Search Results (6,914)

We investigated the role of the intermediate-conductance, Ca²⁺-activated K⁺ channel K_Ca3.1 and volume-regulatory anion channel LRRC8A in regulating C-C motif chemokine ligand 2 (CCL2) expression in THP-1-differentiated M₂ macrophages (M₂-MACs), which serve as a useful model for studying tumor-associated macrophages (TAMs). CCL2 is a potent chemoattractant involved in the recruitment of immunosuppressive cells and its expression is regulated through intracellular signaling pathways such as ERK, JNK, and Nrf2 in various types of cells including macrophages. The transcriptional expression of CCL2 was suppressed in M₂-MACs following treatment with a K_Ca3.1 activator or an LRRC8A inhibitor via distinct signaling pathways: ERK–CREB2 and JNK–c-Jun pathways for K_Ca3.1, and the NOX2–Nrf2–CEBPB pathway for LRRC8A. Under in vitro conditions mimicking the elevated extracellular K⁺ concentration ([K⁺]_e) characteristic of the tumor microenvironment (TME), CCL2 expression was markedly upregulated, and this increase was reversed by treatment with them in M₂-MACs. Additionally, the WNK1–AMPK pathway was, at least in part, involved in the high [K⁺]_e-induced upregulation of CCL2. Collectively, modulating K_Ca3.1 and LRRC8A activities offers a promising strategy to suppress CCL2 secretion in TAMs, potentially limiting the CCL2-induced infiltration of immunosuppressive cells (TAMs, T_regs, and MDSCs) in the TME. Full article

Macrophages are undoubtedly one of the most widely studied cells of the immune system, among other reasons, because they are involved in a wide variety of biological processes. Deregulation of their activity is observed in a number of different disorders, including autoimmune diseases. At the same time, mammalian target of rapamycin (mTOR) is attracting increasing research attention because the pathways dependent on this kinase are activated by a variety of signals, including cytokines and proinflammatory mediators, mediate essential processes for cell survival and metabolism, and can be regulated epigenetically via microRNAs. Therefore, our narrative review aimed to summarize and discuss recent advances in the knowledge of the activation of mTOR signaling in macrophages, with a special focus on autoimmune disorders and the possibility of mTOR control by microRNAs. The summarized research observations allowed us to conclude that the effects of activity and/or inhibition of individual mTOR complexes in macrophages are largely context dependent, and therefore, these broad immunological contexts and other specific conditions should always be taken into account when attempting to modulate these pathways for therapeutic purposes. Full article

Macrophage-mediated inflammation is known to be involved in the epithelial–mesenchymal transition (EMT) of various types of cancer. This makes macrophage-derived inflammatory factors prime targets for the development of new treatments. This study uncovers the therapeutic potential and action mechanism of DAB-2-28, a small-molecule derived from para-aminobenzoic acid, in the treatment of breast cancer. The luminal MCF-7 and the triple-negative MDA-MB-231 cancer cell lines used in this study represent, respectively, breast cancers in which the differentiation states are related to the epithelial phenotype of the mammary gland and breast cancers expressing a highly aggressive mesenchymal phenotype. In MCF-7 cells, soluble factors from macrophage-conditioned media (CM-MØ) induce a characteristic morphology of mesenchymal cells with an upregulated expression of Snail1, a mesenchymal marker, as opposed to a decrease in the expression of E-cadherin, an epithelial marker. DAB-2-28 does not affect the differential expression of Snail1 and E-cadherin in response to CM-MØ, but negatively impacts other hallmarks of EMT by decreasing invasion and migration capacities, in addition to MMP9 expression and gelatinase activity, in both MCF-7 and MDA-MB-231 cells. Moreover, DAB-2-28 inhibits the phosphorylation of key pro-EMT transcriptional factors, such as NFκB, STAT3, SMAD2, CREB, and/or AKT proteins, in breast cancer cells exposed to different EMT inducers. Overall, our study provides evidence suggesting that inhibition of EMT initiation or maintenance is a key mechanism by which DAB-2-28 can exert anti-tumoral effects in breast cancer cells. Full article

Fat embolism is a critical medical emergency often resulting from long bone fractures or amputations, leading to acute respiratory distress syndrome (ARDS). The NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity, is activated by reactive oxygen species and tissue damage, contributing to inflammatory responses. This study examines the role of NLRP3 in fat embolism-induced ARDS and evaluates the therapeutic potential of MCC950, a selective NLRP3 antagonist. Fat embolism was induced by fatty micelle injection into the tail vein of Sprague Dawley rats. Pulmonary injury was assessed through lung weight gain as an edema indicator, NLRP3 expression via Western blot, and IL-1β levels using ELISA. Histological damage and macrophage infiltration were evaluated with hematoxylin and eosin staining. Fat embolism significantly increased pulmonary NLRP3 expression, lipid peroxidation, IL-1β release, and macrophage infiltration within four hours, accompanied by severe pulmonary edema. NLRP3 was localized in type I alveolar cells, co-localizing with aquaporin 5. Administration of MCC950 significantly reduced inflammatory responses, lipid peroxidation, pulmonary edema, and histological damage, while attenuating MAPK cascade phosphorylation of ERK and Raf. These findings suggest that NLRP3 plays a critical role in fat embolism-induced acute respiratory distress syndrome, and its inhibition by MCC950 may offer a promising therapeutic approach. Full article

Background/Objectives: Actinobacteria are one of the largest bacterial phyla. These microbes produce bioactive compounds, such as antifungals, antibiotics, immunological modulators, and anti-tumor agents. Studies on actinobacteria isolated from the Brazilian Savannah biome (Cerrado) are scarce and mostly address metagenomics or the search for hydrolytic enzyme-producing microbes. Solanum lycocarpum (lobeira) is a tree widely employed in regional gastronomy and pharmacopeia in Central Brazil. Methods: In this work, 60 actinobacteria isolates were purified from the rhizosphere of S. lycocarpum. Eight Streptomyces spp. isolates were selected for in vitro antifungal activity against Cryptococcus neoformans H99, the C. neoformans 89-610 fluconazole-tolerant strain, C. gattii NIH198, Candida albicans, C. glabrata, and C. parapsilosis. The ability of the aqueous extracts of the isolates to induce the in vitro secretion of tumor necrosis factor (TNF-α), nitric oxide (NO), interleukin-6 (IL-6), and IL-10 by murine macrophages was also evaluated. Results: All extracts showed antifungal activity against at least two yeast species. Streptomyces spp. LAP11, LDB2, and LDB17 inhibited C. neoformans growth by 40–93%. Most extracts (except LAP2) also inhibited C. gattii. None inhibited C. albicans, but all inhibited C. glabrata (40–90%). Streptomyces sp. LAP8 extract increased nitric oxide production by approximately 347-fold in murine macrophages, while LDB11 extract suppressed LPS-induced TNF-α production by 70% and simultaneously increased IL-10 secretion, suggesting immunosuppressive potential. Conclusions: The results revealed that Cerrado actinobacteria-derived aqueous extracts are potential sources of antifungal and immunomodulatory biocompounds. Full article

Adipose tissue inflammation contributes to obesity-induced insulin resistance. However, increasing evidence shows that high BMI (obesity) is not an accurate predictor of poor metabolic health in individuals. The molecular mechanisms regulating the metabolically activated M1 macrophage phenotype in the adipose tissues leading to insulin resistance remain largely unknown. Although the Janus Kinase (Jak)/signal transducer and activator of transcription 3 (Stat3) signaling in myeloid cells are known to promote the M2 phenotype in tumors, we demonstrate here that the Jak2/Stat3 pathway amplifies M1-mediated adipose tissue inflammation and insulin resistance under metabolic challenges. Ablating Jak2 in the myeloid compartment reduces insulin resistance in obese mice, which is associated with a decrease in infiltration of adipose tissue macrophages (ATMs). We show that the adoptive transfer of Jak2-deficient myeloid cells improves insulin sensitivity in obese mice. Furthermore, the protection of obese mice with myeloid-specific Stat3 deficiency against insulin resistance is also associated with reduced tissue infiltration by macrophages. Jak2/Stat3 in the macrophage is required for the production of pro-inflammatory cytokines that promote M1 macrophage polarization in the adipose tissues of obese mice. Moreover, free fatty acids (FFAs) activate Stat3 in macrophages, leading to the induction of M1 cytokines. Silencing the myeloid cell Stat3 with an in vivo siRNA targeted delivery approach reduces metabolically activated pro-inflammatory ATMs, thereby alleviating obesity-induced insulin resistance. These results demonstrate Jak2/Stat3 in myeloid cells is required for obesity-induced insulin resistance and inflammation. Moreover, targeting Stat3 in myeloid cells may be a novel approach to ameliorate obesity-induced insulin resistance. Full article

Background: Pain is a complex phenomenon characterized by unpleasant experiences with profound heterogeneity influenced by biological, psychological, and social factors. According to the National Health Interview Survey, 50.2 million U.S. adults (20.5%) experience pain on most days, with the annual cost of prescription medication for pain reaching approximately USD 17.8 billion. Theranostic pain nanomedicine therefore emerges as an attractive analgesic strategy with the potential for increased efficacy, reduced side-effects, and treatment personalization. Theranostic nanomedicine combines drug delivery and diagnostic features, allowing for real-time monitoring of analgesic efficacy in vivo using molecular imaging. However, clinical translation of these nanomedicines are challenging due to complex manufacturing methodologies, lack of standardized quality control, and potentially high costs. Quality by Design (QbD) can navigate these challenges and lead to the development of an optimal pain nanomedicine. Our lab previously reported a macrophage-targeted perfluorocarbon nanoemulsion (PFC NE) that demonstrated analgesic efficacy across multiple rodent pain models in both sexes. Here, we report PFC-free, biphasic nanoemulsions formulated with a biocompatible and non-immunogenic plant-based coconut oil loaded with a COX-2 inhibitor and a clinical-grade, indocyanine green (ICG) near-infrared fluorescent (NIRF) dye for parenteral theranostic analgesic nanomedicine. Methods: Critical process parameters and material attributes were identified through the FMECA (Failure, Modes, Effects, and Criticality Analysis) method and optimized using a 3 × 2 full-factorial design of experiments. We investigated the impact of the oil-to-surfactant ratio (w/w) with three different surfactant systems on the colloidal properties of NE. Small-scale (100 mL) batches were manufactured using sonication and microfluidization, and the final formulation was scaled up to 500 mL with microfluidization. The colloidal stability of NE was assessed using dynamic light scattering (DLS) and drug quantification was conducted through reverse-phase HPLC. An in vitro drug release study was conducted using the dialysis bag method, accompanied by HPLC quantification. The formulation was further evaluated for cell viability, cellular uptake, and COX-2 inhibition in the RAW 264.7 macrophage cell line. Results: Nanoemulsion droplet size increased with a higher oil-to-surfactant ratio (w/w) but was no significant impact by the type of surfactant system used. Thermal cycling and serum stability studies confirmed NE colloidal stability upon exposure to high and low temperatures and biological fluids. We also demonstrated the necessity of a solubilizer for long-term fluorescence stability of ICG. The nanoemulsion showed no cellular toxicity and effectively inhibited PGE2 in activated macrophages. Conclusions: To our knowledge, this is the first instance of a celecoxib-loaded theranostic platform developed using a plant-derived hydrocarbon oil, applying the QbD approach that demonstrated COX-2 inhibition. Full article

Activation of macrophages plays a key role in both inflammation and oxidative stress, key features of many chronic diseases. Pro-inflammatory M1-like macrophages, in particular, contribute to pro-oxidative environments and are a frequent focus of immunological research. This research examined the effects of kiwifruit allergen Act d 1, in comparison to LPS, on THP-1 macrophages in vitro differentiated under optimized conditions, both in the presence and in the absence of selected vanilloids. THP-1 monocyte differentiation was optimized by varying PMA exposure and resting time. Act d 1 induced M1-like phenotypic changes comparable to LPS, including upregulation of CD80, IL-1β and IL-6 secretion, gene expression of iNOS and NF-κB activation, in addition to increased reactive oxygen species (ROS) and catalase activity. Treatment with specific vanilloids mitigated these responses, primarily through reduced oxidative stress and NF-κB activation. Notably, vanillin (VN) was the most effective, also reducing CD80 expression and IL-1β levels. These results suggest that vanilloids can affect pro-inflammatory signaling and oxidative stress in THP-1 macrophages and highlight their potential to alter inflammatory conditions characterized by similar immune responses. Full article

Background/Objectives: The prolonged M1-like pro-inflammatory polarization of macrophages is a key factor in the delayed healing of diabetic ulcers (DU). SIRT3, a primary mitochondrial deacetylase, has been identified as a regulator of inflammation and represents a promising new therapeutic target for DU treatment. Nonetheless, the efficacy of existing SIRT3 agonists remains suboptimal. Methods: Here, we introduce a novel compound, SZC-6, demonstrating promising activity levels. Results: SZC-6 treatment down-regulated the expression of inflammatory factors in LPS-treated RAW264.7 cells and reduced the proportion of M1 macrophages. Mitosox, IF, and JC-1 staining revealed that SZC-6 preserved cellular mitochondrial homeostasis and reduced the accumulation of reactive oxygen species. In vivo experiments demonstrated that SZC-6 treatment accelerated wound healing in diabetic mice. Furthermore, HE and Masson staining revealed increased neovascularization at the wound site with SZC-6 treatment. Tissue immunofluorescence results indicated that SZC-6 effectively decreased the proportion of M1-like cells and increased the proportion of M2-like cells at the wound site. We also found that SZC-6 significantly reduced MyD88, p-IκBα, and NF-χB p65 protein levels and inhibited the nuclear translocation of P65 in LPS-treated cells. Conclusions: The study concluded that SZC-6 inhibited the activation of the NF-χB pathway, thereby reducing the inflammatory response and promoting skin healing in diabetic ulcers. SZC-6 shows promise as a small-molecule compound for promoting diabetic wound healing. Full article

Background: Human metapneumovirus (hMPV) is a respiratory pathogen that causes illness ranging from mild upper respiratory tract infections to severe pneumonia, particularly in individuals with comorbidities. Fatal cases of hMPV-induced hemorrhagic pneumonia are rare and likely under-reported. Diagnosis is often delayed due to overlapping symptoms with other respiratory viruses and the rapid progression of the disease. Case presentation: We report the case of a 55-year-old man with a complex medical history, including liver cirrhosis and diabetes mellitus, who developed acute viral pneumonia. Initial symptoms appeared three days before a sudden clinical deterioration marked by shortness of breath, hemoptysis, and respiratory failure. A nasopharyngeal swab taken on the third day of illness tested positive for hMPV by qRT-PCR. The patient died the following day. Postmortem molecular testing confirmed hMPV in lung tissue and alveolar contents. Autopsy revealed bilateral hemorrhagic pneumonia with regional lymphadenopathy. Histopathological examination showed alveolar hemorrhage, multinucleated cells, neutrophilic infiltration, activated autophagy in macrophages, and numerous cytoplasmic eosinophilic viral inclusions. Conclusions: This is the first documented case of fatal hMPV pneumonia in Armenia. It highlights the potential severity of hMPV in adults with chronic health conditions and emphasizes the need for timely molecular diagnostics. Postmortem identification of characteristic viral inclusions may serve as a cost-effective histopathological marker of hMPV-associated lung pathology. Full article

Background: Localized scleroderma (LoS) is a chronic autoimmune condition marked by cutaneous fibrosis and persistent inflammation. Modulating the activation of inflammatory cells and fibroblasts remains a central strategy in LoS treatment. We investigate the anti-fibrotic effects of Annexin A5 (AnxA5), identified as a key inflammatory component in fat extract, and assess its therapeutic efficacy. Methods: In vitro experiments were performed using TGF-β-stimulated primary human dermal fibroblasts treated with recombinant AnxA5. The anti-fibrotic effects and underlying mechanisms were assessed using CCK-8 assays, quantitative real-time PCR, Western blotting, and immunocytochemistry. In vivo, AnxA5 was administered via both preventative and therapeutic protocols in bleomycin-induced LoS mouse models. Treatment outcomes were evaluated by histological staining, collagen quantification, immunostaining, and measurement of pro-inflammatory cytokines. Results: TGF-β stimulation induced myofibroblast differentiation and extracellular matrix (ECM) production in dermal fibroblasts, both of which were significantly attenuated by AnxA5 treatment through the inhibition of phosphorylation of Smad2. In vivo, both preventative and therapeutic administration of AnxA5 effectively reduced dermal thickness, collagen deposition, ECM accumulation, M1 macrophage infiltration, and levels of pro-inflammatory cytokines. Conclusions: Through both preventative and therapeutic administration, AnxA5 ameliorates LoS by exerting dual anti-fibrotic and anti-inflammatory effects, underscoring its potential for treating fibrotic diseases. Full article

Chamaecyparis obtusa (Siebold & Zucc.) Endl. (C. obtusa) is an evergreen conifer native to temperate regions such as South Korea and Japan, traditionally used for its anti-inflammatory properties. However, the molecular mechanisms underlying the anti-inflammatory effects of C. obtusa bark extracts remain poorly understood. In this study, I compared the biological activities of C. obtusa bark extracts prepared using boiling water (COWB) and 70% ethanol (COEB), and investigated their anti-inflammatory mechanisms in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. COEB significantly suppressed both mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), along with decreased production of their respective inflammatory mediators, nitric oxide (NO) and prostaglandin E₂ (PGE₂). Additionally, COEB selectively downregulated interleukin (IL)-1β expression, without affecting tumor necrosis factor-α (TNF-α), and unexpectedly upregulated IL-6. Notably, COEB did not inhibit the LPS-induced activation of major inflammatory signaling pathways, including mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), and Janus kinase/signal transducer and activator of transcription (JAK/STAT). These findings suggest that COEB exerts anti-inflammatory effects by modulating key inflammatory mediators independently of canonical signaling pathways and may offer a novel therapeutic strategy for controlling inflammation. Full article

Osteoclastogenesis—the activation and differentiation of osteoclasts—is one of the pivotal processes of bone remodeling and is regulated by RANKL/RANK signaling, the decoy function of osteoprotegerin (OPG), and a cascade of pro- and anti-inflammatory cytokines. The disruption of this balance leads to pathological bone loss in diseases such as osteoporosis and rheumatoid arthritis. FFAR4 (Free Fatty Acid Receptor 4), a G protein-coupled receptor for long-chain omega-3 fatty acids, has been confirmed as a key mediator of metabolic and anti-inflammatory effects. This review focuses on how FFAR4 acts as the selective receptor for the omega-3 fatty acid docosahexaenoic acid (DHA). It activates two divergent signaling pathways. The Gαq-dependent cascade facilitates intracellular calcium mobilization and ERK1/2 activation. Meanwhile, β-arrestin-2 recruitment inhibits NF-κB. These collective actions reshape the cytokine environment. In macrophages, DHA–FFAR4 signaling lowers the levels of TNF-α, interleukin-6 (IL-6), and IL-1β while increasing IL-10 secretion. Consequently, the activation of NFATc1 and NF-κB p65 is profoundly suppressed under TNF-α or RANKL stimulation. Additionally, DHA modulates the RANKL/OPG axis in osteoblastic cells by suppressing RANKL expression, thereby reducing osteoclast differentiation in an inflammatory mouse model. Full article

The interleukin-20 (IL-20) cytokine subfamily, a subset of the IL-10 superfamily, includes IL-19, IL-20, IL-22, IL-24, and IL-26. Recently, their involvement in cancer biology has gained attention, particularly due to their impact on the tumor microenvironment (TME). Notably, IL-20 subfamily cytokines can exert both pro-tumorigenic and anti-tumorigenic effects, depending on the context. For example, IL-22 promotes tumor growth by enhancing cancer cell proliferation and protecting against apoptosis, whereas IL-24 demonstrates anti-tumor activity by inducing cancer cell death and inhibiting metastasis. Additionally, these cytokines influence macrophage polarization—an essential factor in the immune landscape of tumors—thereby modulating the inflammatory environment and immune evasion strategies. Understanding the dual role of IL-20 subfamily cytokines within the TME and their interactions with cancer cell hallmarks presents a promising avenue for therapeutic development. Interleukin-20 receptor antagonists are being researched for their role in cancer therapy, since they potentially inhibit tumor growth and progression. This review explores the relationship between IL-20 cytokines and key cancer-related processes, including growth and proliferative advantages, angiogenesis, invasion, metastasis, and TME support. Further research is necessary to unravel the specific mechanisms underlying their contributions to tumor progression and to determine their potential for targeted therapeutic strategies. Full article

Myxoma virus (MYXV), a rabbit-specific poxvirus and non-pathogenic in humans and mice, is an excellent candidate oncolytic virus for cancer therapy. MYXV also has immunotherapeutic benefits. In ovarian cancer (OC), immunosuppressive tumor-associated macrophages (TAMs) are key to inhibiting antitumor immunity while hindering therapeutic benefit by chemotherapy and dendritic cell (DC) vaccine. Because MYXV favors binding/entry of macrophages/monocytes, we examined the therapeutic potential of MYXV against TAMs. We found previously that a replication-defective MYXV with targeted deletion of an essential gene, M062R, designated ΔM062R MYXV, activated both the host DNA sensing pathway and the SAMD9 pathway. Treatment with ΔM062R confers therapeutic benefit comparable to that of wild-type replicating MYXV in preclinical models. Here we found that ΔM062R MYXV, when integrated with cisplatin and DC immunotherapy, further improved treatment benefit, likely through promoting tumor antigen-specific T cell function. Moreover, we also tested ΔM062R MYXV in targeting human immunosuppressive TAMs from OC patient ascites in a co-culture system. We found that ΔM062R treatment subverted the immunosuppressive properties of TAMs and elevated the avidity of cytokine production in tumor antigen-specific CD4⁺ T cells. Overall, ΔM062R presents a promising immunotherapeutic platform as a beneficial adjuvant to chemotherapy and DC vaccine. Full article