Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by deficiency of the protein dystrophin and affects approximately 1/3500 boys. Basic/translational studies of exercise effects in DMD have been conducted for decades, but with often contradictory results concerning benefit vs. detriment especially for cardiac muscle. However, these studies have been exclusively performed in a mouse model which does not fully recapitulate the DMD cardiac phenotype. Here we present the first known characterization of exercise and physical function in a new DMD mdx rat model that better mimics human DMD. DMD mdx rats (n=6) and healthy, sibling wild types (WT, n=9) were compared in this study. I performed a battery of functional and exercise tests  when the rats were at 14-15 weeks of age, including max treadmill endurance, volitional wheel running distance, forelimb grip strength, and in-vivo hindlimb force testing. Total work performed in treadmill endurance testing was lower for DMD mdx (2.6±0.3 Kpm) vs. WT (29.3±2.2 Kpm), p<0.001. 24-hr wheel running distance was lower for DMD mdx (702±65m) vs. WT (1038±66m), p<0.001. Forelimb grip strength was lower for DMD mdx (211±16g) vs. WT (318±13g), p<0.001. Finally, in electrically-stimulated in-vivo hindlimb force testing, both muscular endurance (% of initial force at 200-s) and peak torque (at 120Hz) were less in DMDmdx (55±2%, 0.33±0.02nM*m/g) vs. WT (69±2%, 0.45±0.030nM*m/g) p<0.01. Capacity for volitional and forced exercise is severely impaired in the novel DMD rat, congruent with limitations observed in functional muscular strength and endurance. Ongoing work is examining exercise adaptations and cardiac responses in this model which may better represent training responses in DMD patients and be useful for establishing exercise guidelines in this population.

The deinstitutionalization of massive psychiatric hospitals in the 1970s and 1980s improved the physical and social environment of psychiatric hospitals and aided in the transition away from prison-like hospitals. Still, there remains opportunities for growth if the psychiatry field aims to engage and provide patients with a fully therapeutic setting in psychiatric hospitals. This research explores the relationship between a patient’s social and physical experience in a psychiatric hospital and their engagement with mental health treatment after discharge. I analyze the physical environment of a psychiatric unit and explore mental health professionals’ views on guidelines for maintaining a therapeutic environment in these spaces. Using qualitative methodology, including ethnographic observations of psychiatric hospitals in the Seattle area, photographs, and interviews, I discuss the environmental factors of psychiatric rooms through the evaluation of room design and its effectiveness in creating a therapeutic environment. Preliminary findings point to a possible relationship between consent and a patient's receptivity to post-hospitalization treatment after being exposed to the psychiatric hospitalization environment. Additional results could indicate a negative relationship between a patient’s socio-physical experience in an inpatient psychiatric facility and their engagement in future treatment after discharge. These research findings will enable mental health providers to better understand the relationship of socio-physical aspects in psychiatric hospitals to the continuation of a patient’s treatment after discharge. This information will help providers improve upon these experiences and increase a patient’s receptivity to post-hospitalization treatment.

Nemaline Myopathy (NM) is a severe genetic muscle disorder defined by muscle weakness and the presence of nemaline rods (rod-shaped intracellular aggregates). This disease is associated with multiple clinical subtypes that result from pathogenic genetic variants across 12 different genes, including skeletal 𝛼-actin (ACTA1). NM-associate mutation H40Y impacts the ACTA1 monomer structure such that it disrupts polymerization. Without efficient and accurate polymerization, ACTA1 monomers form altered protofilaments which do not properly support the cross-bridge cycle and result in contractile dysfunction. The variation and complexity of NM pathology coupled with the rarity of this disease have served as significant barriers to the development of any treatments for NM. Here we show the effects of top performing therapeutic small molecules simulated in the presence of NM-associated mutation H40Y on the structural and mechanical properties of ACTA1. Using Molecular Dynamics simulation data, we have quantified differences between H40Y and wildtype ACTA1. Furthermore, we searched for and designed a target small molecule to fix mutant actin polymerization and mechanical instability. Our results demonstrate how our lead designed small molecule alters the dynamics of the H40Y ACTA1 pentamer when simulated docked in its intended binding pocket. We anticipate that our best small molecule candidate will be tested in vitro for its ability to impact actin polymerization in polymerization assays produced from induced pluripotent stem cells bearing the H40Y mutation. Furthermore, following successful in vitro validation the small molecule may be extensively studied as a potential novel therapy for NM.

Cardiomyopathy is currently the leading cause of death for patients with Duchenne muscular dystrophy (DMD), a severe neuromuscular disease affecting young boys. With no current cure, gene therapy is a promising solution, but supplementation with drug therapies is likely inevitable to fully address the pathology seen in older patients. The use of human-induced pluripotent stem cell (hiPSC) models for drug studies is beneficial due to the direct relevance to human physiology and the potential development of personalized care. Dystrophic hiPSC cardiomyocytes have been shown to exhibit calcium reuptake delays, higher resting calcium levels, and frequent arrythmias. The Mack Lab previously conducted a preliminary drug screen on healthy and DMD-affected cardiomyocytes and found that certain L-type calcium channel blockers (CCBs) indicated a cardioprotective effect. These drug compounds (namely Nitrendipine and Nimodipine) have been shown to alleviate cardiac fibrosis in patients through vasodilation. In this project, I am validating the beneficial aspects of the drug compounds. I initially hypothesized that treatment of DMD hiPSC cardiomyocytes with L-type CCBs will rescue resting calcium levels and normalize relaxation kinetics. To assess this, I cultured mature hiPSC cardiomyocytes on a Microelectrode Array (MEA) system capable of maintaining physiological conditions while measuring properties of cardiac electrophysiology. To enhance cellular maturity, I treated hiPSC cardiomyocytes with MicroRNA Maturation Cocktail (MiMaC) and cultured long-term prior to MEA assessment. Using the MEA, I have found that the QT interval for DMD hiPSC cardiomyocytes was significantly longer than isogenic controls. In current experiments, I am using this platform to validate the effect of L-type CCB compounds of interest in relation to DMD cardiomyopathy. The development of this novel platform may not only have broader implications for DMD drug discoveries and targeted therapies, but it can potentially serve as a powerful preclinical model for other neuromuscular disorders.

In the United States, 1.5 million individuals suffer a fracture due to bone disease each year. It is well documented that mechanical load affects bone development, but our understanding of the cellular mechanisms behind bone development under load is limited. Current human induced pluripotent stem cell (hiPSC) derived bone tissue models have more relevant human physiology compared to traditional animal models. However, there is a lack of dynamically loaded hiPSC bone tissue and diseased hiPSC bone tissue models in vitro. We propose a novel, three-dimensional bone tissue model as a platform for musculoskeletal disease modeling that allows for compressive loading that will enhance maturity as well as induce diseased bone phenotypes. We improved upon existing poly-L-lactide solvent cast scaffold techniques by incorporating a polyvinyl alcohol mold and an annealing step that increases the uniformity of the scaffolds and allows for higher throughput fabrication. Osteoblasts were derived from hiPSCs using established differentiation protocols and seeded into the 3D, porous, poly-L-lactide scaffold to generate in vitro bone tissue that generates significant extracellular calcium. We propose an arduino-powered, 3D-printed loading device that can apply physiologically relevant dynamic loads to the scaffold and hypothesize improved bone tissue maturity in comparison to 2D cultures and unloaded 3D scaffolds. By screening for markers of early bone development such as type I collagen, markers of later development such as osteocalcin, and assays for extracellular calcium, we can track the maturity and development of bone tissue. We expect that 3D bone growth with static loading will reveal diseased bone phenotypes such as decreased calcium deposition and immature bone, whereas dynamic loading will promote bone growth and lead to mature bone. Ultimately, this model will improve our ability to investigate the effects of mechanical loading in developing and diseased bone.