Cancer stem cells (CSCs) are widely acknowledged as primary mediators to the initiation and progression of tumors. The association between microbial infection and cancer stemness has garnered considerable scholarly interest in recent years. Porphyromonas gingivalis (P. gingivalis) is increasingly considered to be closely related to the development of oral squamous cell carcinoma (OSCC). Nevertheless, the role of P. gingivalis in the stemness of OSCC cells remains uncertain. Herein, we showed that P. gingivalis was positively correlated with CSC markers expression in human OSCC specimens, promoted the stemness and tumorigenicity of OSCC cells, and enhanced tumor formation in nude mice. Mechanistically, P. gingivalis increased lipid synthesis in OSCC cells by upregulating the expression of stearoyl-CoA desaturase 1 (SCD1) expression, a key enzyme involved in lipid metabolism, which ultimately resulted in enhanced acquisition of stemness. Moreover, SCD1 suppression attenuated P. gingivalis-induced stemness of OSCC cells, including CSCs markers expression, sphere formation ability, chemoresistance, and tumor growth, in OSCC cells both in vitro and in vivo. Additionally, upregulation of SCD1 in P. gingivalis-infected OSCC cells was associated with the expression of KLF5, and that was modulated by P. gingivalis-activated NOD1 signaling. Taken together, these findings highlight the importance of SCD1-dependent lipid synthesis in P. gingivalis-induced stemness acquisition in OSCC cells, suggest that the NOD1/KLF5 axis may play a key role in regulating SCD1 expression and provide a molecular basis for targeting SCD1 as a new option for attenuating OSCC cells stemness.
Porphyromonas gingivalis/pathogenicity* ; Stearoyl-CoA Desaturase/metabolism* ; Humans ; Carcinoma, Squamous Cell/pathology* ; Mouth Neoplasms/metabolism* ; Animals ; Neoplastic Stem Cells/microbiology* ; Mice, Nude ; Mice ; Nod1 Signaling Adaptor Protein/metabolism* ; Kruppel-Like Transcription Factors/metabolism* ; Cell Line, Tumor

Aging involves the accumulation of various forms of molecular and cellular damage over time. Key features of aging, such as mitochondrial dysfunction, dysbiosis, and oxidative stress, are closely linked and largely driven by inflammation. This study examines the role of succinate, a key metabolite produced and utilized by cells of both host and microbes, and its receptor, succinate receptor 1 (SUCNR1), in age-related oral dysbiosis and inflammation. We examined young and aged wild-type (WT) and SUCNR1 knockout (KO) mice for this analysis. Our findings revealed significant aging-associated alveolar bone loss and succinate elevation in aged WT mice, along with notable changes in the oral microbiome. Conversely, aged KO mice showed reduced bone loss, lower succinate levels, less inflammation, and better-maintained microbial function. These results suggest that SUCNR1 is crucial in influencing aging-related succinate elevation, oral dysbiosis, and inflammation. Analysis of gene families and pathways in the oral microbiome demonstrated distinct aging-related changes between WT and KO mice, with the functional potential being preserved in the KO-aged group. This study underscores the importance of succinate elevation and signaling through SUCNR1 in regulating inflammation, alveolar bone loss, and shifts in the oral microbiome, offering potential targets for therapeutic interventions in age-related oral health issues.
Animals ; Dysbiosis/metabolism* ; Mice ; Succinic Acid/metabolism* ; Mice, Knockout ; Receptors, G-Protein-Coupled/metabolism* ; Inflammation/metabolism* ; Aging ; Alveolar Bone Loss/metabolism* ; Mouth/microbiology* ; Mice, Inbred C57BL ; Male ; Microbiota

This study investigates the role of Interleukin 17 (IL-17) in exacerbating periapical lesions caused by Porphyromonas gingivalis (Pg) lipopolysaccharides (LPS) in the context of metabolic disease and its potential impact on glucose tolerance. Researchers developed a unique mouse model where mice were monocolonized with Pg to induce periapical lesions. After 1 month, they were fed a high-fat diet (HFD) for 2 months to simulate metabolic disease and oral microbiota dysbiosis. To explore the role of LPS from Pg, wild-type (WT) mice were challenged with purified LPS from Porphyromonas gingivalis, as well as with LPS-depleted and non-depleted Pg bacteria; IL-17 knockout (KO) mice were also included to assess the role of IL-17 signaling. The impact on bone lysis, periapical injury, glucose intolerance, and immune response was assessed. Results showed that in WT mice, the presence of LPS significantly worsened bone lysis, Th17 cell recruitment, and periapical injury. IL-17 KO mice exhibited reduced bone loss, glucose intolerance, and immune cell infiltration. Additionally, inflammatory markers in adipose tissue were lower in IL-17 KO mice, despite increased dysbiosis. The findings suggest that IL-17 plays a critical role in amplifying Pg-induced periapical lesions and systemic metabolic disturbances. Targeting IL-17 recruitment could offer a novel approach to improving glycemic control and reducing type 2 diabetes (T2D) risk in individuals with periapical disease.
Animals ; Porphyromonas gingivalis/immunology* ; Th17 Cells/immunology* ; Lipopolysaccharides/immunology* ; Mice ; Glucose Intolerance/microbiology* ; Interleukin-17/metabolism* ; Mice, Knockout ; Mice, Inbred C57BL ; Disease Models, Animal ; Diet, High-Fat ; Periapical Diseases/microbiology* ; Male ; Dysbiosis

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder in which patients experience recurrent eczematous lesions and intense itching. The colonization of Staphylococcus aureus (S. aureus) is correlated with the severity of the disease, but its role in AD development remains elusive. Using single-cell RNA sequencing, we uncovered that keratinocytes activate a distinct immune response characterized by induction of Il24 when exposed to methicillin-resistant S. aureus (MRSA). Further experiments using animal models showed that the administration of recombinant IL-24 protein worsened AD-like pathology. Genetic ablation of Il24 or the receptor Il20rb in keratinocytes alleviated allergic inflammation and atopic march. Mechanistically, IL-24 acted through its heterodimeric receptors on keratinocytes and augmented the production of IL-33, which in turn aggravated type 2 immunity and AD-like skin conditions. Overall, these findings establish IL-24 as a critical factor for onset and progression of AD and a compelling therapeutic target.
Dermatitis, Atopic/genetics* ; Interleukins/metabolism* ; Animals ; Methicillin-Resistant Staphylococcus aureus/immunology* ; Mice ; Keratinocytes/microbiology* ; Humans ; Interleukin-33/immunology* ; Inflammation/microbiology* ; Staphylococcal Infections/microbiology* ; Disease Models, Animal ; Hypersensitivity/microbiology* ; Mice, Inbred C57BL

OBJECTIVE: To investigate the mechanism of autophagy in regulating bacterial translocation in intestinal infection caused by hypervirulent Klebsiella pneumonia (hvKp) and explore the method of reducing translocation infection of intestinal bacteria. METHODS: Fifty C57BL/6J mice were divided into gavage group (n = 40) and control group (CO group, n = 10). The gavage group was orally administered with 200 μL/d of hvKp (colony count of 10⁹ CFU/mL) continuously for 5 days to establish a hvKp intestinal infection model. CO group was given an equal amount of normal saline. After the experiment, the mice were anesthetized with lsofluraneand euthanized with cervical dislocation under anesthesia. Peripheral venous blood of mice was collected to detect bacterial translocation by 16S rDNA sequencing, then divided into translocation group (BT+ group) and non-translocation group (BT- group). Hematoxylin-eosin (HE) staining was used to evaluate intestinal morphology. The ultrastructural changes of intestinal tissues were observed by electron microscope. The levels of intestinal oxidative stress indicators such as superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GPx) were measured. Translocation was detected by in situ hybridization. The expression of tight junction protein microtubule-associated protein 1 light chain 3-II (LC3-II) and autophagy protein Beclin-1 were measured by Western blotting. The mRNA expression of tight junction proteins ZO-1 and Claudin-2 were detected by reverse transcription-polymerase chain reaction (RT-PCR). The expression of autophagy protein and tight junction protein were observed by immunofluorescence. RESULTS: Two out of 40 mice in the gavage group died after developing aspiration pneumonia. All mice in the CO group survived. The 16S rDNA sequencing results showed that no bacteria were detected in the peripheral blood of the CO group, but bacteria were detected in the peripheral blood of 18 mice in the gavage group, with a bacterial translocation rate of 47.4%. The BT- and BT+ groups showed intestinal mucosal tissue damage, with severe damage in the BT+ group. Compared with the CO group, the level of MDA in the BT- and BT+ groups were significantly increased, while the activities of SOD and GPx were significantly decreased. Compared with the BT- group, the MDA level in the BT+ group further increased, while the SOD and GPx activities further decreased [MDA (mmol/mg): 2.98±0.11 vs. 2.48±0.11, SOD (U/mg): 62.40±5.45 vs. 73.40±4.08, GPx (U/mg): 254.72±10.80 vs. 303.55±8.57, all P < 0.01]. The results of in situ hybridization detection showed that after continuous gastric lavage for 5 days, displaced hvKp was detected in the intestinal mucosal lamina propria and liver tissue of the BT+ group. Compared with the CO group, the protein expressions of LC3-II and Beclin-1 in the BT- and BT+ groups were significantly increased. The protein expressions of LC3-II and Beclin-1 in the BT+ group were obviously lower than those in the BT- group (LC3-II/β-actin: 0.38±0.04 vs. 0.70±0.09, Beclin-1/β-actin: 0.62±0.05 vs. 0.86±0.05, both P < 0.01), and there were autophagosomes in the intestinal mucosa. These results indicated that intestinal mucosal autophagy was activated after hvKp continuous gavage. Compared with CO group, the mRNA expressions of ZO-1 and Claudin-2 in the BT- and BT+ groups were significantly decreased. Compared with the BT- group, the mRNA expressions of ZO-1 and Claudin-2 in the BT+ group was further reduced [ZO-1 mRNA (2^-ΔΔCT): 0.78±0.06 vs. 0.88±0.06, Claudin-2 mRNA (2^-ΔΔCT): 0.40±0.04 vs. 0.70±0.06, both P < 0.01]. The immunofluorescence results showed that the fluorescence intensity of LC3-II, Beclin-1, ZO-1, and Claudin-2 in the BT+ group was significantly lower than that in the BT- group. CONCLUSION HvKp can activate intestinal mucosal autophagy and reduce the damage to intestinal mucosal barrier function by down-regulating oxidative stress level, reduce the occurrence of bacterial translocation.
Animals ; Oxidative Stress ; Mice, Inbred C57BL ; Autophagy ; Intestinal Mucosa/microbiology* ; Bacterial Translocation ; Mice ; Klebsiella Infections/microbiology* ; Superoxide Dismutase/metabolism* ; Beclin-1

Guided by molecular networking, nine novel curvularin derivatives (1-9) and 16 known analogs (10-25) were isolated from the hydrothermal vent sediment fungus Penicillium sp. HL-50. Notably, compounds 5-7 represented a hybrid of curvularin and purine. The structures and absolute configurations of compounds 1-9 were elucidated via nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction, electronic circular dichroism (ECD) calculations, ¹³C NMR calculation, modified Mosher's method, and chemical derivatization. Investigation of anti-inflammatory activities revealed that compounds 7-9, 11, 12, 14, 15, and 18 exhibited significant suppressive effects against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in murine macrophage RAW264.7 cells, with IC₅₀ values ranging from 0.44 to 4.40 μmol·L^-1. Furthermore, these bioactive compounds were found to suppress the expression of inflammation-related proteins, including inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), NLR family pyrin domain-containing protein 3 (NLRP3), and nuclear factor kappa-B (NF-κB). Additional studies demonstrated that the novel compound 7 possessed potent anti-inflammatory activity by inhibiting the transcription of inflammation-related genes, downregulating the expression of inflammation-related proteins, and inhibiting the release of inflammatory cytokines, indicating its potential application in the treatment of inflammatory diseases.
Penicillium/chemistry* ; Mice ; Animals ; Anti-Inflammatory Agents/isolation & purification* ; RAW 264.7 Cells ; Nitric Oxide/metabolism* ; Hydrothermal Vents/microbiology* ; Macrophages/immunology* ; Molecular Structure ; Nitric Oxide Synthase Type II/immunology* ; Cyclooxygenase 2/immunology* ; Geologic Sediments/microbiology* ; NF-kappa B/immunology* ; NLR Family, Pyrin Domain-Containing 3 Protein/immunology*

Given the increasing concern regarding antibacterial resistance, the antimicrobial properties of naphthoquinones have recently attracted significant attention. While 1,4-naphthoquinone and its derivatives have been extensively studied, the antibacterial properties of 5,8-dihydroxy-1,4-naphthoquinone derivatives remain relatively unexplored. This study presents a comprehensive in vitro and in vivo analysis of the antibacterial activity of 35 naturally sourced and chemically synthesized derivatives of 5,8-dihydroxy-1,4-naphthoquinone. Kirby-Bauer antibiotic testing identified three compounds with activity against methicillin-resistant Staphylococcus aureus (MRSA), with one compound (PNP-02) demonstrating activity comparable to vancomycin in minimum inhibitory concentration, minimum bactericidal concentration (MBC), and time-kill assays. Microscopic and biochemical analyses revealed that PNP-02 adversely affects the cell wall and cell membrane of MRSA. Mechanistic investigations, including proteomic sequencing analyses, Western blotting, and RT-qPCR assays, indicated that PNP-02 compromises cell membrane integrity by inhibiting arginine biosynthesis and pyrimidine metabolism pathways, thereby increasing membrane permeability and inducing bacterial death. In an in vivo mouse model of skin wound healing, PNP-02 exhibited antibacterial efficacy similar to vancomycin. The compound demonstrated low toxicity to cultured human cells and in hemolysis assays and remained stable during serum incubation. These findings suggest that PNP-02 possesses promising bioactivity against MRSA and represents a potential novel antibacterial agent.
Methicillin-Resistant Staphylococcus aureus/genetics* ; Anti-Bacterial Agents/chemistry* ; Naphthoquinones/administration & dosage* ; Animals ; Microbial Sensitivity Tests ; Mice ; Humans ; Staphylococcal Infections/microbiology* ; Molecular Structure

Salmonellosis represents a global epidemic, and the emergence of extensively drug-resistant (XDR) Salmonella and its sustained transmission worldwide constitutes a significant public health concern. Flagellum-mediated motility serves as a crucial virulence trait of Salmonella that guides the pathogen toward the epithelial surface, enhancing gut colonization. Artemisia argyit essential oil, a traditional herb extract, demonstrates efficacy in treating inflammation-related symptoms and diseases; however, its effects on flagellum assembly and expression mechanisms in anti-Salmonella activity remain inadequately explored. This study aimed to elucidate the mechanism by which Artemisia argyit essential oil addresses Salmonella infections. Network pharmacological analysis revealed that Traditional Chinese Medicine (TCM) Artemisia argyit exhibited anti-Salmonella infection potential and inhibited flagellum-dependent motility. The application of Artemisia argyit essential oil induced notable motility defects through the downregulation of flagellar and fimbriae expression. Moreover, it significantly reduced Salmonella-infected cell damage by interfering with flagellum-mediated Salmonella colonization. In vivo studies demonstrated that Artemisia argyit essential oil administration effectively alleviated Salmonella infection symptoms by reducing bacterial loads, inhibiting interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) production, and diminishing pathological injury. Gas chromatography-mass spectrometry (GC-MS) analysis identified forty-three compounds in Artemisia argyit essential oil, with their corresponding targets and active ingredients predicted. Investigation of an in vivo model of Salmonella infection using the active ingredient demonstrated that alpha-cedrene ameliorated Salmonella infection. These findings suggest the potential application of Artemisia argyit essential oil in controlling Salmonella, the predominant food-borne pathogen.
Artemisia/chemistry* ; Oils, Volatile/chemistry* ; Animals ; Flagella/drug effects* ; Salmonella Infections/microbiology* ; Humans ; Mice ; Anti-Bacterial Agents/pharmacology* ; Salmonella/pathogenicity*

OBJECTIVE: Pseudomonas aeruginosa( P. aeruginosa) is a prevalent pathogenic bacterium involved in meningitis; however, the virulence factors contributing to this disease remain poorly understood. METHODS: The virulence of the P. aeruginosa A584, isolated from meningitis samples, was evaluated by constructing in vitro blood-brain barrier and in vivo systemic infection models. qPCR, whole-genome sequencing, and drug efflux assays of A584 were performed to analyze the virulence factors. RESULTS: Genomic sequencing showed that A584 formed a phylogenetic cluster with the reference strains NY7610, DDRC3, Pa58, and Pa124. Its genome includes abundant virulence factors, such as hemolysin, the Type IV secretion system, and pyoverdine. A584 is a multidrug-resistant strain, and its wide-spectrum resistance is associated with enhanced drug efflux. Moreover, this strain caused significantly more severe damage to the blood-brain barrier than the standard strain, PAO1. qPCR assays further revealed the downregulation of the blood-brain barrier-associated proteins Claudin-5 and Occludin by A584. During systemic infection, A584 exhibited a higher capacity of brain colonization than PAO1 (37.1 × 10 ⁶ CFU/g brain versus 2.5 × 10 ⁶ CFU/g brain), leading to higher levels of the pro-inflammatory factors IL-1β and TNF-α. CONCLUSION This study sheds light on the virulence factors of P. aeruginosa involved in meningitis.
Pseudomonas aeruginosa/genetics* ; Virulence Factors/metabolism* ; Animals ; Virulence ; Mice ; Pseudomonas Infections/microbiology* ; Blood-Brain Barrier/microbiology* ; Humans ; Female

N-dodecanoyl-l-homoserine lactone (C12-HSL) is a signaling molecule that mediates bacterial quorum sensing, regulating bacterial population behaviors. This study investigated the effects of C12-HSL on the isolation and cultivation of gut microbiota, with the goal of enriching the diversity and number of cultivable bacterial strains from the mouse gut microbiota. Using a culture medium supplemented with C12-HSL, we isolated and cultivated bacterial strains from mouse intestinal contents, obtaining a total of 235 isolates. Preliminary identification based on the 16S rRNA gene revealed 54 bacterial species, including 4 potential new species, 4 potential new genera and 1 potential new family. Compared with the previously established mouse gut microbial biobank (mGMB), this study newly identified 42 bacterial species, enhancing the diversity of the strain library. Statistical analysis showed that the proportion of Gram-negative bacteria, particularly those belonging to Proteobacteria, isolated by this method was significantly higher than that obtained by conventional isolation and cultivation methods without the addition of C12-HSL. Subsequent cultivation experiments with one of the newly discovered bacterial species indicated that exogenous C12-HSL at 20-200 μmol/L significantly promoted the growth of this species, while higher concentrations of C12-HSL significantly reduced the cell density of this bacterium. This work confirms that quorum sensing molecules, such as C12-HSL, can enhance the growth, isolation, and cultivation of Gram-negative bacteria in the gut within a specific concentration range. Although the mechanism by which C12-HSL promotes the growth of gut bacterial strains requires further investigation, the findings of this study provide new insights into the targeted isolation, cultivation, and regulation of gut microbiota using bacterial quorum sensing signal molecules.
Animals ; Mice ; Acyl-Butyrolactones/pharmacology* ; Gastrointestinal Microbiome/drug effects* ; Quorum Sensing ; Gram-Negative Bacteria/classification* ; Intestines/microbiology* ; RNA, Ribosomal, 16S/genetics* ; Culture Media