Browsing by Author "Datla, Udaya Sree"
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- Harnessing Systems Bioengineering Approaches to Study Microbe-Microbe and Host-Microbe Interactions in Health and DiseaseDatla, Udaya Sree (Virginia Tech, 2024-03-22)The core of the dissertation lies in developing two novel systems bioengineering approaches, a synthetic Escherichia coli killer-prey microecology, and a combined infection-inflammation NET-array system, to investigate the role of the mechanochemical complexity of the microenvironment in driving the microbe-microbe and host-microbe interactions, respectively. Herein, the first part of the dissertation includes designing and engineering a synthetic E. coli killer-prey microecological system where we quantified the quorum-sensing mediated interactions between the engineered killer and prey E. coli bacterial strains plated on nutrient-rich media. In this work, we developed the plate assay followed by plasmid sequencing and computational modeling that emphasizes the concept of the constant evolution of species or acquired resistance in the prey E. coli, in the vicinity of the killer strain. We designed the microecological system such that the killer cells (dotted at the center of the plate) constitutively produce and secrete AHL quorum-sensing molecules into the microenvironment. AHL then diffuses into the prey cells (spread throughout the plate) and upregulates the expression of a protein that lyses the prey. Through time-lapse imaging on petri plates automated using a scanner, we recorded the "kill wave" that originates outside the killer colony and travels outward as the prey dies. We found that the prey population density surrounding the killer decreased in comparison to other locations on the plate far from the killer. However, some of the prey colonies evolve to be resistant to the effects of AHL secreted by the killer. These prey colonies resistant to the killer were then selected and confirmed by plasmid sequencing. Using this empirical data, we developed the first ecological model emphasizing the concept of the constant evolution of species, where the survival of the prey species is dependent on the location (distance from the killer) or the evolution of resistance. The importance of this work lies in the context of the evolution of antibiotic-resistant bacterial strains and in understanding the communication between the microbial consortia, such as in the gut microbiome. Further, the second part of the dissertation includes quantifying the interactions between immune cells (primary healthy human neutrophils) and motile Pseudomonas aeruginosa bacteria in an inflammation-rich microenvironment. Neutrophils, being the first responding immune cells to infection, defend by deploying various defense mechanisms either by phagocytosing and killing the pathogen intracellularly or through a suicidal mechanism of releasing their DNA to the extracellular space in the form of Neutrophil Extracellular Traps (NETs) to trap the invading pathogens. Although the release of NETs is originally considered a protective mechanism, it is shown to increase the inflammation levels in the host if unchecked, ultimately resulting in end-organ damage (especially lung and kidney damage), as with the severe cases of sepsis and COVID-19. In our work, we developed a combined infection-inflammation NET-array system integrated with a live imaging assay to quantify the spatiotemporal dynamics of NET release in response to P. aeruginosa infection in an inflammatory milieu at a single-cell resolution. Importantly, we found increased NET release to P. aeruginosa PAO1 when challenged with inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), but not leukotriene B4 (LTB4), compared to the infection alone. Our device platform is unique in that the nanoliter well-assisted individual neutrophil trapping enables us to quantify NET release with single-cell precision. Besides, incorporating confined side loops in the device helped us study the role of mechanical confinement on NET release, showing reduced NET release from neutrophils confined in the side loops compared to the relatively wider chambers of our microsystem. In summary, our work emphasizes the importance of studying the heterogeneity of NET release in host defense and inflammation. In the future, our system can be used for screening novel neutrophil-based immunotherapies and serve as a valuable research tool in precision medicine.
- Heparin-based hydrogel scaffolding alters the transcriptomic profile and increases the chemoresistance of MDA-MB-231 triple-negative breast cancer cellsMenon, Nidhi; Dang, Ha X.; Datla, Udaya Sree; Moarefian, Maryam; Lawrence, Christopher B.; Maher, Christopher A.; Jones, Caroline N. (2020-05-21)The tumor microenvironment plays a critical role in the proliferation and chemoresistance of cancer cells. Growth factors (GFs) are known to interact with the extracellular matrix (ECM) via heparin binding sites, and these associations influence cell behavior. In the present study, we demonstrate the ability to define signals presented by the scaffold by pre-mixing growth factors, such as epidermal growth factor, into the heparin-based (HP-B) hydrogel prior to gelation. In the 3D biomimetic microenvironment, breast cancer cells formed spheroids within 24 hours of initial seeding. Despite higher number of proliferating cells in 2D cultures, 3D spheroids exhibited a higher degree of chemoresistance after 72 hours. Further, our RNA sequencing results highlighted the phenotypic changes influenced by solid-phase GF presentation. Wnt/beta-catenin and TGF-beta signaling were upregulated in the cells grown in the hydrogel, while apoptosis, IL2-STAT5 and PI3K-AKT-mTOR signaling were downregulated. With emerging technologies for precision medicine in cancer, this nature of fine-tuning the microenvironment is paramount for cultivation and downstream characterization of primary cancer cells and rare circulating tumor cells (CTCs), and effective screening of chemotherapeutic agents.
- The spatiotemporal system dynamics of acquired resistance in an engineered microecologyDatla, Udaya Sree; Mather, William H.; Chen, Sheng; Shoultz, Isaac W.; Täuber, Uwe C.; Jones, Carolyn N.; Butzin, Nicholas C. (Nature Publishing Group, 2017-11-22)