved-caspase1 (P < 0.05), tumor necrosis factor-α (P < 0.05), and interleukin-1β (P < 0.05), but increased glutathione (P < 0.05), mitochondrial membrane potential (P < 0.05), phosphorylation (p)-JAK2 (P < 0.05), and p-STAT3 (P < 0.01) in MPP+ treated BV-2 cells, which indicated that VSIG4 inhibited oxidative stress, mitochondrial dysfunction, and inflammation, as well as activated the JAK2/STAT3 pathway in PD model. Moreover, AZD1480 inhibited the JAK2/STAT3 pathway and aggravated oxidative stress, mitochondrial dysfunction, and inflammation in PD model (all P < 0.05). Importantly, AZD1480 attenuated the influence of VSIG4 on oxidative stress, mitochondrial dysfunction, inflammation, and the JAK2/STAT3 pathway in PD model (all P < 0.05).

CONCLUSION

VSIG4 suppresses oxidative stress, mitochondrial dysfunction, and inflammation by activating the JAK2/STAT3 pathway, which may be helpful in attenuating PD progression.

Jiaohong pills attenuate neuroinflammation and amyloid-β protein-induced cognitive deficits by modulating the mitogen-activated protein kinase/nuclear factor kappa-B pathway

BACKGROUND

Jiaohong pills (JHP) consist of Pericarpium Zanthoxyli (PZ) and Radix Rehmanniae, two herbs that have been extensively investigated over many years due to their potential protective effects against cognitive decline and memory impairment. However, the precise mechanisms underlying the beneficial effects remain elusive. Here, research studies were conducted to investigate and validate the therapeutic effects of JHP on Alzheimer's disease.

METHODS

BV-2 cell inflammation was induced by lipopolysaccharide. AD mice were administered amyloid-β (Aβ). Behavioral experiments were used to evaluate learning and memory ability. The levels of nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-10 (IL-10) were detected using enzyme-linked immunosorbent assay (ELISA). The protein expressions of inducible nitric oxide synthase (iNOS) and the phosphorylation level of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) were detected using Western blot. Nissl staining was used to detect neuronal degeneration.

RESULTS

The results demonstrated that an alcoholic extract of PZ significantly decreased the levels of NO, IL-1β, TNF-α, and iNOS; increased the expression level of IL-10; and significantly decreased the phosphorylation levels of MAPK and NF-κB. These inhibitory effects were further confirmed in the AD mouse model. Meanwhile, JHP improved learning and memory function in AD mice, reduced neuronal damage, and enriched the Nissl bodies in the hippocampus. Moreover, IL-1β and TNF-α in the cortex were significantly downregulated after JHP administration, whereas IL-10 showed increased expression.

CONCLUSIONS

It was found that JHP reduced neuroinflammatory response in AD mice by targeting the MAPK/NF-κB signaling pathway.

WGX50 mitigates doxorubicin-induced cardiotoxicity through inhibition of mitochondrial ROS and ferroptosis

BACKGROUND

Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a major impediment to its clinical application. It is indispensable to explore alternative treatment molecules or drugs for mitigating DIC. WGX50, an organic extract derived from Zanthoxylum bungeanum Maxim, has anti-inflammatory and antioxidant biological activity, however, its function and mechanism in DIC remain unclear.

METHODS

We established DOX-induced cardiotoxicity models both in vitro and in vivo. Echocardiography and histological analyses were used to determine the severity of cardiac injury in mice. The myocardial damage markers cTnT, CK-MB, ANP, BNP, and ferroptosis associated indicators Fe2+, MDA, and GPX4 were measured using ELISA, RT-qPCR, and western blot assays. The morphology of mitochondria was investigated with a transmission electron microscope. The levels of mitochondrial membrane potential, mitochondrial ROS, and lipid ROS were detected using JC-1, MitoSOX™, and C11-BODIPY 581/591 probes.

RESULTS

Our findings demonstrate that WGX50 protects DOX-induced cardiotoxicity via restraining mitochondrial ROS and ferroptosis. In vivo, WGX50 effectively relieves doxorubicin-induced cardiac dysfunction, cardiac injury, fibrosis, mitochondrial damage, and redox imbalance. In vitro, WGX50 preserves mitochondrial function by reducing the level of mitochondrial membrane potential and increasing mitochondrial ATP production. Furthermore, WGX50 reduces iron accumulation and mitochondrial ROS, increases GPX4 expression, and regulates lipid metabolism to inhibit DOX-induced ferroptosis.

CONCLUSION

Taken together, WGX50 protects DOX-induced cardiotoxicity via mitochondrial ROS and the ferroptosis pathway, which provides novel insights for WGX50 as a promising drug candidate for cardioprotection.

Microglia and cognitive impairment in schizophrenia: translating scientific progress into novel therapeutic interventions

Cognitive impairment is a core clinical feature of schizophrenia, exerting profound adverse effects on social functioning and quality of life in a large proportion of patients with schizophrenia. However, the mechanisms underlying the pathogenesis of schizophrenia-related cognitive impairment are not well understood. Microglia, the primary resident macrophages in the brain, have been shown to play important roles in psychiatric disorders, including schizophrenia. Increasing evidence has revealed excessive microglial activation in cognitive deficits related to a broad range of diseases and medical conditions. Relative to that about age-related cognitive deficits, current knowledge about the roles of microglia in cognitive impairment in neuropsychiatric disorders, such as schizophrenia, is limited, and such research is in its infancy. Thus, we conducted this review of the scientific literature with a focus on the role of microglia in schizophrenia-associated cognitive impairment, aiming to gain insight into the roles of microglial activation in the onset and progression of such impairment and to consider how scientific advances could be translated to preventive and therapeutic interventions. Research has demonstrated that microglia, especially those in the gray matter of the brain, are activated in schizophrenia. Upon activation, microglia release key proinflammatory cytokines and free radicals, which are well-recognized neurotoxic factors contributing to cognitive decline. Thus, we propose that the inhibition of microglial activation holds potential for the prevention and treatment of cognitive deficits in patients with schizophrenia. This review identifies potential targets for the development of new treatment strategies and eventually the improvement of care for these patients. It might also help psychologists and clinical investigators in planning future research.

Targeting α7-nAChR by galantamine mitigates reserpine-induced fibromyalgia-like symptoms in rats: Involvement of cAMP/PKA, PI3K/AKT, and M1/M2 microglia polarization

Fibromyalgia (FM) is a pain disorder marked by generalized musculoskeletal pain accompanied by depression, fatigue, and sleep disturbances. Galantamine (Gal) is a positive allosteric modulator of neuronal nicotinic acetylcholine receptors (nAChRs) and a reversible inhibitor of cholinesterase. The current study aimed to explore the therapeutic potential of Gal against reserpine (Res)-induced FM-like condition along with investigating the α7-nAChR's role in Gal-mediated effects. Rats were injected with Res (1 mg/kg/day; sc) for 3 successive days then Gal (5 mg/kg/day; ip) was given alone and with the α7-nAChR blocker methyllycaconitine (3 mg/kg/day; ip), for the subsequent 5 days. Galantamine alleviated Res-induced histopathological changes and monoamines depletion in rats' spinal cord. It also exerted analgesic effect along with ameliorating Res-induced depression and motor-incoordination as confirmed by behavioral tests. Moreover, Gal produced anti-inflammatory effect through modulating AKT1/AKT2 and shifting M1/M2 macrophage polarization. The neuroprotective effects of Gal were mediated through activating cAMP/PKA and PI3K/AKT pathways in α7-nAChR-dependent manner. Thus, Gal can ameliorate Res-induced FM-like symptoms and mitigate the associated monoamines depletion, neuroinflammation, oxidative stress, apoptosis, and neurodegeneration through α7-nAChR stimulation, with the involvement of cAMP/PKA, PI3K/AKT, and M1/M2 macrophage polarization.

Treatment of Neuropathic Pain Directly Due to Cancer: An Update

Simple Summary

This review discusses treatment approaches for providing pain relief to oncological patients affected by pain caused by nerve damage due to the tumor, also known as neuropathic cancer pain. Although being encountered often and causing a relevant burden to these patients, neuropathic cancer pain remains still difficult to diagnose and treat. Strong evidence about the best drugs to be used remain limited, as do therapeutic choices.

Abstract

Neuropathic pain can be defined as pain related to abnormal somatosensory processing in either the peripheral or central nervous system. In this review article, with neuropathic cancer pain (NCP), we refer to pain due to nervous tissue lesions caused by the tumor or its metastases. Nervous tissue damage is the cause of cancer pain in approximately 40% of those experiencing cancer pain. Recognizing a neuropathic pathophysiology in these cases may be difficult and requires specific criteria that are not homogenously applied in clinical practice. The management of this type of pain can be challenging, requiring the use of specific non-opioid adjuvant drugs. The majority of the criteria for NCP diagnosis and management have been based mainly on results from the noncancer population, risking the failure of addressing the specific needs of this population of patients. In this review, we summarize current management options available for NCP and provide some insights on new promising treatments.

New AKT-dependent mechanisms of anti-COVID-19 action of high-CBD Cannabis sativa extracts

COVID-19 is caused by the SARS-CoV-2 virus, which enters target cells via interactions with ACE2 and TMPRSS2. Here, we show AKT serine/threonine kinase-dependent epigenetic control of ACE2 and TMPRSS2 expression by high-cannabidiol (CBD) cannabis extracts and their individual components. CBD alone and extracts #1, #5, #7, and #129 downregulated ACE2 and TMPRSS2 in lung fibroblast WI-38 cells through AKT-mediated inhibition. miR-200c-3p and let-7a-5p were two contributing miRNAs in CBD-mediated suppression of ACE2 and TMPRSS2. CBD and terpene PTWT2.2 profoundly inhibited ACE2 and TMPRSS2 expression, both individually and in combination. Extracts #1, #5, #7, and #169 suppressed COX2 expression and remarkably attenuated TNFα/IFNγ-triggered induction of proinflammatory factors IL-6 and IL-8 by AKT pathway. The most abundant molecules present in extracts #1 and #7 modulated the expression of COX2, IL-6, and IL-8 both individually and in combination. These results reveal that high-CBD cannabis extracts attenuated ACE2 and TMPRSS2 expression and the induction of inflammatory mediators COX2, IL-6, and IL-8 via the AKT pathway, highlighting their potential anti-COVID-19 features.

Altered Brain Cholinergic and Synaptic Markers in Obese Zucker Rats

The association between obesity and loss of cognitive performance has been recognized. Although there are data regarding the metabolic alterations in obese conditions and the development of neuroinflammation, no clear evidence concerning obesity-related cholinergic and synaptic impairments in the frontal cortex and hippocampus has been reported yet. Here, we investigate different cholinergic and synaptic markers in 12-, 16-, and 20-week-old obese Zucker rats (OZRs) compared with lean littermate rats (LZRs), using immunochemical and immunohistochemical analysis. Consequently, OZRs showed body weight gain, hypertension, and dysmetabolism. In 20-week-old OZRs, the reduction of vesicular acetylcholine transporter (VAChT) and alpha7 nicotinic acetylcholine receptors (α7nAChR) occurred both in the frontal cortex and in the hippocampus, suggesting a cognitive dysfunction due to obesity and aging. Among the muscarinic receptors analyzed, the level of expression of type 1 (mAChR1) was lower in the hippocampus of the older OZRs. Finally, we showed synaptic dysfunctions in OZRs, with a reduction of synaptophysin (SYP) and synaptic vesicle glycoprotein 2B (SV2B) in 20-week-old OZRs, both in the frontal cortex and in the hippocampus. Taken together, our data suggest specific alterations of cholinergic and synaptic markers that can be targeted to prevent cognitive deficits related to obesity and aging.

Inflammatory pathways in Alzheimer's disease mediated by gut microbiota

In the past decade, numerous studies have demonstrated the close relationship between gut microbiota and the occurrence and development of Alzheimer's disease (AD). However, the specific mechanism is still unclear. Both the neuroinflammation and systemic inflammation serve as the key hubs to accelerate the process of AD by promoting pathology and damaging neuron. What's more, the gut microbiota is also crucial for the regulation of inflammation. Therefore, this review focused on the role of gut microbiota in AD through inflammatory pathways. Firstly, this review summarized the relationship and interaction among gut microbiota, inflammation, and AD. Secondly, the direct and indirect regulatory effects of gut microbiota on AD through inflammatory pathways were described. These effects were mainly mediated by the component of the gut microbiota (lipopolysaccharides (LPS) and amyloid peptides), the metabolites of bacteria (short-chain fatty acids, branched amino acids, and neurotransmitters) and functional by-products (bile acids). In addition, potential treatments (fecal microbiota transplantation, antibiotics, probiotics, prebiotics, and dietary interventions) for AD were also discussed through these mechanisms. Finally, according to the current research status, the key problems to be solved in the future studies were proposed.

Protective Effects of Aquaporin-4 Deficiency on Longer-term Neurological Outcomes in a Mouse Model

Traumatic brain injury (TBI) has been a crucial health problem, with more than 50 million patients worldwide each year. Glymphatic system is a fluid exchange system that relies on the polarized water channel aquaporin-4 (AQP4) at the astrocytes, accounting for the clearance of abnormal proteins and metabolites from brain tissues. However, the dysfunction of glymphatic system and alteration of AQP4 polarization during the progression of TBI remain unclear. AQP4-/- and Wild Type (WT) mice were used to establish the TBI mouse model respectively. Brain edema and Evans blue extravasation were conducted 24 h post-injury to evaluate the acute TBI. Morris water maze (MWM) was used to establish the long-term cognitive functions of AQP4-/- and WT mice post TBI. Western-blot and qRT-PCR assays were performed to demonstrate protective effects of AQP4 deficiency to blood-brain barrier (BBB) integrity and amyloid-β clearance. The inflammation of cerebral tissues post TBI was estimated by ELISA assay. AQP4 deficiency alleviated the brain edema and neurological deficit in TBI mice. AQP4-knockout led to improved cognitive outcomes in mice post TBI. The BBB integrity and cerebral amyloid-β clearance were protected by AQP4 deficiency in TBI mice. AQP4 deficiency ameliorated the TBI-induced inflammation. AQP4 deficiency improved longer-term neurological outcomes in a mouse model of TBI.

Cellular responses and functions of α7 nicotinic acetylcholine receptor activation in the brain: a narrative review

The α7 nicotinic acetylcholine receptor (α7nAChR) has been studied for many years since its discovery. Although many functions and characteristics of brain α7nAChR are widely understood, much remains to be elucidated. The α7nAChR is widely expressed in the central nervous system, not only in neurons but also in astrocytes, microglia, and endothelial cells. α7nAChR can be activated by endogenous agonist like acetylcholine or exogenous agonists like nicotine and PNU282987. Its agonists can be divided into selective agonists and non-selective agonists. The activation of α7nAChR results in a series of physiological processes which have both short-term and long-term effects on cells, for example, calcium influx, neurotransmitter release, synaptic plasticity, and excitatory transmission. It also induces other downstream events, such as inflammation, autophagy, necrosis, transcription, and apoptosis. The cellular responses to α7nAChR activation vary according to cell types and conditions. For example, α7nAChR activation in pyramidal neurons leads to long-term potentiation, while α7nAChR activation in GABAergic interneurons leads to long-term depression. Studies have also shown some contradictory phenomena, which requires further study for clarification. Herein, the cellular responses of α7nAChR activation are summarized, and the functions of α7nAChR in neurons and non-neuronal cells are discussed. We also summarized contradictory conclusions to show where we stand and where to go for future studies.

Cynandione A Alleviates Neuropathic Pain Through α7-nAChR-Dependent IL-10/β-Endorphin Signaling Complexes

Cynandione A, an acetophenone isolated from Cynanchum Wilfordii Radix, exhibits antineuropathic pain effect. This study further explored the target molecule and signaling mechanisms underlying cynandione-A-induced antineuropathic pain. Intrathecal injection of cynandione A significantly attenuated mechanical allodynia in neuropathic rats and substantially increased spinal expression of IL-10 and β-endorphin but not dynorphin A. Cynandione A treatment also enhanced expression of IL-10 and β-endorphin but not α7 nicotinic acetylcholine receptors (nAChRs) in cultured microglia. The IL-10 antibody attenuated cynandione-A-induced spinal or microglial gene expression of β-endorphin and mechanical allodynia, whereas the β-endorphin antiserum blocked cynandione-A-induced mechanical antiallodynia but not spinal or microglial IL-10 gene expression. The α7 nAChR antagonist methyllycaconitine significantly reduced cynandione-A-induced mechanical antiallodynia and spinal or microglial expression of IL-10 and β-endorphin. Furthermore, cynandione A stimulated microglial phosphorylation of PKA, p38, and CREB in an α7-nAChR-dependent manner, and treatment with their inhibitors attenuated cynandione-A-induced mechanical antiallodynia and spinal or microglial expression of IL-10 and β-endorphin. In addition, cynandione A stimulated spinal phosphorylation of the transcription factor STAT3, which was inhibited by methyllycaconitine, the PKA activation inhibitor or IL-10 antibody. The STAT3 inhibitor NSC74859 also abolished cynandione-A-induced mechanical antiallodynia and spinal expression of β-endorphin. These findings suggest that cynandione A suppresses neuropathic pain through α7-nAChR-dependent IL-10/β-endorphin signaling pathway in spinal microglia.

Cardioprotective role of GTS-21 by attenuating the TLR4/NF-κB pathway in streptozotocin-induced diabetic cardiomyopathy in rats

The cholinergic anti-inflammatory pathway (CAP) was investigated in a variety of inflammatory conditions and constitutes a valuable line in their treatment. In the current study, we investigated the anti-inflammatory effect of GTS-21 (GTS) as a partial selective α7 nicotinic acetylcholine receptor (α7-nAchR) agonist in diabetic cardiomyopathy model in rats. This mechanism was elaborated to study whether it could alleviate the electrocardiographic, histopathological, and molecular levels of Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway proteins. Diabetes was induced by the injection of streptozotocin (STZ) (50 mg/kg). Diabetic rats were treated with GTS (1 or 2 mg/kg/day), methyllycaconitine (MLA), a selective α7-nAchR antagonist (2 mg/kg/day) plus GTS (2 mg/kg/day), or the vehicle. All treatments were given by the intraperitoneal route. Ventricular rate and different electrocardiograph (ECG) anomalies were detected. Plasma levels of cardiac troponin T (cTnT) and creatine kinase MB (CK-MB) were measured by ELISA. Additionally, we elucidated the levels of several proteins involved in the TLR4/NF-κB pathway. Cardiac levels of TLR4 and phosphorylated protein kinase B (p-Akt) were detected by ELISA. The cardiac expression of myeloid differentiation primary response 88 (Myd88), tumor necrosis factor receptor-associated factor 6 (TRAF6), NF-κB, interleukin 1β (IL-1β), and active caspase-1 were evaluated by immunohistochemical staining. Finally, the cardiac levels of interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. Diabetic rats showed (i) ECG signs of cardiomyopathy such as significant ST segment elevations, prolonged QRS, QT intervals, and ventricular tachycardia; (ii) increased plasma levels of cTnT and CK-MB; (iii) increased expression of cardiac TLR4; (iv) elevated immunohistochemical expression of cardiac, Myd88, TRAF6, and NF-κB; (v) diminution in the cardiac expression of p-Akt; and (vi) adaptive increases in cardiac expression of TNF-α and IL-6. These effects were ameliorated in diabetic rats treated with both doses of GTS. Pretreatment with MLA did not completely reverse the ameliorative effect of GTS on cTnT, TRAF6, TNF-α, and IL-6, thereby reinforcing the presence of possible α7-nAchR-independent mechanisms. The activation of α7-nAchR with GTS offers a promising prophylactic strategy for diabetic cardiomyopathy by attenuating the TLR4/NF-κB pathway.

Aging-related modifications to G protein-coupled receptor signaling diversity

Aging is a highly complex molecular process, affecting nearly all tissue systems in humans and is the highest risk factor in developing neurodegenerative disorders such as Alzheimer's and Parkinson's disease, cardiovascular disease and Type 2 diabetes mellitus. The intense complexity of the aging process creates an incentive to develop more specific drugs that attenuate or even reverse some of the features of premature aging. As our current pharmacopeia is dominated by therapeutics that target members of the G protein-coupled receptor (GPCR) superfamily it may be prudent to search for effective anti-aging therapeutics in this fertile domain. Since the first demonstration of GPCR-based β-arrestin signaling, it has become clear that an enhanced appreciation of GPCR signaling diversity may facilitate the creation of therapeutics with selective signaling activities. Such 'biased' ligand signaling profiles can be effectively investigated using both standard molecular biological techniques as well as high-dimensionality data analyses. Through a more nuanced appreciation of the quantitative nature across the multiple dimensions of signaling bias that drugs possess, researchers may be able to further refine the efficacy of GPCR modulators to impact the complex aberrations that constitute the aging process. Identifying novel effector profiles could expand the effective pharmacopeia and assist in the design of precision medicines. This review discusses potential non-G protein effectors, and specifically their potential therapeutic suitability in aging and age-related disorders.

Inhibition of RNF6 alleviates traumatic brain injury by suppressing STAT3 signaling in rats

BACKGROUND

Traumatic brain injury (TBI) has ranked as one of the leading causes of disability and death in the world. The neuroinflammation mediated by signal transducer and activator of transcription 3 (STAT3) signaling during the progression of TBI leads to long-term neurodegeneration. Ring finger protein 6 (RNF-6) is an E3 ubiquitin ligase and can regulate the activity of STAT3 signaling pathway by targeting its inhibitors. However, the mechanism underlying this process in TBI remains poorly understood.

METHODS

In this research, cortical impact injury was used to construct the TBI rat model. Western blot assay was performed to evaluate the protein levels of RNF6, Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1), and STAT3/pSTAT3. QRT-PCR assay was performed to assess the RNA levels of RNF6 and other cytokines. The neural function of TBI rats was estimated by modified Neurological Severity Scores test.

RESULTS

The expression of RNF-6 was up-regulated in the brain tissues of TBI rats. Down-regulation of RNF6 alleviated the symptoms and improved the neural recovery postinjury in TBI rats. Inhibition of RNF6 suppressed the cerebral inflammation by up-regulating the protein level of SHP-1 and down-regulating the phosphorylation level of STAT3.

CONCLUSION

Inhibition of RNF6 alleviated TBI by suppressing the STAT3 signaling in TBI rats.

[Establishment of a gp120 transgenic mouse model with α7 nAChR knockout]

OBJECTIVE

To construct a HIV-1 gp120 transgenic mouse model (gp120+) with α7 nicotinic acetylcholine receptor (α7nAChR) gene knockout.

METHODS

The α7nAChR gene knockout mice (α7R-/-) were crossed with HIV-1gp120 transgenic mice (gp120+) to generate F1 generation mice. We selected the F1 mice with the genotype of α7R+/-/gp120+ to mate to obtain the F2 mice. The genotypes of the F3 mice were identified by PCR, and the protein expressions in the double transgenic animal model was analyzed by immunohistochemistry. BV2 cells were treated with gp120 protein and α7nAChR inhibitor, and the expressions of IL-1β and TNF-α were detected using ELISA.

RESULTS

The results of PCR showed the bands of the expected size in F3 mice. Two F3 mice with successful double gene editing (α7R-/-/gp120+) were obtained, and immunohistochemistry showed that the brain tissue of the mice did not express α7 nAChR but with high gp120 protein expression. In the in vitro cell experiment, treatment with gp120 promoted the secretion of IL-1β and TNF-α in BV2 cells, while inhibition of α7nAChR significantly decreased the expression of IL-1β and TNF-α (P < 0.001).

CONCLUSIONS

By mating gp120 Tg mice with α7R-/- mice, we obtained gp120 transgenic mice with α7nAChR gene deletion, which serve as a new animal model for exploring the role of α7nAChR in gp120-induced neurotoxicity.

Oxidative Stress and Neuroinflammation Potentiate Each Other to Promote Progression of Dopamine Neurodegeneration

Parkinson's disease (PD) is a chronic and complex disease of the central nervous system (CNS). Progressive loss of dopamine (DA) neurons in midbrain substantia nigra is considered to be the main cause of PD. The hallmark of PD pathology is the formation of Lewy bodies and the deposition of α-synuclein (α-syn). The mechanisms responsible for the progressive feature of DA neurodegeneration are not fully illustrated. Recently, oxidative stress and neuroinflammation have received extensive attention as two important entry points in the pathogenesis of PD. The occurrence of oxidative stress and neuroinflammation is usually derived from external influences or changes in internal environment, such as the accumulation of reactive oxygen species, exposure to a toxic environment, and the transformation of systemic inflammation. However, PD never results from a single independent factor and the simultaneous participation of oxidative stress and neuroinflammation contributed to PD development. Oxidative stress and neuroinflammation could potentiate each other to promote progression of PD. In this review, we briefly summarized the conditions of oxidative stress and neuroinflammation and the crosstalk between oxidative stress and neuroinflammation on the development of PD.

Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease

INTRODUCTION

Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice.

AREAS COVERED

(i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations.

EXPERT OPINION

The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.

Kappa opioid receptor agonists improve postoperative cognitive dysfunction in rats via the JAK2/STAT3 signaling pathway

Postoperative cognitive dysfunction (POCD) is a common and well‑known complication following surgery, particularly cardiopulmonary bypass (CPB) surgery. There are currently no suitable treatments for POCD, which is associated with increased illness and mortality rates. The present study aimed to identify a novel treatment for POCD. The protective effect of kappa opioid receptor (KOR) agonists on POCD in rats following CPB was determined and the regulatory mechanism of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway was examined. The rats were randomly divided into five groups: Sham operation (Sham group), CPB operation (CPB group), KOR agonist + CPB (K group), KOR agonist + norbinaltorphimine (nor‑BNI) + CPB (NK group), and KOR agonist + JAK2‑STAT3 specific pathway inhibitor + CPB (AG group). A water maze test and neurological function scores were used to evaluate POCD. Hematoxylin and eosin staining was used to observe hippocampal neurons. ELISA was used to detect the levels of inflammatory factors, oxidative stress factors and brain injury markers. Immunofluorescence was used to visualize the neurons. TUNEL staining and western blotting were used to detect neuronal apoptosis, and western blotting was also used to detect JAK2/STAT3 pathway‑related proteins. The KOR agonists significantly improved POCD. S‑100β and NSE detection revealed that KOR agonists alleviated brain damage in CPB rats, and this result was reversed by KOR antagonists. The KOR agonists led to a significantly reduced inflammatory response and oxidative stress, as determined by ELISA detection, and attenuated hippocampal neuronal apoptosis, as revealed by TUNEL staining and western blotting, compared with the results in the CPB group. Finally, the KOR agonists inhibited the expression levels of phosphorylated (p‑)JAK2 and p‑STAT3, rather than total JAK2 and STAT3, compared with levels in the CPB group. Taken together, KOR agonists improved POCD in rats with CPB by inhibiting the JAK2/STAT3 signaling pathway.

GTS-21 Protected Against LPS-Induced Sepsis Myocardial Injury in Mice Through α7nAChR

Sepsis-induced myocardial injury is a well-known cause of mortality. The cholinergic anti-inflammatory pathway (CHAIP) is a physiological mechanism by which the central nervous system regulates immune response through the vagus nerve and acetylcholine; the α7-nicotinic acetylcholine receptor (α7nAChR) is the main component of CHAIP; GTS-21, a synthetic α7nAChR selective agonist, has repeatedly shown its powerful anti-inflammatory effect. However, little is known about its effect on LPS-induced myocardial injury. We investigated the protective effects of GTS-21 on lipopolysaccharide (LPS)-induced cardiomyopathy via the cholinergic anti-inflammatory pathway in a mouse sepsis model. We constructed the model of myocardial injury in sepsis mice by C57BL/6 using LPS and determined the time of LPS treatment by hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). C57BL/6 mice were randomized into five groups: blank control group, model group, α-bungarotoxin + LPS group, GTS-21 + LPS group, and α-bungarotoxin + GTS-21 + LPS group. The pathological results of myocardial tissue were detected by the HE method; the apoptosis rate was detected by the TUNEL method; the relative expressions of NF-κB p65, Caspase-3, Caspase-8, Bcl-2, Bax, p53, and a7nAChR were detected by real-time quantitative PCR (RT-PCR); and the protein expressions of IL-6, IL-1 β, TNF-α, and pSTAT3 were detected by western blot. The results showed that LPS-induced myocardial pathological and apoptosis changes were significant compared with the blank group, which was reversed by GTS-21; however, pretreatment with α-bungarotoxin obviously blocked the protective effect of GTS-21. NF-κB p65, Caspase-3, Caspase-8, Bax, p53, IL-6, IL-1β, TNF-α, and pSTAT3 were significantly increased in the model group, while a7nAChR and Bcl-2 were significantly decreased; GTS-21 treatment reversed that result, while pretreatment with α-bungarotoxin strengthened the result in the model. And pretreatment with α-bungarotoxin blocked the protective effect of GTS-21. GTS-21 can alleviate the LPS-induced damage in the heart via a7nAChR, and pretreatment with α-bungarotoxin obviously blocked the protective effect of GTS-21 on sepsis in mice.

α7 Nicotinic acetylcholine receptor-mediated anti-inflammatory effect in a chronic migraine rat model via the attenuation of glial cell activation

Background

Evidence suggests that the activation of α7 nicotinic acetylcholine receptor (α7nAChR) can greatly decrease the neuroinflammation response. Neuroinflammation plays a pivotal role in the pathogenesis of chronic migraine (CM). Clinical observations also show that nicotine gum induces analgesic effects in migraine patients. However, whether α7nAChR is involved in CM is unclear.

Objective

To investigate the role of α7nAChR in CM and provide a new therapeutic target for CM.

Materials and methods

Thirty-six male Sprague–Dawley rats were distributed randomly into control, CM, PNU-282987, and α-bungarotoxin groups (n=9 rats in each group). The CM model was established by the recurrent daily administration of inflammatory soup on the dura over the course of 1 week. The hind paw threshold and facial allodynia were assessed by the von Frey test. The expression levels of α7nAChR, tumor necrosis factor-alpha, and interleukin-1 beta were analyzed by Western blot and real-time fluorescence quantitative polymerase chain reaction. The location of α7nAChR in the hippocampus was quantified by immunofluorescence, as well as the microglial and astrocyte alterations. Changes in the calcitonin gene-related peptide and the phosphorylated JNK protein among different groups were measured by Western blot.

Results

We found that the expression of α7nAChR was reduced after repeated inflammatory soup administration. The increased expression of tumor necrosis factor-alpha, interleukin-1 beta, and calcitonin gene-related peptide in CM group were significantly decreased by PNU-282987 and aggravated by α-bungarotoxin. Moreover, PNU-282987 decreased the numbers of astrocytes and microglia compared with the numbers in the CM group in both hippocampal CA1 and CA3 regions. In contrast, α-bungarotoxin activated the astrocytes and microglia, but the differences with respect to the CM group were not significant. Activated c-Jun N-terminal kinase signaling was observed in CM rats and was also blocked by PNU-282987.

Conclusion

The activation of α7nAChR increased the mechanical threshold and alleviated pain in the CM rat model. α7nAChR activation also decreased the upregulation of astrocytes and microglia through the p-c-Jun N-terminal kinase–mitogen-activated protein kinase signaling pathway.

S-glutathionylation exerts opposing roles in the regulation of STAT1 and STAT3 signaling in reactive microglia

STAT1 and STAT3 are two transcription factors involved in a lot of cellular functions such as immune response, proliferation, apoptosis, and cell survival. A number of literature evidences described a yin-yang relationship between activation of STAT1 and STAT3 in neurodegenerative disorders where STAT1 exerts a pro-apoptotic effect whereas STAT3 shows neuroprotective properties through the inhibition of apoptosis. Although the role of oxidative-stress in the pathogenesis of neurodegeneration is clearly described, its influence in the regulation of these pathways is poorly understood. Herein, we demonstrate that H₂O₂ rapidly induces phosphorylation of STAT1 whereas it is not able to influence phosphorylation of STAT3 in mouse microglia BV2 cells. The analysis of the molecular mechanism of STATs signaling reveals that H₂O₂ induces S-glutathionylation of both STAT1 and STAT3. The same post-translational event exerts an opposing role in the regulation of STAT1 and STAT3 signaling. These data not only confirm redox sensibility of STAT3 signaling but also reveal for the first time that STAT1 is susceptible to redox regulation. A deep study of the molecular mechanism of STAT1 redox regulation, identifies Cys324 and Cys492 as the main targets of S-glutathionylation and confirms that S-glutathionylation does not impair JAK2 mediated STAT1 tyrosine phosphorylation. These results demonstrate that both phosphorylation and glutathionylation contribute to activation of STAT1 during oxidative stress and underline that the same post-translation event exerts an opposing role in the regulation of STAT1 and STAT3 signaling in microglia cells.

Cotinine: A Therapy for Memory Extinction in Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a mental disorder that may develop after exposure to exceptionally threatening or unescapable horrifying events. Actual therapies fail to alleviate the emotional suffering and cognitive impairment associated with this disorder, mostly because they are ineffective in treating the failure to extinguish trauma memories in a great percentage of those affected. In this review, current behavioral, cellular, and molecular evidence supporting the use of cotinine for treating PTSD are reviewed. The role of the positive modulation by cotinine of the nicotinic acetylcholine receptors (nAChRs) and their downstream effectors, the protection of astroglia, and the inhibition of microglia in the PTSD brain are also discussed.

miR-124-3p attenuates MPP+-induced neuronal injury by targeting STAT3 in SH-SY5Y cells

Ample evidence has demonstrated the involvement of microRNAs in Parkinson's disease pathogenesis. miR-124-3p was reported to be able to improve neural functional recovery. However, the underlying mechanism of miR-124-3p in Parkinson's disease progression was not well established. This study was designed to investigate the role of miR-124-3p in methyl phenyl pyridinium iodide (MPP)+-induced SH-SY5Y cells, an in vitro Parkinson's disease model. It is observed that miR-124-3p expression was decreased, and STAT3 expression was increased in MPP+-induced SH-SY5Y cells. miR-124-3p overexpression attenuated MPP+-induced neuronal injury, displayed as increased cell viability and superoxide dismutase activities, as well as reduced cell apoptosis, Caspase-3 activity, lactate dehydrogenase activity, inflammatory factors TNF-α, and IL-1β levels and reactive oxygen species generation. Moreover, STAT3 was confirmed to be a miR-124-3p target. Restored STAT3 expression reversed miR-124-3p-induced neuroprotective effects against MPP+-mediated neuronal injury. These data demonstrated that miR-124-3p contributed to neuroprotective effects in MPP+-induced Parkinson's disease cell model by targeting STAT3. Impact statement PD affects millions of people in the world, causing uncontrolled tremors. MicroRNAs, a class of endogenous single-stranded non-coding transcript with approximately 22 nucleotides, could bind to the 3″ UTR of their targets. The functional action of miR-124-3p in PD was not fully elucidated. Our study found that ectopic expression miR-124-3p attenuated MPP+-induced injury in PD model in vitro by suppressing neurotoxicity, neuronal apoptosis, neuroinflammation, and oxidative stress. Moreover, we validated that miR-124-3p could bind to STAT3 mediating the neuroprotective effect of miR-124-3p. We believe this study will be interesting for readers of this area.

Receptor for advanced glycation end products mediates sepsis-triggered amyloid-β accumulation, Tau phosphorylation, and cognitive impairment

Patients recovering from sepsis have higher rates of CNS morbidities associated with long-lasting impairment of cognitive functions, including neurodegenerative diseases. However, the molecular etiology of these sepsis-induced impairments is unclear. Here, we investigated the role of the receptor for advanced glycation end products (RAGE) in neuroinflammation, neurodegeneration-associated changes, and cognitive dysfunction arising after sepsis recovery. Adult Wistar rats underwent cecal ligation and perforation (CLP), and serum and brain (hippocampus and prefrontal cortex) samples were obtained at days 1, 15, and 30 after the CLP. We examined these samples for systemic and brain inflammation; amyloid-β peptide (Aβ) and Ser-202-phosphorylated Tau (p-Tau^Ser-202) levels; and RAGE, RAGE ligands, and RAGE intracellular signaling. Serum markers associated with the acute proinflammatory phase of sepsis (TNFα, IL-1β, and IL-6) rapidly increased and then progressively decreased during the 30-day period post-CLP, concomitant with a progressive increase in RAGE ligands (S100B, Nϵ-[carboxymethyl]lysine, HSP70, and HMGB1). In the brain, levels of RAGE and Toll-like receptor 4, glial fibrillary acidic protein and neuronal nitric-oxide synthase, and Aβ and p-Tau^Ser-202 also increased during that time. Of note, intracerebral injection of RAGE antibody into the hippocampus at days 15, 17, and 19 post-CLP reduced Aβ and p-Tau^Ser-202 accumulation, Akt/mechanistic target of rapamycin signaling, levels of ionized calcium-binding adapter molecule 1 and glial fibrillary acidic protein, and behavioral deficits associated with cognitive decline. These results indicate that brain RAGE is an essential factor in the pathogenesis of neurological disorders following acute systemic inflammation.

Activating α7 nicotinic acetylcholine receptor inhibits NLRP3 inflammasome through regulation of β-arrestin-1

AIMS

To evaluate whether activating α7 nicotinic acetylcholine receptor (α7nAChR) could inhibit the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome through regulation of β-arrestin-1 in monocyte/macrophage system, thus contributing to the control of neuroinflammation.

METHODS

The protein levels of NLRP3, caspase-1 (Casp-1) p20 and proCasp-1, interleukin-1β (IL-1β) p17 and proIL-1β, IL-18 and proIL-18 were measured using Western blotting. The mRNA levels of Casp-1 and IL-1β were detected by real-time PCR (RT-PCR). The colocalization and interaction of NLRP3 protein and β-arrestin-1 were measured by immunofluorescence staining and immunoprecipitation.

RESULTS

The expression of β-arrestin-1 was significantly increased and colocalized with CD45-positive cells in spinal cord of experimental auto-immune encephalomyelitis (EAE) mice when compared with the sham mice, which was attenuated by pretreatment with PNU282987, a specific α7nAChR agonist. PNU282987 also significantly inhibited the activation of NLRP3 inflammasome and thus decreased the production of IL-1β and IL-18 both in lipopolysaccharide (LPS)/ATP-stimulated BV2 microglia in vitro and spinal cord from EAE mice in vivo, while inverse effects were observed in α7nAChR knockout mice. Furthermore, overexpression of β-arrestin-1 attenuated the inhibitory effect of PNU282987 on NLRP3 inflammasome activation in LPS/ATP-stimulated BV2 microglia. PNU282987 inhibited the interaction between β-arrestin-1 and NLRP3 protein in vitro.

CONCLUSIONS

The present study demonstrates that activating α7nAChR can lead to NLRP3 inflammasome inhibition via regulation of β-arrestin-1 in monocyte/microglia system.

RETRACTED: The effects of tanshinone IIA on hypoxia/reoxygenation-induced myocardial microvascular endothelial cell apoptosis in rats via the JAK2/STAT3 signaling pathway

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. An Expression of Concern for this article was previously published while an investigation was conducted (see related editorial: https://doi.org/10.1016/j.biopha.2022.113812). This retraction notice supersedes the Expression of Concern published earlier. Concern was raised about the reliability of the flow cytometry data shown in Figures 5, 7, and 8, which appears to contain similar repeating features, as detailed here: https://pubpeer.com/publications/B7A8CA625357F2A4DCEAC0E5AA276A; and here https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Independent analysis confirmed these findings and also identified additional suspected image duplications within the β-actin bands in Figure 9A, and between the Bcl-2 and Bax-2 Western blots in Figure 10A. The journal requested the corresponding author comment on these concerns and provide the associated raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.