Proresolving lipid mediators and mechanisms in the resolution of acute inflammation

Occult hypoperfusion and changes of systemic lipid levels after severe trauma: an analysis in a standardized porcine polytrauma model

BACKGROUND

Occult hypoperfusion describes the absence of sufficient microcirculation despite normal vital signs. It is known to be associated with prolonged elevation of serum lactate and later complications in severely injured patients. We hypothesized that changes in circulating lipids are related to responsiveness to resuscitation. The purpose of this study is investigating the relation between responsiveness to resuscitation and lipidomic course after poly trauma.

METHODS

Twenty-five male pigs were exposed a combined injury of blunt chest trauma, liver laceration, controlled haemorrhagic shock, and femoral shaft fracture. After 1 h, animals received resuscitation and fracture stabilization. Venous blood was taken regularly and 233 specific lipids were analysed. Animals were divided into two groups based on serum lactate level at the end point as an indicator of responsiveness to resuscitation (<2 mmol/L: responder group (R group), ≧2 mmol/L: occult hypoperfusion group (OH group)).

RESULTS

Eighteen animals met criteria for the R group, four animals for the OH group, and three animals died. Acylcarnitines showed a significant increase at 1 h compared to baseline in both groups. Six lipid subgroups showed a significant increase only in R group at 2 h. There was no significant change at other time points.

CONCLUSIONS

Six lipid groups increased significantly only in the R group at 2 h, which may support the idea that they could serve as potential biomarkers to help us to detect the presence of occult hypoperfusion and insufficient resuscitation. We feel that further study is required to confirm the role and mechanism of lipid changes after trauma.

The role of specialized pro-resolving mediators (SPMs) in inflammatory arthritis: A therapeutic strategy

Rheumatoid arthritis (RA) is classified as a persistent inflammatory autoimmune disorder leading to the subsequent erosion of articular cartilage and bone tissue originating from the synovium. The fundamental objective of therapeutic interventions in RA has been the suppression of inflammation. Nevertheless, conventional medicines that lack target specificity may exhibit unpredictable effects on cell metabolism. In recent times, there has been evidence suggesting that specialized pro-resolving mediators (SPMs), which are lipid metabolites, have a role in facilitating the resolution of inflammation and the reestablishment of tissue homeostasis. SPMs are synthesized by immune cells through the enzymatic conversion of omega-3 fatty acids. In the context of RA, there is a possibility of dysregulation in the production of these SPMs. In this review, we delve into the present comprehension of the endogenous functions of SPMs in RA as lipids that exhibit pro-resolutive, protective, and immunoresolvent properties.

Inflammation Resolution in the Cardiovascular System: Arterial Hypertension, Atherosclerosis, and Ischemic Heart Disease

Significance: Chronic inflammation has emerged as a major underlying cause of many prevalent conditions in the Western world, including cardiovascular diseases. Although targeting inflammation has emerged as a promising avenue by which to treat cardiovascular disease, it is also associated with increased risk of infection. Recent Advances: Though previously assumed to be passive, resolution has now been identified as an active process, mediated by unique immunoresolving mediators and mechanisms designed to terminate acute inflammation and promote tissue repair. Recent work has determined that failures of resolution contribute to chronic inflammation and the progression of human disease. Specifically, failure to produce pro-resolving mediators and the impaired clearance of dead cells from inflamed tissue have been identified as major mechanisms by which resolution fails in disease. Critical Issues: Drawing from a rapidly expanding body of experimental and clinical studies, we review here what is known about the role of inflammation resolution in arterial hypertension, atherosclerosis, myocardial infarction, and ischemic heart disease. For each, we discuss the involvement of specialized pro-resolving mediators and pro-reparative cell types, including T regulatory cells, myeloid-derived suppressor cells, and macrophages. Future Directions: Pro-resolving therapies offer the promise of limiting chronic inflammation without impairing host defense. Therefore, it is imperative to better understand the mechanisms underlying resolution to identify therapeutic targets. Antioxid. Redox Signal. 40, 292-316.

Research progress of targeted therapy regulating Th17/Treg balance in bone immune diseases

Rheumatoid arthritis (RA) and postmenopausal osteoporosis (PMOP) are common bone-immune diseases. The imbalance between helper (Th17) and regulatory T cells (Tregs) produced during differentiation of CD4+ T cells plays a key regulatory role in bone remodelling disorders in RA and PMOP. However, the specific regulatory mechanism of this imbalance in bone remodelling in RA and PMOP has not been clarified. Identifying the regulatory mechanism underlying the Th17/Treg imbalance in RA and PMOP during bone remodelling represents a key factor in the research and development of new drugs for bone immune diseases. In this review, the potential roles of Th17, Treg, and Th17/Treg imbalance in regulating bone remodelling in RA and PMOP have been summarised, and the potential mechanisms by which probiotics, traditional Chinese medicine compounds, and monomers maintain bone remodelling by regulating the Th17/Treg balance are expounded. The maintenance of Th17/Treg balance could be considered as an therapeutic alternative for the treatment of RA and PMOP. This study also summarizes the advantages and disadvantages of conventional treatments and the quality of life and rehabilitation of patients with RA and PMOP. The findings presented her will provide a better understanding of the close relationship between bone immunity and bone remodelling in chronic bone diseases and new ideas for future research, prevention, and treatment of bone immune diseases.

Efficient pulmonary lymphatic drainage is necessary for inflammation resolution in ARDS

The lymphatic vasculature is the natural pathway for the resolution of inflammation, yet the role of pulmonary lymphatic drainage function in sepsis-induced acute respiratory distress syndrome (ARDS) remains poorly characterized. In this study, indocyanine green-near infrared lymphatic living imaging was performed to examine pulmonary lymphatic drainage function in septic mouse models. We found that the pulmonary lymphatic drainage was impaired owing to the damaged lymphatic structure in sepsis-induced ARDS. Moreover, prior lymphatic defects by blocking vascular endothelial growth factor receptor-3 (VEGFR-3) worsened sepsis-induced lymphatic dysfunction and inflammation. Posttreatment with vascular endothelial growth factor-C (Cys156Ser) (VEGF-C156S), a ligand of VEGFR-3, ameliorated lymphatic drainage by rejuvenating lymphatics to reduce the pulmonary edema and promote draining of pulmonary macrophages and neutrophils to pretracheal lymph nodes. Meanwhile, VEGF-C156S posttreatment reversed sepsis-inhibited CC chemokine ligand 21 (CCL21), which colocalizes with pulmonary lymphatic vessels. Furthermore, the advantages of VEGF-C156S on the drainage of inflammatory cells and edema fluid were abolished by blocking VEGFR-3 or CCL21. These results suggest that efficient pulmonary lymphatic drainage is necessary for inflammation resolution in ARDS. Our findings offer a therapeutic approach to sepsis-induced ARDS by promoting lymphatic drainage function.

Lipid peroxidation of immune cells in cancer

Growing evidence indicates that cellular metabolism is a critical determinant of immune cell viability and function in antitumor immunity and lipid metabolism is important for immune cell activation and adaptation to the tumor microenvironment (TME). Lipid peroxidation is a process in which oxidants attack lipid-containing carbon-carbon double bonds and is an important part of lipid metabolism. In the past decades, studies have shown that lipid peroxidation participates in signal transduction to control cell proliferation, differentiation, and cell death, which is essential for cell function execution and human health. More importantly, recent studies have shown that lipid peroxidation affects immune cell function to modulate tumor immunity and antitumor ability. In this review, we briefly overview the effect of lipid peroxidation on the adaptive and innate immune cell activation and function in TME and discuss the effectiveness and sensitivity of the antitumor ability of immune cells by regulating lipid peroxidation.

Mouse Model of Nitrogen Mustard Ocular Surface Injury Characterization and Sphingolipid Signaling

Vesicating chemicals like sulfur mustard (SM) or nitrogen mustard (NM) can cause devastating damage to the eyes, skin, and lungs. Eyes, being the most sensitive, have complicated pathologies that can manifest immediately after exposure (acute) and last for years (chronic). No FDA-approved drug is available to be used as medical counter measures (MCMs) against such injuries. Understanding the pathological mechanisms in acute and chronic response of the eye is essential for developing effective MCMs. Here, we report the clinical and histopathological characterization of a mouse model of NM-induced ocular surface injury (entire surface) developed by treating the eye with 2% (w/v) NM solution for 5 min. Unlike the existing models of specific injury, our model showed severe ocular inflammation, including the eyelids, structural deformity of the corneal epithelium and stroma, and diminished visual and retinal functions. We also observed alterations of the inflammatory markers and their expression at different phases of the injury, along with an activation of acidic sphingomyelinase (aSMase), causing an increase in bioactive sphingolipid ceramide and a reduction in sphingomyelin levels. This novel ocular surface mouse model recapitulated the injuries reported in human, rabbit, and murine SM or NM injury models. NM exposure of the entire ocular surface in mice, which is similar to accidental or deliberate exposure in humans, showed severe ocular inflammation and caused irreversible alterations to the corneal structure and significant vision loss. It also showed an intricate interplay between inflammatory markers over the injury period and alteration in sphingolipid homeostasis in the early acute phase.

15-Lipoxygenase promotes resolution of inflammation in lymphedema by controlling Treg cell function through IFN-β

Lymphedema (LD) is characterized by the accumulation of interstitial fluid, lipids and inflammatory cell infiltrate in the limb. Here, we find that LD tissues from women who developed LD after breast cancer exhibit an inflamed gene expression profile. Lipidomic analysis reveals decrease in specialized pro-resolving mediators (SPM) generated by the 15-lipoxygenase (15-LO) in LD. In mice, the loss of SPM is associated with an increase in apoptotic regulatory T (Treg) cell number. In addition, the selective depletion of 15-LO in the lymphatic endothelium induces an aggravation of LD that can be rescued by Treg cell adoptive transfer or ALOX15-expressing lentivector injections. Mechanistically, exogenous injections of the pro-resolving cytokine IFN-β restores both 15-LO expression and Treg cell number in a mouse model of LD. These results provide evidence that lymphatic 15-LO may represent a therapeutic target for LD by serving as a mediator of Treg cell populations to resolve inflammation.

Single cell RNA sequencing reveals endothelial cell killing and resolution pathways in experimental malaria-associated acute respiratory distress syndrome

Plasmodium parasites cause malaria, a global health disease that is responsible for more than 200 million clinical cases and 600 000 deaths each year. Most deaths are caused by various complications, including malaria-associated acute respiratory distress syndrome (MA-ARDS). Despite the very rapid and efficient killing of parasites with antimalarial drugs, 15% of patients with complicated malaria succumb. This stresses the importance of investigating resolution mechanisms that are involved in the recovery from these complications once the parasite is killed. To study the resolution of MA-ARDS, P. berghei NK65-infected C57BL/6 mice were treated with antimalarial drugs after onset of symptoms, resulting in 80% survival. Micro-computed tomography revealed alterations of the lungs upon infection, with an increase in total and non-aerated lung volume due to edema. Whole body plethysmography confirmed a drastically altered lung ventilation, which was restored during resolution. Single-cell RNA sequencing indicated an increased inflammatory state in the lungs upon infection, which was accompanied by a drastic decrease in endothelial cells, consistent with CD8+ T cell-mediated killing. During resolution, anti-inflammatory pathways were upregulated and proliferation of endothelial cells was observed. MultiNicheNet interactome analysis identified important changes in the ligand-receptor interactions during disease resolution that warrant further exploration in order to develop new therapeutic strategies. In conclusion, our study provides insights in pro-resolving pathways that limit inflammation and promote endothelial cell proliferation in experimental MA-ARDS. This information may be useful for the design of adjunctive treatments to enhance resolution after Plasmodium parasite killing by antimalarial drugs.

The Known Biology of Neuropathic Pain and Its Relevance to Pain Management

Patients with neuropathic pain are heterogeneous in pathophysiology, etiology, and clinical presentation. Signs and symptoms are determined by the nature of the injury and factors such as genetics, sex, prior injury, age, culture, and environment. Basic science has provided general information about pain etiology by studying the consequences of peripheral injury in rodent models. This is associated with the release of inflammatory cytokines, chemokines, and growth factors that sensitize sensory nerve endings, alter gene expression, promote post-translational modification of proteins, and alter ion channel function. This leads to spontaneous activity in primary afferent neurons that is crucial for the onset and persistence of pain and the release of secondary mediators such as colony-stimulating factor 1 from primary afferent terminals. These promote the release of tertiary mediators such as brain-derived neurotrophic factor and interleukin-1β from microglia and astrocytes. Tertiary mediators facilitate the transmission of nociceptive information at the spinal, thalamic, and cortical levels. For the most part, these findings have failed to identify new therapeutic approaches. More recent basic science has better mirrored the clinical situation by addressing the pathophysiology associated with specific types of injury, refinement of methodology, and attention to various contributory factors such as sex. Improved quantification of sensory profiles in each patient and their distribution into defined clusters may improve translation between basic science and clinical practice. If such quantification can be traced back to cellular and molecular aspects of pathophysiology, this may lead to personalized medicine approaches that dictate a rational therapeutic approach for each individual.

Lipids in inflammasome activation and autoinflammatory disorders

Autoinflammatory diseases (AIDs) are a group of rare monogenetic disorders characterized by recurrent episodes of fever and systemic inflammation. A major pathologic hallmark of AIDs is excessive inflammasome assembly and activation, often the result of gain-of-function mutations in genes encoding core inflammasome components, including pyrin and cryopyrin. Recent advances in lipidomics have revealed that dysregulated metabolism of lipids such as cholesterol and fatty acids, especially in innate immune cells, exerts complex effects on inflammasome activation and the pathogenesis of AIDs. In this review, we summarize and discuss the impact of lipids and their metabolism on inflammasome activation and the disease pathogenesis of the most common AIDs, including familial Mediterranean fever, cryopyrin-associated periodic syndromes, and mevalonate kinase deficiency. We postulate that lipids hold diagnostic value in AIDs and that dietary and pharmacologic intervention studies could represent a promising approach to attenuate inflammasome activation and AID progression.

Disrupted balance between pro-inflammatory lipid mediators and anti-inflammatory specialized pro-resolving mediators is linked to hyperinflammation in patients with alcoholic hepatitis

Background

Chronic excessive alcohol consumption leads to a spectrum of alcohol-associated liver diseases (ALD), including alcoholic hepatitis (AH). AH is characterized by intense systemic and liver inflammation, posing significant risks of health complications and mortality. While inflammation is a crucial defense mechanism against injury and infection, its timely resolution is essential to prevent tissue damage and restore tissue homeostasis. The resolution of inflammation is an actively regulated process, primarily governed by specialized pro-resolving mediators (SPMs), lipid metabolites derived from ω-6 and ω-3 poly-unsaturated fatty acids (PUFAs). We investigated the balance between pro-inflammatory lipid mediators (PLMs) and SPMs in the ω-6 and ω-3 PUFA metabolic pathways and examined the impact of alcohol abstinence on rectifying the dysregulated biosynthesis of PLMs and SPMs in AH patients.

Methods

LC-MS/MS and ELISA were used to quantify levels of bioactive lipid mediators (LMs) and their precursors in the plasma samples from 58 AH patients, 29 heavy drinkers without overt liver diseases (HDCs), and 35 healthy controls (HCs). Subsequently, we assessed correlations of altered LMs with clinical parameters and various markers of inflammatory cascade andmicrobial translocation. Furthermore, we conducted a longitudinal study to track changes in levels of LMs over 6- and 12-month follow-ups in AH patients who underwent alcohol abstinence.

Results

AH patients exhibited significantly higher plasma levels of ω-6 PLMs (PGD 2 and LTB 4 ) and SPM RvE1 compared to HDCs and/or HCs. Conversely, key SPMs such as LXA4, RvD1, and several precursors in the ω-3 pathway were significantly downregulated in AH patients. Some of these altered LMs were found to correlate with AH disease severity, clinical parameters, and various inflammatory cytokines. In particular, the LTB4/LXA4 ratio was substantially elevated in AH patients relative to HDCs and HCs. This altered ratio displayed a positive correlation with the MELD score, suggesting its potential utility as an indicator of disease severity in AH patients. Importantly, the majority of dysregulated LMs, particularly PLMs, were normalized following alcohol abstinence.

Conclusion

Our study reveals significant dysregulation in the levels of PLM metabolites and anti-inflammatory SPMs in both ω-6 and ω-3 PUFA pathways in AH patients. This disrupted biosynthesis, characterized by an overabundance of PLMs and a deficiency in SPMs, is linked to the heightened inflammation observed in AH patients. Importantly, our findings suggest an important role of alcohol abstinence in restoring the balance of these LMs and the potential therapeutic benefits of SPM supplements in alleviating the inflammatory cascade in AH patients.

Effect of specialized pro-resolving lipid mediators in the regulation of vascular tone and inflammation in human saphenous vein

Specialized pro-resolving lipid mediators (SPMs), derived from polyunsaturated fatty acids are important mediators in the resolution of inflammation. Recent studies have focused on the effects of SPMs in cardiovascular health and diseases. However, little is known about the effect SPMs on human vascular tone. Therefore, in this study it is aimed to investigate the effect of various SPMs including resolvin D- and E-series, maresin-1 (MaR1) and lipoxin-A4 (LxA4) on the vascular tone of human isolated saphenous vein (SV) preparations under inflammatory conditions. In addition, we aimed to evaluate the effects of SPMs on the release of pro-inflammatory mediators, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF- α) from human SV. Pretreatment of isolated of human SV with resolvin E1 (RvE1), resolvin D1 (RvD1) and MaR1 (100 nM, 18 h) significantly reduced the contractile responses to thromboxane A2 mimetic, U46619 whereas pretreatment with LxA4 and RvD2 (100 nM, 18 h) had no significant effect on the vascular tone of SV. Moreover, RvE1, RvD1 and MaR1 but not LxA4 and RvD2 (100 nM, 18 h) pretreatment diminished the release of MCP-1 and TNF-α from SV. In conclusion, our findings suggest that pre-treatment with RvE1, RvD1, and MaR1 could have potential benefits in decreasing graft vasospasm and vascular inflammation in SV.

1,4-Diaryl-1,2,3-triazole neolignan-celecoxib hybrids inhibit experimental arthritis induced by zymosan

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes cartilage damage. Anti-inflammatories are widely used in the management of RA, but they can have side effects such as gastrointestinal and/or cardiovascular disorders. Studies published by our group showed that the synthesis of hybrid triazole analogs neolignan-celecoxib containing the substituent groups sulfonamide (L15) or carboxylic acid (L18) exhibited anti-inflammatory activity in an acute model of inflammation, inhibited expression of P-selectin related to platelet activation and did not induce gastric ulcer, minimizing the related side effects. In continuation, the present study evaluated the anti-inflammatory effects of these analogs in an experimental model of arthritis and on the functions of one of the important cells in this process, macrophages. Mechanical hyperalgesia, joint edema, leukocyte recruitment to the joint and damage to cartilage in experimental arthritis and cytotoxicity, spread of disease, phagocytic activity and nitric oxide (NO) and hydrogen peroxide production by macrophages were evaluated. Pre-treatment with L15 and L18 reduced mechanical hyperalgesia, joint edema and the influx of leukocytes into the joint cavity after different periods of the stimulus. The histological evaluation of the joint showed that L15 and L18 reduced cartilage damage and there was no formation of rheumatoid pannus. Furthermore, L15 and L18 were non-cytotoxic. The analogs inhibited the spreading, the production of NO and hydrogen peroxide. L15 decreased the phagocytosis. Therefore, L15 and L18 may be potential therapeutic prototypes to treat chronic inflammatory diseases such as RA.

Resolvin D1 Induces mTOR-independent and ATG5-dependent Autophagy in BV-2 Microglial Cells

OBJECTIVE

The activation state of microglia is known to occupy a central position in the pathophysiological process of cerebral inflammation. Autophagy is a catabolic process responsible for maintaining cellular homeostasis. In recent years, autophagy has been demonstrated to play an important role in neuroinflammation. Resolvin D1 (RvD1) is a promising therapeutic mediator that has been shown to exert substantial anti-inflammatory and proresolving activities. However, whether RvD1-mediated resolution of inflammation in microglia is related to autophagy regulation needs further investigation. The present study aimed to explore the effect of RvD1 on microglial autophagy and its corresponding pathways.

METHODS

Mouse microglial cells (BV-2) were cultured, treated with RvD1, and examined by Western blotting, confocal immunofluorescence microscopy, transmission electron microscopy, and flow cytometry.

RESULTS

RvD1 promoted autophagy in both BV-2 cells and mouse primary microglia by favoring the maturation of autophagosomes and their fusion with lysosomes. Importantly, RvD1 had no significant effect on the activation of mammalian target of rapamycin (mTOR) signaling. Furthermore, RvD1-induced mTOR-independent autophagy was confirmed by observing reduced cytoplasmic calcium levels and suppressed calcium/calmodulin-dependent protein kinase II (CaMK II) activation. Moreover, by downregulating ATG5, the increased phagocytic activity induced by RvD1 was demonstrated to be tightly controlled by ATG5-dependent autophagy.

CONCLUSION

The present work identified a previously unreported mechanism responsible for the role of RvD1 in microglial autophagy, highlighting its therapeutic potential against neuroinflammation.

Maresin1 ameliorates MSU crystal-induced inflammation by upregulating Prdx5 expression

BACKGROUND

Maresin1 (MaR1) is a potent lipid mediator that exhibits significant anti-inflammatory activity in the context of several inflammatory diseases. A previous study reported that MaR1 could suppress MSU crystal-induced peritonitis in mice. To date, the molecular mechanism by which MaR1 inhibits MSU crystal-induced inflammation remains poorly understood.

METHODS

Mousebone marrow-derived macrophages (BMDMs) were pretreated with MaR1 and then stimulated with FAs (palmitic, C16:0 and stearic, C18:0) plus MSU crystals (FAs + MSUc). In vivo, the effects of MaR1 treatment or Prdx5 deficiency on MSUc induced peritonitis and arthritis mouse models were evaluated.

RESULTS

The current study indicated that MaR1 effectively suppressed MSUc induced inflammation in vitro and in vivo. MaR1 reversed the decrease in Prdx5 mRNA and protein levels induced by FAs + MSUc. Further assays demonstrated that MaR1 acceleratedPrdx5 expression by regulating the Keap1-Nrf2 signaling axis. Activation of AMPK by Prdx5 improved homeostasis of the TXNIP and TRX proteins and alleviated mitochondrial fragmentation. In addition, Prdx5 overexpression inhibited the expression of CPT1A, a key enzyme for fatty acid oxidation (FAO). Prdx5 protected against defects in FA + MSUc induced FAO and the urea cycle.

CONCLUSION

MaR1 treatment effectively attenuated MSUc induced inflammation by upregulating Prdx5 expression. Our study provides a new strategy by which Prdx5 may help prevent acute gout attacks.

Metabolic influences on T cell in psoriasis: a literature review

Psoriasis is a systemic inflammatory disease that frequently coexists with various other conditions, such as essential hypertension, diabetes, metabolic syndrome, and inflammatory bowel disease. The association between these diseases may be attributed to shared inflammatory pathways and abnormal immunomodulatory mechanisms. Furthermore, metabolites also play a regulatory role in the function of different immune cells involved in psoriasis pathogenesis, particularly T lymphocytes. In this review, we have summarized the current research progress on T cell metabolism in psoriasis, encompassing the regulation of metabolites in glucose metabolism, lipid metabolism, amino acid metabolism, and other pathways within T cells affected by psoriasis. We will also explore the interaction and mechanism between psoriatic metabolites and immune cells. Moreover, we further discussed the research progress of metabolomics in psoriasis to gain a deeper understanding of its pathogenesis and identify potential new therapeutic targets through identification of metabolic biomarkers associated with this condition.

Dynamics of Docosahexaenoic Acid Utilization by Mouse Peritoneal Macrophages

In this work, the incorporation of docosahexaenoic acid (DHA) in mouse resident peritoneal macrophages and its redistribution within the various phospholipid classes were investigated. Choline glycerophospholipids (PC) behaved as the major initial acceptors of DHA. Prolonged incubation with the fatty acid resulted in the transfer of DHA from PC to ethanolamine glycerophospholipids (PE), reflecting phospholipid remodeling. This process resulted in the cells containing similar amounts of DHA in PC and PE in the resting state. Mass spectrometry-based lipidomic analyses of phospholipid molecular species indicated a marked abundance of DHA in ether phospholipids. Stimulation of the macrophages with yeast-derived zymosan resulted in significant decreases in the levels of all DHA-containing PC and PI species; however, no PE or PS molecular species were found to decrease. In contrast, the levels of an unusual DHA-containing species, namely PI(20:4/22:6), which was barely present in resting cells, were found to markedly increase under zymosan stimulation. The levels of this phospholipid also significantly increased when the calcium-ionophore A23187 or platelet-activating factor were used instead of zymosan to stimulate the macrophages. The study of the route involved in the synthesis of PI(20:4/22:6) suggested that this species is produced through deacylation/reacylation reactions. These results define the increases in PI(20:4/22:6) as a novel lipid metabolic marker of mouse macrophage activation, and provide novel information to understand the regulation of phospholipid fatty acid turnover in activated macrophages.

Role of long-chain polyunsaturated fatty acids, eicosapentaenoic and docosahexaenoic, in the regulation of gene expression during the development of obesity: a systematic review

INTRODUCTION

There exists a correlation between obesity and the consumption of an excessive amount of calories, with a particular association between the intake of saturated and trans fats and an elevated body mass index. Omega-3 fatty acids, specifically eicosapentaenoic and docosahexaenoic acids, have been identified as potential preventive nutrients against the cardiometabolic hazards that are commonly associated with obesity. The objective of this comprehensive review was to elucidate the involvement of long-chain polyunsaturated fatty acids, specifically eicosapentaenoic acid and docosahexaenoic acid, in the modulation of gene expression during the progression of obesity.

METHODS

The present analysis focused on primary studies that investigated the association between long-chain polyunsaturated fatty acids, gene expression, and obesity in individuals aged 18 to 65 years. Furthermore, a comprehensive search was conducted on many databases until August 2023 to identify English-language scholarly articles utilizing MeSH terms and textual content pertaining to long-chain polyunsaturated fatty acids, gene expression, obesity, and omega-3. The protocol has been registered on PROSPERO under the registration number CRD42022298395. A comprehensive analysis was conducted on a total of nine primary research articles. All research collected and presented quantitative data.

RESULTS AND DISCUSSION

The findings of our study indicate that the incorporation of eicosapentaenoic and docosahexaenoic acid may have potential advantages and efficacy in addressing noncommunicable diseases, including obesity. This can be attributed to their anti-inflammatory properties and their ability to regulate genes associated with obesity, such as PPARγ and those within the ALOX family.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022298395, CRD42022298395.

Intra-articular bone marrow mononuclear cell therapy improves lameness from naturally occurring equine osteoarthritis

Osteoarthritis (OA) can be debilitating and is related to impaired resolution of synovial inflammation. Current treatments offer temporary relief of clinical signs, but have potentially deleterious side effects. Bone marrow mononuclear cells (BMNC) are a rich source of macrophage progenitors that have the ability to reduce OA symptoms in people and inflammation in experimentally-induced synovitis in horses. The objective of this study was to evaluate the ability of intra-articular BMNC therapy to improve clinical signs of naturally occurring equine OA. Horses presenting with clinical and radiographic evidence of moderate OA in a single joint were randomly assigned to 1 of 3 treatment groups: saline (negative control), triamcinolone (positive control), or BMNC (treatment group). Lameness was evaluated subjectively and objectively, joint circumference measured, and synovial fluid collected for cytology and growth factor/cytokine quantification at 0, 7, and 21 days post-injection. Data were analyzed using General Estimating Equations with significance set at p < 0.05. There were no adverse effects noted in any treatment group. There was a significant increase in synovial fluid total nucleated cell count in the BMNC-treated group on day 7 (median 440; range 20-1920 cells/uL) compared to day 0. Mononuclear cells were the predominant cell type across treatments at all time points. Joint circumference decreased significantly in the BMNC-treated group from days 7 to 21 and was significantly lower at day 21 in the BMNC-treated group compared to the saline-treated group. Median objective lameness improved significantly in the BMNC group between days 7 and 21. GM-CSF, IL-1ra, IGF-1, and TNF-α were below detectable limits and IL-6, IL-1β, FGF-2 were detectable in a limited number of synovial fluid samples. Inconsistent and limited differences were detected over time and between treatment groups for synovial fluid PGE2, SDF-1, MCP-1 and IL-10. Decreased lameness and joint circumference, coupled with a lack of adverse effects following BMNC treatment, support a larger clinical trial using BMNC therapy to treat OA in horses.

Anti-Inflammatory Activity of N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide Derivative via sGC-NO/Cytokine Pathway

The N-acylhydrazone function has been reported as a pharmacophore group of molecules with diverse pharmacological activities, including anti-inflammatory effects. Therefore, this study was designed to evaluate the anti-inflammatory potential of the compound N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide (JR19) in vivo. The study started with the carrageenan-induced peritonitis model, followed by an investigation of leukocyte migration using the subcutaneous air pouch test and an assessment of the antinociceptive profile using formalin-induced pain. A preliminary molecular docking study focusing on the crystallographic structures of NFκB, iNOS, and sGC was performed to determine the likely mechanism of action. The computational study revealed satisfactory interaction energies with the selected targets, and the same peritonitis model was used to validate the involvement of the nitric oxide pathway and cytokine expression in the peritoneal exudate of mice pretreated with L-NAME or methylene blue. In the peritonitis assay, JR19 (10 and 20 mg/kg) reduced leukocyte migration by 59% and 52%, respectively, compared to the vehicle group, with the 10 mg/kg dose used in subsequent assays. In the subcutaneous air pouch assay, the reduction in cell migration was 66%, and the response to intraplantar formalin was reduced by 39%, particularly during the inflammatory phase, suggesting that the compound lacks central analgesic activity. In addition, a reversal of the anti-inflammatory effect was observed in mice pretreated with L-NAME or methylene blue, indicating the involvement of iNOS and sGC in the anti-inflammatory response of JR19. The compound effectively and significantly decreased the levels of IL-6, TNF-α, IL-17, and IFN-γ, and this effect was reversed in animals pretreated with L-NAME, supporting a NO-dependent anti-inflammatory effect. In contrast, pretreatment with methylene blue only reversed the reduction in TNF-α levels. Therefore, these results demonstrate the pharmacological potential of the novel N-acylhydrazone derivative, which acts through the nitric oxide pathway and cytokine signaling, making it a strong candidate as an anti-inflammatory and immunomodulatory agent.

Sterile inflammation and the NLRP3 inflammasome in cardiometabolic disease

Inflammation plays an important role in the pathophysiology of cardiometabolic diseases. Sterile inflammation, a non-infectious and damage-associated molecular pattern (DAMP)-induced innate response, is now well-established to be closely associated with development and progression of cardiometabolic diseases. The NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome is well-established as a major player in sterile inflammatory responses. It is a multimeric cytosolic protein complex which regulates the activation of caspase-1 and subsequently promotes cleavage and release of interleukin (IL)-1 family cytokines, which have a deleterious impact on the development of cardiometabolic diseases. Therefore, targeting NLRP3 itself or the downstream consequences of NLRP3 activation represent excellent potential therapeutic targets in inflammatory cardiometabolic diseases. Here, we review our current understanding of the role which NLRP3 inflammasome regulation plays in cardiometabolic diseases such as obesity, diabetes, non-alcoholic steatohepatitis (NASH), atherosclerosis, ischemic heart disease and cardiomyopathy. Finally, we highlight the potential of targeting NLPR3 or related signaling molecules as a therapeutic approach.

Novel thiazolopyridine derivatives of diflapolin as dual sEH/FLAP inhibitors with improved solubility

Inflammatory responses are orchestrated by a plethora of lipid mediators, and perturbations of their biosynthesis or degradation hinder resolution and lead to uncontrolled inflammation, which contributes to diverse pathologies. Small molecules that induce a switch from pro-inflammatory to anti-inflammatory lipid mediators are considered valuable for the treatment of chronic inflammatory diseases. Commonly used non-steroidal anti-inflammatory drugs (NSAIDs) are afflicted with side effects caused by the inhibition of beneficial prostanoid formation and redirection of arachidonic acid (AA) into alternative pathways. Multi-target inhibitors like diflapolin, the first dual inhibitor of soluble epoxide hydrolase (sEH) and 5-lipoxygenase-activating protein (FLAP), promise improved efficacy and safety but are confronted by poor solubility and bioavailability. Four series of derivatives bearing isomeric thiazolopyridines as bioisosteric replacement of the benzothiazole core and two series additionally containing mono- or diaza-isosteres of the phenylene spacer were designed and synthesized to improve solubility. The combination of thiazolo[5,4-b]pyridine, a pyridinylen spacer and a 3,5-Cl2-substituted terminal phenyl ring (46a) enhances solubility and FLAP antagonism, while preserving sEH inhibition. Moreover, the thiazolo[4,5-c]pyridine derivative 41b, although being a less potent sEH/FLAP inhibitor, additionally decreases thromboxane production in activated human peripheral blood mononuclear cells. We conclude that the introduction of nitrogen, depending on the position, not only enhances solubility and FLAP antagonism (46a), but also represents a valid strategy to expand the scope of application towards inhibition of thromboxane biosynthesis.

Neuropathic pain; what we know and what we should do about it

Neuropathic pain can result from injury to, or disease of the nervous system. It is notoriously difficult to treat. Peripheral nerve injury promotes Schwann cell activation and invasion of immunocompetent cells into the site of injury, spinal cord and higher sensory structures such as thalamus and cingulate and sensory cortices. Various cytokines, chemokines, growth factors, monoamines and neuropeptides effect two-way signalling between neurons, glia and immune cells. This promotes sustained hyperexcitability and spontaneous activity in primary afferents that is crucial for onset and persistence of pain as well as misprocessing of sensory information in the spinal cord and supraspinal structures. Much of the current understanding of pain aetiology and identification of drug targets derives from studies of the consequences of peripheral nerve injury in rodent models. Although a vast amount of information has been forthcoming, the translation of this information into the clinical arena has been minimal. Few, if any, major therapeutic approaches have appeared since the mid 1990's. This may reflect failure to recognise differences in pain processing in males vs. females, differences in cellular responses to different types of injury and differences in pain processing in humans vs. animals. Basic science and clinical approaches which seek to bridge this knowledge gap include better assessment of pain in animal models, use of pain models which better emulate human disease, and stratification of human pain phenotypes according to quantitative assessment of signs and symptoms of disease. This can lead to more personalized and effective treatments for individual patients. Significance statement: There is an urgent need to find new treatments for neuropathic pain. Although classical animal models have revealed essential features of pain aetiology such as peripheral and central sensitization and some of the molecular and cellular mechanisms involved, they do not adequately model the multiplicity of disease states or injuries that may bring forth neuropathic pain in the clinic. This review seeks to integrate information from the multiplicity of disciplines that seek to understand neuropathic pain; including immunology, cell biology, electrophysiology and biophysics, anatomy, cell biology, neurology, molecular biology, pharmacology and behavioral science. Beyond this, it underlines ongoing refinements in basic science and clinical practice that will engender improved approaches to pain management.

NLR family pyrin domain containing 3 (NLRP3) inflammasomes and peripheral neuropathic pain - Emphasis on microRNAs (miRNAs) as important regulators

Neuropathic pain is caused by the lesion or disease of the somatosensory system and can be initiated and/or maintained by both central and peripheral mechanisms. Nerve injury leads to neuronal damage and apoptosis associated with the release of an array of pathogen- or damage-associated molecular patterns to activate inflammasomes. The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome contributes to neuropathic pain and may represent a novel target for pain therapeutic development. In the current review, we provide an up-to-date summary of the recent findings on the involvement of NLRP3 inflammasome in modulating neuropathic pain development and maintenance, focusing on peripheral neuropathic conditions. Here we provide a detailed review of the mechanisms whereby NLRP3 inflammasomes contribute to neuropathic pain via (1) neuroinflammation, (2) apoptosis, (3) pyroptosis, (4) proinflammatory cytokine release, (5) mitochondrial dysfunction, and (6) oxidative stress. We then present the current research literature reporting on the antinociceptive effects of several natural products and pharmacological interventions that target activation, expression, and/or regulation of NLRP3 inflammasome. Furthermore, we emphasize the effects of microRNAs as another regulator of NLRP3 inflammasome. In conclusion, we summarize the possible caveats and future perspectives that might provide successful therapeutic approaches against NLRP3 inflammasome for treating or preventing neuropathic pain conditions.

Efficacy and Safety of Lenabasum, a Cannabinoid Type 2 Receptor Agonist, in a Phase 3 Randomized Trial in Diffuse Cutaneous Systemic Sclerosis

OBJECTIVE

This phase 3 study was undertaken to investigate the efficacy and safety of lenabasum, a cannabinoid type 2 receptor agonist, in patients with diffuse cutaneous systemic sclerosis (dcSSc).

METHODS

A multinational double-blind study was conducted in 365 dcSSc patients who were randomized and dosed 1:1:1 with lenabasum 20 mg, lenabasum 5 mg, or placebo, each twice daily and added to background treatments, including immunosuppressive therapies (IST).

RESULTS

The primary end point, the American College of Rheumatology combined response index in dcSSc (CRISS) at week 52 for lenabasum 20 mg twice a day versus placebo, was not met, with CRISS score of 0.888 versus 0.887 (P = 0.4972, using mixed models repeated measures [MMRM]). The change in the modified Rodnan skin thickness score (MRSS) at week 52 for lenabasum 20 mg twice a day versus placebo was -6.7 versus -8.1 (P = 0.1183, using MMRM). Prespecified analyses showed higher CRISS scores, greater improvement in MRSS, and lower decline in forced vital capacity in patients on background mycophenolate and those who were taking IST for ≤1 year. No deaths or excess in serious or severe adverse events related to lenabasum were observed.

CONCLUSION

A benefit of lenabasum in dcSSc was not demonstrated. Most patients were treated with background IST, and treatment with mycophenolate mofetil in particular was associated with better outcomes. These findings support the use of IST in the treatment of dcSSc and highlight the challenge of demonstrating a treatment effect when investigational treatment is added to standard of care IST. These findings have relevance to trial design in SSc, as well as to clinical care.

Perspective: Council for Responsible Nutrition Science in Session. Optimizing Health with Nutrition-Opportunities, Gaps, and the Future

Achieving optimal health is an aspirational goal for the population, yet the definition of health remains unclear. The role of nutrition in health has evolved beyond correcting malnutrition and specific deficiencies and has begun to focus more on achieving and maintaining 'optimal' health through nutrition. As such, the Council for Responsible Nutrition held its October 2022 Science in Session conference to advance this concept. Here, we summarize and discuss the findings of their Optimizing Health through Nutrition - Opportunities and Challenges workshop, including several gaps that need to be addressed to advance progress in the field. Defining and evaluating various indices of optimal health will require overcoming these key gaps. For example, there is a strong need to develop better biomarkers of nutrient status, including more accurate markers of food intake, as well as biomarkers of optimal health that account for maintaining resilience-the ability to recover from or respond to stressors without loss to physical and cognitive performance. In addition, there is a need to identify factors that drive individualized responses to nutrition, including genotype, metabotypes, and the gut microbiome, and to realize the opportunity of precision nutrition for optimal health. This review outlines hallmarks of resilience, provides current examples of nutritional factors to optimize cognitive and performance resilience, and gives an overview of various genetic, metabolic, and microbiome determinants of individualized responses.

Lipids in major depressive disorder: new kids on the block or old friends revisited?

Major depressive disorder (MDD) is a psychiatric mood disorder that results in substantial functional impairment and is characterized by symptoms such as depressed mood, diminished interest, impaired cognitive function, and vegetative symptoms such as disturbed sleep. Although the exact etiology of MDD is unclear, several underlying mechanisms (disturbances in immune response and/or stress response) have been associated with its development, with no single mechanism able to account for all aspects of the disorder. Currently, about 1 in 3 patients are resistant to current antidepressant therapies. Providing an alternative perspective on MDD could therefore pave the way for new, unexplored diagnostic and therapeutic solutions. The central nervous system harbors an enormous pool of lipids and lipid intermediates that have been linked to a plethora of its physiological functions. The aim of this review is therefore to provide an overview of the implications of lipids in MDD and highlight certain MDD-related underlying mechanisms that involve lipids and/or their intermediates. Furthermore, we will also focus on the bidirectional relationship between MDD and the lipid-related disorders obesity and type 2 diabetes.

The Role of Specialized Pro-Resolving Lipid Mediators in Inflammation-Induced Carcinogenesis

Cancer is a process involving cell mutation, increased proliferation, invasion, and metastasis. Over the years, this condition has represented one of the most concerning health problems worldwide due to its significant morbidity and mortality. At present, the incidence of cancer continues to grow exponentially. Thus, it is imperative to open new avenues in cancer research to understand the molecular changes driving DNA transformation, cell-to-cell interaction derangements, and immune system surveillance decay. In this regard, evidence supports the relationship between chronic inflammation and cancer. In light of this, a group of bioactive lipids derived from polyunsaturated fatty acids (PUFAs) may have a position as novel anti-inflammatory molecules known as the specialized pro-resolving mediators (SPMs), a group of pro-resolutive inflammation agents that could improve the anti-tumor immunity. These molecules have the potential role of chemopreventive and therapeutic agents for various cancer types, and their effects have been documented in the scientific literature. Thus, this review objective centers around understanding the effect of SPMs on carcinogenesis and their potential therapeutic effect.

Ultrasensitive dose-response for asbestos cancer risk implied by new inflammation-mutation model

Alterations in complex cellular phenotype each typically involve multistep activation of an ultrasensitive molecular switch (e.g., to adaptively initiate an apoptosis, inflammasome, Nrf2-ARE anti-oxidant, or heat-shock activation pathway) that triggers expression of a suite of target genes while efficiently limiting false-positive switching from a baseline state. Such switches exhibit nonlinear signal-activation relationships. In contrast, a linear no-threshold (LNT) dose-response relationship is expected for damage that accumulates in proportion to dose, as hypothesized for increased risk of cancer in relation to genotoxic dose according to the multistage somatic mutation/clonal-expansion theory of cancer, e.g., as represented in the Moolgavkar-Venzon-Knudsen (MVK) cancer model by a doubly stochastic nonhomogeneous Poisson process. Mesothelioma and lung cancer induced by exposure to carcinogenic (e.g., certain asbestos) fibers in humans and experimental animals are thought to involve modes of action driven by mutations, cytotoxicity-associated inflammation, or both, rendering ambiguous expectations concerning the nature of model-implied shape of the low-dose response for above-background increase in risk of incurring these endpoints. A recent Inflammation Somatic Mutation (ISM) theory of cancer posits instead that tissue-damage-associated inflammation that epigenetically recruits, activates and orchestrates stem cells to engage in tissue repair does not merely promote cancer, but rather is a requisite co-initiator (acting together with as few as two somatic mutations) of the most efficient pathway to any type of cancer in any reparable tissue (Dose-Response 2019; 17(2):1-12). This theory is reviewed, implications of this theory are discussed in relation to mesothelioma and lung cancer associated with chronic asbestos inhalation, one of the two types of ISM-required mutations is here hypothesized to block or impede inflammation resolution (e.g., by doing so for GPCR-mediated signal transduction by one or more endogenous autacoid specialized pro-resolving mediators or SPMs), and supporting evidence for this hypothesis is discussed.

Inflammation, lipids, and pain in vulvar disease

Localized provoked vulvodynia (LPV) affects ∼14 million people in the US (9% of women), destroying lives and relationships. LPV is characterized by chronic pain (>3 months) upon touch to the vulvar vestibule, which surrounds the vaginal opening. Many patients go months or years without a diagnosis. Once diagnosed, the treatments available only manage the symptoms of disease and do not correct the underlying problem. We have focused on elucidating the underlying mechanisms of chronic vulvar pain to speed diagnosis and improve intervention and management. We determined the inflammatory response to microorganisms, even members of the resident microflora, sets off a chain of events that culminates in chronic pain. This agrees with findings from several other groups, which show inflammation is altered in the painful vestibule. The vestibule of patients is acutely sensitive to inflammatory stimuli to the point of being deleterious. Rather than protect against vaginal infection, it causes heightened inflammation that does not resolve, which coincides with alterations in lipid metabolism that favor production of proinflammatory lipids and not pro-resolving lipids. Lipid dysbiosis in turn triggers pain signaling through the transient receptor potential vanilloid subtype 4 receptor (TRPV4). Treatment with specialized pro-resolving mediators (SPMs) that foster resolution reduces inflammation in fibroblasts and mice and vulvar sensitivity in mice. SPMs, specifically maresin 1, act on more than one part of the vulvodynia mechanism by limiting inflammation and acutely inhibiting TRPV4 signaling. Therefore, SPMs or other agents that target inflammation and/or TRPV4 signaling could prove effective as new vulvodynia therapies.

ALX/FPR2 Activation by Stereoisomers of D1 Resolvins Elucidating with Molecular Dynamics Simulation

Chronic inflammation contributes to several diseases, but its resolution is driven by specialized pro-resolving mediators (SPM) such as resolvin D1 (RvD1) and its epimer aspirin-triggered resolvin D1 (AT-RvD1), both biosynthesized from ω-3 fatty docosahexaenoic acid (DHA). RvD1 and AT-RvD1 have anti-inflammatory and pro-resolution potentials, and their effects could be mediated by formyl peptide receptor type 2 receptor ALX/FPR2, a G-protein-coupled receptor (GPCR). In this work, we performed 44 μs of molecular dynamics simulations with two complexes: FPR2@AT-RvD1 and FPR2@RvD1. Our results show the following: (i) in the AT-RvD1 simulations, the ALX/FPR2 receptor remained in the active state in 62% of the frames, while in the RVD1 simulations, the receptor remained in the active state in 74% of the frames; (ii) two residues, R201 and R205, of ALX/FPR2 appear, establishing interactions with both resolvins in all simulations (22 in total); (iii) RvD1 hydrogen bonds with R201 and R205 presented higher frequency than AT-RvD1; and (iv) residues R201 and R205 are the two receptor hotspots, demonstrated by the binding free calculations. Such results show that the ALX/FPR2 receptor remained in the active state for longer in the FPR2@RvD1 simulations than in the FPR2@AT-RvD1 simulations.

B cell-derived IL-10 promotes the resolution of lipopolysaccharide-induced acute lung injury

Inflammation resolution is critical for acute lung injury (ALI) recovery. Interleukin (IL)-10 is a potent anti-inflammatory factor. However, its role in ALI resolution remains unclear. We investigated the effects of IL-10 during the ALI resolution process in a murine lipopolysaccharide (LPS)-induced ALI model. Blockade of IL-10 signaling aggravates LPS-induced lung injury, as manifested by elevated pro-inflammatory factors production and increased neutrophils recruitment to the lung. Thereafter, we used IL-10 GFP reporter mice to discern the source cell of IL-10 during ALI. We found that IL-10 is predominantly generated by B cells during the ALI recovery process. Furthermore, we used IL-10-specific loss in B-cell mice to elucidate the effect of B-cell-derived IL-10 on the ALI resolution process. IL-10-specific loss in B cells leads to increased pro-inflammatory cytokine expression, persistent leukocyte infiltration, and prolonged alveolar barrier damage. Mechanistically, B cell-derived IL-10 inhibits the activation and recruitment of macrophages and downregulates the production of chemokine KC that recruits neutrophils to the lung. Moreover, we found that IL-10 deletion in B cells leads to alterations in the cGMP-PKG signaling pathway. In addition, an exogenous supply of IL-10 promotes recovery from LPS-induced ALI, and IL-10-secreting B cells are present in sepsis-related ARDS. This study highlights that B cell-derived IL-10 is critical for the resolution of LPS-induced ALI and may serve as a potential therapeutic target.

Myofiber directs macrophages IL-10-Vav1-Rac1 efferocytosis pathway in inflamed muscle following CTX myoinjury by activating the intrinsic TGF-β signaling

BACKGROUND

To explore the role of skeletal muscle specific TGF-β signaling on macrophages efferocytosis in inflamed muscle caused by Cardiotoxin (CTX) injection.

METHODS

CTX myoinjury was manipulated in TGF-βr2^flox/flox (control) mice or transgenic mice with TGF-β receptor 2 (TGF-βr2) being specifically deleted in skeletal muscle (SM TGF-βr2^-/-). Gene levels of TGF-β signal molecules, special inflammatory mediators in damaged muscle or in cultured and differentiated myogenic precursor cells (MPC-myotubes) were monitored by transcriptome microarray or qRT-PCR. TGF-β pathway molecules, myokines and embryonic myosin heavy chain in regenerating myofibers, the phenotype and efferocytosis of macrophages were evaluated by immunofluorescence, immunoblotting, Luminex, or FACS analysis. In vitro apoptotic cells were prepared by UV-irradiation.

RESULTS

In control mice, TGF-β-Smad2/3 signaling were significantly up-regulated in regenerating centronuclear myofibers after CTX-myoinjury. More severe muscle inflammation was caused by the deficiency of muscle TGF-β signaling, with the increased number of M1, but the decreased number of M2 macrophages. Notably, the deficiency of TGF-β signaling in myofibers dramatically affected on the ability of macrophages to conduct efferocytosis, marked by the decreased number of Annexin-V^-F4/80⁺Tunel⁺ macrophages in inflamed muscle, and the impaired uptake of macrophages to PKH67⁺ apoptotic cells transferred into damaged muscle. Further, our study suggested that, the intrinsic TGF-β signaling directed IL-10-Vav1-Rac1 efferocytosis signaling in muscle macrophages.

CONCLUSIONS

Our data demonstrate that muscle inflammation can be suppressed potentially by activating the intrinsic TGF-β signaling in myofibers to promote IL-10 dependent-macrophages efferocytosis. Video Abstract.

Statin and aspirin use in parasitic infections as a potential therapeutic strategy: A narrative review

Infections, including zoonoses, constitute a threat to human health due to the spread of resistant pathogens. These diseases generate an inflammatory response controlled by a resolving mechanism involving specialized membrane lipid-derived molecules called lipoxins, resolvins, maresins, and protectins. The production of some of these molecules can be triggered by aspirin or statins. Thus, it is proposed that modulation of the host response could be a useful therapeutic strategy, contributing to the management of resistance to antiparasitic agents or preventing drift to chronic, host-damaging courses. Therefore, the present work presents the state of the art on the use of statins or aspirin for the experimental management of parasitic infections such as Chagas disease, leishmaniasis, toxoplasmosis or malaria. The methodology used was a narrative review covering original articles from the last seven years, 38 of which met the inclusion criteria. Based on the publications consulted, modulation of the resolution of inflammation using statins may be feasible as an adjuvant in the therapy of parasitic diseases. However, there was no strong experimental evidence on the use of aspirin; therefore, further studies are needed to evaluate its role inflammation resolution process in infectious diseases.

Physical Activity as an Adjunct Treatment for People Living with HIV?

This review evaluates physical activity as a candidate for an adjunct treatment, in conjunction with antiretroviral therapy (ART), for people living with HIV (PLWH). Evidence is summarized that chronic, non-resolving inflammation (a principal feature of immune system dysfunction) and a dysfunctional state of the gut environment are key factors in HIV infection that persist despite treatment with ART. In addition, evidence is summarized that regular physical activity may restore normal function of both the immune system and the gut environment and may thereby ameliorate symptoms and non-resolving inflammation-associated comorbidities that burden PLWH. Physicians who care for PLWH could thus consider incorporating physical activity into treatment plans to complement ART. It is also discussed that different types of physical activity can have different effects on the gut environment and immune function, and that future research should establish more specific criteria for the design of exercise regimens tailored to PLWH.

Inflammation resolution and specialized pro-resolving lipid mediators in chronic rhinosinusitis

INTRODUCTION

In chronic rhinosinusitis (CRS), a complex pathophysiology results from varied pro-inflammatory stimuli but is consistently characterized by classic cellular, molecular, and microbial alterations. Normally, endogenous specialized pro-resolving mediators (SPM) actively promote resolution of inflammation through numerous pathways, including those involved in host antimicrobial defense. However, these pathways appear to be disrupted in CRS.

AREAS COVERED

This paper describes features of CRS in the context of chronic tissue inflammation, and potential mechanisms by which specialized pro-resolving mediators promote active resolution of tissue inflammation.

EXPERT OPINION

Temporal phases of resolution must be tightly regulated to successfully resolve inflammation in CRS while preserving tissue functions such as barrier maintenance and special sensory function. Dysregulation of SPM enzymatic pathways has been recently shown in CRS and is associated with disease phenotypes and microbial colonization patterns. Current research in animal models and in vitro human cell culture, as well as human dietary studies, demonstrate relevant changes in cell signaling with lipid mediator bioavailability. Further clinical research may provide insight into the therapeutic value of this approach in CRS.

The Ying and Yang of Hydrogen Sulfide as a Paracrine/Autocrine Agent in Neurodegeneration: Focus on Amyotrophic Lateral Sclerosis

Ever since its presence was reported in the brain, the nature and role of hydrogen sulfide (H2S) in the Central Nervous System (CNS) have changed. Consequently, H2S has been elected as the third gas transmitter, along with carbon monoxide and nitric oxide, and a number of studies have focused on its neuromodulatory and protectant functions in physiological conditions. The research on H2S has highlighted its many facets in the periphery and in the CNS, and its role as a double-faced compound, switching from protective to toxic depending on its concentration. In this review, we will focus on the bell-shaped nature of H2S as an angiogenic factor and as a molecule released by glial cells (mainly astrocytes) and non-neuronal cells acting on the surrounding environment (paracrine) or on the releasing cells themselves (autocrine). Finally, we will discuss its role in Amyotrophic Lateral Sclerosis, a paradigm of a neurodegenerative disease.

Lipoprotein(a) induces caspase-1 activation and IL-1 signaling in human macrophages

Introduction

Lipoprotein(a) (Lp(a)) is an LDL-like particle with an additional apolipoprotein (apo)(a) covalently attached. Elevated levels of circulating Lp(a) are a risk factor for atherosclerosis. A proinflammatory role for Lp(a) has been proposed, but its molecular details are incompletely defined.

Methods and results

To explore the effect of Lp(a) on human macrophages we performed RNA sequencing on THP-1 macrophages treated with Lp(a) or recombinant apo(a), which showed that especially Lp(a) induces potent inflammatory responses. Thus, we stimulated THP-1 macrophages with serum containing various Lp(a) levels to investigate their correlations with cytokines highlighted by the RNAseq, showing significant correlations with caspase-1 activity and secretion of IL-1β and IL-18. We further isolated both Lp(a) and LDL particles from three donors and then compared their atheroinflammatory potentials together with recombinant apo(a) in primary and THP-1 derived macrophages. Compared with LDL, Lp(a) induced a robust and dose-dependent caspase-1 activation and release of IL-1β and IL-18 in both macrophage types. Recombinant apo(a) strongly induced caspase-1 activation and IL-1β release in THP-1 macrophages but yielded weak responses in primary macrophages. Structural analysis of these particles revealed that the Lp(a) proteome was enriched in proteins associated with complement activation and coagulation, and its lipidome was relatively deficient in polyunsaturated fatty acids and had a high n-6/n-3 ratio promoting inflammation.

Discussion

Our data show that Lp(a) particles induce the expression of inflammatory genes, and Lp(a) and to a lesser extent apo(a) induce caspase-1 activation and IL-1 signaling. Major differences in the molecular profiles between Lp(a) and LDL contribute to Lp(a) being more atheroinflammatory.

Spatially resolved multi-omics highlights cell-specific metabolic remodeling and interactions in gastric cancer

Mapping tumor metabolic remodeling and their spatial crosstalk with surrounding non-tumor cells can fundamentally improve our understanding of tumor biology, facilitates the designing of advanced therapeutic strategies. Here, we present an integration of mass spectrometry imaging-based spatial metabolomics and lipidomics with microarray-based spatial transcriptomics to hierarchically visualize the intratumor metabolic heterogeneity and cell metabolic interactions in same gastric cancer sample. Tumor-associated metabolic reprogramming is imaged at metabolic-transcriptional levels, and maker metabolites, lipids, genes are connected in metabolic pathways and colocalized in the heterogeneous cancer tissues. Integrated data from spatial multi-omics approaches coherently identify cell types and distributions within the complex tumor microenvironment, and an immune cell-dominated "tumor-normal interface" region where tumor cells contact adjacent tissues are characterized with distinct transcriptional signatures and significant immunometabolic alterations. Our approach for mapping tissue molecular architecture provides highly integrated picture of intratumor heterogeneity, and transform the understanding of cancer metabolism at systemic level.

Drinking and laboratory biomarkers, and nutritional status characterize the clinical presentation of early-stage alcohol-associated liver disease

Chronic and heavy alcohol consumption is commonly observed in alcohol use disorder (AUD). AUD often leads to alcohol-associated organ injury, including alcohol-associated liver disease (ALD). Approximately 10-20% of patients with AUD progress to ALD. Progression of ALD from the development phase to more advanced states involve the interplay of several pathways, including nutritional alterations. Multiple pathologic processes have been identified in the progression and severity of ALD. However, there are major gaps in the characterization and understanding of the clinical presentation of early-stage ALD as assessed by clinical markers and laboratory measures. Several Institutions and Universities, including the University of Louisville, in collaboration with the National Institutes of Health, have published a series of manuscripts describing early-stage ALD over the past decade. Here, we comprehensively describe early-stage ALD using the liver injury and drinking history markers, and the laboratory biomarkers (with a focus on nutrition status) that are uniquely involved in the development and progression of early-stage ALD.

Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities

Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.

Mathematical Modeling of Eicosanoid Metabolism in Macrophage Cells: Cybernetic Framework Combined with Novel Information-Theoretic Approaches

Cellular response to inflammatory stimuli leads to the production of eicosanoids—prostanoids (PRs) and leukotrienes (LTs)—and signaling molecules—cytokines and chemokines—by macrophages. Quantitative modeling of the inflammatory response is challenging owing to a lack of knowledge of the complex regulatory processes involved. Cybernetic models address these challenges by utilizing a well-defined cybernetic goal and optimizing a coarse-grained model toward this goal. We developed a cybernetic model to study arachidonic acid (AA) metabolism, which included two branches, PRs and LTs. We utilized a priori biological knowledge to define the branch-specific cybernetic goals for PR and LT branches as the maximization of TNFα and CCL2, respectively. We estimated the model parameters by fitting data from three experimental conditions. With these parameters, we were able to capture a novel fourth independent experimental condition as part of the model validation. The cybernetic model enhanced our understanding of enzyme dynamics by predicting their profiles. The success of the model implies that the cell regulates the synthesis and activity of the associated enzymes, through cybernetic control variables, to accomplish the chosen biological goal. The results indicated that the dominant metabolites are PGD2 (a PR) and LTB4 (an LT), aligning with their corresponding known prominent biological roles during inflammation. Using heuristic arguments, we also infer that eicosanoid overproduction can lead to increased secretion of cytokines/chemokines. This novel model integrates mechanistic knowledge, known biological understanding of signaling pathways, and data-driven methods to study the dynamics of eicosanoid metabolism.

Possibility of averting cytokine storm in SARS-COV 2 patients using specialized pro-resolving lipid mediators

Fatal "cytokine storms (CS)" observed in critically ill COVID-19 patients are consequences of dysregulated host immune system and over-exuberant inflammatory response. Acute respiratory distress syndrome (ARDS), multi-system organ failure, and eventual death are distinctive symptoms, attributed to higher morbidity and mortality rates among these patients. Consequent efforts to save critical COVID-19 patients via the usage of several novel therapeutic options are put in force. Strategically, drugs being used in such patients are dexamethasone, remdesivir, hydroxychloroquine, etc. along with the approved vaccines. Moreover, it is certain that activation of the resolution process is important for the prevention of chronic diseases. Until recently Inflammation resolution was considered a passive process, rather it's an active biochemical process that can be achieved by the use of specialized pro-resolving mediators (SPMs). These endogenous mediators are an array of atypical lipid metabolites that include Resolvins, lipoxins, maresins, protectins, considered as immunoresolvents, but their role in COVID-19 is ambiguous. Recent evidence from studies such as the randomized clinical trial, in which omega 3 fatty acid was used as supplement to resolve inflammation in COVID-19, suggests that direct supplementation of SPMs or the use of synthetic SPM mimetics (which are still being explored) could enhance the process of resolution by regulating the aberrant inflammatory process and can be useful in pain relief and tissue remodeling. Here we discussed the biosynthesis of SPMs, & their mechanistic pathways contributing to inflammation resolution along with sequence of events leading to CS in COVID-19, with a focus on therapeutic potential of SPMs.

The interplay of inflammation, exosomes and Ca2+ dynamics in diabetic cardiomyopathy

Diabetes mellitus is one of the prime risk factors for cardiovascular complications and is linked with high morbidity and mortality. Diabetic cardiomyopathy (DCM) often manifests as reduced cardiac contractility, myocardial fibrosis, diastolic dysfunction, and chronic heart failure. Inflammation, changes in calcium (Ca²⁺) handling and cardiomyocyte loss are often implicated in the development and progression of DCM. Although the existence of DCM was established nearly four decades ago, the exact mechanisms underlying this disease pathophysiology is constantly evolving. Furthermore, the complex pathophysiology of DCM is linked with exosomes, which has recently shown to facilitate intercellular (cell-to-cell) communication through biomolecules such as micro RNA (miRNA), proteins, enzymes, cell surface receptors, growth factors, cytokines, and lipids. Inflammatory response and Ca²⁺ signaling are interrelated and DCM  has been known to adversely affect many of these signaling molecules either qualitatively and/or quantitatively. In this literature review, we have demonstrated that Ca²⁺ regulators are tightly controlled at different molecular and cellular levels during various biological processes in the heart. Inflammatory mediators, miRNA and exosomes are shown to interact with these regulators, however how these mediators are linked to Ca²⁺ handling during DCM pathogenesis remains elusive. Thus, further investigations are needed to understand the mechanisms to restore cardiac Ca²⁺ homeostasis and function, and to serve as potential therapeutic targets in the treatment of DCM.

Sustained release resolvin D1 liposomes are effective in the treatment of osteoarthritis in obese mice

Osteoarthritis (OA) is the most common joint disorder and currently affects >500 million patients worldwide, with ~60% of them also suffering from obesity. There is no drug approved for human use that changes the course of OA progression. OA is one of the most common comorbidities of obesity, and obesity-related OA (ObOA) is a serious health concern because it shows heightened severity of tissue damage and also predominantly affects the working population. Unresolved inflammation is a major driver of ObOA, thus, resolving disease-associated inflammation is a viable strategy to treat ObOA. Resolvins are highly potent molecules that play a role in the resolution of inflammation and promote tissue healing. However, small molecules (like Resolvin D1; RvD1) have to be administered frequently or prior to injury because they lose their in vivo activity rapidly either by lymphatic clearance, or oxidation-mediated deactivation. In this study, we have encapsulated RvD1 in liposomes and established its efficacy in the mouse model of ObOA at much lower dosages than freely administered RvD1. Liposomal RvD1 (lipo-RvD1) acted as a source of the RvD1 molecules for ~11 days in vitro in synovial fluid derived from patients. When administered prophylactically or therapeutically, lipo-RvD1 suppressed cartilage damage in male C57BL/6 mice compared to untreated and free RvD1 treatments. This efficacy was achieved by increasing the proportion of the proresolution M2 macrophages over proinflammatory M1 macrophages in the synovial membrane. These results show the potential of lipo-RvD1 as an anti-OA agent.

Characterization of Arachidonate 5S-Lipoxygenase from Danio rerio with High Activity for the Production of 5S- and 7S-Hydroxy Polyunsaturated Fatty Acids

A recombinant putative lipoxygenase (LOX) from Danio rerio (zebrafish), ALOX3c protein with 6-histidine tag, was purified using affinity chromatography, with a specific activity of 17.2 U mg^-1 for arachidonic acid (AA). The molecular mass of the native ALOX3c was 156 kDa composed of a 78-kDa dimer by gel-filtration chromatography. The product obtained from the conversion of AA was identified as 5S-hydroxyeicosatetraenoic acid (5S-HETE) by HPLC and LC-MS/MS analyses. The specific activity and catalytic efficiency of the LOX from D. rerio for polyunsaturated fatty acids (PUFAs) followed the order AA (17.2 U mg^-1, 1.96 s^-1 μM^-1) > docosahexaenoic acid (DHA, 13.6 U mg^-1, 0.91 s^-1 μM^-1) > eicosapentaenoic acid (EPA, 10.5 U mg^-1, 0.65 s^-1 μM^-1) and these values for AA were the highest among the 5S-LOXs reported to date. Based on identified products and substrate specificity, the enzyme is an AA 5S-LOX. The enzyme exhibited the maximal activity at pH 8.0 and 20 °C with 0.1 mM Zn²⁺ in the presence of 10 mM cysteine. Under these reaction conditions, 6.88 U mL^-1 D. rerio 5S-LOX converted 1.0 mM of AA, EPA, and DHA to 0.91 mM 5S-HETE, 0.72 mM 5S-hydroxyeicosapentaenoic acid (5S-HEPE), and 0.68 mM 7S-hydroxydocosahexaenoic acid (7S-HDHA) in 25, 30, and 25 min, corresponding to molar conversion rates of 91, 72, and 68% and productivities of 2.18, 1.44, and 1.63 mM h^-1, respectively. To the best of our knowledge, this study is the first to describe the bioconversion into 5S-HETE, 5S-HEPE, and 7S-HDHA for the application of biotechnological production.

Resistance to Prostaglandin E2 Promotes Monocyte Activation During Chronic HIV Infection

BACKGROUND

Monocyte activation is a driver of inflammation in the course of chronic HIV infection. Prostaglandin E2 (PGE2) is known to mediate anti-inflammatory effects, notably the inhibition of tumor necrosis factor- (TNF-) production by monocytes. We aim to investigate the effects of PGE2 on activation of monocytes in chronic HIV infection and the mechanisms through which PGE2 modulates their inflammatory signature.

METHODS

We recruited a group of people with HIV (PWH) and matched healthy uninfected persons. We compared plasma levels of PGE2, monocyte activation, and sensitivity of monocytes to the inhibitory actions mediated by PGE2.

RESULTS

We found increased plasma levels of PGE2 in PWH, and an activated phenotype in circulating monocytes, compared with uninfected individuals. Monocytes from PWH showed a significant resistance to the inhibitory actions mediated by PGE2; the concentration of PGE2 able to inhibit 50 of the production of TNF- by lipopolysaccharide-stimulated monocytes was 10 times higher in PWH compared with uninfected controls. Furthermore, the expression of phosphodiesterase 4B, a negative regulator of PGE2 activity, was significantly increased in monocytes from PWH.

CONCLUSIONS

Resistance to the inhibitory actions mediated by PGE2 could account, at least in part, for the inflammatory profile of circulating monocytes in PWH.

Omega-3 Fatty Acids in Cardiovascular Disease and Diabetes: a Review of Recent Evidence

PURPOSE OF REVIEW

Omega-3 fatty acids (n-3 FA) lower triglycerides, have anti-inflammatory properties, and improve metabolism. Clinical evidence of cardiovascular benefit with omega-3 fatty acids is mixed. We discuss mechanisms providing biological plausibility of benefit of omega-3 fatty acids in cardiovascular risk reduction and review clinical trials investigating the benefits of prescription omega-3 fatty acids in dyslipidemia, atherosclerotic cardiovascular disease (ASCVD), and diabetes.

RECENT FINDINGS

Although early trials showed no benefit of omega-3 fatty acids in ASCVD, the REDUCE-IT trial noted significant risk reduction in ASCVD events with highly purified EPA (icosapent ethyl) use which has changed the landscape for currently available therapeutic options. However, other large trials like STRENGTH and VITAL, which used different formulations of prescription omega-3 fatty acids, did not note significant cardiovascular risk reduction. Thus the effectiveness of omega-3 fatty acids for cardiovascular disease prevention is an ongoing topic of debate. A relative paucity of studies examining benefits for glycemic outcomes in persons with diabetes exists; however, few studies have suggested lack of benefit to date. Significant residual cardiovascular risk exists for individuals with hypertriglyceridemia. Prescription omega-3 fatty acids are more commonly used for CV risk reduction in these patients. Clinical guideline statements now recommend icosapent ethyl use for selected individuals with hypertriglyceridemia to reduce cardiovascular events given recent evidence from the REDUCE-IT trial. Nonetheless, data from other large scale trials has been mixed, and future research is needed to better understand how different preparations of omega-3 may differ in their cardiovascular and metabolic effects, and the mechanisms for their benefit.