Induction of COX-2 enzyme and down-regulation of COX-1 expression by lipopolysaccharide (LPS) control prostaglandin E2 production in astrocytes

Eicosanoid signaling in neuroinflammation associated with Alzheimer's disease

Alzheimer's disease (AD) is a prevalent neurodegenerative condition affecting a substantial portion of the global population. It is marked by a complex interplay of factors, including the accumulation of amyloid plaques and tau tangles within the brain, leading to neuroinflammation and neuronal damage. Recent studies have underscored the role of free lipids and their derivatives in the initiation and progression of AD. Eicosanoids, metabolites of polyunsaturated fatty acids like arachidonic acid (AA), emerge as key players in this scenario. Remarkably, eicosanoids can either promote or inhibit the development of AD, and this multifaceted role is determined by how eicosanoid signaling influences the immune responses within the brain. However, the precise molecular mechanisms dictating the dual role of eicosanoids in AD remain elusive. In this comprehensive review, we explore the intricate involvement of eicosanoids in neuronal function and dysfunction. Furthermore, we assess the therapeutic potential of targeting eicosanoid signaling pathways as a viable strategy for mitigating or halting the progression of AD.

Platelet-rich plasma attenuates the UPEC-induced cystitis via inhibiting MMP-2,9 activities and downregulation of NGF and VEGF in Canis Lupus Familiaris model

One of the most prevalent disorders of the urinary system is urinary tract infection, which is mostly brought on by uropathogenic Escherichia coli (UPEC). The objective of this study was to evaluate the regenerative therapeutic and antibacterial efficacy of PRP for induced bacterial cystitis in dogs in comparison to conventional antibiotics. 25 healthy male mongrel dogs were divided into 5 groups (n = 5). Control negative group that received neither induced infection nor treatments. 20 dogs were randomized into 4 groups after two weeks of induction of UPEC cystitis into; Group 1 (control positive; G1) received weekly intravesicular instillation of sodium chloride 0.9%. Group 2 (syst/PRP; G2), treated with both systemic intramuscular antibiotic and weekly intravesicular instillation of PRP; Group 3 (PRP; G3), treated with weekly intravesicular instillation of PRP, and Group 4 (syst; G4) treated with an intramuscular systemic antibiotic. Animals were subjected to weekly clinical, ultrasonographic evaluation, urinary microbiological analysis, and redox status biomarkers estimation. Urinary matrix metalloproteinases (MMP-2, MMP-9) and urinary gene expression for platelet-derived growth factor -B (PDGF-B), nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) were measured. At the end of the study, dogs were euthanized, and the bladder tissues were examined macroscopically, histologically, and immunohistochemically for NF-κB P65 and Cox-2. The PRP-treated group showed significant improvement for all the clinical, Doppler parameters, and the urinary redox status (p < 0.05). The urinary MMPs activity was significantly decreased in the PRP-treated group and the expression level of urinary NGF and VEGF were downregulated while PDGFB was significantly upregulated (p < 0.05). Meanwhile, the urinary viable cell count was significantly reduced in all treatments (P < 0.05). Gross examination of bladder tissue showed marked improvement for the PRP-treated group, expressed in the histopathological findings. Immunohistochemical analysis revealed a marked increase in Cox-2 and NF-κB P65 in the PRP-treated group (P < 0.05). autologous CaCl2-activated PRP was able to overcome the bacterial infection, generating an inflammatory environment to overcome the old one and initiate tissue healing. Hence, PRP is a promising alternative therapeutic for UPEC cystitis instead of conventional antibiotics.

A Narrative Review of the Published Pre-Clinical Evaluations: Multiple Effects of Arachidonic Acid, its Metabolic Enzymes and Metabolites in Epilepsy

Arachidonic acid (AA), an important polyunsaturated fatty acid in the brain, is hydrolyzed by a direct action of phospholipase A2 (PLA2) or through the combined action of phospholipase C and diacylglycerol lipase, and released into the cytoplasm. Various derivatives of AA can be synthesized mainly through the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 (P450) enzyme pathways. AA and its metabolic enzymes and metabolites play important roles in a variety of neurophysiological activities. The abnormal metabolites and their catalytic enzymes in the AA cascade are related to the pathogenesis of various central nervous system (CNS) diseases, including epilepsy. Here, we systematically reviewed literatures in PubMed about the latest randomized controlled trials, animal studies and clinical studies concerning the known features of AA, its metabolic enzymes and metabolites, and their roles in epilepsy. The exclusion criteria include non-original studies and articles not in English.

Barbaloin Protects Pentylenetetrazol-Induced Cognitive Deficits in Rodents via Modulation of Neurotransmitters and Inhibition of Oxidative-Free-Radicals-Led Inflammation

BACKGROUND

Epilepsy is defined by an excessive level of activity in the neurons and coordinated bursts of electrical activity, resulting in the occurrence of seizure episodes. The precise cause of epileptogenesis remains uncertain; nevertheless, the etiology of epilepsy may involve neuroinflammation, oxidative stress, and malfunction of the neurotransmitter system.

OBJECTIVE

The goal of this investigation was to assess barbaloin's protective properties with respect to pentylenetetrazol (PTZ)-)-induced cognitive deficits in rats via antioxidative, anti-inflammatory, and neurotransmitter-modulating effects.

METHODS

Wistar rats were subjected to PTZ [40 mg/kg (i.p.)], which induced cognitive decline. Behavior assessment using a kindling score, open-field test (OFT), novel object recognition test (NORT), and assays for superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), malondialdehyde (MDA), acetylcholinesterase (AChE), caspase-3, nitric oxide (NO), interleukins-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6, nuclear factor kappa-B (NF-κB), Bcl-2 and Bax, and neurotransmitter levels [GABA, DA, NE, and serotonin (5-HT)] were performed.

RESULTS

The treatment of rats with barbaloin resulted in behavior improvement and significant changes in the levels of GSH, SOD, CAT, MDA, AChE, NO, IL-6, IL-1β, TNF-α, NF-κB, caspase-3, Bcl-2, and Bax compared to the PTZ control group. Barbaloin treatment resulted in notable changes in neurotransmitter levels (GABA, NE, 5-HT, DA) compared to the PTZ group.

CONCLUSIONS

The ongoing study has gathered evidence indicating that the injection of barbaloin has resulted in significant improvements in cognitive performance in rats. This is achieved by inhibiting oxidative stress, enhancing the activity of natural antioxidant enzymes, reducing cytokine levels, and increasing the levels of neurotransmitters in the brain. These results were detected in comparison to a PTZ control and can be attributed to the potent anti-inflammatory and antioxidant capabilities of barbaloin, which could be linked to its neuroprotective properties. Barbaloin may potentially increase cognitive decline and boost neuronal survival by altering the expression of Bax, caspase-3, Bcl-2.

Reactive spinal glia convert 2-AG to prostaglandins to drive aberrant astroglial calcium signaling

The endogenous cannabinoid 2-arachidonoylglycerol (2-AG) influences neurotransmission in the central nervous system mainly by activating type 1 cannabinoid receptor (CB1). Following its release, 2-AG is broken down by hydrolases to yield arachidonic acid, which may subsequently be metabolized by cyclooxygenase-2 (COX-2). COX-2 converts arachidonic acid and also 2-AG into prostanoids, well-known inflammatory and pro-nociceptive mediators. Here, using immunohistochemical and biochemical methods and pharmacological manipulations, we found that reactive spinal astrocytes and microglia increase the expression of COX-2 and the production of prostaglandin E2 when exposed to 2-AG. Both 2-AG and PGE2 evoke calcium transients in spinal astrocytes, but PGE2 showed 30% more efficacy and 55 times more potency than 2-AG. Unstimulated spinal dorsal horn astrocytes responded to 2-AG with calcium transients mainly through the activation of CB1. 2-AG induced exaggerated calcium transients in reactive astrocytes, but this increase in the frequency and area under the curve of calcium signals was only partially dependent on CB1. Instead, aberrant calcium transients were almost completely abolished by COX-2 inhibition. Our results suggest that both reactive spinal astrocytes and microglia perform an endocannabinoid-prostanoid switch to produce PGE2 at the expense of 2-AG. PGE2 in turn is responsible for the induction of aberrant astroglial calcium signals which, together with PGE2 production may play role in the development and maintenance of spinal neuroinflammation-associated disturbances such as central sensitization.

Real time changes in the expression of eicosanoid synthesizing enzymes during inflammation

Immune responses during inflammation involve complex, well-coordinated lipid signaling pathways. Eicosanoids are a class of lipid signaling molecules derived from polyunsaturated fatty acids such as arachidonic acid and constitute a major network that controls inflammation and its subsequent resolution. Arachidonic acid is metabolized by enzymes in three different pathways to form a variety of lipid metabolites that can be either pro- or anti-inflammatory. Therefore, an understanding of the time-dependent gene expression, lipid metabolite profiles and cytokine profiles during the initial inflammatory response is necessary, as it will allow for the design of time-dependent therapeutics. Herein, we investigate the multi-level regulation of this process. After stimulating RAW 264.7 cells, a mouse-derived macrophage cell line commonly used to examine inflammatory responses, we examine the gene expression of 44 relevant lipid metabolizing enzymes from the different eicosanoid synthesizing classes. We also measure the formation of lipid metabolites and production of cytokines at selected time points. Results reveal a dynamic relationship between the time-course of inflammation dependent gene expression of the three eicosanoid synthesizing enzymes.

Role of ferroptosis pathways in neuroinflammation and neurological disorders: From pathogenesis to treatment

Ferroptosis is a newly discovered non-apoptotic and iron-dependent type of cell death. Ferroptosis mainly takes place owing to the imbalance of anti-oxidation and oxidation in the body. It is regulated via a number of factors and pathways both inside and outside the cell. Ferroptosis is closely linked with brain and various neurological disorders (NDs). In the human body, the brain contains the highest levels of polyunsaturated fatty acids, which are known as lipid peroxide precursors. In addition, there is also a connection of glutathione depletion and lipid peroxidation with NDs. There is growing evidence regarding the possible link between neuroinflammation and multiple NDs, such as Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, and stroke. Recent studies have demonstrated that disruptions of lipid reactive oxygen species (ROS), glutamate excitatory toxicity, iron homeostasis, and various other manifestations linked with ferroptosis can be identified in various neuroinflammation-mediated NDs. It has also been reported that damage-associated molecular pattern molecules including ROS are generated during the events of ferroptosis and can cause glial activation via activating neuroimmune pathways, which subsequently leads to the generation of various inflammatory factors that play a role in various NDs. This review summarizes the regulation pathways of ferroptosis, the link between ferroptosis as well as inflammation in NDs, and the potential of a range of therapeutic agents that can be used to target ferroptosis and inflammation in the treatment of neurological disorders.

Analysis of the Model of Atherosclerosis Formation in Pig Hearts as a Result of Impaired Activity of DNA Repair Enzymes

Excessive consumption of food rich in saturated fatty acids and carbohydrates can lead to metabolic disturbances and cardiovascular disease. Hyperlipidemia is a significant risk factor for acute cardiac events due to its association with oxidative stress. This leads to arterial wall remodeling, including an increase in the thickness of the intima media complex (IMT), and endothelial dysfunction leading to plaque formation. The decreased nitric oxide synthesis and accumulation of lipids in the wall result in a reduction in the vasodilating potential of the vessel. This study aimed to establish a clear relationship between markers of endothelial dysfunction and the activity of repair enzymes in cardiac tissue from a pig model of early atherosclerosis. The study was conducted on 28 female Polish Landrace pigs, weighing 40 kg (approximately 3.5 months old), which were divided into three groups. The control group (n = 11) was fed a standard, commercial, balanced diet (BDG) for 12 months. The second group (n = 9) was fed an unbalanced, high-calorie Western-type diet (UDG). The third group (n = 8) was fed a Western-type diet for nine months and then switched to a standard, balanced diet (regression group, RG). Control examinations, including blood and urine sampling, were conducted every three months under identical conditions with food restriction for 12 h and water restriction for four hours before general anesthesia. The study analyzed markers of oxidative stress formed during lipid peroxidation processes, including etheno DNA adducts, ADMA, and NEFA. These markers play a crucial role in reactive oxygen species analysis in ischemia-reperfusion and atherosclerosis in mammalian tissue. Essential genes involved in oxidative-stress-induced DNA demethylation like OGG1 (8-oxoguanine DNA glycosylase), MPG (N-Methylpurine DNA Glycosylase), TDG (Thymine-DNA glycosylase), APEX (apurinic/apirymidinic endodeoxyribonuclease 1), PTGS2 (prostaglandin-endoperoxide synthase 2), and ALOX (Arachidonate Lipoxygenase) were measured using the Real-Time RT-PCR method. The data suggest that high oxidative stress, as indicated by TBARS levels, is associated with high levels of DNA repair enzymes and depends on the expression of genes involved in the repair pathway. In all analyzed groups of heart tissue homogenates, the highest enzyme activity and gene expression values were observed for the OGG1 protein recognizing the modified 8oxoG. Conclusion: With the long-term use of an unbalanced diet, the levels of all DNA repair genes are increased, especially (significantly) Apex, Alox, and Ptgs, which strongly supports the hypothesis that an unbalanced diet induces oxidative stress that deregulates DNA repair mechanisms and may contribute to genome instability and tissue damage.

Improvement of astrocytic gap junction involves the anti-depressive effect of celecoxib through inhibition of NF-κB

CONTEXT

Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, has been shown to exhibit anti-depressive effects in clinical trials. However, the direct mechanism underlying its effect on neuroinflammation remains unclear. Neuroinflammatory reaction from astrocytes leads to depression, and our previous study found that gap junction disorder between astrocytes aggravated neuroinflammatory reaction in depressed mice.

OBJECTIVE

To investigate the potential mechanism of celecoxib's effects on astrocytic gap junctions during the central nervous inflammation-induced depression.

MATERIALS & METHODS

Stereotaxic injection of lipopolysaccharide (LPS) into the prefrontal cortex (PFC) to establish a model of major depressive disorder (MDD). Celecoxib was administrated into PFC 15 min after LPS injection. The depressive performance was tested by tail suspension test and forced swimming test, and the levels of proinflammation cytokines were determined at mRNA and protein levels. Resting-state functional connection (rsFC) was employed to assess changes in the default mode network (DMN). Additionally, astrocytic gap junctions were also determined by lucifer yellow (LY) diffusion and transmission electron microscope (TEM), and the expression of connexin 43 (Cx43) was measured by western blotting, quantitative polymerase chain reaction, and immunofluorescence.

RESULTS

LPS injection induced significant depressive performance, which was ameliorated by celecoxib treatment. Celecoxib also improved rsFC in the DMN. Furthermore, celecoxib improved astrocytic gap junctions as evidenced by increased LY diffusion, shortened gap junction width, and normalized levels of phosphorylated Cx43. Celecoxib also blocked the phosphorylation of p65, and inhibition of p65 abolished the improvement of Cx43.

DISCUSSION & CONCLUSION

Anti-depressive effects of celecoxib are mediated, at least in part, by the inhibition of nuclear factor- kappa B (NF-κB) and the subsequent improvement of astrocytic gap junction function.

Inflammation, brain connectivity, and neuromodulation in post-traumatic headache

Post-traumatic headache (PTH) is a debilitating condition that affects individuals with different levels of traumatic brain injury (TBI) severity. The difficulties in developing an effective treatment are related to a lack of understanding the complicated mechanisms and neurobiological changes in brain function after a brain injury. Preclinical studies have indicated that peripheral and central sensitization of the trigeminal nociceptive pathways contributes to PTH. While recent brain imaging studies have uncovered widespread changes in brain functional connectivity following trauma, understanding exactly how these networks contribute to PTH after injury remains unknown. Stimulation of peripheral (trigeminal or vagus) nerves show promising efficacies in PTH experimental animals, likely mediated by influencing TBI-induced pathological plasticity by decreasing neuroinflammation and neuronal apoptosis. Non-invasive brain stimulations, such as transcranial magnetic or direct current stimulations, show analgesia for multiple chronic pain conditions, including PTH. Better mechanistic understanding of analgesia achieved by neuromodulations can define peripheral and central mechanisms involved in the development, the resolution, and the management of PTH.

Mechanisms and structure-activity relationships of polysaccharides in the intervention of Alzheimer's disease: A review

Alzheimer's disease (AD) is a complex neurodegenerative disease. Despite several decades of research, the development of effective treatments and responses for Alzheimer's disease remains elusive. The utilization of polysaccharides for Alzheimer's disease became more popular due to their beneficial characteristics, notably their multi-target activity and low toxicity. This review mainly focuses on the researches of recent 5 years in the regulation of AD by naturally derived polysaccharides, systematically lists the possible intervention pathways of polysaccharides from different mechanisms, and explores the structure-activity relationship between polysaccharide structural activities, so as to provide references for the intervention and treatment of AD by polysaccharides.

Celecoxib attenuates neuroinflammation, reactive astrogliosis and promotes neuroprotection in young rats with experimental hydrocephalus

Hydrocephalus is a neurological condition with altered cerebrospinal fluid flow (CSF). The treatment is surgical and the most commonly used procedure is ventricle-peritoneal shunt. However, not all patients can undergo immediate surgery or achieve complete lesion reversal. Neuroprotective measures are valuable in such cases. It was evaluated whether the use of celecoxib, a selective inhibitor of COX-2, associated or not with ventricular-subcutaneous derivation, could offer benefits to the brain structures affected by experimental hydrocephalus. Seven-day-old male Wistar Hannover rats induced by intracisternal injection of kaolin 15% were used, divided into five groups with ten animals each: intact control (C), untreated hydrocephalus (H), hydrocephalus treated with celecoxib 20 mg/kg intraperitoneal (HTC), hydrocephalus treated with shunt (HTS) and hydrocephalus treated with shunt and celecoxib 20 mg/kg intraperitoneal (HTCS). Celecoxib was administered for 21 consecutive days, starting the day after hydrocephalus induction and continuing until the end of the experimental period. The surgery was performed seven days after inducing hydrocephalus. Multiple assessment methods were used, such as behavioral tests (water maze and open field), histological analysis (hematoxylin and eosin), immunohistochemistry (caspase-3, COX-2, and GFAP), and ELISA analysis of GFAP. The results of the behavioral and memory tests indicated that celecoxib improves the neurobehavioral response. The improvement can be attributed to the reduced neuroinflammation (p < 0.05), and astrogliosis (p < 0.05) in different brain regions. In conclusion, the results suggest that celecoxib holds great potential as an adjuvant neuroprotective drug for the treatment of experimental hydrocephalus.

Infection, Inflammation, and Immunity in Sepsis

Sepsis is triggered by microbial infection, injury, or even major surgery. Both innate and adaptive immune systems are involved in its pathogenesis. Cytoplasmic presence of DNA or RNA of the invading organisms or damaged nuclear material (in the form of micronucleus in the cytoplasm) in the host cell need to be eliminated by various nucleases; failure to do so leads to the triggering of inflammation by the cellular cGAS-STING system, which induces the release of IL-6, TNF-α, and IFNs. These cytokines activate phospholipase A2 (PLA2), leading to the release of polyunsaturated fatty acids (PUFAs), gamma-linolenic acid (GLA), arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), which form precursors to various pro- and anti-inflammatory eicosanoids. On the other hand, corticosteroids inhibit PLA2 activity and, thus, suppress the release of GLA, AA, EPA, and DHA. PUFAs and their metabolites have a negative regulatory action on the cGAS-STING pathway and, thus, suppress the inflammatory process and initiate inflammation resolution. Pro-inflammatory cytokines and corticosteroids (corticosteroids > IL-6, TNF-α) suppress desaturases, which results in decreased formation of GLA, AA, and other PUFAs from the dietary essential fatty acids (EFAs). A deficiency of GLA, AA, EPA, and DHA results in decreased production of anti-inflammatory eicosanoids and failure to suppress the cGAS-STING system. This results in the continuation of the inflammatory process. Thus, altered concentrations of PUFAs and their metabolites, and failure to suppress the cGAS-STING system at an appropriate time, leads to the onset of sepsis. Similar abnormalities are also seen in radiation-induced inflammation. These results imply that timely administration of GLA, AA, EPA, and DHA, in combination with corticosteroids and anti-IL-6 and anti-TNF-α antibodies, may be of benefit in mitigating radiation-induced damage and sepsis.

Biosynthesized Selenium Nanoparticles Using Epigallocatechin Gallate Protect against Pentylenetetrazole-Induced Acute Epileptic Seizures in Mice via Antioxidative, Anti-Inflammatory, and Anti-Apoptotic Activities

Several negative outcomes are associated with current anti-epileptic medications. Epigallocatechin gallate (EGCG) is a plant-derived compound called catechin and has many medicinal activities, such as anti-inflammatory and antioxidant activities. Biosynthesized selenium nanoparticles are also showing their neuroprotective effect. The anti-epileptic effect of EGCG, alone or with SeNPs, is still debated. Here, we aimed to investigate the potential anti-seizure effect of biosynthesized SeNPs using EGCG (EGCG-SeNPs) against epileptic seizures and hippocampal damage, which is enhanced by pentylenetetrazole (PTZ) injection in mice. Mice were grouped as follows: control; PTZ-exposed group (epileptic model); EGCG + PTZ-treated group; sodium selenite (Na₂SeO₃) + PTZ-treated group; EGCG-SeNPs + PTZ-treated group; and valproic acid (VPA) + PTZ-treated group. EGCG-SeNPs administration showed anti-epileptic activity by increasing the latency time and reducing the seizure duration following the PTZ injection. Additionally, EGCG-SeNPs counteracted the PTZ-induced changes in oxidants and antioxidants. Moreover, EGCG-SeNPs inhibited the inflammatory response by suppressing the release of pro-inflammatory cytokines and decreasing the immunoreactivity of the glial fibrillary acidic protein and mRNA expression of glutamate receptor subunit zeta-1 (NMDAR; Grin1), showing their inhibitory effect on epilepsy-associated inflammation. Moreover, EGCG-SeNPs reduced PTZ-induced neuronal apoptosis, as indicated by a reduction in the levels of pro-apoptotic proteins and an elevation of the anti-apoptotic protein. Moreover, EGCG-SeNPs administration significantly modulated the PTZ-induced changes in monoamine levels and acetylcholinesterase activity in the hippocampal tissue. The obtained findings suggest the anti-seizure activity of EGCG-SeNPs via their antioxidant, anti-inflammatory, and anti-apoptotic effects, along with their neuromodulatory effect.

The impact of lipid A modification on biofilm and related pathophysiological phenotypes, endotoxicity, immunogenicity, and protection of Salmonella Typhimurium

This study presents the engineering of a less endotoxic Salmonella Typhimurium strain by manipulating the lipid-A structure of the lipopolysaccharide (LPS) component. Salmonella lipid A was dephosphorylated by using lpxE from Francisella tularensis. The 1-phosphate group from lipid-A was removed selectively, resulting in a close analog of monophosphoryl lipid A. We observed a significant impact of ∆pagL on major virulence factors such as biofilm formation, motility, persistency, and immune evasion. In correlation with biofilm and motility retardation, adhesion and invasion were elevated but with reduced intracellular survival, a favorable phenotype prospect of a vaccine strain. Western blotting and silver staining confirmed the absence of the O-antigen and truncated lipid-A core in the detoxified Salmonella mutant. In vitro and in vivo studies demonstrated that the dephosphorylated Salmonella mutant mediated lower pro-inflammatory cytokine secretion than the wild-type strain. The vaccine strains were present in the spleen and liver for five days and were cleared from the organs by day seven. However, the wild-type strain persisted in the spleen, liver, and brain, leading to sepsis-induced death. Histological evaluations of tissue samples further confirmed the reduced endotoxic activity of the detoxified Salmonella mutant. The detoxification strategy did not compromise the level of protective immunity, as the vaccine strain could enhance humoral and cellular immune responses and protect against the wild-type challenge in immunized mice.

COX Isozymes and Non-Uniform Neoangiogenesis: What is their role in Endometriosis?

This literature review compared the efficacy in of NSAIDs with a placebo in pain relief and disease regression of endometriosis. Despite the poor evidence found, the results showed that NSAIDs were more effective in pain relief with regressive effects on the endometriotic lesions compared to placebo. We postulate herein that COX-2 is chiefly responsible for pain whilst COX-1 is responsible mainly for the establishment of endometriotic lesions. Hence, there must be a temporal difference in the activation of the two isozymes. We differentiated between two pathways in the conversion of arachidonic acid to prostaglandins by the COX isozymes referred to as 'direct' and indirect', supporting our initial theory. Finally, we postulate that there are two stages of neoangiogenesis in the formation of endometriotic lesions; 'founding' that first establishes blood supply and 'maintenance' that upkeeps it This is fertile ground for further research in a niche that needs more literature. Its aspects may be diversely explored. The theories we propose offer information for a more targeted treatment of endometriosis.

The Effects of Neuropeptide B on Proliferation and Differentiation of Porcine White Preadipocytes into Mature Adipocytes

Neuropeptide B (NPB) affects energy homeostasis and metabolism by binding and activating NPBWR1 and NPBWR2 in humans and pigs. Recently, we reported that NPB promotes the adipogenesis of rat white and brown preadipocytes as well as 3T3-L1 cells. In the present study, we evaluated the effects of NPB on the proliferation and differentiation of white porcine preadipocytes into mature adipocytes. We identified the presence of NPB, NPBWR1, and NPBWR2 on the mRNA and protein levels in porcine white preadipocytes. During the differentiation process, NPB increased the mRNA expression of PPARγ, C/EBPβ, C/EBPα, PPARγ, and C/EBPβ protein production in porcine preadipocytes. Furthermore, NPB stimulated lipid accumulation in porcine preadipocytes. Moreover, NPB promoted the phosphorylation of the p38 kinase in porcine preadipocytes, but failed to induce ERK1/2 phosphorylation. NPB failed to stimulate the expression of C/EBPβ in the presence of the p38 inhibitor. Taken together, we report that NPB promotes the differentiation of porcine preadipocytes via a p38-dependent mechanism.

Environmental Enrichment Protects against Neurotoxic Effects of Lipopolysaccharide: A Comprehensive Overview

Neuroinflammation is a pathophysiological condition associated with damage to the nervous system. Maternal immune activation and early immune activation have adverse effects on the development of the nervous system and cognitive functions. Neuroinflammation during adulthood leads to neurodegenerative diseases. Lipopolysaccharide (LPS) is used in preclinical research to mimic neurotoxic effects leading to systemic inflammation. Environmental enrichment (EE) has been reported to cause a wide range of beneficial changes in the brain. Based on the above, the purpose of the present review is to describe the effects of exposure to EE paradigms in counteracting LPS-induced neuroinflammation throughout the lifespan. Up to October 2022, a methodical search of studies in the literature, using the PubMed and Scopus databases, was performed, focusing on exposure to LPS, as an inflammatory mediator, and to EE paradigms in preclinical murine models. On the basis of the inclusion criteria, 22 articles were considered and analyzed in the present review. EE exerts sex- and age-dependent neuroprotective and therapeutic effects in animals exposed to the neurotoxic action of LPS. EE’s beneficial effects are present throughout the various ages of life. A healthy lifestyle and stimulating environments are essential to counteract the damages induced by neurotoxic exposure to LPS.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Inhibition of cyclooxygenase and EP3 receptor improved long term potentiation in a rat organotypic hippocampal model of repeated blast traumatic brain injury

Blast-induced traumatic brain injury (bTBI) is a health concern in military service members who are exposed to multiple blasts throughout their training and deployment. Our group has previously reported decreased long term potentiation (LTP) following repeated bTBI in a rat organotypic hippocampal slice culture (OHSC) model. In this study, we investigated changes in inflammatory markers like cyclooxygenase (COX) and tested the efficacy of COX or prostaglandin EP3 receptor (EP3R) inhibitors in attenuating LTP deficits. Expression of COX-2 was increased 48 h following repeated injury, whereas COX-1 expression was unchanged. EP3R expression was upregulated, and cyclic adenosine monophosphate (cAMP) concentration was decreased after repeated blast exposure. Post-traumatic LTP deficits improved after treatment with a COX-1 specific inhibitor, SC-560, a COX-2 specific inhibitor, rofecoxib, a pan-COX inhibitor, ibuprofen, or an EP3R inhibitor, L-798,106. Delayed treatment with ibuprofen and L-798,106 also prevented LTP deficits. These findings suggest that bTBI induced neuroinflammation may be responsible for some functional deficits that we have observed in injured OHSCs. Additionally, COX and EP3R inhibition may be viable therapeutic strategies to reduce neurophysiological deficits after repeated bTBI.

LDL-Dependent Regulation of TNFα/PGE2 Induced COX-2/mPGES-1 Expression in Human Macrophage Cell Lines

Inflammation is a hallmark in severe diseases such as atherosclerosis and non-alcohol-induced steatohepatitis (NASH). In the development of inflammation, prostaglandins, especially prostaglandin E₂ (PGE₂), are major players alongside with chemo- and cytokines, like tumor-necrosis-factor alpha (TNFα) and interleukin-1 beta (IL-1β). During inflammation, PGE₂ synthesis can be increased by the transcriptional induction of the two key enzymes: cyclooxygenase 2 (COX-2), which converts arachidonic acid to PGH₂, and microsomal prostaglandin E2 synthase 1 (mPGES-1), which synthesizes PGE₂ from PGH₂. Both COX-2 and mPGES-2 were induced by a dietary intervention where mice were fed a fatty acid-rich and, more importantly, cholesterol-rich diet, leading to the development of NASH. Since macrophages are the main source of PGE₂ synthesis and cholesterol is predominantly transported as LDL, the regulation of COX-2 and mPGES-1 expression by native LDL was analyzed in human macrophage cell lines. THP-1 and U937 monocytes were differentiated into macrophages, through which TNFα and PGE-2 induced COX-2 and mPGES-1 expression by LDL could be analyzed on both mRNA and protein levels. In addition, the interaction of LDL- and EP receptor signal chains in COX-2/mPGES-1 expression and PGE₂-synthesis were analyzed in more detail using EP receptor specific agonists. Furthermore, the LDL-mediated signal transduction in THP-1 macrophages was analyzed by measuring ERK and Akt phosphorylation as well as transcriptional regulation of transcription factor Egr-1. COX-2 and mPGES-1 were induced in both THP-1 and U937 macrophages by the combination of TNFα and PGE₂. Surprisingly, LDL dose-dependently increased the expression of mPGES-1 but repressed the expression of COX-2 on mRNA and protein levels in both cell lines. The interaction of LDL and PGE₂ signal chains in mPGES-1 induction as well as PGE₂-synthesis could be mimicked by through simultaneous stimulation with EP2 and EP4 agonists. In THP-1 macrophages, LDL induced Akt-phosphorylation, which could be blocked by a PI3 kinase inhibitor. Alongside blocking Akt-phosphorylation, the PI3K inhibitor inhibited LDL-mediated mPGES-1 induction; however, it did not attenuate the repression of COX-2 expression. LDL repressed basal ERK phosphorylation and expression of downstream transcription factor Egr-1, which might lead to inhibition of COX-2 expression. These findings suggest that simultaneous stimulation with a combination of TNFα, PGE₂, and native LDL-activated signal chains in macrophage cell lines leads to maximal mPGES-1 activity, as well repression of COX-2 expression, by activating PI3K as well as repression of ERK/Egr-1 signal chains.

Environmental exposure to non-steroidal anti-inflammatory drugs and potential contribution to eggshell thinning in birds

Abnormally thin eggshells can reduce avian reproductive success, and have caused rapid population declines. The best known examples of this phenomenon are the widespread population crashes in birds, mostly raptors, fish eating birds, and scavengers, caused by the pesticide DDT and its isomers in the 1960s. A variety of other chemicals have been reported to cause eggshell thinning. Non-steroidal anti-inflammatory drugs (NSAIDs), which are extensively and increasingly used in human and veterinary medicine, may be one particularly concerning group of chemicals that demonstrate an ability to impair eggshell development, based both on laboratory studies and on their known mechanism of action. In this review, we outline environmental and wildlife exposure to NSAIDs, describe the process of eggshell formation, and discuss pathways affected by NSAIDs. We list pharmaceuticals, including NSAIDs, and other compounds demonstrated to reduce eggshell thickness, and highlight their main mechanisms of action. Dosing studies empirically demonstrated that NSAIDs reduce eggshell thickness through cyclooxygenase inhibition, which suppresses prostaglandin synthesis and reduces the calcium available for the mineralization of eggshell. Using the US EPA's CompTox Chemicals Dashboard, we show that NSAIDs are predicted to strongly inhibit cyclooxygenases. NSAIDs have been observed both in the putative diet of scavenging birds, and we report examples of NSAIDs detected in eggs or tissues of wild and captive Old World vultures. We suggest that NSAIDs in the environment represent a hazard that could impair reproduction in wild birds.

Reactive Microgliosis in Sepsis-Associated and Acute Hepatic Encephalopathies: An Ultrastructural Study

Sepsis and acute liver failure are associated with severe endogenous intoxication. Microglia, which are the resident immune brain cells, play diverse roles in central nervous system development, surveillance, and defense, as well as contributing to neuroinflammatory reactions. In particular, microglia are fundamental to the pathophysiology of reactive toxic encephalopathies. We analyzed microglial ultrastructure, morphotypes, and phagocytosis in the sensorimotor cortex of cecal ligation and puncture (CLP) and acetaminophen-induced liver failure (AILF) Wistar rats. A CLP model induced a gradual shift of ~50% of surveillant microglia to amoeboid hypertrophic-like and gitter cell-like reactive phenotypes with active phagocytosis and frequent contacts with damaged neurons. In contrast, AILF microglia exhibited amoeboid, rod-like, and hypertrophic-like reactive morphotypes with minimal indications for efficient phagocytosis, and were mostly in contact with edematous astrocytes. Close interactions of reactive microglia with neurons, astrocytes, and blood-brain barrier components reflect an active contribution of these cells to the tissue adaptation and cellular remodeling to toxic brain damage. Partial disability of reactive microglia may affect the integrity and metabolism in all tissue compartments, leading to failure of the compensatory mechanisms in acute endogenous toxic encephalopathies.

Application of ionic liquid to enhance the nose-to-brain delivery of etodolac

The purpose of this study was to enhance the delivery of Etodolac (ETD) to the brain through intranasal administration using an ionic liquid (IL) consisting of ETD and proline ethyl ester. The IL of ETD was prepared by mixing ETD with proline ethyl ester as a counterion in a molar ratio of 1:2.The formation of the IL was confirmed by differential scanning calorimetry (DSC), infrared spectroscopy (IR) and proton nuclear magnetic resonance (¹H-NMR).The solubility of ETD in simulated nasal fluids was improved by approximately 200-fold due to the formation of IL. The intranasal administration of ETD-containing IL, which is viscous, increased the nose-to-brain delivery by approximately 7-fold 30 min after an administration of the ETD solution alone. The enhancement of ETD delivery to the brain from the nose was attributed to the enhanced retention of ETD in the nasal mucosal surface due to the viscosity of IL. The induction of prostaglandin E2 in the brain inflammation that was induced by lipopolysaccharides was significantly suppressed by up to 40% in the IL-treated group compared with the drug-untreated group. Therefore, ETD-containing IL were suggested to be useful in designing intranasal formulations for the nasal delivery of ETDs to the brain.

Lipid-Based Molecules on Signaling Pathways in Autism Spectrum Disorder

The signaling pathways associated with lipid metabolism contribute to the pathophysiology of autism spectrum disorder (ASD) and provide insights for devising new therapeutic strategies. Prostaglandin E2 is a membrane-derived lipid molecule that contributes to developing ASD associated with canonical Wnt signaling. Cyclooxygenase-2 plays a key role in neuroinflammation and is implicated in the pathogenesis of neurodevelopmental diseases, such as ASD. The endocannabinoid system maintains a balance between inflammatory and redox status and synaptic plasticity and is a potential target for ASD pathophysiology. Redox signaling refers to specific and usually reversible oxidation–reduction reactions, some of which are also involved in pathways accounting for the abnormal behavior observed in ASD. Redox signaling and redox status-sensitive transcription factors contribute to the pathophysiology of ASD. Cannabinoids regulate the redox balance by altering the levels and activity of antioxidant molecules via ROS-producing NADPH oxidase (NOX) and ROS-scavenging superoxide dismutase enzymes. These signaling cascades integrate a broad range of neurodevelopmental processes that may be involved in the pathophysiology of ASD. Based on these pathways, we highlight putative targets that may be used for devising novel therapeutic interventions for ASD.

Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation?

As inflammation in the brain contributes to several neurological and psychiatric diseases, the cause of neuroinflammation is being widely studied. The causes of neuroinflammation can be roughly divided into the following domains: viral infection, autoimmune disease, inflammation from peripheral organs, mental stress, metabolic disorders, and lifestyle. In particular, the effects of neuroinflammation caused by inflammation of peripheral organs have yet unclear mechanisms. Many diseases, such as gastrointestinal inflammation, chronic obstructive pulmonary disease, rheumatoid arthritis, dermatitis, chronic fatigue syndrome, or myalgic encephalomyelitis (CFS/ME), trigger neuroinflammation through several pathways. The mechanisms of action for peripheral inflammation-induced neuroinflammation include disruption of the blood-brain barrier, activation of glial cells associated with systemic immune activation, and effects on autonomic nerves via the organ-brain axis. In this review, we consider previous studies on the relationship between systemic inflammation and neuroinflammation, focusing on the brain regions susceptible to inflammation.

Clinical Assessment of Neuroinflammatory Markers and Antioxidants in Neonates with Hyperbilirubinemia and Their Association with Acute Bilirubin Encephalopathy

Objective: To assess the oxidant and antioxidant status in neonates with and without hyperbilirubinemia and their association with early manifestations of acute bilirubin encephalopathy (ABE), in addition to eliciting the possible oxidative effects of phototherapy. Methods: This prospective observational study was conducted with 104 full-term newborns at Menoufia University Hospitals from January 2020 to January 2021 to help resolve the debate regarding whether bilirubin is an antioxidant. The cases group (Group I) included 52 full-term newborns (37−40 weeks) with hyperbilirubinemia during the neonatal period, while the control group (Group II) included 52 healthy, full-term age and sex-matched newborns who did not have hyperbilirubinemia. The cases group was further subdivided into Group Ia (n = 12), which included newborns who presented with neurological manifestations suggesting early ABE, and Group Ib (n = 40), which included newborns with no signs suggestive of ABE. All newborns were subjected to clinical and neurological examinations, as well as laboratory investigations. Results: Comparing the specific biological markers between the Group 1 subgroups before phototherapy, the mean plasma levels of prostaglandin-Em, prostaglandin E2, and TSB were significantly higher in Subgroup I(a) (all p < 0.05). After phototherapy, Subgroup I(a) patients had significantly higher levels of prostaglandin-Em, DSB, and TSB (p < 0.05). The biological marker levels improved after phototherapy in terms of TAC (0.811 vs. 0.903), MDA (8.18 vs. 5.13), prostaglandin-Em (37.47 vs. 27.23), prostaglandin E2 (81.09 vs. 31.49), DSB (1.21 vs. 0.55), and TSB (16.63 vs. 8.26; p-value < 0.05). Conclusion: Our study showed that an elevated level of serum bilirubin increases oxidative stress and decreases antioxidant capacity. The reduction in bilirubin levels by phototherapy is associated with a decrease in oxidative stress markers (MDA, PGEm, and PGE2) and an upsurge in TAC, highlighting the absence of oxidative stress effects arising from phototherapy. Neonates with neurological manifestations suggesting ABE had higher levels of oxidative stress markers and lower levels of total antioxidant capacity than those without.

Neuroinflammation, Sleep, and Circadian Rhythms

Molecules involved in innate immunity affect sleep and circadian oscillators and vice versa. Sleep-inducing inflammatory molecules are activated by increased waking activity and pathogens. Pathologies that alter inflammatory molecules, such as traumatic brain injury, cancer, cardiovascular disease, and stroke often are associated with disturbed sleep and electroencephalogram power spectra. Moreover, sleep disorders, such as insomnia and sleep disordered breathing, are associated with increased dysregulation of inflammatory processes. Inflammatory molecules in both the central nervous system and periphery can alter sleep. Inflammation can also modulate cerebral vascular hemodynamics which is associated with alterations in electroencephalogram power spectra. However, further research is needed to determine the interactions of sleep regulatory inflammatory molecules and circadian clocks. The purpose of this review is to: 1) describe the role of the inflammatory cytokines interleukin-1 beta and tumor necrosis factor-alpha and nucleotide-binding domain and leucine-rich repeat protein-3 inflammasomes in sleep regulation, 2) to discuss the relationship between the vagus nerve in translating inflammatory signals between the periphery and central nervous system to alter sleep, and 3) to present information about the relationship between cerebral vascular hemodynamics and the electroencephalogram during sleep.

Combined royal jelly 10-hydroxydecanoic acid and aspirin has a synergistic effect against memory deficit and neuroinflammation

Alzheimer's disease (AD), the most common form of neurodegenerative dementia among the older population, is associated with acute or chronic inflammation. As a nonsteroidal anti-inflammatory drug, aspirin has recently been widely studied in the prevention and treatment of neurodegenerative diseases. However, there is a controversy about the efficacy as well as the adverse effects of aspirin. 10-Hydroxydecanoic acid (10-HDAA) is a characteristic fatty acid found in the honey bee product royal jelly. In this study, we found that 10-HDAA attenuated the activation of the NF-κB pathway, then targeted Ptgs-1/2, the well-known target of aspirin. Hence, combined therapy of 10-HDAA and aspirin was conducted. In vitro assays suggested that this combinatory group alleviated LPS-induced inflammation in BV-2 cells, as assessed by the downregulation of nitric oxide, COX-2, and IL-6 compared to 10-HDAA or aspirin treatment alone. In vivo assays showed that the combined treatment synergistically inhibited the overactivation of glial cells and decreased the levels of pro-inflammatory mediators. Moreover, 10-HDAA alleviated the adverse effects of aspirin on gastrointestinal injuries and microbiota dysbiosis. The Morris water maze test indicated that neither 10-HDAA nor aspirin effectively improved LPS-induced memory dysfunction, but the combined therapy showed synergistic effects. Altogether, our findings support 10-HDAA and aspirin combinatory therapy as the basis for future therapeutics for AD and other neuroinflammation-related diseases with minimal adverse effects.

Macroalgal Proteins: A Review

Population growth is the driving change in the search for new, alternative sources of protein. Macroalgae (otherwise known as seaweeds) do not compete with other food sources for space and resources as they can be sustainably cultivated without the need for arable land. Macroalgae are significantly rich in protein and amino acid content compared to other plant-derived proteins. Herein, physical and chemical protein extraction methods as well as novel techniques including enzyme hydrolysis, microwave-assisted extraction and ultrasound sonication are discussed as strategies for protein extraction with this resource. The generation of high-value, economically important ingredients such as bioactive peptides is explored as well as the application of macroalgal proteins in human foods and animal feed. These bioactive peptides that have been shown to inhibit enzymes such as renin, angiotensin-I-converting enzyme (ACE-1), cyclooxygenases (COX), α-amylase and α-glucosidase associated with hypertensive, diabetic, and inflammation-related activities are explored. This paper discusses the significant uses of seaweeds, which range from utilising their anthelmintic and anti-methane properties in feed additives, to food techno-functional ingredients in the formulation of human foods such as ice creams, to utilising their health beneficial ingredients to reduce high blood pressure and prevent inflammation. This information was collated following a review of 206 publications on the use of seaweeds as foods and feeds and processing methods to extract seaweed proteins.

Astroglial CB1 Cannabinoid Receptors Mediate CP 55,940-Induced Conditioned Place Aversion Through Cyclooxygenase-2 Signaling in Mice

Cannabinoids (CBs), such as phytocannabinoids, synthetic CBs, and endogenous CBs, can be neuroprotective, rewarding, or aversive. The aversive effects of CBs may hinder their medical and recreational applications. It is unknown which type of CB receptors mediates the direct aversive effects of synthetic CB CP 55,940 which is an analog of Δ⁹-tetrahydrocannabinol, the major psychoactive component of marijuana. In this study, we address this question by taking the advantage of systematic type 1 CB receptor (CB1R) knockout mice and conditional reinstatement of this receptor only in astrocytes. We show that CP 55,940 at a concentration of 1 mg/kg induces conditioned place aversion (CPA) and the CPA effect of CP 55,940 is mediated by the astroglial CB1Rs. Inhibiting cyclooxygenase-2 (COX-2) eliminates CP 55,940-induced CPA in mice that only express CB1Rs in astrocytes. These findings conclude that CPA effect of CP 55,940 is mediated by the astroglial CB1Rs through COX-2 signaling, suggesting that selective COX-2 inhibition or precise isolation of astroglial CB1R activity may be the strategy for treating aversive response of medical and recreational administrations of marijuana.

Research Progress on the Role of Inflammatory Mechanisms in the Development of Postoperative Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD), as one of the common postoperative complications, mainly occurs after surgery and anesthesia, especially in the elderly. It refers to cognitive function changes such as decreased learning and memory ability and inability to concentrate. In severe cases, there could be personality changes and a decline in social behavior. At present, a great deal of research had been carried out on POCD, but its specific mechanism remains unclear. The release of peripheral inflammation-related factors, the degradation and destruction of the blood-brain barrier, the occurrence of central inflammation, and the neuronal apoptosis and synaptic loss could be promoted by neuroinflammation indicating that inflammatory mechanisms may play key roles in the occurrence of POCD.

Curcumin improves memory deficits by inhibiting HMGB1-RAGE/TLR4-NF-κB signalling pathway in APPswe/PS1dE9 transgenic mice hippocampus

Amyloid‐β (Aβ) deposition in the brain has been implicated in the development of Alzheimer's disease (AD), and neuroinflammation generates AD progression. Therapeutic effects of anti‐inflammatory approaches in AD are still under investigation. Curcumin, a potent anti‐inflammatory and antioxidant, has demonstrated therapeutic potential in AD models. However, curcumin's anti‐inflammatory molecular mechanisms and its associated cognitive impairment mechanisms in AD remain unclear. The high‐mobility group box‐1 protein (HMGB1) participates in the regulation of neuroinflammation. Herein, we attempted to evaluate the anti‐inflammatory effects of chronic oral administration of curcumin and HMGB1 expression in APP/PS1 transgenic mice AD model. We found that transgenic mice treated with a curcumin diet had shorter escape latencies and showed a significant increase in percent alternation, when compared with transgenic mice, in the Morris water maze and Y‐maze tests. Additionally, curcumin treatment could effectively decrease HMGB1 protein expression, advanced glycosylation end product‐specific receptor (RAGE), Toll‐like receptors‐4 (TLR4) and nuclear factor kappa B (NF‐κB) in transgenic mice hippocampus. However, amyloid plaques detected with thioflavin‐S staining in transgenic mice hippocampus were not affected by curcumin treatment. In contrast, curcumin significantly decreased GFAP‐positive cells, as assessed by immunofluorescence staining. Taken together, these data indicate that oral administration of curcumin may be a promising agent to attenuate memory deterioration in AD mice, probably inhibiting the HMGB1‐RAGE/TLR4‐NF‐κB inflammatory signalling pathway.

Peroxisome Proliferator-Activated Receptor-Gamma (PPAR-ɣ): Molecular Effects and Its Importance as a Novel Therapeutic Target for Cerebral Ischemic Injury

Cerebral ischemic injury is a leading cause of death and long-term disability throughout the world. Peroxisome proliferator-activated receptor gamma (PPAR-ɣ) is a ligand-activated nuclear transcription factor that is a member of the PPAR family. PPAR-ɣ has been shown in several in vitro and in vivo models to prevent post-ischemic inflammation and neuronal damage by negatively controlling the expression of genes modulated by cerebral ischemic injury, indicating a neuroprotective effect during cerebral ischemic injury. A extensive literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out to understand the nature of the extensive work done on the mechanistic role of Peroxisome proliferator activated receptor gamma and its modulation in Cerebral ischemic injury. PPAR-ɣ can interact with specific DNA response elements to control gene transcription and expression when triggered by its ligand. It regulates lipid metabolism, improves insulin sensitivity, modulates antitumor mechanisms, reduces oxidative stress, and inhibits inflammation. This review article provides insights on the current state of research into the neuroprotective effects of PPAR-ɣ in cerebral ischemic injury, as well as the cellular and molecular mechanisms by which these effects are modulated, such as inhibition of inflammation, reduction of oxidative stress, suppression of pro-apoptotic production, modulation of transcription factors, and restoration of injured tissue through neurogenesis and angiogenesis.

Hepatic COX-2 expression protects mice from an alcohol-high fat diet-induced metabolic disorder by involving protein acetylation related energy metabolism

PURPOSE

A diet high in fat and ethanol often results in chronic metabolic disorder, hepatic steatosis, and liver inflammation. Constitutive hepatic cyclooxygenase-2 (COX-2) expression could protect from high fat-induced metabolism disturbance in a murine model. In this study, we explored the influence of hCOX-2 transgenic [TG] to high fat with ethanol-induced metabolic disorder and liver injury using a mouse animal model.

METHODS

12-week-old male hepatic hCOX-2 transgenic (TG) or wild type mice (WT) were fed either a high fat and ethanol liquid diet (HF+Eth) or a regular control diet (RCD) for 5 weeks (four groups: RCD/WT, RCD/TG; HF+Eth/TG, HF+Eth/WT). We assessed metabolic biomarkers, cytokine profiles, histomorphology, and gene expression to study the impact of persistent hepatic COX-2 expression on diet-induced liver injury.

RESULTS

In the HF+Eth diet, constitutively hepatic human COX-2 expression protects mice from body weight gain and white adipose tissue accumulation, accompanied by improved IPGTT response, serum triglyceride/cholesterol levels, and lower levels of serum and liver inflammatory cytokines. Histologically, hCOX-2 mice showed decreased hepatic lipid droplets accumulation, decreased hepatocyte ballooning, and improved steatosis scores. Hepatic hCOX-2 overexpression enhanced AKT insulin signaling and increased fatty acid synthesis in both RCD and HF+Eth diet groups. The anti-lipogenic effect of hCOX-2 TG in the HF+Eth diet animals was mediated by increasing lipid disposal through enhanced β-oxidation via elevations in the expression of PPARα and PPARγ, and increased hepatic autophagy as assessed by the ratio of autophagy markers LC3 II/I in hepatic tissue. Various protein acetylation pathway components, including HAT, HDAC1, SIRT1, and SNAIL1, were modulated in hCOX-2 TG mice in either RCD or HF+Eth diet.

CONCLUSIONS

Hepatic human COX-2 expression protected mice from the metabolic disorder and liver injury induced by a high fat and ethanol diet by enhancing hepatic lipid expenditure. Epigenetic reprogramming of diverse metabolic genes might be involved in the anti-lipogenic effect of COX-2.

Involvement and relationship of bacterial lipopolysaccharides and cyclooxygenases levels in Alzheimer's Disease and Mild Cognitive Impairment patients

This study reports elevated levels of bacterial lipopolysaccharides (LPSs) and cyclooxygenases (COX-1/2) in blood serum and cerebrospinal fluid (CSF) of Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) patients compared to cognitively healthy individuals, indicating LPSs as promising biomarkers, especially in serum. LPSs, in both fluids, positively correlate with COX-1/2, Αβ₄₂ and tau and negatively with mental state. Furthermore, COX-2 is the main determinant of LPSs presence in serum, whereas COX-1 in CSF. These results underline the significance of microbial/ inflammatory involvement in dementia and offer novel perspectives on the roles of LPSs and COX in pathogenesis of AD.

RGS10 physically and functionally interacts with STIM2 and requires store-operated calcium entry to regulate pro-inflammatory gene expression in microglia

Chronic activation of microglia is a driving factor in the progression of neuroinflammatory diseases, and mechanisms that regulate microglial inflammatory signaling are potential targets for novel therapeutics. Regulator of G protein Signaling 10 is the most abundant RGS protein in microglia, where it suppresses inflammatory gene expression and reduces microglia-mediated neurotoxicity. In particular, microglial RGS10 downregulates the expression of pro-inflammatory mediators including cyclooxygenase 2 (COX-2) following stimulation with lipopolysaccharide (LPS). However, the mechanism by which RGS10 affects inflammatory signaling is unknown and is independent of its canonical G protein targeted mechanism. Here, we sought to identify non-canonical RGS10 interacting partners that mediate its anti-inflammatory mechanism. Through RGS10 co-immunoprecipitation coupled with mass spectrometry, we identified STIM2, an endoplasmic reticulum (ER) localized calcium sensor and a component of the store-operated calcium entry (SOCE) machinery, as a novel RGS10 interacting protein in microglia. Direct immunoprecipitation experiments confirmed RGS10-STIM2 interaction in multiple microglia and macrophage cell lines, as well as in primary cells, with no interaction observed with the homologue STIM1. We further determined that STIM2, Orai channels, and the calcium-dependent phosphatase calcineurin are essential for LPS-induced COX-2 production in microglia, and this pathway is required for the inhibitory effect of RGS10 on COX-2. Additionally, our data demonstrated that RGS10 suppresses SOCE triggered by ER calcium depletion and that ER calcium depletion, which induces SOCE, amplifies pro-inflammatory genes. In addition to COX-2, we also show that RGS10 suppresses the expression of pro-inflammatory cytokines in microglia in response to thrombin and LPS stimulation, and all of these effects require SOCE. Collectively, the physical and functional links between RGS10 and STIM2 suggest a complex regulatory network connecting RGS10, SOCE, and pro-inflammatory gene expression in microglia, with broad implications in the pathogenesis and treatment of chronic neuroinflammation.

Anti-inflammatory effects of rhaponticin on LPS-induced human endothelial cells through inhibition of MAPK/NF-κβ signaling pathways

The untreated systemic chronic inflammation leads to autoimmune diseases, hyperglycemia, cardiovascular diseases, type 2 diabetes, hypertension, osteoporosis, and so on. Phytochemicals effectively inhibit the inflammation, and numerous studies have proved that the phytocomponents possess anti-inflammatory property via inhibiting the cyclooxygenase and lipoxygenase signaling pathways. Rhaponticin is one such phytochemical obtained from the perennial plant Rheum rhaponticum L. belonging to Polygonaceae family. We assessed the anti-inflammatory potency of rhaponticin in endothelial cells induced with lipopolysaccharides (LPS). Four different endothelial cells induced with LPS were treated with rhaponticin and assessed for the nitric oxide generation. The cytotoxic potency of rhaponticin was evaluated in endothelial cells using the 3-(4,5-dimethylthizaol-2yl)-2,5-diphenyl tetrazolium bromide assay. The tumor necrosis factor-α (TNF-α) synthesis was quantified using the commercially available assay kit. The inflammatory signaling protein gene expression of TNF-α, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and interleukin-1β (IL-1β) was analyzed with quantitative polymerase chain reaction (PCR) analysis. The gene expression of NADPH oxidase (NOX) cytoplasmic catalytic subunits gp91^phox , p47^phox , and p22^phox was assessed with real-time PCR analysis. Finally, to confirm the anti-inflammatory potency of rhaponticin, the nuclear factor kappa B (NFκB) and mitogen-activated protein kinase (MAPK) signaling protein expression was analyzed with immunoblotting analysis. Rhaponticin treatment significantly decreased the levels of nitric oxide and TNF-α synthesis in LPS-induced endothelial cells. It significantly decreased the gene expression of inflammatory proteins and NOX signaling protein. The protein expression of NFκB and MAPK signaling proteins was drastically decreased in rhaponticin-treated endothelial cells induced with LPS. Overall, our results confirm that rhaponticin effectively inhibited the inflammation triggered by LPS in endothelial cells via downregulating iNOS, COX2, and NFκB and MAPK signaling pathways.

Role of prostaglandin E2 in allogeneic mesenchymal stem cell therapy for cardiac repair

Ischemic heart disease is among the primary causes of cardiovascular-related deaths worldwide. Conventional treatments including surgical interventions and medical therapies aid in preventing further damage to heart muscle but are unable to provide a permanent solution. In recent years, stem cell therapy has emerged as an attractive alternative to restore damaged myocardium after myocardial injury. Allogeneic (donor-derived) mesenchymal stem cells (MSCs) have shown great promise in preclinical and clinical studies, making them the most widely accepted candidates for cardiac cell therapy. MSCs promote cardiac repair by modulating host immune system and secreting various soluble factors, of which prostaglandin E2 (PGE2) is an important one. PGE2 plays a significant role in regulating cardiac remodeling following myocardial injury. In this review, we provide an overview of allogeneic MSCs as candidates for myocardial regeneration with a focus on the role of the PGE2/cyclooxygenase-2 (COX2) pathway in mediating these effects.

New insights into the obligatory nature of cyclooxygenase-2 and PGE2 during early chick embryogenesis

Temporal expression patterns and activity of two cyclooxygenase (COX-1 and COX-2) isoforms were analysed during early chick embryogenesis to evaluate their roles in development. COX-2 inhibition with etoricoxib resulted in significant structural anomalies such as anophthalmia (born without one or both eyes), phocomelia (underdeveloped or truncated limbs), and gastroschisis (an opening in the abdominal wall), indicating its significance in embryogenesis. Furthermore, the levels of PGE₂, PGD₂, PGF_2α, and TXB₂ were assessed using quantitative LC-MS/MS to identify which effector prostanoid (s) had their synthesis initiated by COX-2. COX-2 inhibition was only shown to reduce the level of PGE₂ significantly_, and hence it could be inferred that the later could be largely under the regulation of activated COX-2 in chick embryos. The compensatory increase in the activity of COX-1 observed in the etoricoxib-treated group helped to maintain the levels of PGD₂, PGF_2α, and TXB₂. Though the roles of these three prostanoids in embryogenesis need to be further clarified, it appears that their contribution to the observed developmental anomalies is minimal. This study has shown that COX-2 is functionally active during chick embryogenesis, and it plays a central role in the structural configuration of several organs and tissues through its downstream effector molecule PGE₂.

Risk Factors, Mechanisms and Treatments of Thromboangiitis Obliterans: An Overview of Recent Research

BACKGROUND

Thromboangiitis obliterans (TAO) is a nonatherosclerotic thromboticocclusive vasculitis that affects the vessels of the small and medium-sized extremities. No explicit etiology or pathogenesis of TAO has been proven, and more effective treatments are needed.

OBJECTIVE

The study aimed to summarize and present an overview of recent advances regarding the risk factors, mechanisms and treatments of TAO and to organize the related information in figures to provide a comparatively complete reference.

METHODS

We searched PubMed for English-language literature about TAO without article type limits, including articles about the risk factors, pathological mechanisms and treatments of TAO in the last 10 years with essential supplements (references over ranges and English abstracts of Russian literature).

RESULTS

After screening content of works of literature, 99 references were evaluated. We found that risk factors of TAO include smoking, gene factors and periodontal diseases. The underlying mechanism of TAO involves oxidative stress, immunity, hemodynamic changes, inflammation and so on. Moreover, similarities in genetic factors and cigarette relevance existed between periodontal diseases and TAO, so further study of relationship was required. For TAO treatment, medicine, endovascular intervention and revascularization surgery, autologous cell therapy and novel therapies were also mentioned. Besides, a hypothesis that infection triggers autoimmunity in TAO could be speculated, in which TLR4 plays a key role.

CONCLUSION

1. A hypothesis is put forward that infections can trigger autoimmunity in TAO development, in which TLR4, as a key agent, can activate immune signaling pathways and induce autoimmune cytokines expression. 2. It is suggested to reconsider the association between periodontal diseases and TAO, as they share the same high-risk population. Controlling periodontal disease severity in TAO studies may provide new clues. 3. For TAO treatment, endovascular intervention and autologous cell therapy both showed promising long-term therapeutic effectiveness, in which autologous cell therapy is becoming more popular, although more clinical comparisons are needed.

High mobility group box 1 mediates inflammatory response of astrocytes via cyclooxygenase 2/prostaglandin E2 signaling following spinal cord injury

High mobility group box 1 (HMGB1) interacts with pattern-recognition receptors of immune cells to activate the inflammatory response. Astrocytes play a positive role in the inflammatory response of the central nervous system by expressing a broad range of pattern-recognition receptors. However, the underlying relationship between HMGB1 and the inflammatory reaction of astrocytes remains unclear. In this study, we established rat models of spinal cord injury via laminectomy at the T8–10 level, and the injured spinal cord was subjected to transcriptome sequencing. Our results showed that the HMGB1/Toll-like receptor 4 (TLR4) axis was involved in the activation of astrocyte inflammatory response through regulation of cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) signaling. Both TLR4 and COX2 were distributed in astrocytes and showed elevated protein levels following spinal cord injury. Stimulation of primary astrocytes with recombinant HMGB1 showed that COX2 and microsomal PGE synthase (mPGES)-1, rather than COX1, mPGES-2, or cytosolic PGE synthase, were significantly upregulated. Accordingly, PGE2 production in astrocytes was remarkably increased in response to recombinant HMGB1 challenges. Pharmacologic blockade of TLR2/4 attenuated HMGB1-mediated activation of the COX2/PGE2 pathway. Interestingly, HMGB1 did not impact the production of tumor necrosis factor-α or interleukin-1β in astrocytes. Our results suggest that HMGB1 mediates the astrocyte inflammatory response through regulating the COX2/PGE2 signaling pathway. The study was approved by the Laboratory Animal Ethics Committee of Nantong University, China (approval No. 20181204-001) on December 4, 2018.

Immune-associated biomarkers for early diagnosis of Parkinson's disease based on hematological lncRNA-mRNA co-expression

Early stage diagnosis of Parkinson's disease (PD) is challenging without significant motor symptoms. The identification of effective molecular biomarkers as a hematological indication of PD may help improve the diagnostic timeliness and accuracy. In this paper, we analyzed and compared the blood samples of PD and control (CTR) patients to identify the disease-related changes and determine the putative biomarkers for PD diagnosis. Based on the RNA sequencing analysis, differentially expressed genes (DEGs) were identified, and the co-expression network of DEGs was constructed using the weighted correlation network analysis (WGCNA). The analysis leads to the identification of 87 genes that were exclusively regulated in the PD group, whereas 66 genes were significantly increased and 21 genes were significantly decreased in contrast to the control group. The results indicate that the core lncRNA-mRNA co-expression network greatly changes the immune response in PD patients. Specifically, the results showed that PWAR6, LINC00861, AC83843.1, IRF family, IFIT family and CaMK4 may play important roles in the immune system of PD. Based on the findings from this the present study, future research aims at identify novel therapeutic strategies for PD.

Porphyromonas gulae lipopolysaccharide elicits inflammatory responses through toll-like receptor 2 and 4 in human gingivalis epithelial cells

Porphyromonas gulae, a Gram-negative black-pigmented anaerobe, has been associated with periodontal disease in companion animals and its virulence has been attributed to various factors, including lipopolysaccharide (LPS), protease and fimbriae. Toll-like receptors (TLRs) recognise pathogen-associated molecular patterns, such as peptidoglycan, lipids, lipoproteins, nucleic acid and LPS. Following P. gulae infection, some inflammatory responses are dependent on both TLR2 and TLR4. In addition, a recent clinical study revealed that acute and persistent inflammatory responses enhance the expressions of TLR2 and TLR4 in the oral cavity. In this study, we investigated the interaction between P. gulae LPS and human gingivalis epithelial cells (Ca9-22 cells). P. gulae LPS was found to increase TLR2 and TLR4 mRNA expressions and protein productions, and enhanced inflammatory responses, such as COX₂ , TNF-ɑ, IL-6 and IL-8. Stimulated Ca9-22 cells exhibited phosphorylation of ERK1/2 and p38, and their inhibitors diminished inflammatory responses, while knockdown of the TLR2 and/or TLR4 genes with small interfering RNA (siRNA) prevented inflammatory responses. Moreover, p38 and ERK1/2 phosphorylation was decreased in TLR2 and TLR4 gene knockdown cells. These findings suggest that P. gulae LPS activates p38 and ERK1/2 via TLR2 and TLR4, leading to inflammatory responses in human gingival epithelial cells.

Manganese exposure caused reproductive toxicity of male mice involving activation of GnRH secretion in the hypothalamus by prostaglandin E2 receptors EP1 and EP2

Exposure to manganese (Mn) can cause male reproductive damage and lead to abnormal secretion of sex hormones. Gonadotropin-releasing hormone (GnRH) plays an important role in the neuromodulation of vertebrate reproduction. Astrocytes can indirectly regulate the secretion of GnRH by binding paracrine prostaglandin E₂ (PGE₂) specifically to the EP1 and EP2 receptors on GnRH neurons. Prior studies assessed the abnormal secretion of GnRH caused by Mn exposure, but the specific mechanism has not been reported in detail. This study investigated the effects of Mn exposure on the reproductive system of male mice to clarify the role of PGE₂ in the abnormal secretion of GnRH in the hypothalamus caused by exposure to Mn. Our data demonstrate that antagonizing the EP1 and EP2 receptors of PGE₂ can restore abnormal levels of GnRH caused by Mn exposure. Mn exposure causes reduced sperm count and sperm shape deformities. These findings suggest that EP1 and EP2, the receptors of PGE₂, may be the key to abnormal GnRH secretion caused by Mn exposure. Antagonizing the PGE₂ receptors may reduce reproductive damage caused by Mn exposure.

The Role of Brain Cyclooxygenase-2 (Cox-2) Beyond Neuroinflammation: Neuronal Homeostasis in Memory and Anxiety

Cyclooxygenases are a group of heme-containing isozymes (namely Cox-1 and Cox-2) that catalyze the conversion of arachidonic acid to largely bioactive prostaglandins (PGs). Cox-1 is the ubiquitous housekeeping enzyme, and the mitogen-inducible Cox-2 is activated to cause inflammation. Interestingly, Cox-2 is constitutively expressed in the brain at the postsynaptic dendrites and excitatory terminals of the cortical and spinal cord neurons. Neuronal Cox-2 is activated in response to synaptic excitation to yield PGE₂, the predominant Cox-2 metabolite in the brain, which in turn stimulates the release of glutamate and neuronal firing in a retrograde fashion. Cox-2 is also engaged in the metabolism of new endocannabinoids from 2-arachidonoyl-glycerol to modulate their actions at presynaptic terminals. In addition to these interactions, the induction of neuronal Cox-2 is coupled to the trans-synaptic activation of the dopaminergic mesolimbic system and some serotoninergic receptors, which might contribute to the development of emotional behavior. Although much of the focus regarding the induction of Cox-2 in the brain has been centered on neuroinflammation-related neurodegenerative and psychiatric disorders, some evidence also suggests that Cox-2 release during neuronal signaling may be pivotal for the fine tuning of cortical networks to regulate behavior. This review compiles the evidence supporting the homeostatic role of neuronal Cox-2 in synaptic transmission and plasticity, since neuroinflammation is originally triggered by the induction of glial Cox-2 expression. The goal is to provide perspective on the roles of Cox-2 beyond neuroinflammation, such as those played in memory and anxiety, and whose evidence is still scant.