Resolution of Inflammation: What Controls Its Onset?

Sub-acute toxicity, antinociceptive and anti-inflammatory effects of Mucuna pruriens L. leaves in experimental rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Mucuna pruriens L is a wild and cultivated leguminous plant which have been used as an aphrodisiac, diuretic, nerve tonic, and antiarthritic agent.

AIM

To evaluate the toxicity, antinociceptive, and anti-inflammatory activities of M. pruriens (EEMP) ethanol extract in experimental models.

METHODS

M. pruriens dried leaves were extracted using aqueous ethanol (30:70). Tests for acute and subacute toxicity were conducted on rats and mice. Mice were used in hotplate, acetic acid, and formalin models to test the antinociceptive activity of EEMP. The anti-inflammatory properties of EEMP (25, 100, and 400 mg/kg) were assessed egg albumin, carrageenan, and formalin-induced oedema models. The study examined the anti-inflammatory mechanism of EEMP (25-400 mg/kg) in rats with an air pouch caused by carrageenan. Air pouch exudates were tested for total leucocytes and differential cell counts, TNF-α, IL-6, myeloperoxidase activity, malondialdehyde, nitrites, and reduced glutathione (GSH).

RESULTS

The acute oral toxic dose of EEMP is greater than 2000 mg/kg. There were no significant behavioral, hematological or biochemical alterations seen after 14-days repeated administration of EEMP (200, 400 and 800 mg/kg) in mice. The EEMP demonstrated significant antinociceptive activity in hotplate, acetic acid and formalin-induced nociception in mice. The EEMP significantly and dose dependently reduced paw oedema at 2, 4 and 96 h in the egg-albumin, carrageenan- and formalin-induced paw oedema, respectively. Exudates volume, inflammatory cell counts, TNF-α, IL-6, myeloperoxidase, malondialdehyde and nitrites were significantly reduced, while GSH increased in carrageenan-air pouch of EEMP-treated rats.

CONCLUSION

Mucuna pruriens leaves ethanol extract demonstrated good safety profile as well as antinociceptive and anti-inflammatory activity through mechanisms related to inhibition of oxidative stress and pro-inflammatory cytokines as well as lysosomal membrane stability.

Sulforaphane-mediated immune regulation through inhibition of NF-kB and MAPK signaling pathways in human dendritic cells

Inflammation and immune responses are intricately intertwined processes crucial for maintaining homeostasis and combating against pathogens. These processes involve complex signaling pathways, notably the Nuclear Factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) pathways, which play crucial roles. Sulforaphane (SFN), a nutraceutic, has emerged as a potential regulator of NF-κB and MAPK signaling pathways, exhibiting anti-inflammatory properties. However, limited knowledge exists regarding SFN's effects on immune cell modulation. This study aimed to assess the immunomodulatory capacity of SFN pretreatment in human dendritic cells (DCs), followed by exposure to a chronic inflammatory environment induced by lipopolysaccharide. SFN pretreatment was found to inhibit the NF-κB and MAPK signaling pathways, resulting in phenotypic changes in DCs characterized by a slight reduction in the expression of surface markers, as well as a decrease of TNF-α/IL-10 ratio. Additionally, SFN pretreatment enhanced the proliferation of Treg-cells and promoted the production of IL-10 by B-cells before exposure to the chronic inflammatory environment. Furthermore, these changes in DCs were found to be influenced by the inhibition of NF-κB and MAPK pathways (specifically p38 MAPK and JNK), suggesting that these pathways may play a role in the regulation of the differentiation of adaptive immune responses (proliferation of T- and IL-10-producing regulatory-cells), prior to SFN pretreatment. Our findings suggest that SFN pretreatment may induce a regulatory response by inhibiting NF-κB and MAPK signaling pathways in an inflammatory environment. SFN could be considered a promising strategy for utilizing functional foods to protect against inflammation and develop immunoregulatory interventions.

An LGR6 frameshift variant abrogates receptor expression on select leukocyte subsets and is associated with viral infections

ABSTRACT

The leucine-rich repeat-containing G-protein-coupled receptor 6 (LGR6) was recently identified as the cognate receptor for the proresolving mediator maresin 1 (MaR1). To address the biological role of LGR6 in humans, we investigated the functional impact of a genetic variant in the gene encoding for LGR6, which is predicted to lead to a frameshift mutation in one of the receptor isoforms, on both receptor expression and immune cell responses. In neutrophils, monocytes, and natural killer (NK) cells from volunteers homozygous for this variant, we found a significant downregulation in the expression of LGR6 when compared with controls without the variant; whereas the LGR6 expression was essentially similar in monocyte-derived macrophages and CD8+ T cells. Functionally, loss of LGR6 expression was linked with a decreased ability of neutrophils and monocytes to phagocytose bacteria. We observed an increase in neutrophil chemotaxis and leukotriene B4 production and increased expression of activation markers, including markers for platelet-leukocyte phagocyte heterotypic aggregates, such as CD41, in neutrophils and monocytes from the variant group. Using data from the UK Biobank, we found that at a population level the rs4266947 variant, which is in high linkage disequilibrium with rs74355478, was associated with a higher incidence of viral infections. Intriguingly, neutrophils, NK cells, and CD8+ T cells from volunteers with the LGR6 variant displayed altered viral responses when stimulated with Toll-like receptor 3 (TLR3), TLR7/TLR8, and TLR9 agonists. Together, these findings shed new light on the cell type-specific regulation of LGR6 expression and the role of this receptor in directing host immune responses.

Engineered Mesenchymal Stromal Cell Exosomes-Loaded Microneedles Improve Corneal Healing after Chemical Injury

Corneal alkali burns represent a prevalent ophthalmic emergency with the potential to induce blindness. The main contributing mechanisms include excessive inflammation and delayed wound healing. Existing clinical therapies have limitations, promoting the exploration of alternative methods that offer improved efficacy and reduced side effects. Adipose-derived stem cell-exosome (ADSC-Exo) has the potential to sustain immune homeostasis and facilitate tissue regeneration. Nevertheless, natural ADSC-Exo lacks disease specificity and exhibits limited bioavailability on the ocular surface. In this study, we conjugated antitumor necrosis factor-α antibodies (aT) to the surface of ADSC-Exo using matrix metalloproteinase-cleavable peptide chains to create engineered aT-Exo with synergistic effects. In both in vivo and in vitro assessments, aT-Exo demonstrated superior efficacy in mitigating corneal injuries compared to aT alone, unmodified exosomes, or aT simply mixed with exosomes. The cleavable conjugation of aT-Exo notably enhanced wound healing and alleviated inflammation more effectively. Simultaneously, we developed poly(vinyl alcohol) microneedles (MNs) for precise and sustained exosome delivery. The in vivo results showcased the superior therapeutic efficiency of MNs compared with conventional topical administration and subconjunctival injection. Therefore, the bioactive nanodrugs-loaded MNs treatment presents a promising strategy for addressing ocular surface diseases.

Anadenanthera colubrina regulated LPS-induced inflammation by suppressing NF-κB and p38-MAPK signaling pathways

We aimed to determine the chemical profile and unveil Anadenanthera colubrina (Vell.) Brenan standardized extract effects on inflammatory cytokines expression and key proteins from immunoregulating signaling pathways on LPS-induced THP-1 monocyte. Using the RT-PCR and Luminex Assays, we planned to show the gene expression and the levels of IL-8, IL-1β, and IL-10 inflammatory cytokines. Key proteins of NF-κB and MAPK transduction signaling pathways (NF-κB, p-38, p-NF-κB, and p-p38) were detected by Simple Western. Using HPLC-ESI-MSn (High-Performance Liquid-Chromatography) and HPLC-HRESIMS, we showed the profile of the extract that includes an opus of flavonoids, including the catechins, quercetin, kaempferol, and the proanthocyanidins. Cell viability was unaffected up to 250 µg/mL of the extract (LD50 = 978.7 µg/mL). Thereafter, the extract's impact on the cytokine became clear. Upon LPS stimuli, in the presence of the extract, gene expression of IL-1β and IL-10 were downregulated and the cytokines expression of IL-1β and IL-10 were down an upregulated respectively. The extract is involved in TLR-4-related NF-κB/MAPK pathways; it ignited phosphorylation of p38 and NF-κB, orchestrating a reduced signal intensity. Therefore, Anadenanthera colubrina's showed low cytotoxicity and profound influence as a protector against the inflammation, modulating IL-1β and IL-10 inflammatory cytokines gene expression and secretion by regulating intracellular NF-κB and p38-MAPK signaling pathways.

From inflammation to bone formation: the intricate role of neutrophils in skeletal muscle injury and traumatic heterotopic ossification

Neutrophils are emerging as an important player in skeletal muscle injury and repair. Neutrophils accumulate in injured tissue, thus releasing inflammatory factors, proteases and neutrophil extracellular traps (NETs) to clear muscle debris and pathogens when skeletal muscle is damaged. During the process of muscle repair, neutrophils can promote self-renewal and angiogenesis in satellite cells. When neutrophils are abnormally overactivated, neutrophils cause collagen deposition, functional impairment of satellite cells, and damage to the skeletal muscle vascular endothelium. Heterotopic ossification (HO) refers to abnormal bone formation in soft tissue. Skeletal muscle injury is one of the main causes of traumatic HO (tHO). Neutrophils play a pivotal role in activating BMPs and TGF-β signals, thus promoting the differentiation of mesenchymal stem cells and progenitor cells into osteoblasts or osteoclasts to facilitate HO. Furthermore, NETs are specifically localized at the site of HO, thereby accelerating the formation of HO. Additionally, the overactivation of neutrophils contributes to the disruption of immune homeostasis to trigger HO. An understanding of the diverse roles of neutrophils will not only provide more information on the pathogenesis of skeletal muscle injury for repair and HO but also provides a foundation for the development of more efficacious treatment modalities for HO.

Comparative proteomic profiling of the ovine and human PBMC inflammatory response

Understanding the cellular and molecular mechanisms of inflammation requires robust animal models. Sheep are commonly used in immune-related studies, yet the validity of sheep as animal models for immune and inflammatory diseases remains to be established. This cross-species comparative study analyzed the in vitro inflammatory response of ovine (oPBMCs) and human PBMCs (hPBMCs) using mass spectrometry, profiling the proteome of the secretome and whole cell lysate. Of the entire cell lysate proteome (oPBMCs: 4217, hPBMCs: 4574 proteins) 47.8% and in the secretome proteome (oPBMCs: 1913, hPBMCs: 1375 proteins) 32.8% were orthologous between species, among them 32 orthologous CD antigens, indicating the presence of six immune cell subsets. Following inflammatory stimulation, 71 proteins in oPBMCs and 176 in hPBMCs showed differential abundance, with only 7 overlapping. Network and Gene Ontology analyses identified 16 shared inflammatory-related terms and 17 canonical pathways with similar activation/inhibition patterns in both species, demonstrating significant conservation in specific immune and inflammatory responses. However, ovine PMBCs also contained a unique WC1+γδ T-cell subset, not detected in hPBMCs. Furthermore, differences in the activation/inhibition trends of seven canonical pathways and the sets of DAPs between sheep and humans, emphasize the need to consider interspecies differences in translational studies and inflammation research.

Severe Allergy as a Chronic Inflammatory Condition From a Systems Biology Perspective

Persistent and unresolved inflammation is a common underlying factor observed in several and seemingly unrelated human diseases, including cardiovascular and neurodegenerative diseases. Particularly, in atopic conditions, acute inflammatory responses such as those triggered by insect venom, food or drug allergies possess also a life-threatening potential. However, respiratory allergies predominantly exhibit late immune responses associated with chronic inflammation, that can eventually progress into a severe phenotype displaying similar features as those observed in other chronic inflammatory diseases, as is the case of uncontrolled severe asthma. This review aims to explore the different facets and systems involved in chronic allergic inflammation, including processes such as tissue remodelling and immune cell dysregulation, as well as genetic, metabolic and microbiota alterations, which are common to other inflammatory conditions. Our goal here was to deepen on the understanding of an entangled disease as is chronic allergic inflammation and expose potential avenues for the development of better diagnostic and intervention strategies.

Mechanisms underlying aryl hydrocarbon receptor-driven divergent macrophage function

Macrophages play an essential role in the innate immune system by differentiating into functionally diverse subsets in order to fight infection, repair damaged tissues, and regulate inappropriate immune responses. This functional diversity stems from their ability to adapt and respond to signals in the environment, which is in part mediated through aryl hydrocarbon receptor (AHR)-signaling. AHR, an environmental sensor, can be activated by various ligands, ranging from environmental contaminants to microbially derived tryptophan metabolites. This review discusses what is currently known about how AHR-signaling influences macrophage differentiation, polarization, and function. By discussing studies that are both consistent and divergent, our goal is to highlight the need for future research on the mechanisms by which AHR acts as an immunological switch in macrophages. Ultimately, understanding the contexts in which AHR-signaling promotes and/or inhibits differentiation, proinflammatory functions, and immunoregulatory functions, will help uncover functional predictions of immunotoxicity following exposure to environmental chemicals as well as better design AHR-targeted immunotherapies.

Transcriptomic responses of peripheral blood leukocytes to cardiac surgery after acute inflammation, and three months recovery

Traumatic perioperative conditions may trigger early systemic responses, activate leukocytes and reprogram the immune system. We hypothesize that leukocyte activation may not revert to pre-surgical states, and that protracted activation may emerge with increased risks of comorbidities. We tested this concept by examining the transcriptomes of monocytes and T cells in a representative observational cohort of patients (n = 13) admitted for elective cardiac surgery. Transcriptomes in T cells and monocytes were compared from before surgery (t0), and monocytes were analyzed longitudinally after acute (t24hr), and convalescent (t3m) time points. Monocytes and T cells expressed distinct transcriptomes, reflected by statistically significant differential expression of 558 T cell related genes. Monocytes expressed genes related to protein degradation and presented atypical activation of surface markers and cytoplasmic functions over time. Additionally, monocytes exhibited limited transcriptomic heterogeneity prior to surgery, and long-term patterns of gene expression associated with atherosclerosis showed three temporally distinct signatures. These data establish that post-cardiac surgery transcriptomes of monocytes differ even at three months compared to baselines, which may reflect latent ('smoldering') inflammation and persistent progression of tissue degenerative processes that should inform clinical care.

STAT3 promotes cytoplasmic-nuclear translocation of RNA-binding protein HuR to inhibit IL-1β-induced IL-8 production

Signal transducer and activator of transcription 3 (STAT3) functions to regulate inflammation and immune response, but its mechanism is not fully understood. We report here that STAT3 inhibitors Stattic and Niclosamide up-regulated IL-1β-induced IL-8 production in C33A, CaSki, and Siha cervical cancer cells. As expected, IL-1β-induced IL-8 production was also up-regulated through the molecular inhibition of STAT3 by use of CRISPR/Cas9 technology. Unexpectedly, IL-1β induced IL-8 production via activating ERK and P38 signal pathways, but neither STAT3 inhibitors nor STAT3 knockout affected IL-1β-induced signal transduction, suggesting that STAT3 decreases IL-8 production not via inhibition of signal transduction. To our surprise, STAT3 inhibition increased the stabilization, and decreased the degradation of IL-8 mRNA, suggesting a post-transcriptional regulation of IL-1β-induced IL-8. Moreover, Dihydrotanshinone I, an inhibitor of RNA-binding protein HuR, down-regulated IL-1β-induced IL-8 dose-dependently. HuR inhibition by CRISPR/Cas9 also decreased IL-8 production induced by IL-1β. Mechanistically, co-immunoprecipitation results showed that STAT3 did not react with HuR directly, but STAT3 inhibition increased the protein levels of HuR in cytoplasm. And IL-6 activation of STAT3 induced HuR cytoplasmic-nuclear transport. Taken together, these results suggest that STAT3 contributes to HuR nuclear localization and inhibits Il-1β-induced IL-8 production through this non-transcriptional mechanism.

Collaboration between distinct SWI/SNF chromatin remodeling complexes directs enhancer selection and activation of macrophage inflammatory genes

Macrophages elicit immune responses to pathogens through induction of inflammatory genes. Here, we examined the role of three variants of the SWI/SNF nucleosome remodeling complex-cBAF, ncBAF, and PBAF-in the macrophage response to bacterial endotoxin (lipid A). All three SWI/SNF variants were prebound in macrophages and retargeted to genomic sites undergoing changes in chromatin accessibility following stimulation. Cooperative binding of all three variants associated with de novo chromatin opening and latent enhancer activation. Isolated binding of ncBAF and PBAF, in contrast, associated with activation and repression of active enhancers, respectively. Chemical and genetic perturbations of variant-specific subunits revealed pathway-specific regulation in the activation of lipid A response genes, corresponding to requirement for cBAF and ncBAF in inflammatory and interferon-stimulated gene (ISG) activation, respectively, consistent with differential engagement of SWI/SNF variants by signal-responsive transcription factors. Thus, functional diversity among SWI/SNF variants enables increased regulatory control of innate immune transcriptional programs, with potential for specific therapeutic targeting.

Inflammation and cancer: friend or foe?

Chronic inflammation plays a crucial role in the onset and progression of pathologies like neurodegenerative and cardiovascular diseases, diabetes, and cancer, since tumor development and chronic inflammation are linked, sharing common signaling pathways. At least 20% of breast and colorectal cancers are associated with chronic inflammation triggered by infections, irritants, or autoimmune diseases. Obesity, chronic inflammation, and cancer interconnection underscore the importance of population-based interventions in maintaining healthy body weight, to disrupt this axis. Given that the dietary inflammatory index is correlated with an increased risk of cancer, adopting an anti-inflammatory diet supplemented with nutraceuticals may be useful for cancer prevention. Natural products and their derivatives offer promising antitumor activity with favorable adverse effect profiles; however, the development of natural bioactive drugs is challenging due to their variability and complexity, requiring rigorous research processes. It has been shown that combining anti-inflammatory products, such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and statins, with plant-derived products demonstrate clinical utility as accessible adjuvants to traditional therapeutic approaches, with known safety profiles. Pharmacological approaches targeting multiple proteins involved in inflammation and cancer pathogenesis emerge as a particularly promising option. Given the systemic and multifactorial nature of inflammation, comprehensive strategies are essential for long term success in cancer therapy. To gain insights into carcinogenic phenomena and discover diagnostic or clinically relevant biomarkers, is pivotal to understand genetic variability, environmental exposure, dietary habits, and TME composition, to establish therapeutic approaches based on molecular and genetic analysis. Furthermore, the use of endocannabinoid, cannabinoid, and prostamide-type compounds as potential therapeutic targets or biomarkers requires further investigation. This review aims to elucidate the role of specific etiological agents and mediators contributing to persistent inflammatory reactions in tumor development. It explores potential therapeutic strategies for cancer treatment, emphasizing the urgent need for cost-effective approaches to address cancer-associated inflammation.

Targeting cyclooxygenase-2 for chemoprevention of inflammation-associated intestinal carcinogenesis: An update

Mounting evidence from preclinical and clinical studies suggests that persistent inflammation functions as a driving force in the journey to cancer. Cyclooxygenase-2 (COX-2) is a key enzyme involved in inflammatory signaling. While being transiently upregulated upon inflammatory stimuli, COX-2 has been found to be consistently overexpressed in human colorectal cancer and several other malignancies. The association between chronic inflammation and cancer has been revisited: cancer can arise when inflammation fails to resolve. Besides its proinflammatory functions, COX-2 also catalyzes the production of pro-resolving as well as anti-inflammatory metabolites from polyunsaturated fatty acids. This may account for the side effects caused by long term use of some COX-2 inhibitory drugs during the cancer chemopreventive trials. This review summarizes the latest findings highlighting the dual functions of COX-2 in the context of its implications in the development, maintenance, and progression of cancer.

STINGing away the pain: the role of interferon-stimulated genes

Pain and inflammation are biologically intertwined responses that warn the body of potential danger. In this issue of the JCI, Defaye, Bradaia, and colleagues identified a functional link between inflammation and pain, demonstrating that inflammation-induced activation of stimulator of IFN genes (STING) in dorsal root ganglia nociceptors reduced pain-like behaviors in a rodent model of inflammatory pain. Utilizing mice with a gain-of-function STING mutation, Defaye, Bradaia, and colleagues identified type I IFN regulation of voltage-gated potassium channels as the mechanism of this pain relief. Further investigation into mechanisms by which proinflammatory pathways can reduce pain may reveal druggable targets and insights into new approaches for treating persistent pain.

The Immunomodulatory effect of exosomes in diabetes: a novel and attractive therapeutic tool in diabetes therapy

Exosomes carry proteins, metabolites, nucleic acids and lipids from their parent cell of origin. They are derived from cells through exocytosis, are ingested by target cells, and can transfer biological signals between local or distant cells. Therefore, exosomes are often modified in reaction to pathological processes, including infection, cancer, cardiovascular diseases and in response to metabolic perturbations such as obesity and diabetes, all of which involve a significant inflammatory aspect. Here, we discuss how immune cell-derived exosomes origin from neutrophils, T lymphocytes, macrophages impact on the immune reprogramming of diabetes and the associated complications. Besides, exosomes derived from stem cells and their immunomodulatory properties and anti-inflammation effect in diabetes are also reviewed. Moreover, As an important addition to previous reviews, we describes promising directions involving engineered exosomes as well as current challenges of clinical applications in diabetic therapy. Further research on exosomes will explore their potential in translational medicine and provide new avenues for the development of effective clinical diagnostics and therapeutic strategies for immunoregulation of diabetes.

[Clinical and morphological features of lung injury long-term after SARS-CoV-2 recovery]

AIM

To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection.

MATERIALS AND METHODS

The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction.

RESULTS

The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process.

CONCLUSION

Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process.

Overnutrition and Lipotoxicity: Impaired Efferocytosis and Chronic Inflammation as Precursors to Multifaceted Disease Pathogenesis

Overnutrition, driven by the consumption of high-fat, high-sugar diets, has reached epidemic proportions and poses a significant global health challenge. Prolonged overnutrition leads to the deposition of excessive lipids in adipose and non-adipose tissues, a condition known as lipotoxicity. The intricate interplay between overnutrition-induced lipotoxicity and the immune system plays a pivotal role in the pathogenesis of various diseases. This review aims to elucidate the consequences of impaired efferocytosis, caused by lipotoxicity-poisoned macrophages, leading to chronic inflammation and the subsequent development of severe infectious diseases, autoimmunity, and cancer, as well as chronic pulmonary and cardiovascular diseases. Chronic overnutrition promotes adipose tissue expansion which induces cellular stress and inflammatory responses, contributing to insulin resistance, dyslipidemia, and metabolic syndrome. Moreover, sustained exposure to lipotoxicity impairs the efferocytic capacity of macrophages, compromising their ability to efficiently engulf and remove dead cells. The unresolved chronic inflammation perpetuates a pro-inflammatory microenvironment, exacerbating tissue damage and promoting the development of various diseases. The interaction between overnutrition, lipotoxicity, and impaired efferocytosis highlights a critical pathway through which chronic inflammation emerges, facilitating the development of severe infectious diseases, autoimmunity, cancer, and chronic pulmonary and cardiovascular diseases. Understanding these intricate connections sheds light on potential therapeutic avenues to mitigate the detrimental effects of overnutrition and lipotoxicity on immune function and tissue homeostasis, thereby paving the way for novel interventions aimed at reducing the burden of these multifaceted diseases on global health.

Resolution pharmacology and the treatment of infectious diseases

Inflammation is elicited by the host in response to microbes, and is believed to be essential for protection against infection. However, we have previously hypothesized that excessive or misplaced inflammation may be a major contributor to tissue dysfunction and death associated with viral and bacterial infections. The resolutive phase of inflammation is a necessary condition to achieve homeostasis after acute inflammation. It is possible that targeting inflammation resolution may be beneficial for the host during infection. In this review, we summarize the evidence demonstrating the expression, roles and effects of the best described pro-resolving molecules in the context of bacterial and viral infections. Pro-resolving molecules play a pivotal role in modulating a spectrum of pathways associated with tissue inflammation and damage during both viral and bacterial infections. These molecules offer a blend of anti-inflammatory, pro-resolving and sometimes anti-infective benefits, all the while circumventing the undesired and immune-suppressive unwanted effects associated with glucocorticoids. Whether these beneficial effects will translate into benefits to patients clearly deserve further investigation.

Regulation of immunomodulatory networks by Nrf2-activation in immune cells: Redox control and therapeutic potential in inflammatory diseases

Inflammatory diseases present a serious health challenge due to their widespread prevalence and the severe impact on patients' lives. In the quest to alleviate the burden of these diseases, nuclear factor erythroid 2-related factor 2 (Nrf2) has emerged as a pivotal player. As a transcription factor intimately involved in cellular defense against metabolic and oxidative stress, Nrf2's role in modulating the inflammatory responses of immune cells has garnered significant attention. Recent findings suggest that Nrf2's ability to alter the redox status of cells underlies its regulatory effects on immune responses. Our review delves into preclinical and clinical evidence that underscores the complex influence of Nrf2 activators on immune cell phenotypes, particularly in the inflammatory milieu. By offering a detailed analysis of Nrf2's role in different immune cell populations, we cast light on the potential of Nrf2 activators in shaping the immune response towards a more regulated state, mitigating the adverse effects of inflammation through modeling redox status of immune cells. Furthermore, we explore the innovative use of nanoencapsulation techniques that enhance the delivery and efficacy of Nrf2 activators, potentially advancing the treatment strategies for inflammatory ailments. We hope this review will stimulate the development and expansion of Nrf2-targeted treatments that could substantially improve outcomes for patients suffering from a broad range of inflammatory diseases.

Treatment with β-Adrenoceptor Agonist Isoproterenol Reduces Non-parenchymal Cell Responses in LPS/D-GalN-Induced Liver Injury

There is an increasing evidence indicating the involvement of the sympathetic nervous system (SNS) in liver disease development. To achieve an extensive comprehension of the obscure process by which the SNS alleviates inflammatory damage in non-parenchymal liver cells (NPCs) during acute liver failure (ALF), we employ isoproterenol (ISO), a beta-adrenoceptor agonist, to mimic SNS signaling. ISO was administered to C57BL/6J mice to establish an acute liver failure (ALF) model using LPS/D-GalN, which was defined as ISO + ALF. Non-parenchymal cells (NPCs) were isolated from liver tissues and digested for tandem mass tag (TMT) labeled proteomics to identify differentially expressed proteins (DEPs). The administration of ISO resulted in a decreased serum levels of pro-inflammatory cytokines, e.g., TNF-α, IL-1β, and IL-6 in ALF mice, which alleviated liver damage. By using TMT analysis, it was possible to identify 1587 differentially expressed proteins (DEPs) in isolated NPCs. Notably, over 60% of the DEPs in the ISO + ALF vs. ALF comparison were shared in the Con vs. ALF comparison. According to enrichment analysis, the DEPs influenced by ISO in ALF mice were linked to biological functions of heme and fatty acid metabolism, interferon gamma response, TNFA signaling pathway, and mitochondrial oxidation function. Protein-protein interaction network analysis indicated Mapk14 and Caspase3 may serve as potentially valuable indicators of ISO intervention. In addition, the markers on activated macrophages, such as Mapk14, Casp1, Casp8, and Mrc1, were identified downregulated after ISO initiation. ISO treatment increased the abundance of anti-inflammatory markers in mouse macrophages, as evidenced by the immunohistochemistry (IHC) slides showing an increase in Arg + staining and a reduction in iNOS + staining. Furthermore, pretreatment with ISO also resulted in a reduction of LPS-stimulated inflammation signaling markers, Mapk14 and NF-κB, in human THP-1 cells. Prior treatment with ISO may have the potential to modify the biological functions of NPCs and could serve as an innovative pharmacotherapy for delaying the pathogenesis and progression of ALF.

Innate Immune Training Initiates Efferocytosis to Protect against Lung Injury

Innate immune training involves myelopoiesis, dynamic gene modulation, and functional reprogramming of myeloid cells in response to secondary heterologous challenges. The present study evaluates whether systemic innate immune training can protect tissues from local injury. Systemic pretreatment of mice with β-glucan, a trained immunity agonist, reduces the mortality rate of mice with bleomycin-induced lung injury and fibrosis, as well as decreasing collagen deposition in the lungs. β-Glucan pretreatment induces neutrophil accumulation in the lungs and enhances efferocytosis. Training of mice with β-glucan results in histone modification in both alveolar macrophages (AMs) and neighboring lung epithelial cells. Training also increases the production of RvD1 and soluble mediators by AMs and efferocytes. Efferocytosis increases trained immunity in AMs by stimulating RvD1 release, thus inducing SIRT1 expression in neighboring lung epithelial cells. Elevated epithelial SIRT1 expression is associated with decreased epithelial cell apoptosis after lung injury, attenuating tissue damage. Further, neutrophil depletion dampens the effects of β-glucan on macrophage accumulation, epigenetic modification in lung macrophages, epithelial SIRT1 expression, and injury-mediated fibrosis in the lung. These findings provide mechanistic insights into innate immune training and clues to the potential ability of centrally trained immunity to protect peripheral organs against injury-mediated disorders.

The immunomodulatory effect of oral NaHCO3 is mediated by the splenic nerve: multivariate impact revealed by artificial neural networks

Stimulation of the inflammatory reflex (IR) is a promising strategy for treating systemic inflammatory disorders. Recent studies suggest oral sodium bicarbonate (NaHCO3) as a potential activator of the IR, offering a safe and cost-effective treatment approach. However, the mechanisms underlying NaHCO3-induced anti-inflammatory effects remain unclear. We investigated whether oral NaHCO3's immunomodulatory effects are mediated by the splenic nerve. Female rats received NaHCO3 or water (H2O) for four days, and splenic immune markers were assessed using flow cytometry. NaHCO3 led to a significant increase (p < 0.05, and/or partial eta squared > 0.06) in anti-inflammatory markers, including CD11bc + CD206 + (M2-like) macrophages, CD3 + CD4 + FoxP3 + cells (Tregs), and Tregs/M1-like ratio. Conversely, proinflammatory markers, such as CD11bc + CD38 + TNFα + (M1-like) macrophages, M1-like/M2-like ratio, and SSChigh/SSClow ratio of FSChighCD11bc + cells, decreased in the spleen following NaHCO3 administration. These effects were abolished in spleen-denervated rats, suggesting the necessity of the splenic nerve in mediating NaHCO3-induced immunomodulation. Artificial neural networks accurately classified NaHCO3 and H2O treatment in sham rats but failed in spleen-denervated rats, highlighting the splenic nerve's critical role. Additionally, spleen denervation independently influenced Tregs, M2-like macrophages, Tregs/M1-like ratio, and CD11bc + CD38 + cells, indicating distinct effects from both surgery and treatment. Principal component analysis (PCA) further supported the separate effects. Our findings suggest that the splenic nerve transmits oral NaHCO3-induced immunomodulatory changes to the spleen, emphasizing NaHCO3's potential as an IR activator with therapeutic implications for a wide spectrum of systemic inflammatory conditions.

The impact of novel inflammation-preserving treatment towards lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical outcomes study

PURPOSE

We performed a prospective one-year multi-imaging study to assess the clinical outcomes and rate of disc resorption in acute lumbar disc herniation (LDH) patients undergoing inflammation-preserving treatment (i.e. no NSAIDS, steroids).

METHODS

All patients received gabapentin to relieve leg pain, 12 sessions of acupuncture. Repeat MRI was performed, every 3 months, after 12 sessions of treatment continued for those without 40% reduction in herniated disc sagittal area. Disc herniations sizes were measured on sagittal T2W MRI sequences, pre-treatment and at post-treatment intervals. Patients were stratified to fast, medium, slow, and prolonged recovery groups in relation to symptom resolution and disc resorption.

RESULTS

Ninety patients (51% females; mean age: 48.6 years) were assessed. Mean size of disc herniation was 119.54 ± 54.34 mm2, and the mean VAS-Leg score was 6.12 ± 1.13 at initial presentation. A total of 19 patients (21.1%) improved at the time of the repeat MRI (i.e. within first 3 months post-treatment). 100% of all patient had LDH resorption within one year (mean: 4.4. months). There was no significant difference at baseline LDH between fast, medium, slow, and prolonged resorption groups. Initial LDH size was weakly associated with degree of leg pain at baseline and initial gabapentin levels. Surgery was avoided in all cases.

CONCLUSION

This is the first study to note inflammation-preserving treatment, without conventional anti-inflammatory and steroid medications, as safe and effective for patients with an acute LDH. Rate of disc resorption (100%) was higher than comparative recent meta-analysis findings (66.7%) and no patient underwent surgery.

Portable and Air Conditioner-Based Bio-Protection Devices to Prevent Airborne Infections in Acute and Long-Term Healthcare Facilities, Public Gathering Places, Public Transportation, and Similar Entities

The nature in which the coronavirus disease 2019 (COVID-19) pandemic started and spread all over the world has surprised and shocked experts and the general population alike. This has brought out a worldwide desire and serious efforts to prevent, or at least reduce, the severity of another airborne viral infection and protect individuals gathering for various reasons. Toward this main purpose, a novel method to disinfect the air, using graded, predictable, safe, and reliable dosage of ultraviolet C (UVC), with specially designed devices, is described here. Individuals exclusively breathing this disinfected air can prevent infection, thus destroying the airborne virus or any other pathogens outside the human body to prevent acute and chronic damage to the organs and provide a sense of security to congregate, use public transport, and be protected in acute and long-term healthcare facilities. The study involved designing and testing a unit with one UVC chamber and another unit with six UVC chambers both enclosed in UVC-opaque housings that could be used to destroy airborne pathogens. Wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was used as a representative pathogen. The virus was fed into these units and in both units, the virus was destroyed to undetectable levels. Such disinfected air can be made available for individuals to breathe at an individual and a community level. The two units that were studied were able to destroy the SARS-CoV-2 virus completely in UVC-opaque housings, making them safe for human use. By employing the air to bring the virus to the UVC, the problem of the virus getting protected behind structures was avoided. The individuals get to breathe totally disinfected air through a mask or a ventilator. To protect individuals who are unable or unwilling to use these units meant for individual use, the same principle can be expanded for use with air conditioners to provide community protection. It is envisaged that this method can prevent airborne infections from turning into pandemics and is a clear example of advocating prevention, rather than treatment. These units are expandable and the UVC dosage to the pathogen can be adjusted and predictable, thereby making it a standard technique to study the dosage needed to inactivate different pathogens.

Dynamic Boolean modeling of molecular and cellular interactions in psoriasis predicts drug target candidates

Psoriasis arises from complex interactions between keratinocytes and immune cells, leading to uncontrolled inflammation, immune hyperactivation, and a perturbed keratinocyte life cycle. Despite the availability of drugs for psoriasis management, the disease remains incurable. Treatment response variability calls for new tools and approaches to comprehend the mechanisms underlying disease development. We present a Boolean multiscale population model that captures the dynamics of cell-specific phenotypes in psoriasis, integrating discrete logical formalism and population dynamics simulations. Through simulations and network analysis, the model predictions suggest that targeting neutrophil activation in conjunction with inhibition of either prostaglandin E2 (PGE2) or STAT3 shows promise comparable to interleukin-17 (IL-17) inhibition, one of the most effective treatment options for moderate and severe cases. Our findings underscore the significance of considering complex intercellular interactions and intracellular signaling in psoriasis and highlight the importance of computational approaches in unraveling complex biological systems for drug target identification.

The interplay between obesity, immunosenescence, and insulin resistance

Obesity, which is the accumulation of fat in adipose tissue, has adverse impacts on human health. Obesity-related metabolic dysregulation has similarities to the metabolic alterations observed in aging. It has been shown that the adipocytes of obese individuals undergo cellular aging, known as senescence. Senescence can be transmitted to other normal cells through a series of chemical factors referred to as the senescence-associated secretory phenotype (SASP). Most of these factors are pro-inflammatory compounds. The immune system removes these senescent T-cells, but immunosenescence, which is the senescence of immune cells, disrupts the clearance of senescent T-cells. Immunosenescence occurs as a result of aging or indirectly through transmission from senescent tissues. The significant occurrence of senescence in obesity is expected to cause immunosenescence and impairs the immune response to resolve inflammation. The sustained and chronic inflammation disrupts insulin's metabolic actions in metabolic tissues. Therefore, this review focuses on the role of senescent adipocyte cells in obesity-associated immunosenescence and subsequent metabolic dysregulation. Moreover, the article suggests novel therapeutic approaches to improve metabolic syndrome by targeting senescent T-cells or using senotherapeutics.

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.

Longitudinal analysis of post-acute chikungunya-associated arthralgia in children and adults: A prospective cohort study in Managua, Nicaragua (2014-2018)

Chikungunya can result in debilitating arthralgia, often presenting as acute, self-limited pain, but occasionally manifesting chronically. Little is known about differences in chikungunya-associated arthralgia comparing children to adults over time. To characterize long-term chikungunya-associated arthralgia, we recruited 770 patients (105 0-4 years old [y/o], 200 5-9 y/o, 307 10-15 y/o, and 158 16+ y/o) with symptomatic chikungunya virus infections in Managua, Nicaragua, during two consecutive chikungunya epidemics (2014-2015). Participants were assessed at ~15 days and 1, 3, 6, 12, and 18 months post-fever onset. Following clinical guidelines, we defined participants by their last reported instance of arthralgia as acute (≤10 days post-fever onset), interim (>10 and <90 days), or chronic (≥90 days) cases. We observed a high prevalence of arthralgia (80-95%) across all ages over the study period. Overall, the odds of acute arthralgia increased in an age-dependent manner, with the lowest odds of arthralgia in the 0-4 y/o group (odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.14-0.51) and the highest odds of arthralgia in the 16+ y/o participants (OR: 4.91, 95% CI: 1.42-30.95) relative to 10-15 y/o participants. Females had higher odds of acute arthralgia than males (OR: 1.63, 95% CI: 1.01-2.65) across all ages. We found that 23-36% of pediatric and 53% of adult participants reported an instance of post-acute arthralgia. Children exhibited the highest prevalence of post-acute polyarthralgia in their legs, followed by the hands and torso - a pattern not seen among adult participants. Further, we observed pediatric chikungunya presenting in two distinct phases: the acute phase and the subsequent interim/chronic phases. Thus, differences in the presentation of arthralgia were observed across age, sex, and disease phase in this longitudinal chikungunya cohort. Our results elucidate the long-term burden of chikungunya-associated arthralgia among pediatric and adult populations.

Inhibition of pro-inflammatory cytokines by selected southern African medicinal plants in LPS-stimulated RAW 264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Bark is frequently used in southern African traditional medicine to treat inflammation, yet it remains to be rigorously examined for its immunological and anti-inflammatory activity.

AIM OF THE STUDY

Barks obtained from ten important and popular southern Africa plants were evaluated for their anti-inflammatory and immunomodulatory properties against the secretion of some pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) as well as chemokines (monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2) in murine RAW 264.7 macrophages.

MATERIALS AND METHODS

The inhibitory effects of aqueous and ethanol extracts were determined using cytokine multiplex-bead assays in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 cells.

RESULTS

Overall, the ethanol extracts were more potent cytokine inhibitors compared to the aqueous extracts. The LPS-stimulated cells treated with the ethanol extracts of Erythrina lysistemon Hutch., Pterocelastrus rostratus Walp. Syzygium cordatum Hochst. ex Krauss and Warburgia salutaris (G. Bertol.) Chiov., demonstrated significant (p < 0.005) inhibition up to 85% of IL-1β, IL-6, and TNF-α secretion compared to the LPS control. Additionally, P. rostratus and S. cordatum aqueous bark extracts substantially decreased the secretion of all the tested cytokines and chemokines. Chemical investigation of the S. cordatum extract resulted in the identification of four ellagic acid derivatives: ellagic acid 4-O-α-rhamnopyranoside (1), ellagic acid 4-O-α-4″-acetylrhamnopyranoside (2), 3-O-methylellagic acid 4'-O-α-3″-O-acetylrhamnopyranoside (3) and 3-O-methylellagic acid 4'-O-α-4″-O-acetylrhamnopyranoside (4), along with mixtures of ellagic acid 4-O-α-2″-acetylrhamnopyranoside (5), ellagic acid 4-O-α-3″-acetylrhamnopyranoside (6) and ellagic acid (7). Their structures were confirmed by mass spectrometry, NMR spectroscopy, and comparison with data from literature.

CONCLUSION

The cytokine inhibition properties of most of the medicinal plants screened herein are reported for the first time. Our results provide insights into the mechanism of action by which the selected southern African medicinal plants regulate inflammation.

MerTK-dependent efferocytosis by monocytic-MDSCs mediates resolution of post-lung transplant injury

Rationale

Patients with end stage lung diseases require lung transplantation (LTx) that can be impeded by ischemia-reperfusion injury (IRI) leading to subsequent chronic lung allograft dysfunction (CLAD) and inadequate outcomes.

Objectives

We examined the undefined role of MerTK (receptor Mer tyrosine kinase) on monocytic myeloid-derived suppressor cells (M-MDSCs) in efferocytosis (phagocytosis of apoptotic cells) to facilitate resolution of lung IRI.

Methods

Single-cell RNA sequencing of lung tissue and BAL from post-LTx patients was analyzed. Murine lung hilar ligation and allogeneic orthotopic LTx models of IRI were used with Balb/c (WT), cebpb -/- (MDSC-deficient), Mertk -/- or MerTK-CR (cleavage resistant) mice. Lung function, IRI (inflammatory cytokine and myeloperoxidase expression, immunohistology for neutrophil infiltration), and flow cytometry of lung tissue for efferocytosis of apoptotic neutrophils were assessed in mice.

Measurements and Main Results

A significant downregulation in MerTK-related efferocytosis genes in M-MDSC populations of CLAD patients compared to healthy subjects was observed. In the murine IRI model, significant increase in M-MDSCs, MerTK expression and efferocytosis was observed in WT mice during resolution phase that was absent in cebpb -/- Land Mertk -/- mice. Adoptive transfer of M-MDSCs in cebpb -/- mice significantly attenuated lung dysfunction, and inflammation leading to resolution of IRI. Additionally, in a preclinical murine orthotopic LTx model, increases in M-MDSCs were associated with resolution of lung IRI in the transplant recipients. In vitro studies demonstrated the ability of M-MDSCs to efferocytose apoptotic neutrophils in a MerTK-dependent manner.

Conclusions

Our results suggest that MerTK-dependent efferocytosis by M-MDSCs can significantly contribute to the resolution of post-LTx IRI.

Bergamot Byproducts: A Sustainable Source to Counteract Inflammation

Chronic inflammation is the result of an acute inflammatory response that fails to eliminate the pathogenic agent or heal the tissue injury. The consequence of this failure lays the foundations to the onset of several chronic ailments, including skin disorders, respiratory and neurodegenerative diseases, metabolic syndrome, and, eventually, cancer. In this context, the long-term use of synthetic anti-inflammatory drugs to treat chronic illnesses cannot be tolerated by patients owing to the severe side effects. Based on this, the need for novel agents endowed with anti-inflammatory effects prompted to search potential candidates also within the plant kingdom, being recognized as a source of molecules currently employed in several therapeutical areas. Indeed, the ever-growing evidence on the anti-inflammatory properties of dietary polyphenols traced the route towards the study of flavonoid-rich sources, such as Citrus bergamia (bergamot) and its derivatives. Interestingly, the recent paradigm of the circular economy has promoted the valorization of Citrus fruit waste and, in regard to bergamot, it brought to light new evidence corroborating the anti-inflammatory potential of bergamot byproducts, thus increasing the scientific knowledge in this field. Therefore, this review aims to gather the latest literature supporting the beneficial role of both bergamot derivatives and waste products in different models of inflammatory-based diseases, thus highlighting the great potentiality of a waste re-evaluation perspective.

The role and mechanism of action of microbiota-derived short-chain fatty acids in neutrophils: From the activation to becoming potential biomarkers

Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, have emerged as critical mediators in the communication between the human microbiota and its host. As the first responder to the inflammatory site, neutrophils play an important role in protecting the host against bacterial infections. Recent investigations revealed that SCFAs generated from microbiota influence various neutrophil activities, including activation, migration, and generation of mediators of inflammatory processes. SCFAs have also been demonstrated to exhibit potential therapeutic benefits in a variety of disorders related to neutrophil dysfunction, including inflammatory bowel disease, viral infectious disorders, and cancer. This study aims to examine the molecular processes behind the complicated link between SCFAs and neutrophils, as well as their influence on neutrophil-driven inflammatory disorders. In addition, we will also provide an in-depth review of current research on the diagnostic and therapeutic value of SCFAs as possible biomarkers for neutrophil-related diseases.

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.

Proteomic analysis of the hepatic response to a pollutant mixture in mice. The protective action of selenium

Metals and pharmaceuticals contaminate water and food worldwide, forming mixtures where they can interact to enhance their individual toxicity. Here we use a shotgun proteomic approach to evaluate the toxicity of a pollutant mixture (PM) of metals (As, Cd, Hg) and pharmaceuticals (diclofenac, flumequine) on mice liver proteostasis. These pollutants are abundant in the environment, accumulate in the food chain, and are toxic to humans primarily through oxidative damage. Thus, we also evaluated the putative antagonistic effect of low-dose dietary supplementation with the antioxidant trace element selenium. A total of 275 proteins were affected by PM treatment. Functional analyses revealed an increased abundance of proteins involved in the integrated stress response that promotes translation, the inflammatory response, carbohydrate and lipid metabolism, and the sustained expression of the antioxidative response mediated by NRF2. As a consequence, a reductive stress situation arises in the cell that inhibits the RICTOR pathway, thus activating the early stage of autophagy, impairing xenobiotic metabolism, and potentiating lipid biosynthesis and steatosis. PM exposure-induced hepato-proteostatic alterations were significantly reduced in Se supplemented mice, suggesting that the use of this trace element as a dietary supplement may at least partially ameliorate liver damage caused by exposure to environmental mixtures.

Immunity-on-a-Chip: Integration of Immune Components into the Scheme of Organ-on-a-Chip Systems

Studying the immune system in vitro aims to understand how, when, and where the immune cells migrate/differentiate and respond to the various triggering events and the decision points along the immune response journey. It becomes evident that organ-on-a-chip (OOC) technology has a superior capability to recapitulate the cell-cell and tissue-tissue interaction in the body, with a great potential to provide tools for tracking the paracrine signaling with high spatial-temporal precision and implementing in situ real-time, non-destructive detection assays, therefore, enabling extraction of mechanistic information rather than phenotypic information. However, despite the rapid development in this technology, integration of the immune system into OOC devices stays among the least navigated tasks, with immune cells still the major missing components in the developed models. This is mainly due to the complexity of the immune system and the reductionist methodology of the OOC modules. Dedicated research in this field is demanded to establish the understanding of mechanism-based disease endotypes rather than phenotypes. Herein, we systemically present a synthesis of the state-of-the-art of immune-cantered OOC technology. We comprehensively outlined what is achieved and identified the technology gaps emphasizing the missing components required to establish immune-competent OOCs and bridge these gaps.

Effect of stretching on inflammation in a subcutaneous carrageenan mouse model analyzed at single-cell resolution

Understanding the factors that influence the biological response to inflammation is crucial, due to its involvement in physiological and pathological processes, including tissue repair/healing, cancer, infections, and autoimmune diseases. We have previously demonstrated that in vivo stretching can reduce inflammation and increase local pro-resolving lipid mediators in rats, suggesting a direct mechanical effect on inflammation resolution. Here we aimed to explore further the effects of stretching at the cellular/molecular level in a mouse subcutaneous carrageenan-inflammation model. Stretching for 10 min twice a day reduced inflammation, increased the production of pro-resolving mediator pathway intermediate 17-HDHA at 48 h postcarrageenan injection, and decreased both pro-resolving and pro-inflammatory mediators (e.g., PGE2 and PGD2 ) at 96 h. Single-cell RNA sequencing analysis of inflammatory lesions at 96 h showed that stretching increased the expression of both pro-inflammatory (Nos2) and pro-resolution (Arg1) genes in M1 and M2 macrophages at 96 h. An intercellular communication analysis predicted specific ligand-receptor interactions orchestrated by neutrophils and M2a macrophages, suggesting a continuous neutrophil presence recruiting immune cells such as activated macrophages to contain the antigen while promoting resolution and preserving tissue homeostasis.

Imbalanced serum levels of resolvin E1 (RvE1) and leukotriene B4 (LTB4) may contribute to the pathogenesis of atherosclerosis

Persistent and chronic unresolved inflammation exerts a critical role in developing atherosclerosis; however, mechanisms that prevent the resolution of inflammation in atherosclerosis are poorly delineated. This study aims to evaluate the serum levels of inflammatory high-sensitivity C-reactive protein (hsCRP), pro-inflammatory leukotriene B4 (LTB4), besides anti-inflammatory compounds, including eicosapentaenoic acid (EPA) and its derivative resolvin E1 (RvE1) in patients with atherosclerosis. Thirty-four atherosclerosis patients and thirty-two age- and sex-matched healthy individuals were included in this study. The serum levels of hsCRP, LTB4, EPA, and RvE1 were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Our results showed that the hsCRP serum levels in the three-vessel disease (3VD) subgroup of patients are significantly lower than those in the mild and single-vessel disease (SVD) subgroups (P < 0.05). Besides, the serum levels of LTB4 were meaningfully greater in patients with atherosclerosis compared to healthy controls (P < 0.05). Also, the serum EPA and RvE1 levels were significantly higher in patients than in controls (P < 0.01 and P < 0.05, respectively). However, the ratio of RvE1 to LTB4 (RvE1:LTB4) in patients was significantly reduced to that in controls (P < 0.0001). These findings illustrate that imbalanced pro-resolving RvE1 and pro-inflammatory LTB4 might contribute to failing vascular inflammation resolution and subsequent progression toward chronic inflammation in atherosclerosis.

From Inflammation to Resolution: Specialized Pro-resolving Mediators in Posttraumatic Osteoarthritis

PURPOSE OF REVIEW

To provide a comprehensive overview of the inflammatory response following anterior cruciate ligament (ACL) injury and to highlight the relationship between specialized pro-resolving mediators (SPMs) and inflammatory joint conditions, emphasizing the therapeutic potential of modulating the post-injury resolution of inflammation to prevent posttraumatic osteoarthritis (PTOA).

RECENT FINDINGS

The inflammatory response triggered after joint injuries such as ACL tear plays a critical role in posttraumatic osteoarthritis development. Inflammation is a necessary process for tissue healing, but unresolved or overactivated inflammation can lead to chronic diseases. SPMs, a family of lipid molecules derived from essential fatty acids, have emerged as active players in the resolution of inflammation and tissue repair. While their role in other inflammatory conditions has been studied, their relationship with PTOA remains underexplored. Proinflammatory mediators contribute to cartilage degradation and PTOA pathogenesis, while anti-inflammatory and pro-resolving mediators may have chondroprotective effects. Therapies aimed at suppressing inflammation in PTOA have limitations, as inflammation is crucial for tissue healing. SPMs offer a pro-resolving response without causing immunosuppression, making them a promising therapeutic option. The known onset date of PTOA makes it amenable to early interventions, and activating pro-resolving pathways may provide new possibilities for preventing PTOA progression. Harnessing the pro-resolving potential of SPMs may hold promise for preventing PTOA and restoring tissue homeostasis and function after joint injuries.

Adjunctive use of omega-3 fatty acids in combination with low-dose aspirin in periodontitis: Systematic review and meta-analysis

Periodontitis is one of the most common dental diseases with a range of treatment approaches, including pathogenetically reasonable use of various host immune modulators. One such approach is the use of omega-3 polyunsaturated fatty acids (PUFAs) in combination with low-dose aspirin. This systematic review and meta-analysis were performed to compare the standard treatment alone and adjunctive use of omega-3 PUFAs in combination with low-dose aspirin with or without standard treatment in patients with periodontitis. A systematic review of the literature was performed using MEDLINE/PubMed, Cochrane Central and Google Scholar databases. Selection criteria included the following: randomized controlled trials in subjects with periodontitis in the age group above 18 years old, with follow-up periods ranging from 6 weeks to 6 months. The meta-analysis was performed using standard methodological procedures according to Cochrane recommendations, including assessment of risk-of-bias and level of evidence (GRADE). Meta-analysis was performed for such clinical outcomes as plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP) and bleeding index (BI) based on data from seven randomized clinical trials conducted between 2010 and 2020. It was shown that adjunctive use of omega-3 PUFAs in combination with low-dose aspirin results in significant clinical improvement in PD, CAL and GI during both short and prolonged follow-up periods. The use of omega-3 PUFAs and low-dose aspirin in periodontitis patients may be promising as an adjunct therapy, however, due to a limited number of patients and significant heterogeneity, further studies need to be conducted.

Macrophage phenotypes and functions: resolving inflammation and restoring homeostasis

Inflammation must be tightly regulated to both defend against pathogens and restore tissue homeostasis. The resolution of inflammatory responses is a dynamic process orchestrated by cells of the immune system. Macrophages, tissue-resident innate immune cells, are key players in modulating inflammation. Here, we review recent work highlighting the importance of macrophages in tissue resolution and the return to homeostasis. We propose that enhancing macrophage pro-resolution functions represents a novel and widely applicable therapeutic strategy to dampen inflammation, promote repair, and restore tissue integrity and function.

(Poly)phenols: The Missing Piece in the Puzzle of Inflammation

Despite researchers' and clinicians' exponential understanding of chronic diseases' complexity, ranging from cancer, diabetes, and neurodegenerative disorders, we still have a lot of unanswered questions on pathobiology mechanisms, wherein inflammation is central [...].

Inhaled toxicants and pulmonary lipid metabolism: biological consequences and therapeutic interventions

Inhaled toxicants drive the onset of and exacerbate preexisting chronic pulmonary diseases, however, the biological mechanisms by which this occurs are largely unknown. Exposure to inhaled toxicants, both environmental and occupational, drives pulmonary inflammation and injury. Upon activation of the inflammatory response, polyunsaturated fatty acids (PUFAs) are metabolized into predominately proinflammatory lipid mediators termed eicosanoids which recruit immune cells to the site of injury, perpetuating inflammation to clear the exposed toxicants. Following inflammation, lipid mediator class-switching occurs, a process that leads to increased metabolism of hydroxylated derivates of PUFAs. These mediators, which include mono-hydroxylated PUFA derivatives and specialized proresolving lipid mediators, initiate an active process of inflammation resolution by inhibiting the inflammatory response and activating resolution pathways to return the tissue to homeostasis. Exposure to inhaled toxicants leads to alterations in the synthesis of these proinflammatory and proresolving lipid mediator pathways, resulting in greater pulmonary inflammation and injury, and increasing the risk for the onset of chronic lung diseases. Recent studies have begun utilizing supplementation of PUFAs and their metabolites as potential therapeutics for toxicant-induced pulmonary inflammation and injury. Here we will review the current understanding of the lipid mediators in pulmonary inflammation and resolution as well as the impact of dietary fatty acid supplementation on lipid mediator-driven inflammation following air pollution exposure.

The Effect of Evogliptin Tartrate on Controlling Inflammatory Pain

Background: Evogliptin tartrate inhibits dipeptidyl peptidase-4 (DPP-4), boosting glucagon-like peptide 1 (GLP-1) secretion and improving insulin release and glucose tolerance, while also exerting anti-inflammatory effects. We investigated its anti-inflammatory and analgesic effects. Methods: Forty male Sprague Dawley rats were divided into (N = 10 in each): (1) naïve, (2) complete Freund's adjuvant (CFA) inflammation + evogliptin tartrate (once for 10 mg/kg) (CFAE), (3) CFA + vehicle (same volume with normal saline with evogliptin tartrate/once) (CFAV), and (4) CFA + indomethacin (5 mg/mL/kg/1 time) (CFAI) groups. CFA was injected subcutaneously into rat plantar regions, and medications (evogliptin tartrate, vehicle, and indomethacin) were administered orally for 5 days. Post treatment, blood from the heart and plantar inflammatory tissue were collected to assess inflammatory cytokines. Evogliptin tartrate effects on controlling inflammation and pain were evaluated by measuring rat plantar paw thickness, paw withdrawal threshold, dorsal root ganglion (DRG) resting membrane potential, DRG action potential firing, and cytokine (TNF-α and IL-1β) levels. Results: Compared with the naïve group, plantar paw thickness, cytokine (TNF-α and IL-1β) levels, DRG resting membrane potential, and DRG action potential firing increased, whereas the paw withdrawal threshold decreased in all CFA groups. However, CFAE and CFAI rats showed recovery. The degree of CFAE recovery resembled that observed in the CFAI group. Conclusions: Evogliptin tartrate mirrored the anti-inflammatory pain relief of indomethacin. We aim to broaden its use as an anti-inflammatory drug or pain relief drug.

The therapeutic potential of resolvins in pulmonary diseases

Uncontrolled inflammation leads to nonspecific destruction and remodeling of tissues and can contribute to many human pathologies, including pulmonary diseases. Stimulation of inflammatory resolution is considered an important process that protects against the progression of chronic inflammatory diseases. Resolvins generated from essential omega-3 polyunsaturated fatty acids have been demonstrated to be signaling molecules in inflammation with important pro-resolving and anti-inflammatory capabilities. By binding to specific receptors, resolvins can modulate inflammatory processes such as neutrophil migration, macrophage phagocytosis and the presence of pro-inflammatory mediators to reduce inflammatory pathologies. The discovery of these pro-resolving mediators has led to a shift in drug research from suppressing pro-inflammatory molecules to investigating compounds that promote resolution to treat inflammation. The exploration of inflammatory resolution also provided the opportunity to further understand the pathophysiology of pulmonary diseases. Alterations of resolution are now linked to both the development and exacerbation of diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, acute respiratory distress syndrome, cancer and COVID-19. These findings have resulted in the rise of novel design and testing of innovative resolution-based therapeutics to treat diseases. Hence, this paper reviews the generation and mechanistic actions of resolvins and investigates their role and therapeutic potential in several pulmonary diseases that may benefit from resolution-based pharmaceuticals.

Mesenchymal stem cells paracrine proteins from three-dimensional dynamic culture system promoted wound healing in third-degree burn models

Recovery of skin function remains a significant clinical challenge for deep burns owing to the severe scar formation and poor appendage regeneration, and stem cell therapy has shown great potential for injured tissue regeneration. Here, a cell-free therapy system for deep burn skin was explored using mesenchymal stem cell paracrine proteins (MSC-PP) and polyethylene glycol (PEG) temperature-sensitive hydrogels. A three-dimensional (3D) dynamic culture system for MSCs' large-scale expansion was established using a porous gelatin microcarrier crosslinked with hyaluronic acid (PGM-HA), and the purified MSC-PP from culture supernatant was characterized by mass spectrometric analysis. The results showed the 3D dynamic culture system regulated MSCs cell cycle, reduced apoptosis, and decreased lactic acid content, and the MSC-PP produced in 3D group can promote cell proliferation, migration, and adhesion. The MSC-PP + PEG system maintained stable release in 28 days of observation in vitro. The in vivo therapeutic efficacy was investigated in the rabbit's third-degree burn model, and saline, PEG, MSC-PP, and MSC-PP + PEG treatments groups were set. The in vivo results showed that the MSC-PP + PEG group significantly improved wound healing, inhibited scar formation, and facilitated skin appendage regeneration. In conclusion, the MSC-PP + PEG sustained-release system provides a potentially effective treatment for deep burn skin healing.

From reactive species to disease development: Effect of oxidants and antioxidants on the cellular biomarkers

The influence of modern lifestyle, diet, exposure to chemicals such as phytosanitary substances, together with sedentary lifestyles and lack of exercise play an important role in inducing reactive stress (RS) and disease. The imbalance in the production and scavenging of free radicals and the induction of RS (oxidative, nitrosative, and halogenative) plays an essential role in the etiology of various chronic pathologies, such as cardiovascular diseases, diabetes, neurodegenerative diseases, and cancer. The implication of free radicals and reactive species injury in metabolic disturbances and the onset of many diseases have been accumulating for several decades, and are now accepted as a major cause of many chronic diseases. Exposure to elevated levels of free radicals can cause molecular structural impact on proteins, lipids, and DNA, as well as functional alteration of enzyme homeostasis, leading to aberrations in gene expression. Endogenous depletion of antioxidant enzymes can be mitigated using exogenous antioxidants. The current interest in the use of exogenous antioxidants as adjunctive agents for the treatment of human diseases allows a better understanding of these diseases, facilitating the development of new therapeutic agents with antioxidant activity to improve the treatment of various diseases. Here we examine the role that RS play in the initiation of disease and in the reactivity of free radicals and RS in organic and inorganic cellular components.

Loss of adenosine A3 receptors accelerates skeletal muscle regeneration in mice following cardiotoxin-induced injury

Skeletal muscle regeneration is a complex process orchestrated by multiple interacting steps. An increasing number of reports indicate that inflammatory responses play a central role in linking initial muscle injury responses to timely muscle regeneration following injury. The nucleoside adenosine has been known for a long time as an endogenously produced anti-inflammatory molecule that is generated in high amounts during tissue injury. It mediates its physiological effects via four types of adenosine receptors. From these, adenosine A3 receptors (A3Rs) are not expressed by the skeletal muscle but are present on the surface of various inflammatory cells. In the present paper, the effect of the loss of A3Rs was investigated on the regeneration of the tibialis anterior (TA) muscle in mice following cardiotoxin-induced injury. Here we report that regeneration of the skeletal muscle from A3R-/- mice is characterized by a stronger initial inflammatory response resulting in a larger number of transmigrating inflammatory cells to the injury site, faster clearance of cell debris, enhanced proliferation and faster differentiation of the satellite cells (the muscle stem cells), and increased fusion of the generated myoblasts. This leads to accelerated skeletal muscle tissue repair and the formation of larger myofibers. Though the infiltrating immune cells expressed A3Rs and showed an increased inflammatory profile in the injured A3R-/- muscles, bone marrow transplantation experiments revealed that the increased response of the tissue-resident cells to tissue injury is responsible for the observed phenomenon. Altogether our data indicate that A3Rs are negative regulators of injury-related regenerative inflammation and consequently also that of the muscle fiber growth in the TA muscle. Thus, inhibiting A3Rs might have a therapeutic value during skeletal muscle regeneration following injury.

Single-cell Transcriptional Analysis of the Cellular Immune Response in the Oral Mucosa of Mice

Periodontal health is dependent on a symbiotic relationship of the host immune response with the oral microbiota. Pathologic shifts of the microbial plaque elicit an immune response that eventually leads to the recruitment and activation of osteoclasts and matrix metalloproteinases and the eventual tissue destruction that is evident in periodontal disease. Once the microbial stimulus is removed, an active process of inflammatory resolution begins. The goal of this work was to use scRNAseq to demonstrate the unique cellular immune response across three distinct conditions of periodontal health, disease, and resolution using mouse models. Periodontal disease was induced using a ligature model. Resolution was modeled by removing the ligature and allowing the mouse to recover. Immune cells (Cd45+) were isolated from the periodontium and analyzed via scRNAseq. Gene signature shifts across the three conditions were characterized and shown to be largely driven by macrophage and neutrophils during the periodontal disease and resolution conditions. Resolution of periodontal disease was characterized by the differential regulation of unique gene subsets. Clustering analysis characterized multiple cellular subpopulations within B Cells, macrophages, and neutrophils that demonstrated differential expansion and contraction across conditions of periodontal health, disease, and resolution. Interestingly, we identified a transcriptionally distinct macrophage subpopulation that expanded during the resolution condition and demonstrated an immunoregulatory gene signature. We identified a cell surface marker for this resolution-associated macrophage subgroup (Cd74) and validated the expansion of this subgroup during resolution via flow cytometry. This work presents a robust immune cell atlas for study of the immunological changes in the oral mucosa during three distinct conditions of periodontal health, disease, and resolution and it improves our understanding of the cellular and molecular markers that characterize health from disease for the development of future diagnostics and therapies.

cFLIPS regulates alternative NLRP3 inflammasome activation in human monocytes

The innate immune responses, including inflammasome activation, are paramount for host defense against pathogen infection. In contrast to canonical and noncanonical inflammasome activation, in this study, heat-killed gram-negative bacteria (HK bacteria) were identified as single-step stimulators of the NLRP3 inflammasome in human monocytes, and they caused a moderate amount of IL-1β to be released from cells. Time course experiments showed that this alternative inflammasome response was finished within a few hours. Further analysis showed that the intrinsically limited NLRP3 inflammasome activation response was due to the negative regulation of caspase-8 by the short isoform of cFLIP (cFLIPs), which was activated by NF-κB. In contrast, overexpressed cFLIPS, but not overexpressed cFLIPL, inhibited the activation of caspase-8 and the release of IL-1β in response to HK bacteria infection in human monocytes. Furthermore, we demonstrated that TAK1 activity mediated the expression of cFLIPs and was upstream and essential for the caspase-8 cleavage induced by HK bacteria in human monocytes. The functional specificity of cFLIPs and TAK1 revealed unique responses of human monocytes to a noninvasive pathogen, providing novel insights into an alternative regulatory pathway of NLRP3 inflammasome activation.