Fig 2: Schematic diagram of the neuroprotective mechanism of wogonin after the occurrence of TBI. Wogonin increases the level of phosphorylated AKT and activates Nrf2, which translocates into the nucleus to increase HO-1 production. The high expression of HO-1 is responsible for anti-apoptosis and anti-oxidative stress, realizing the repair of TBI. TBI, traumatic brain injury; Nrf2, nuclear factor-erythroid factor 2-related factor 2; HO-1, heme oxygenase-1; Keap1, Kelch-like ECH-associated protein; ROS, reactive oxygen species.

Fig 3: DPG3 activated DC-SIGN, AKT, regulated FOXO1 phosphorylation/expression was required for the survival effect of DPG3 in MDDSCs. Immature monocytes isolated from human peripheral blood mononuclear cells (PBMCs) were infected with Pg381, DPG3 and MFI for 6 hours at 1 MOI. (A) Immunoblot analysis of DC-SIGN, p/tAKT, p/tFOXO1 and BIM in MDDSCs and MoDCs with GAPDH as loading control. Immunoblot detected increased expression of DC-SIGN, p/tAKT, p/tFOXO1 and decreased expression of BIM in DPG3- infected MDDSCs compared with uninfected control MoDCs. (B) DC-SIGN was blocked with HIV-gp120 (6ug/ml) for 30 minutes before infection. Notably, DC-SIGN expression and internalization was abolished by its antagonist HIV-gp120 and consequently the downstream signaling cascade also blocked as evident by dephosphorylated or decreased expression of pAKT (B,D), pFOXO1 (B,E) and increased expression of BIM (B,F). (C–F) Quantification analysis of DC-SIGN (C), and relative ratio of p/tAKT (D), p/tFOXO1 (E) and BIM (F) after normalized with the internal control GAPDH. Results are from one representative of three independent experiments. Data were analyzed by performing one-way ANOVA with Tukey’s post hoc using Prism GraphPad. *P = 0.05, **P = 0.01, ***P = 0.001.

Fig 4: FimA+Mfa1- Pg strain MFI stimulates proliferation of Human oral squamous carcinoma cells via CXCR4. (A) Pg-MFI (Mfa1-/FimA+) stimulates proliferation of human head and neck OSC cell lines HN6 and HN12, compared to uninfected cells or those incubated with E. coli-LPS, but not the noncancerous (B) oral keratinocytes (hTERT HAK Clone 41). For other noncancerous ARPE and MEF cells refer Fig. S5. (C) Wild-type Pg381, DPG3 and MFI induces expression of CXCR4, AKT1, FOXO1 and SDF1 in HN6 cells at 24 hours, whereas decreases the expression of BIM and FOXO3, as determined by qPCR. (D) Suppression of MFI-stimulated cell growth by inhibiting CXCR4. MFI-stimulated HN6 growth was inhibited by the CXCR4-antagonist AMD3100, but weakly or not by the DC-SIGN inhibitor gp120 after infected with DPG3. (E) MFI activates CXCR4-mediated Cellular Signaling in the direction of oncogenesis. Immunoblot analysis was used to detect the following proteins SDF-1/CXCR4, p/tAKT1, and p/tFOXO1 in E. coli-LPS, FadA+, Pg381, DPG3 and MIF treated HN6 cells compared with uninfected control, but pAKT1, pFOXO1 and SDF-1/CXCR4, were inhibited by their respective inhibitors such as MK-2206 (MK), AS1842856 (AS) and AMD3100. (F) DC-SIGN was not detectable by immunoblot in HN6 cells, thus confirming role of CXCR4 in FimA+ MFI stimulation of proliferation. The results are presented (as the mean ± SD) from one representative of four independent experiments. *P = 0.05, **P = 0.01, ***P = 0.001.

Fig 5: Model of immune homeostasis disruption and dysbiosis by P. gingivalis. DC-SIGN - TLR2/CXCR4 crosstalk activated by ligation via P. gingivalis Mfa1 - FimA, respectively, activates STAT3, resulting in downstream AKT1 activation that phosphorylates and inactivates FOXO1. Direct suppression of apoptotic activity through BIM also occurs. DC-SIGN routes P. gingivalis into non-autophagosomal compartments where they survive. Upon phosphorylation by AKT1 the FOXO proteins are excluded from the nucleus and are sequestered or degraded. FOXO inactivation contributes to extended cell survival as FOXO members activate genes encoding pro-apoptotic molecules including Bcl-2-member BIM. The resultant MDDSCs are highly resistant to apoptosis and IDO-1 competent, traveling to local and distant sites bearing the bacteria and promoting immunosuppression through induced-Tregs (FOXP3). In addition to the immunosuppressive route through DC-SIGN by DPG3 (Mfa1), \FimA (MFI) leads the direct oncogenesis route through CXCR4.