Theses and Dissertations School of Medicinehttp://hdl.handle.net/10713/642024-03-22T14:36:10Z2024-03-22T14:36:10ZAltered Gene Expression Profiles and Immune Responses in a Murine Model of a Non-lethal Flame Burn with Pseudomonas aeruginosa InfectionKambouris, Adrienne Reneehttp://hdl.handle.net/10713/215672024-03-22T02:18:23Z2023-01-01T00:00:00ZAltered Gene Expression Profiles and Immune Responses in a Murine Model of a Non-lethal Flame Burn with Pseudomonas aeruginosa Infection
Kambouris, Adrienne Renee
Humanity has lived with fires for millennia, but combat, domestic use, and recent wildfires have increased the risk of burn injuries. Worldwide, over 100,000 deaths occur each year due to burns. If these patients survive the burn wound itself, the most common causes of death are multiorgan failure and sepsis, often caused by infection by Pseudomonas aeruginosa (PA). Utilizing a 10% total body surface area (TBSA) non-lethal flame burn model in mice, a superimposed infection of PA caused 100% mortality within 36 hours post-burn. This effect was transient, as infection 72 hours post-burn resulted in survival. The hypothesis was that this mortality could be linked to changes in gene expression that altered host-pathogen interaction. NanoString™, a system that allowed us to develop a custom panel of probes, was utilized to measure Mus musculus and PA gene transcripts simultaneously in each sample. Sampling from the blood, spleen, liver, and skin, gene expression in the burn and infection condition (B/I) was significantly different in each tissue when compared to mice that were burned alone, infected alone, and neither burned nor infected (Sham). The expression of the anti-inflammatory gene, Il10 is significantly increased over time in the spleen; administering anti-IL-10 antibodies delayed mortality by one day. While Arg1 and Nos2 gene expression were not significantly altered, administering arginine concurrently with PA restored survival in our mouse model, likely due to an inhibition of both PA motility and growth. We also hypothesized that burn-induced neutrophil dysfunction allowed for PA proliferation. Neutrophils isolated from the seroma of burned mice had a decreased ability to produce antibacterial reactive oxygen species (ROS) compared to neutrophils in the circulation of the same mice. Surprisingly, naïve neutrophils in the circulation of burned mice had a decreased ability to kill PA, possibly due to their premature ROS production induced by a burn-generated DAMP, HMGB1, present in the serum of burned but not Sham mice. In conclusion, a non-lethal burn injury is sufficient to induce multi-faceted changes in the murine immune system that results in an increased susceptibility to lethal PA superinfection.
University of Maryland, Baltimore School of Medicine. Ph.D. 2023.
2023-01-01T00:00:00ZPim kinase inhibitor enhances FLT3 inhibitor gilteritinib efficacy through GSK-3β activation and GSK-3β-mediated c-Myc and Mcl-1 proteasomal degradationLee, Jonellehttp://hdl.handle.net/10713/215662024-03-22T02:18:03Z2023-01-01T00:00:00ZPim kinase inhibitor enhances FLT3 inhibitor gilteritinib efficacy through GSK-3β activation and GSK-3β-mediated c-Myc and Mcl-1 proteasomal degradation
Lee, Jonelle
Acute myeloid leukemia (AML) with fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) has poor outcomes. FLT3-ITD drives constitutive and aberrant FLT3 signaling, activating STAT5 and upregulating the downstream oncogenic serine/threonine kinase Pim-1. FLT3 inhibitors have limited clinical efficacy. We previously showed that concurrent Pim and FLT3 inhibition increases apoptosis induction in FLT3-ITD-expressing cells through post-translational downregulation of Mcl-1. Here we further elucidate the mechanisms of action of this dual targeting strategy. Protein expression and turnover, cytotoxicity and apoptosis were measured in FLT3-ITD-expressing cell lines and AML blasts treated with FLT3 inhibitor gilteritinib and/or Pim inhibitors AZD1208 or TP-3654. Pim and FLT3 inhibitor co-treatment decreased c-Myc protein, prior to Mcl-1, increased turnover of both proteins, rescued by proteasome inhibition, dephosphorylated (activated) GSK-3β, and increased apoptosis and in vivo efficacy. GSK-3β inhibition prevented c-Myc and Mcl-1 downregulation and apoptosis. Pim and FLT3 inhibitor co-treatment of Ba/F3-ITD cells infected with T58A c-Myc or S159A Mcl-1 plasmids, preventing phosphorylation at these sites, did not downregulate these proteins, increase their turnover or induce apoptosis, consistent with GSK-3β activation and c-Myc T58 and Mcl-1 S159 phosphorylation as the mechanism of combination treatment. These data further support GSK-3β activation as a therapeutic strategy in FLT3-ITD AML.
University of Maryland, Baltimore School of Medicine. Ph.D. 2023.
2023-01-01T00:00:00ZRole of Social Determinants of Health on the HIV Testing and Treatment Cascade in NigeriaMohanty, Kareshmahttp://hdl.handle.net/10713/215652024-03-22T02:18:30Z2023-01-01T00:00:00ZRole of Social Determinants of Health on the HIV Testing and Treatment Cascade in Nigeria
Mohanty, Kareshma
Introduction:
The Joint United Nations Programme on HIV and AIDS proposed that to achieve epidemic control of HIV by 2025; 95% of all people living with HIV are aware of their status, 95% of people diagnosed with HIV receive sustained antiretroviral therapy (ART), and 95% of all people on ART are virally suppressed (VLS). The 2018 Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS) found that in Nigeria, while only 47% knew their status, 96% had received ART, and 81% had achieved VLS.
Social determinants of health (SDH), like wealth index (WI), have been shown to play a significant role in HIV in western countries, but the evidence has been limited and mixed in Nigeria. Identifying political, social, cultural, demographic, economic, and behavioral indicators of SDH, can better explain and address the disparities in the HIV epidemic, especially in the testing and treatment cascade, that are preventing the UNAIDS targets from being met in Nigeria.
Objective:
Examine the role of singular and composite indicators of SDH on the 95-95-95 targets: HIV testing, receipts of ART, and VLS in people living with HIV in Nigeria. Additionally, examine if wealth modifies the relationship between SDH indicators and the three 95 targets.
Methods:
Using the World Health Organization-SDH framework and Factor Analysis, I constructed composite indicators of SDH for Nigeria from various population-level survey data sources. Scores from the sub-indices and Global Terrorism Index were categorized as low, medium, and high, and individual or states were assigned one of these categories. Subsequently, I examined the association of the composite and singular SDH factors with HIV testing, receipt of ART, and achievement of VLS through survey-weighted multivariable logistic regression. Additionally, I examined the significance of the SDH indicators with the testing and treatment outcomes, by each of the wealth quintiles.
Results:
Out of the seven sub-indices constructed, only Access to Public Services, Crime & Conflict, Government Corruption, and Government Performance met the internal reliability criterion (Cronbach alpha > 0.7). Global Terrorism Index was constructed based on the prescribed methodology. When examining HIV testing, the first target in the 95-95-95 UNAIDS strategy, medium levels of Government Corruption, lower/medium Government Performance, and high Terrorism was associated with lower testing. Unemployment, living in rural areas, and married before 18 years of age were significantly associated with lower odds of HIV testing. For receipt of ART, second 95-95-95 target, low/medium treatment coverage was associated with lower odds of being on treatment. Younger age, male sex, being single, and living in rural areas were the singular factors associated with lower receipt of ART. Finally, for the third 95-95-95 target, only singular SDH, like lack of condom usage during sex, CD4 count (<500), and ethnic languages were associated with lower VLS. Wealth modified the relationship between the social determinants and HIV testing and treatment, but the role was weak. Wealth may increase the gap between the lowest and highest wealth index strata; HIV-related disparities experienced might be more pronounced between the two ends.
Conclusion:
Understanding and addressing structural determinants like political stability, terrorism, gender equality, accessibility to public services, and treatment facility coverage, rather than individual-level behavioral factors, could help Nigeria achieve the 95-95-95 targets.
University of Maryland, Baltimore School of Medicine, Ph.D. 2023.
2023-01-01T00:00:00ZImpact of Host and Parasite Factors on Gametocyte Production in Plasmodium falciparumVareta, Jimmy Amakwahttp://hdl.handle.net/10713/213542024-02-25T02:22:01Z2023-01-01T00:00:00ZImpact of Host and Parasite Factors on Gametocyte Production in Plasmodium falciparum
Vareta, Jimmy Amakwa
Stalled progress in reducing the malaria burden over the past few years suggests the need to develop new interventions to augment existing ones, including interventions aimed at interrupting gametocyte transmission from humans to the mosquito vector. To develop and effectively apply interventions that target gametocytes, there is a need to understand patterns of gametocytemia observed between individuals. Gametocytemia varies by host age, season, symptom status, antimalarial drugs use, and complexity of infection; however, the underlying mechanisms of this variation are not fully understood. Complexity of infection may modulate gametocytemia in P. falciparum; however, mechanisms of how clone composition influences gametocyte production are not clear. Addressing this gap requires a genotyping assay that can detect and estimate relative clone frequency of gametocytes and asexual parasites in infections.
The dissertation aims were two-fold: 1) To develop an amplicon sequencing assay to genotype P. falciparum mature gametocytes; and 2) To evaluate the impact of host and parasite factors and gametocyte production in P. falciparum infections.
We identified a polymorphic region of the pfs230 gene as a marker to distinguish P. falciparum mature gametocyte clones. When evaluating the impact of host and parasite factors on gametocyte production and gametocytemia, we found that more complex and high parasite density infections were more likely to produce and harbor gametocytes. The proportion of infections that produced gametocytes were similar between age-groups and between symptomatic and asymptomatic individuals, but children and asymptomatic individuals were more likely to harbor gametocytes than adults and symptomatic individuals, respectively. These findings suggest that complexity of infection and parasite density may increase gametocyte production, but additional factors such as host immunity and duration of infection may contribute to the presence or absence of gametocytes after initiation of gametocyte production. Coupled with the development of the gametocyte genotyping assay which will be an important tool for studies aimed at understanding dynamics of gametocyte production in polyclonal infections, understanding the impact of host and parasite factors on gametocyte production and gametocytemia will help explain variation in gametocytemia observed between individuals. This knowledge could inform development and effective deployment of transmission interrupting interventions.
University of Maryland, Baltimore, School of Medicine, Ph.D., 2023
2023-01-01T00:00:00Z