Diets high in fat and sugar have increasingly adverse effects with increasing age because of generally decreasing activity and energy needs. This nutritional overload results in an increase in body fat mass and an increase in risk for metabolic and cardiovascular disease and possibly other chronic diseases such as cancer. However, the role of fat mass in age-related pathology and survival over an extended period of time is controversial. To address this issue, C57BL/6 mice, 18 months of age, were started on a high caloric (HC) diet consisting of balanced protein, lard, and sucrose. A second cohort was maintained on a standard rodent caloric (RC) diet consisting of balanced protein, wheat, corn, and soybean oil. Fat mass was measured by quantitative magnetic resonance imaging (QMRI) monthly for 10 months (28 months of age) at which time mice were evaluated for physiological performance, and tissues collected for geropathology. Both diet groups started with an average 5 percent fat mass. Fat mass increased to 15 percent in the HC diet group over the next 3-5 months, then gradually decreased to 9 percent after 10 months on the diet. Fat mass gradually decreased to 3 percent in the RC diet group over 10 months. Mice fed the RC diet had increased paw grip strength and were able to stay on a rotating rod longer than mice fed the HC diet, but there was no difference in survival between the two diet cohorts over the 10-month trial period. These preliminary observations suggest that percent body fat mass generated by a diet high in animal fat and table sugar may be associated with unhealthy aging, but not survival. This provides rationale for subsequent investigations into the pathological consequences of high caloric diets with increasing age.

A 2019 study by Lobas, et al. demonstrated that a circularly permuted form of Green Fluorescent Protein (GFP) can be created such that it only fluoresces when bound to adenosine 5’ triphosphate (ATP), thereby acting as an observable ATP sensor. The primary source of ATP production in cells is in the mitochondria, and loss of mitochondrial function is considered a hallmark of aging. Because ATP additionally reflects the energetic availability of tissue in multicellular animals, it is of interest to study how ATP levels change in an organism throughout aging and in response to environmental stressors. This study uses a novel plasmid construct that has been optimized to express the fluorescent ATP sensor in the nematode C. elegans. These nematodes are visualized using our fluorescent imaging robot to measure ATP levels throughout the whole lifetime of the worms in order to determine if cellular ATP levels serve as an aging biomarker. The first construct uses whole body expression of the ATP sensor, which is expected to show varying levels of ATP-reporting fluorescence throughout the life of each animal before darkening in response to age-induced paralysis and death. Subsequent studies employ different promoters in the plasmid to create tissue-specific fluorescence. This allows for a wide combination of experiments that test the effect of environmental, temporal, and genetic factors on specific tissue ATP levels and longevity in C. elegans. For example, expressing the ATP sensor in hepatocytes in organisms under cyanide conditions indicates the energetic response of these cells to toxin. Results from these follow-up studies indicate how cellular energy affects organisms’ lifespans and the ability to respond to stressors, as well as the role that varying biochemical pathways play in maintaining energetic homeostasis during aging.

More than 1 in 5,000 individuals are born with genetic mutations leading to severe mitochondrial diseases. A better understanding of the pathophysiology of disease progression could potentially lead to the discovery of novel interventions to treat these disheartening diseases. We are using a mouse strain that is deficient in the complex I subunit of the Electron Transport Chain (NDUFS4) as a model of mitochondrial disease. The neurometabolic disease known as Leigh syndrome is most often caused by mutations of proteins in the Electron Transport Chain and leads to severe mitochondrial dysfunction. Similar to patients with this disease, these mice exhibit symptoms including retarded growth, neuroinflammation, and loss of motor activity eventually leading to premature death. Our lab recently discovered that rapamycin, an FDA-approved inhibitor of the Mechanistic Target of Rapamycin (mTOR), delays disease progression and drastically increases the survival of these mice. By inhibiting both mTOR complex I and 2, rapamycin deactivates the Protein Kinase C (PKC) pathway. By doing so, inflammation is reduced due to the deactivation of the innate immune response in these mice. Thus, these mechanistic advances suggest targeting the PKC pathway may be beneficial in the discovery of new disease interventions.

Abnormal activity in the extended face processing system has been implicated in face processing challenges in autism spectrum disorder (ASD). However, the impact of comorbid attention deficit hyperactivity disorder in individuals with ASD (ASD-ADHD) on social impairment and the neural substrates underlying face processing has not been investigated. To address this, we conducted an fMRI study of emotional face processing in participants with ASD-ADHD, ADHD and significant sensory processing challenges (ADHD), ASD, and typically developing children (TD). After excluding for motion, 16 children with ASD (Age M (SD) = 9.57 (0.06)), 16 children with ASD-ADHD (Age M (SD) = 10.08 (0.07)), 20 ADHD (Age M (SD) = 9.46 (0.06) and 40 TD controls (M (SD) = 10.04 (0.06)) were included. Social functioning between autism groups were compared using the Autism Diagnostic Interview-Revised (ADI-R). MR data were collected on a 3T Philips Achieva system. For the fMRI task, 54 volumes of high resolution data (2.3mm3) were collected. Participants were shown blocks of rapidly-presented (150 ms) fearful faces, houses and scrambled images. fMRI data were processed in FSL using standard processing methods. We tested group differences in the contrasts faces > houses and faces > scramble. The ASD participants were rated significantly higher than the ASD-ADHD group on the ADI-R social domain (ASD M=17.88, SD=6.18, ASD-ADHD M=12.33, SD=6.29, p<0.05). Children with ASD-ADHD exhibited reduced left amygdala (p = .025) and left fusiform (p = .03) activity compared to children with ADHD for faces > scramble contrast. However, activation in these areas did not significantly differ between the ADHD and ASD groups. These preliminary results indicate significantly altered brain activation during face processing in children with comorbid ASD and ADHD when compared to children with ASD alone, suggesting a possible additive effect of comorbidity on social difficulties.

Alzheimer’s disease (AD) is the most common cause of dementia. However, despite its wide prevalence and gravitas, the cause, molecular mechanism, and pathogenesis of AD are still not well understood. Prior studies indicate the formation and accumulation of amyloid-beta proteins may play a crucial role in the pathology of the disease. Furthermore, for a long time, investigators suspected that microbes may either directly or indirectly induce AD, characterizing AD’s pathology with an antimicrobial response. Some investigators found links between AD and Herpesviridae, specifically HSV-1 that’s highly prevalent in population, but have yet to find the exact relationship between AD and Herpes Simplex Virus (HSV-1). HSV-1 encodes an alkaline nuclease (UL12.5) known to cause degradation of the mitochondrial genome. We hypothesize that UL12.5 activity in the brain may inhibit amyloid-beta protein aggregation and predispose an individual to AD neuropathology. Here, we aim to control the amyloid-beta protein aggregation using a degron attached UL12.5, which will be induced by the plant hormone auxin through a molecular signaling pathway known as auxin-inducible degron. We have engineered an auxin UL12.5-degron construct in order to precisely control the temporal and cell type expression of UL12.5 in Caenorhabditis elegans (C.elegans). This construct was microinjected into the worms and by using auxin, and we controlled the expression of UL12.5 and tested its effects on amyloid-beta and Huntington protein aggregation. Ultimately, we aimed to elucidate the relationship between HSV-1 infection, UL12.5 expression, and neurodegenerative disease which may form the basis of novel treatments.

Alzheimer’s Disease (AD) is a neurodegenerative disorder and is the major root cause of dementia. The most common AD cases are classified as sporadic AD, which means there are no known genetic or other underlying causes. Therefore, improving our understanding of the etiological factors of AD is highly important. Recent studies have illustrated that infection with Herpes Simplex Virus 1 (HSV1) is associated with AD, however this link has only recently been demonstrated and not yet fully understood. It has been shown that HSV-associated transcripts are enriched in patients with AD: Transcription Factor EB (TFEB), Integral Membrane Protein 2B (ITM2B) and ATRX chromatin remodeler (ATRX). Our goal is to further validate the link between TFEB, ITM2B, and ATRX expression and AD in clinical samples as well as experimental animals. We aim to develop a highly sensitive and quantitative assay utilizing quantitative real-time Polymerase Chain Reaction (qPCR) to investigate expression of TFEB, ITM2B and ATRX transcripts. We are currently in the preliminary stages of verifying our qPCR assay’s precision in quantifying target RNA expression by producing standard curves from recombinant DNA fragments as well as quantifying cDNA transcript samples extracted from human and mouse kidney cells. Through our future work with experimental animals, we seek to improve our mechanistic understanding of the association between HSV infection, HSV-associated transcripts, and AD.

Knock out of Ndufs4, a gene that encodes a nuclear-encoded subunit of complex 1, models neurological mitochondrial disease in mice. Ndufs4^-/- mice are shorter lived, show fur loss around 21 days of age, and begin to show neurological symptoms around day 35. Acarbose is a FDA-approved anti-diabetic drug used to manage post-prandial glucose spikes. Administration of acarbose increases lifespan in Ndufs4^-/- mice and delays the onset of neurological symptoms. Importantly, acarbose does not appear to restore mitochondrial respiration; rather it decreases protein acetylation in the mitochondria of Ndufs4^-/- mice and restores the NAD+ /NADH ratio in the brain. Due to this observation, we wanted to look into how Ndufs4^-/-Sirt3^-/- mice responded to acarbose treatment because Sirt3 is a NAD-dependent deacetylase responsible for the deacetylation of proteins in the mitochondria. To test this, we crossed Ndufs4^+/- mice into a Sirt3^-/- strain of mice to determine whether Sirt3 is necessary to extend lifespan in response to acarbose. We set up 4 experimental groups consisting of Sirt3^+/+Ndufs4^-/- controls, Sirt3^-/-Ndufs4^-/- controls, Sirt3^+/+Ndufs4^-/- on continual 0.1% acarbose chow from day 21, and Sirt3^-/-Ndufs4^-/- on continual 0.1% acarbose chow from day 21. All mice were housed with companion mice that were heterozygous for the Ndufs4 gene to help with thermal regulation and prevent premature death. Mice were monitored and weighed daily and fed bi-weekly with 0.1% acarbose chow. Knock out of Sirt3 did not affect lifespan in Ndufs4^-/- mice. Furthermore, we measured extended lifespan in the mice treated with acarbose in both the Sirt3^+/+ and Sirt3^-/- genotypes indicating that Sirt3 is not required for lifespan extension from acarbose in this disease model. We are planning to collect brains from Ndufs4^-/- Sirt3^-/- animals to determine whether acarbose reduces acetylation in the mitochondria through a different mechanism, not the upregulation of Sirt3 deacetylase.