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: Actin-related protein 2/3 complex (Arp2/3) inhibitor CK-636 (CK-0944636, Cat. No. IC3650, Beijing Solarbio Science &Technology Co., Ltd), CDC42 GTPase inhibitor ML 141 (ab145603, Cat. No. 10155-1-AP, Proteintech Group, Inc. Chicago, USA), actin polymerization inhibitor: Latrunculin A (Cat. No. HY-16929, MedChem Express LLC), Rho GTPase inhibitor: Simvastatin (Cat. No. IS0170, Beijing Solarbio Science &Technology Co., Ltd.), Rac1/CDC42 activator: CN02-B (Cat. No. CN02-B, Cytoskeleton, Inc.).

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 CDC42 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. CDC42 -/- 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 CDC42 -/- A549 cells. (C) TEM quantification of M. catarrhalis invasion into wild-type and CDC42 -/- 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 CDC42 -/- 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 CDC42 -/- A549 cells compared to WT cells. (D) Quantitative comparison of F-actin/G-actin ratios in WT A549 cells and CDC42 -/- 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 CDC42 -/- 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. CDC42 -/- 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: Actin-related protein 2/3 complex (Arp2/3) inhibitor CK-636 (CK-0944636, Cat. No. IC3650, Beijing Solarbio Science &Technology Co., Ltd), CDC42 GTPase inhibitor ML 141 (ab145603, Cat. No. 10155-1-AP, Proteintech Group, Inc. Chicago, USA), actin polymerization inhibitor: Latrunculin A (Cat. No. HY-16929, MedChem Express LLC), Rho GTPase inhibitor: Simvastatin (Cat. No. IS0170, Beijing Solarbio Science &Technology Co., Ltd.), Rac1/CDC42 activator: CN02-B (Cat. No. CN02-B, Cytoskeleton, Inc.).

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