Alzheimer’s Disease (AD) is the 6th leading cause of death in the US. More than 44 million people worldwide, including 5.7 million Americans, are living with this neurodegenerative disease, and those numbers continue to climb. One of the features associated with AD is a disrupted sleep/wake cycle. Sleep is essential for many psychological and biological functions. A reported 35.3% of adults get less than the minimum 7 hours of sleep per night recommended by the National Sleep Foundation. Evidence suggests a bidirectional relationship between sleep loss and AD. Previous research indicates that disruptions in sleep often precede symptoms of AD such as cognitive impairments and memory loss. Chronic sleep loss has been associated with increased amyloid-beta and proinflammatory cytokines in the brain. Extended release of these proinflammatory cytokines can lead to increases in amyloid beta in the brain, which aggregates to form plaques that disrupt neuronal communication, a hallmark of AD. The aim of the present study was to elucidate the interaction between chronic sleep restriction, inflammation, and AD pathology in C57BL6/J mice. Our lab has previously demonstrated that mice administered seven consecutive days of LPS, a bacterial mimetic, exhibit increases in amyloid beta and proinflammatory cytokines in the brain, as well as cognitive deficits. Furthermore, research from our lab has shown that stress can exacerbate the effects of LPS. Healthy C57BL6/J adult mice were subjected to the multiple platform method of sleep disruption for 10 hours per day for 6 weeks. After receiving 7 consecutive days of either LPS or saline injections, animals were subjected to contextual fear conditioning to assess cognitive functioning, and hippocampal amyloid beta levels were quantified. While 7 days of LPS administration did not increase amyloid beta or cognitive deficits in contextual fear conditioning, chronic sleep restriction was associated with deficits in contextual fear acquisition and increased levels of hippocampal amyloid beta compared to control groups. Therefore, chronic sleep loss may have detrimental effects to cognitive function through increasing amyloid beta levels in the hippocampus. Given the large percentage of adults reporting getting less than the minimum recommended 7 hours of sleep per night, combined with the alarming climb in rates of AD and a growing body of work suggesting a link between these trends, investigating the detrimental effects of not getting enough sleep is an essential area of study.

Stress has been linked to altering acute and long-term inflammatory responses. Stress has been shown to activate inflammatory responses, specifically microglial activation in the brain. While acute inflammation is one of the first responses to fighting disease and infection, prolonged inflammation has been associated with neurogenerative disease such as Alzheimer’s disease. Stress at critical periods of development, known as early life stress (ELS) has been linked to chronic dysregulation of the hypothalamic-pituitary adrenal (HPA) axis, depression and alterations to microglial cells. The goal of this study is to investigate the effect of stress in mice during early development through maternal stress during pregnancy and the impact on neuroinflammation in adult offspring. In utero, offspring are vulnerable to the harmful effects of pro-inflammatory cytokines due to stress experienced by adult mice, following an ELS timeline. Three conditions were utilized: (1) mice undergoing stress during the entire pre-natal period and with the early post-natal period, (2) mice undergoing stress during the early postnatal period, and (3) mice undergoing no additional stress at any point. For mice in the combination-stress condition, there was an immunosuppressive effect through downregulation of pro-inflammatory cytokines. These data support existing publications that indicate an immunosuppressive role of prenatal stress, leaving the host less protected against chronic disease.

Males and females differ with regard to their immune response to a pathogen. Previous studies have observed males having reduced pathogen resistance. This suggests that they may be responding to pathogens differently. However, few studies have compared male and female immune responses following pathogen exposure. The purpose of this study was to examine sex-based differences in pathogen resistance and immune responses following exposure to a pathogen in adult fathead minnows (Pimephales promelas). To accomplish this, fish were bacterially infected with Yersinia ruckeri and the immune system’s ability to respond was monitored. Additionally, genes that are known to turn on during the immune response initiation were measured quantitatively providing insight into the molecular effect in minnows. At the whole organism level, male fish were less able to survive pathogen infection relative to female fish. At the tissue level, both male and female pathogen injected fish had decreased hematocrit percentages compared to the fish injected with a saline solution but did not differ from each other. At the molecular level, increased gene expression of interleukin 1β was seen in pathogen-injected males compared to pathogen-injected females and both sham-injected sexes indicating that pathogen-injected males mounted a larger inflammatory response at the molecular level. Taken together, this evidence suggests that the increased mortality observed among males earlier in the exposure to the pathogen may be due to the upregulated inflammatory response rather than the effects of the pathogen itself.

Alzheimer’s disease (AD) is a very prevalent neurodegenerative disorder and is the 6th leading cause of death in the United States. Alzheimer’s disease (AD) is characterized by widely distributed amyloid plaques and neurofibrillary tangles, and is clinically associated with a progressive decline in memory and other cognitive functions. The major protein component of neuritic plaques is amyloid beta peptide. Several pieces of evidence have indicated that amyloid beta accumulates to form oligomeric states in the AD brain and cause the cognitive dysfunction commonly seen in patients. While a decrease in cognitive function is considered a hallmark of the disease, AD patients also exhibit decreased motor abilities and difficulties learning new motor tasks. Our lab’s previous investigations found voluntary running to decreased amyloid beta burden in C57/BL6 mice. The present experiment seeks to further explore the mechanism through which exercise induced amyloid beta clearance occurs. Previous studies have pointed to the function of the glymphatic system in the clearance of amyloid beta. The level and distribution of aquaporin 4 (AQP4) in the vascular endfeet of astrocytes is crucial to the normal function of the glymphatic system. Our experiment sought to determine a more detailed analysis of the role of AQP4 in the glymphatic clearance of amyloid beta. Using TGN-020, a selective AQP4 antagonist, we hope to further determine the importance of glymphatic clearance of amyloid beta in C57/BL6 mice through exercise. We hypothesize that mice receiving intraperitoneal TGN injections, thus blocking the function of AQP4, will experience decreased glymphatic clearance of amyloid beta. Understanding the process of amyoid beta clearance can aid in treatments for both the pathological and clinical affects associated with AD.

Bacillus anthracis is a Gram-positive bacterium that causes anthrax in humans. It is a significant microorganism in that many proteins important to virulence or pathogenesis are highly conserved in many other pathogenic bacteria. Our lab has previously identified the protein ClpX in Bacillus anthracis as metabolically significant in antibiotic resistance. Specifically, B. anthracis lacking the ClpX gene (ΔClpX) are significantly more susceptible to antibiotics that target the bacterial cell wall such as penicillin than the wild type. ClpX has multiple functions; primarily it interacts with ClpP to form a proteolytic complex that degrades dysfunctional or obsolete proteins. ClpX also has an independent chaperone function, moving proteins around the cell. This project has focused on determining if the pathway of decreased antibiotic resistance in mutant B. anthracis is dependent on ClpX interactions with ClpP, or if ClpX can function independently. To test this, a point mutation (I265E) was made in the ClpX gene at the site that has been previously identified as the site of interaction between ClpX and ClpP in Staphylococcus aureus. The ClpX genes in B. anthracis and S. aureus exhibit a high degree of conservation particularly in this region, and it is expected that this site will also be critical for ClpX and ClpP interaction in B. anthracis. The mutated ClpX gene (I265E) has been confirmed with sequencing and has been transformed as an inducible expression plasmit into the ΔClpX B. anthracis strain. The next step is to perfom growth assays in antibiotics such as penicillin to ascertain if the mutated expression vector can restore antibiotic resistance to ΔClpX.