NF-kappaB regulates phagocytic NADPH oxidase by inducing the expression of gp91phox

Norepinephrine promotes oxidative stress in vascular adventitial fibroblasts via PKC/NFκB-mediated NOX2 upregulation

BACKGROUND

Sympathetic overactivity is closely associated with vascular remodeling. Sympathetic fibers dominantly innervate the adventitia of arteries rather than tunica media. Vascular adventitial fibroblasts (VAFs) play crucial roles in vascular remodeling. However, the link between sympathetic overactivity and VAF proliferation and migration is unknown.

METHODS

Primary VAFs were isolated from the thoracic aorta of spontaneously hypertensive rats and Wistar-Kyoto rats. Norepinephrine (NE) bitartrate monohydrate was applied to VAFs to simulate the sympathetic overactivity.

RESULTS

NE increased NADPH oxidase (NOX) 2 expression and superoxide level, which were almost abolished by NOX2 inhibitor GSK2795039 or α-adrenoceptor antagonist prazosin, but not significantly affected by NOX1 inhibitor ML171, NOX4 inhibitor GLX351322 or β-adrenoceptor antagonist propranolol. Superoxide scavenger tempol or NOX2 inhibitor GSK2795039 attenuated NE-induced VAF proliferation and migration. NE promoted protein kinase C (PKC) phosphorylation and NFκB-p65 nuclear translocation. Either PKC inhibitor Go6983 or NFκB inhibitor BAY11-7082 attenuated NE-induced NOX activation, NOX2 upregulation, superoxide production, proliferation and migration.

CONCLUSION

NE promotes oxidative stress by α-receptor/PKC/NFκB-mediated NOX2 upregulation, which contributes to proliferation and migration of VAFs.

GFOD1 regulates oxidative stress-induced damage in ADHD via NF-κB signaling pathway

Attention-deficit/hyperactivity disorder (ADHD) is a mental behavioral disorder that poses a serious health risk. Oxidative stress, which damages the function of neurons and astrocytes, has been discovered as a key factor contributing to ADHD pathology. A newly identified gene, Glucose-fructose oxidoreductase domain 1 (GFOD1), may be linked to the development of ADHD. It plays a role in regulating oxidative stress in ADHD; however, its exact role is unclear. This manuscript investigates the changes of GFOD1 expression and aim to correlate this with oxidative stress induced by NF-κB signaling pathway in the rat brains with ADHD and in vitro astrocytes. Our results revealed an increase in GFOD1 expression in the prefrontal cortex and cerebellar cortex of rats with ADHD, accompanied by neuronal injury and increased glial fibrillary acidic protein (GFAP) expression in astrocytes, concomitant with activation of the NF-κB p65/NOX2 signaling pathway. Along with this, GFOD1 overexpression in astrocytes resulted in an up-regulation of this signaling pathway similarly. Both ADHD rats and astrocytes in overexpressing GFOD1 showed elevated levels of reactive oxygen species (ROS) and Malondialdehyde (MDA), reduced activity of superoxide dismutase (SOD). Furthermore, treatment with the methylphenidate (MPH) did not affect GFOD1 expression. But it impacted the levels of oxidative stress mediated by the NF-κB p65/NOX2 signaling pathway. Overall, it is suggested that GFOD1 may contribute to increased levels of oxidative stress specifically in the prefrontal cortex and cerebellar cortex regions and astrocytes affected by ADHD via up-regulation of the NF-κB p65/NOX2/oxidative stress axis.

Exploring potential targets and mechanisms of PCB52-induced cardiotoxicity: Integration of network toxicology and zebrafish experimental evidence

2,2',5,5'-Tetrachlorobiphenyl (PCB52) exhibits high environmental mobility and bioaccumulation potential. Studies have associated elevated levels of serum PCB52 with an increased risk of cardiac diseases, yet the underlying mechanisms of its cardiotoxicity remain inadequately investigated. In this study, potential PCB52 targets and cardiotoxicity-related targets were retrieved from multiple online databases, and 150 potential targets of PCB52-induced cardiotoxicity were obtained. Protein-protein interaction (PPI) network was constructed for the potential targets. Twelve hub genes (STAT1, FN1, TP53, CCL2, ACE, PARP1, NFKB1, MTOR, HDAC2, RELA, ATM, and APP) were identified from the network using 7 algorithms from cytoHubba plugin in Cytoscape. Molecular docking was employed to validate the interactions between PCB52 and hub targets. Enrichment analysis focusing on the hub genes indicated oxidative stress, apoptosis, nuclear factor kappa-B (NF-κB) activation, and inflammatory pathways were primary processes involved. Following exposure to three concentrations of PCB52 (10, 200, and 1000 μg/L), zebrafish exhibited pericardial edema (PE), with the highest incidence of 16.4 % observed at the highest concentration. Additionally, zebrafish experiments revealed a dose-dependent increase in sinus venosus (SV)-bulbus arteriosus (BA) distance and superoxide dismutase (SOD) activity, along with a decrease in heart rate. Furthermore, dose-dependent transcriptomic analyses emphasized the significance of apoptosis and the mitogen-activated protein kinase (MAPK) signaling pathway. Collectively, our study investigated the cardiotoxic effects of PCB52 and proposed a potential toxic mechanism cascade, which warrants further validation through subsequent experiments.

Therapeutic S100A8/A9 inhibition reduces NADPH oxidase expression, reactive oxygen species production and NLRP3 inflammasome priming in the ischemic myocardium

Oxidative stress and alterations in redox signalling have been implicated in the pathophysiology of myocardial infarction (MI). NADPH oxidase (Nox) is an important source of reactive oxygen species (ROS) in the infarcted myocardium. Alarmin S100A8/A9 amplifies acute myocardial inflammation in MI and has been shown to be a promising therapeutic target to improve cardiac function post-MI. We aimed to elucidate the underlying mechanisms linking S100A8/A9, oxidative stress and the inflammatory response in MI. MI was induced by permanent left coronary artery ligation in C57BL/6J mice, followed by treatment with the S100A8/A9 inhibitor ABR-238901 (30 mg/kg) or PBS for 3 days. The in-vivo experiments were complemented with mechanistic studies on cultured macrophages (Mac), important cellular effectors in MI. Compared to sham-operated animals, we detected significant increases in the Nox1, Nox2, Nox4 catalytic subunits at mRNA and protein levels, and NADPH-dependent ROS production in the left ventricle of MI mice. S100A8/A9 blockade prevented the up-regulation of Nox1/2/4 expression, reduced ROS formation, suppressed NF-kB activation and prevented NLRP3 inflammasome priming and activation, leading to reduced levels of active IL-1β. In-vitro, S100A8/A9 induced gene expression of Nox catalytic subtypes and NLRP3 in Mac in a TLR4-dependent and dose-dependent manner. These effects were counteracted by pharmacological inhibition of S100A8/9, TLR4, Nox1/4 and Nox2. In conclusion, we show that Nox upregulation and ROS formation triggered by S100A8/A9 contributes to NLRP3 inflammasome priming and increased IL-1β production in the infarcted myocardium. These mechanisms can be therapeutically targeted to prevent inflammatory and oxidant myocardial damage in acute MI.

Tissue engineering with targeted delivery of nanotized S-nitrosyl mutant of NEMO ameliorates myocardial infarction

BACKGROUND

Myocardial infarction (MI) is characterized by an elevated nitrosative and hypoxic microenvironment due to reduced coronary blood flow. NEMO (IKKγ) regulates the formation of the IKK holo-complex to activate NFκB-p65 signaling. This study reports successful restoration of MI through cardiomyocyte-targeted nanotized S-nitrosyl mutant of NEMO under elevated nitrosative stress.

METHODS

The MI model was generated in male Wistar rats. S-nitrosyl mutant of NEMO (R- NEMO) was selectively delivered to the cardiomyocytes via targeted chitosan nano-vehicle.

RESULTS

Nano-conjugated R- NEMO delivery to diseased cardiomyocytes resulted in downregulation of nitrosative stress and cellular apoptosis leading to regressed infarct area with improved cardiac pathophysiology. Mechanistically, NEMO-p300 binding in R- NEMO expressed cells destabilized p65-p300 complex leading to regressed nitrosative stress and cellular apoptosis. The NEMO mutant inhibits the PGC1α-p65 complex-mediated degradation of PGC1α, leading to upregulation of VEGF. A shift in the binding preference of p65 from PGC1α/p300 to HDAC1 results in the downregulation of the cell-cycle inhibitor and the induction of cell-cycle re-entry markers during MI.

CONCLUSION

Tissue-targeted R- NEMO nanoconjugates show potential to ameliorate MI insult by downregulating apoptosis and promoting the proliferative prowess of the resident cardiomyocytes with potential revascularization at infarct sites; thus, repairing the damaged myocardium.

Friend or foe of tripartite motif-containing protein 21 in cardiovascular disease: A review

As an E3 ubiquitin ligase and an Fc receptor, tripartite motif-containing protein 21 (TRIM21) plays a crucial role in immune defense, signal transduction, and cellular regulation. TRIM21 is widely expressed in various tissues, but it is particularly abundant in cardiovascular tissues and is involved in the pathogenesis of various cardiovascular diseases (CVDs). However, although TRIM21 is involved in the regulation of several key molecular pathways in the immune system, its specific role in CVD remains unclear. In this review, we comprehensively summarize the regulatory role of TRIM21 in signaling pathways and discuss the function of TRIM21 in CVD, to provide a systematic understanding of this important protein in CVD and offer insights for further research into the pathogenesis of CVD and its potential applications.

Major Oxidative and Antioxidant Mechanisms During Heat Stress-Induced Oxidative Stress in Chickens

Heat stress (HS) is one of the most important stressors in chickens, and its adverse effects are primarily caused by disturbing the redox homeostasis. An increase in electron leakage from the mitochondrial electron transport chain is the major source of free radical production under HS, which triggers other enzymatic systems to generate more radicals. As a defense mechanism, cells have enzymatic and non-enzymatic antioxidant systems that work cooperatively against free radicals. The generation of free radicals, particularly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), under HS condition outweighs the cellular antioxidant capacity, resulting in oxidative damage to macromolecules, including lipids, carbohydrates, proteins, and DNA. Understanding these detrimental oxidative processes and protective defense mechanisms is important in developing mitigation strategies against HS. This review summarizes the current understanding of major oxidative and antioxidant systems and their molecular mechanisms in generating or neutralizing the ROS/RNS. Importantly, this review explores the potential mechanisms that lead to the development of oxidative stress in heat-stressed chickens, highlighting their unique behavioral and physiological responses against thermal stress. Further, we summarize the major findings associated with these oxidative and antioxidant mechanisms in chickens.

SET7 lysine methyltransferase mediates the up-regulation of NADPH oxidase expression, oxidative stress, and NLRP3 inflammasome priming in atherosclerosis

BACKGROUND

Dysregulation of histone methylation-based epigenetic mechanisms leads to either transient or long-lasting transcriptomic alterations in vascular and immune cells with important consequences on atherosclerotic plaque development and stability. We hypothesized that the epigenetic enzyme SET7 lysine methyltransferase contributes to the up-regulation of NADPH oxidase (Nox) and NLRP3 inflammasome expression in atherosclerosis.

METHODS

To test this hypothesis, we examined human non-atherosclerotic and atherosclerotic tissue samples, apolipoprotein E-deficient (ApoE-/-) mice, and human macrophages (Mac) employing real-time PCR, Western blot, immunofluorescence microscopy, and histological techniques. Male ApoE-/- mice with established atherosclerosis were randomized to receive concomitant with the high-fat diet, 5 mg/kg (R)-PFI-2, a selective SET7 pharmacological inhibitor, or its vehicle, every other day for 4 weeks.

RESULTS

The results revealed that SET7 mRNA and protein, and H3K4me1 levels were significantly elevated in human carotid atherosclerotic lesions, aorta of atherosclerotic mice, and in cultured pro-inflammatory Mac. In the atherosclerotic mice, pharmacological blockade of SET7 catalytic activity with the specific inhibitor, significantly reduced atherosclerotic plaque development, decreased the aortic up-regulation of mRNA and protein levels of Nox catalytic subunits, mitigated the formation of NT-/4HNE-protein adducts, attenuated NLRP3 gene and protein expression, and reduced pro-caspase-1 and pro-IL18 cleavage. In polarized pro-inflammatory human M1-Mac, SET7-oriented pharmacological intervention reduced the transcriptional up-regulation of Nox catalytic subunits, NLRP3, caspase-1, IL1β, and IL18, and the secretion IL1β and TNFα. Transient overexpression of SET7 in human endothelial cells enhanced mRNA levels of Nox1, Nox2, Nox4, Nox5, and p22phox.

CONCLUSION

The novel results show that SET7 regulates important mechanisms leading to enhanced formation of reactive oxygen species and pro-inflammatory cytokines release in atherosclerosis. The data recommend SET7 as a promising target for pharmacological interventions and as supportive therapeutic strategy in atherosclerotic cardiovascular diseases.

The Dual Role of Oxidative Stress in Atherosclerosis and Coronary Artery Disease: Pathological Mechanisms and Diagnostic Potential

Oxidative stress plays a pivotal role in the pathogenesis of atherosclerosis and coronary artery disease (CAD), with both beneficial and detrimental effects on cardiovascular health. On one hand, the excessive production of reactive oxygen species (ROS) contributes to endothelial dysfunction, inflammation, and vascular remodeling, which are central to the development and progression of CAD. These pathological effects drive key processes such as atherosclerosis, plaque formation, and thrombosis. On the other hand, moderate levels of oxidative stress can have beneficial effects on cardiovascular health. These include regulating vascular tone by promoting blood vessel dilation, supporting endothelial function through nitric oxide production, and enhancing the immune response to prevent infections. Additionally, oxidative stress can stimulate cellular adaptation to stress, promote cell survival, and encourage angiogenesis, which helps form new blood vessels to improve blood flow. Oxidative stress also holds promise as a source of biomarkers that could aid in the diagnosis, prognosis, and monitoring of CAD. Specific oxidative markers, such as malondialdehyde (MDA), isoprostanes (isoP), ischemia-modified albumin, and antioxidant enzyme activity, have been identified as potential indicators of disease severity and therapeutic response. This review explores the dual nature of oxidative stress in atherosclerosis and CAD, examining its mechanisms in disease pathogenesis as well as its emerging role in clinical diagnostics and targeted therapies. The future directions for research aimed at harnessing the diagnostic and therapeutic potential of oxidative stress biomarkers are also discussed. Understanding the balance between the detrimental and beneficial effects of oxidative stress could lead to innovative approaches in the prevention and management of CAD.

Do Lifestyle Interventions Mitigate the Oxidative Damage and Inflammation Induced by Obesity in the Testis?

Obesity results from a disproportionate accumulation of fat and has become a global health concern. The increase in adipose tissue is responsible for several systemic and testicular changes including hormone levels (leptin, adiponectin, testosterone, estrogen), inflammatory cytokines (increase in TNF-α and IL-6 and decrease in IL-10), and redox state (increase in reactive oxygen species and reduction in antioxidant enzymes). This results in poor sperm quality and compromised fertility in men with obesity. Lifestyle modifications, particularly diet transition to caloric restriction and physical exercise, are reported to reverse these negative effects. Nevertheless, precise mechanisms mediating these benefits, including how they modulate testicular oxidative stress, inflammation, and metabolism, remain to be fully elucidated. The main pathway described by which these lifestyle interventions reverse obesity-induced oxidative damage is the Nrf2-SIRT1 axis, which modulates the overexpression of antioxidant defenses. Of note, some of the detrimental effects of obesity on the testis are inherited by the descendants of individuals with obesity, and while caloric restriction reverses some of these effects, no significant work has been carried out regarding physical exercise. This review discusses the consequences of obesity-induced testicular oxidative stress on adult and pediatric populations, emphasizing the therapeutic potential of lifestyle to mitigate these detrimental effects.

Flavins and Flavoproteins in the Neuroimmune Landscape of Stress Sensitization and Major Depressive Disorder

Major Depressive Disorder (MDD) is a common and severe neuropsychiatric condition resulting in irregular alterations in affect, mood, and cognition. Besides the well-studied neurotransmission-related etiologies of MDD, several biological systems and phenomena, such as the hypothalamic-pituitary-adrenal (HPA) axis, reactive oxygen species (ROS) production, and cytokine signaling, have been implicated as being altered and contributing to depressive symptoms. However, the manner in which these factors interact with each other to induce their effects on MDD development has been less clear, but is beginning to be understood. Flavins are potent biomolecules that regulate many redox activities, including ROS generation and energy production. Studies have found that circulating flavin levels are modulated during stress and MDD. Flavins are also known for their importance in immune responses. This review offers a unique perspective that considers the redox-active cofactors, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), as vital substrates for linking MDD-related maladaptive processes together, by permitting stress-induced enhancement of microglial interleukin-1 beta (IL-1β) signaling.

Drugs repurposing in the experimental models of Alzheimer's disease

The currently approved drugs for Alzheimer's disease (AD) are only for symptomatic treatment in the early stages of the disease but they could not halt the neurodegeneration, additionally, the safety profile of the recently developed immunotherapy is a big issue. This review aims to explain the importance of the drugs repurposing technique and strategy to develop therapy for AD. We illustrated the biological alterations in the pathophysiology of AD including the amyloid pathology, the Tau pathology, oxidative stress, mitochondrial dysfunction, neuroinflammation, glutamate-mediated excitotoxicity, insulin signaling impairment, wingless-related integration site/β-catenin signaling, and autophagy. Additionally, we demonstrated the different repurposed drugs in the experimental models of AD including the anti-inflammatory, anti-hypertensive, anti-diabetic, antiepileptic, antidepressant and anticancer drugs. Further, we showed the pipeline and FDA approved drugs for AD. The repurposed drugs have a promising therapeutic activity against AD, confirming the value of the drugs repurposing technique to elucidate curative therapy for AD.

Navigating the redox landscape: reactive oxygen species in regulation of cell cycle

Objectives: To advance our knowledge of disease mechanisms and therapeutic options, understanding cell cycle regulation is critical. Recent research has highlighted the importance of reactive oxygen species (ROS) in cell cycle regulation. Although excessive ROS levels can lead to age-related pathologies, ROS also play an essential role in normal cellular functions. Many cell cycle regulatory proteins are affected by their redox status, but the precise mechanisms and conditions under which ROS promote or inhibit cell proliferation are not fully understood.Methods: This review presents data from the scientific literature and publicly available databases on changes in redox state during the cell cycle and their effects on key regulatory proteins.Results: We identified redox-sensitive targets within the cell cycle machinery and analysed different effects of ROS (type, concentration, duration of exposure) on cell cycle phases. For example, moderate levels of ROS can promote cell proliferation by activating signalling pathways involved in cell cycle progression, whereas excessive ROS levels can induce DNA damage and trigger cell cycle arrest or cell death.Discussion: Our findings encourage future research focused on identifying redox-sensitive targets in the cell cycle machinery, potentially leading to new treatments for diseases with dysregulated cell proliferation.

CB1 Receptor Activation Provides Neuroprotection in an Animal Model of Glutamate-Induced Excitotoxicity Through a Reduction of NOX-2 Activity and Oxidative Stress

BACKGROUND

Excitotoxicity is a process in which NADPH oxidase-2 (NOX-2) plays a pivotal role in the generation of reactive oxygen species (ROS). Oxidative stress influences the expression of Aquaporin 4 (AQP4), a water channel implicated in blood-brain barrier (BBB) permeability and edema formation. The endocannabinoid system is widely distributed in the brain, particularly through the cannabinoid receptor type 1 (CB1) and type 2 (CB2), which have been shown to have a neuroprotective function in brain injury. Given the significant involvement of NOX-2 in ROS production during excitotoxicity, our research aims to assess the participation of NOX-2 in the neuroprotective effect of the cannabinoid receptor agonist WIN55,212-2 against glutamate-induced excitotoxicity damage in the striatum using in vivo model.

METHODS

Wild-type mice (C57BL/6) and NOX-2 KO (gp91Cybbtm1Din/J) were stereotactically injected in the striatum with monosodium glutamate or vehicle. Subsequently, a group of mice was administered an intraperitoneal dose of WIN55,212-2, AM251, or AM251/WIN55,212-2 following the intracerebral injection. Motor activity was assessed, and the lesion was examined through histological sections stained with cresyl violet. Additionally, brain water content and Evans blue assay were conducted. The activity of NOX was quantified, and the protein expression of CB1, gp91phox, AQP4, Iba-1, TNF-α, and NF-κB was analyzed using Western blot. Furthermore, ROS formation was measured through the DHE assay.

RESULTS

The activation of the endocannabinoid receptors demonstrated a neuroprotective response during excitotoxicity, meditated by NOX-2. The reduction in ROS production led to a decrease in neuroinflammation, and AQP4 expression, resulting in reduced edema formation, and BBB permeability.

CONCLUSIONS

During excitotoxic damage, WIN55,212-2 inhibits NOX-2-induced ROS production, reducing brain injury.

TRPM2 channels are essential for regulation of cytokine production in lung interstitial macrophages

Interstitial macrophages (IMs) are essential for organ homeostasis, inflammation, and autonomous immune response in lung tissues, which are achieved through polarization to a pro-inflammatory M1 and an M2 state for tissue repair. Their remote parenchymal localization and low counts, however, are limiting factors for their isolation and molecular characterization of their specific role during tissue inflammation. We isolated viable murine IMs in sufficient quantities by coculturing them with stromal cells and analyzed mRNA expression patterns of transient receptor potential (TRP) channels in naïve and M1 polarized IMs after application of lipopolysaccharide (LPS) and interferon γ. M-RNAs for the second member of the melastatin family of TRP channels, TRPM2, were upregulated in the M1 state and functional channels were identified by their characteristic currents induced by ADP-ribose, its specific activator. Most interestingly, cytokine production and secretion of interleukin-1α (IL-1α), IL-6 and tumor necrosis factor-α in M1 polarized but TRPM2-deficient IMs was significantly enhanced compared to WT cells. Activation of TRPM2 channels by ADP-ribose (ADPR) released from mitochondria by ROS-produced H2O2 significantly increases plasma membrane depolarization, which inhibits production of reactive oxygen species by NADPH oxidases and reduces cytokine production and secretion in a negative feedback loop. Therefore, TRPM2 channels are essential for the regulation of cytokine production in M1-polarized murine IMs. Specific activation of these channels may promote an anti-inflammatory phenotype and prevent a harmful cytokine storm often observed in COVID-19 patients.

Psilocin, the Psychoactive Metabolite of Psilocybin, Modulates Select Neuroimmune Functions of Microglial Cells in a 5-HT2 Receptor-Dependent Manner

Neuroinflammation that is caused by microglia, the main immune cells of the brain, contributes to neurodegenerative diseases. Psychedelics, including psilocybin and lysergic acid diethylamide (LSD), possess certain anti-inflammatory properties and, therefore, should be considered as drug candidates for treating neuroinflammatory pathologies. When ingested, psilocybin is rapidly dephosphorylated to yield psilocin, which crosses the blood-brain barrier and exerts psychotropic activity by interacting with the 5-hydroxytryptamine 2A receptors (5-HT2ARs) on neurons. Since microglia express all three 5-HT2R isoforms, we hypothesized that, by interacting with these receptors, psilocin beneficially modulates select neuroimmune functions of microglia. We used microglia-like cell lines to demonstrate that psilocin, at non-toxic concentrations, did not affect the secretion of tumor necrosis factor (TNF) by immune-stimulated microglial cells, but significantly inhibited their phagocytic activity, the release of reactive oxygen species (ROS), and nitric oxide (NO) production. The inhibitory activity of psilocin on the latter two functions was similar to that of two selective 5-HT2R agonists, namely, 25I-NBOH and Ro60-0175. The role of this subfamily of receptors was further demonstrated by the application of 5-HT2R antagonists cyproheptadine and risperidone. Psilocin should be considered a novel drug candidate that might be effective in treating neuroimmune disorders, such as neurodegenerative diseases, where reactive microglia are significant contributors.

The Role of Oxidative Stress in Hypomagnetic Field Effects

The geomagnetic field (GMF) is crucial for the survival and evolution of life on Earth. The weakening of the GMF, known as the hypomagnetic field (HMF), significantly affects various aspects of life on Earth. HMF has become a potential health risk for future deep space exploration. Oxidative stress is directly involved in the biological effects of HMF on animals or cells. Oxidative stress occurs when there is an imbalance favoring oxidants over antioxidants, resulting in cellular damage. Oxidative stress is a double-edged sword, depending on the degree of deviation from homeostasis. In this review, we summarize the important experimental findings from animal and cell studies on HMF exposure affecting intracellular reactive oxygen species (ROS), as well as the accompanying many physiological abnormalities, such as cognitive dysfunction, the imbalance of gut microbiota homeostasis, mood disorders, and osteoporosis. We discuss new insights into the molecular mechanisms underlying these HMF effects in the context of the signaling pathways related to ROS. Among them, mitochondria are considered to be the main organelles that respond to HMF-induced stress by regulating metabolism and ROS production in cells. In order to unravel the molecular mechanisms of HMF action, future studies need to consider the upstream and downstream pathways associated with ROS.

Resolvin D5 Protects Female Hairless Mouse Skin from Pathological Alterations Caused by UVB Irradiation

Resolvin D5 (RvD5) is a lipid mediator that has been reported to present anti-inflammatory and pro-resolution properties. Evidence also supports its capability to enhance reactive oxygen species (ROS) production during bacterial infections, which would be detrimental in diseases driven by ROS. The biological activity of RvD5 and mechanisms against UVB irradiation skin pathology have not been investigated so far. Female hairless mice were treated intraperitoneally with RvD5 before UVB stimulus. RvD5 reduced skin edema in a dose-dependent manner as well as oxidative stress by increasing antioxidants (endogenous tissue antioxidant scavenging of cationic radical, iron reduction, catalase activity and reduced glutathione levels) and decreasing pro-oxidants (superoxide anion and lipid peroxidation). RvD5 antioxidant activity was accompanied by enhancement of Nrf2, HO-1 and NQO1 mRNA expression. RvD5 reduced the production of IL-1β, TNF-α, TGF-β, and IL-10. RvD5 also reduced the inflammatory cell counts, including mast cells and neutrophils/macrophages. The reduction of oxidative stress and inflammation resulted in diminished matrix metalloproteinase 9 activity, collagen degradation, epidermal thickening and sunburn cell development. Therefore, this study demonstrates, to our knowledge, the first body of evidence that RvD5 can be used to treat UVB skin pathology and unveils, at least in part, its mechanisms of action.

Redox regulation of macrophages

Redox signaling, a mode of signal transduction that involves the transfer of electrons from a nucleophilic to electrophilic molecule, has emerged as an essential regulator of inflammatory macrophages. Redox reactions are driven by reactive oxygen/nitrogen species (ROS and RNS) and redox-sensitive metabolites such as fumarate and itaconate, which can post-translationally modify specific cysteine residues in target proteins. In the past decade our understanding of how ROS, RNS, and redox-sensitive metabolites control macrophage function has expanded dramatically. In this review, we discuss the latest evidence of how ROS, RNS, and metabolites regulate macrophage function and how this is dysregulated with disease. We highlight the key tools to assess redox signaling and important questions that remain.

Increased stress vulnerability in the offspring of socially isolated rats: Behavioural, neurochemical and redox dysfunctions

Stressful events during pregnancy impact on the progeny neurodevelopment. However, little is known about preconceptional stress effects. The rat social isolation represents an animal model of chronic stress inducing a variety of dysfunctions. Moreover, social deprivation during adolescence interferes with key neurodevelopmental processes. Here, we investigated the development of behavioural, neurochemical and redox alterations in the male offspring of socially isolated female rats before pregnancy, reared in group (GRP) or in social isolation (ISO) from weaning until young-adulthood. To this aim, females were reared in GRP or in ISO conditions, from PND21 to PND70, when they were mated. Their male offspring was housed in GRP or ISO conditions through adolescence and until PND70, when passive avoidance-PA, novel object recognition-NOR and open field-OF tests were performed. Levels of noradrenaline (NA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), glutamate (GLU) and GABA were assessed in the prefrontal cortex (PFC). Moreover, cortical ROS levels were quantified, as well as NF-kB and the NADPH oxidase NOX2 expression, redox status (expressed as GSH:GSSG ratio) and SOD1 amount. A significant decrease of the latency time in the PA was observed in the offspring of ISO females. In the NOR test, while a significant increase in the exploratory activity towards the novel object was observed in the offspring of GRP females, no significant differences were found in the offspring of ISO females. No significant differences were found in the OF test among experimental groups. Theoffspring of ISO females showed increased NA and 5-HIAA levels, whereas in the offspring persistently housed in isolation condition from weaninguntil adulthood, we detected reduced 5-HT levels and ehnanced 5-HIAA amount. No significant changes in GLU concentrations were detected, while decreased GABA content was observed in the offspring of ISO females exposed to social isolation. Increased ROS levels as well as reduced NF-κB, NOX2 expression were detected in the offspring of ISO females. This was accompanied by reduced redox status and enhanced SOD1 levels. In conclusion, our results suggest that female exposure to chronic social stress before pregnancy might have a profound influence on the offspring neurodevelopment in terms of cognitive, neurochemical and redox-related alterations, identifying this specific time window for possible preventive and therapeutic strategies.

SIRT1 and thrombosis

Thrombosis is a major cause of morbidity and mortality worldwide, with a complex and multifactorial pathogenesis. Recent studies have shown that SIRT1, a member of the sirtuin family of NAD + -dependent deacetylases, plays a crucial role in regulating thrombosis, modulating key pathways including endothelial activation, platelet aggregation, and coagulation. Furthermore, SIRT1 displays anti-inflammatory activity both in vitro, in vivo and in clinical studies, particularly via the reduction of oxidative stress. On these bases, several studies have investigated the therapeutic potential of targeting SIRT1 for the prevention of thrombosis. This review provides a comprehensive and critical overview of the main preclinical and clinical studies and of the current understanding of the role of SIRT1 in thrombosis.

Porcine Placenta Peptide Inhibits UVB-Induced Skin Wrinkle Formation and Dehydration: Insights into MAPK Signaling Pathways from In Vitro and In Vivo Studies

Excessive exposure to ultraviolet (UV) radiation from sunlight accelerates skin aging, leading to various clinical manifestations such as wrinkles, dryness, and loss of elasticity. This study investigated the protective effects of porcine placenta peptide (PPP) against UVB-induced skin photoaging. Female hairless SKH-1 mice were orally administered PPP for 12 weeks, followed by UVB irradiation. PPP significantly reduced wrinkle formation, improved skin moisture levels, and prevented collagen degradation. Mechanistically, PPP inhibited the expression of matrix metalloproteinases (MMPs) and upregulated collagen production. Moreover, PPP elevated hyaluronic acid levels, contributing to enhanced skin hydration. Additionally, PPP demonstrated antioxidant properties by increasing the expression of the antioxidant enzyme GPx-1, thereby reducing UVB-induced inflammation. Further molecular analysis revealed that PPP suppressed the activation of p38 MAP kinase and JNK signaling pathways, crucial mediators of UV-induced skin damage. These findings highlight the potential of porcine placental peptides as a natural and effective intervention against UVB-induced skin photoaging. The study provides valuable insights into the mechanisms underlying the protective effects of PPP, emphasizing its potential applications in skincare and anti-aging formulations.

Exogenous L-Alanine promotes phagocytosis of multidrug-resistant bacterial pathogens

Multidrug-resistant bacteria present a major threat to public health that urgently requires new drugs or treatment approaches. Here, we conduct integrated proteomic and metabolomics analyses to screen for molecular candidates improving survival of mice infected with Vibrio parahaemolyticus, which indicate that L-Alanine metabolism and phagocytosis are strongly correlated with mouse survival. We also assess the role of L-Alanine in improving mouse survival by in vivo bacterial challenge experiments using various bacteria species, including V. parahaemolyticus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Functional studies demonstrate that exogenous L-Alanine promotes phagocytosis of these multidrug-resistant pathogen species. We reveal that the underlying mechanism involves two events boosted by L-Alanine: TLR4 expression and L-Alanine-enhanced TLR4 signaling via increased biosynthesis and secretion of fatty acids, including palmitate. Palmitate enhances binding of lipopolysaccharide to TLR4, thereby promoting TLR4 dimer formation and endocytosis for subsequent activation of the PI3K/Akt and NF-κB pathways and bacteria phagocytosis. Our data suggest that modulation of the metabolic environment is a plausible approach for combating multidrug-resistant bacteria infection.

Oral delivery of nerolidol alleviates cyclophosphamide-induced renal inflammation, apoptosis, and fibrosis via modulation of NF-κB/cleaved caspase-3/TGF-β signaling molecules

Cyclophosphamide (CP) is one of the most extensively used antineoplastic drug, but the nephrotoxicity caused by this drug is a major limiting factor for its use. Nerolidol (NERO) is a natural bioactive compound with diverse pharmacological actions. In Vitro and in vivo study was performed using HK-2 renal cells and Swiss Albino mice. Cell lines and animals were treated with NERO 25 and 50 µM + 30 µM CP (in vitro), 200 and 400 mg/kg, p.o. NERO from day 1 to day 15 + 200 mg/kg, i.p. CP on day 17 as single intraperitoneal injection (in vivo). The makers of oxidative stress, renal-specific injury markers, inflammation, apoptosis, fibrosis, and histopathological changes were studied. The study's outcome showed a significant reduction in the level of malonaldehyde and interleukin-6 (p < 0.01), tumor necrosis factor-α, IL-1β (p < 0.001), and an increase in the superoxide dismutase, catalase, glutathione and interleukin-10 level (p < 0.01), in the in vivo study when treated with NERO 400 and compared with CP 200. In Vitro study showed reduced expression of nuclear factor kappa light chain enhancer of activated B cells, cleaved caspase-3, kidney injury molecule-1 and transforming growth factor-β-1 (p < 0.001), when treated with NERO 50 µM whereas NERO 25 µM only reduced the level of cleaved caspase-3 (p < 0.05) when compared with 30 µM. NERO 400 also reduced uric acid (p < 0.05), urea (p < 0.01), blood urea nitrogen, and serum creatinine levels (p < 0.001) and increased the level of blood-urea-nitrogen/creatinine ratio (p < 0.001). Additionally, the level of fibrosis-specific markers such as transforming growth factor-β1, hyaluronic acid (p < 0.01), 4-hydroxyproline, a collagen-rich area in Masson's' trichome stain, and Smad3 expression was also significantly reduced (p < 0.001). Furthermore, the outcome of multiple renal staining showed structural reversal aberrations, reduction of the thick basement membrane, and glycogen level toward normal when treated with NERO 400. Thus, the study showed a novel mechanistic modality of NERO against cyclophosphamide-induced renal toxicity. The outcome of this study can be considered a step closer to the development of an adjuvant to mitigate cyclophosphamide-induced renal toxicity among patients treated with cyclophosphamide.

Connection between oxidative stress and subcellular organelle in subarachnoid hemorrhage: Novel mechanisms and therapeutic implications

Spontaneous subarachnoid hemorrhage (SAH) is one of the most devastating forms of stroke, with limited treatment modalities and poor patient outcomes. Previous studies have proposed multiple prognostic factors; however, relative research on treatment has not yet yielded favorable clinical outcomes. Moreover, recent studies have suggested that early brain injury (EBI) occurring within 72 h after SAH may contribute to its poor clinical outcomes. Oxidative stress is recognized as one of the main mechanisms of EBI, which causes damage to various subcellular organelles, including the mitochondria, nucleus, endoplasmic reticulum (ER), and lysosomes. This could lead to significant impairment of numerous cellular functions, such as energy supply, protein synthesis, and autophagy, which may directly contribute to the development of EBI and poor long-term prognostic outcomes. In this review, the mechanisms underlying the connection between oxidative stress and subcellular organelles after SAH are discussed, and promising therapeutic options based on these mechanisms are summarized.

Crebanine ameliorates ischemia-reperfusion brain damage by inhibiting oxidative stress and neuroinflammation mediated by NADPH oxidase 2 in microglia

BACKGROUND

The urgent challenge for ischemic stroke treatment is the lack of effective neuroprotectants that target multiple pathological processes. Crebanine, an isoquinoline-like alkaloid with superior pharmacological activities, presents itself as a promising candidate for neuroprotection. However, its effects and mechanisms on ischemic stroke remain unknown.

METHODS

The effects of crebanine on brain damage following ischemic stroke were evaluated using the middle cerebral artery occlusion and reperfusion (MCAO/R) model. Mechanism of action was investigated using both MCAO/R rats and lipopolysaccharide (LPS)-activated BV-2 cells.

RESULTS

We initially demonstrated that crebanine effectively ameliorated the neurological deficits in MCAO/R rats, while also reducing brain edema and infarction. Treatment with crebanine resulted in the up-regulation of NeuN+ fluorescence density and down-regulation of FJB+ cell count, and mitigated synaptic damage. Crebanine attenuated the hyperactivation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) by downregulating NADP+ and NADPH levels, suppressing gp91phox and p47phox expressions, and reducing p47phox membrane translocation in Iba-1+ cells. Additionally, crebanine reduced the quantity of Iba-1+ cells and protein expression. Correlation analysis has demonstrated that the inhibition of NOX2 activation in microglia is beneficial for mitigating I/R brain injuries. Moreover, crebanine exhibited significant antioxidant properties by down-regulating the expression of superoxide anion and intracellular reactive oxygen species in vivo and in vitro, and reducing lipid and DNA peroxidation. Crebanine exerted anti-inflammatory effect, as evidenced by the reduction in the expressions of nitric oxide, interleukin 1β, tumor necrosis factor α, interleukin 6, and inducible nitric oxide synthase. The effect of crebanine was achieved through the suppression of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathway. This is supported by evidence showing reduced NF-κB p65 promoter activity and nucleus translocation, as well as suppressed IκBα phosphorylation and degradation. Additionally, it inhibited the phosphorylation of ERK, JNK, and p38 MAPKs. Importantly, the anti-oxidative stress and neuroinflammation effects of crebanine were further enhanced after silencing gp91phox and p47phox.

CONCLUSION

Crebanine alleviated the brain damages of MCAO/R rats by inhibiting oxidative stress and neuroinflammation mediated by NOX2 in microglia, implying crebanine might be a potential natural drug for the treatment of cerebral ischemia.

Chronic SIRT1 supplementation in diabetic mice improves endothelial function by suppressing oxidative stress

AIMS

Enhancing SIRT1 activity exerts beneficial cardiovascular effects. In diabetes, plasma SIRT1 levels are reduced. We aimed to investigate the therapeutic potential of chronic recombinant murine SIRT1 (rmSIRT1) supplementation to alleviate endothelial and vascular dysfunction in diabetic mice (db/db).

METHODS AND RESULTS

Left internal mammary arteries obtained from patients undergoing coronary artery bypass grafting with or without a diagnosis of diabetes were assayed for SIRT1 protein levels. Twelve-week-old male db/db mice and db/+ controls were treated with vehicle or rmSIRT1 intraperitoneally for 4 weeks, after which carotid artery pulse wave velocity (PWV) and energy expenditure/activity were assessed by ultrasound and metabolic cages, respectively. Aorta, carotid, and mesenteric arteries were isolated to determine endothelial and vascular function using the myograph system.Arteries obtained from diabetic patients had significantly lower levels of SIRT1 relative to non-diabetics. In line, aortic SIRT1 levels were reduced in db/db mice compared to db/+ mice, while rmSIRT1 supplementation restored SIRT1 levels. Mice receiving rmSIRT1 supplementation displayed increased physical activity and improved vascular compliance as reflected by reduced PWV and attenuated collagen deposition. Aorta of rmSIRT1-treated mice exhibited increased endothelial nitric oxide (eNOS) activity, while endothelium-dependent contractions of their carotid arteries were significantly decreased, with mesenteric resistance arteries showing preserved hyperpolarization. Ex vivo incubation with reactive oxygen species (ROS) scavenger Tiron and NADPH oxidase inhibitor apocynin revealed that rmSIRT1 leads to preserved vascular function by suppressing NADPH oxidase (NOX)-related ROS synthesis. Chronic rmSIRT1 treatment resulted in reduced expression of both NOX1 and NOX4, in line with a reduction in aortic protein carbonylation and plasma nitrotyrosine levels.

CONCLUSIONS

In diabetic conditions, arterial SIRT1 levels are significantly reduced. Chronic rmSIRT1 supplementation improves endothelial function and vascular compliance by enhancing eNOS activity and suppressing NOX-related oxidative stress. Thus, SIRT1 supplementation may represent novel therapeutic strategy to prevent diabetic vascular disease.

Anti-proliferative effect of Cannabidiol in Prostate cancer cell PC3 is mediated by apoptotic cell death, NFκB activation, increased oxidative stress, and lower reduced glutathione status

Prostate cancer is the second most frequent cancer diagnosed in men in the world today. Almost all prostate cancers are adenocarcinomas and develop from gland cells. We used the PC3 prostate cancer cell line, which is well studied and derived from a bone metastasis of a grade IV prostatic adenocarcinoma. Cannabidiol (CBD), a major non-psychoactive constituent of cannabis, is a cannabinoid with anti-tumor properties but its effects on prostate cancer cells are not studied in detail. Here, we found cannabidiol decreased prostate cancer cell (PC3) viability up to 37.25% and induced apoptotic cell death in a time and dose-dependent manner. We found that CBD activated the caspases 3/7 pathways and increased DNA fragmentation. Furthermore, we observed an increase of pro-apoptotic genes Bax, an increased level of reactive oxygen species, lower reduced glutathione level, and altered mitochondrial potential in response to CBD treatment leading to lower cellular ATP. Overall, our results suggest that CBD may be effective against prostate cancer cells.

Isoamericanin A improves lipopolysaccharide-induced memory impairment in mice through suppression of the nicotinamide adenine dinucleotide phosphateoxidase-dependent nuclear factor kappa B signaling pathway

Alzheimer's disease (AD) is the most frequent cause of dementia in the elderly. Isoamericanin A (ISOA) is a natural lignan possessing great potential for AD treatment. This study investigated the efficacy of ISOA on memory impairments in the mice intrahippocampal injected with lipopolysaccharide (LPS) and the underlying mechanism. Y-maze and Morris Water Maze data suggested that ISOA (5 and 10 mg/kg) ameliorated short- and long-term memory impairments, and attenuated neuronal loss and lactate dehydrogenase activity. ISOA exerted anti-inflammatory effect demonstrating by the reduction of ionized calcium-binding adapter molecule 1 positive cells and suppression of marker protein and pro-inflammation cytokines expressions induced by LPS. ISOA suppressed the nuclear factor kappa B (NF-κB) signaling pathway by inhibiting IκBα phosphorylation and NF-κB p65 phosphorylation and nuclear translocation. ISOA inhibited superoxide and intracellular reactive oxygen species accumulation by reducing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, demonstrating by suppressing NADP+ and NADPH contents, gp91phox expression, and p47phox expression and membrane translocation. These effects were enhanced in combination with NADPH oxidase inhibitor apocynin. The neuroprotective effect of ISOA was further proved in the in vitro models. Overall, our data revealed a novel pharmacological activity of ISOA: ameliorating memory impairment in AD via inhibiting neuroinflammation.

Therapeutic potential of NOX inhibitors in neuropsychiatric disorders

RATIONALE

Neuropsychiatric disorders encompass a broad category of medical conditions that include both neurology as well as psychiatry such as major depressive disorder, autism spectrum disorder, bipolar disorder, schizophrenia as well as psychosis.

OBJECTIVE

NADPH-oxidase (NOX), which is the free radical generator, plays a substantial part in oxidative stress in neuropsychiatric disorders. It is thought that elevated oxidative stress as well as neuroinflammation plays a part in the emergence of neuropsychiatric disorders. Including two linked with membranes and four with subunits of cytosol, NOX is a complex of multiple subunits. NOX has been linked to a significant source of reactive oxygen species in the brain. NOX has been shown to control memory processing and neural signaling. However, excessive NOX production has been linked to cardiovascular disorders, CNS degeneration, and neurotoxicity. The increase in NOX leads to the progression of neuropsychiatric disorders.

RESULT

Our review mainly emphasized the characteristics of NOX and its various mechanisms, the modulation of NOX in various neuropsychiatric disorders, and various studies supporting the fact that NOX might be the potential therapeutic target for neuropsychiatric disorders.

CONCLUSION

Here, we summarizes various pharmacological studies involving NOX inhibitors in neuropsychiatric disorders.

Interplay between Systemic Glycemia and Neuroprotective Activity of Resveratrol in Modulating Astrocyte SIRT1 Response to Neuroinflammation

The flow of substances between the blood and the central nervous system is precisely regulated by the blood-brain barrier (BBB). Its disruption due to unbalanced blood glucose levels (hyper- and hypoglycemia) occurring in metabolic disorders, such as type 2 diabetes, can lead to neuroinflammation, and increase the risk of developing neurodegenerative diseases. One of the most studied natural anti-diabetic, anti-inflammatory, and neuroprotective compounds is resveratrol (RSV). It activates sirtuin 1 (SIRT1), a key metabolism regulator dependent on cell energy status. The aim of this study was to assess the astrocyte SIRT1 response to neuroinflammation and subsequent RSV treatment, depending on systemic glycemia. For this purpose, we used an optimized in vitro model of the BBB consisting of endothelial cells and astrocytes, representing microvascular and brain compartments (MC and BC), in different glycemic backgrounds. Astrocyte-secreted SIRT1 reached the highest concentration in hypo-, the lowest in normo-, and the lowest in hyperglycemic backgrounds. Lipopolysaccharide (LPS)-induced neuroinflammation caused a substantial decrease in SIRT1 in all glycemic backgrounds, as observed earliest in hyperglycemia. RSV partially counterbalanced the effect of LPS on SIRT1 secretion, most remarkably in normoglycemia. Our results suggest that abnormal glycemic states have a worse prognosis for RSV-therapy effectiveness compared to normoglycemia.

Inflammation and Neutrophil Oxidative Burst in a Family with NFKB1 p.R157X LOF and Sterile Necrotizing Fasciitis

Loss-of-function (LOF) mutations in NFKB1, coding for p105, may cause common variable immunodeficiency due to dysregulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κΒ) pathway. Monoallelic LOF variants of NFKB1 can predispose to uncontrolled inflammation including sterile necrotizing fasciitis or pyoderma gangrenosum. In this study, we explored the impact of a heterozygous NFKB1 c.C936T/p.R157X LOF variant on immunity in sterile fasciitis patients and their family members. The p50 or p105 protein levels were reduced in all variant carriers. Interleukin-1β (IL-1β) and interleukin-8 (IL-8) levels were elevated in vitro, potentially contributing to the very high neutrophil counts observed during fasciitis episodes. Phosphorylation of p65/RelA was reduced in p.R157X neutrophils suggesting defective activation of canonical NF-κB. Oxidative burst after NF-κB-independent phorbol 12-myristate 13-acetate (PMA) stimulation was similar in both p.R157X and control neutrophils. Comparable amounts of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex subunits were found in p.R157X and control neutrophils. However, a compromised oxidative burst was observed in p.R157X neutrophils following activation of NF-κB-dependent mechanisms following stimulation of toll-like receptor 2 (TLR2) and Dectin-1. Neutrophil extracellular trap formation was not affected by p.R157X. In summary, the NFKB1 c.C936T/p.R157X LOF variant has an impact on inflammation and neutrophil function and may play a role in the pathogenesis of sterile necrotizing fasciitis.

Roles of Oxidative Stress and Nrf2 Signaling in Pathogenic and Non-Pathogenic Cells: A Possible General Mechanism of Resistance to Therapy

The coordinating role of nuclear factor erythroid-2-related factor 2 (Nrf2) in cellular function is undeniable. Evidence indicates that this transcription factor exerts massive regulatory functions in multiple signaling pathways concerning redox homeostasis and xenobiotics, macromolecules, and iron metabolism. Being the master regulator of antioxidant system, Nrf2 controls cellular fate, influencing cell proliferation, differentiation, apoptosis, resistance to therapy, and senescence processes, as well as infection disease success. Because Nrf2 is the key coordinator of cell defence mechanisms, dysregulation of its signaling has been associated with carcinogenic phenomena and infectious and age-related diseases. Deregulation of this cytoprotective system may also interfere with immune response. Oxidative burst, one of the main microbicidal mechanisms, could be impaired during the initial phagocytosis of pathogens, which could lead to the successful establishment of infection and promote susceptibility to infectious diseases. There is still a knowledge gap to fill regarding the molecular mechanisms by which Nrf2 orchestrates such complex networks involving multiple pathways. This review describes the role of Nrf2 in non-pathogenic and pathogenic cells.

TRIM21 deficiency protects against atrial inflammation and remodeling post myocardial infarction by attenuating oxidative stress

Atrial remodeling is a major contributor to the onset of atrial fibrillation (AF) after myocardial infarction (MI). Tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin protein ligase, is associated with pathological cardiac remodeling and dysfunction. However, the role of TRIM21 in postmyocardial infarction atrial remodeling and subsequent AF remains unclear. This study investigated the role of TRIM21 in post myocardial infarction atrial remodeling using TRIM21 knockout mice and explored the underlying mechanisms by overexpressing TRIM21 in HL-1 atrial myocytes using a lentiviral vector. The expression of TRIM21 in the left atrium of the mouse MI model was significantly elevated. TRIM21 deficiency alleviated MI-induced atrial oxidative damage, Cx43 downregulation, atrial fibrosis and enlargement, and abnormalities in electrocardiogram parameters (prolongation of the P-wave and PR interval). TRIM21 overexpression in atrial myocyte HL-1 cells further enhanced oxidative damage and Cx43 downregulation, whereas these effects were reversed by the reactive oxygen species scavenger N-acetylcysteine. The findings suggest that TRIM21 likely induces Nox2 expression mechanistically by activating the NF-κB pathway, which in turn leads to myocardial oxidative damage, inflammation, and atrial remodeling.

Activation of neuronal NADPH oxidase NOX2 promotes inflammatory neurodegeneration

Strong evidence indicates critical roles of NADPH oxidase (a key superoxide-producing enzyme complex during inflammation) in activated microglia for mediating neuroinflammation and neurodegeneration. However, little is known about roles of neuronal NADPH oxidase in neurodegenerative diseases. This study aimed to investigate expression patterns, regulatory mechanisms and pathological roles of neuronal NADPH oxidase in inflammation-associated neurodegeneration. The results showed persistent upregulation of NOX2 (gp91phox; the catalytic subunit of NADPH oxidase) in both microglia and neurons in a chronic mouse model of Parkinson's disease (PD) with intraperitoneal LPS injection and LPS-treated midbrain neuron-glia cultures (a cellular model of PD). Notably, NOX2 was found for the first time to exhibit a progressive and persistent upregulation in neurons during chronic neuroinflammation. While primary neurons and N27 neuronal cells displayed basal expression of NOX1, NOX2 and NOX4, significant upregulation only occurred in NOX2 but not NOX1 or NOX4 under inflammatory conditions. Persistent NOX2 upregulation was associated with functional outcomes of oxidative stress including increased ROS production and lipid peroxidation. Neuronal NOX2 activation displayed membrane translocation of cytosolic p47phox subunit and was inhibited by apocynin and diphenyleneiodonium chloride (two widely-used NADPH oxidase inhibitors). Importantly, neuronal ROS production, mitochondrial dysfunction and degeneration induced by inflammatory mediators in microglia-derived conditional medium were blocked by pharmacological inhibition of neuronal NOX2. Furthermore, specific deletion of neuronal NOX2 prevented LPS-elicited dopaminergic neurodegeneration in neuron-microglia co-cultures separately grown in the transwell system. The attenuation of inflammation-elicited upregulation of NOX2 in neuron-enriched and neuron-glia cultures by ROS scavenger N-acetylcysteine indicated a positive feedback mechanism between excessive ROS production and NOX2 upregulation. Collectively, our findings uncovered crucial contribution of neuronal NOX2 upregulation and activation to chronic neuroinflammation and inflammation-related neurodegeneration. This study reinforced the importance of developing NADPH oxidase-targeting therapeutics for neurodegenerative diseases.

The novel TAK1 inhibitor handelin inhibits NF-κB and AP-1 activity to alleviate elastase-induced emphysema in mice

AIMS

Emphysema, one of the two major components of chronic obstructive pulmonary disease (COPD), is driven by aberrant inflammatory responses and associated with irreversible lung parenchymal destruction. As effective therapy for preventing or treating COPD/emphysema is yet unavailable, development of molecular targets and therapeutic agents for COPD/emphysema is required.

MAIN METHODS AND KEY FINDINGS

We identified handelin-a guaianolide dimer of sesquiterpene lactones- from a chemical library of 431 natural products as it exhibited potent inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) and reactive oxygen species (ROS) production, LPS-induced activation of nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK)/AP-1, and expression of proinflammatory mediators in macrophage cells. In silico docking and biochemical studies enabled the identification of the ATP-binding pocket of transforming growth factor beta-activated kinase 1 (TAK1), a kinase upstream of NF-κB and MAPK/AP-1 pathways, as a molecular target for handelin. Moreover, oral administration of handelin (10 mg/kg) suppressed elastase-induced development of emphysematous phenotypes, including lung function disturbance, airspace enlargement, and increases in the level of neutrophils and CD8+ T cells in lung tissues, without overt toxicity. Consistent with in vitro results, analyses of lung tissues revealed that treatment with handelin suppressed elastase-induced NF-κB and AP-1 activation in the lungs, followed by downregulation of their targets including interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and matrix metalloproteinase 9 (MMP9).

SIGNIFICANCE

These findings suggest that handelin, as a TAK1 inhibitor, effectively prevents development of emphysema in an elastase-induced mouse model by inhibiting a proinflammatory mediators mediated by NF-κB and AP-1.

Insight into the transcription factors regulating Ischemic Stroke and Glioma in Response to Shared Stimuli

Cerebral ischemic stroke and glioma are the two leading causes of patient mortality globally. Despite physiological variations, 1 in 10 people who have an ischemic stroke go on to develop brain cancer, most notably gliomas. In addition, glioma treatments have also been shown to increase the risk of ischemic strokes. Stroke occurs more frequently in cancer patients than in the general population, according to traditional literature. Unbelievably, these events share multiple pathways, but the precise mechanism underlying their co-occurrence remains unknown. Transcription factors (TFs), the main components of gene expression programmes, finally determine the fate of cells and homeostasis. Both ischemic stroke and glioma exhibit aberrant expression of a large number of TFs, which are strongly linked to the pathophysiology and progression of both diseases. The precise genomic binding locations of TFs and how TF binding ultimately relates to transcriptional regulation remain elusive despite a strong interest in understanding how TFs regulate gene expression in both stroke and glioma. As a result, the importance of continuing efforts to understand TF-mediated gene regulation is highlighted in this review, along with some of the primary shared events in stroke and glioma.

Maslinic acid attenuates UVB-induced oxidative damage in HFF-1 cells

BACKGROUND

Oxidative damage is one of the major mechanisms of ultraviolet B (UVB)-induced damage to the skin. Maslinic acid (MA) is a natural compound of pentacyclic triterpene acids. It has been proved to have anti-inflammatory and antioxidant properties.

OBJECTIVE

This study aimed to explore the effects of MA on oxidative damage in human foreskin fibroblast cells (HFF-1) and the potential molecular mechanisms.

METHODS

A specific dose of UVB radiation was used to induce oxidative damage in HFF-1. Based on this, we performed measurements of cell proliferation, reactive oxygen species (ROS) levels, antioxidant enzyme activity, inflammation-related mediators, and NF-κB nuclear localization with or without the addition of MA.

RESULTS

MA significantly promoted cell proliferation viability at 10 and 20 μM. The addition of MA 24 h before UVB irradiation was more effective at enhancing cell proliferation and also produced lower ROS levels compared to co-cultured fibroblasts and MA for 24 h after irradiation. However, there was no statistically significant difference between groups at concentrations of 10 and 20 μM. The pretreatment group with MA had elevated superoxide dismutase and catalase activities, decreased IL-6 generation, and lowered mRNA levels of IL-6, TNF-α and MMP3 in comparison with the UVB-irradiated group without additional MA. Meanwhile, the nuclear translocation of NF-κB and the degradation of IκB were inhibited by MA pretreatment.

CONCLUSION

Taken together, these findings suggest that MA may alleviate UVB-induced oxidative damage in HFF-1 by inhibiting the nuclear translocation of NF-κB.

Ormeloxifene, a selective estrogen receptor modulator, protects against pulmonary hypertension

PURPOSE

Protective effect of 17β-estradiol is well-known in pulmonary hypertension. However, estrogen-based therapy may potentially increase the risk of breast cancer, necessitating a search for novel drugs. This study, therefore, investigated the ameliorative effects of a selective estrogen receptor modulator, ormeloxifene, in pulmonary hypertension.

METHODS

Cardiomyocytes (H9C2) and human pulmonary arterial smooth muscle cells (HPASMCs) were exposed to hypoxia (1% O₂) for 42 and 96 h, respectively, with or without ormeloxifene pre-treatment (1 μM). Also, female (ovary-intact or ovariectomized) and male Sprague-Dawley rats received monocrotaline (60 mg/kg, once, subcutaneously), with or without ormeloxifene treatment (2.5 mg/kg, orally) for four weeks.

RESULTS

Hypoxia dysregulated 17β-hydroxysteroid dehydrogenase (17βHSD) 1 & 2 expressions, reducing 17β-estradiol production and estrogen receptors α and β in HPASMC but increasing estrone, proliferation, inflammation, oxidative stress, and mitochondrial dysfunction. Similarly, monocrotaline decreased plasma 17β-estradiol and uterine weight in ovary-intact rats. Further, monocrotaline altered 17βHSD1 & 2 expressions and reduced estrogen receptors α and β, increasing right ventricular pressure, proliferation, inflammation, oxidative stress, endothelial dysfunction, mitochondrial dysfunction, and vascular remodeling in female and male rats, with worsened conditions in ovariectomized rats. Ormeloxifene was less uterotrophic; however, it attenuated both hypoxia and monocrotaline effects by improving pulmonary 17β-estradiol synthesis. Furthermore, ormeloxifene decreased cardiac hypertrophy and right ventricular remodeling induced by hypoxia and monocrotaline.

CONCLUSION

This study demonstrates that ormeloxifene promoted pulmonary 17β-estradiol synthesis, alleviated inflammation, improved the NOX4/HO1/Nrf/PPARγ/PGC-1α axis, and attenuated pulmonary hypertension. It is evidently safe at tested concentrations and may be effectively repurposed for pulmonary hypertension treatment.

Isolation of the Anti-Inflammatory Agent Myceliostatin from a Methionine-Enriched Culture of Myceliophthora thermophila ATCC 42464

Safe and effective nonsteroidal anti-inflammatory drugs are needed. Meanwhile, addition of amino acids to cultures of microorganisms is likely to increase the possibility of novel secondary metabolite isolation. In the course of screening for anti-inflammatory agents using cellular lipopolysaccharide (LPS)-induced nitric oxide (NO) production, two new related compounds with the myceliothermophin structure from a methionine-enriched culture of Myceliophthora thermophila ATCC 42464 were isolated. The new compounds have an additional methylthio group on the myceliothermophin structure and were named myceliostatins A and B. Both compounds inhibited LPS-induced NO production at nontoxic concentrations in macrophage-like mouse monocytic leukemia RAW264.7 cells. Myceliostatin B inhibited the expression of LPS-induced iNOS, IL-6, and IL-1β and the upstream NF-κB activity in situ and in vitro. Finally, it was found to inhibit NF-κB binding to DNA in the reconstruction system with purified p65. Myceliostatin B also inhibited LPS-induced reactive oxygen species (ROS) production. Thus, myceliostatin B, a novel compound derived from M. thermophila, was found to be a new anti-inflammatory and antioxidant compound directly inhibiting NF-κB.

Nicotinamide Adenosine Dinucleotide Phosphate Oxidase-Mediated Signaling in Cardiac Remodeling

Significance: Reactive oxygen species (ROS) play a key role in the pathogenesis of cardiac remodeling and the subsequent progression to heart failure (HF). Nicotinamide adenosine dinucleotide phosphate (NADPH) oxidases (NOXs) are one of the major sources of ROS and are expressed in different heart cell types, including cardiomyocytes, endothelial cells, fibroblasts, and inflammatory cells. Recent Advances: NOX-derived ROS are usually produced in a regulated and spatially confined fashion and typically linked to specific signaling. The two main cardiac isoforms, namely nicotinamide adenine dinucleotide phosphate oxidase isoform 2 (NOX2) and nicotinamide adenine dinucleotide phosphate oxidase isoform 4 (NOX4), possess different biochemical and (patho)physiological properties and exert distinct effects on the cardiac phenotype in many settings. Recent work has defined important cell-specific effects of NOX2 that contribute to pathological cardiac remodeling and dysfunction. NOX4, on the other hand, may exert protective effects by stimulating adaptive stress responses, with recent data showing that NOX4-mediated signaling regulates transcription and metabolism in the heart. Critical Issues: The inhibition of NOX2 appears to be a very promising therapeutic target to ameliorate pathological cardiac remodeling. If the beneficial effects of NOX4 can be enhanced, this might be a unique approach to boosting adaptive responses and thereby impact cell survival, activation, contractility, and growth. Future Directions: Increasing knowledge regarding the intricacies of NOX-mediated signaling may yield tractable therapeutic targets, in contrast to the non-specific targeting of oxidative stress. Antioxid. Redox Signal. 38, 371-387.

Elevated Serum NOX2 Levels Contribute to Delayed Cerebral Ischemia and a Poor Prognosis After Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study

Background

NADPH oxidase 2 (NOX2) is highly expressed in injured brain tissues. We determined serum NOX2 levels of aneurysmal subarachnoid hemorrhage (aSAH) patients and further investigated correlation of serum NOX2 levels with disease severity, delayed cerebral ischemia (DCI) plus prognosis after aSAH.

Methods

Serum NOX2 levels were measured in 123 aSAH patients and 123 healthy controls. World Federation of Neurological Surgeons scale (WFNS) score and modified Fisher (mFisher) score were utilized to assess disease severity. Modified Rankin scale (mRS) score was used to evaluate the clinical prognosis at 90 days after aSAH. Relations of serum NOX2 levels to DCI and 90-day poor prognosis (mRS score of 3-6) were analyzed using multivariate analysis. Receiver operating characteristic curve (ROC) was built to evaluate the prognostic predictive capability.

Results

Serum NOX2 levels in aSAH patients, compared with healthy controls, were significantly increased, and were independently correlated with WFNS score, mFisher score and post-stroke 90-day mRS score. Patients with poor prognosis or DCI had significantly higher serum NOX2 levels than other remainders, and serum NOX2 levels independently predicted 90-day poor prognosis and DCI. Serum NOX2 had high prognosis and DCI predictive abilities, and their areas under ROC curve were similar to those of WFNS score and mFisher score.

Conclusion

Serum NOX2 levels are significantly associated with hemorrhage severity, poor 90-day prognosis and DCI in aSAH patients. Hence, complement NOX2 may serve as a potential prognostic biomarker after aSAH.

NADPH oxidase and endoplasmic reticulum stress is associated with neuronal degeneration in orbitofrontal cortex of individuals with alcohol use disorder

Many disorders of the central nervous system (CNS), including alcohol use disorder (AUD), are associated with induction of proinflammatory neuroimmune signalling and neurodegeneration. In previous studies, we found increased expression of Toll-like receptors (TLRs), activated NF-κB p65 (RELA), and other proinflammatory signalling molecules. Proinflammatory NADPH oxidases generate reactive oxygen species, which are linked to neurodegeneration. We tested the hypothesis that AUD increased RELA activation increases NADPH oxidase-oxidative stress and endoplasmic reticulum (ER) stress cell death cascades in association with neuronal cell death in the human orbitofrontal cortex (OFC). In the AUD OFC, we report mRNA induction of several NADPH oxidases, the dual oxidase DUOX2, and the oxidative stress lipid peroxidation marker 4-HNE and the DNA oxidation marker 8-OHdG that correlate with RELA, a marker of proinflammatory NF-κB activation. This was accompanied by increased expression of the ER stress-associated regulator protein glucose-regulated protein 78 (GRP78), transmembrane sensors activating transcription factor 6 (ATF6), protein kinase RNA-like endoplasmic reticulum kinase (PERK), and inositol-requiring kinase/endonuclease 1 (pIRE1), and the pro-apoptotic transcription factor C/EBP homologous protein (CHOP). Expression of NADPH oxidase-oxidative stress markers correlate with ER stress-associated molecules. Induction of oxidative stress and ER stress signalling pathways correlate with expression of cell death-associated caspases and neuronal cell loss. These data support the hypothesis that proinflammatory RELA-mediated induction of NADPH oxidase-oxidative stress and ER stress-associated signalling cascades is associated with neuronal cell death in the post-mortem human OFC of individuals with AUD.

Melatonin and inflammatory bowel disease: From basic mechanisms to clinical application

Inflammatory bowel disease is a chronic inflammatory disease and has periods of recurrence and remission. Improper immune responses to gut flora bacteria, along with genetic susceptibility, appear to be involved in causing this complex disease. It seems dysbiosis and oxidative stress may also be involved in IBD pathogenesis. A significant number of clinical studies have shown an interesting association between sleep disturbances and IBD. Studies in animal models have also shown that sleep deprivation has a significant effect on the pathogenesis of IBD and can aggravate inflammation. These interesting findings have drawn attention to melatonin, a sleep-related hormone. Melatonin is mainly produced by the pineal gland, but many tissues in the body, including the intestines, can produce it. Melatonin can have an interesting effect on the pathogenesis of IBD. Melatonin can enhance the intestinal mucosal barrier, alter the composition of intestinal bacteria in favor of bacteria with anti-inflammatory properties, regulate the immune response, alleviate inflammation and attenuate oxidative stress. It seems that, melatonin supplementation is effective in relieving inflammation and healing intestinal ulcers in IBD animal models. Some clinical studies have also shown that melatonin supplementation as an adjuvant therapy may be helpful in reducing disease activity in IBD patients. In this review article, in addition to reviewing the effects of sleep disturbances and melatonin on key mechanisms involved in the pathogenesis of IBD, we will review the findings of clinical studies regarding the effects of melatonin supplementation on IBD treatment.

Pharmacological Inhibition of Lysine-Specific Demethylase 1A Reduces Atherosclerotic Lesion Formation in Apolipoprotein E-Deficient Mice by a Mechanism Involving Decreased Oxidative Stress and Inflammation; Potential Implications in Human Atherosclerosis

Dysregulated epigenetic mechanisms promote transcriptomic and phenotypic alterations in cardiovascular diseases. The role of histone methylation-related pathways in atherosclerosis is largely unknown. We hypothesize that lysine-specific demethylase 1A (LSD1/KDM1A) regulates key molecular effectors and pathways linked to atherosclerotic plaque formation. Human non-atherosclerotic and atherosclerotic tissue specimens, ApoE-/- mice, and in vitro polarized macrophages (Mac) were examined. Male ApoE-/- mice fed a normal/atherogenic diet were randomized to receive GSK2879552, a highly specific LSD1 inhibitor, or its vehicle, for 4 weeks. The mRNA and protein expression levels of LSD1/KDM1A were significantly elevated in atherosclerotic human carotid arteries, atherosclerotic aortas of ApoE-/- mice, and M1-Mac. Treatment of ApoE-/- mice with GSK2879552 significantly reduced the extent of atherosclerotic lesions and the aortic expression of NADPH oxidase subunits (Nox1/2/4, p22phox) and 4-hydroxynonenal-protein adducts. Concomitantly, the markers of immune cell infiltration and vascular inflammation were significantly decreased. LSD1 blockade down-regulated the expression of genes associated with Mac pro-inflammatory phenotype. Nox subunit transcript levels were significantly elevated in HEK293 reporter cells overexpressing LSD1. In experimental atherosclerosis, LSD1 mediates the up-regulation of molecular effectors connected to oxidative stress and inflammation. Together, these data indicate that LSD1-pharmacological interventions are novel targets for supportive therapeutic strategies in atherosclerosis.

A comprehensive review on modulation of SIRT1 signaling pathways in the immune system of COVID-19 patients by phytotherapeutic melatonin and epigallocatechin-3-gallate

SARS-CoV-2 infection has now become the world's most significant health hazard, with the World Health Organization declaring a pandemic on March 11, 2020. COVID-19 enters the lungs through angiotensin-converting enzyme 2 (ACE2) receptors, alters various signaling pathways, and causes immune cells to overproduce cytokines, resulting in mucosal inflammation, lung damage, and multiple organ failure in COVID-19 patients. Although several antiviral medications have been effective in managing the virus, they have not been effective in lowering the inflammation and symptoms of the illness. Several studies have found that epigallocatechin-3-gallate and melatonin upregulate sirtuins proteins, which leads to downregulation of pro-inflammatory gene transcription and NF-κB, protecting organisms from oxidative stress in autoimmune, respiratory, and cardiovascular illnesses. As a result, the purpose of this research is to understand more about the molecular pathways through which these phytochemicals affect COVID-19 patients' impaired immune systems, perhaps reducing hyperinflammation and symptom severity. PRACTICAL APPLICATIONS: Polyphenols are natural secondary metabolites that are found to be present in plants. EGCG a polyphenol belonging to the flavonoid family in tea has potent anti-inflammatory and antioxidative properties that helps to counter the inflammation and oxidative stress associated with many neurodegenerative diseases. Melatonin, another strong antioxidant in plants, has been shown to possess antiviral function and alleviate oxidative stress in many inflammatory diseases. In this review, we propose an alternative therapy for COVID-19 patients by supplementing their diet with these nutraceuticals that perhaps by modulating sirtuin signaling pathways counteract cytokine storm and oxidative stress, the root causes of severe inflammation and symptoms in these patients.

Involvement of AGE and Its Receptors in the Pathogenesis of Hypertension in Elderly People and Its Treatment

Both systolic and diastolic blood pressures increase with age up to 50 to 60 years of age. After 60 years of age systolic pressure rises to 84 years of age but diastolic pressure remains stable or even decreases. In the oldest age group (85-99 years), the systolic blood pressure (SBP) is high and diastolic pressure (DBP) is the lowest. Seventy percent of people older than 65 years are hypertensive. This paper deals with the role of advanced glycation end products (AGE) and its cell receptor (RAGE) and soluble receptor (sRAGE) in the development of hypertension in the elderly population. Plasma/serum levels of AGE are higher in older people as compared with younger people. Serum levels of AGE are positively correlated with age, arterial stiffness, and hypertension. Low serum levels of sRAGE are associated with arterial stiffness and hypertension. Levels of sRAGE are negatively correlated with age and blood pressure. Levels of sRAGE are lower in patients with arterial stiffness and hypertension than patients with high levels of sRAGE. AGE could induce hypertension through numerous mechanisms including, cross-linking with collagen, reduction of nitric oxide, increased expression of endothelin-1, and transforming growth factor-β (TGF-β). Interaction of AGE with RAGE could produce hypertension through the generation of reactive oxygen species, increased sympathetic activity, activation of nuclear factor-kB, and increased expression of cytokines, cell adhesion molecules, and TGF- β. In conclusion, the AGE-RAGE axis could be involved in hypertension in elderly people. Treatment for hypertension in elderly people should be targeted at reduction of AGE levels in the body, prevention of AGE formation, degradation of AGE in vivo, downregulation of RAGE expression, blockade of AGE-RAGE interaction, upregulation of sRAGE expression, and use of antioxidants.

Preconditioning by voluntary wheel running attenuates later neuropathic pain via nuclear factor E2-related factor 2 antioxidant signaling in rats

ABSTRACT

Animal and human studies have shown that exercise prior to nerve injury prevents later chronic pain, but the mechanisms of such preconditioning remain elusive. Given that exercise acutely increases the formation of free radicals, triggering antioxidant compensation, we hypothesized that voluntary running preconditioning would attenuate neuropathic pain by supporting redox homeostasis after sciatic nerve injury in male and female rats. We show that 6 weeks of voluntary wheel running suppresses neuropathic pain development induced by chronic constriction injury across both sexes. This attenuation was associated with reduced nitrotyrosine immunoreactivity-a marker for peroxynitrite-at the sciatic nerve injury site. Our data suggest that prior voluntary wheel running does not reduce the production of peroxynitrite precursors, as expression levels of inducible nitric oxide synthase and NADPH oxidase 2 were unchanged. Instead, voluntary wheel running increased superoxide scavenging by elevating expression of superoxide dismutases 1 and 2. Prevention of neuropathic pain was further associated with the activation of the master transcriptional regulator of the antioxidant response, nuclear factor E2-related factor 2 (Nrf2). Six weeks of prior voluntary wheel running increased Nrf2 nuclear translocation at the sciatic nerve injury site; in contrast, 3 weeks of prior wheel running, which failed to prevent neuropathic pain, had no effect on Nrf2 nuclear translocation. The protective effects of prior voluntary wheel running were mediated by Nrf2, as suppression was abolished across both sexes when Nrf2 activation was blocked during the 6-week running phase. This study provides insight into the mechanisms by which physical activity may prevent neuropathic pain. Preconditioning by voluntary wheel running, terminated prior to nerve injury, suppresses later neuropathic pain in both sexes, and it is modulated through the activation of Nrf2-antioxidant signaling.

Delayed Onset Muscle Soreness and Critical Neural Microdamage-Derived Neuroinflammation

Piezo2 transmembrane excitatory mechanosensitive ion channels were identified as the principal mechanotransduction channels for proprioception. Recently, it was postulated that Piezo2 channels could be acutely microdamaged on an autologous basis at proprioceptive Type Ia terminals in a cognitive demand-induced acute stress response time window when unaccustomed or strenuous eccentric contractions are executed. One consequence of this proposed transient Piezo2 microinjury could be a VGLUT1/Ia synaptic disconnection on motoneurons, as we can learn from platinum-analogue chemotherapy. A secondary, harsher injury phase with the involvement of polymodal Aδ and nociceptive C-fibers could follow the primary impairment of proprioception of delayed onset muscle soreness. Repetitive reinjury of these channels in the form of repeated bout effects is proposed to be the tertiary injury phase. Notably, the use of proprioception is associated with motor learning and memory. The impairment of the monosynaptic static phase firing sensory encoding of the affected stretch reflex could be the immediate consequence of the proposed Piezo2 microdamage leading to impaired proprioception, exaggerated contractions and reduced range of motion. These transient Piezo2 channelopathies in the primary afferent terminals could constitute the critical gateway to the pathophysiology of delayed onset muscle soreness. Correspondingly, fatiguing eccentric contraction-based pathological hyperexcitation of the Type Ia afferents induces reactive oxygen species production-associated neuroinflammation and neuronal activation in the spinal cord of delayed onset muscle soreness.

Single-Cell Analysis Reveals the Range of Transcriptional States of Circulating Human Neutrophils

Neutrophils are the most abundant leukocytes in human blood and are essential components of innate immunity. Until recently, neutrophils were considered homogeneous and transcriptionally inactive cells, but both concepts are being challenged. Single-cell RNA sequencing (scRNA-seq) offers an unbiased view of cells along a continuum of transcriptional states. However, the use of scRNA-seq to characterize neutrophils has proven technically difficult, explaining in part the paucity of published single-cell data on neutrophils. We have found that modifications to the data analysis pipeline, rather than to the existing scRNA-seq chemistries, can significantly increase the detection of human neutrophils in scRNA-seq. We have then applied a modified pipeline to the study of human peripheral blood neutrophils. Our findings indicate that circulating human neutrophils are transcriptionally heterogeneous cells, which can be classified into one of four transcriptional clusters that are reproducible among healthy human subjects. We demonstrate that peripheral blood neutrophils shift from relatively immature (Nh0) cells, through a transitional phenotype (Nh1), into one of two end points defined by either relative transcriptional inactivity (Nh2) or high expression of type I IFN-inducible genes (Nh3). Transitions among states are characterized by the expression of specific transcription factors. By simultaneously measuring surface proteins and intracellular transcripts at the single-cell level, we show that these transcriptional subsets are independent of the canonical surface proteins that are commonly used to define and characterize human neutrophils. These findings provide a new view of human neutrophil heterogeneity, with potential implications for the characterization of neutrophils in health and disease.