Resolvin D1 Attenuates Innate Immune Reactions in Experimental Subarachnoid Hemorrhage Rat Model

Hydrogen inhalation therapy regulates lactic acid metabolism following subarachnoid hemorrhage through the HIF-1α pathway

The neuroprotective effects of hydrogen have been demonstrated, but the mechanism is still poorly understood. In a clinical trial of inhaled hydrogen in patients with subarachnoid hemorrhage (SAH), we found that hydrogen reduced the accumulation of lactic acid in the nervous system. There are no studies demonstrating the regulatory effect of hydrogen on lactate and in this study we hope to further clarify the mechanism by which hydrogen regulates lactate metabolism. In cell experiments, PCR and Western Blot showed that HIF-1α was the target related to lactic acid metabolism that changed the most before and after hydrogen intervention. HIF-1α levels were suppressed by hydrogen intervention treatment. Activation of HIF-1α inhibited the lactic acid-lowering effect of hydrogen. We have also demonstrated the lactic acid-lowering effect of hydrogen in animal studies. Our work clarifies that hydrogen can regulate lactate metabolism via the HIF-1αpathway, providing new insights into the neuroprotective mechanisms of hydrogen.

Declined Serum Resolvin D1 Levels to Predict Severity and Prognosis of Human Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study

Background

Resolvin D1 (RvD1) possesses anti-inflammatory properties and may be neuroprotective. This study was designed to ascertain the potential role of serum RvD1 in the evaluation of aSAH severity and prognosis of human aneurysmal subarachnoid hemorrhage (aSAH).

Methods

In this prospective observational study, serum RvD1 levels were measured in 123 patients with aSAH and in 123 healthy volunteers. Six-month neurological function was assessed using extended Glasgow outcome scale (GOSE). A prognostic prediction model was appraised using a series of evaluative tools, such as a nomogram, receiver operating characteristic (ROC) curve, decision curve, calibration curve, restricted cubic spline, and Hosmer-Lemeshow goodness of fit statistics.

Results

Serum RvD1 levels were markedly lower in patients than in controls (median, 0.54 versus 1.47 ng/mL; P<0.001). Serum RvD1 levels were independently correlated with Hunt-Hess scores (beta, -0.154; 95% confidence interval [CI], -0.198--0.109; VIF, 1.769; P=0.001), modified Fisher scores (beta, -0.066; 95% CI, -0.125--0.006; VIF, 1.567; P=0.031) and 6-month GOSE scores (beta, 1.864; 95% CI, 0.759-2.970; VIF, 1.911; P=0.001) and were independently predictive of a poor prognosis (GOSE scores of 1-4) (odds ratio, 0.137; 95% CI, 0.023-0.817; P=0.029). Serum RvD1 levels significantly distinguished the risk of a worse prognosis, with an area under the ROC curve of 0.750 (95% CI, 0.664-0.824). Using the Youden method, serum RvD1 levels < 0.6 ng/mL was effective in predicting worse prognosis with 84.1% sensitivity and 62.0% specificity. Moreover, the model containing serum RvD1 levels, Hunt-Hess scores and modified Fisher scores was efficient, reliable and beneficial in prognostic prediction using a series of the afore-mentioned evaluative tools.

Conclusion

A decline in serum RvD1 levels following aSAH is closely correlated with illness severity and independently predicts a worse outcome in patients with aSAH, implying that serum RvD1, as a prognostic biomarker of aSAH, may be of clinical value in aSAH.

Prognostic significance of serum resolvin D1 levels in patients with acute supratentorial intracerebral hemorrhage: a prospective longitudinal cohort study

OBJECTIVE

Resolvin D1 (RvD1) has anti-inflammatory properties and may be neuroprotective. This study was designed to assess usability of serum RvD1 as a prognostic biomarker after intracerebral hemorrhage (ICH).

METHODS

In this prospective, observational study of 135 patients and 135 controls, serum RvD1 levels were measured. Its relations to severity, early neurologic deterioration (END) and poststroke 6-month worse outcome (modified Rankin Scale scores of 3-6) were determined via multivariate analysis. Predictive effectiveness was evaluated based on area under receiver operating characteristic curve (AUC).

RESULTS

Patients had markedly lower serum RvD1 levels than controls (median, 0.69 ng/ml versus 2.15 ng/ml). Serum RvD1 levels were independently correlated with the National Institutes of Health Stroke Scale (NIHSS) [β, -0.036; 95% confidence interval (CI), -0.060--0.013; VIF, 2.633; t=-3.025; P=0.003] and hematoma volume (β, -0.019; 95% CI, -0.056--0.009; VIF, 1.688; t=-2.703; P=0.008). Serum RvD1 levels substantially discriminated risks of END and worse outcome with AUCs at 0.762 (95% CI, 0.681-0.831) and 0.783 (95% CI, 0.704-0.850) respectively. A RvD1 cut-off value of 0.85 ng/ml was effective in predicting END with a sensitivity of 95.0% and specificity of 48.4% and its levels <0.77 ng/ml distinguished patients at risk of worse outcome with a sensitivity of 84.5% and specificity of 63.6%. Under restricted cubic spline, serum RvD1 levels were linearly related to risk of END and worse outcome (both P>0.05). Serum RvD1 levels and NIHSS scores independently predicted END with odds ratio (OR) values of 0.082 (95% CI, 0.010-0.687) and 1.280 (95% CI, 1.084-1.513) respectively. Serum RvD1 levels (OR, 0.075; 95% CI, 0.011-0.521), hematoma volume (OR, 1.084; 95% CI, 1.035-1.135) and NIHSS scores (OR, 1.240; 95% CI, 1.060-1.452) were independently associated with worse outcome. END prediction model containing serum RvD1 levels and NIHSS scores, and prognostic prediction model containing serum RvD1 levels, hematoma volumes and NIHSS scores displayed efficient predictive ability with AUCs at 0.828 (95% CI, 0.754-0.888) and 0.873 (95% CI, 0.805-0.924) respectively. Such two models were visually shown via building two nomograms. Using Hosmer-Lemeshow test, calibration curve and decision curve, the models were comparatively stable and had clinical benefit.

CONCLUSION

There is a dramatical declination of serum RvD1 levels after ICH, which is tightly related to stroke severity and is independently predictive of poor clinical outcome, implying that serum RvD1 may be of clinical significance as a prognostic marker of ICH.

LDC7559 inhibits microglial activation and GSDMD-dependent pyroptosis after subarachnoid hemorrhage

Mounting evidence indicates that inhibition of microglial activation and neuronal pyroptosis plays important roles in brain function recovery after subarachnoid hemorrhage (SAH). LDC7559 is a newly discovered gasdermin D (GSDMD) inhibitor. Previous studies have demonstrated that LDC7559 could inhibit microglial proliferation and pyroptosis. However, the beneficial effects of LDC7559 on SAH remain obscure. Based on this background, we investigated the potential role and the mechanism of LDC7559 on SAH-induced brain damage both in vivo and in vitro. The findings revealed that microglial activation and neuronal pyroptosis were evidently increased after SAH, which could be markedly suppressed by LDC7559 both in vivo and in vitro. Meanwhile, LDC7559 treatment reduced neuronal apoptosis and improved behavior function. Mechanistically, LDC7559 decreased the levels of GSDMD and cleaved GSDMD after SAH. In contrast, nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome activation by nigericin increased GSDMD-mediated pyroptosis and abated the beneficial effects of LDC7559 on SAH-induced brain damage. However, LDC7559 treatment did not significantly affect the expression of NLRP3 after SAH. Taken together, LDC7559 might suppress neuronal pyroptosis and microglial activation after SAH by inhibiting GSDMD, thereby promoting brain functional recovery.

Peroxiredoxin 2 Is a Potential Objective Indicator for Severity and the Clinical Status of Subarachnoid Hemorrhage Patients

Purpose

We have demonstrated that peroxiredoxin 2 (Prx2) released from lytic erythrocytes and damaged neurons into the subarachnoid space could activate microglia and then result in neuronal apoptosis. In this study, we tested the possibility of using Prx2 as an objective indicator for severity of the subarachnoid hemorrhage (SAH) and the clinical status of the patient.

Materials and Methods

SAH patients were prospectively enrolled and followed up for 3 months. Cerebrospinal fluid (CSF) and blood samples were collected 0-3 and 5-7 days after SAH onset. The levels of Prx2 in the CSF and the blood were measured by an enzyme-linked immunosorbent assay (ELISA). We used Spearman's rank coefficient to assess the correlation between Prx2 and the clinical scores. Receiver operating characteristic (ROC) curves were used for Prx2 levels to predict the outcome of SAH by calculating the area under the curve (AUC). Unpaired Student's t-test was used to analyze the differences in continuous variables across cohorts.

Results

Prx2 levels in the CSF increased after onset while those in the blood decreased. Existing data showed that Prx2 levels within 3 days in the CSF after SAH were positively correlated with the Hunt-Hess score (R = 0.761, P < 0.001). Patients with CVS had higher levels of Prx2 in their CSF within 5-7 days after onset. Prx2 levels in the CSF within 5-7 days can be used as a predictor of prognosis. The ratio of Prx2 in the CSF and the blood within 3 days of onset was positively correlated with the Hunt-Hess score and negatively correlated with Glasgow Outcome Scale (GOS; R = -0.605, P < 0.05).

Conclusion

We found that the levels of Prx2 in the CSF and the ratio of Prx2 in the CSF and the blood within 3 days of onset can be used as a biomarker to detect the severity of the disease and the clinical status of the patient.

PHLDA1 modulates microglial response and NLRP3 inflammasome signaling following experimental subarachnoid hemorrhage

Balancing microglia M1/M2 polarization is an effective therapeutic strategy for neuroinflammation after subarachnoid hemorrhage (SAH). Pleckstrin homology-like domain family A member 1 (PHLDA1) has been demonstrated to play a crucial role in immune response. However, the function roles of PHLDA1 in neuroinflammation and microglial polarization after SAH remain unclear. In this study, SAH mouse models were assigned to treat with scramble or PHLDA1 small interfering RNAs (siRNAs). We observed that PHLDA1 was significantly increased and mainly distributed in microglia after SAH. Concomitant with PHLDA1 activation, nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome expression in microglia was also evidently enhanced after SAH. In addition, PHLDA1 siRNA treatment significantly reduced microglia-mediated neuroinflammation by inhibiting M1 microglia and promoting M2 microglia polarization. Meanwhile, PHLDA1 deficiency reduced neuronal apoptosis and improved neurological outcomes after SAH. Further investigation revealed that PHLDA1 blockade suppressed the NLRP3 inflammasome signaling after SAH. In contrast, NLRP3 inflammasome activator nigericin abated the beneficial effects of PHLDA1 deficiency against SAH by promoting microglial polarization to M1 phenotype. In all, we proposed that PHLDA1 blockade might ameliorate SAH-induced brain injury by balancing microglia M1/M2 polarization via suppression of NLRP3 inflammasome signaling. Targeting PHLDA1 might be a feasible strategy for treating SAH.

Resolvins Lipid Mediators: Potential Therapeutic Targets in Alzheimer and Parkinson Disease

Inflammation and resolution are highly programmed processes involving a plethora of immune cells. Lipid mediators synthesized from arachidonic acid metabolism play a pivotal role in orchestrating the signaling cascades in the game of inflammation. The majority of the studies carried out so far on inflammation were aimed at inhibiting the generation of inflammatory molecules, whereas recent research has shifted more towards understanding the resolution of inflammation. Owing to chronic inflammation as evident in neuropathophysiology, the resolution of inflammation together with the class of lipid mediators actively involved in its regulation has attracted the attention of the scientific community as therapeutic targets. Both omega-three polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, orchestrate a vital regulatory role in inflammation development. Resolvins derived from these fatty acids comprise the D-and E-series resolvins. A growing body of evidence using in vitro and in vivo models has revealed the pro-resolving and anti-inflammatory potential of resolvins. This systematic review sheds light on the synthesis, specialized receptors, and resolution of inflammation mediated by resolvins in Alzheimer's and Parkinson's disease.

Pterostilbene Attenuates Subarachnoid Hemorrhage-Induced Brain Injury through the SIRT1-Dependent Nrf2 Signaling Pathway

Neuroinflammatory injury, oxidative insults, and neuronal apoptosis are major causes of poor outcomes after subarachnoid hemorrhage (SAH). Pterostilbene (PTE), an analog of resveratrol, has been verified as a potent sirtuin 1 (SIRT1) activator. However, the beneficial actions of PTE on SAH-induced brain injury and whether PTE regulates SIRT1 signaling after SAH remain unknown. We first evaluated the dose-response influence of PTE on early brain impairment after SAH. In addition, EX527 was administered to suppress SIRT1 signaling. The results revealed that PTE significantly attenuated microglia activation, oxidative insults, neuronal damage, and early neurological deterioration. Mechanistically, PTE effectively enhanced SIRT1 expression and promoted nuclear factor-erythroid 2-related factor 2 (Nrf2) accumulation in nuclei. Furthermore, EX527 pretreatment distinctly repressed PTE-induced SIRT1 and Nrf2 activation and deteriorated these beneficial outcomes. In all, our study provides the evidence that PTE protects against SAH insults by activating SIRT1-dependent Nrf2 signaling pathway. PTE might be a therapeutic alternative for SAH.

Activation of Sirtuin-1 by Pinocembrin Treatment Contributes to Reduced Early Brain Injury after Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) as a devastating neurological disorder is closely related to heightened oxidative insults and neuroinflammatory injury. Pinocembrin, a bioflavonoid, exhibits different biological functions, such as immunomodulatory, anti-inflammatory, antioxidative, and cerebroprotective activities. Herein, we examined the protective effects and molecular mechanisms of pinocembrin in a murine model of SAH. Using an endovascular perforation model in rats, pinocembrin significantly mitigated SAH-induced neuronal tissue damage, including inflammatory injury and free-radical insults. Meanwhile, pinocembrin improved behavior function and reduced neuronal apoptosis. We also revealed that sirtuin-1 (SIRT1) activation was significantly enhanced by pinocembrin. In addition, pinocembrin treatment evidently enhanced peroxisome proliferator-activated receptor-γ coactivator expression and suppressed ac-nuclear factor-kappa B levels. In contrast, EX-527, a selective SIRT1 inhibitor, blunted the protective effects of pinocembrin against SAH by suppressing SIRT1-mediated signaling. These results suggested that the cerebroprotective actions of pinocembrin after SAH were through SIRT1-dependent pathway, suggesting the potential application of pinocembrin for the treatment of SAH.

Downregulated formyl peptide receptor 2 expression in the epileptogenic foci of patients with focal cortical dysplasia type IIb and tuberous sclerosis complex

BACKGROUND

Focal cortical dysplasia type IIb (FCDIIb) and tuberous sclerosis complex (TSC) show persistent neuroinflammation, which promotes epileptogenesis and epilepsy progression, suggesting that endogenous resolution of inflammation is inadequate to relieve neuronal network hyperexcitability. To explore the potential roles of formyl peptide receptor 2 (FPR2), which is a key regulator of inflammation resolution, in epilepsy caused by FCDIIb and TSC, we examined the expression and cellular distribution of FPR2.

METHOD

The expression of FPR2 and nuclear factor-κB (NF-κB) signaling pathway was examined by real-time PCR, western blots, and analyzed via one-way analysis of variance. The distribution of FPR2 was detected using immunostaining. The expression of resolvin D1 (RvD1, the endogenous ligand of FPR2) was observed via enzyme-linked immunosorbent assay. Pearson's correlation test was used to evaluate the correlation between the expression levels of FPR2 and RvD1 and the clinical variants.

RESULTS

The expression of FPR2 was significantly lower in FCDIIb (p = .0146) and TSC (p = .0006) cortical lesions than in controls, as was the expression of RvD1 (FCDIIb: p = .00431; TSC: p = .0439). Weak FPR2 immunoreactivity was observed in dysmorphic neurons (DNs), balloon cells (BCs), and giant cells (GCs) in FCDIIb and TSC tissues. Moreover, FPR2 was mainly distributed in dysplastic neurons; it was sparse in microglia and nearly absent in astrocytes. The NF-κB pathway was significantly activated in patients with FCDIIb and TSC, and the protein level of NF-κB was negatively correlated with the protein level of FPR2 (FCDIIb: p = .00395; TSC: p = .0399). In addition, the protein level of FPR2 was negatively correlated with seizure frequency in FCDIIb (p = .0434) and TSC (p = .0351) patients.

CONCLUSION

In summary, these results showed that the expression and specific distribution of FPR2 may be involved in epilepsy caused by FCDIIb and TSC, indicating that downregulation of FPR2 mediated the dysfunction of neuroinflammation resolution in FCDIIb and TSC.

Isoliquiritigenin mitigates oxidative damage after subarachnoid hemorrhage in vivo and in vitro by regulating Nrf2-dependent Signaling Pathway via Targeting of SIRT1

BACKGROUND

Oxidative stress is a crucial factor leading to subarachnoid hemorrhage (SAH)-induced early brain injury (EBI). Isoliquiritigenin has been verified as a powerful anti-oxidant in a variety of diseases models and can activate sirtuin 1 and nuclear factor-erythroid 2-related factor 2 (Nrf2) pathways. However, the effects of isoliquiritigenin against EBI after SAH and the underlying mechanisms remain elusive.

PURPOSE

The primary goal of this study is to verify the therapeutic effects of isoliquiritigenin on EBI after SAH and the possible molecular mechanisms.

STUDY DESIGN

A prechiasmatic cistern SAH model in rats and a hemoglobin incubation SAH model in primary neurons were established. Isoliquiritigenin was administered after SAH induction. EX527 was employed to inhibit sirtuin 1 activation and ML385 was used to suppress Nrf2 signaling.

METHODS

In our study, neurological scores, brain edema, biochemical estimation, western blotting, and histopathological study were performed to explore the therapeutic action of isoliquiritigenin against SAH.

RESULTS

Our data revealed that isoliquiritigenin significantly mitigated oxidative damage after SAH as evidenced by decreased reactive oxygen species overproduction and enhanced intrinsic anti-oxidative system. Concomitant with the reduced oxidative insults, isoliquiritigenin improved neurological function and reduced neuronal death in the early period after SAH. Additionally, isoliquiritigenin administration significantly enhanced Nrf2 and sirtuin 1 expressions. Inhibition of Nrf2 by ML385 reversed the anti-oxidative and neuroprotective effects of isoliquiritigenin against SAH. Moreover, inhibiting sirtuin 1 by EX527 pretreatment suppressed isoliquiritigenin-induced Nrf2-dependent pathway and abated the cerebroprotective effects of isoliquiritigenin. In primary cortical neurons, isoliquiritigenin treatment also ameliorated oxidative insults and repressed neuronal degeneration. The beneficial aspects of isoliquiritigenin were attributed to the promotion of sirtuin 1 and Nrf2 signaling pathways and were counteracted by EX527.

CONCLUSION

Our findings suggest that isoliquiritigenin exerts cerebroprotective effects against SAH-induced oxidative insults by modulating the Nrf2-mediated anti-oxidant signaling in part through sirtuin 1 activation. Isoliquiritigenin might be a new potential drug candidate for SAH.

Resolvin D1: A key endogenous inhibitor of neuroinflammation

After the initiation of inflammation, a series of processes start to resolve the inflammation. A group of endogenous lipid mediators, namely specialized pro-resolving lipid mediators is at the top list of inflammation resolution. Resolvin D1 (RvD1), is one of the lipid mediators with significant anti-inflammatory properties. It is produced from docosahexaenoic acid (omega-3 polyunsaturated fatty acid) in the body. In this article, we aimed to review the most recent findings concerning the pharmacological effects of RvD1 in the central nervous system with a focus on major neurological diseases and dysfunctions. A literature review of the past studies demonstrated that RvD1 plasma level changes during mania, depression, and Parkinson's disease. Furthermore, RVD1 and its epimer, aspirin-triggered RvD1 (AT-RvD1), have significant therapeutic effects on experimental models of ischemic and traumatic brain injuries, memory dysfunction, pain, depression, amyotrophic lateral sclerosis, and Alzheimer's and Parkinson's diseases. Interestingly, the beneficial effects of RvD1 and AT-RvD1 were mostly induced at nanomolar and micromolar concentrations implying the significant potency of these lipid mediators in treating diseases with inflammation.

Effect of Chlorogenic Acid via Upregulating Resolvin D1 Inhibiting the NF-κB Pathway on Chronic Restraint Stress-Induced Liver Inflammation

Chronic stress can cause chronic inflammatory injury to the liver. Chlorogenic acid (CGA) is known to have a wide range of biological activities and anti-inflammatory effects. Resolvin D1 (RvD1) is a polyunsaturated fatty acid derivative that has inhibitory effects on a variety of inflammatory diseases. However, whether CGA can inhibit liver inflammation in chronic stress through RvD1 remains unclear. In this work, male rats were subjected to restraint stress for 6 h every day and built a chronic stress model for 21 days. CGA (100 mg/kg) was administered intragastrically 1 h before restraint, with intraperitoneal injection of RvD1 inhibitor WRW4 (antagonist of FPR2, 0.1 mg/kg) or WRW4 solution every 2 days for 30 min before CGA administration. CGA reduced hepatic hemorrhage and inflammatory cell infiltration, alleviated hepatic injury, decreased the activation of the NF-κB pathway and the expression of interleukin 1β, interleukin 6, and tumor necrosis factor α in the liver, and increased RvD1 in the serum and liver. The therapeutic effect of CGA was blocked after WRW4 intervention. These results suggest that the protective effects of CGA mediate the NF-κB pathway by upregulating the generation of RvD1. Above all, this research demonstrates the liver protective effect of CGA and provides a potential treatment strategy for chronic inflammatory disease.

Cycloastragenol Confers Cerebral Protection after Subarachnoid Hemorrhage by Suppressing Oxidative Insults and Neuroinflammation via the SIRT1 Signaling Pathway

Subarachnoid hemorrhage (SAH) is an acute cerebral vascular disease featured by oxidative insults and neuroinflammation. Cycloastragenol (CAG), the major active component of Astragalus radix, has a wide range of biological functions. However, the potential beneficial effects and the underlying molecular mechanisms of CAG on SAH remain obscure. In the current study, the cerebroprotective effects and mechanism of CAG on SAH were evaluated both in vivo and in vitro. Our results indicated that CAG significantly suppressed SAH-triggered oxidative insults, inflammatory mediators production, microglia activation, and the neutrophil infiltration in the brain. In addition, CAG improved neurological function and ameliorated neuronal apoptosis and degeneration after SAH. In vitro results also revealed the therapeutic effects of CAG on neurons and microglia co-culture system. Mechanistically, CAG treatment upregulated sirtuin 1 (SIRT1) expression, inhibited the levels of FoxO1, nuclear factor-kappa B, and p53 acetylation, and suppressed the subsequent oxidative, inflammatory, and apoptotic pathways. In contrast, inhibiting SIRT1 by pretreatment with Ex527 abrogated the protective actions of CAG both in vivo and in vitro models of SAH. Collectively, our findings indicated that CAG could be a promising and effective drug candidate for SAH.

Lipidomic Profiling in Synovial Tissue

The analysis of synovial tissue offers the potential for the comprehensive characterization of cell types involved in arthritis pathogenesis. The studies performed to date in synovial tissue have made it possible to define synovial pathotypes, which relate to disease severity and response to treatment. Lipidomics is the branch of metabolomics that allows the quantification and identification of lipids in different biological samples. Studies in animal models of arthritis and in serum/plasma from patients with arthritis suggest the involvement of different types of lipids (glycerophospholipids, glycerolipids, sphingolipids, oxylipins, fatty acids) in the pathogenesis of arthritis. We reviewed studies that quantified lipids in different types of tissues and their relationship with inflammation. We propose that combining lipidomics with currently used “omics” techniques can improve the information obtained from the analysis of synovial tissue, for a better understanding of pathogenesis and the development of new therapeutic strategies.

The role of Resolvin D1 in liver diseases

The liver is a parenchymatous organ closely related to immunity, detoxification and metabolism of the three major nutrients. The inflammatory response is a protective mechanism of the body to eliminate harmful stimuli. However, continuous inflammatory stimulation leads to occurrence of many liver diseases and brings great social burden. Resolvin D1, a member of the specialized pro-resolving lipid mediators family, exerts anti-inflammatory, anti-oxidant stress, anti-fibrosis, anti-apoptotic, and anti-tumor effects by binding to ALX/FPR2 or GPR32. RvD1 plays an important role and has great therapeutic potential in liver diseases, which has been validated in multiple models of preclinical disease. This review will provide a detailed summary of the role of RvD1 in different liver diseases, including acute liver injury, liver ischemia/reperfusion injury, non-alcoholic fatty liver disease, liver fibrosis, and liver cancer, so as to help people have a more comprehensive understanding of RvD1 and promote its further research.

Phospholipase A2 enzymes represent a shared pathogenic pathway in psoriasis and pityriasis rubra pilaris

Altered epidermal differentiation along with increased keratinocyte proliferation is a characteristic feature of psoriasis and pityriasis rubra pilaris (PRP). However, despite this large degree of overlapping clinical and histologic features, the molecular signatures these skin disorders share are unknown. Using global transcriptomic profiling, we demonstrate that plaque psoriasis and PRP skin lesions have high overlap, with all differentially expressed genes in PRP relative to normal skin having complete overlap with those in psoriasis. The major common pathway shared between psoriasis and PRP involves the phospholipases PLA2G2F, PLA2G4D, and PLA2G4E, which were found to be primarily expressed in the epidermis. Gene silencing each of the 3 PLA2s led to reduction in immune responses and epidermal thickness both in vitro and in vivo in a mouse model of psoriasis, establishing their proinflammatory roles. Lipidomic analyses demonstrated that PLA2s affect mobilization of a phospholipid-eicosanoid pool, which is altered in psoriatic lesions and functions to promote immune responses in keratinocytes. Taken together, our results highlight the important role of PLA2s as regulators of epidermal barrier homeostasis and inflammation, identify PLA2s as a shared pathogenic mechanism between PRP and psoriasis, and as potential therapeutic targets for both diseases.

Activated protein C overexpression suppresses the pyroptosis of subarachnoid hemorrhage model cells by regulating the NLRP3 inflammasome pathway

Subarachnoid hemorrhage (SAH) is a condition with a high associated mortality rate that is caused by hemorrhagic stroke. Activated protein C (APC) serves a neuroprotective role in central nervous system diseases. However, its role in SAH remains unclear. The present study aimed to investigate the role of APC and its regulatory mechanism in SAH. The SAH rat model was constructed through internal carotid artery puncture, while the SAH cell model was established via the application of oxygenated hemoglobin. ELISA was performed to detect the level of cytokines, and flow cytometry was used to determine the population of pyroptotic cells. Reverse transcription-quantitative PCR and western blotting were used to examine the relative mRNA and protein levels of APC. APC was silenced using specific APC short hairpin RNA. Neurological functions of rats were estimated using modified Garcia scoring and the balance beam test, while SAH was estimated using modified Sugawara's scoring. The results demonstrated that the expression of APC was significantly decreased, whereas the expression of NLR family pyrin domain-containing 3 (NLRP3) was increased in the SAH rat model in a time-dependent manner. The application of APC recombinant protein 3K3A-APC could significantly ameliorate SAH and improve neurological functions. In addition, 3K3A-APC could inhibit pyroptosis in a dose-dependent manner in the SAH cell model. Moreover, the NLRP3 inhibitor BAY11-7082 could reverse the upregulation of pyroptosis induced by APC-knockdown. Overall, the present study revealed that APC could ameliorate SAH-induced early brain injury by suppressing pyroptosis via inhibition of the NLRP3 inflammasome, which could provide a novel strategy for the treatment of SAH.

The Role of Formyl Peptide Receptors in Neurological Diseases via Regulating Inflammation

Formyl peptide receptors (FPRs) are a group of G protein-coupled cell surface receptors that play important roles in host defense and inflammation. Owing to the ubiquitous expression of FPRs throughout different cell types and since they interact with structurally diverse chemotactic agonists, they have a dual function in inflammatory processes, depending on binding with different ligands so that accelerate or inhibit key intracellular kinase-based regulatory pathways. Neuroinflammation is closely associated with the pathogenesis of neurodegenerative diseases, neurogenic tumors and cerebrovascular diseases. From recent studies, it is clear that FPRs are important biomarkers for neurological diseases as they regulate inflammatory responses by monitoring glial activation, accelerating neural differentiation, regulating angiogenesis, and controlling blood brain barrier (BBB) permeability, thereby affecting neurological disease progression. Given the complex mechanisms of neurological diseases and the difficulty of healing, we are eager to find new and effective therapeutic targets. Here, we review recent research about various mechanisms of the effects generated after FPR binding to different ligands, role of FPRs in neuroinflammation as well as the development and prognosis of neurological diseases. We summarize that the FPR family has dual inflammatory functional properties in central nervous system. Emphasizing that FPR2 acts as a key molecule that mediates the active resolution of inflammation, which binds with corresponding receptors to reduce the expression and activation of pro-inflammatory composition, govern the transport of immune cells to inflammatory tissues, and restore the integrity of the BBB. Concurrently, FPR1 is essentially related to angiogenesis, cell proliferation and neurogenesis. Thus, treatment with FPRs-modulation may be effective for neurological diseases.