Regulation of B cell functions by S-nitrosoglutathione in the EAE model

Sterile inflammation induces vasculopathy and chronic lung injury in murine sickle cell disease

Murine sickle cell disease (SCD) results in damage to multiple organs, likely mediated first by vasculopathy. While the mechanisms inducing vascular damage remain to be determined, nitric oxide bioavailability and sterile inflammation are both considered to play major roles in vasculopathy. Here, we investigate the effects of high mobility group box-1 (HMGB1), a pro-inflammatory damage-associated molecular pattern (DAMP) molecule on endothelial-dependent vasodilation and lung morphometrics, a structural index of damage in sickle (SS) mice. SS mice were treated with either phosphate-buffered saline (PBS), hE-HMGB1-BP, an hE dual-domain peptide that binds and removes HMGB1 from the circulation via the liver, 1-[4-(aminocarbonyl)-2-methylphenyl]-5-[4-(1H-imidazol-1-yl)phenyl]-1H-pyrrole-2-propanoic acid (N6022) or N-acetyl-lysyltyrosylcysteine amide (KYC) for three weeks. Human umbilical vein endothelial cells (HUVEC) were treated with recombinant HMGB1 (r-HMGB1), which increases S-nitrosoglutathione reductase (GSNOR) expression by ∼80%, demonstrating a direct effect of HMGB1 to increase GSNOR. Treatment of SS mice with hE-HMGB1-BP reduced plasma HMGB1 in SS mice to control levels and reduced GSNOR expression in facialis arteries isolated from SS mice by ∼20%. These changes were associated with improved endothelial-dependent vasodilation. Treatment of SS mice with N6022 also improved vasodilation in SS mice suggesting that targeting GSNOR also improves vasodilation. SCD decreased protein nitrosothiols (SNOs) and radial alveolar counts (RAC) and increased GSNOR expression and mean linear intercepts (MLI) in lungs from SS mice. The marked changes in pulmonary morphometrics and GSNOR expression throughout the lung parenchyma in SS mice were improved by treating with either hE-HMGB1-BP or KYC. These data demonstrate that murine SCD induces vasculopathy and chronic lung disease by an HMGB1- and GSNOR-dependent mechanism and suggest that HMGB1 and GSNOR might be effective therapeutic targets for reducing vasculopathy and chronic lung disease in humans with SCD.

Efficacies of S-nitrosoglutathione (GSNO) and GSNO reductase inhibitor in SARS-CoV-2 spike protein induced acute lung disease in mice

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which initially surfaced in late 2019, often triggers severe pulmonary complications, encompassing various disease mechanisms such as intense lung inflammation, vascular dysfunction, and pulmonary embolism. Currently, however, there's no drug addressing all these mechanisms simultaneously. This study explored the multi-targeting potential of S-nitrosoglutathione (GSNO) and N6022, an inhibitor of GSNO reductase (GSNOR) on markers of inflammatory, vascular, and thrombotic diseases related to COVID-19-induced acute lung disease. For this, acute lung disease was induced in C57BL/6 mice through intranasal administration of recombinant SARS-CoV-2 spike protein S1 domain (SP-S1). The mice exhibited fever, body weight loss, and increased blood levels and lung expression of proinflammatory cytokines (e.g., TNF-α and IL-6) as well as increased vascular inflammation mediated by ICAM-1 and VCAM-1 and lung infiltration by immune cells (e.g., neutrophils, monocytes, and activated cytotoxic and helper T cells). Further, the mice exhibited increased lung hyperpermeability (lung Evans blue extravasation) leading to lung edema development as well as elevated blood coagulation factors (e.g., fibrinogen, thrombin, activated platelets, and von Willebrand factor) and lung fibrin deposition. Similar to the patients with COVID-19, male mice showed more severe disease than female mice, along with higher GSNOR expression in the lungs. Optimization of GSNO by treatment with exogenous GSNO or inhibition of GSNOR by N6022 (or GSNO knockout) protects against SP-S1-induced lung diseases in both genders. These findings provide evidence for the potential efficacies of GSNO and GSNOR inhibitors in addressing the multi-mechanistic nature of SARS-CoV-2 SP-associated acute-lung disease.

A2AR antagonist treatment for multiple sclerosis: Current progress and future prospects

Emerging evidence suggests that both selective and non-selective Adenosine A2A receptor (A2AR) antagonists could effectively protect mice from experimental autoimmune encephalomyelitis (EAE), which is the most commonly used animal model for multiple sclerosis (MS) research. Meanwhile, the recent FDA approval of Nourianz® (istradefylline) in 2019 as an add-on treatment to levodopa in Parkinson's disease (PD) with "OFF" episodes, along with its proven clinical safety, has prompted us to explore the potential of A2AR antagonists in treating multiple sclerosis (MS) through clinical trials. However, despite promising findings in experimental autoimmune encephalomyelitis (EAE), the complex and contradictory role of A2AR signaling in EAE pathology has raised concerns about the feasibility of using A2AR antagonists as a therapeutic approach for MS. This review addresses the potential effect of A2AR antagonists on EAE/MS in both the peripheral immune system (PIS) and the central nervous system (CNS). In brief, A2AR antagonists had a moderate effect on the proliferation and inflammatory response, while exhibiting a potent anti-inflammatory effect in the CNS through their impact on microglia, astrocytes, and the endothelial cells/epithelium of the blood-brain barrier. Consequently, A2AR signaling remains an essential immunomodulator in EAE/MS, suggesting that A2AR antagonists hold promise as a drug class for treating MS.

Exploring the Role of Neurotransmitters in Multiple Sclerosis: An Expanded Review

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Although emerging evidence has shown that changes in neurotransmitter levels in the synaptic gap may contribute to the pathophysiology of MS, their specific role has not been elucidated yet. In this review, we aim to analyze preclinical and clinical evidence on the structural and functional changes in neurotransmitters in MS and critically discuss their potential role in MS pathophysiology. Preclinical studies have demonstrated that alterations in glutamate metabolism may contribute to MS pathophysiology, by causing excitotoxic neuronal damage. Dysregulated interaction between glutamate and GABA results in synaptic loss. The GABAergic system also plays an important role, by regulating the activity and plasticity of neural networks. Targeting GABAergic/glutamatergic transmission may be effective in fatigue and cognitive impairment in MS. Acetylcholine (ACh) and dopamine can also affect the T-mediated inflammatory responses, thereby being implicated in MS-related neuroinflammation. Also, melatonin might affect the frequency of relapses in MS, by regulating the sleep-wake cycle. Increased levels of nitric oxide in inflammatory lesions of MS patients may be also associated with axonal neuronal degeneration. Therefore, neurotransmitter imbalance may be critically implicated in MS pathophysiology, and future studies are needed for our deeper understanding of their role in MS.

Roles and current applications of S-nitrosoglutathione in anti-infective biomaterials

Bacterial infections can compromise the physical and biological functionalities of humans and pose a huge economical and psychological burden on infected patients. Nitric oxide (NO) is a broad-spectrum antimicrobial agent, whose mechanism of action is not affected by bacterial resistance. S-nitrosoglutathione (GSNO), an endogenous donor and carrier of NO, has gained increasing attention because of its potent antibacterial activity and efficient biocompatibility. Significant breakthroughs have been made in the application of GSNO in biomaterials. This review is based on the existing evidence that comprehensively summarizes the progress of antimicrobial GSNO applications focusing on their anti-infective performance, underlying antibacterial mechanisms, and application in anti-infective biomaterials. We provide an accurate overview of the roles and applications of GSNO in antibacterial biomaterials and shed new light on the avenues for future studies.

Antiperspirant effects and mechanism investigation of Mulisan decoction in rats based on plasma metabolomics

CONTEXT

Mulisan decoction (MLS) is a classic formula of traditional Chinese medicine for treating hyperhidrosis. The mechanism remains unclear.

OBJECTIVE

To investigate the antiperspirant effect and underlying mechanisms of MLS.

MATERIALS AND METHODS

Fifty rats were divided into control, model, and three doses of MLS intervention groups (n = 10). Rats except for control group were induced diseases features of the applicable scope of MLS via i.p. reserpine (0.5 mg/kg/d) for 10 days. From day 11, MLS groups were administrated orally MLS at 0.6, 3, and 15 g/kg once a day for 14 days, respectively. After the last administration, sweating was induced in all rats via s.c. pilocarpine (25 mg/kg), the right hind foot of rats was stained, and sweat point numbers were observed. Rat serum was collected to detect IL-2, IL-6, IFN-γ, and TNF-α. Rat plasma was collected for endogenous metabolite analysis via UPLC-QE-Focus-MS.

RESULTS

Rats treated with MLS presented a significant decrease in sweat point numbers (13.5%), increase in body weight (13.2%), and promotion in the balance of Th1/Th2 cytokine ratio via increasing IL-2 (38.3%), IFN-γ (20.1%), and TNF-α (22.0%) and decreasing IL-6 (24.7%) compared with the model group (p < 0.05). Plasma metabolomics disclosed 15 potential biomarkers related to model rats, of which two could be significantly reversed by MLS (p < 0.05). The involved pathways were pantothenate and CoA biosynthesis, and porphyrin metabolism.

CONCLUSIONS

MLS demonstrated a good antiperspirant effect and metabolism improvement. These findings inspire more clinical study validation on immune improvement and antiperspirant effect.

Novel recombinant protein flagellin A N/C attenuates experimental autoimmune encephalomyelitis by suppressing the ROS/NF-κB/NLRP3 signaling pathway

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease characterized by demyelination and neurodegeneration, for which traditional treatment offers limited relief. Microglial/macrophage modulation plays a critical role in the pathogenesis of MS. Oxygen free radical accumulation can induce axonal and nerve cell damage, and further promote MS development. We created a new recombinant protein based on flagellin from Legionella pneumophila named flagellin A with linked C- and N-terminal ends (FLaAN/C), which is an independent intellectual property of our team. We previously showed that FLaAN/C might mitigate radiation-induced damage by inhibiting inflammatory responses and oxidative stress. However, whether FLaAN/C protects against MS remains unknown. Here, we investigated the anti-inflammatory effects of FLaAN/C on mice with experimental autoimmune encephalomyelitis (EAE) induced by oligodendrocyte glycoprotein peptide 35-55 (MOG35-55). The mice were injected intraperitoneally with FLaAN/C after the onset of clinical symptoms, then clinical behavior scores and changes in body weight were recorded daily. The spinal lumbar spine in model mice was enlarged and accompanied by inflammatory cell infiltration and demyelination that were reversed by FLaAN/C. FLaAN/C also induced microglia/macrophages to generate less pro-inflammatory (CD86, iNOS, and TNF-α), and more anti-inflammatory (CD206, IL-10, and Arginase-1) cytokines. These findings suggesting that FLaAN/C promoted microglial/macrophages polarization from the inflammatory M1 to the anti-inflammatory M2 phenotype. Moreover, FLaAN/C inhibited release of the inflammatory cytokines, TNF-α, IL-8, IL-6, IL-17, and IFN-γ. These results indicated that the anti-inflammatory effect of FLaAN/C was associated with the inhibited generation of reactive oxygen species. FLaAN/C downregulated the expression of phosphorylated NF-κB-p65 and prevented downstream NLRP3 inflammasome-mediated pyroptosis. Collectively, these results indicated that FLaAN/C prevents pyroptosis by inhibiting the ROS/NF-κB/NLRP3 signaling pathway, and promotes the microglial/macrophage M1/M2 polarization that significantly alleviated inflammation in mouse models of EAE. Our findings suggested that FLaAN/C could be a promising candidate for MS therapy.

GSNOR deficiency attenuates MPTP-induced neurotoxicity and autophagy by facilitating CDK5 S-nitrosation in a mouse model of Parkinson's disease

The S-nitrosoglutathione reductase (GSNOR) is a key denitrosating enzyme that regulates protein S-nitrosation, a process which has been found to be involved in the pathogenesis of Parkinson's disease (PD). However, the physiological function of GSNOR in PD remains unknown. In a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model, we found that GSNOR expression was significantly increased and accompanied by autophagy mediated by MPTP-induced cyclin dependent kinase 5 (CDK5), behavioral dyskinesias and dopaminergic neuron loss. Whereas, knockout of GSNOR, or treatment with the GSNOR inhibitor N6022, alleviated MPTP-induced PD-like pathology and neurotoxicity. Mechanistically, deficiency of GSNOR inhibited MPTP-induced CDK5 kinase activity and CDK5-mediated autophagy by increasing S-nitrosation of CDK5 at Cys83. Our study indicated that GSNOR is a key regulator of CDK5 S-nitrosation and is actively involved in CDK5-mediated autophagy induced by MPTP.