Jae Lee - US grants

DESCRIPTION (provided by applicant): Diabetes without previous coronary heart disease (CHD) carries a lifetime risk of vascular death as high as that for people with CHD. The goal of this project is to explore and discover novel and more complete regulation mechanisms of atherogenic pathways in diabetes by developing advanced statistical analysis and novel pathway modeling capabilities and techniques based on microarray data collected from animal disease progression models and combined with various functional and genomic database resources. Microarray profiling experiments that follow different diabetic progression conditions of well-established animal models will be cost-effectively executed to obtain genome-wide gene expression information for their atherogenic pathway conditions (measured from visceral fat tissue-derived adipocytes and macrophages). We will carefully examine the atherogenic pathway mechanisms, especially those associated with 12/15-LO and PPARg, which have been targeted by our primary pathway investigation due to their critical physiological roles in atherosclerosis. In particular, the latter has been identified as one of main pharmacological targets for treating cardiovascular complications among type II diabetes patients. Our specific aims are to: 1) discover atherogenic pathway genes, especially relevant to 12/15-LO and PPARg at different stages of diabetic atherosclerosis progression by developing and applying advanced statistical analysis approaches to microarray data on different diabetic animal-model conditions with a small number of replicates, 2) develop a formal language (FL) framework and its genomic information database for various expression and functional information of 12/15-LO, PPARg and other atherogenic genes that will be identified from the time-course microarray data of diabetic animal models and for the genes known for their functions and mechanisms in atherosclerosis, and 3) discover novel atherogenic pathway mechanisms in diabetes, especially those associated with 12/15-LO and PPARg by developing and applying genome integrative pathway modeling (GIPaM) technology. Novel findings from these investigations will directly benefit the diagnosis and treatment of atherosclerotic cardiovascular disease. Our GIPaM technology will also greatly enhance pathway discovery/modeling capability in other fields of the biomedical science.

0854210
Lee

Naturally-occurring methane hydrates have attracted a lot of public attention because they provide enormous potential as a future energy source. Gas storage in the artificial clathrate form is a safe and economical option, safe because the slow release of gas from a container of hydrate reduces explosion hazards, and economical because the gas storage density at 40 bar is comparable to a compressed gas at 200 bar. On the other hand, hydrate plugs formed inside processing lines are a nuisance to gas and oil industries. A critical obstacle to accelerating or retarding hydrate formation is a lack of understanding of the multi-scale interactions between gas hydrate particles and surface-active agents during hydrate formation. To contrast these interactions, methane (CH4) and carbon dioxide (CO2) hydrate systems will be investigated because surface-active agents generally accelerate CH4 hydrate formation but do not affect or even hinder CO2 hydrate formation. Three sequential stages of hydrate formation will be analyzed at different length scales: nucleation (<100 nm), initial growth (> 1 ìm), and layered & agglomerated growth (> 1 mm). Differential scanning calorimetry will be used to quantify the effect of surface-active agents on gas hydrate nucleation by statistical measurements of phase-transitions. The different stages of hydrate growth will be investigated by confocal and transmission electron microscopes to understand how surface-active agents differently affect CH4 and CO2 hydrates in terms of hydrate crystal sizes and porosities.

Intellectual Merit: An important hypothesis to be tested is that the adsorption of surface-active molecules onto the hydrate surface rather than their micellization in bulk phase is the main reason for accelerating and inhibiting gas hydrate formation. The adsorption mechanisms to be studied as part of the proposed research will lead to a fundamental understanding of the role of surface-active agents in achieving different morphologies and formation rates of gas hydrates in terms of the microscopic observations. Novel neutron scattering studies of the microscopic, interfacial structure will clarify the configuration and functionality of surface-active agents at the oil-hydrate-water interface. This knowledge on hydrate morphologies and interfacial phenomena will be connected to the macroscopic, scale-up experiments of bulk-phase reaction.

Broader Impact: The fundamental understanding of the active role of surfactants and hydrate inhibitors enables controlled self-assembly of liquid-phase water molecules into solid gas hydrates. This understanding can be utilized for fast gas hydrate formation needed for safe natural gas storage and CO2 sequestration, while it can also be used for the investigation of an economical alternative to the 1 billion dollars per year spent on methanol as a hydrate inhibitor. This research will be performed by a close collaboration of two institutions, a Ph.D. granting school (CCNY) and an undergraduate liberal-arts college (Hamilton). The PIs will engage underrepresented high school students via existing programs and will actively involve undergraduate students and graduate students via a summer research exchange program between the two institutions. They will investigate gas hydrate-aided CO2 separation from flue gas to incorporate the thermodynamic, kinetic, interfacial science/engineering, and design aspects of this process into the undergraduate and graduate classes at Hamilton and CCNY.

This project is supported by two CBET programs: Interfacial Processes and Thermodynamics; Process and Reaction Engineering

DESCRIPTION (provided by applicant): Acute lung injury (ALI) remains a devastating syndrome affecting more than 200,000 patients annually in the U.S. with a mortality rate approaching 40%. Currently, there are no pharmacologic therapies that reduce mortality. Consequently, further research into translational therapies is needed. Stem cell-based therapy with mesenchymal stem cells (MSC) is one attractive new approach. MSC have the capacity to secrete multiple paracrine factors that can regulate lung endothelial and epithelial permeability, decrease inflammation, enhance tissue repair, and inhibit bacterial growth. In over 150 clinical trials registered with clinicaltrials.gov using MSC as therapy, over 2000 patients have received the cells without any major complications. Despite a favorable safety profile, however, MSC have the capacity for spontaneous malignant transformation following multiple passages in vitro as well as the ability to promote tumor growth in vivo. Recently, some investigators have found that microvesicles (MV) released by human MSC are as biologically active as the stem cells in part through the transfer and expression of MV mRNA in the injured tissue bed. In this application, I propose to study the biology and test the potential therapeutic use of human bone-marrow derived MSC MV as an alternative to cellular therapy in models of ALI. The overall hypothesis is that human MSC MV are biologically active, and that their therapeutic activity is primarily mediated through transfer of mRNA from the MV to injured lung epithelium and lung endothelium. In Aim 1, the primary objective is to study the biology of MSC MV and determine which components of the MSC MV are functionally active, using inhibitors of RNA and protein synthesis and transport. I hypothesize that MSC MV require the transfer of mRNA for key paracrine soluble factors from the MV to the injured lung epithelium or endothelium using a cell membrane receptor, such as CD44, for their therapeutic effect. In Aim 2, I will test the functional activity of human MSC MV on net fluid transport in human alveolar epithelial type II cells and on lung endothelial permeability to protein in human lung microvascular endothelial cells injured by an inflammatory insult, the main pathological features of ALI. I hypothesize that MSC MV will prevent the decrease in net fluid transport in injured type II cells by restoring the apical membrane expression of the major epithelial sodium channel, ¿ENaC, and will reduce the increase in protein permeability in injured lung endothelial cells by preventing the formation of actin stress fibers. In Aim 3, I will determine if human MSC MV are biologically active in mice injured with E.coli endotoxin-induced ALI. I hypothesize that MSC MV will reduce endotoxin-induced ALI in mice by restoring lung endothelial and epithelial protein permeability, lung fluid balance and by reducing alveolar inflammation. These studies will provide novel insights into how MVs are released and the underlying mechanisms that explain why MSC MVs may be effective in tissue repair. Furthermore, the results may provide preclinical data that could facilitate development of MSC MV as a therapy for ALI.

? DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is the fourth-leading cause of cancer-related deaths in the United States with metastasis as the major cause of mortality. The vast majority of PDAC patients will present with metastatic disease with the liver representing the most common site of disease spread. During tumor development, primary tumor cells secrete factors that precondition the liver for metastasis. In this process, th liver becomes a pre-metastatic niche that promotes tumor cell seeding and growth. Macrophages are a prominent component of this niche, yet their role in regulating PDAC metastasis is unknown. Within the tumor microenvironment, the Signal Transducer and Activator of Transcription (STAT) 1 and 3 signaling pathways can play a key role in defining macrophage phenotype with anti- and pro-tumor properties, respectively. Preliminary data demonstrate chronic STAT3 signaling in macrophages residing within the pre-metastatic niche in a genetically engineered murine model of PDAC at a stage prior to the development of invasive disease. In addition, preliminary findings using a murine model of liver metastasis reveal a role for macrophages as key regulators of tumor seeding in PDAC. Thus, the central hypothesis of this proposal is that macrophages residing within the pre-metastatic niche acquire a pro-metastatic phenotype that depends on chronic STAT3 signaling beginning early in tumor development. This hypothesis will be pursued through two specific aims. Aim One will investigate the role of macrophages in regulating metastasis using the LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1-Cre (KPC) murine model of PDAC and a liver metastasis model involving the intrasplenic injection of PDAC cell lines derived from KPC mice. Aim Two will examine the effect of STAT1 and STAT3 signaling on the capacity of macrophages to regulate metastasis using conditional models of STAT3 expression in macrophages. Studies in this proposal will improve the understanding of pathways regulating metastasis in PDAC and may identify novel therapeutic strategies for the treatment of PDAC. This project will be co-sponsored by two experienced investigators with complementary skill sets in immunology and cancer biology and demonstrated commitment to mentorship.

PROJECT SUMMARY/ABSTRACT After spinal cord injury (SCI), the injury site is filled with cellular debris, especially myelin debris that creates a very unique lipid-dense environment. Macrophages are the predominant phagocyte that are responsible for debris-clearance, but this process is not only inefficient, it is also maladaptive. The excessive amount of myelin debris present at the injury site leads to formation lipid-laden macrophages (a.k.a. foamy macrophages) that become pro-inflammatory and contribute to tissue regeneration failure. In addition to macrophages, microglia and fibroblasts also become foam cells. Therefore, understanding the mechanisms of myelin debris uptake and catabolism after SCI may lead to novel therapeutic targets to promote repair after SCI. In this application, we will investigate the mechanism of myelin debris uptake as well as the export of its catabolic byproduct in macrophages, microglia, and fibroblasts after SCI. In addition, we will test the therapeutic potential of novel nanoparticles that can target the uptake and efflux mechanisms.

ABSTRACT Bacterial pneumonia with or without sepsis is among the most common cause of acute respiratory failure in critically ill patients leading to acute respiratory distress syndrome (ARDS). Despite improvements in supportive care and appropriate antibiotic use, mortality from ARDS remains as high as 40%. Therefore, new innovative therapies are needed. Hyaluronan or hyaluronic acid (HA) is normally synthesized as a high molecular weight (HMW) nonsulfated glycosaminoglycan and is a chief component of the extracellular matrix and critical for maintaining the normal structure of alveolar air-blood barrier. In multiple pulmonary disorders including acute lung injury (ALI), asthma, COPD or pulmonary hypertension, HA undergoes degradation by hyaluronidases, reactive oxygen and nitrogen species and inflammatory mediators. The degradation products, low molecular weight (LMW) HA, has inflammatory properties and can decrease endothelial cell barrier function and induce expression of inflammatory mediators. In patients with ARDS, elevated levels of alveolar LMW HA have been associated with increased Lung Injury Score. Surprisingly, HMW HA has biologic properties opposite of LMW HA based primarily due to its molecular size. Therefore, investigators have previously studied the therapeutic use of exogenous administration of HMW HA in lung disorders. Despite promising pre-clinical data, a major limitation for the use of HMW HA for ARDS has remained the concern of giving an immunosuppressive therapy in patients with severe infection. In the current proposal, we hypothesize that administration of HMW HA will further restore major indices of ALI from severe bacterial pneumonia and/or sepsis in part through increased (1) antimicrobial activity and (2) through neutralization of inflammatory extracellular vesicles (EV) released during the exudative phase of ALI. In Aim 1, we will determine the therapeutic effects of HMW HA administration in established mouse models of severe bacterial pneumonia. We hypothesize that the mechanisms underlying the therapeutic effects of HMW HA will be due to increased antimicrobial activity of innate immune cells, binding of inflammatory EVs released early in the exudative phase of ALI, and through the restoration of the endothelial glycocalyx layer. To make the small pre-clinical animal studies more clinically relevant, in Aim 2, we will determine the therapeutic effects of HMW HA administration in an ex vivo perfused human lung injured with severe E.coli or Pseudomonas aeruginosa bacterial pneumonia. And to overcome some of the limitations of the perfused human lung such as a lack of the liver and spleen which are the major sites of HA degradation, in Aim 3, we will determine the therapeutic effects of HMW HA administration in a well-established ovine model of septic shock induced by smoke inhalation and Pseudomonas aeruginosa pneumonia. If successful, HMW HA, an inexpensive, non-immunogenic biologic already in use in clinical trials for other sterile inflammatory pulmonary disorders such as COPD, may prove to be a viable therapy for ARDS and/or sepsis.

  PROJECT SUMMARY/ABSTRACT Lewy body diseases including Parkinson's disease (PD), Lewy body dementia (LBD), and multiple system atrophy are characterized by the accumulation of aggregated alpha-synuclein (?-syn) protein, which is the principal component of Lewy bodies (LBs). Neuroinflammation is the hallmark of Lewy body diseases and the role of the immune system has been implicated in the progression of synuclein pathology and neuropathology. However, the role of cellular immunity in promoting neurodegeneration or exerting neuroprotection remains unclear. We established a preclinical mouse model of ?-synucleinopathy and showed a robust increase in immune responses in the CNS and the periphery. We noted significantly increased peripheral leukocytes including natural killer (NK) cells in the mouse model of ?-synucleinopathy. As innate immune cells, NK cells are of particular interest for neurological disorders because they are modified in the periphery and/or travel into the CNS. It has been shown that NK cell numbers are increased in the blood of PD patients compared to age- matched controls and their activity is associated with disease severity. However, the role of NK cells in the context of PD has never been explored. We recently reported NK cells are present in the substantia nigra of post mortem brains of PD and LBD patients. Based on our experimental data, NK cells efficiently clear ?-syn aggregates and in vivo depletion of NK cells results in exacerbated synuclein pathology, neuroinflammation, and striatal degeneration in a preclinical mouse model of ?-syn aggregation. The proposed study will investigate the mechanism (s) by which NK cells reduces ?-syn burden, modulate inflammation, and exert neuroprotection in the CNS and periphery. We will use both in vitro and in vivo mouse model of synucleinopathies to address the physiological role of NK cells in the context of Lewy body diseases. To test our central hypothesis and achieve our objective we propose three specific aims as follows: In Aim 1, we will investigate the mechanism by which NK cells scavenge ?-syn and modulate ?-syn-induced inflammation and neurotoxicity. In Aim 2, we will determine whether NK cells are neuroprotective in a mouse model of ?-syn aggregations. In Aim 3, we will determine if peripheral NK cell infiltration into the CNS is essential for neuroprotection. To date, there are no therapies available to slow or stop disease progression of synucleinopathies. Our study will provide a comprehensive understanding of the role of NK cells in the context of Lewy body diseases. Therefore, this work can have a positive impact by providing a scientific basis for pursuing NK cells as a potential immunotherapeutic target for aged-related neurodegenerative diseases.