Dongeun Huh, Ph.D. - US grants

DESCRIPTION (provided by applicant): Chronic lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) are leading causes of mortality and morbidity worldwide that impose major economic and societal burdens. In the past decades, considerable progress has been made in identifying and studying disease-specific genes and proteins to understand the molecular mechanisms of underlying disease processes. Yet there is a large disconnect between this biochemical basis of disease and the reality of how these diseases develop and manifest themselves. Scientists and caregivers have long recognized that many chronic lung diseases are associated with abnormal changes in the structure and mechanics of the lung. The current focus of pulmonary research on genetics and biochemistry, however, largely ignores this undeniable physical nature of disease, rendering our fundamental understanding incomplete. The greatest challenge in resolving this lack of knowledge has been in the inability of conventional experimental approaches to recapitulate complex pathological mechanical changes in the lung during disease development and progression. To address this critical barrier, we propose to develop a new paradigm of in vitro studies for pulmonary research by leveraging unique capabilities of microengineering technologies to create new types of surrogate models that reconstitute the structural, functional, and mechanical complexity of chronic lung diseases. Specifically, using asthma as a representative disorder, this proposal aims to develop novel bioengineering approaches based on the synergistic integration of microengineered culture of patient-derived cells with dynamic self-assembly, hydrogel engineering, and multiphase microfluidics to build mechanically active human disease models. We will use a microengineered model of asthma to study whether and how aberrant changes in tissue architecture and local mechanical microenvironment influence airway inflammation and remodeling, which are the defining pathological features of asthma and many other chronic lung diseases. Of particular interest is in examining biomechanical disease processes in the small airways of asthmatic lungs to address the current lack of knowledge regarding inflammatory and remodeling responses in the distal lung during the progression of chronic asthma. This research will address critical technical barriers to progress in pulmonary medicine, mechanobiology and many other related areas, and provide new insights into important biological questions, which may contribute to the identification of new therapeutic targets and intervention strategies.

Abstract Infections are commonly reported onboard spacecraft, but the mechanisms responsible are not well understood. Both tissue-specific and systemic (bone marrow) responses have been implicated. Systems to model and prevent or treat infections in microgravity are important components of mission planning. Our underlying hypothesis is that Immunosuppression in microgravity is due to loss of both local and systemic responses to bacteria that can be modeled and are susceptible to therapy. Based on extensive preliminary data we propose 2 new models to address potential mechanisms of compromised immunity on the ISS. In the UG3 Phase we will develop and refine: 1.An airway-on-a-chip that incorporates a 3-layer topology with both airway and vascular access is used to probe intrinsic susceptibility to airway infections from Pseudomonas aeruginosa in microgravity 2. A bone marrow-on-a-chip that will be used to test mobilization of neutrophils from the marrow in response to physiologic modifiers that induce neutrophil release from marrow. Once validated, these devices will be packaged in remotely- controllable modules that will be sent to the ISS for deployment in microgravity, while control devices subject to unit gravity will be mimicked in a terrestrial facility. Our implementation partners, STaARS ans Space Pharma will be intimately involved in the development and hardening of the tissues on chips in a space-ready fashion, and in establishment of remote control and real-time data recovery from ISS. After successful data gathering and post-flight analysis from the UH3 phase, we will design and implement an integrated device in the UH3 Phase. We propose to interconnect the devices these devices so as to test the interaction between these tissues that controls innate immunity. Similarly, once validated and shown to reflect the physiological principles that control recruitment of innate immune cells to infected organs, the devices will be packaged and deployed to the ISS for a second analysis in microgravity. The goals of the project are to test feasibility of microfluidic devices to reflect physiological principles while being delivered to orbit; and to provide access to modular components that can be interconnected to understand the integrated behavior of complex human responses.

PROJECT SUMMARY Environmental exposures during gestation can alter early growth trajectories and increase the risk of developing chronic diseases including diabetes, hypertension, and obesity. Among the exposures of greatest concern is cadmium, a metal that is extensively used in the electronics industry. Cadmium is a high priority toxicant with adverse clinical effects reported in both adults and children. During pregnancy, cadmium accumulates in the placenta where it induces cellular stress, interferes with hormone production, and limits the transfer of nutrients from mother to child. This leads to smaller offspring size at birth in humans and animal models. Identifying cellular mechanisms that can modify cadmium?s toxicity in the placenta are key to preventing the adverse outcomes associated with fetal growth restriction due to cadmium, a chemical that will persist in our environment for the foreseeable future. One mechanism that reduces placental accumulation of environmental chemicals is active transport by efflux proteins. The breast cancer resistance protein (BCRP/ABCG2), an efflux transporter highly expressed on syncytiotrophoblasts, plays a critical role in restricting the placental accumulation of chemicals. The overarching hypothesis of this research is that BCRP is a critical mechanism limiting placental exposure to cadmium; when BCRP function is reduced, cadmium?s toxic effects on the placenta are enhanced, resulting in fetal growth restriction. This hypothesis will be tested in three specific aims using innovative and translational experimental approaches. The multidisciplinary research team includes a biochemical toxicologist, biomedical engineer, and an epidemiologist. To study the ability of BCRP to prevent cadmium-induced placental toxicity, a complement of culture models, including a novel ?Placenta-on-a-Chip? as well as term villous explants from healthy pregnancies will be used. To test the in vivo ability of BCRP to prevent cadmium-induced fetal growth restriction, transgenic pregnant mice will be treated with cadmium chloride and evaluated for placental toxicity and fetal growth restriction. The UPSIDE cohort of 310 healthy, pregnant women will be examined for prenatal exposure to metals, including cadmium, and transporter genomics/proteomics in relation to 3D placental morphology and infant growth outcomes. Ultimately, this line of research will inform the scientific community regarding the ability of placental transporters to protect the fetus from environmental chemical-induced developmental toxicities.

SUMMARY This proposal leverages our group?s complementary expertise in tissue-on-a-chip technology, immunology, pluripotent cell derivation and differentiation, and islet biology to create robust systems containing human islet cells, immune cells, and other features to recapitulate the process of islet autoimmunity in type I diabetes (T1D). The UG3 phase of this proposal will improve upon already-robust microdevices and develop new cell lines and assays that will enable studies of autoimmunity in an isogenic setting. The UH3 phase of this proposal will exploit these tools and platforms to develop isogenic models that can be used to study immune-islet interactions. The focus of the UH3 phase will be to investigate the determinants of islet infiltration and killing, and to determine the effects of mutations in T1D-associated genes on this process. In addition, these in vitro systems will be used to pilot the use of cellular therapies to interrupt the autoimmune attack of islets. The specific aims of the UG3 phase are: Aim 1: To expand the biomimetic platform Aim 2: To develop models of T cell-mediated autoimmunity Aim 3: To establish new iPSC lines and novel reporters of b cell stress and death The specific aims of the UH3 phase are: Aim 1: To develop isogenic models of autoimmune T1D Aim 2: To identify determinants of islet infiltration and immune killing Aim 3: To perform genetic studies of autoimmunity in T1D