Search Results (121)

Systemic lupus erythematosus (SLE) is characterized by autoimmune dysregulation, elevated autoantibody production, and persistent inflammation, predisposing patients to atherosclerosis (AS). Atherogenesis is dependent on lipid homeostasis and inflammatory processes, with the formation of lipid-laden, macrophage-derived foam cells (MDFC) essential for atherosclerotic lesion progression. Elevated cholesterol levels within lipid rafts trigger heightened pro-inflammatory responses in macrophages via Toll-like receptor 9 (TLR9). Artesunate (ART), an artemisinin derivative sourced from Artemisia annua, exhibits therapeutic potential in modulating inflammation and autoimmune conditions. Nonetheless, its impact and mechanisms in SLE-associated AS (SLE-AS) remain largely unexplored. Our investigation demonstrated that ART could effectively ameliorate lupus-like symptoms and atherosclerotic plaque development in SLE-AS mice. Moreover, ART enhanced cholesterol efflux from MDFC by upregulating ABCA1, ABCG1, and SR-B1 both in vivo and in vitro. Moreover, ART reduced cholesterol accumulation in bone marrow-derived macrophages (BMDMs), thereby diminishing TLR9 recruitment to lipid rafts. ART also suppressed TLR9 expression and its downstream effectors in the kidney and aorta of SLE-AS mice, attenuating the TLR9-mediated inflammatory cascade in CPG2395 (ODN2395)-stimulated macrophages. Through bioinformatics analysis and experimental validation, PPARγ was identified as a pivotal downstream mediator of ART in macrophages. Depleting PPARγ levels reduced the expression of ABCA1, ABCG1, and SR-B1 in macrophages, consequently impeding cholesterol efflux. In conclusion, these findings suggest that ART ameliorates SLE-AS by restoring cholesterol homeostasis through the PPARγ-ABCA1/ABCG1/SR-B1 pathway and suppressing lipid raft-driven TLR9/MyD88 inflammation. Full article

Hypertension (HTN) is a major contributor to global morbidity and manifests in several variants, including salt-sensitive hypertension (SSHTN). SSHTN is defined by an increase in blood pressure (BP) in response to high dietary salt, and is associated with heightened cardiovascular risk, renal damage, and immune system activation. However, the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) has not yet been explored in the context of SSHTN. Previously, we reported that GM-CSF is critical in priming bone marrow-derived (BMD)-macrophages (BMD-Macs) and BMD-dendritic cells (BMD-DCs) to become activated (CD38+) in response to salt. Further exploration revealed these cells differentiated into BMD-M1 Macs, CD38+ BMD-M1 Macs, BMD-type-2 conventional DCs (cDC2s), and CD38+ BMD-cDC2s. Additionally, BMD-monocytes (BMDMs) grown with GM-CSF and injected into SSHTN mice traffic to the kidneys and differentiate into Macs, CD38+ Macs, DCs, and CD38+ DCs. In the current study, we treated SSHTN mice with an anti-GM-CSF antibody (aGM) and found that preventive aGM treatment mitigated BP, prevented renal inflammation, and altered renal immune cells. In mice with established SSHTN, aGM treatment attenuated BP, reduced renal inflammation, and differentially affected renal immune cells. Adoptive transfer of aGM-treated BMDMs into SSHTN mice resulted in decreased renal trafficking. Additionally, aGM treatment of BMD-Macs, CD38+ BMD-M1 Macs, BMD-DCs, and CD38+ BMD-cDC2s led to decreased pro-inflammatory gene expression. These findings suggest that GM-CSF plays a role in SSHTN and may serve as a potential therapeutic target. Full article

Infections with the protozoan Neospora caninum cause abortion in cattle, likely due to the parasite’s replication and excessive inflammation in the placenta. Cathelicidins are host defense peptides known for their antimicrobial and immunomodulatory functions, but their role in N. caninum infections remains elusive. Using bone marrow-derived macrophages (BMDMs) isolated from mice expressing (wild-type, Camp^+/+) and lacking (Camp^−/−) cathelicidins, we investigated the role of endogenous cathelicidin in infections with N. caninum. We show that Camp^−/− macrophages primed with lipopolysaccharide (LPS) had an increased number of intracellular N. caninum tachyzoites, and these macrophages released higher amounts of IL-1β and lactate dehydrogenase (LDH), a marker of cytotoxicity. These findings indicate that cathelicidins contribute to intracellular N. caninum control and inflammation by limiting the activation of the inflammasome, particularly under LPS-induced conditions. This insight reveals the immunomodulatory role of cathelicidins in controlling N. caninum-associated pathologies. Full article

Five new natural products, including two sorbicillinoids (1–2), one indolinone alkaloid (10), one tetracyclic steroid (11), and one α-pyrone derivative (14), were identified from the endophytic Penicillium sp. NX-S-6, together with thirteen known natural products. The structures of new compounds were unambiguously elucidated by comprehensive spectroscopic analyses (NMR, MS), as well as electronic circular dichroism (ECD) calculation. Notably, quinosorbicillinol (1) was identified as a rare hybrid sorbicillinoid incorporating a quinolone moiety, representing a unique structural scaffold in this natural product class. Biological evaluation revealed that Compounds 1, 4 and 8 potently inhibited the production of nitric oxide and interleukin 6 in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Mechanistic studies furthermore demonstrated that Compounds 4 and 8 effectively suppressed interleukin-1β secretion in LPS-induced immortalized mouse bone marrow-derived macrophages (iBMDMs) by blocking NLRP3 inflammasome activation. This inhibition was attributed to their ability to disrupt the assembly of the NLRP3-caspase-1 complex, a key event in the pathogenesis of inflammatory disorders. These findings not only expand the structural diversity of endophyte-derived natural products but also highlight their potential as lead compounds for developing anti-inflammatory therapeutics targeting the NLRP3 pathway. Full article

Immunotherapy is a transformative strategy in oncology, yet the development of novel immunomodulatory agents remains essential. This study explores the anti-tumor potential of a structurally unique polysaccharide isolated from an Aspergillus ochraceus (AOP), sourced from the Antarctic Weddell Sea. Using alkaline-assisted extraction and chromatographic purification, we obtained a homogeneous polysaccharide predominantly composed of galactose and mannose, with an average molecular weight of 39.67 kDa. The structure was characterized by an integrated nuclear magnetic resonance spectroscopy and mass spectrometry analysis, revealing that the AOP is composed of β (1→5)-linked galactofuranose units, with a minor substitution by α-D-mannopyranose residues via (1→2) glycosidic bonds at the C2 of the galactofuranose. Functional assays, including CCK8 and wound-healing tests, demonstrated that this polysaccharide, referred to as AOP, inhibited melanoma cell proliferation and migration in a dose-dependent manner. Additionally, the AOP activated RAW264.7 and bone marrow-derived macrophage (BMDM) cells without exhibiting significant cytotoxicity, leading to the release of inflammatory factors such as TNF-α, IL-1β, and IL-6. Mechanistically, the AOP was found to upregulate the expression of CD86 and IFN-γ, while downregulating genes like IL-4 and Arg1. These findings position the AOP as the first documented Antarctic fungal polysaccharide with macrophage-reprogramming capabilities against melanoma, offering novel molecular insights for marine-derived immunotherapeutics. Full article

Background/Objectives: Neurofibromatosis type 1 (NF1) is a prevalent inherited disorder, with approximately 50% of affected individuals developing plexiform neurofibromas (PNFs), which can progress to highly aggressive malignant peripheral nerve sheath tumors (MPNSTs). While selumetinib is FDA-approved for PNFs, its efficacy in MPNSTs is limited and associated with dose-limiting toxicities. NF1 deficiency drives tumorigenesis and alters immune dynamics via RAS hyperactivation. Given the substantial macrophage infiltration in NF1 lesions and its association with disease progression, we hypothesized that targeting tumor-promoting immune cells with the retinoid X receptor (RXR) agonist MSU-42011 could be an alternative therapeutic strategy, as it has shown promise in KRAS-driven cancers by decreasing pERK levels and reducing tumor-promoting immune cells. Methods: We examined the effects of MSU-42011 and selumetinib, alone and in combination, on NF1-deficient cells and in a syngeneic MPNST model. Results: In vivo, the combination of MSU-42011 and selumetinib significantly reduced tumor growth, pERK levels, and tumor-promoting macrophages and increased activated CD8⁺ T cells in syngeneic MPNST models. In NF1-deficient cells, MSU-42011 or selumetinib reduced pERK levels, with combination treatment achieving greater reductions. Conditioned media (CM) from NF1-deficient cells increased the protein and mRNA levels of several cytokines and chemokines in human THP1 cells and bone marrow-derived macrophages (BMDMs). MSU-42011 and selumetinib, alone or in combination, partially reversed this induction. Conclusions: These findings suggest RXR agonists may have therapeutic potential against NF1, and their combination with MEK inhibitors could represent a promising strategy for NF1-associated tumors. Further studies are needed to validate these results and assess their translational relevance. Full article

Regulatory B cells (B regs) are immune cells that help suppress excessive inflammatory responses by interacting with other immune components. Among them, B-10 cells are known for their strong immunoregulatory function. This study focused on how B-10 cells influence macrophage phenotype and function through the PD-1 signaling pathway. To investigate this, B-10 cells derived from mouse spleens were co-cultured with bone marrow-derived macrophages (BMDMs) from either wild-type (WT) or PD-1 knockout (PD-1 KO) mice, using both direct contact and Transwell setups. The findings indicated that direct co-culture with B-10 cells significantly promoted the polarization of macrophages towards the anti-inflammatory M2 type, characterized by increased expression of surface markers (F4/80⁺, CD206⁺, CD163⁺), higher levels of PD-1, and upregulation of M2-related genes (IL-1ra, IL-10, Arg-1, IL-6, and CCL1). These macrophages also exhibited enhanced phagocytic activity and greater secretion of specialized pro-resolving mediator (SPMs) like RvD2 and 15-epi LXA4. In contrast, these effects were reduced when B-10 cells were cultured indirectly or when PD-1 was absent. These findings suggest that B-10 cells promote anti-inflammatory macrophage activity primarily through PD-1 signaling, offering insights into potential therapeutic approaches for controlling inflammation. Full article

Psoriasis pathogenesis involves dysregulated immune responses, yet the role of protein prenylation (particularly PGGT1B-mediated geranylgeranylation) in macrophage-driven inflammation remains poorly understood. This study aims to explore the role and molecular mechanism of protein geranylgeranyltransferase type I subunit beta (PGGT1B) in the development of psoriasis. Myeloid cell-specific PGGT1B gene knockout mice were generated, and a mouse psoriasis model was established with imiquimod to study the role and mechanism of PGGT1B gene downregulation-induced macrophage activation in the pathogenesis of psoriasis. Bone marrow-derived macrophages (BMDMs) from wild-type and PGGT1B knockout mice were cultured and stimulated with resiquimod (R848) to simulate the immune microenvironment of psoriasis. In addition, the differentially expressed genes induced by PGGT1B knockout were analyzed using RNA-seq, and bioinformatics analysis was carried out to study the possible biological process of PGGT1B regulation. Finally, PMA-THP-1 was co-cultured with HaCaT cells to study the effect of PGGT1B deletion in macrophages on the proliferation and differentiation of keratinocytes. Bone marrow PGGT1B deficiency aggravated the psoriasis-like lesions induced by imiquimod in mice. In BMDMs with PGGT1B deficiency, the NF-κB signaling pathway was over-activated by R848, and the expressions of proinflammatory cytokines IL-1β, IL-6, and TNF-α were significantly increased. Activation of cell division cycle 42 (CDC42) may mediate the activation of the NF-κB pathway in PGGT1B-deficient BMDMs. PGGT1B deletion can promote the proliferation and inhibit the differentiation of HaCaT cells. Reduced PGGT1B levels can increase the expression of CDC42, which further activates NLRP3 inflammation in macrophages through NF-κB signaling, further aggravating the inflammatory state of psoriasis. Psoriasis-like lesions induced by IMQ are aggravated when PGGT1B expression is reduced in mouse bone marrow cells. A possible mechanism for this is that PGGT1B-deficient macrophages migrate to the epidermis more easily during psoriasis, which leads to the activation of Cdc42, NF-κB signaling, and NLRP3 inflammatory corpuscles. Full article

Background: Skeletal muscle wasting is commonly observed in aging, immobility, and chronic diseases. In pathological conditions, the impairment of skeletal muscle and immune system often occurs simultaneously. Recent studies have highlighted the initiative role of skeletal muscle in interactions with immune cells. However, the impact of skeletal muscle wasting on macrophage inflammatory responses remains poorly understood. Methods: To investigate the effect of atrophic myotubes on the inflammatory response of macrophages, we established two in vitro models to induce myotube atrophy: one induced by D-galactose and the other by starvation. Conditioned medium (CM) from normal and atrophic myotubes were collected and administered to bone marrow-derived macrophages (BMDMs) from mice. Subsequently, lipopolysaccharide (LPS) stimulation was applied, and the expression of inflammatory cytokines was measured via RT-qPCR. Results: Both D-galactose and starvation treatments reduced myotube diameter and upregulated muscle atrophy-related gene expression. CM from both atrophic myotubes models augmented the gene expression of pro-inflammatory factors in BMDMs following LPS stimulation, including Il6, Il1b, and Nfkb1. Notably, CM from starvation-induced atrophic myotubes also enhanced Il12b, Tnf, and Nos2 expression in BMDMs after stimulation, a response not observed in D-galactose-induced atrophic myotubes. Conclusions: These findings suggest that CM from atrophic myotubes enhanced the expression of LPS-induced pro-inflammatory mediators in macrophages. Full article

Macrophages are key players in inflammation and immune responses due to their phenotypic plasticity. This study examined the effects of pooling donor-derived macrophages on their phenotype and function, focusing on murine bone marrow-derived macrophages (BMDMs) and human monocyte-derived macrophages (hMDMs). Murine BMDMs were generated using L929-conditioned media and compared across single and pooled donors (two-to-five mice). Similarly, hMDMs cultured with M-CSF from individual donors were compared to pooled cultures. Pooling macrophages did not alter core phenotypic markers (CD11b, F4/80, CD64) or functional outputs such as cytokine secretion and nitric oxide production. In hMDMs, pooling reduced variability and led to slightly elevated or more-uniform marker expression. These findings demonstrate that pooling macrophages minimizes inter-individual variability without compromising cellular stability or function, enhancing reproducibility in immunological research while maintaining the option of single-donor studies for personalized analyses. Full article

The P2X7 receptor is involved in innate immune responses, with its intracellular C-terminal domain capable of interacting with signaling molecules to regulate immune cell activation; however, the mechanisms underlying the signaling complexes remain unclear. To elucidate the function of the P2X7 C-terminal domain, we established bone marrow-derived macrophage (BMDM) cell lines from transgenic (Tg) mice overexpressing the C-terminal domain of P2X7 or anti-P2X7 C-terminal domain single-chain variable fragment (scFv) intrabody. In contrast to wild-type mouse BMDMs, the Tg BMDMs showed impairment of inflammatory responses induced by lipopolysaccharide (LPS) stimulation, such as NF-κB activation and subsequent TNF-α, IL-1β, and IL-6 expression. Furthermore, P2X7 was specifically associated with myeloid differentiation primary response gene 88 (MyD88) in wild-type BMDMs; its specific interaction was strongly interfered with by overexpression of the P2X7 C-terminal domain or anti-P2X7 C-terminal domain scFv in Tg BMDMs. These observations strongly suggest that P2X7 may have pivotal roles in LPS signaling cascades and could modulate macrophage inflammatory responses through its C-terminal domain. Full article

Background/Objectives: Cutibacterium acnes (C. acnes), a bacterium residing in hair follicles, triggers acne by inducing monocyte-mediated inflammatory cytokine production. Gedunin, a limonoid derived from Azadirachta indica (commonly known as neem), is renowned for its antifungal, antimalarial, anticancer, anti-inflammatory, and neuroprotective effects. However, its role in mitigating C. acnes-induced skin inflammation remains unexplored. This study investigates the anti-inflammatory effects of gedunin on C. acnes-induced skin inflammation and elucidates the underlying mechanisms. Methods: The anti-inflammatory activity of gedunin was assessed using RAW 264.7 mouse macrophage cells and mouse bone-marrow-derived macrophages (BMDMs). Key inflammatory mediators, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6), were evaluated. Mechanistic studies focused on the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, along with the NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome. An in vivo acne model was employed to examine gedunin’s therapeutic efficacy. Results: Gedunin significantly reduced the expression of IL-1β, TNF-α, iNOS, COX-2, and IL-6 in RAW 264.7 cells. It inhibited NF-κB activation without affecting the MAPK pathways, including JNK/SAPK, ERK, and p38 MAPK. Gedunin also suppressed the activation of the NLRP3 inflammasome in BMDMs. In the mouse acne model, gedunin effectively alleviated C. acnes-induced inflammation, primarily by targeting NF-κB signaling. Conclusions: Gedunin demonstrates potential as a therapeutic agent for acne treatment by targeting key inflammatory pathways, particularly NF-κB signaling. This study highlights gedunin’s promise as an alternative approach to managing C. acnes-induced skin inflammation. Full article

Our preliminary data using bone marrow-derived macrophages (BMDMs) collected from ICR mice treated with anti-sirtuin (anti-SIRT) 1 antibody showed that Brucella uptake was significantly attenuated. We then further investigated the effect of an inhibitor of SIRT1/2, cambinol, in the progression of Brucella. The in vitro results using RAW264.7 cells revealed that cambinol treatment had no effect on adhesion, uptake, intracellular survival and nitric oxide (NO) production during B. abortus infection, nor did it directly affect bacterial growth for up to 72 h. Finally, intraperitoneal treatment of 8-week-old female ICR mice infected with Brucella showed no differences in the total average weights of spleens and livers; however, the treated mice displayed higher Brucella colony-forming units (CFUs) from the spleens. Furthermore, the interleukin (IL)-10 serum level was observed to be lower in treated mice at 7 d post-infection, and none of the cytokines tested showed a change at 14 d post-infection. The overall findings showed that cambinol treatment had no effect on the proliferation of Brucella in RAW264.7 macrophages but exacerbated the splenic proliferation of the bacteria in mice and displayed reduced anti-inflammatory cytokine IL-10 at the first week of infection, suggesting that cambinol as an inhibitory of SIRT1/2 could be beneficial in the context of Brucella dissemination in animal hosts and that exploration of activating SIRTs could be an alternative treatment against Brucella infection. Full article

The class B scavenger receptor CD36 is known to bind and mediate the transport of lipid-related ligands and it functions as a pattern recognition receptor (PRR) for a variety of pathogens, including bacteria and viruses. In this study, we assessed CD36’s role as a PRR mediating pro-inflammatory effects of several known Danger-Associated Molecular Patterns (DAMPs) used either as a single preparation or as a combination of DAMPs in the form of total cell/skeletal muscle tissue lysates. Our data demonstrated that multiple DAMPs, including HMGB1, HSPs, histone H3, SAA, and oxPAPC, as well as cell/tissue lysate preparations, induced substantially higher (~7–10-fold) IL-8 cytokine responses in HEK293 cells overexpressing CD36 compared to control WT cells. At the same time, DAMP-induced secretion of IL-6 in bone marrow-derived macrophages (BMDM) from CD36−/− mice was markedly (~2–3 times) reduced, as compared to macrophages from normal mice. Synthetic amphipathic helical peptides (SAHPs), known CD36 ligands, efficiently blocked CD36-dependent inflammatory responses induced by both cell and tissue lysates, HMGB1 and histone H3 in CD36+ cells. IP injection of total cellular lysate preparation induced inflammatory responses that were assessed by the expression of liver and lung pro-inflammatory markers, including IL-6, TNF-α, CD68, and CXCL1, and was reduced by ~50% in CD36-deficient mice compared to normal mice. Our findings demonstrate that CD36 is a PRR contributing to the innate immune response via mediating DAMP-induced inflammatory signaling and highlight the importance of this receptor as a potential therapeutic target in DAMP-associated inflammatory conditions. Full article

Visfatin, an adipokine secreted by various cell types, plays multifaceted pathophysiological roles in inflammatory conditions, including obesity, which is closely associated with osteoclastogenesis, a key process underlying bone loss and increased osteoporosis (OP) risk. However, the role of visfatin in osteoclastogenesis remains controversial. This study was conducted to investigate the effects of visfatin on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast differentiation from precursor cells in vitro. Our results demonstrated that although visfatin exhibited a modest osteoclast-inductive effect relative to that of RANKL, co-stimulation of bone marrow-derived macrophages (BMDMs) with visfatin and RANKL led to significantly enhanced osteoclast differentiation and activation compared to individual stimulation. Neutralization of visfatin activity using blocking antibodies before differentiation markedly suppressed RANKL-induced osteoclastogenesis, as evidenced by a near-complete absence of tartrate-resistant acid phosphatase-positive multinucleated osteoclasts, decreased levels of nuclear factor of activated T cells cytoplasmic 1 and osteoclast-specific proteins, inhibition of nuclear factor-κB and mitogen-activated protein kinase signaling pathways, and a decrease in resorption pit formation. Our findings underscore the critical role of visfatin in RANKL-induced osteoclastogenesis in vitro and highlight the RANKL/visfatin signaling axis as a potential therapeutic target for destructive bone loss-related diseases. Full article