Search Results (89)

Oxidative stress is a key driver of chronic inflammatory diseases. Anodendron affine is a native Formosan plant species in Taiwan that remains largely underexplored phytochemically and bioactivity. To reveal the bioactive constituents and assess its potential as a source of anti-inflammatory antioxidants, we performed bioactivity-guided fractionation and evaluated the inhibition of superoxide anion (O₂^•–) generation in formyl-L-methionyl-L-leucyl-L-phenylalanine-stimulated human neutrophils. Molecular docking simulations were employed to model interactions with Formyl peptide receptor 1 (FPR1) and the Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex, including neutrophil cytosol factor 1 (p47phox) and NADPH oxidase 2 (NOX2), to propose a theoretical mechanism of action. Phytochemical investigation led to the isolation of two new compounds, methyl 4,5-O-diferuloyl-3-methoxyquinate (1) and 16-pregnen-3,12,20-trione (2), together with four known compounds. Notably, 4-hydroxy-3-prenylbenzoic acid (5) exhibited potent inhibitory activity (IC₅₀ = 17.65 ± 0.97 μM), surpassing the activity of the positive control, ibuprofen (IC₅₀ = 27.85 ± 3.56 μM). Docking studies suggested that anodendrosin H (4) and 4-hydroxy-3-prenylbenzoic acid (5) exhibit high predicted binding affinity to p47phox and NOX2. Based on these results, compounds 1, 4, and 5 from A. affine were identified as potential lead candidates for the development of novel anti-inflammatory therapeutics. Full article

Objectives: Periodontitis is a multifactorial inflammatory disease initiated by pathogenic bacteria, such as Porphyromonas gingivalis. Resolvin D1 (RvD1) plays a pivotal role in inflammation resolution. This study aimed to identify the mechanism of the regulatory effects of RvD1 on the inflammatory response of human periodontal ligament cells (hPDLCs). Methods: To investigate the mechanism of RvD1’s impact on the hPDLCs, RNA-sequencing (RNA-seq) was used and differentially expressed genes (DEGs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to assess the signaling pathways in which NF-κB and MAPK were determined to play a significant role. Alterations in NF-κB and MAPK pathways were verified by immunofluorescence (IF), quantitative real-time PCR (qRT-PCR), and Western blotting (WB). The expression of RvD1 and lipoxin A4/formyl peptide receptor 2 (ALX/FPR2) was assessed by IF and WB. Inflammatory cytokine interleukin (IL) 6 and IL-1β release was measured by ELISA. Results: GO and KEGG analyses indicated that RvD1 regulates the inflammatory process in PDLCs primarily via TLR4-MyD88-mediated NF-κB and MAPK signaling. RvD1 suppressed lipopolysaccharide (LPS)-induced TLR4 and MyD88 expression, inhibited phosphorylation of NF-κB p65 and its inhibitor IKBKB, and attenuated phosphorylation of p38 MAPK, ERK, and JNK. ALX/FPR2 was expressed on hPDLCs and was further upregulated upon treatment with RvD1. RvD1 significantly down-regulated the IL-6 and IL-1β levels in LPS-stimulated hPDLCs. Conclusions: RvD1 regulates the inflammatory response of LPS-stimulated hPDLCs by the TLR4-MyD88-MAPK and TLR4-MyD88-NF-κB signaling pathways, suggesting the potential role of RvD1 in restoring periodontal tissue homeostasis by regulating PDLC response to inflammatory and infectious stimuli. Full article

Pain is a multifactorial phenomenon involving neuronal, immune, and glial components. Annexin A1 (AnxA1), a glucocorticoid-regulated protein with pro-resolving properties, has emerged as a critical modulator of pain. Present in both peripheral and central compartments, AnxA1 acts through the formyl peptide receptor FPR2/ALX to regulate immune responses, modulate nociceptive signaling, and promote tissue homeostasis. Its mimetic peptide, Ac_2–26, has demonstrated robust antinociceptive effects in various pain models, including those induced by inflammation, tissue injury, viral infection, and opioid exposure. AnxA1 modulates cytokine expression, inhibits pro-nociceptive pathways such as TRPV1 and CXCL12/CXCR4, and reprograms macrophages. In the central nervous system, it attenuates neuroinflammation and central sensitization. Notably, AnxA1 can exhibit context-dependent effects, contributing to either the resolution or exacerbation of inflammation. This review examines the molecular mechanisms by which AnxA1 bridges the immune and nervous system pathways, highlighting its therapeutic potential in pain management. Full article

Crotoxin (CTX), the main toxin in Crotalus durissus terrificus venom, is a heterodimeric complex known for its antitumoral, anti-inflammatory, and immunomodulatory properties. In macrophages, CTX stimulates energy metabolism, pro-inflammatory cytokines, superoxide production, and lipoxin A₄ secretion while inhibiting macrophage spreading and phagocytosis. These effects are completely blocked by Boc-2, a selective formyl peptide receptors (FPRs) antagonist. Despite the correlation between FPRs and CTX-mediated effects, their involvement in mediating CTX entry into macrophages remains unclear. This study aimed to investigate the involvement of FPRs in CTX entry into monocytes and macrophages. For this, THP-1 cells were silenced for FPRs or treated with Boc-2. Results demonstrated that FPR-related signaling pathways, which influence macrophage functions such as ROS release, phagocytosis, and spreading, were reduced in FPR-silenced cells. However, even in the absence of FPRs, CTX was efficiently internalized by macrophages. These findings suggest that FPRs are essential for the immunomodulatory effects of CTX, but are not involved in CTX internalization. Full article

In physiological situations involving cell damage, molecules derived from mitochondria or bacteria are produced. These molecules are known as N-formyl peptides and are detected by formyl peptide receptors (FPRs), which stimulate immune cells to migrate to the specific site of injury or infection. Despite their initially beneficial effects on health, N-formyl peptides also contribute to the development or exacerbation of chronic non-communicable diseases. Therefore, understanding the metabolic pathways related to the involvement of N-formyl peptides and FPRs may increase our ability to regulate immune responses and precisely target FPRs with personalized strategies, offering a promising approach for the treatment of specific diseases. In this way, bioactive compounds in food may influence N-formyl peptides, interacting with the receptors either competitively or by inhibiting them, which affects the inflammatory response and oxidative reactions of cells. This review examines the pathways associated with forming N-formyl peptides, the activation of FPRs, and the roles of bioactive compounds in regulating N-formyl peptides. Full article

Chronic neuroinflammation and oxidative stress play an important role in the onset and progression of neurodegenerative disorders, including Alzheimer’s disease, which can ultimately lead to neuronal damage and loss. The mechanisms of sustained neuroinflammation and the coordinated chain of events that initiate, modulate, and then lead to the resolution of inflammation are increasingly being elucidated, offering alternative approaches for treating pathologies with underlying chronic neuroinflammation. Here, we propose a new multitarget approach to address chronic neuroinflammation and oxidative stress in neurodegenerative disorders by activating the formyl peptide receptor 2 (FPR2) combined with the potentiation of hydrogen sulfide (H₂S) release. FPR2 is a key player in the resolution of inflammation because it mediates the effects of several endogenous pro-resolving mediators. At the same time, H₂S is an endogenous gaseous transmitter with anti-inflammatory and pro-resolving properties, and it can protect against oxidative stress. Starting from potent FPR2 agonists identified in our laboratories, we prepared hybrid compounds by embedding an H₂S-donating moiety within the molecular scaffold of these FPR2 agonists. Following this approach, we identified several compounds that combined potent FPR2 agonism with the ability to release H₂S. The release of H₂S was assessed in buffer and intracellularly. Compounds 7b and 8b combined potent FPR2 agonist activity, selectivity over FPR1, and the ability to release H₂S. Compounds 7b and 8b were next studied in murine primary microglial cells stimulated with lipopolysaccharide (LPS), a widely accepted in vitro model of neuroinflammation. Both compounds were able to counterbalance LPS-induced cytotoxicity and the release of pro-inflammatory (IL-18, IL-6) and anti-inflammatory (IL-10) cytokines induced by LPS stimulation. Full article

Background: the treatment of squamous cell carcinomas of the oral cavity (OSCCs) is limited by the lack of reliable diagnostic/prognostic, and predictive markers, as well as by intrinsic tumor cell heterogeneity. 5-azacytidine (5-AZA) offers opportunities for cancer cell reprogramming to develop new target-specific treatments. The protein annexin A1 (ANXA1) is downregulated in head and neck squamous cell carcinoma (HNSCC), correlated with pathological differentiation grade. Objectives: this work aimed to further investigate the role of ANXA1 in OSCC progression based on 5-AZA activity. Methods: we used CAL27 and CAL33 cell lines, which differ in drug sensitivity and differentiation status. Results: CAL27 showed a higher expression of the stemness markers compared to CAL33 cells, but this positivity was lost after treatment with 5-AZA. This drug also decreased CAL27 cell motility, promoting a less aggressive phenotype. Moreover, 5-AZA increased ANXA1 expression only in CAL27. After siRNA-mediated downmodulation, we witnessed a significant rise in cell motility and the inversion of E-/N-cadherin expression, which was reverted again by 5-AZA. To investigate the role of exogenous ANXA1 derived from the tumor microenvironment, we treated CAL27 with Ac2-26, an ANXA1 mimetic peptide. Interestingly, we found that this peptide alone showed impacts similar to 5-AZA in reversing the aggressive phenotype. All these effects were not evidenced in CAL33 cells. Finally, to prove the loop of the exogenous protein, we detected increased expression of its receptors, formyl peptide receptors (FPRs), and their activation, leading to oncosuppressor effects. Conclusions: we propose that ANXA1 mediates the effects of 5-AZA only in poorly differentiated stemlike CAL27 cell lines. This suggests the relevance of ANXA1 as a diagnostic/prognostic biomarker in OSCCs, paving the way for personalized therapies to overcome treatment difficulties. Full article

The acute phase response is a hallmark of all inflammatory reactions and acute phase reactants, such as C-reactive protein (CRP) and serum amyloid A (SAA) proteins, are among the most useful plasma and serum markers of inflammation in clinical medicine. Although it is well established that inflammatory cytokines, mainly interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) induce SAA in the liver, the biological functions of elicited SAA remain an enigma. By the classical multi-step protein purification studies of chemotactic factors present in plasma or serum, we discovered novel chemokines and SAA1 fragments, which are induced during inflammatory reactions. In contrast to earlier literature, pure SAA1 fails to induce chemokines, an ascribed function that most probably originates from contaminating lipopolysaccharide (LPS). However, intact SAA1 and fragments thereof synergize with CXC and CC chemokines to enhance chemotaxis. Natural SAA1 fragments are generated by inflammatory proteinases such as matrix metalloproteinase-9 (MMP-9). They mediate synergy with chemokines by the interaction with cognate G protein-coupled receptors (GPCRs), formyl peptide receptor 2 (FPR2) and (CC and CXC) chemokine receptors. In conclusion, SAA1 enforces the action of many chemokines and assists in local leukocyte recruitment, in particular, when the concentrations of specifically-induced chemokines are still low. Full article

Background: The brain is protected from invading pathogens by the blood−brain barrier (BBB) and the innate immune system. Pattern recognition receptors play a crucial role in detecting bacteria and initiating the innate immune response. Among these are G-protein-coupled formyl peptide receptors (FPR), which are expressed by immune cells in the central nervous system. In this study, we investigated the influence of the FPR ligand Ac2-26 on the integrity of the BBB during pneumococcal meningitis. Methods: Wild-type (WT) and Fpr1- and Fpr2-deficient mice were intrathecally infected with Streptococcus pneumoniae. Subsequently, different groups of mice were treated with intraperitoneal injections of Ac2-26. The integrity of the BBB was analyzed using various markers through immunohistochemistry and immunofluorescence. Results: The results showed reduced BBB integrity during the course of bacterial meningitis. Treatment with Ac2-26 in WT mice significantly prolonged the maintenance of BBB integrity. However, this effect was not observed in Fpr2-deficient mice. Conclusions: This study extends previous findings on the anti-inflammatory properties of Ac2-26 by demonstrating that Ac2-26 positively affects BBB integrity via FPR2 during pneumococcal meningitis. These findings suggest that further investigation of Ac2-26 and other FPR modulators as potential therapies for Streptococcus pneumoniae-induced meningitis is warranted. Full article

Sex differences are a complex and crucial variable in developing and progressing metabolic and cardiovascular disease pathophysiology and clinical outcomes. The female sex, compared to the male sex, is protected from metabolic disturbances and their resulting cardiovascular events. However, the peculiar life phases associated with females, such as puberty, pregnancy, and premenopausal and menopausal stages, are all associated with different risks for the development of cardiovascular disease (CVD). Metabolic dysfunction-associated steatotic liver disease (MASLD), a condition of hepatic steatosis, and at least one feature of metabolic syndrome is associated with an increased risk of cardiovascular events. The risk of MASLD and its progression to the development of CVD differs between men and women. Differences in several factors, including formyl peptide receptor (FPR) 2, adipose tissue distribution, liver pyruvate kinase (LPK), and ketone body production, may underlie the sex differences in the risk of development of MASLD-induced CVD. Understanding the specific risk factors involved in the development and progression of MASLD between the sexes is crucial. This knowledge will provide important insights into the mechanisms responsible for its cardiovascular complications and can potentially lead to therapeutics targeted explicitly for each sex, offering new hope in the fight against MASLD-induced CVD. Full article

Alcohol-associated liver disease (ALD) is a prevalent medical problem with limited effective treatment strategies. Although many biological processes contributing to ALD have been elucidated, a complete understanding of the underlying mechanisms is still lacking. The current study employed a proteomic approach to identify hepatic changes resulting from ethanol (EtOH) consumption and the genetic ablation of the formyl peptide receptor 2 (FPR2), a G-protein coupled receptor known to regulate multiple signaling pathways and biological processes, in a mouse model of ALD. Since previous research from our team demonstrated a notable reduction in hepatic FPR2 protein levels in patients with alcohol-associated hepatitis (AH), the proteomic changes in the livers of Fpr2^−/− EtOH mice were compared to those observed in patients with AH in order to identify common hepatic proteomic alterations. Several pathways linked to exacerbated ALD in Fpr2^−/− EtOH mice, as well as hepatic protein changes resembling those found in patients suffering from AH, were identified. These alterations included decreased levels of coagulation factors F2 and F9, as well as reduced hepatic levels of glutamate-cysteine ligase catalytic subunit (GCLC) and total glutathione in Fpr2^−/− EtOH compared to WT EtOH mice. In conclusion, the data suggest that FPR2 may play a regulatory role in hepatic blood coagulation and the antioxidant system, both in a pre-clinical model of ALD and in human AH, however further experiments are required to validate these findings. Full article

Cancer cells exhibit high levels of oxidative stress and consequently require a high amount of cysteine for glutathione synthesis. Solute Carrier Family 7 Member 11 (SLC7A11), or xCT, mediates the cellular uptake of cystine in exchange for intracellular glutamate; imported extracellular cystine is reduced to cysteine in the cytosol through a NADPH-consuming reduction reaction. SLC7A11/xCT expression is under the control of stress-inducing conditions and of several transcription factors, such as NRF2 and ATF4. Formyl-peptide receptor 2 (FPR2) belongs to the FPR family, which transduces chemotactic signals mediating either inflammatory or anti-inflammatory responses according to the nature of its ligands and/or FPR2 binding with other FPR isoforms. The repertoire of FPR2 agonists with anti-inflammatory activities comprises WKYMVm peptide and Annexin A1 (ANXA1), and the downstream effects of the intracellular signaling cascades triggered by FPR2 include NADPH oxidase (NOX)-dependent generation of reactive oxygen species. Herein, we demonstrate that stimulation of CaLu-6 cells with either WKYMVm or ANXA1: (i) induces the redox-regulated activation of SLC7A11/xCT; (ii) promotes the synthesis of glutathione; (iii) prevents lipid peroxidation; and (iv) favors NRF2 nuclear translocation and activation. In conclusion, our overall results demonstrate that FPR2 agonists and NOX modulate SLC7A11/xCT expression and activity, thereby identifying a novel regulative pathway of the cystine/glutamate antiport that represents a new potential therapeutical target for the treatment of human cancers. Full article

Systemic Sclerosis (SSc) is a heterogeneous autoimmune disease characterized by widespread vasculopathy, the presence of autoantibodies and the progressive fibrosis of skin and visceral organs. There are still many questions about its pathogenesis, particularly related to the complex regulation of the fibrotic process, and to the factors that trigger its onset. Our recent studies supported a key role of N-formyl peptide receptors (FPRs) and their crosstalk with uPAR in the fibrotic phase of the disease. Here, we found that dermal fibroblasts acquire a proliferative phenotype after the activation of FPRs and their interaction with uPAR, leading to both Rac1 and ERK activation, c-Myc phosphorylation and Cyclin D1 upregulation which drive cell cycle progression. The comparison between normal and SSc fibroblasts reveals that SSc fibroblasts exhibit a higher proliferative rate than healthy control, suggesting that an altered fibroblast proliferation could contribute to the initiation and progression of the fibrotic process. Finally, a synthetic compound targeting the FPRs/uPAR interaction significantly inhibits SSc fibroblast proliferation, paving the way for the development of new targeted therapies in fibrotic diseases. Full article

Phospholipases (PL) A₂ catalyzes the hydrolysis of membrane phospholipids and mostly generates arachidonic acid (AA). The enzyme 5-lipoxygenase (5-LOX) can metabolize AA to obtain inflammatory leukotrienes, whose biosynthesis highly depends on cPLA2 and 5-LOX activities. Formyl Peptide Receptor 2 (FPR2) belongs to a subfamily of class A GPCRs and is considered the most versatile FPRs isoform. Signaling triggered by FPR2 includes the activation of several downstream kinases and NADPH oxidase (NOX)-dependent ROS generation. In a metabolomic analysis we observed a significant increase in AA concentration in FPR2-stimulated lung cancer cell line CaLu-6. We analyzed cPLA2 phosphorylation and observed a time-dependent increase in cPLA2 Ser505 phosphorylation in FPR2-stimulated cells, which was prevented by the MEK inhibitor (PD098059) and the p38MAPK inhibitor (SB203580) and by blocking NOX function. Similarly, we demonstrated that phosphorylation of 5-LOX at Ser271 and Ser663 residues requires FPR2-dependent p38MAPK and ERKs activation. Moreover, we showed that 5-LOX Ser271 phosphorylation depends on a functional NOX expression. Our overall data demonstrate for the first time that FPR2-induced ERK- and p38MAPK-dependent phosphorylation/activation of cPLA2 and 5-LOX requires a functional NADPH oxidase. These findings represent an important step towards future novel therapeutic possibilities aimed at resolving the inflammatory processes underlying many human diseases. Full article