Stephanie L. Silva-Del Toro
University of Iowa
Iowa City, IA
Mechanisms of H. Pylori-Induced Neutrophil Nuclear Hypersegmentation
Stephanie L. Silva-Del Toro*, University of Iowa and Lee-Ann Allen, University of Iowa Inflammation Program
Helicobacter pylori is a human pathogen that resides in the gastric mucosa, eliciting a neutrophil (PMN) dominant inflammatory response that can progress to peptic ulcer disease or gastric cancer. PMNs exhibit significant functional and phenotypic plasticity, and we recently demonstrated that these cells undergo N1-like-subtype differentiation in-vitro following H. pylori infection. This phenotype is notable for profound nuclear hypersegmentation and a proinflammatory and cytotoxic phenotype. Our objective is to define the underlying mechanisms with a focus on nuclear hypersegmentation. We have shown that direct infection and both host and bacterial transcription and protein synthesis are essential. Recent studies using nocodazole and taxol identified an additional requirement for microtubule
(MT) dynamics. Moreover, STED-super-resolution microscopy analysis showed that MTs are longer and more abundant following H. pylori infection. Inhibition by Brefeldin A and Exo1 suggested an additional role for anterograde transport, and to our surprise revealed unexpected effects of Brefeldin A on PMN microtubule dynamics. Finally, we used antibodies against lamin B receptor and STED-super-resolution microscopy imagining to analyze PMN nuclei in unprecedented detail. These data demonstrate that the volume of the H. pylori infected PMN nucleus is significantly increased and the PMN nuclear volume is altered when cells were treated with MT disruptors. The uniformity of distribution of lamin B receptor in the nuclear membrane was also evaluated and it is altered by drugs that manipulate MT dynamics. Altogether, our data provide fundamental insight into the mechanisms that regulate PMN nuclear morphology as well as the consequences of H. pylori infection.
Honolulu, October 31 - November 2, 2019
