Search Results (233)

Osteoarthritis (OA) is the most prevalent form of joint arthritis, frequently associated with aging, mechanical wear, and inflammation. Our previous work demonstrated that cathelicidin-related antimicrobial peptide (Cramp) is upregulated in mouse OA cartilage, and that transient knockdown (KD) of Cramp in cultured chondrocytes decreases IL-1β-induced expression of matrix-degrading enzymes. The aim of this study was to determine the in vivo role of Cramp in OA pathogenesis using whole-body Cramp knockout (KO) mice. Normal skeletal development and growth plate morphology were assessed in E18.5d embryos and 2-week-old mice, respectively. Expression profiles of catabolic and anabolic genes were analyzed in primary chondrocytes derived from Cramp KO mice. OA in mouse knee joints was induced using intra-articular monosodium iodoacetate (MIA) injections or surgical destabilization of the medial meniscus (DMM). We observed that Cramp loss does not impact normal skeletal development. In contrast to our expectations, complete Cramp deficiency in chondrocytes failed to decrease catabolic gene expression upon IL-1β stimulation. Instead, genetic deletion of Cramp significantly worsened OA cartilage degradation in both MIA- and DMM-induced models. The detrimental phenotype observed in Cramp-deficient mice results from enhanced chondrocyte apoptosis. Therefore, even minimal Cramp expression appears essential for maintaining catabolic balance and preventing chondrocyte apoptosis in OA cartilage. Collectively, our data indicate that Cramp may exert multifaceted effects on OA pathogenesis by modulating catabolic pathways and apoptosis. Full article

Neuroinflammation is the major contributor to the pathology of neonatal hypoxic–ischemic (HI) brain injury. Our previous studies have demonstrated that microRNA210 (miR210) inhibition with antisense locked nucleic acid (LNA) inhibitor mitigates neuroinflammation and provides neuroprotection after neonatal HI insult. However, the underlying mechanisms remain elusive. In the present study, using miR210 knockout (KO) mice and microglial cultures, we tested the hypothesis that miR210 promotes microglial activation and neuroinflammation through suppressing mitochondrial function in microglia after HI. Neonatal HI brain injury was conducted on postnatal day 9 (P9) wild-type (WT) and miR210 knockout (KO) mouse pups. We found that miR210 KO significantly reduced brain infarct size at 48 h and improved long-term locomotor functions assessed by an open field test three weeks after HI. Moreover, miR210 KO mice exhibited reduced IL1β levels, microglia activation and immune cell infiltration after HI. In addition, in vitro studies of microglia exposed to oxygen–glucose deprivation (OGD) revealed that miR210 inhibition with LNA reduced OGD-induced expression of Il1b and rescued OGD-mediated downregulation of mitochondrial iron–sulfur cluster assembly enzyme (ISCU) and mitochondrial oxidative phosphorylation activity. To validate the link between miR210 and microglia activation, isolated primary murine microglia were transfected with miR210 mimic or negative control. The results showed that miR210 mimic downregulated the expression of mitochondrial ISCU protein abundance and induced the expression of proinflammatory cytokines similar to the effect observed with ISCU silencing RNA. In summary, our results suggest that miR210 is a key regulator of microglial proinflammatory activation through reprogramming mitochondrial function in neonatal HI brain injury. Full article

Background: As a well-known environmental hazard, ambient fine particulate matter (PM_2.5, aerodynamic diameter ≤ 2.5 µm) has been positively correlated with an increased risk of digestive system diseases, including appendicitis, inflammatory bowel disease, and gastrointestinal cancer. Additionally, PM_2.5 exposure has been shown to alter microbiota composition and diversity in human and animal models. However, its impact on goblet cells and gut mucus barrier integrity remains unclear. Methods: To address this, 8-week-old male and female interleukin-10 knockout (IL10^−/−) mice, serving as a spontaneous colitis model, were exposed to concentrated ambient PM_2.5 or filtered air (FA) in a whole-body exposure system for 17 weeks. Colon tissues from the PM_2.5-exposed mice and LS174T goblet cells were analyzed using H&E staining, transmission electron microscopy (TEM), and transcriptomic profiling. Results: The average PM_2.5 concentration in the exposure chamber was 100.20 ± 13.79 µg/m³. PM_2.5 exposure in the IL10^−/− mice led to pronounced colon shortening, increased inflammatory infiltration, ragged villi brush borders, dense goblet cells with sparse enterocytes, and lipid droplet accumulation in mitochondria. Similar ultrastructure changes were exhibited in the LS174T goblet cells after PM_2.5 exposure. Transcriptomic analysis revealed a predominantly upregulated gene expression spectrum, indicating an overall enhancement rather than suppression of metabolic activity after PM_2.5 exposure. Integrated enrichment analyses, including GO, KEGG, and GSEA, showed enrichment in pathways related to oxidative stress, xenobiotic (exogenous compound) metabolism, and energy metabolism. METAFlux, a metabolic activity analysis, further substantiated that PM_2.5 exposure induces a shift in cellular energy metabolism preference and disrupts redox homeostasis. Conclusions: The findings of exacerbated gut barrier impairment and goblet cell dysfunction following PM_2.5 exposure provide new evidence of environmental factors contributing to colitis, highlighting new perspectives on its role in the pathogenesis of colitis. Full article

Background/Objectives: Ulcerative colitis (UC) is characterized by the interplay between immune responses and dysbiosis in disease development. Aiming to provide additional insights into disease development and potential treatment strategies, the present study investigates the local effect of oral treatment with polysaccharides obtained from Auricularia auricula’s submerged culture in an experimental model of DSS-induced colitis and its impact on lesion resolution. Methods: The structure and monosaccharide composition of Auricularia polysaccharides were characterized through Nuclear Magnetic Resonance (NMR). To evaluate the effect of this polysaccharide on the murine model, wild-type and Dectin-1 knockout mice were treated or not with the exopolysaccharide (EPS) while under DSS consumption. During the experimental period, feces samples were collected to evaluate microbial shifts during disease development, and, finally, the colonic tissue was analyzed to assess the inflammatory process and cytokine production. Results: The EPS composition showed a polymeric mixture of glucans and fucogalactomannans. The treatment of the wild-type DSS-induced colitis group improved the inflammatory response by increasing gut–homeostatic cytokines, such as interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α). The Dectin-1 KO mice group did not show the same enhancement after EPS treatment. The microbiome analysis revealed a difference in the genotype, and the treatment modified the DSS microbiome modulation, with nine and four ASVs in WT and Dectin-1 KO mice, respectively. Conclusions: The EPS treatment demonstrated therapeutic potential in treating inflammatory intestinal diseases by modulating cytokine secretion and microbiota composition, which is dependent on the Dectin-1 receptor’s carbohydrate recognition. Full article

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by bile duct inflammation and fibrosis, leading to cirrhosis and liver failure. Current therapies are limited to symptom management, with no approved treatments targeting fibrosis. We have identified the MAP kinase-activated protein kinase 2 (MK2) pathway as a potential therapeutic target for treating PSC due to its role in promoting inflammatory cytokine production and activation of fibroblasts. Thus, MDR2 knockout mice were treated therapeutically with MK2 inhibitors, which led to significantly reduced hepatic inflammation and fibrosis. Liver enzymes, collagen 1A1, and fibronectin were decreased in serum with MK2 inhibitor treatment. Furthermore, the production of IL-6, TNFα, CXCL5, collagen 1A1, and fibronectin was decreased in liver tissues and liver stellate cells, whereas the production of IL-10, G-CSF, and IL-22 was increased. MDR2KO mice treated with IL-22 also showed improvements in inflammation and fibrosis, along with increased IL-10 and G-CSF production. Taken together, we identified both a direct mechanism of MK2 regulation of fibrotic factors and an indirect cytokine-mediated mechanism whereby the levels of IL-22, IL-10, and G-CSF were increased with MK2 inhibition and contributed to decreased levels of fibrotic factors. These data suggest that the MK2 pathway is a promising treatment target for PSC. Full article

Background/Objectives: 5-Aminolevulinic acid (5-ALA) is a biosynthetic precursor of heme that induces heme oxygenase-1 (HO-1). Therapeutic induction of HO-1 has shown effectiveness in various autoimmune disease models, including type 1 diabetes (T1D). However, the efficacy of 5-ALA as an HO-1 inducer in T1D models remains unexplored. This study aimed to investigate the therapeutic efficacy of oral 5-ALA administration in preventing autoimmune diabetes development in nonobese diabetic (NOD) mice. Methods: We evaluated diabetes incidence, levels of insulin autoantibody, and severity of insulitis in 5-ALA-treated and control NOD mice. HO-1 expression of dendritic cells in the pancreatic islets and spleen of 5-ALA-treated NOD mice was measured. The IFN-γ/IL-17 of islet-infiltrating T cells and IL-10/IL-12 productions of dendritic cells in the spleen of 5-ALA-treated NOD mice were assessed. We stimulated islet antigen-specific CD4⁺ T cells with islet antigen-pulsed dendritic cells in the presence of 5-ALA and examined the proliferation of the T cells. Finally, we adoptively transferred islet antigen-specific CD4⁺ T cells into 5-ALA-treated, immunodeficient NOD-Rag1 knockout mice, and diabetes incidence in recipients was determined. Results: Oral 5-ALA treatment did not significantly impact diabetes incidence, levels of insulin autoantibody, and insulitis. No significant difference was observed in HO-1 expression in dendritic cells and cytokine production of T cells and dendritic cells. Similarly, there was no significant difference in the proliferation of islet antigen-specific CD4⁺ T cells in vitro and diabetes induction in transfer experiments. Conclusions: Oral administration of 5-ALA has a limited effect on suppressing the development of autoimmune diabetes in NOD mice. Full article

Background/Objectives: Non-melanoma skin cancer (NMSC) is among the most common cancers in the United States, with solar ultraviolet (UV) radiation being a primary etiological factor. T-LAK cell-originated protein kinase (TOPK), a serine/threonine kinase activated by solar UV, has been implicated in skin carcinogenesis. This study aimed to investigate the mechanistic role of TOPK in solar UV-induced skin damage and tumor development. Methods: RNA sequencing (RNA-seq) was performed on skin tissues from wild-type (WT) and TOPK knockout (KO) mice, with or without solar UV exposure, to identify TOPK-regulated genes and pathways. Follow-up experiments using Western blotting, immunofluorescence, and luciferase assays were conducted in vitro and in vivo. Functional assays included 3D spheroid and Transwell co-culture systems involving cutaneous squamous cell carcinoma (cSCC) and fibroblast cells. Results: TOPK deletion altered gene expression profiles and inhibited solar UV-induced activation of multiple signaling pathways, including cytokine–cytokine receptor interaction, PI3K/AKT, MAPKs, PKG, cAMP, and calcium signaling. RNA-seq and protein analyses identified interleukin-19 (IL19) as a key downstream effector suppressed by TOPK deletion. In cSCC and fibroblast cells, TOPK knockdown reduced IL19 expression and secretion. IL19 promoted cSCC growth and activated PI3K/AKT, ERK, and TOPK pathways. Additionally, chronic TGFβ exposure increased IL19 expression and activated fibroblasts, as indicated by elevated αSMA and FAPα levels. Conclusions: These findings establish TOPK as a central regulator of solar UV-induced skin carcinogenesis, partially via modulation of IL19 signaling and fibroblast activation. Targeting TOPK may offer a novel strategy for the prevention and treatment of NMSC. 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

The interaction between immune regulatory cells, such as regulatory B cells (Breg) and pro-resolving macrophages (M2 macrophages), plays an important role in the restoration of immune homeostasis during inflammation. PD-L1 is one of the effector molecules that mediates the immune regulation function of M2 macrophages. The activation of PD-L1/PD-1 signaling promotes the differentiation of Breg. Previous studies have shown that Breg promoted M2 macrophage polarization and enhanced their function, but little is known about the regulatory function of M2 macrophages on Breg differentiation. This study aims to determine the effect of M2 macrophages on Breg induction and the potential mechanism in vitro. Bone-marrow-derived macrophages were isolated from wild-type (WT) mice and polarized into M2 using IL-4/IL-13. To investigate the role of PD-L1/PD-1 in M2 macrophage-induced Breg differentiation, spleen B cells were isolated from WT or PD-1 knockout (KO) mice and co-cultured with either naïve (M0) or M2 macrophages for 48 h with or without trans-well inserts. The expression of IL-10, IL-35, and TGF-β1 in B cells was evaluated by flow cytometry and immunofluorescence staining. Recombinant PD-L1 was used to stimulate activated B cells, followed by the detection of IL-35 and TGF-β1. The results show that there was no significant difference in IL-10 expression among all groups. However, IL-35 and TGF-β1 expression in B cells was significantly increased in the M2+B, but not in M0+B, compared to B cells alone. Notably, such increases were diminished when M2 and B cells were separated by trans-well inserts. IL-35 expression was not significantly changed when B cells from PD-1 KO mice were co-cultured with M2 compared to the control. However, TGF-β1 expression was significantly increased when PD-1 KO B cells were co-cultured with M2 compared to the control. IL-35 expression in activated B cells was increased upon stimulation with PD-L1. However, TGF-β1 expression in activated B cells was increased regardless of the PD-L1 availability. This study demonstrates that pro-resolving macrophage-induced IL-35⁺ but not TGF-β1⁺ regulatory B cell activation requires the PD-L1/PD-1 pathway. Full article

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that survives and replicates within host cells. Macrophages, key immune cells in infection defense, play a vital role in pathogen clearance through polarization (M1/M2) and NLRP3 inflammasome activation. While TRIM67 regulates macrophage recruitment in the liver, its role in S. Typhimurium infection remains unclear. In this study, a S. Typhimurium infection model was established by orally infecting streptomycin-pretreated TRIM67 WT and KO mice with 1 × 10⁹ CFU of S. Typhimurium. TRIM67 expression in the ileum, colon, mesenteric lymph nodes (MLNs), and peritoneal macrophages (PMs) was assessed via qRT-PCR and Western blotting. Histopathological changes were analyzed using HE and PAS staining. IHC staining, flow cytometry (FCM), qRT-PCR, and Western blotting were used to evaluate TRIM67 knockout effects on macrophage recruitment, polarization, and NLRP3 inflammasome activation. In vitro, PMs were infected with S. Typhimurium (MOI 1:20), and TRIM67’s role in macrophage polarization and NLRP3 activation was validated. S. Typhimurium infection significantly upregulated TRIM67 in the ileum, colon, and MLN. TRIM67 knockout reduced intestinal inflammatory cell infiltration but worsened goblet cell loss and impaired digestion. Bacterial load assays revealed weakened pathogen clearance, leading to weight loss and increased mortality. TRIM67 knockout inhibited intestinal macrophage recruitment, M1 polarization in MLN, and NLRP3 activation. In vitro, TRIM67 knockout increased PMs’ intracellular bacterial load and suppressed NLRP3, caspase-1, and IL-1β expression. TRIM67 knockout impairs the host’s ability to clear S. Typhimurium by inhibiting M1 macrophage polarization and NLRP3 inflammasome activation. 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

In eutherian mammals, embryo implantation is a critical process for a successful pregnancy. In mice, the activation of the leukemia inhibitory factor (LIF) receptor–STAT3 signaling axis induces embryo adhesion and decidualization. The LIF receptor is believed to function as a heterodimer composed of LIFR (encoded by Lifr) and GP130 (encoded by Il6st); however, their distinct expression patterns in the uterine epithelium immediately prior to implantation suggest divergent functional roles. In this study, we generated uterine epithelium-specific Lifr knockout (Lifr eKO) mice and conducted a comprehensive gene expression analysis of the endometrium before implantation. We compared these results with those from uterine epithelium-specific Gp130 knockout (Gp130 eKO) mice. Similarly to Gp130 eKO mice, Lifr eKO mice were completely infertile. We identified 299 genes with expression changes greater than twofold following gene deletion; among these, 31 genes were downregulated and 57 genes were upregulated in both eKO models. Many of the downregulated genes were previously implicated in uterine function. Hub gene analysis identified Erbb2 and c-Fos as key regulators in both models. Further experiments using an ERBB2 inhibitor suggested that LIFR–ERBB2-mediated signaling plays a crucial role in embryo implantation. Full article

Ischemic stroke is a leading cause of death and disability worldwide. Currently, there is an unmet clinical need for pharmacological treatments that can improve ischemic stroke outcomes. In this study, we investigated the role of brain peroxisome proliferator-activated receptor alpha (PPARα) in ischemic stroke pathophysiology. We used a well-established model of cerebral ischemia in PPARα transgenic mice and conducted the RNA sequencing (RNA-seq) of mouse stroke brains harvested 48 h post-middle cerebral artery occlusion (MCAO). PPARα knockout (KO) increased brain infarct size following stroke, indicating a protective role of PPARα in brain ischemia. Our RNA-seq analysis showed that PPARα KO altered the expression of genes in mouse brains with known roles in ischemic stroke pathophysiology. We also identified many other differentially expressed genes (DEGs) upon the loss of PPARα that correlated with increased infarct size in our stroke model. Gene set enrichment analysis (GSEA) and Gene Ontology (GO) analysis revealed the upregulation of gene signatures for the positive regulation of leukocyte proliferation, apoptotic processes, acute-phase response, and cellular component disassembly in mouse stroke brains with PPARα KO. In addition, pathway analysis of our RNA-seq data revealed that TNFα signaling, IL6/STAT3 signaling, and epithelial–mesenchymal transition (EMT) gene signatures were increased in PPARα KO stroke brains. Our study highlights PPARα as an attractive drug target for ischemic stroke due to its transcriptional regulation of inflammation-, apoptosis-, and EMT-related genes in brain tissue following ischemia. Full article

Crohn’s disease is an inflammatory bowel disease (IBD) that currently lacks satisfactory treatment options. Therefore, new targets for new drugs are urgently needed to combat this disease. In the present study, we investigated the transcriptomics-based mRNA expression of intestinal biopsies from patients with Crohn’s disease. We compared the mRNA expression profiles of the ileum and colon of patients with those of healthy individuals. A total of 72 genes in the ileum and 33 genes in the colon were differentially regulated. Among these, six genes were overexpressed in both tissues, including IL1B, TCL1A, HCAR3, IGHG1, S100AB, and OSM. We further focused on OSM/oncostatin M. To confirm the responsiveness of intestinal tissues from patients with Crohn’s disease to oncostatin M inhibition, we examined the expression of the oncostatin M using immunohistochemistry in patient biopsies as well as in kindlin-1^−/− and kindlin-2^−/− knockout mice, which exhibit an inflammatory bowel disease (IBD) phenotype, and found strong oncostatin M expression in all samples examined. Next, we conducted a drug-repurposing study using the supercomputer MOGON and bioinformatic methods. A total of 13 candidate compounds out of 1577 FDA-approved drugs were identified by PyRx-based virtual drug screening and AutoDock-based molecular docking. Their lowest binding energies (LBEs) ranged from −10.46 (±0.08) to −8.77 (±0.08) kcal/mol, and their predicted inhibition constants (pK_i) ranged from 21.62 (±2.97) to 373.78 (±36.78) nM. Ecamsule has an interesting stereostructure with two C₂-symmetric enantiomers (1S,4R-1′S,4′R and 1R,4S-1′R,4′S) (1a and 1b) and one meso diastereomer (1S,4R-1′R,4′S) (1c). These three stereoisomers showed strong, albeit differing, binding affinities in molecular docking. As examined by nuclear magnetic resonance and polarimetry, the 1S,4R-1′S,4′R isomer was the stereoisomer present in our commercially available preparations used for microscale thermophoresis. Ecamsule (1a) was chosen for in vitro validation using recombinant oncostatin M and microscale thermophoresis. Considerable dissociation constants were obtained for ecamsule after three repetitions with a K_d value of 11.36 ± 2.83 µM. Subsequently, we evaluated, by qRT-PCR, the efficacy of ecamsule (1a) as a potential drug that could prevent oncostatin M activation by inhibiting downstream inflammatory marker genes (IL6, TNFA, and CXCL11). In conclusion, we have identified oncostatin M as a promising new drug target for Crohn’s disease through transcriptomics and ecamsule as a potential new drug candidate for Crohn’s disease through a drug-repurposing approach both in silico and in vitro. Full article