February 2026
Mireya Represa Perez presented her PhD research proposal.

November 2025
Our protocol “High-sensitivity In Situ Hybridization DNAscope for Detection of Papillomavirus or Epstein-Barr Virus Genomes Combined with Immunofluorescent Staining in Adherent Cells” has been accepted to be publish in “In Situ Hybridization Protocols. Molecular Methods in Biology”, Springer Nature.

Mireya Represa Perez presented her study as an oral presentation at the South-Central Branch of American Society for Microbiology Annual Meeting 2025, Starkville, MS.

Katarzyna Zwolinska presented her poster at the South-Central Branch of American Society for Microbiology Annual Meeting 2025, Starkville, MS.

July 2025
Timothy Keiffer gave an oral presentation during the 2025 DNA Tumor Virus Meeting in Madison, WI

Anand Kushwaha, Katarzyna Zwolinska and Mireya Represa Perez presented their posters during 2025 DNA Tumor Virus Meeting in Madison, WI

Katarzyna Zwolinska co-chaired the Viral Infection/Life Cycle Session during the 2025 DNA Tumor Virus Meeting, Madison, WI.

June 2025
Anand Kushwaha was awarded the two year Ike Muslow Postdoctoral Fellowship Award.

May 2025
Mireya Represa Perez received the Martin J. Sapp Travel Award to attend DNA Virus Tumor Meeting 2025.

February 2025
Mireya Represa Perez passed her PhD Preliminary and Qualifying Exams.

December 2024
Our study titled " HPV16 entry requires dynein for minus-end transport and utilizes kinesin Kif11 for plus-end transport along microtubules during mitosis" was published in the Journal of Virology.

Human papillomavirus (HPV) infection, particularly with so-called high-risk HPV types such as HPV16 and HPV18, is responsible for approximately 5% of all human cancers worldwide. Despite the availability of a prophylactic vaccine since 2006, HPV continues to contribute to significant morbidity and mortality in the human population. This is due to the long latency period between infection and disease onset, limited vaccination coverage, and type-restricted neutralizing immune responses. Therefore, a better understanding of HPV biology is essential for the development of better prophylactic and therapeutic approaches.

HPV are non-enveloped viruses harboring a circular double-stranded DNA genome of approximately 8,000 bp. They are highly tissue-specific and only replicate in keratinocytes of the skin and mucosa. Their life cycle begins by establishing infection in the basal cell of this stratified epithelia, gaining access through abrasions, wounds and microlesions. Once infection is established in the basal keratinocytes, the virus goes latent with a restricted viral replication and transcription program. When HPV harboring keratinocytes enter into the terminal differentiation program, the productive phase of the life cycle begins finally resulting in the generation of progeny virions in the uppermost layers of this stratified epithelium. This may result in the formation of skin, oral and genital warts. In rare cases of persistency, infection with high-risk HPV types can induce the development of tumors such as cervical, anogenital, and oropharyngeal squamous cell carcinoma.

Our current research focuses on the early events of human papillomavirus (HPV) life cycle, including the high-risk HPV16. We study the late trafficking and the establishment of infection, the viral genome amplification and maintenance, and the host-virus interactions in basal keratinocytes of skin and mucosa. Recently we found that maintaining the stable level of HPV genome copy number is strictly regulated over the cell cycle. The viral genome is amplified during the S/G2 phase to the high numbers, however, during the mitosis majority of the genomes are lost to the cytosol where they are degraded via lysosome-dependent manner during G1 phase. We are currently investigating the modes of the degradation of HPV genomes in the cytoplasm, the host immune system response to the viral DNA present in the cytosol and the mechanisms of the viral genome attachment to mitotic chromosomes, as the main processes responsible for the viral persistence in infected cells.

ONGOING GRANTS

R01CA211576-06A1 NIH-NCI (04/01/2024 – 03/31/2029). Immediate early events of the HPV life cycle. Zwolinska K., LSU Health Shreveport, LA (PI)

R01A1164683-04 NIH-NIAID (07/01/2021 – 06/30/2027). Human papillomavirus entry: late trafficking and establishment of infection. Zwolinska K. (PI), Yurochko A. (Co-PI), LSU Health Shreveport, LA.

R21DE032626-02 NIDCR (07/03/2023 – 12/31/2026). Epigenetics of dysfunctional oral epithelium in people living with HIV and risk for HPV infection. Weinberg A., Case Western Reserve University, Cleveland, OH.

Selected Publications

1. Bienkowska-Haba M, Scott RS, Sapp M, Zwolinska K. High-sensitivity In Situ Hybridization DNAscope for Detection of Papillomavirus or Epstein-Barr Virus Genomes Combined with Immunofluorescent Staining in Adherent Cells. In Situ Hybridization Protocols. Molecular Methods in Biology, Springer Nature. 2026, book chapter accepted.

2. Keiffer TR, DiGiuseppe S, Guion L, Bienkowska-Haba M, Zwolinska K, Siddiqa A, Kushwaha A, Sapp MJ. HPV16 Entry Requires Dynein for Minus-End Transport and Utilizes Kinesin Kif11 for Plus-End Transport Along Microtubules During Mitosis. J. Virol. 2025, Jan 31;99(1):e0093724. doi.org/10.1128/jvi.00937-24.

3. Zwolinska K, Bienkowska-Haba M, Keiffer T, Scott RS, Sapp M. Experimental support for human papillomavirus genome amplification early after infectious delivery. J Virol. 2023 Jun 29;97(6): e0021423.doi: 10.1128/jvi.00214-23.

4. Bienkowska-Haba, Zwolinska K, Keiffer T, Scott RS, Sapp M. Human Papillomavirus Genome Copy Number Is Maintained by S-Phase Amplification, Genome Loss to the Cytosol during Mitosis, and Degradation in G1 Phase. J. Virol. 2023 Feb 28;97(2): e0187922. doi: 10.1128/jvi.01879-22.

5. Myers JE, Zwolinska K, Sapp M, Scott RS. An exonuclease V-qPCR assay to analyze the state of the human papillomavirus 16 genome in cell lines and tissues. Curr Protoc Microbiol. 2020; 59(1):e119. doi: 10.1002/cpmc.119.

6. Bienkowska-Haba M, Luszczek W, Zwolinska K, Scott RS, Sapp M. Genome-Wide Transcriptome Analysis of Human Papillomavirus 16-Infected Primary Keratinocytes Reveals Subtle Perturbations Mostly due to E7 Protein Expression. J Virol. 2020 Jan 17;94(3). doi: 10.1128/JVI.01360-19.

7. Myers JE, Guidry JT, Scott ML, Zwolinska K, Raikhy G, Prasai K, Bienkowska-Haba M, Bodily JM, Sapp MJ, Scott RS. Detecting episomal or integrated human papillomavirus 16 DNA using an exonuclease V-qPCR-based assay. Virology. 2019 Aug 22;537:149-156. doi: 10.1016/j.virol.2019.08.021.

Available Positions

We are constantly looking for post-doctoral fellows and graduate students to join our program. We are offering a highly collaborative work environment, competitive compensation and highly innovative research projects.

Students interested in working in our Department should visit our Graduate Program website.

Those interested in postdoctoral work should contact Dr. Zwolinska at katarzyna.zwolinska@lsuhs.edu.

Contact Us

LSU Health Shreveport
Department of Microbiology & Immunology
1501 Kings Hwy, Shreveport, LA 71103

Email: katarzyna.zwolinska@lsuhs.edu
Office: 318-675-4333

The Zwolinska Laboratory builds upon a long-standing research program established and carried forward for more than 20 years by Dr. Sapp and his research group. Following the unfortunate passing of Dr. Sapp in October 2024, Dr. Zwolinska was entrusted by the Department of Microbiology and Immunology to lead his projects. The laboratory is dedicated to preserving Dr. Sapp’s scientific legacy and continuing his research, honoring him as an outstanding scientist, mentor, and leader.

Martin Sapp, PhD (February 2, 1960 – October 21, 2024) served as Chair of the Department of Microbiology and Immunology at LSU Health Shreveport from 2018 until 2024. Dr. Sapp joined LSU Health Shreveport in 2005 as an Associate Professor, where he established his laboratory focused on the life cycle of Human papillomavirus (HPV). He was promoted to Professor in 2011. During his career, he held the Willis-Knighton Endowed Chair for Molecular Biology and previously held the Mingyu Ding Memorial Professorship of Microbiology and Immunology.

Dr. Sapp was an accomplished scientist who served as the principal investigator (PI) on numerous grant awards. At the time of his passing, he was the PI on two grants from the National Institutes of Health (R01) and a Co-PI on an NIH R21 grant supporting research on the molecular biology of Human papillomavirus and the etiology of cervical cancer.

Dr. Sapp was widely published and contributed to the scientific community through his editorial work. For more than eleven years, he served on the editorial boards of the journals Virology and Virology Research.

Dr. Sapp received his master’s in biology and his Doctorate in Biology from the University Konstanz in Germany followed by further study in medical microbiology. He was a postdoctoral fellow in the laboratory of Dr. R. Knippers in Konstanz, Germany and of Dr. A. Worcel at the University of Rochester, New York. Dr. Sapp also completed a postdoctoral fellowship from the Deutsche Forschungsgemeinschaft, Germany. He began his academic career as an Assistant Professor at the Institut für Medizinische Mikrobiologie und Hygiene, Mainz during which time he became the Cofounder, CEO and CSO of Virofem Diagnostica GmbH.

He was a colleague and mentor who could be counted on to assist anytime his intellectual knowledge or time was needed as evidenced by his efforts in setting up the COVID 19 testing lab at LSUHS in record time. He was kind and forthright and will be fondly remembered for his immense contributions to LSU Health Shreveport.

Research

Infection with certain human papillomavirus (HPV) types such as HPV16 and HPV18 is responsible for more than 5% of all human cancers worldwide. Despite the introduction of a prophylactic vaccine in 2006, HPV will continue to cause significant morbidity and mortality in the human population due to the long latency period between infection and disease, limited vaccine coverage, and type-restricted neutralizing immune responses. Therefore, further studies into the understanding of the biology of this virus group are warranted.

HPV are nonenveloped viruses harboring a circular double-stranded DNA genome of approximately 8,000 bp. They are highly tissue-specific and only replicate in keratinocytes of the skin and mucosa. Their life cycle begins by establishing infection in the basal cell of this stratified epithelia, gaining access through abrasions, wounds and microlesions. Once infection is established in the basal keratinocytes, the virus goes latent with a restricted viral replication and transcription program. When HPV harboring keratinocytes enter into the terminal differentiation program, the productive phase of the life cycle begins finally resulting in the generation of progeny virions in the uppermost layers of this stratified epithelium. This may result in the formation of skin, oral and genital warts. In rare cases of persistency, infection with high-risk HPV types can induce the development of tumors such as cervical, anogenital, and oropharyngeal squamous cell carcinoma.

While we do have a good understanding of the transformation processes at the mechanistic levels and the role viral oncoproteins play, we have an incomplete understanding of immediate early events of the viral life cycle. This is partially due to the complexity of the viral life cycle, the difficulty to generate infectious viruses and to infect primary keratinocytes in cell culture models. Our research interest is focused on these immediate early events. To this end, we have developed a number of surrogate reagents, assays, and more recently cell culture models to study binding, entry and trafficking of virions in immortalized and primary keratinocytes, respectively. This allowed us to uncover novel cellular pathways manipulated and exploited by the virus to achieve establishment of infection. By identifying cellular factors and pathways involved, we hope to identify novel prophylactic and therapeutic targets.

Late Intracellular trafficking of HPV virions – We have recently demonstrated that the minor capsid protein L2 traverses the endocytic membrane after acidification of endosomes and partial uncoating. This process requires the cellular chaperone cyclophilin B and a membrane-destabilizing domain at the L2 carboxyl terminus for uncoating and membrane penetration (Fig 1). The cytosolic portion of L2 then mediates interaction with transport factors such as retromer complexes for trafficking to the trans golgi network (TGN). Once arriving at the TGN, HPV requires nuclear envelope break down and mitosis for nuclear translocation. We recently demonstrated that transport vesicles harboring HPV dissociate from the TGN and are transported to the microtubule organizing center and further on to mitotic chromosomes. The transport is again mediated by the cytosolic domains of the L2 protein. We are currently investigating the role of microtubules and motor proteins in the late trafficking of HPV using live cell imaging, inhibitor studies, and knock out approaches.

One of the most striking observations we recently made was that HPV is delivered to the nucleus during mitosis residing in membrane-bound transport vesicles (Fig 2). Egress of viral genome from the transport vesicles occurs in early G1 phase. These are paradigm-shifting observations as it has been assumed that nuclear membrane-bound vesicles do not exist. Since we do not observe accumulation of vesicles in the nucleus, our data indirectly point to the existence of a quality control pathway that discards of membrane-bound vesicles ending up in the nucleus. We are currently exploring putative roles of nuclear lipases in this process using release of HPV genome from transport vesicles as biological read-out.

PML nuclear bodies and establishment of HPV infection – It is well established that HPV associated with PML nuclear bodies after infectious delivery and require PML protein for efficient transcription. We recently demonstrated that PML protein play a protective role and its absence results in the loss of incoming viral genome despite efficient nuclear delivery. We now found that PML protein is recruited to incoming viral genome and completely engulfs it before egress from the transport vesicle. Interestingly recruitment of another component of PML nuclear bodies, Sp100, which functions as HPV restriction factor, is specifically delayed to HPV-harboring PML nuclear bodies. We are currently exploring a role of these subnuclear structures in the early transcriptional regulation of incoming HPV genome and are trying to unravel the innate immune pathways present in the nucleus that are capable of sensing and degrading incoming HPV genome.

Immediate early events of the HPV life cycle – Until recently, primary keratinocytes, the natural target cells of HPV, could not be efficiently infected in vitro. Therefore, most studies were limited to the use of established immortalized cell lines harboring episomal HPV genomes. Based on the extensive knowledge gained in recent years regarding binding and internalization of HPV, we have now developed an infection model that allows efficient infection of primary keratinocytes. For this, we are exploiting the preferential binding of HPV virions to extracellular depositions by pre-binding virions to extracellular matrix derived from keratinocytes prior to addition of keratinocytes. HPV virions are generated using the 293TT packaging cell line alleviating the need for any viral factors other than the capsid proteins for virion production. This allows an extensive genetic manipulation of the viral genome. We are currently exploiting this model to further our understanding of temporal viral gene expression, genome replication and segregation, and the role of viral factors involved. The model will also be helpful to compare low and high risk viruses and to analyse the host response to viral infection without the for immortalization and selection.