Joseph Horzempa

Assistant Professor of Biology



  • BS, California University of Pennsylvania, 2000
  • MS, California University of Pennsylvania, 2002
  • PhD, Duquesne University, 2006
  • Postdoctoral, University of Pittsburgh School of Medicine, 2006-2011


  •          BIO 124 – Biological Principles                                              
  •          BIO 124-xx – Biological Principles Active Study                          
  •          BIO 216 – Microbiology (for Healthcare Professionals)      
  •          BIO 220 – Scientific Methodologies                                  
  •          BIO 325 – General Microbiology                                       
  •          BIO 326 – General Microbiology Laboratory                    
  •          BIO 461 – Molecular Biology Laboratory                            
  •          BIO 462 – Microbial Pathogenesis                                       
  •          BIO 472 – Cell Biology                                                                
  •          BIO 478 – Special Topics – Fluorescence Microscopy  
  •          PA 504 – Research I                                   
  •          PA 505 – Research II    

Current Research Projects:

Francisella tularensis is a highly infectious microorganism with fewer than 10 inhaled bacteria causing the fatal disease tularemia.  This bacterium has been weaponized and could be used for bioterrorism, prompting the Center for Disease Control and Prevention to classify F. tularensis as a Category A biodefense agent.  In addition to the threat of an intentional release, F. tularensis causes a variety of naturally occurring human infections that can be acquired by inhalation, arthropod bites, oropharyngeal exposure, or by contact.  My long term goals involve understanding the pathogenesis, persistence, and transmission of F. tularensis.  Ultimately, I am interested in identifying novel therapeutics to combat this pathogen and other bacterial pathogens.

The virulence of F. tularensis has principally been associated with this organism’s ability to replicate within phagocytic cells of the innate immune system, such as macrophages. In addition to macrophages, F. tularensis can invade and replicate in a range of non-phagocytic host cells such as alveolar epithelial cells, kidney epithelial cells, hepatocytes, and fibroblasts. F. tularensis also employs mechanisms to suppress the host innate immune response, resist complement, and inhibit macrophage and neutrophil effector functions. The ability of F. tularensis to detect and respond to environmental signals contributes to this organism’s success as a pathogen. My work has shown that mammalian temperature modulates virulence gene expression. Differential responses to temperature by F. tularensis, as determined by microarray analysis, provided a focused list of relevant candidate virulence determinants to investigate further.  These virulence factors will be primary therapeutic targets.

Uptake of F. tularensis into both macrophages and non-phagocytes is mediated by the host cell’s endocytic machinery.  Recently, I made the observation that Francisella also invades erythrocytes during infection – cells incapable of endocytosis.  A focus of my research program involves examination of the molecular mechanisms facilitating erythrocyte invasion by F. tularensis and the biological role of this phenomenon.  Both erythrocyte and bacterial factors will be investigated for their contribution toward invasion.  To elucidate the biological role of erythrocyte invasion, I intend to investigate whether erythrocyte invasion contributes to the pathogenesis of F. tularensis.   Because erythrocytes are long-lived cells, I will also explore a role in disease persistence for invasion of red blood cells.  Other pathogenic bacteria that invade erythrocytes do so to enhance transmission by arthropod vectors, such as ticks.  Therefore, I will examine a role in enhancing arthropod transmission.  Furthermore, I have established collaborations that will allow me to examine clinical specimens from tularemia patients to assess the level of erythrocyte invasion during human infection.  The information generated in these studies will enhance our understanding of this pathogen’s biology during different stages of infection.  Also, by understanding how the erythrocyte is manipulated to allow F. tularensis access to its intracellular space, we will gain insight into the cell biology of red blood cells.

My research agenda also involves investigating the pathogenesis of the opportunistic pathogen, Pseudomonas aeruginosa.  In addition, I am developing and characterizing a novel live vaccine platform that can be engineered to elicit protection against a variety of bacterial pathogens including P. aeruginosa.

Laboratory Personnel:

Deanna Schmitt, PhD – Postdoctoral Research Associate
x8576     [email protected]


Beheshti A, Lucas L, Dunz T, Haydash M, Chiodi H, Edmiston B, Ford C, Bohn N, Stein JH, Berrett A, Sobota B, Horzempa J^.  An Evaluation of Naloxone Use for Opioid Overdoses in West Virginia: A Literature Review.  American Medical Journal.  2015 In press.  ^corresponding author

Aston R, Durkin A, Harris K, Mace A, Moore S, Smith B, Soult E, Wright M, Yothers D, Latos D, Horzempa J^.  Considerations for a Primary Care Physician Assistant in Treating Kidney Transplant Recipients. Quality in Primary Care 2015 Feb; 23(1): 40-6. ^corresponding author

Robinson CM, Kobe BN, Schmitt DM, Phair B, Gilson T, Jung JY, Roberts L, Liao J, Camerlengo C, Chang B, Davis M, Figurski L, Sindeldecker D, Horzempa J^. Genetic engineering of Francisella tularensis LVS for use as a novel live vaccine platform against Pseudomonas aeruginosa infections. Bioengineered. 2015 Mar 4;6(2):82-8. doi: 10.1080/21655979.2015.1011033. PMID: 25617059. ^corresponding author

Schmitt DM, O’Dee DM, Cowan BN, Birch JW, Mazzella LK, Nau GJ, Horzempa J^. The use of resazurin as a novel antimicrobial agent against Francisella tularensis. Front Cell Infect Microbiol. 2013 Dec 6;3:93. doi: 10.3389/fcimb.2013.00093. eCollection 2013. PMID: 24367766; PMCID: PMC3853850. ^corresponding author

Kraft JD*, Horzempa J*, Davis C, Jung JY, Peña MM, Robinson CM. Neonatal macrophages express elevated levels of interleukin-27 that oppose immune responses. Immunology. 2013 Aug;139(4):484-93. doi: 10.1111/imm.12095. PMID: 23464355; PMCID: PMC3719065. *These authors contributed equally

Schmitt DM, O’Dee DM, Brown MJ, Horzempa J, Russo BC, Morel PA, Nau GJ. Role of NK cells in host defense against pulmonary type A Francisella tularensis infection. Microbes Infect. 2013 Mar;15(3):201-11. doi: 10.1016/j.micinf.2012.11.008. Epub 2012 Dec 1. PMID: 23211929.

Schmitt DM, O’Dee DM, Horzempa J, Carlson PE Jr, Russo BC, Bales JM, Brown MJ, Nau GJ. A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy. PLoS One. 2012;7(2):e31172. doi: 10.1371/journal.pone.0031172. Epub 2012 Feb 15. PMID: 22355343; PMCID: PMC3280287.

Russo BC, Horzempa J, O’Dee DM, Schmitt DM, Brown MJ, Carlson PE Jr, Xavier RJ, Nau GJ. A Francisella tularensis locus required for spermine responsiveness is necessary for virulence. Infect Immun. 2011 Sep;79(9):3665-76. doi: 10.1128/IAI.00135-11. Epub 2011 Jun 13. PMID: 21670171;  PMCID: PMC3165480.

Horzempa J, O’Dee DM, Stolz DB, Franks JM, Clay D, Nau GJ. Invasion of erythrocytes by Francisella tularensis. J Infect Dis. 2011 Jul 1;204(1):51-9. doi: 10.1093/infdis/jir221. PMID: 21628658; PMCID: PMC3105038.

Kalivoda EJ, Horzempa J, Stella NA, Sadaf A, Kowalski RP, Nau GJ, Shanks RM. New vector tools with a hygromycin resistance marker for use with opportunistic pathogens. Mol Biotechnol. 2011 May;48(1):7-14. doi: 10.1007/s12033-010-9342-x. PMID: 20972648; PMCID: PMC3617578.

Qutyan M, Henkel M, Horzempa J, Quinn M, Castric P. Glycosylation of pilin and nonpilin protein constructs by Pseudomonas aeruginosa 1244. J Bacteriol. 2010 Nov;192(22):5972-81. doi: 10.1128/JB.00007-10. Epub 2010 Sep 10. PMID: 20833803; PMCID: PMC2976441.

Horzempa J, O’Dee DM, Shanks RM, Nau GJ. Francisella tularensis ΔpyrF mutants show that replication in nonmacrophages is sufficient for pathogenesis in vivo. Infect Immun. 2010 Jun;78(6):2607-19. doi: 10.1128/IAI.00134-10. Epub 2010 Apr 12. PMID: 20385757; PMCID: PMC2876533.

Horzempa J, Shanks RM, Brown MJ, Russo BC, O’Dee DM, Nau GJ. Utilization of an unstable plasmid and the I-SceI endonuclease to generate routine markerless deletion mutants in Francisella tularensis. J Microbiol Methods. 2010 Jan;80(1):106-8. doi: 10.1016/j.mimet.2009.10.013. Epub 2009 Oct 29. PMID: 19879904; PMCID: PMC3034693.

Carlson PE Jr*, Horzempa J*, O’Dee DM*, Robinson CM, Neophytou P, Labrinidis A, Nau GJ. Global transcriptional response to spermine, a component of the intramacrophage environment, reveals regulation of Francisella gene expression through insertion sequence elements. J Bacteriol. 2009 Nov;191(22):6855-64. doi: 10.1128/JB.00995-09. Epub 2009 Sep 11. PMID: 19749055; PMCID: PMC2772466. *These authors contributed equally

Horzempa J, Carlson PE Jr, O’Dee DM, Shanks RM, Nau GJ. Global transcriptional response to mammalian temperature provides new insight into Francisella tularensis pathogenesis. BMC Microbiol. 2008 Oct 8;8:172. doi:10.1186/1471-2180-8-172. PMID: 18842136; PMC2576331.

Horzempa J, Held TK, Cross AS, Furst D, Qutyan M, Neely AN, Castric P. Immunization with a Pseudomonas aeruginosa 1244 pilin provides O-antigen-specific protection. Clin Vaccine Immunol. 2008 Apr;15(4):590-7. doi: 10.1128/CVI.00476-07. Epub 2008 Feb 13. PMID: 18272666; PMCID: PMC2292668.

Horzempa J, Tarwacki DM, Carlson PE Jr, Robinson CM, Nau GJ. Characterization and application of a glucose-repressible promoter in Francisella tularensis. Appl Environ Microbiol. 2008 Apr;74(7):2161-70. doi: 10.1128/AEM.02360-07. Epub 2008 Feb 1. PMID: 18245238; PMCID: PMC2292608.

Horzempa J, Dean CR, Goldberg JB, Castric P. Pseudomonas aeruginosa 1244 pilin glycosylation: glycan substrate recognition. J Bacteriol. 2006 Jun;188(12):4244-52. PMID: 16740931; PMCID: PMC1482975.

Smedley JG 3rd*, Jewell E*, Roguskie J*, Horzempa J*, Syboldt A, Stolz DB, Castric P. Influence of pilin glycosylation on Pseudomonas aeruginosa 1244 pilus  function. Infect Immun. 2005 Dec;73(12):7922-31. PMID: 16299283; PMCID: PMC1307089. *These authors contributed equally

Horzempa J, Comer JE, Davis SA, Castric P. Glycosylation substrate specificity of Pseudomonas aeruginosa 1244 pilin. J Biol Chem. 2006 Jan 13;281(2):1128-36. Epub 2005 Nov 11. PMID: 16286455; PMCID: PMC2248725.


Interests and Hobbies:

I enjoy spending time with my family, playing guitar, sports, and being the household handyman.

Undergraduate Researchers:

Horzempa Lab

Students (not ordered): Adam Kenney, Aleksandr Florjanczyk, Alex Hayden, Alyssa Ebert, Anna Gaughenbaugh, Anthony Sako, Ashley Haught, Austin Cusick, Brandon Chang, Caleb Martin, Chelsea Camerlengo, David Scammell, Devin Sindeldecker, Edward Beaumont, Elliot Collins, Emily Clark, Jenna Ingram, Jennifer Hickman, Jessica Payne, Jialin Liao, Kevin Cook, Kristen Sikorsky, Leah Figurski, Makayla Smith, Matthew Ford, Rebecca Barnes, Taylor Rogerson

Office: Arnett Hall 207
Phone: (304) 336-8284
[email protected]

West Liberty University
208 University Drive
College Union Box 139
West Liberty, WV 26074