Journal: bioRxiv
Article Title: Porphyromonas gingivalis activates Heat-Shock-Protein 27 to drive a LC3C-specific probacterial form of select autophagy that is redox sensitive for intracellular bacterial survival in human gingival mucosa
doi: 10.1101/2024.07.01.601539
Figure Lengend Snippet: HSp27 Presence Permits the Prolonged Existence of LC3C-characterized, P. gingivalis Specific Autophagosomes by Hampering Canonical Autolysosomal Fusion in Primary GECs. ( A ) Human primary GECs were transfected with mCherry-eGFP-LC3C for 48 h. Select GECs were also treated with 1 uM of the autophagolysosomal fusion inhibitor Bafilomycin A1, 1 uM Pepstatin A, or 5 mM 3-MA. Others were treated with Hsp27 siRNA (100nM) for 24 h. P. g was added at MOI 100 to GECs, which were incubated for 24 h. ( A ) GECs were then stained for P. g (mouse anti- P.g; Alexa 405; blue) and were mounted. GECs were then imaged via confocal microscopy (Leica DM6 CS Stellaris 5 Confocal/Multiphoton System) at 63x. ( Ai ) Imaris was used to obtain a zoomed 63x orthogonal image of 24 h P. g infection and measure the high co-localization levels between P. g and the LC3C Reporter System. P. g localized readily to the LC3C construct, with a Pearson correlation coefficient of 0.82. (B) Separately, GECs were additionally stained for P. g (rabbit anti-P . gingivalis ; Alexa 488; green) and LAMP-1 (mouse anti-LAMP-1; Alexa 568; red) and were imaged. The range of all z-stacks was kept consistent and representative images were selected from the mid-ranged sections. Scale bar is 40 µm for 63x Magnification. ( Bi ) Imaris was used to obtain a zoomed 63x orthogonal image of 24 h P. g infection and measure the co-localization levels between P. g and LAMP-1 in infected and treated GECs. While P. g infected GECs did not exhibit high co-localization with LAMP-1 (Pearson correlation coefficient of .25), their HSp27-depleted counterparts did, with an average Pearson correlation coefficient of 0.83. The Scale bar is 20 µm for 63x Magnification. ( C ) Finally, GECs treated with autophagic inhibitors were targeted for P. g (rabbit anti- P. g ; goat anti-rabbit Ultra Small Gold Antibody) and labeled P. g was found to be readily ensconced within double-membraned autophagosomes in GECs. Representative transmission electron microscopy images of P. g -infected GECs were taken at 80 kV and 30000x or 100000x magnification. Following HSp27 depletion, P. g appeared to readily start to degrade, however treatment with late-stage autophagic inhibitors Bafilomycin A1 or Pepstatin A appeared to rescue P. g from degradation. Representative transmission electron microscopy images of P. g -infected GECs were taken at 80 kV and 30000x or 100000x magnification. Scale bar is 800 nm.
Article Snippet: Membranes were then blocked in Tris-buffered saline with 0.1% Tween 20 (TBST) containing 2% Bovine serum albumin (BSA) for 1 h. Following blocking, membranes were incubated in polyclonal rabbit anti-LC3C antibody (ProteinTech, 18726-1-AP; 1:1000), anti-UVRAG antibody (Invitrogen, PA5-35213; 1:1000), anti-Beclin 1 rabbit antibody (Cell Signaling Technology, 3495; 1:1000), and anti-ATG14 rabbit antibody (Cell Signaling Technology, 96752; 1:1000), which were detected via anti-rabbit (Cell Signaling Technology, 7076; 1:2000) or anti-mouse HRP-conjugated secondary antibody (Cell Signaling Technology, 7074; 1:2000).
Techniques: Transfection, Incubation, Staining, Confocal Microscopy, Infection, Construct, Labeling, Transmission Assay, Electron Microscopy