Docosahexaenoic acid enhances M2 macrophage polarization via the p38 signaling pathway and autophagy

Integrating transcriptomics and metabolomics revealed pathogenic mechanism of Chinese soft-shell turtle (Trionyx sinensis) infected with Trionyx sinensis hemorrhagic syndrome virus (TSHSV)

Trionyx sinensis Hemorrhagic Syndrome Virus(TSHSV)seriously hinders the aquaculture of Chinese soft-shell turtle (Trionyx sinensis) due to its high mortality. However, the pathogenic mechanisms of TSHSV in T. sinensis are still unclear. In present study, transcriptomic and metabolomic analyses were performed on turtle livers following TSHSV infection. 734 up-regulated and 770 down-regulated differentially expressed genes (DEGs) were identified in different TSHSV challenge groups. These DEGs were categorized into 12 pathways related to virus infection and host immunity. Moreover, 27, 2679, and 4341 differentially expressed metabolites (DEMs) were identified in the D1, D3, and D5 groups, respectively. These DEMs were mapped into the pathways of energy metabolism, amino acid metabolism and fatty acid metabolism. Association analysis revealed TSHSV induced inflammatory responses, hepatocyte apoptosis, and ultimately led to liver tissue damage. Taurine supplementation promoted the survival rate of turtle after TSHSV infection and reduced the inflammatory response of liver by regulating the production of interferons, antioxidases, and the pro-inflammatory cytokine TNF-α. Collectively, our results provide comprehensive profiles of the transcriptome and metabolome in Chinese soft-shell turtle liver after TSHSV invasion, shedding light on the underlying pathogenic mechanism. The method of taurine supplementation might be a promising therapeutic strategy for protecting turtles from TSHSV.

Integrated network pharmacology, mass cytometry and multi-omics analysis the effect of Jingfang granule on intestinal immune disorder in mice with cold-dampness syndrome

The pathogenesis of cold-dampness syndrome (CDS) is closely related to intestinal inflammation and immune disorders induced by cold-dampness pathogen. CDS is the root cause of a variety of chronic inflammatory and immune diseases. Jingfang granule (JF) was widely used to treat a variety of diseases closely related to CDS. JF is well known for its clinical effect of dispelling cold and eliminating dampness, but the pharmacological effect and mechanism of JF on the improvement of CDS are still unclear. This study aimed to explore the efficacy and mechanism of JF in improving CDS from the perspective of intestinal immunity. In this study, mass spectrometry (CyTOF), metabolomics, network pharmacology, proteomics and molecular biology experiments were performed to investigate the therapeutic effects and underlying mechanisms of JF on intestinal inflammation and immune disorders in CDS mice. These results showed that JF could improve the clinical symptoms and increase the thymus index of CDS mice. Most strikingly, JF ameliorated intestinal inflammation and immune disorders in CDS mice, as indicated by increased frequency of TH1, CD8 + Tem, CD8 + TEFF, gdT and iNK cells and decreased frequency of Naive B cells, M1-macrophages, DCs and eosinophils. Metabolomics results showed that JF reversed the content of docosahexaenoic acid, arachidonic acid, linoleic acid, inosine and hypoxanthine in CDS mice. Correlation analysis showed that these metabolites were strongly correlated with a variety of intestinal immune cells, indicating that there was a certain regulatory effect between them. Then, 271 JF targets, 316 metabolite targets and 18374 disease targets were integrated to obtain 75 common targets and 138 pathways (such as PI3K/AKT and MAPK pathway, etc). Furthermore, molecular docking, proteomics and western blotting demonstrated that PI3K/AKT signaling pathway might be the key molecular mechanism by which JF regulated intestinal immune disorders in CDS mice. These results suggested that JF may act on the PI3K/AKT pathways to further regulate the levels of metabolites to exert intestinal immunomodulatory effects. In summary, we confirmed the beneficial effects of JF on intestinal immune disorders in CDS mice.

The Impact of Polyunsaturated Fatty Acids in Cancer and Therapeutic Strategies

PURPOSE OF REVIEW

Cancer is a disease influenced by both genetic and environmental factors, with dietary lipids being a significant contributing factor. This review summarizes the role of polyunsaturated fatty acids (PUFAs) in the mechanism of tumor occurrence and development, and elucidate the role of PUFAs in tumor treatment.

RECENT FINDINGS

PUFAs exert their impact on cancer through altering lipid composition in cell membranes, interacting with cell membrane lipid receptors, directly modulating gene expression in the cell nucleus, and participating in the metabolism of lipid mediators. Most omega-3 PUFAs are believed to inhibit cell proliferation, promote cancer cell death, suppress cancer metastasis, alter energy metabolism, inhibit tumor microenvironment inflammation, and regulate immune responses involving macrophages, T cells, NK cells, and others. However, certain omega-6 PUFAs exhibit weaker anti-tumor effects and may even promote tumor development, such as by fostering inflammatory tumor microenvironment and enhancing tumor cell proliferation. PUFAs play important roles in hallmarks of cancer including tumor cell proliferation, cell death, migration and invasion, energy metabolism remodeling, epigenetics, and immunity. These findings provide insights into the mechanisms of cancer development and offers options for dietary management of cancer.

Cell-Type-Specific ROS-AKT/mTOR-Autophagy Interplay-Should It Be Addressed in Periimplantitis?

Periimplantitis represents an inflammatory disease of the soft and hard tissues surrounding the osseointegrated dental implant, triggering progressive damage to the alveolar bone. Cumulative data have revealed that periimplantitis plays a crucial part in implant failure. Due to the strategic roles of autophagy and its upstream coordinator, the AKT/mTOR pathway, in inflammatory responses, the crosstalk between them in the context of periimplantitis should become a key research target, as it opens up an area of interesting data with clinical significance. Therefore, in this article, we aimed to briefly review the existing data concerning the complex roles played by ROS in the interplay between the AKT/mTOR signaling pathway and autophagy in periimplantitis, in each of the main cell types involved in periimplantitis pathogenesis and evolution. Knowing how to modulate specifically the autophagic machinery in each of the cellular types involved in the healing and osseointegration steps post implant surgery can help the clinician to make the most appropriate post-surgery decisions. These decisions might be crucial in order to prevent the occurrence of periimplantitis and ensure the proper conditions for effective osseointegration, depending on patients' clinical particularities.

Reprogramming macrophage metabolism following myocardial infarction: A neglected piece of a therapeutic opportunity

Given the global prevalence of myocardial infarction (MI) as the leading cause of mortality, there is an urgent need to devise novel strategies that target reducing infarct size, accelerating cardiac tissue repair, and preventing detrimental left ventricular (LV) remodeling. Macrophages, as a predominant type of innate immune cells, undergo metabolic reprogramming following MI, resulting in alterations in function and phenotype that significantly impact the progression of MI size and LV remodeling. This article aimed to delineate the characteristics of macrophage metabolites during reprogramming in MI and elucidate their targets and functions in cardioprotection. Furthermore, we summarize the currently proposed regulatory mechanisms of macrophage metabolic reprogramming and identify the regulators derived from endogenous products and natural small molecules. Finally, we discussed the challenges of macrophage metabolic reprogramming in the treatment of MI, with the goal of inspiring further fundamental and clinical research into reprogramming macrophage metabolism and validating its potential therapeutic targets for MI.

Autophagy in Muscle Regeneration: Mechanisms, Targets, and Therapeutic Perspective

Autophagy maintains the stability of eukaryotic cells by degrading unwanted components and recycling nutrients and plays a pivotal role in muscle regeneration by regulating the quiescence, activation, and differentiation of satellite cells. Effective muscle regeneration is vital for maintaining muscle health and homeostasis. However, under certain disease conditions, such as aging, muscle regeneration can fail due to dysfunctional satellite cells. Dysregulated autophagy may limit satellite cell self-renewal, hinder differentiation, and increase susceptibility to apoptosis, thereby impeding muscle regeneration. This review explores the critical role of autophagy in muscle regeneration, emphasizing its interplay with apoptosis and recent advances in autophagy research related to diseases characterized by impaired muscle regeneration. Additionally, we discuss new approaches involving autophagy regulation to promote macrophage polarization, enhancing muscle regeneration. We suggest that utilizing cell therapy and biomaterials to modulate autophagy could be a promising strategy for supporting muscle regeneration. We hope that this review will provide new insights into the treatment of muscle diseases and promote muscle regeneration.

Long-chain polyunsaturated fatty acids influence colorectal cancer progression via the interactions between the intestinal microflora and the macrophages

The metabolism of long-chain polyunsaturated fatty acids (LCPUFAs) is closely associated with the risk and progression of colorectal cancer (CRC). This paper aims to investigate the role of LCPUFA in the crosstalk between intestinal microflora and macrophages, as well as the effects of these three parties on the progression of CRC. The metabolism and function of LCPUFA play important roles in regulating the composition of the human gut microflora and participating in the regulation of inflammation, ultimately affecting macrophage function and polarization, which is crucial in the tumor microenvironment. The effects of LCPUFA on cellular interactions between the two species can ultimately influence the progression of CRC. In this review, we explore the molecular mechanisms and clinical applications of LCPUFA in the interactions between intestinal microflora and intestinal macrophages, as well as its significance for CRC progression. Furthermore, we reveal the role of LCPUFA in the construction of the CRC microenvironment and explore the key nodes of the interactions between intestinal flora and intestinal macrophages in the environment. It provides potential targets for the metabolic diagnosis and treatment of CRC.

ClinOleic Impairs ROS Production and Phagocytosis in M1 Macrophages Without Affecting M1 Differentiation

Lipid emulsions are the primary source of calories and fatty acids that are used to provide essential energy and nutrients to patients suffering from severe intestinal failure and critical illness. However, their use has been linked to adverse effects on patient outcomes, notably affecting immune defenses and inflammatory responses. ClinOleic is a lipid emulsion containing a mixture of olive oil and soybean oil (80:20). The effect of ClinOleic on the differentiation of M1 macrophages remains unclear. In this study, we isolated human monocytes and added ClinOleic to differentiation culture media to investigate whether it affects monocyte polarization into M1 macrophages and macrophage functions, such as reactive oxygen species (ROS) production and phagocytosis. ROS production was stimulated by live S. aureus and detected with L-012, a chemiluminescence emission agent. Phagocytic capacity was assayed using pHrodo™ Green S. aureus Bioparticles® Conjugate. We found that M1 cell morphology, surface markers (CD80 and CD86), and M1-associated cytokines (TNF-α and IL-6) did not significantly change upon incubation with ClinOleic during M1 polarization. However, S. aureus-triggered ROS production was significantly lower in M1 macrophages differentiated with ClinOleic than in those not treated with ClinOleic. The inhibitory effect of ClinOleic on macrophage function also appeared in the phagocytosis assay. Taken together, these findings reveal that ClinOleic has a limited impact on the M1 differentiation phenotype but obviously reduces ROS production and phagocytosis.

Multimodal Imaging-Assisted Intravascular Theranostic Photoactivation on Atherosclerotic Plaque

BACKGROUND

Atherosclerosis is a chronic inflammatory disease causing a fatal plaque rupture, and its key aspect is a failure to resolve inflammation. We hypothesize that macrophage-targeted near-infrared fluorescence emitting photoactivation could simultaneously assess macrophage/lipid-rich plaques in vivo and facilitate inflammation resolution.

METHODS

We fabricated a Dectin-1-targeted photoactivatable theranostic agent through the chemical conjugation of the near-infrared fluorescence-emitting photosensitizer chlorin e6 and the Dectin-1 ligand laminarin (laminarin-chlorin e6 [LAM-Ce6]). Intravascular photoactivation by a customized fiber-based diffuser after administration of LAM-Ce6 effectively reduced inflammation in the targeted plaques of atherosclerotic rabbits in vivo as serially assessed by dual-modal optical coherence tomography-near-infrared fluorescence structural-molecular catheter imaging after 4 weeks.

RESULTS

The number of apoptotic macrophages peaked at 1 day after laser irradiation and then resolved until 4 weeks. Autophagy was strongly augmented 1 hour after the light therapy, with the formation of autophagolysosomes. LAM-Ce6 photoactivation increased the terminal deoxynucleotidyl transferase dUTP (deoxyuridine triphosphate) nick end labeling/RAM11 (rabbit monocyte/macrophage antibody)- and MerTK (c-Mer tyrosine kinase)-positive cells in the plaques, suggesting enhanced efferocytosis. In line with inflammation resolution, photoactivation reduced the plaque burden through fibrotic replacement via the TGF (transforming growth factor)-β/CTGF (connective tissue growth factor) pathway.

CONCLUSIONS

Optical coherence tomography-near-infrared fluorescence imaging-guided macrophage Dectin-1-targetable photoactivation could induce the transition of macrophage/lipid-rich plaques into collagen-rich lesions through autophagy-mediated inflammation resolution and TGF-β-dependent fibrotic replacement. This novel strategy offers a new opportunity for the catheter-based theranostic strategy.

Stimulus-response signaling dynamics characterize macrophage polarization states

The functional state of cells is dependent on their microenvironmental context. Prior studies described how polarizing cytokines alter macrophage transcriptomes and epigenomes. Here, we characterized the functional responses of 6 differentially polarized macrophage populations by measuring the dynamics of transcription factor nuclear factor κB (NF-κB) in response to 8 stimuli. The resulting dataset of single-cell NF-κB trajectories was analyzed by three approaches: (1) machine learning on time-series data revealed losses of stimulus distinguishability with polarization, reflecting canalized effector functions. (2) Informative trajectory features driving stimulus distinguishability ("signaling codons") were identified and used for mapping a cell state landscape that could then locate macrophages conditioned by an unrelated condition. (3) Kinetic parameters, inferred using a mechanistic NF-κB network model, provided an alternative mapping of cell states and correctly predicted biochemical findings. Together, this work demonstrates that a single analyte's dynamic trajectories may distinguish the functional states of single cells and molecular network states underlying them. A record of this paper's transparent peer review process is included in the supplemental information.

Macrophages in CRSwNP: Do they deserve more attention?

Chronic rhinosinusitis (CRS) represents a heterogeneous disorder primarily characterized by the persistent inflammation of the nasal cavity and paranasal sinuses. The subtype known as chronic rhinosinusitis with nasal polyposis (CRSwNP) is distinguished by a significantly elevated recurrence rate and augmented challenges in the management of nasal polyps. The pathogenesis underlying this subtype remains incompletely understood. Macrophages play a crucial role in mediating the immune system's response to inflammatory stimuli. These cells exhibit remarkable plasticity and heterogeneity, differentiating into either the pro-inflammatory M1 phenotype or the anti-inflammatory and reparative M2 phenotype depending on the surrounding microenvironment. In CRSwNP, macrophages demonstrate reduced production of Interleukin 10 (IL-10), compromised phagocytic activity, and decreased autophagy. Dysregulation of pro-resolving mediators may occur during the inflammatory resolution process, which could potentially hinder the adequate functioning of anti-inflammatory macrophages in facilitating resolution. Collectively, these factors may contribute to the prolonged inflammation observed in CRSwNP. Additionally, macrophages may enhance fibrin cross-linking through the release of factor XIII-A (FAXIII), promoting fibrin deposition and plasma protein retention. Macrophages also modulate vascular permeability by releasing Vascular endothelial growth factor (VEGF). Moreover, they may disrupt the balance between Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Metalloproteinases (TIMPs), which favors extracellular matrix (ECM) degradation, edema formation, and pseudocyst development. Accumulating evidence suggests a close association between macrophage infiltration and CRSwNP; however, the precise mechanisms underlying this relationship warrant further investigation. In different subtypes of CRSwNP, different macrophage phenotypic aggregations trigger different types of inflammatory features. Increasing evidence suggests that macrophage infiltration is closely associated with CRSwNP, but the mechanism and the relationship between macrophage typing and CRSwNP endophenotyping remain to be further explored. This review discusses the role of different types of macrophages in the pathogenesis of different types of CRSwNP and their contribution to polyp formation, in the hope that a better understanding of the role of macrophages in specific CRSwNP will contribute to a precise and individualized understanding of the disease.

The role of autophagy and macrophage polarization in the processes of chronic inflammation and regeneration

The cause of many seriousillnesses, including diabetes, obesity, osteoporosis and neurodegenerative diseases is chronic inflammation that develops in adipose tissue, bones or the brain. This inflammation occurs due to a shift in the polarization of macrophages/microglia towards the pro-inflammatory phenotype M1. It has now been proven that the polarization of macrophages is determined by the intracellular level of autophagy in the macrophage. By modulating autophagy, it is possible to cause switching of macrophage activities towards M1 or M2. Summarizing the material accumulated in the literature, we believe that the activation of autophagy reprograms the macrophage towards M2, replacing its protein content, receptor apparatus and including a different type of metabolism. The term reprogramming is most suitable for this process, since it is followed by a change in the functional activity of the macrophage, namely, switching from cytotoxic pro-inflammatory activity to anti-inflammatory (regenerative). Modulation of autophagy can be an approach to the treatment of oncological diseases, neurodegenerative disorders, osteoporosis, diabetes and other serious diseases.

Recent advances in molecular mechanisms of skin wound healing and its treatments

The skin, being a multifaceted organ, performs a pivotal function in the complicated wound-healing procedure, which encompasses the triggering of several cellular entities and signaling cascades. Aberrations in the typical healing process of wounds may result in atypical scar development and the establishment of a persistent condition, rendering patients more vulnerable to infections. Chronic burns and wounds have a detrimental effect on the overall quality of life of patients, resulting in higher levels of physical discomfort and socio-economic complexities. The occurrence and frequency of prolonged wounds are on the rise as a result of aging people, hence contributing to escalated expenditures within the healthcare system. The clinical evaluation and treatment of chronic wounds continue to pose challenges despite the advancement of different therapeutic approaches. This is mainly owing to the prolonged treatment duration and intricate processes involved in wound healing. Many conventional methods, such as the administration of growth factors, the use of wound dressings, and the application of skin grafts, are used to ease the process of wound healing across diverse wound types. Nevertheless, these therapeutic approaches may only be practical for some wounds, highlighting the need to advance alternative treatment modalities. Novel wound care technologies, such as nanotherapeutics, stem cell treatment, and 3D bioprinting, aim to improve therapeutic efficacy, prioritize skin regeneration, and minimize adverse effects. This review provides an updated overview of recent advancements in chronic wound healing and therapeutic management using innovative approaches.

Relevant Aspects of Combined Protocols for Prevention of N(M)AFLD and Other Non-Communicable Diseases

Obesity is a global health issue characterized by the excessive fat accumulation, leading to an increased risk of chronic noncommunicable diseases (NCDs), including metabolic dysfunction-associated fatty liver disease (MAFLD), which can progress from simple steatosis to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Currently, there are no approved pharmacological protocols for prevention/treatment of MAFLD, and due the complexity lying beneath these mechanisms, monotherapies are unlikely to be efficacious. This review article analyzes the possibility that NCDs can be prevented or attenuated by the combination of bioactive substances, as they could promote higher response rates, maximum reaction results, additive or synergistic effects due to compounds having similar or different mechanisms of action and/or refraining possible side effects, related to the use of lower doses and exposures times than monotherapies. Accordingly, prevention of mouse MAFLD is observed with the combination of the omega-3 docosahexaenoic acid with the antioxidant hydroxytyrosol, whereas attenuation of mild cognitive impairment is attained by folic acid plus cobalamin in elderly patients. The existence of several drawbacks underlying published monotherapies or combined trials, opens space for adequate and stricter experimental and clinical tryouts to achieve meaningful outcomes with human applicability.

Autophagy-modulating biomaterials: multifunctional weapons to promote tissue regeneration

Autophagy is a self-renewal mechanism that maintains homeostasis and can promote tissue regeneration by regulating inflammation, reducing oxidative stress and promoting cell differentiation. The interaction between biomaterials and tissue cells significantly affects biomaterial-tissue integration and tissue regeneration. In recent years, it has been found that biomaterials can affect various processes related to tissue regeneration by regulating autophagy. The utilization of biomaterials in a controlled environment has become a prominent approach for enhancing the tissue regeneration capabilities. This involves the regulation of autophagy in diverse cell types implicated in tissue regeneration, encompassing the modulation of inflammatory responses, oxidative stress, cell differentiation, proliferation, migration, apoptosis, and extracellular matrix formation. In addition, biomaterials possess the potential to serve as carriers for drug delivery, enabling the regulation of autophagy by either activating or inhibiting its processes. This review summarizes the relationship between autophagy and tissue regeneration and discusses the role of biomaterial-based autophagy in tissue regeneration. In addition, recent advanced technologies used to design autophagy-modulating biomaterials are summarized, and rational design of biomaterials for providing controlled autophagy regulation via modification of the chemistry and surface of biomaterials and incorporation of cells and molecules is discussed. A better understanding of biomaterial-based autophagy and tissue regeneration, as well as the underlying molecular mechanisms, may lead to new possibilities for promoting tissue regeneration. Video Abstract.

Function and inhibition of P38 MAP kinase signaling: Targeting multiple inflammation diseases

Inflammation is a natural host defense mechanism that protects the body from pathogenic microorganisms. A growing body of research suggests that inflammation is a key factor in triggering other diseases (lung injury, rheumatoid arthritis, etc.). However, there is no consensus on the complex mechanism of inflammatory response, which may include enzyme activation, mediator release, and tissue repair. In recent years, p38 MAPK, a member of the MAPKs family, has attracted much attention as a central target for the treatment of inflammatory diseases. However, many p38 MAPK inhibitors attempting to obtain marketing approval have failed at the clinical trial stage due to selectivity and/or toxicity issues. In this paper, we discuss the mechanism of p38 MAPK in regulating inflammatory response and its key role in major inflammatory diseases and summarize the synthetic or natural products targeting p38 MAPK to improve the inflammatory response in the last five years, which will provide ideas for the development of novel clinical anti-inflammatory drugs based on p38 MAPK inhibitors.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Omega-3 Lipid Mediators: Modulation of the M1/M2 Macrophage Phenotype and Its Protective Role in Chronic Liver Diseases

The complex interplay between dietary factors, inflammation, and macrophage polarization is pivotal in the pathogenesis and progression of chronic liver diseases (CLDs). Omega-3 fatty acids (FAs) have brought in attention due to their potential to modulate inflammation and exert protective effects in various pathological conditions. Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown promise in mitigating inflammation and enhancing the resolution of inflammatory responses. They influence the M1/M2 macrophage phenotype balance, promoting a shift towards the M2 anti-inflammatory phenotype. Specialized pro-resolving mediators (SPMs), such as resolvins (Rvs), protectins (PDs), and maresins (MaRs), have emerged as potent regulators of inflammation and macrophage polarization. They show anti-inflammatory and pro-resolving properties, by modulating the expression of cytokines, facilitate the phagocytosis of apoptotic cells, and promote tissue repair. MaR1, in particular, has demonstrated significant hepatoprotective effects by promoting M2 macrophage polarization, reducing oxidative stress, and inhibiting key inflammatory pathways such as NF-κB. In the context of CLDs, such as nonalcoholic fatty liver disease (NAFLD) and cirrhosis, omega-3s and their SPMs have shown promise in attenuating liver injury, promoting tissue regeneration, and modulating macrophage phenotypes. The aim of this article was to analyze the emerging role of omega-3 FAs and their SPMs in the context of macrophage polarization, with special interest in the mechanisms underlying their effects and their interactions with other cell types within the liver microenvironment, focused on CLDs and the development of novel therapeutic strategies.

Omega-3 Polyunsaturated Fatty Acid Eicosapentaenoic Acid or Docosahexaenoic Acid Improved Ageing-Associated Cognitive Decline by Regulating Glial Polarization

Neuroinflammation induced by microglial and astrocyte polarizations may contribute to neurodegeneration and cognitive impairment. Omega (n)-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory and neuroprotective effects, but conflicting results were reported after different n-3 PUFA treatments. This study examined both the change in glial polarizations in ageing rats and the differential effects of two omega-3 PUFAs. The results showed that both PUFAs improved spatial memory in ageing rats, with docosahexaenoic acid (DHA) being more effective than eicosapentaenoic acid (EPA). The imbalance between microglial M1/M2 polarizations, such as up-regulating ionized calcium binding adaptor molecule 1 (IBA1) and down-regulating CD206 and arginase-1 (ARG-1) was reversed in the hippocampus by both n-3 PUFAs, while the DHA effect on CD206 was stronger. Astrocyte A1 polarization presented increasing S100B and C3 but decreasing A2 parameter S100A10 in the ageing brain, which were restored by both PUFAs, while DHA was more effective on S100A10 than EPA. Consistent with microglial M1 activation, the concentration of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were significantly increased, which were attenuated by DHA, while EPA only suppressed IL-6. In correlation with astrocyte changes, brain-derived neurotrophic factor precursor was increased in ageing rats, which was more powerfully down-regulated by DHA than EPA. In summary, enhanced microglial M1 and astrocytic A1 polarizations may contribute to increased brain pro-inflammatory cytokines, while DHA was more powerful than EPA to alleviate ageing-associated neuroimmunological changes, thereby better-improving memory impairment.

Inhibition of IL-4/STAT6/IRF4 signaling reduces the epithelial-mesenchymal transition in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Previous studies have shown that epithelial-to-mesenchymal transition (EMT) in nasal epithelial cells is critical for tissue remodeling of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the precise mechanism underlying the EMT remains poorly understood. This study aimed to investigate the role of interleukin-4 (IL-4)/signal transducer and activator of transcription 6 (STAT6)/interferon regulatory factor 4 (IRF4) signaling pathway on EMT in eosinophilic CRSwNP.

METHODS

We performed quantitative real-time polymerase chain reaction, immunohistochemistry, immunofluorescent staining, and Western blotting to evaluate the expression of STAT6, IRF4, and EMT markers in sinonasal mucosal samples. Effects of IL-4-induced EMT were determined using primary human nasal epithelial cells (hNECs) from patients with eosinophilic CRSwNP. Wound scratch assay, cell morphology, Western blotting, and immunofluorescence cytochemistry were performed to evaluate EMT, and EMT-related markers. Next, human THP-1 monocytic cells were stimulated by phorbolate-12-myristate-13-acetate to differentiate into M0 and were subsequently polarized into M1 with lipopolysaccharide and interferon-γ, M2 with IL-4. The markers of the macrophage phenotype were assessed by Western blotting. The co-culture system was built to explore the interaction between macrophages (THP-1 cells) and hNECs. After co-culture with M2 macrophages, EMT-related markers of primary hNECs were evaluated by immunofluorescence cytochemistry and Western blotting. Enzymelinked immunosorbent assays were used to detect transforming growth factor beta 1 (TGF-β1) in THP-1-derived supernatants.

RESULTS

STAT6 and IRF4 mRNA and protein expression were significantly upregulated in both eosinophilic and noneosinophilic nasal polyps compared with control tissues. The expression of STAT6 and IRF4 in eosinophilic nasal polyps was higher than those in noneosinophilic nasal polyps. STAT6 and IRF4 were not only expressed in epithelial cells but also in macrophages. The number of STAT6⁺CD68⁺ cells and IRF4⁺CD68⁺ cells in eosinophilic nasal polyps was higher than those in noneosinophilic nasal polyps and control tissues. EMT was enhanced in eosinophilic CRSwNP compared to the healthy controls and noneosinophilic CRSwNP. IL-4-stimulated human nasal epithelial cells exhibited EMT characteristics. The hNECs co-cultured with M2 macrophages demonstrated high levels of EMT-related markers. The TGF-β1 level was significantly induced by IL-4 and elevated (M2) rather than control macrophages. The inhibition of STAT6 by AS1517499 reduced the expression of IRF4 in epithelial cells and macrophages and counteracted IL-4-induced EMT in epithelial cells.

CONCLUSION

In eosinophilic nasal polyps, IL-4 induces STAT6 signaling to upregulate IRF4 expression in epithelial cells and macrophages. IL-4 promotes EMT of hNECs through the STAT6/IRF4 signaling pathway. IL-4-induced M2 macrophages enhanced EMT of hNECs. Inhibition of STAT6 can downregulate the expression of IRF4 and suppress the EMT process, thus providing a new strategy for the treatment of nasal polyps.

Prevention of Chronic Morbidities in Extremely Premature Newborns with LISA-nCPAP Respiratory Therapy and Adjuvant Perinatal Strategies

Less invasive surfactant administration techniques, together with nasal continuous airway pressure (LISA-nCPAP) ventilation, an emerging noninvasive ventilation (NIV) technique in neonatology, are gaining more significance, even in extremely premature newborns (ELBW), under 27 weeks of gestational age. In this review, studies on LISA-nCPAP are compiled with an emphasis on short- and long-term morbidities associated with prematurity. Several perinatal preventative and therapeutic investigations are also discussed in order to start integrated therapies as numerous organ-saving techniques in addition to lung-protective ventilations. Two thirds of immature newborns can start their lives on NIV, and one third of them never need mechanical ventilation. With adjuvant intervention, these ratios are expected to be increased, resulting in better outcomes. Optimized cardiopulmonary transition, especially physiologic cord clamping, could have an additively beneficial effect on patient outcomes gained from NIV. Organ development and angiogenesis are strictly linked not only in the immature lung and retina, but also possibly in the kidney, and optimized interventions using angiogenic growth factors could lead to better morbidity-free survival. Corticosteroids, caffeine, insulin, thyroid hormones, antioxidants, N-acetylcysteine, and, moreover, the immunomodulatory components of mother's milk are also discussed as adjuvant treatments, since immature newborns deserve more complex neonatal interventions.

Role of endoplasmic reticulum autophagy in acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), the prime causes of morbidity and mortality in critically ill patients, are usually treated by general supportive treatments. Endoplasmic reticulum autophagy (ER-phagy) maintains cellular homeostasis by degrading damaged endoplasmic reticulum (ER) fragments and misfolded proteins. ER-phagy is crucial for maintaining ER homeostasis and improving the internal environment. ER-phagy has a particular role in some aspects, such as immunity, inflammation, cell death, pathogen infection, and collagen quality. In this review, we summarized the definition, epidemiology, and pathophysiology of ALI/ARDS and described the regulatory mechanisms and functions of ER-phagy as well as discussed the potential role of ER-phagy in ALI/ARDS from the perspectives of immunity, inflammation, apoptosis, pathogen infection, and fibrosis to provide a novel and effective target for improving the prognosis of ALI/ARDS.

Distinct Responses to IL4 in Macrophages Mediated by JNK

IL(Interleukin)-4 is the main macrophage M2-type activator and induces an anti-inflammatory phenotype called alternative activation. The IL-4 signaling pathway involves the activation of STAT (Signal Transducer and Activator of Transcription)-6 and members of the MAPK (Mitogen-activated protein kinase) family. In primary-bone-marrow-derived macrophages, we observed a strong activation of JNK (Jun N-terminal kinase)-1 at early time points of IL-4 stimulation. Using selective inhibitors and a knockout model, we explored the contribution of JNK-1 activation to macrophages' response to IL-4. Our findings indicate that JNK-1 regulates the IL-4-mediated expression of genes typically involved in alternative activation, such as Arginase 1 or Mannose receptor, but not others, such as SOCS (suppressor of cytokine signaling) 1 or p21^Waf-1 (cyclin dependent kinase inhibitor 1A). Interestingly, we have observed that after macrophages are stimulated with IL-4, JNK-1 has the capacity to phosphorylate STAT-6 on serine but not on tyrosine. Chromatin immunoprecipitation assays revealed that functional JNK-1 is required for the recruitment of co-activators such as CBP (CREB-binding protein)/p300 on the promoter of Arginase 1 but not on p21^Waf-1. Taken together, these data demonstrate the critical role of STAT-6 serine phosphorylation by JNK-1 in distinct macrophage responses to IL-4.

Selective ischemic-hemisphere targeting Ginkgolide B liposomes with improved solubility and therapeutic efficacy for cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury (CI/RI) remains the main cause of disability and death in stroke patients due to lack of effective therapeutic strategies. One of the main issues related to CI/RI treatment is the presence of the blood-brain barrier (BBB), which affects the intracerebral delivery of drugs. Ginkgolide B (GB), a major bioactive component in commercially available products of Ginkgo biloba, has been shown significance in CI/RI treatment by regulating inflammatory pathways, oxidative damage, and metabolic disturbance, and seems to be a candidate for stroke recovery. However, limited by its poor hydrophilicity and lipophilicity, the development of GB preparations with good solubility, stability, and the ability to cross the BBB remains a challenge. Herein, we propose a combinatorial strategy by conjugating GB with highly lipophilic docosahexaenoic acid (DHA) to obtain a covalent complex GB-DHA, which can not only enhance the pharmacological effect of GB, but can also be encapsulated in liposomes stably. The amount of finally constructed Lipo@GB-DHA targeting to ischemic hemisphere was validated 2.2 times that of free solution in middle cerebral artery occlusion (MCAO) rats. Compared to the marketed ginkgolide injection, Lipo@GB-DHA significantly reduced infarct volume with better neurobehavioral recovery in MCAO rats after being intravenously administered both at 2 h and 6 h post-reperfusion. Low levels of reactive oxygen species (ROS) and high neuron survival in vitro was maintained via Lipo@GB-DHA treatment, while microglia in the ischemic brain were polarized from the pro-inflammatory M1 phenotype to the tissue-repairing M2 phenotype, which modulate neuroinflammatory and angiogenesis. In addition, Lipo@GB-DHA inhibited neuronal apoptosis via regulating the apoptotic pathway and maintained homeostasis by activating the autophagy pathway. Thus, transforming GB into a lipophilic complex and loading it into liposomes provides a promising nanomedicine strategy with excellent CI/RI therapeutic efficacy and industrialization prospects.

Macrophage autophagy in macrophage polarization, chronic inflammation and organ fibrosis

As the essential regulators of organ fibrosis, macrophages undergo marked phenotypic and functional changes after organ injury. These changes in macrophage phenotype and function can result in maladaptive repair, causing chronic inflammation and the development of pathological fibrosis. Autophagy, a highly conserved lysosomal degradation pathway, is one of the major players to maintain the homeostasis of macrophages through clearing protein aggregates, damaged organelles, and invading pathogens. Emerging evidence has shown that macrophage autophagy plays an essential role in macrophage polarization, chronic inflammation, and organ fibrosis. Because of the high heterogeneity of macrophages in different organs, different macrophage types may play different roles in organ fibrosis. Here, we review the current understanding of the function of macrophage autophagy in macrophage polarization, chronic inflammation, and organ fibrosis in different organs, highlight the potential role of macrophage autophagy in the treatment of fibrosis. Finally, the important unresolved issues in this field are briefly discussed. A better understanding of the mechanisms that macrophage autophagy in macrophage polarization, chronic inflammation, and organ fibrosis may contribute to developing novel therapies for chronic inflammatory diseases and organ fibrosis.

Autophagy Plays Multiple Roles in the Soft-Tissue Healing and Osseointegration in Dental Implant Surgery-A Narrative Review

Dental endo-osseous implants have become a widely used treatment for replacing missing teeth. Dental implants are placed into a surgically created osteotomy in alveolar bone, the healing of the soft tissue lesion and the osseointegration of the implant being key elements to long-term success. Autophagy is considered the major intracellular degradation system, playing important roles in various cellular processes involved in dental implant integration. The aim of this review is an exploration of autophagy roles in the main cell types involved in the healing and remodeling of soft tissue lesions and implant osseointegration, post-implant surgery. We have focused on the autophagy pathway in macrophages, endothelial cells; osteoclasts, osteoblasts; fibroblasts, myofibroblasts and keratinocytes. In macrophages, autophagy modulates innate and adaptive immune responses playing a key role in osteo-immunity. Autophagy induction in endothelial cells promotes apoptosis resistance, cell survival, and protection against oxidative stress damage. The autophagic machinery is also involved in transporting stromal vesicles containing mineralization-related factors to the extracellular matrix and regulating osteoblasts' functions. Alveolar bone remodeling is achieved by immune cells differentiation into osteoclasts; autophagy plays an important and active role in this process. Autophagy downregulation in fibroblasts induces apoptosis, leading to better wound healing by improving excessive deposition of extracellular matrix and inhibiting fibrosis progression. Autophagy seems to be a dual actor on the scene of dental implant surgery, imposing further research in order to completely reveal its positive features which may be essential for clinical efficacy.

Progress in preclinical studies of macrophage autophagy in the regulation of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality that poses a major challenge in critical care medicine. The development of ALI/ARDS involves excessive inflammatory response, and macrophage autophagy plays an important role in regulating the inflammatory response in ALI/ARDS. In this paper, we review the effects of autophagy in regulating macrophage function, discuss the roles of macrophage autophagy in ALI/ARDS, and highlight drugs and other interventions that can modulate macrophage autophagy in ALI/ARDS to improve the understanding of the mechanism of macrophage autophagy in ALI/ARDS and provide new ideas and further research directions for the treatment of ALI/ARDS.

Eucalyptol prevents bleomycin-induced pulmonary fibrosis and M2 macrophage polarization

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial pneumonia with limited therapeutic options. Eucalyptol, a terpenoid oxide isolated from eucalyptus species, reportedly exhibits various biological activities such as anti-inflammatory and antioxidant effects. In the present study, we aimed to determine whether eucalyptol could alleviate bleomycin (BLM)-induced pulmonary fibrosis and inhibit interleukin (IL)-13-induced M2 macrophage polarization. Upon treatment with eucalyptol, BLM-induced pulmonary fibrosis and lung inflammation were significantly reduced. The pulmonary neutrophil accumulation and pulmonary permeability were inhibited and the expression of hydroxyproline, alpha-smooth muscle actin, and fibronectin was significantly down-regulated. Eucalyptol also markedly inhibited the expression of arginase-1, Ym-1, IL-13, and transforming growth factor (TGF)-β1, reduced the production of IL-13, IL-6, tumor necrosis factor (TNF)-α, and attenuated the activity of TGF-β1 in bronchoalveolar lavage fluid (BALF). Furthermore, the in vitro assay revealed that eucalyptol disturbed M2 macrophage polarization and reduced the macrophage-mediated secretion of the profibrotic factor TGF-β1. Eucalyptol inhibited the nuclear location of signal transducer and activator of transcription 6 (STAT6) and the phosphorylation of STAT6 and p38 mitogen-activated protein kinase (p38 MAPK), and reduced the expression of their downstream transcription factors, krupple-like factor 4 (KLF4) and peroxisome proliferator-activated receptor gamma (PPAR-γ). These findings indicated that eucalyptol alleviates BLM-induced pulmonary fibrosis by regulating M2 macrophage polarization, which, in turn, inhibits the activation of signaling molecules (e.g., STAT6 and p38 MAPK) and the expression of transcription factors (e.g., KLF4 and PPAR-γ). Thus, eucalyptol might be a potential therapeutic agent for IPF.

CC chemokine receptor 7 promotes macrophage recruitment and induces M2-polarization through CC chemokine ligand 19&21 in oral squamous cell carcinoma

PURPOSE

This study aimed to investigate the impact of CC chemokine receptor 7 (CCR7) on the recruitment and polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC).

METHODS

We analyzed CCR7 expression pattern, clinicopathological significance, and its association with M2 macrophage infiltration in OSCC by bioinformatic methods. Small interfering RNA (siRNA) was utilized to silence CCR7 in OSCC cells. Conditioned media (CM) was harvested from transfected OSCC cells to establish a co-culture model of THP-1 derived macrophages and OSCC cells. Transwell assay and cell adhesion assay were performed to examine the effect of CCR7 on macrophages recruitment and adhesion. Cytoskeleton was labelled by phalloidin to observe macrophage morphological changes. Moreover, phenotypic alteration of macrophages was measured using quantitative real-time PCR (qRT-PCR), flow cytometry, and immunofluorescence (IF) staining. Ultimately, recombinant human CCL19 and CCL21 were added into the medium of THP-1 derived macrophages to explore their effects on polarization in vitro.

RESULTS

In OSCC patients, the overexpression of CCR7 positively correlated with lymph node metastasis and M2 macrophage infiltration. Macrophage not only exhibited enhanced migration, invasion and adhesion abilities, but also appeared more spindle and branched in vitro when treated with CM from OSCC cells. However, these phenomena were abrogated with knockdown of CCR7. We also discovered that inhibition of CCR7 in OSCC cells suppressed TAMs polarization to an M2 phenotype. In addition, recombinant human CCL19 and CCL21 promoted macrophage M2-polarization in vitro.

CONCLUSION

CCR7 in OSCC cells promoted recruitment and M2-polarization of THP-1 derived macrophages in vitro by regulating production of CCL19 and CCL21.

Reprogramming Metabolism of Macrophages as a Target for Kidney Dysfunction Treatment in Autoimmune Diseases

Chronic kidney disease (CKD), as one of the main complications of many autoimmune diseases, is difficult to cure, which places a huge burden on patients' health and the economy and poses a great threat to human health. At present, the mainstream view is that autoimmune diseases are a series of diseases and complications caused by immune cell dysfunction leading to the attack of an organism's tissues by its immune cells. The kidney is the organ most seriously affected by autoimmune diseases as it has a very close relationship with immune cells. With the development of an in-depth understanding of cell metabolism in recent years, an increasing number of scientists have discovered the metabolic changes in immune cells in the process of disease development, and we have a clearer understanding of the characteristics of the metabolic changes in immune cells. This suggests that the regulation of immune cell metabolism provides a new direction for the treatment and prevention of kidney damage caused by autoimmune diseases. Macrophages are important immune cells and are a double-edged sword in the repair process of kidney injury. Although they can repair damaged kidney tissue, over-repair will also lead to the loss of renal structural reconstruction function. In this review, from the perspective of metabolism, the metabolic characteristics of macrophages in the process of renal injury induced by autoimmune diseases are described, and the metabolites that can regulate the function of macrophages are summarized. We believe that treating macrophage metabolism as a target can provide new ideas for the treatment of the renal injury caused by autoimmune diseases.

Resveratrol and ω-3 PUFAs Promote Human Macrophage Differentiation and Function

Monocytes differentiate into M1 and M2 macrophages, which are classically activated by microbial products such as LPS or IFN-γ and interleukins (e.g., the anti-inflammatory and T_h2 promoting IL-4), respectively. The contribution of nutrients or nutrient-based substances such as ω-3 polyunsaturated fatty acids (ω-3 PUFAs) and resveratrol (Res) on the differentiation and function of M1 and M2 macrophages was evaluated. THP-1 cells and peripheral blood mononuclear cells (PBMCs) were differentiated into M1 and M2 cells and activated with LPS/IFN-γ or IL-4/IL-13. Macrophage lineage specific surface determinants (e.g., CD11b, CD11c, CD14, CD206, CD209, CD274, HLA-DR, CCR7, CCR2) were analysed by cytofluorometry. Res and ω-3 PUFAs altered CD14, CD206, CD274 and HL-DR surface expression patterns in M1 and M2 macrophages differentiated from PBMC. LPS/IFN-γ or IL-14/IL-13 activated macrophages subpopulations, which secreted cytokines and chemokines as measured by multiplex ELISA. Res and ω-3 PUFA reduced IL-1β, IL-6, TNF-α, CXCL10/IP-10, CCL13/MCP-4 and CCL20/MIP-3α in LPS/IFN-γ activated human leukaemia THP-1 cells, which is indicative of a dampening effect on M1 macrophages. However, Res increased M1 prototypic cytokines such as IL-1β or IL-6 in macrophages derived from PBMCs and also modified the expression of IL-12p70. Collectively, Res and ω-3 PUFAs distinctly promoted the differentiation and function of M1 and M2 macrophages. We conclude that these substances strengthen the macrophage-mediated effects on the innate and adaptive immune response.

The influence of phytochemicals on cell heterogeneity in chronic inflammation-associated diseases: the prospects of single cell sequencing

Chronic inflammation-associated diseases include, but is not limited to cardiovascular disease, cancer, obesity, diabetes, etc. Cell heterogeneity is a prerequisite for understanding the physiological and pathological development of cell metabolism, and its response to external stimuli. Recently, dietary habits based on phytochemicals became increasingly recognized to play a pivotal role in chronic inflammation. Phytochemicals can relieve chronic inflammation by regulating inflammatory cell differentiation and immune cell response, but the influence of phytochemicals on cell heterogeneity from in vitro and ex vivo studies cannot simulate the complexity of cell differentiation in vivo due to the differences in cell lines and extracellular environment. Therefore, there is no consensus on the regulation mechanism of phytochemicals on chronic diseases based on cell heterogeneity. The purpose of this review is to summarize cell heterogeneity in common chronic inflammation-associated diseases and trace the effects of phytochemicals on cell differentiation in chronic diseases development. More importantly, by discussing the problems and challenges which hinder the study of cell heterogeneity in recent nutritional assessment experiments, we propose new prospects based on the drawbacks of existing research to optimize the research on the regulation mechanism of phytochemicals on chronic diseases. The need to explore precise measurements of cell heterogeneity is a key pillar in understanding the influence of phytochemicals on certain diseases. In the future, deeper understanding of cell-to-cell variation and the impact of food components and their metabolites on cell function by single-cell genomics and epigenomics with the focus on individual differences will open new avenues for the next generation of health care.

Weathering the Storm: Harnessing the Resolution of Inflammation to Limit COVID-19 Pathogenesis

The resolution of inflammation is a temporally and spatially coordinated process that in its innate manifestations, primarily involves neutrophils and macrophages. The shutdown of infection or injury-induced acute inflammation requires termination of neutrophil accumulation within the affected sites, neutrophil demise, and clearance by phagocytes (efferocytosis), such as tissue-resident and monocyte-derived macrophages. This must be followed by macrophage reprogramming from the inflammatory to reparative and consequently resolution-promoting phenotypes and the production of resolution-promoting lipid and protein mediators that limit responses in various cell types and promote tissue repair and return to homeostatic architecture and function. Recent studies suggest that these events, and macrophage reprogramming to pro-resolving phenotypes in particular, are not only important in the acute setting, but might be paramount in limiting chronic inflammation, autoimmunity, and various uncontrolled cytokine-driven pathologies. The SARS-CoV-2 (COVID-19) pandemic has caused a worldwide health and economic crisis. Severe COVID-19 cases that lead to high morbidity are tightly associated with an exuberant cytokine storm that seems to trigger shock-like pathologies, leading to vascular and multiorgan failures. In other cases, the cytokine storm can lead to diffuse alveolar damage that results in acute respiratory distress syndrome (ARDS) and lung failure. Here, we address recent advances on effectors in the resolution of inflammation and discuss how pro-resolution mechanisms with particular emphasis on macrophage reprogramming, might be harnessed to limit the universal COVID-19 health threat.

Amelioration of Endotoxemia by a Synthetic Analog of Omega-3 Epoxyeicosanoids

Sepsis, a systemic inflammatory response to pathogenic factors, is a difficult to treat life-threatening condition associated with cytokine and eicosanoid storms and multi-organ damage. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic (EPA) and docosahexaenoic acid, are the precursors of potent anti-inflammatory lipid mediators, including 17,18-epoxyeicosatetraenoic acid (17,18-EEQ), the main metabolite of EPA generated by cytochrome P450 epoxygenases. Searching for novel therapeutic or preventative agents in sepsis, we tested a metabolically robust synthetic analog of 17,18-EEQ (EEQ-A) for its ability to reduce mortality, organ damage, and pro-inflammatory cytokine transcript level in a mouse model of lipopolysaccharide (LPS)-induced endotoxemia, which is closely related to sepsis. Overall survival significantly improved following preventative EEQ-A administration along with decreased transcript level of pro-inflammatory cytokines. On the other hand, the therapeutic protocol was effective in improving survival at 48 hours but insignificant at 72 hours. Histopathological analyses showed significant reductions in hemorrhagic and necrotic damage and infiltration in the liver. In vitro studies with THP-1 and U937 cells showed EEQ-A mediated repression of LPS-induced M1 polarization and enhancement of IL-4-induced M2 polarization of macrophages. Moreover, EEQ-A attenuated the LPS-induced decline of mitochondrial function in THP-1 cells, as indicated by increased basal respiration and ATP production as well as reduction of the metabolic shift to glycolysis. Taken together, these data demonstrate that EEQ-A has potent anti-inflammatory and immunomodulatory properties that may support therapeutic strategies for ameliorating the endotoxemia.

Multifunctional Role of Lipids in Modulating the Tumorigenic Properties of 4T1 Breast Cancer Cells

Tumor growth and progression are linked to an altered lipid metabolism in the tumor microenvironment (TME), including tumor cells and tumor-associated macrophages (TAMs). A growing number of lipid metabolism targeting drugs have shown efficacy in anti-tumor therapy. In addition, exogenously applied lipids and lipid analogues have demonstrated anti-tumor activities in several cancers, including breast cancer. In this study, we investigated the anti-tumor efficacies of the natural lipids palmitic acid (PA), sphingomyelin (SM), ceramide (Cer) and docosahexaenoic acid (DHA) on breast cancer cells. All tested lipids reduced the malignancy of breast cancer cells in vitro by impairing cell proliferation, migration and invasiveness. PA showed superior anti-tumor properties, as it additionally impaired cancer cell viability by inducing apoptosis, without affecting healthy cells. Co-culture experiments further demonstrated that Cer and PA reduced the immunosuppressive phenotype of M2 macrophages and the M2 macrophage-promoted the epithelial–mesenchymal transition (EMT) and migration of breast cancer cells. At the molecular level, this coincided with the up-regulation of E-cadherin. Our results highlight a powerful role for exogenously applied PA and Cer in reducing breast cancer tumorigenicity by simultaneously targeting cancer cells and M2 macrophages. Our findings support the notion that lipids represent alternative biocompatible therapeutic agents for breast cancer.

Autophagy and skin wound healing

Autophagy is a lysosome-dependent, self-renewal mechanism that can degrade and recycle cellular components in eukaryotic cells to maintain the stability of the intracellular environment and the cells ability to cope with unfavorable environments. Numerous studies suggest that autophagy participates in regulating various cellular functions and is closely associated with the onset and progression of various diseases. Wound healing is a complex, multistep biological process that involves multiple cell types. Refractory wounds, which include diabetic skin ulcers, can seriously endanger human health. Previous studies have confirmed that autophagy plays an essential role in various phases of wound healing. Specifically, in the inflammatory phase, autophagy has an anti-infection effect and it negatively regulates the inflammatory response, which prevents excessive inflammation from causing tissue damage. In the proliferative phase, local hypoxia in the wound can induce autophagy, which plays a role in anti-apoptosis and anti-oxidative stress and promotes cell survival. Autophagy of vascular endothelial cells promotes wound angiogenesis and that of keratinocytes promotes their differentiation, proliferation and migration, which is conducive to the completion of wound re-epithelialisation. In the remodeling phase, autophagy of fibroblasts affects the formation of hypertrophic scars. Additionally, a refractory diabetic wound may be associated with increased levels of autophagy, and the regulation of mesenchymal stem cell autophagy may improve its application to wound healing. Therefore, understanding the relationship between autophagy and skin wound healing and exploring the molecular mechanism of autophagy regulation may provide novel strategies for the clinical treatment of wound healing.

Multi-Omic Profiling of Macrophages Treated with Phospholipids Containing Omega-3 and Omega-6 Fatty Acids Reveals Complex Immunomodulatory Adaptations at Protein, Lipid and Metabolic Levels

In recent years, several studies have demonstrated that polyunsaturated fatty acids have strong immunomodulatory properties, altering several functions of macrophages. In the present work, we sought to provide a multi-omic approach combining the analysis of the lipidome, the proteome, and the metabolome of RAW 264.7 macrophages supplemented with phospholipids containing omega-3 (PC 18:0/22:6; ω3-PC) or omega-6 (PC 18:0/20:4; ω6-PC) fatty acids, alone and in the presence of lipopolysaccharide (LPS). Supplementation of macrophages with ω3 and ω6 phospholipids plus LPS produced a significant reprogramming of the proteome of macrophages and amplified the immune response; it also promoted the expression of anti-inflammatory proteins (e.g., pleckstrin). Supplementation with the ω3-PC and ω6-PC induced significant changes in the lipidome, with a marked increase in lipid species linked to the inflammatory response, attributed to several pro-inflammatory signalling pathways (e.g., LPCs) but also to the pro-resolving effect of inflammation (e.g., PIs). Finally, the metabolomic analysis demonstrated that supplementation with ω3-PC and ω6-PC induced the expression of several metabolites with a pronounced inflammatory and anti-inflammatory effect (e.g., succinate). Overall, our data show that supplementation of macrophages with ω3-PC and ω6-PC effectively modulates the lipidome, proteome, and metabolome of these immune cells, affecting several metabolic pathways involved in the immune response that are triggered by inflammation.

Mesenchymal stem cell-derived extracellular vesicles prevent glioma by blocking M2 polarization of macrophages through a miR-744-5p/TGFB1-dependent mechanism

AIM

Our current study is conducted with intention to explore the regulatory mechanism of mesenchymal stem cell (MSC)-derived extracellular vesicle (EV)-miR-744-5p in glioma.

METHODS

Expression patterns of TGFB1, TGFBR1, and miR-744-5p were determined. EVs were isolated from human MSCs, which were characterized. Then, macrophages were co-cultured with MSCs with ectopic miR-744-5p expression to explore its role in cell proliferation, invasion, and migration capabilities. A nude mouse model of glioma xenograft was developed to observe the tumorigenesis and metastasis ability of glioma in vivo.

RESULTS

TGFB1 and TGFBR1 were upregulated in glioma. TGFB1 promoted M2 polarization of macrophages through theMAPK signaling, thereby promoting the progression of glioma. MSC-EVs suppressed TGFB1 expression in macrophages and inhibited M2 polarization of macrophages. MSC-EVs-miR-744-5p/TGFB1/MAPK axis inhibited M2 polarization of macrophages and reduced the malignant phenotypes of glioma cells. In vivo experiments verified that MSC-EVs-miR-744-5p inhibited the polarization of macrophage M2 and prevented glioma progression.

CONCLUSION

Taken together, MSC-EVs-miR-744-5p may suppress the MAPK signaling activity by downregulating TGFB1, and then inhibit polarization of macrophages M2, thereby preventing the progression of glioma. Graphical Headlights 1. TGFB1 promotes the M2 polarization of macrophages via the MAPK signaling. 2. miR-744-5p carried by MSC-EVs targets and inhibits TGFB1. 3. MSC-EV-miR-744-5p inhibits M2 polarization of macrophages to prevent glioma progression. 4. miR-744-5p loaded by MSC-EVs may be a preventive strategy against glioma.

Nobiletin mitigates NAFLD via lipophagy and inflammation

Nonalcoholic fatty liver disease (NAFLD), an increasingly serious health issue in the world, was characterized as lipid metabolic disorder without a satisfactory treatment. Nobiletin (NOB), a citrus flavonoid, was considered...

Insight on Polyunsaturated Fatty Acids in Endometrial Receptivity

Endometrial receptivity plays a crucial role in fertilization as well as pregnancy outcome in patients faced with fertility challenges. The optimization of endometrial receptivity may help with normal implantation of the embryo, and endometrial receptivity may be affected by numerous factors. Recently, the role of lipids in pregnancy has been increasingly recognized. Fatty acids and their metabolites may be involved in all stages of pregnancy and play a role in supporting cell proliferation and development, participating in cell signaling and regulating cell function. Polyunsaturated fatty acids, in particular, are essential fatty acids for the human body that can affect the receptivity of the endometrium through in a variety of methods, such as producing prostaglandins, estrogen and progesterone, among others. Additionally, polyunsaturated fatty acids are also involved in immunity and the regulation of endometrial decidualization. Fatty acids are essential for fetal placental growth and development. The interrelationship of polyunsaturated fatty acids with these substances and how they may affect endometrial receptivity will be reviewed in this article.

Sirtuin 6 regulates macrophage polarization to alleviate sepsis-induced acute respiratory distress syndrome via dual mechanisms dependent on and independent of autophagy

BACKGROUND AIMS

Sepsis-induced acute respiratory distress syndrome (ARDS) can be mediated by an imbalance in macrophage polarization; however, the underlying mechanisms remain poorly understood. This study aimed to investigate the modulatory role of sirtuin 6 (SIRT6) in macrophage polarization during sepsis-induced ARDS.

METHODS

A mouse ARDS model was established using cecal ligation and puncture. Isolated alveolar macrophages (AMs) and lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMDMs) were adopted as in vitro models. Macrophage polarization was evaluated by measuring M1 and M2 macrophage percentages via flow cytometry and expression of specific markers. The expression of microtubule-associated light chain protein 3I/II and beclin-1 was detected for assessing macrophage autophagy. Binding between specificity protein 1 (SP1) and the target gene promoter was evaluated using a chromatin immunoprecipitation assay. RNA expression was analyzed by quantitative reverse transcription polymerase chain reaction and western blotting.

RESULTS

Treatment with the SIRT6 activator UBCS039 significantly alleviated lung injury in the mouse ARDS model and enhanced autophagy and M2 polarization in isolated AMs. M2 polarization and autophagy in LPS-challenged BMDMs were also effectively promoted by UBCS039 treatment or SIRT6 overexpression. An adenosine monophosphate-activated protein kinase inhibitor (Compound C) or autophagy inhibitor (3-methyladenine) partially abrogated M2 polarization mediated by SIRT6 overexpression upon LPS exposure. SIRT6 induced autophagy and M2 polarization of BMDMs partially via its deacetylase activity. SIRT6 inhibited mammalian target of rapamycin transcription by modulating SP1 to promote BMDM M2 polarization, which was independent of autophagy.

CONCLUSIONS

SIRT6 promotes M2 polarization of macrophages to alleviate sepsis-induced ARDS in an autophagy-dependent and -independent manner.

PPAR-gamma agonists: Potential modulators of autophagy in obesity

Autophagy pathways are involved in the pathogenesis of some obesity related health problems. As obesity is a nutrient sufficiency condition, autophagy process can be altered in obesity through AMP activated protein kinase (AMPK) inhibition. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) as the main modulator of adipogenesis process can be effective in the regulation of obesity related phenotypes. As well, it has been revealed that PPAR-gamma and its agonists can regulate autophagy in different normal or cancer cells. However, their effects on autophagy modulation in obesity have been investigated in the limited number of studies. In the current comprehensive mechanistic review, we aimed to investigate the possible mechanisms of action of PPAR-gamma on the process of autophagy in obesity through narrating the effects of PPAR-gamma on autophagy in the non-obesity conditions. Moreover, mode of action of PPAR-gamma agonists on autophagy related implications comprehensively reviewed in the various studies. Understanding the different effects of PPAR-gamma agonists on autophagy in obesity can help to develop a new approach to management of obesity.

Fish Gelatin-Based Absorbable Dural Sealant with Anti-inflammatory Properties

Cerebrospinal fluid (CSF) leakage from the dura mater during craniotomy is a common complication, which is associated with infection, meningitis, pneumocephalus, and delayed wound healing. In the present study, we developed an absorbable fish gelatin-based anti-inflammatory sealant for dura mater sealing to prevent CSF leakage. Gelatin derived from Alaska pollock (ApGltn) was modified with α-linolenic acid (ALA), an omega-3 fatty acid that exhibits anti-inflammatory properties, and cross-linked with a poly(ethylene glycol)-based cross-linker to develop ALA-ApGltn sealant (ALA-Seal). ALA-Seal demonstrated a higher storage modulus and tangent delta (tan δ) compared with those of the original ApGltn sealant (Org-Seal). The swelling ratio of ALA-Seal was markedly lower than that of DuraSeal, a commercially available dural sealant. Ex vivo burst strength measurements using porcine dura mater indicated that there was no significant difference between DuraSeal and ALA-Seal, despite ALA-Seal having an order of magnitude lower storage modulus. The anti-inflammatory properties of ALA-Seal, evaluated using brain microglial cells, were considerably higher than those of DuraSeal and Org-Seal, with a minimal adverse effect on cell viability. Therefore, compared to DuraSeal, ALA-Seal is a potential dural sealant with a lower swelling ratio, similar burst strength, and higher anti-inflammatory properties, which may prevent CSF leakage.

Bioactive Lipids and Their Derivatives in Biomedical Applications

Lipids, which along with carbohydrates and proteins are among the most important nutrients for the living organism, have a variety of biological functions that can be applied widely in biomedicine. A fatty acid, the most fundamental biological lipid, may be classified by length of its aliphatic chain, and the short-, medium-, and long-chain fatty acids and each have distinct biological activities with therapeutic relevance. For example, short-chain fatty acids have immune regulatory activities and could be useful against autoimmune disease; medium-chain fatty acids generate ketogenic metabolites and may be used to control seizure; and some metabolites oxidized from long-chain fatty acids could be used to treat metabolic disorders. Glycerolipids play important roles in pathological environments, such as those of cancers or metabolic disorders, and thus are regarded as a potential therapeutic target. Phospholipids represent the main building unit of the plasma membrane of cells, and play key roles in cellular signaling. Due to their physical properties, glycerophospholipids are frequently used as pharmaceutical ingredients, in addition to being potential novel drug targets for treating disease. Sphingolipids, which comprise another component of the plasma membrane, have their own distinct biological functions and have been investigated in nanotechnological applications such as drug delivery systems. Saccharolipids, which are derived from bacteria, have endotoxin effects that stimulate the immune system. Chemically modified saccharolipids might be useful for cancer immunotherapy or as vaccine adjuvants. This review will address the important biological function of several key lipids and offer critical insights into their potential therapeutic applications.

Dietary Fatty Acids at the Crossroad between Obesity and Colorectal Cancer: Fine Regulators of Adipose Tissue Homeostasis and Immune Response

Colorectal cancer (CRC) is among the major threatening diseases worldwide, being the third most common cancer, and a leading cause of death, with a global incidence expected to increase in the coming years. Enhanced adiposity, particularly visceral fat, is a major risk factor for the development of several tumours, including CRC, and represents an important indicator of incidence, survival, prognosis, recurrence rates, and response to therapy. The obesity-associated low-grade chronic inflammation is thought to be a key determinant in CRC development, with the adipocytes and the adipose tissue (AT) playing a significant role in the integration of diet-related endocrine, metabolic, and inflammatory signals. Furthermore, AT infiltrating immune cells contribute to local and systemic inflammation by affecting immune and cancer cell functions through the release of soluble mediators. Among the factors introduced with diet and enriched in AT, fatty acids (FA) represent major players in inflammation and are able to deeply regulate AT homeostasis and immune cell function through gene expression regulation and by modulating the activity of several transcription factors (TF). This review summarizes human studies on the effects of dietary FA on AT homeostasis and immune cell functions, highlighting the molecular pathways and TF involved. The relevance of FA balance in linking diet, AT inflammation, and CRC is also discussed. Original and review articles were searched in PubMed without temporal limitation up to March 2021, by using fatty acid as a keyword in combination with diet, obesity, colorectal cancer, inflammation, adipose tissue, immune cells, and transcription factors.

Long Chain Fatty Acids as Modulators of Immune Cells Function: Contribution of FFA1 and FFA4 Receptors

Long-chain fatty acids are molecules that act as metabolic intermediates and constituents of membranes; however, their novel role as signaling molecules in immune function has also been demonstrated. The presence of free fatty acid (FFA) receptors on immune cells has contributed to the understanding of this new role of long-chain fatty acids (LCFAs) in immune function, showing their role as anti-inflammatory or pro-inflammatory molecules and elucidating their intracellular mechanisms. The FFA1 and FFA4 receptors, also known as GPR40 and GPR120, respectively, have been described in macrophages and neutrophils, two key cells mediating innate immune response. Ligands of the FFA1 and FFA4 receptors induce the release of a myriad of cytokines through well-defined intracellular signaling pathways. In this review, we discuss the cellular responses and intracellular mechanisms activated by LCFAs, such as oleic acid, linoleic acid, palmitic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), in T-cells, macrophages, and neutrophils, as well as the role of the FFA1 and FFA4 receptors in immune cells.

IL-24 deficiency protects mice against bleomycin-induced pulmonary fibrosis by repressing IL-4-induced M2 program in macrophages

Idiopathic pulmonary fibrosis (IPF) is the most common type of idiopathic interstitial pneumonia and has one of the poorest prognosis. However, the molecular mechanisms underlying IPF progression remain largely unknown. In this study, we determined that IL-24, an IL-20 subfamily cytokine member, was increased both in the serum of IPF patients and the bronchoalveolar lavage fluid (BALF) of mice following bleomycin (BLM)-induced pulmonary fibrosis. As a result, IL-24 deficiency protected mice from BLM-induced lung injury and fibrosis. Specifically, loss of IL-24 significantly attenuated transforming growth factor β1 (TGF-β1) production and reduced M2 macrophage infiltration in the lung of BLM-induced mice. Mechanistically, IL-24 alone did not show a perceptible impact on the induction of M2 macrophages, but it synergized with IL-4 to promote M2 program in macrophages. IL-24 suppressed IL-4-induced expression of suppressor of cytokine signaling 1 (SOCS1) and SOCS3, through which it enhanced signal transducer and activator of transcription 6/peroxisome proliferator-activated receptor gamma (STAT6/PPARγ) signaling, thereby promoting IL-4-induced production of M2 macrophages. Collectively, our data support that IL-24 synergizes with IL-4 to promote macrophage M2 program contributing to the development of pulmonary fibrosis.

Therapeutic treatment of dietary docosahexaenoic acid for particle-induced pulmonary inflammation in Balb/c mice

OBJECTIVE AND DESIGN

The omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) has been reported to suppress inflammation. Pulmonary inflammation can be directly linked to exposure of various occupational and man-made particles leading to pulmonary diseases. Therapeutic treatments are lacking for particle-induced pulmonary inflammation. These studies evaluated DHA as a therapeutic treatment for semi-acute and chronic particle-induced pulmonary inflammation.

METHODS

Balb/c mice were oropharyngeal instilled with hydrophobic multi-walled carbon nanotube (MWCNT) or hydrophilic crystalline silica (SiO2) either as one instillation (semi-acute) or once a week for 4 weeks (chronic). One week later, the mice were placed on either a control or 1% DHA-containing diet for 3 weeks (semi-acute) or 12 weeks (chronic). Mice were assessed for inflammatory signaling within the lung lavage fluid, impact on phagolysosomal membrane permeability, shifts of macrophage phenotype gene expression (M1, M2a, M2b, and M2c), and pulmonary histopathology.

RESULTS

DHA increased pulmonary inflammatory markers and lung pathology when mice were exposed to SiO2. There were trending decreases of inflammatory markers for MWCNT-exposed mice with DHA treatment, however, mostly not statistically significant.

CONCLUSION

The anti-inflammatory benefits of DHA treatment depend upon the type of inflammatory particle, magnitude of inflammation, and duration of treatment.