The proper function of the Breast Cancer susceptibility gene 1 (BRCA1) and its subsequent protein in the human body is vital to healthy individuals. The malfunction of BRCA1 due to a mutation is associated with an increased risk of breast or ovarian cancer of up to 80%. The key to understanding whether a mutation in BRCA1 will lead to higher risk of cancer is its location. Many of its interactions with other proteins take place in the central region of BRCA1. Currently, little is known about how mutations located in this region affect BRCA1 structure and function. The central region is where BRCA1 interacts with another tumor suppressor called PALB2 to perform DNA repair. The central region site studied in this project can be activated as a response to DNA damage, influencing BRCA1 and PALB2 interaction to generate a damage repair response. We show how activation of BRCA1 affects its structure and function on the molecular level. The accomplish this we created three mutations in the central region that mimic activation of BRCA1 to identify possible significant changes in protein-protein interactions using biochemistry and structural biology techniques like Isothermal titration calorimetry and circular dichroism.

   Alzheimer’s disease (AD) is a neurodegenerative disease resulting in dementia and memory impairment in patients. Research is immensely important as there are currently no treatments available to slow, prevent, or cure the damage inflicted upon individuals. The brain dysfunction in AD is marked by an increase in amyloid beta (Aβ), the protein responsible for plaque deposition in the brain. The severity of the cognitive deficits positively correlates with the load of Aβ. Prior research in animal models has pointed to Aβ causing synaptic disruption. A synapse is associated with information transfer inside the brain. Neuroscientists are trying to determine if the synapse disruption caused by Aβ leads to the cognitive dysfunction seen in AD. However, it is difficult it is to visualize individual neurons inside the hippocampus. In the present study, our aim was to understand the effect that Aβ has on synapses using an immunolabeling and tissue clearing technique in an AD transgenic mouse model. The 5xFAD mouse model utilized in this study rapidly develops Aβ pathology. This model mimics the pathophysiology of AD in humans. The mouse model used was also knock-in transgenic for Green Fluorescent Protein (GFP) on mature neurons. Using immunolabeling, GFP was tagged with antibodies, thus making neurons visible under the microscope. Antibodies were also used for Aβ in order to visualize the amount of Aβ protein and its location. Images of neurons were obtained in both FAD+/GFP+ and FAD-/GFP+ mice using a conventional staining method and a tissue clearing technique. We expected the tissue clearing technique, which clears lipids from the brain, to result in enhanced visualization of neurons but this was not the case. To quantify synapses, dendritic spines were counted on individual neurons in both groups of mice. Our results showed that Aβ accumulation in FAD+ mice correlates with a decreased number of dendritic spines signifying a decrease in synaptic density.

Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder that is currently ranked as the sixth leading cause of death in the United States. Those affected by the disease experience symptoms including but not limited to mental decline, memory loss, confusion, difficulty with language, and behavioral and mood changes.  One of the hallmarks of AD is inflammation that occurs both centrally in the brain and in the periphery. While inflammation is the natural response to activation of our immune system and is critical for our survival, neuroinflammation is heavily associated with AD pathology. Two main cellular mediators involved with the inflammatory response are members of the glial cell family, microglial cells and astrocytes. When chronic inflammation is uncontrolled, it can lead to harmful cell and tissue damage. The continuous presence of damaged neurons results in the constant activation of microglia and astrocytes. This generates a neuroinflammatory environment which is thought to promote neurodegeneration. Another process commonly up regulated in the brains of aging individuals is that of oxidative stress, which plays a major role in age-related neurodegeneration and cognitive decline. The process can occur due to dysfunction of the antioxidant system, causing the accumulation of reactive oxygen species (ROS) in the brain. One of the primary biological markers of AD is the aggregation of Amyloid beta (Abeta). Abeta itself has been shown to act as a pro-inflammatory agent, promoting the activation of many inflammatory components. The accumulation of Abeta aggregates is thought to be exacerbated by essential biometal ions such as zinc and copper. Dr. Kayla Green’s lab in the TCU Chemistry Department has successfully created compounds that can simultaneously chelate metal ions and act as a powerful antioxidant. They have developed a family of compounds all consisting of N-heterocyclic amines that in turn, have the capacity to perform radical scavenging and metal ion capture. For the experimental design, BV2 neuronal cells were treated with either H202 or LPS for 16 hours. Following treatment, MTT assays were performed to measure cell viability. Once a treatment concentration was discovered that significantly decreased cell viability, varying concentrations of the N-heterocyclic amine were added to test for a recovery in overall cell viability.

Exploring the Effects of Early Life Stage Nitrate Exposure on Sexual Development and Adult Reproduction

Nitrate is a ubiquitous environmental contaminant that enters aquatic ecosystems as runoff from agricultural fertilizers, human and animal waste, and industrial processes. Previous animal studies indicate that at sublethal concentrations, nitrate acts as an anti-androgen in adult male vertebrates. However, a recent study using developing fathead minnows (Pimephales promelas) found that exposure to nitrate was correlated with increased androgen concentrations. This study sought to reconcile these conflicting results by exploring the impacts of environmentally realistic, early life stage nitrate exposure on male sexual development and adult reproduction. The main objective of this study was to identify the potential endocrine disrupting effects of nitrate across multiple levels of biological organization in male fathead minnows. Larvae less than 1 day post hatch were divided into three groups: 1) control, 2) low nitrate (50 mg/L NO3), 3) high nitrate (100 mg/L NO3) and exposed for 35 days. Gonadal gene expression of sex-steroid related genes was assessed in a subset of fish immediately following exposure. The remaining fish in each exposure group were raised in clean water until sexual maturity (115 dph) and then subjected to a 21-day breeding study, after which morphological measurements and male secondary sex characteristics were assessed. Gene expression analysis revealed that male fish in the high nitrate group had significantly decreased expression of a key enzyme in the sex steroid synthesis pathway than that of the control males. Breeding pairs in the high nitrate group also had a significant reduction in average clutch size. However, when these results are taken in conjunction with the analyses of the other target genes, breeding study endpoints, and morphological measurements, the exact effects of nitrate on the processes of sexual development and adult reproduction remain unclear.

Introduction: The purpose of this research was to determine differences in the effects of the sex hormone estrogen between the two genders on the endothelial function in vivo. Method: There was a total of forty-six college students from a liberal college in the South recruited. The forty-six students were twenty males and twenty-six females, who were divided into three groups: 20 males, 8 females (not taking any form of birth control) and 13 females (taking oral contraceptives). The participants were invited to complete a TCU approved IRB consent form and medical history questionnaire. Upon completion, the participants provided passive drool saliva for biomarker and sex hormone measurement and FMD for brachial artery flow and shear stress measurements. Results: Findings reveals that the mean age for males was 27.81 years and the mean age for females was 24.81 years. This data was found to be not significant (p = 0.0586). The BMI for males was 26.3 ± 3.59 kg/m2 and the BMI for females was 22.8 ± 2.36 kg/m2, found to be significant (p = 0.0003). 17-beta estradiol level was measured during follicular phase. There was no significant difference between men, women, and women on birth control. However, there was significant difference between male and female regarding nitrate production during the follicular phase (p = 0.0461). When comparing the post flow shear rate between women on birth control and women not on birth control, there was an increase in the shear velocity. Even though there was no significant change in sheer rate and FMD in the women on birth control, a trend toward an increase of both measures was noticed. Conclusion: There was found to be no significant difference in the effects of estrogen between men and women. Further research should be conducted to further specify the differences between women on contraceptives and men.