1640. Towards New Anti-Biofilm Therapies: High Mobility Group Box 1 (HMGB1) protein and its structural variants can be used to disrupt bacterial biofilms (BBs)
Session: Oral Abstract Session: Novel Therapies for Superbugs
Friday, October 5, 2018: 2:15 PM
Room: S 158
Background: BB-related infections are a major public health problem, as they are notoriously refractory to current treatments. One of the defining characteristics of BBs is the extracellular polymeric substance (EPS). Extracellular DNA and the bacterial DNABII family of proteins are key components of EPS and are crucial for BBs structural integrity. It is known that targeting DNABII proteins disrupts BBs. We hypothesized that HMGB1, a DNA-binding eukaryotic protein, could affect BBs as it binds to the same DNA structures as the DNABII proteins. HMGB1 is comprised of 3 domains, A Box, B Box and C tail, all of which have different functions. We aimed to determine in vitro the effects of HMGB1 and its individual domains against BBs.

Methods: Klebsiella pneumoniae (KP), a common cause of nosocomial infections was used for all BBs disruption assays. Human recombinant full length HMGB1 (rHMGB1; 1-215), a C45S mutation variant (mHMGB1) and the HMGB1 domains A Box (1-89), B Box (90-176), AB Boxes (1-176), B-linker Box (80-179), and B-linker Box C106S were expressed (in E.coli) and purified to >95%. To evaluate the effect of rHMGB1 and the various domains on established BBs, each protein species (200 nM) was added to pre-formed BBs at 24h. At 40h the BBs were washed, stained with LIVE/DEAD®, visualized via confocal laser scanning microscopy and images were analyzed by COMSTAT to calculate average thickness and biomass.

Results: Exogenous rHMGB1 and its individual domains, with the exception of A Box caused a significant reduction (p<0.05) in average thickness (AT) and biomass (BM) of KP biofilms as compared to untreated KP biofilms (%reduction mean ± SE in AT: 44%±0.33, 75%±0.04, 63%±0.1, 77%±0.03, 64%±0.08, 54%±0.15 and in BM: 61%± 0.01, 80%± 0.01, 68%± 0.02, 67%± 0.01, 73%± 0.02, 56%±0.02 induced by rHMGB1, mHMGB1, B-Box, B-linker Box, AB Boxes, and B-linker Box C106S, respectively).

Conclusion: Full length recombinant HMGB1 was able to significantly disrupt established KP biofilms as were all truncated HMGB1 forms containing the B Box domain and could potentially be used as a therapeutic treatment for BB-related infections.

Aspasia Katragkou, MD-PhD1, Lauren Warren, PhD2, John Buzzo, MS2 and Steven Goodman, PhD2, (1)Infectious Disease, Nationwide Children's Hospital, Columbus, OH, (2)Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH

Disclosures:

A. Katragkou, None

L. Warren, None

J. Buzzo, ProclaRx: Collaborator , Research support .

S. Goodman, ProclaRx: Collaborator and Scientific Advisor , Research support .

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