Journal: Frontiers in Immunology

Article Title: The Rho GTPase signaling pathway modulates Moraxella catarrhalis invasion into human respiratory epithelial cells by regulating actin polymerization

doi: 10.3389/fimmu.2026.1730864

Figure Lengend Snippet: CDC42 -/- A549, Rac1 -/- A549, ArpC2 -/- A549 and ArpC4 -/- A549 cell lines.

Article Snippet: Among them, the invasion assay results showed that compared with wild-type A549 cells, the number of bacteria invading Rac1 -/- A549 cells by 73-OR and ATCC 25238 decreased significantly ( ); For the 73-OR strain, invasion counts were substantially lower in Rac1 -/- A549 cells (Mean:9,833 ± 3,436 CFU/well) compared to WT A549 cells (Mean: 76, 562 ± 53, 978 CFU/well).

Techniques:

Journal: Frontiers in Immunology

Article Title: The Rho GTPase signaling pathway modulates Moraxella catarrhalis invasion into human respiratory epithelial cells by regulating actin polymerization

doi: 10.3389/fimmu.2026.1730864

Figure Lengend Snippet: Critical role of Rac1 in the Rho GTPase signaling pathway during M. catarrhalis invasion into A549 cells. (A) Comparison of invasion counts of M. catarrhalis strains 73-OR and ATCC 25238 into WT A549 cells vs. Rac1 -/- A549 cells. Data are presented as mean ± standard error (SE)from three independent biological replicates (n=3). Statistical significance was determined using an unpaired Student’s t-test. To accurately assess the magnitude of the impact given the limited sample size, effect sizes (Cohen’s d) and mean differences are reported alongside P-values. (B) Transmission electron micrographs (TEM) of 73-OR and ATCC 25238 invading WT A549 cells and Rac1 -/- A549 cells. (C) TEM quantification of M. catarrhalis invasion into wild-type and Rac1 -/- A549 cells. Invasion counts for M. catarrhalis strains 73-OR and ATCC 25238 were quantified by counting the number of bacteria internalized within wild-type (WT) and Rac1 -/- A549 cells via Transmission Electron Microscopy (TEM). Data represent the mean ± standard error(SE) from three independent biological replicates (n=3). Within each biological replicate, three random microscopic fields at the same magnification were selected and counted. Statistical significance between groups was determined using the non-parametric Mann-Whitney U test. Both 73-OR and ATCC 25238 strains showed a significant reduction in invasion into Rac1 -/- A549 compared to WT cells. (D) Quantitative comparison of F-actin/G-actin ratios in WT A549 cells and Rac1 -/- A549 cells post-infection with M. catarrhalis strains 73-OR and ATCC 25238. Data are presented as the mean± standard error(SE) from three independent biological replicates (n=3). Statistical comparison between groups was performed using an unpaired Student’s t-test. (E) Immunofluorescence analysis of F-actin polymerization in A549 cells post-infection.Wild-type (WT) and Rac1 -/- A549 cells were challenged with M. catarrhalis strains 73-OR and ATCC 25238, fixed, and stained. Blue: nuclei; Green: F-actin. (F) Analysis of microfilament expression levels in WT A549 cells vs. Rac1 -/- A549 cells following infection with 73-OR and ATCC 25238. Data are presented as the mean ± standard error(SE) from three independent biological replicates (n=3). Statistical comparison between groups was performed using an unpaired Student’s t-test.

Article Snippet: Among them, the invasion assay results showed that compared with wild-type A549 cells, the number of bacteria invading Rac1 -/- A549 cells by 73-OR and ATCC 25238 decreased significantly ( ); For the 73-OR strain, invasion counts were substantially lower in Rac1 -/- A549 cells (Mean:9,833 ± 3,436 CFU/well) compared to WT A549 cells (Mean: 76, 562 ± 53, 978 CFU/well).

Techniques: Comparison, Transmission Assay, Bacteria, Electron Microscopy, MANN-WHITNEY, Infection, Immunofluorescence, Staining, Expressing

Journal: Cell Death Discovery

Article Title: Primed mesenchymal stem cells attenuate schistosomiasis fibrosis by enhancing macrophage subset switching and efferocytosis via Itgb2-Rac1 axis

doi: 10.1038/s41420-026-02947-w

Figure Lengend Snippet: MoMϕs from infected mice were first incubated with MSCs or primed MSCs, respectively, and then added apoptotic neutrophils (or Dil-labeled apoptotic neutrophils). Macrophages were collected at different efferocytosis times, and the mRNA levels of Itgb2 and Rac1were detected by qPCR ( A ) after 12 h phagocytosis; prior to the start of phagocytosis, macrophages were incubated with CD18 neutralizing antibody(2.5 μg/ml) for 3 h to block Itgb2 signal pathway, and then the mRNA levels of Rac-1 were detected by qPCR after 12 h phagocytosis and activity of Rac1 in macrophages was determined by G-LISA after 1 h of phagocytosis ( B ); after blocking Itgb2 signal pathway, the efferocytosis efficiency of macrophages was detected by immunofluorescence for MerTK (green) and Dil-labeled apoptotic neutrophils (red), Representative images of efferocytosis cells ( C1 ), Scale bars, 100 µm, and the percentage of macrophages engulfing apoptotic neutrophils ( C2 ). n = 3; Data are presented as mean ± SEM (* P < 0.05, ** P < 0.01 and n.s. not significant).

Article Snippet: After co-coculture for indicated times, BMDMs were collected, and active Rac1 was measured using the Rac1 G-LISA Activation Assay kit (BK126, Cytoskeleton) according to the manufacturer’s instructions.

Techniques: Infection, Incubation, Labeling, Blocking Assay, Activity Assay, Immunofluorescence

Journal: Cell Death Discovery

Article Title: Primed mesenchymal stem cells attenuate schistosomiasis fibrosis by enhancing macrophage subset switching and efferocytosis via Itgb2-Rac1 axis

doi: 10.1038/s41420-026-02947-w

Figure Lengend Snippet: MoMϕs from infected mice were first incubated with primed MSCs or without MSCs for 24 h (for blocking test, macrophages were still exposed to neutralizing antibody against CD18 or Rac1 inhibitor NSC23766 3 h prior to the start of efferocytosis), and then apoptotic neutrophils were added. Macrophages were collected after 12 h phagocytosis, and the mRNA levels of Rac1, IL-1β, Tnf-ɑ, TFG-β, Cx3cr1, Mmp2, Mmp9, and Il10 were detected by qPCR. n = 3; Data are presented as mean ± SEM (* P < 0.05, ** P < 0.01, *** P < 0.001 and n.s. not significant).

Article Snippet: After co-coculture for indicated times, BMDMs were collected, and active Rac1 was measured using the Rac1 G-LISA Activation Assay kit (BK126, Cytoskeleton) according to the manufacturer’s instructions.

Techniques: Infection, Incubation, Blocking Assay