Over the past decade, we have seen major forest loss due to events like deforestation and tree die off. Previous studies have examined ways in which the distribution of plant types and how they function impact local and global climate. Local climate can be impacted because plants alter fluxes of water, energy, and momentum between the land surface and the atmosphere. Global climate can be impacted because local changes influence atmospheric response in clouds, humidity, and gradients in energy which drive changes in circulation. This project aims to identify if observed forest loss has a measurable effect on the noisy climate system. We have compiled spatial data of actual forest loss derived from satellite observations and test the climate impact of forest loss in simulation experiments using an Earth system model. We will assess differences between simulations with and without forest loss to identify how forest loss impacted the atmosphere and surface climate over land. We use the identified impacts as hypotheses for the expected climate response to forest loss and will subsequently analyze if these patterns can be seen in observed environmental conditions following forest loss. We expect to see some effect in the climate due to the observed forest loss. This project serves to advance our understanding of the effect of forest loss on global climate, atmospheric circulation, and energy balance, and thus will help to coordinate efforts to mitigate climate change by identifying potential unwanted impacts of forest change due to human actions.

Hypertrophic cardiomyopathy is a disease affecting millions of people worldwide, characterized by thickened heart tissue, which makes pumping difficult for the heart. Since the restructuring of the heart is influenced by remodeling at the cellular level, the overall goal of the project is to investigate the mechanics of how cells sense tension in their environment and its relationship to regulating cell remodeling. The direction in which sarcomeres, the basic contractile unit in the heart, are added influences the shape of the cells and consequently the shape of the overall heart. To study this relationship, it is necessary to visualize the sarcomeres for correlating acquired tension data from FRET sensors. By attaching a fluorophore to a sarcomeric protein such as alpha-actinin, it is possible to visualize sarcomeres using fluorescent microscopy. For this project, I developed a blue fluorescent protein (BFP)-tagged alpha-actinin plasmid through molecular cloning techniques. I used restriction enzymes and PCR to isolate and amplify the genes of interest from a different plasmid, then used Gibson Assembly to insert the genes into a plasmid containing ampicillin resistance to construct the final BPF-tagged alpha-actinin plasmid. Preliminary results showed successful expression of the transiently transfected BFP construct in cardiomyocytes. The next steps are to optimize the transfection for higher efficiency, adapt an existing data analysis pipeline for analyzing sarcomere dynamics, and develop a set of parameters for efficient image acquisition. Many existing therapies for hypertrophic cardiomyopathy only address symptoms but do not solve the underlying issue of systolic dysfunction. Rather than taking a genetic or biochemical approach, which can be difficult to develop, this research project focuses on the mechanical interactions in the heart and studying the contractile forces may yield more insight into this disease and build the informational foundation for developing future therapies to prevent or treat hypertrophic cardiomyopathy.

Cardiomyopathies are diseases of the heart characterized by structurally and functionally abnormal cardiac tissue and can be caused by non-genetic or genetic causes. Genetic cardiomyopathies are the most common genetic cardiac condition, affecting 1 in 250 to 500. The two most common types of genetic cardiomyopathies are hypertrophic (HCM) and dilated (DCM). HCM is characterized by a thickening of the heart muscle. This thickening can lead to a blockage in the blood flow and cardiac relaxation abnormalities. DCM is pathologized by a weakening in the cardiac muscle, leading to a lengthening and thinning in the muscle. My research focuses on determining human specific mechanisms of DCM and HCM, specifically on determining the early developmental phenotypes of the cells that lead to downstream pathologies. I particularly emphasize how changes in sarcomere function lead to HCM and DCM using human induced pluripotent stem cell cardiomyocytes (hiPSC-CM). We have shown that sarcomeric mutations alter the amount of tension integrated over time (TTI) and those variations in TTI are predictive of HCM and DCM. I am generating two mutant hiPSC-CM lines, L48Q and I61Q, using CRISPR/Cas9. These mutations are both in the sarcomere, more specifically in cardiac troponin C (cTnC). They alter the calcium binding properties of cTnC. I have optimized the polymerase chain reactions in order to make the sequencing data clean for validation. I have generated the I61Q line and am working on the L48Q line. After validating the lines, I will differentiate them to cardiomyocytes in order to study the cellular mechanisms involved. I will then use IonOptix to test early vs. late calcium transience, cell contractility, and cell size. There are currently no treatments that address the contractile abnormalities present in HCM or DCM. My research will allow for greater understanding of these mechanisms which will inform potential therapies.

Traumatic brain injuries (TBIs) are a major cause of disability among war veterans, leading to behavioral dysfunction and post-concussive symptoms such as depression, anxiety, pain, and substance abuse. These symptoms are thought to be caused by neural inflammation combined with a malfunctioning autonomic nervous system following injury, called dysautonomia. Dysautonomia leads to changes in heart and respiratory rate, increased fatigue, and has been shown to be able to predict future behavioral outcomes such as depression. Vagal nerve stimulation (VNS) is currently being examined as a treatment for blast trauma, as the vagus nerve helps regulate the autonomic nervous system. I predict that VNS following blast exposures will reduce the neural inflammation and severity of dysautonomia following blast TBIs, in turn lessening the chronic behavioral dysfunction that normally occurs after blasts. To examine the effects of VNS on TBIs, I looked at both vital signs and behavioral dysfunction immediately and chronically following the blast. A shock tube that generates clinically relevant overpressure waves was utilized to simulate chronic (3x blast exposures (or sham exposure)) in 11-week-old C57BL/6J mice (n=5-6 per group, from two cohorts of mice). In addition to analyzing cytokine expression to determine inflammation and vital signs, several behavioral assays were run, including: operant conditioning, t-maze, y-maze, acoustic startle, and photophobia, to examine both biological and behavioral changes following blast and VNS treatment. Thus far it appears likely that the VNS treatment has lessened the severity of multiple measures of dysfunction, including pain, startle sensitization, and inflammation. This demonstrates that VNS could be a potential therapeutic for blast TBIs but further research, including running more mice to obtain a larger sample size, is necessary to draw more conclusions.

Blast exposure via detonation of explosives is a major source of trauma for service members, Veterans, and civilian bystanders, resulting in mild traumatic brain injury, post-traumatic stress disorder, and chronic pain. The combination of these effects characterizes the polytrauma clinical triad and is a risk factor for increased substance use and substance use disorder (SUD). Exposure to polytrauma can result in disparate symptom trajectories. Research focused on understanding how distinct symptom trajectories map onto substance preference and SUD risk is the focus of my project. In order to understand the interactions between polytrauma and SUD risk, I use a rodent model that utilizes custom, in-house-built polysubstance self-administration chambers to measure water, alcohol, and fentanyl intake. Two types of tracking are used to monitor drinking: Radio Frequency Identification (RFID) tracking and the volumetric drinking monitor. With these two tracking types combined, we can see which mouse drinks what liquid for what period of time. For this project, I used C57Bl/6 male and female mice aged 9 weeks on arrival. These mice were then single or group-housed in the RFID cages for one week to monitor drinking patterns. Previously, I have tested 48 mice, and found that when one (fentanyl or alcohol) substance was available, mice that were single-housed drank more substance than mice that were group housed. To continue this project, I plan to test fentanyl and alcohol in the same cage, which can give us valuable insight into substance preference and polysubstance use, making it more representative of the human experience, as many people consume multiple drugs at the same time. I also plan to look into sex differences and see how that could alter substance use. These factors combined will give valuable insight into classifying substance use that can lead to more optimized treatment for Veterans with polytrauma.