Abby Kroken Ph.D.
Assistant Professor of Microbiology & Immunology and Ophthalmology
Education
- B.S. - Biology, Wiconsin Lutheran College, Milwaukee, WI
- Ph.D - Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI
- Postdoc - University of California, Berkeley, School of Optometry. Berkeley, CA
Research Interests
Research focus: bacterial keratitis and host-microbe interaction at the ocular surface
Ocular surface epithelial cells have unique antimicrobial defenses that operate independently of apparent immune cell recruitment. There are limited approaches to investigate how epithelial cells contribute to corneal health upon challenge with microbes; most animal models depend on an injury to bypass the protective properties of the epithelium. Thus, I use and develop models where intact epithelium is left in place (e.g., a surface blot, mucin removal, or even animal models of contact lens wear). This allows me to examine how microbial encounters unfold, and how the cornea maintains health. My research approach leverages our ability to visualize both the position and activities of individual bacteria in the cornea, which is a clear, accessible tissue. Our field also has access to primary cell culture and excellent immortalized cell lines, allowing us to investigate molecular mechanisms and reserve only key experiments for animal models.
My top priority is devoted to investigation of Pseudomonas aeruginosa, an important ocular pathogen, and a successful intracellular pathogen of epithelial cells. Understood by much of the field to operate primarily as an extracellular pathogen, P. aeruginosa has also been observed inside epithelial cells; these findings have been published at a modest but consistent rate since the 1980’s, culminating in just over 100 publications to date. We employ time-lapse imaging for visualizing P. aeruginosa invasion into cultured corneal epithelial cells to interrogate this process mechanistically. We also consider the implications of unappreciated intracellular bacteria in all types of experiments; thus, the lab routinely ensures that we check whether bacterial internalization occurs, and whether our experimental manipulations change its probability. We are committed to reporting on this phenomenon in all our research questions.
We develop high-throughput, reproducible, and open-source analysis pipelines for microscopy data, routinely analyzing data sets containing >1000 cells per condition to ensure rigor and reproducibility. We develop ImageJ macros and Python scripts to automate measurement. This enables us to measure and report heterogeneity inherent in all experimental systems.
Publications/Research Listings
Resko ZJ, Mazurek RF, Thota AV, Kroken AR. Evidence for Intracellular Pseudomonas aeruginosa. J Bacteriol. 2024 May 23;206(5):e0010924. doi: 10.1128/jb.00109-24. Epub 2024 Apr 10. PMID: 38597609; PMCID: PMC11112991.
Kroken AR, Klein KA, Mitchell PS, Nieto V, Jedel EJ, Evans DJ, Fleiszig SMJ. Intracellular replication of Pseudomonas aeruginosa in epithelial cells requires suppression of the caspase-4 inflammasome. mSphere. 2023 Aug 17:e0035123. PMID: 37589460.
Kroken AR, Gajenthra Kumar N, Yahr TL, Smith BE, Nieto V, Horneman H, Evans DJ, Fleiszig SMJ. Exotoxin S secreted by internalized Pseudomonas aeruginosa delays lytic host cell death. PLoS Pathog. 2022 Feb 7;18(2):e1010306. PMID: 35130333; PMCID: PMC8853526.
Kumar NG, Nieto V, Kroken AR, Jedel E, Grosser MR, Hallsten ME, Mettrucio MME, Yahr TL, Evans DJ, Fleiszig SMJ. Pseudomonas aeruginosa Can Diversify after Host Cell Invasion to Establish Multiple Intracellular Niches. mBio. 2022 Dec 20;13(6):e0274222. Epub 2022 Nov 14. PMID: 36374039; PMCID: PMC9765609.
Wan SJ, Datta A, Flandrin O, Metruccio MME, Ma S, Nieto V, Kroken AR, Hill RZ, Bautista DM, Evans DJ, Fleiszig SMJ. Nerve-associated transient receptor potential ion channels can contribute to intrinsic resistance to bacterial adhesion in vivo. FASEB J. 2021 Oct;35(10):e21899. doi: 10.1096/fj.202100874R. PMID: 34569661; PMCID: PMC8486357.
Nieto V, Kroken AR, Grosser MR, Smith BE, Metruccio MME, Hagan P, Hallsten ME, Evans DJ, Fleiszig, SMJ. A novel form of intracellular bacterial motility performed by Pseudomonas aeruginosa. 2019. MBio, Aug 20;10(4). pii: e02880-18. PMID: 31431558; PMCID: PMC6703432.
Fleiszig SMJ, Kroken AR, Nieto V, Grosser MR, Wan SJ, Metruccio MME, Evans DJ. Contact lens related corneal infection: Intrinsic resistance and its compromise. Prog Retin Eye Res. 2020 May;76:100804. Epub 2019 Nov 20. PMID: 31756497; PMCID: PMC7237316.
Kroken AR, Chen CK, Evans DJ, Yahr, TL, Fleiszig SMJ. The impact of ExoS on Pseudomonas aeruginosa internalization by epithelial cells is independent of fleQ and correlates with bistability of type three secretion system gene expression. 2018. MBio, May 1;9(3). pii: e00668-18. PMID: 29717012; PMCID: PMC5930308.
Metruccio MME, Wan SJ, Horneman H, Kroken AR, Sullivan AB, Truong TN, Mun JJ, Tam CKP, Frith R, Welsh L, George MD, Morris CA, Evans DJ, Fleiszig SMJ. A novel murine model for contact lens wear reveals clandestine IL-1R dependent corneal parainflammation and susceptibility to microbial keratitis upon inoculation with Pseudomonas aeruginosa. 2018. The Ocular Surface, 17 (1), 119-133. PMID: 30439473; PMCID: PMC6365008.