The exoprotein Gbp of Fusobacterium nucleatum promotes THP-1 cell lipid deposition by binding to CypA and activating PI3K-AKT/MAPK/NF-κB pathways.

INTRODUCTION: Growing evidence has shown the correlation between periodontitis and atherosclerosis, while our knowledge on the pathogenesis of periodontitis-promoting atherosclerosis is far from sufficient. OBJECTIVES: Illuminate the pathogenic effects of Fusobacterium nucleatum (F. nucleatum) on intracellular lipid deposition in THP-1-derived macrophages and elucidate the underlying pathogenic mechanism of how F. nucleatum promoting atherosclerosis. METHODS AND RESULTS: F. nucleatum was frequently detected in different kinds of atherosclerotic plaques and its abundance was positively correlated with the proportion of macrophages. In vitro assays showed F. nucleatum could adhere to and invade THP-1 cells, and survive continuously in macrophages for 24 h. F. nucleatum stimulation alone could significantly promote cellular inflammation, lipid uptake and inhibit lipid outflow. The dynamic gene expression of THP-1 cells demonstrated that F. nucleatum could time-serially induce the over-expression of multiple inflammatory related genes and activate NF-κB, MAPK and PI3K-AKT signaling pathways. The exoprotein of F. nucleatum, D-galactose-binding protein (Gbp), acted as one of the main pathogenic proteins to interact with the Cyclophilin A (CypA) of THP-1 cells and induced the activation of the NF- κB, MAPK and PI3K-AKT signaling pathways. Furthermore, use of six candidate drugs targeting to the key proteins in NF- κB, MAPK and PI3K-AKT pathways could dramatically decrease F. nucleatum induced inflammation and lipid deposition in THP-1 cells. CONCLUSIONS: This study suggests that the periodontal pathogen F. nucleatum can activate macrophage PI3K-AKT/MAPK/NF-κB signal pathways, promotes inflammation, enhances cholesterol uptake, reduces lipid excretion, and promotes lipid deposition, which may be one of its main strategies promoting the development of atherosclerosis.

Pangenomic Study of Fusobacterium nucleatum Reveals the Distribution of Pathogenic Genes and Functional Clusters at the Subspecies and Strain Levels.

Fusobacterium nucleatum is a prevalent periodontal pathogen and is associated with many systemic diseases. Our knowledge of the genomic characteristics and pathogenic effectors of different F. nucleatum strains is limited. In this study, we completed the whole genome assembly of the 4 F. nucleatum strains and carried out a comprehensive pangenomic study of 30 strains with their complete genome sequences. Phylogenetic analysis revealed that the F. nucleatum strains are mainly divided into 4 subspecies, while 1 of the sequenced strains was classified into a new subspecies. Gene composition analysis revealed that a total of 517 "core/soft-core genes" with housekeeping functions widely distributed in almost all the strains. Each subspecies had a unique gene cluster shared by strains within the subspecies. Analysis of the virulence factors revealed that many virulence factors were widely distributed across all the strains, with some present in multiple copies. Some virulence genes showed no consistent occurrence rule at the subspecies level and were specifically distributed in certain strains. The genomic islands mainly revealed strain-specific characteristics instead of subspecies level consistency, while CRISPR types and secondary metabolite biosynthetic gene clusters were identically distributed in F. nucleatum strains from the same subspecies. The variation in amino acid sites in the adhesion protein FadA did not affect the monomer and dimer 3D structures, but it may affect the binding surface and the stability of binding to host receptors. This study provides a basis for the pathogenic study of F. nucleatum at the subspecies and strain levels. IMPORTANCE We used F. nucleatum as an example to analyze the genomic characteristics of oral pathogens at the species, subspecies, and strain levels and elucidate the similarities and differences in functional genes and virulence factors among different subspecies/strains of the same oral pathogen. We believe that the unique biological characteristics of each subspecies/strain can be attributed to the differences in functional gene clusters or the presence/absence of certain virulence genes. This study showed that F. nucleatum strains from the same subspecies had similar functional gene compositions, CRISPR types, and secondary metabolite biosynthetic gene clusters, while pathogenic genes, such as virulence genes, antibiotic resistance genes, and GIs, had more strain level specificity. The findings of this study suggest that, for microbial pathogenicity studies, we should carefully consider the subspecies/strains being used, as different strains may vary greatly.

Selective Inhibition of 11ß-Hydroxysteroid Dehydrogenase Type 1 Attenuates High-Fat Diet-Induced Hepatic Steatosis in Mice.

INTRODUCTION: The effect of 11ß-hydroxysteroid dehydrogenase type1 (11ß-HSD1) inhibition on hepatic steatosis is incompletely understood. Here, we aimed to determine the therapeutic effect of BVT.2733, a selective 11ß-HSD1 inhibitor, on hepatic steatosis. MATERIALS AND METHODS: C57B/6J mice were randomly divided into a low-fat diet (LFD) fed group and a high-fat diet (HFD) fed group. Mice were fed with HFD for 28 weeks which induced obesity and severe hepatic steatosis. The two groups were further divided into four groups as follows: LFD, LFD with BVT.2733, HFD, and HFD with BVT.2733. Mice in LFD+BVT and HFD+BVT groups were intraperitoneally injected with BVT.2733 daily for 30 days. Effects of BVT.2733 on mice body weight, serum lipid profile, serum free fatty acids (FFAs), glucocorticoid levels, gene expression in adipose and liver tissues were assessed. RESULTS: Injection of a low dose of BVT.2733 (50 mg/kg/day) reduced body weight and hyperlipidemia, but did not improve glucose tolerance and insulin resistance in diet-induced obese mice. The low dose of BVT.2733 attenuated hepatic steatosis, liver injury, and liver lipolytic gene expression in diet-induced obese mice. Besides, the low dose of BVT.2733 reduced fat mass and lipolysis in visceral adipose tissues, hepatic FFAs, and serum corticosterone levels in diet-induced obese mice. CONCLUSION: Our study shows that moderate inhibition of 11ß-HSD1 by BVT.2733 reduces FFAs and corticosterone synthesis in fatty tissues, thereby attenuates the delivery of corticosterone and FFAs to the liver. Collectively, this prevents high-fat diet-induced hepatic steatosis.

Comparison of efficacy between natural orifice specimen extraction without abdominal incision and conventional laparoscopic surgery in the treatment of sigmoid colon cancer and upper rectal cancer.

PURPOSE: To compare the short-term efficacy between natural orifice specimen extraction (NOSE) without abdominal incision and conventional laparoscopic surgery in the treatment of sigmoid colon cancer and upper rectal cancer. METHODS: A total of 86 patients scheduled to undergo laparoscope-assisted radical surgery of sigmoid cancer or upper rectal cancer from January 2015 to September 2017 (T1-3 stages in preoperative imaging evaluation, no distant metastasis, and body mass index <28 kg/m2) were selected and randomly divided into the NOSE group (no abdominal incision, n=43) and conventional laparoscopy group (LA group, n=43). The operation time, amount of intraoperative bleeding, postoperative exhaust time, postoperative diet time, postoperative hospitalization duration, postoperative pain score and perioperative complications were compared between the two groups. The pathological conditions of surgical specimens were recorded. The postoperative recurrence rate of tumor and survival rate of patients were also recorded and compared. RESULTS: The general clinical features were comparable between the two groups, and there were no perioperative deaths. The operation time in NOSE group was slightly longer than that in LA group, without statistically significant difference (p=0.130). In NOSE group, the amount of intraoperative bleeding was significantly smaller than in LA group [(59.31±14.64) mL vs. (75.41±18.16) mL, p<0.001], the postoperative visual analogue scale (VAS) score was significantly lower than that in LA group [(4.2±1.6) points vs. (5.9±1.4) points, p<0.001], and the postoperative exhaust time and regular diet time were significantly shorter than those in LA group [(2.1±1.0) d vs. (2.6±1.2) d, p=0.039, (3.8±1.1) d vs. (4.4±1.4) d, p=0.030]. The cosmetic result in NOSE group was better than that in LA group [(8.0±1.5) vs. (6.4±1.1), p<0.001]. Moreover, the comparison results of surgical specimens showed that there were no statistically significant differences in the intestine resection length, proximal and distal resection margins, tumor size, number of lymph nodes dissected and TNM stage of tumor between the two groups (p>0.05). The postoperative tumor recurrence rate had no significant difference between the two groups (p=0.359), and the Log-rank test revealed that the disease-free survival (DFS) rate had no statistically significant difference between the two groups (p=0.280). CONCLUSIONS: NOSE without abdominal incision has a comparable short-term clinical efficacy to conventional laparoscopic surgery in the treatment of sigmoid cancer and upper rectal cancer, but it significantly reduces the amount of intraoperative bleeding and lowers the pain of patients, with rapid postoperative recovery and high safety, so it is worthy of clinical popularization.