Prostate cancer (PCa) bone metastases have been reported in ~90% of patients with advanced disease. Bone metastases disrupt tissue homeostasis and weaken the skeleton, resulting in an increased risk of bone fractures and morbidity. Specifically, PCa cells disrupt the crosstalk between critical cells within the tumor/bone microenvironment (osteoblasts, osteoclasts, and immune cells), and utilize this effector-rich environment for cancer survival and growth. Therefore, a key therapeutic objective in malignant skeletal disease management is to eliminate tumors while restoring bone homeostasis. Current treatments include palliative radiotherapy, chemotherapy, or anti-RANK treatments, all of which have considerable side effects such as osteonecrosis of the jaw or enhanced tumor invasion. There remains a critical gap in therapies than can reduce tumor burden and simultaneously restore bone homeostasis. To address this gap, our work explores emerging gene therapy approaches for treating skeletal malignancies by utilizing multifunctional cytokine-based agents that can simultaneously combat tumor growth and promote bone regeneration.<div><br></div><div>We hypothesize that rationally designed cytokine-based gene therapies that can be secreted from skeletal muscle and targeted to the bone/tumor microenvironment, could effectively reduce tumor growth and restore bone cell homeostasis. To test this hypothesis, we adopted two strategies: 1) a second-generation targeted IL-27 cytokine, and 2) a de novodesign of a cytokine-like therapeutic agent (Propeptide) that includes anti-tumorigenic and pro-osteogenic domains. Both strategies share modules with overlapping therapeutic functions, rendering them complementary in their therapeutic application. In this work, we examined the proof of principle for propeptide gene therapy in muscle cells (in vitro models) and assessed the therapeutic efficacy of our cytokine-based biologics in reducing prostate tumor growth and rebalancing bone cell proliferation and differentiation. Our studies resulted in a propeptide construct representative of a cytokine structure comprised of a bundle of helices that we were able to express in cells. Additionally, our work demonstrated the targeting and anti-tumor efficacy of our therapeutic cytokines in cancer and bone cell models. Ultimately, this will provide the framework for innovative peptide and cytokine-based therapeutics that target and treat both the tumor metastases and bone. This approach will facilitate improvement of morbidity and quality of life of prostate cancer patients with bone metastases and could be applicable to other diseases with bone/tumor pathologies. <br><div><br></div></div>

<p>Embryonic development is a complicated phenomenon influenced by genetic regulation and biomechanical cellular behaviors. However, the relative influence of these factors on spatiotemporal morphogen distributions is not well understood. Bone Morphogenetic Proteins (BMPs) are the primary morphogen guiding the dorsal-ventral (DV) patterning of the early zebrafish embryo, and BMP signaling is regulated by a network of extracellular and intracellular factors that impact the range and signaling of BMP ligands.  Recent advances in understanding the mechanism of pattern formation support a source-sink mechanism, however, it is not clear how the source-sink mechanism shapes patterns in 3D, nor how sensitive the pattern is to biophysical rates and boundary conditions along both the anteroposterior (AP) and DV axes of the embryo.</p><p> Throughout blastulation and gastrulation, major cell movement, known as epiboly, happens along with the BMP mediated DV patterning. The layer of epithelial cells begins to thin as it spreads toward the vegetal pole of the embryo until it has completely engulfed the yolk cell. This dynamic domain may influence the distributions of BMP network members. This project aims to investigate the multiscale regulatory network of the BMP signaling dynamics along with the biophysical deformation of the embryo tissue during epiboly. </p><p> In this study, we present a three-dimensional (3D) growing domain mathematical modeling framework to simulate the BMP patterning and epiboly process during the blastula to gastrula stage zebrafish embryo, with both finite difference and finite element approaching. These models provide a starting point to elucidate how different mechanisms and components work together in 3D to create and maintain the BMP gradient in the zebrafish embryo. We are interested in how the cellular movements impact the formation of gradients by contributing an advective term whereby the morphogens are swept with the moving cells as they move vegetally. Dynamic cell imaging data are used to quantify the cell movement during the epiboly. We evaluated the accuracy of the mesh updating compared to the advection caused by cell movement and its role in embryonic patterning. Quantitative whole-mount RNA scope data of BMP2b, Chordin, Noggin, Sizzled, and phosphorylated-SMAD data are collected and analyzed precisely to test the hypotheses of the gradient formation mechanism in our model. We also present a novel approach of Neuro Network model to accelerate the computationally intensive PDE simulations. Our goal is to develop a complete advection-diffusion-reaction model that incorporates all stages of zebrafish embryonic development data. By combining the biophysics of epiboly with the regulatory dynamics of the BMP network, we can test complex models to investigate the consistent spatiotemporal DV patterning in the early zebrafish embryo.</p>

No description available.

<div><div><div><p>The aorta has many complex features including valve and vessel wall geometry, blood flow, and wall composition. Diseases such as aortic aneurysms and aortic valve lesions affect vessel function and may even lead to rupture, which can be fatal. However, current clinical diagnoses of aortopathies mainly rely on simple parameters such as diameter and growth rate. To better understand aortopathies and ultimately improve patient diagnoses and treatments, it is important to investigate disease progression as well as the effect of vessel wall composition changes and hemodynamic forces on aortic biomechanics, such as strain and wall shear stress distribution. Preclinical research using small animals allows for disease progression to be studied while controlling outside factors. The next important step is to apply the methods used in the preclinical studies to human patient data. Both preclinical and clinical studies often focus on noninvasive, patient-specific methods for further characterizing the biomechanics of the aorta using advanced techniques such as 4D flow magnetic resonance imaging, 4D ultrasound, computational fluid dynamics (CFD), and fluid structure interaction (FSI) modeling. Yet the challenge of bridging these research techniques to a clinical setting remains. Factors such as financial costs, acquisition time, and ease of analysis must be considered. Therefore, the following document highlights two specific aims to extend our knowledge about the effects of aneurysms and aortic valve lesions. We will 1) characterize the regional effects of murine abdominal aortic aneurysms on strain over time, and 2) use CFD and FSI to simulate the hemodynamic effects on the thoracic aorta using both murine and human patient imaging data. Conducting research using clinically translatable methods of biomechanical characterization that consider the complexity of the aorta on a patient-specific basis will contribute to our understanding and lead to better patient outcomes.</p></div></div></div>

<p>  </p> <p>Congenital diseases of the kidney are the leading cause of chronic kidney disease in pediatric patients. Tissue engineering models used to investigate these diseases are limited by an immature phenotype. Models cultured in an extracellular matrix (ECM), a network of proteins and glycosaminoglycans surrounding cells and providing structural support that mimic the matrix found in development will be likely more mature. However, developing kidney ECM composition and structural dynamics are unknown. To address this gap, we studied ECM composition using mass spectrometry and organization by visualizing the ECM in 3D.</p> <p>In this work, we used mass spectrometry to resolve ECM basement membrane and interstitial matrix dynamics between embryonic, perinatal, and adult kidneys. Surprisingly, we observed a transient upregulation of interstitial matrix structures that corresponded to dynamic 3D structures in the cortex (vertical fibers) and at the corticomedullary junction (medullary ray sheath fibers). Notably, in a model of abnormal <em>Foxd1</em>+ stromal cells, the vertical fibers were disorganized, and medullary ray sheath fibers were no longer associated with blood vessels, suggesting the dynamic 3D structures depended on stromal cell modulation.</p> <p>One of the effects of abnormal kidney development is decreased amniotic fluid, which limits embryonic movement and subsequent limb development. In additional studies, we looked at the implications of the lost motility in the muscular dysgenesis (<em>mdg</em>) mouse on the development of the myotendinous junction (MTJ). The MTJ links contractile muscle with tendon. We found the ECM protein COL22A1 was specific to the developing MTJ as early as embryonic day (E)13.5. The development of the MTJ from a linear structure to a cap-like structure with invaginations in adolescent mice depended on muscle contraction. Furthermore, we used a model to decouple the muscle-tendon-bone complex at an ectopic lateral triceps insertion (<em>Prrx1Cretg/+; Tbx3fl/fl</em>). We observed disorganized tendon and MTJ markers at the termination of the ectopic lateral triceps muscle but negligible cartilage markers. Together, this indicated MTJ maturation depended on motility but not on the enthesis.</p> <p>The information gleaned from our studies on how stromal cells affect dynamic 3D interstitial ECM structures and composition change during kidney development can be used as a template for 3D kidney culture systems. Combined with forelimb MTJ development, our results indicate the importance of the interstitial matrix in tissue morphogenesis.</p>

This thesis presents an improved oscillotonometric system for the measurement of human blood pressure. The study included: 1. The design of a hydraulic occlusive cuff, 2. The investigation of the wave forms taken from the blood pressure measurements, and 3. The design of a mechanism for the simulation of human blood pressure pulse. In this study, an experimental system consisting of a rigid shell occlusive cuff, a constant volume displacement pump, a transducer, and a chart recorder was designed and used for data collection.

The currently accepted methods for measuring systemic blood pressure are either highly accurate but invasive in nature or clinically convenient but prone to observer-related errors. A new oscillometric method uses sensitive signal conditioning and sensing equipment with a non-invasive arm cuff to record arterial pulsations. The goal of this study is to establish more reliable criteria for the identification of systolic and diastolic pressures from oscillometric data.

Developing a more scientific way to determine the load threshold for capillary wall failure would be a big step forward in characterizing whether bruising is result from an abuse or an accident. In this thesis, the upper portion of the human arm was modeled and analyzed under dynamic loading conditions. Since the diameter of the arm is much larger than that of the capillary, a four-level hierarchical sub-modeling method was used to mathematically link the transient response of the global arm model to the response of a small volume in the muscle tissue containing one capillary. Soft tissue in the arm was modeled in two distinct ways. In one method each component of soft tissue was modeled used isotropic linear elastic properties to find the loading threshold that produces a hoop stress in the capillary wall equal to the capillary failure stress. In the other approach, nonlinear, hyper-elastic properties for skin, adipose, muscle tissue and capillary wall were employed to make the tissue behavior more realistic to that of a human arm. Material-appropriate constitutive functions were chosen for each layer. A mathematical technique implement in MATLAB was used to estimate and subtract rigid body motion from the total displacement to avoid excessive displacements of sub-models and focus more on the deformation-only displacement. It was found that modeling the skin, adipose, muscle and capillary as hyper-elastic resulted in significantly smaller deformations but larger loads that resulted in capillary failure.

<p>Traumatic brain injury (TBI) is characterized by a violent or sudden blow to the head that causes tearing or bruising of the brain tissue and its supporting blood vessels. Determination of the mechanical properties of gray and white matter is critical for the creation of computational models of healthy and TBI-damaged brain tissues. Current in vivo methods to characterize brain tissue, such as 3D amplified MRI (aMRI) and magnetic resonance elastography (MRE), are highly vulnerable to motion artifacts and have limited techniques to exert mechanical loads on the brain. Therefore, in vitro testing was employed to estimate the chemical composition of gray and white matter using Fourier Transform Infrared (FTIR) spectroscopy and the stress responses of the brain tissues to high compressive deformations via unconfined compression. Attenuated total reflectance (ATR) was run in conjunction with FTIR spectroscopy to eliminate the need for sample preparation. Unconfined compression of gray and white matter samples was performed to 70% of the total sample height at a constant strain rate of 0.35/s. Results showed significant increases in the absorbances of white matter (<em>p</em> < 0.05) in the characteristic lipid and carbohydrate regions of the FTIR spectra when compared to gray matter. Within the initial 10% toe-region of the stress-strain curve, white matter is observed to absorb significantly greater compressive loads (<em>p </em>< 0.05) than gray matter. These results indicate an incomplete characterization of brain tissue; therefore, additional in vitro and in vivo methods are still necessary, separately or in combination, to accurately characterize brain tissue mechanics in TBI and non-TBI patients.</p>

This thesis developed a novel theory of fiber jamming and experimentally verified it. The theory relates the performance, which is the ratio between the stiff and soft states of a fiber jamming chamber, to three relative design parameters: the ratio of the wall thickness to the membrane inner diameter, the ratio of the fiber diameter to membrane inner diameter, and the number of fibers. These three parameters, when held constant across different chamber sizes, hold the performance constant. To test the theory, three different types of fiber jamming chambers were built in three different sizes. Each chamber was set up as a cantilever beam and deflected 10mm in both the un-jammed (soft) and jammed (stiff) states. When the three design parameters were held constant, the performance of the chamber was consistent within 10\%. In contrast, when the parameters were altered, there was a statistically significant $p < .0001$ and noticeable effect on chamber performance. These two results can be used in tandem to design miniaturized fiber jamming chambers. These results also have a direct application in soft robots designed for minimally invasive surgery.