Yang Lab

The research lab of X. Frank Yang, PhD focuses on bacterial pathogenesis—how bacterial pathogens colonize the host, evade host immune response and cause diseases. The ultimate goals are to develop new diagnostic tools and vaccine to detect and prevent infections.

The primary focus of The Frank Yang Lab revolves around researching the pathogenesis of Lyme disease. As the leading vector-borne disease in the United States, Lyme disease poses a significant health concern. However, the understanding of how the causative agent, Borrelia burgdorferi, induces various manifestations such as Lyme arthritis, Lyme carditis, and neuroborreliosis remains limited. Presently, there is a notable absence of a human vaccine for preventing Lyme disease, and the diagnostic capabilities are suboptimal.

illustration of lyme disease host cycle. A mouse on the left has the di-nucleotide c-di-AMP. The tick on the left has the di-nucleotide c-di-GMP. There are arrows between the mouse and tick showing transmission and acquisition of lyme disease cycling between the two creatures.

One area of the Lyme disease research is to elucidate the strategies B. burgdorferi employs that allow the pathogen to survive in the mammalian host and the tick vector. The laboratory has identified two key regulatory networks (Hk2-Rrp2, Hk1-Rrp1) and two di-nucleotide secondary messengers (c-di-GMP, c-di-AMP), that are essential either for the pathogen to infect mice or to survive in the tick vector. These pathways control many differentially expressed genes, and are potential targets for vaccine candidate or for diagnosis development.

illustration of lyme disease infection from tick to mouse. The unfed tick nymph has the OspA protein. The infection moves to the mouse, who has OspC protein in early infection. After adaptive immunity, the infection becomes a persistent infection. The mouse with persistent infection has the VIsE proteins. YebC is the transcription factor between early and persistent infection. Another area of the Lyme disease research is to study the mechanism of immune evasion by B. burgdorferi for its persistent infection. Differential expression of VlsE that undergoes antigenic variation is a key immune evasion strategy employed by B. burgdorferi. vlsE expression increases concomitantly with downregulation of the major immunodominant surface lipoprotein OspC in response to host adaptive immune response activation. The laboratory discovered a key transcription factor, YebC, that regulates vlsE expression. This finding sets the foundation to study how the pathogen senses the immune pressure to activate the VlsE antigenic variation system and provides a potential therapeutic target to combat persistent Lyme disease.

In addition to Lyme disease, the Frank Yang Lab also works on identification of factors as potential candidates for diagnosis and vaccine development against Syphilis (one of the important sexual transmitted infections caused byTreponema pallidum) and Leptospirosis (a re-emerging zoonotic disease caused by Leptospira interrogans).

Research Funding

5R01, AI083640 (Yang) 6/2023-5/2028 
Regulatory Network of the Lyme Disease Pathogen

R01AI152235 (Yang, Sintim) 6/2020-5/2025
Targeting Cyclic Dinucleotide Signaling Pathways to Interrupt the Nature Cycle of Borrelia burgdorferi

R21, NIH-NIAID AI169333-01A1 (Yang) 5/2022– 4/2024
The Role of YebC in persistent infection of the Lyme disease pathogen

Steven & Alexandra Cohen Foundation (Yang, Sintim) 5/2020-4/2024
Development of Novel Therapeutic Compounds against Active and Persistent Borrelia burgdorferi

Recent Publications

Alazani F, Ranghunandanan S, Priya R, Yang XF*. 2023. The RpoN-RpoS regulatory pathway plays an important role in the blood-brain barrier transmigration of the Lyme disease pathogen. Infection and Immunity. 91(11):1-12, e0022723. doi: 10.1128/iai.00227-23.

Priya, R., Raghunandanan, S., Alanazi, F. and Yang XF*. 2023. Borrelia burgdorferic-di-AMP induces type I IFN response in macrophage through the activation of STING signaling pathway. The Journal of Immunology, 210, 241.207.

Zhang Y, Chen T, Raghunandanan S, Xiang X, Yang J, Liu Q, Edmondson DG, Norris S, Yang XF*, Lou Y*. 2020. YebC regulates variable surface antigen VlsE expression and is required for host immune evasion in Borrelia burgdorferi. PLOS pathogens. 16(10), e1008953. doi: 10.1371/journal.ppat.1008953.

Liu Q, Xu H, Zhang Y, Yang J, Du J, Zhou Y, Yang XF*, Lou Y*. 2020. Role of Hk2 in the enzootic cycle of Borrelia burgdorferi. Frontier Medicine. doi: 10.3389/fmed.2020.573648

Zhang JJ, Yang Y, Troxell B, He M, Carrasco S, Du J, Li H, Gomelsky M, Yang XF*. 2018. Dual Roles of c-di-GMP Binding Protein PlzA in the Regulation of Glycerol Uptake and Metabolism in Borrelia burgdorferi. Journal of Bacteriology. 200 (22) e00243-18; DOI: 10.1128/JB.00243-18

Zhang JJ, Hu WL, Yang YY, Picardeau M, Yan J, Yang XF*. 2018. The sigma factor σ54 is required for the long-term survival of Leptospira biflexia in water. Molecular Microbiology. 109(1): 63-77. PMID: 29633391; DOI: 10.1111/mmi.13967

View a full list of publications from the Yang lab

Faculty Research Team

X. Frank Yang, PhD

Professor of Microbiology & Immunology

Additional Research Team Members

Sajith Raghunandanan, PhD
Postdoc Fellow

Raj Priya, PhD
Postdoc Fellow

Gaofeng Lin, PhD
Research Scientist

Fuad Alazani
PhD Candidate

Elise Warren, BS
Research Technician