Yin Chen
Assistant Professor, BIO5 Institute
Associate Professor, Pharmacology and Toxicology
Primary Department
(520) 626-4715
Research Interest
Yin Chen, PhD. is an Assistant Professor in Pharmacology and Toxicology in the College of Pharmacy at UA. Dr. Chen’s research focus is on epithelial biology. He was a research faculty in University of California, Davis and an Assistant Investigator in Chemical Industry Institute of Toxicology (former CIIT and later Hamner Institute). His long-term research objective is to understand the dysfunction of airway epithelial mucosa in the pathogenesis of a variety of acute and chronic airway diseases. His current research programs are: a) understanding the molecular mechanisms underlying airway mucous cell development and mucous cell metaplasia in chronic diseases including cancer, COPD and asthma; (b) understanding the function and regulation of novel COPD associated genes and developing novel compounds to treat COPD; (c) understanding the impact of fungal exposure on airway innate immunity and its contribution to the development and exacerbation of asthma. Dr. Chen has more than 30 publications including peer-reviewed research articles, reviews and book chapters. He has served as the PI on one R01, two R21, one Flight Attendant Medical Institute (FAMRI) Innovative Clinical Award and one Arizona Biomedical Research Commission Award. He has also served as co-PI on two R01 and one P01 grants. He has built a long productive track record in studying airway mucus production and respiratory viral infection using primary airway epithelial cell model. He routinely cultivate and use primary epithelial cells from eye, salivary gland, airway surface and submucosal gland in different species (e.g. human, monkey, pig, rat and mouse) as our in vitro model to study mucin genes. The differentiated primary culture model demonstrates pseudostratified morphology, is composed of ciliated, non-ciliated, and goblet cells, and has a transepithelial barrier with high electro-resistance. He has also established in vivo exposure system to study the pulmonary effect of the exposure to particulates, pathogens and gases. Using this system, he has developed various airway disease models including CS-induced COPD model, ovalbumin-induced asthma model, fungal-induced asthma model and several infection models such as H1N1, rhinovirus, Aspergillus, and Alternaria.

Publications

Hao, Y., Kuang, Z., Walling, B. E., Bhatia, S., Sivaguru, M., Chen, Y., Gaskins, H. R., & Lau, G. W. (2012). Pseudomonas aeruginosa pyocyanin causes airway goblet cell hyperplasia and metaplasia and mucus hypersecretion by inactivating the transcriptional factor FoxA2. Cellular Microbiology, 14(3), 401-415.

PMID: 22103442;Abstract:

The redox-active exotoxin pyocyanin (PCN) can be recovered in 100μM concentrations in the sputa of bronchiectasis patients chronically infected with Pseudomonas aeruginosa (PA). However, the importance of PCN within bronchiectatic airways colonized by PA remains unrecognized. Recently, we have shown that PCN is required for chronic PA lung infection in mice, and that chronic instillation of PCN induces goblet cell hyperplasia (GCH), pulmonary fibrosis, emphysema and influx of immune cells in mouse airways. Many of these pathological features are strikingly similar to the mouse airways devoid of functional FoxA2, a transcriptional repressor of GCH and mucus biosynthesis. In this study, we postulate that PCN causes and exacerbates GCH and mucus hypersecretion in bronchiectatic airways chronically infected by PA by inactivating FoxA2. We demonstrate that PCN represses the expression of FoxA2 in mouse airways and in bronchial epithelial cells cultured at an air-liquid interface or conventionally, resulting in GCH, increased MUC5B mucin gene expression and mucus hypersecretion. Immunohistochemical and inhibitor studies indicate that PCN upregulates the expression of Stat6 and EGFR, both of which in turn repress the expression of FoxA2. These studies demonstrate that PCN induces GCH and mucus hypersecretion by inactivating FoxA2. © 2011 Blackwell Publishing Ltd.

Zhu, L., Jingbo, P. i., Wachi, S., Andersen, M. E., Reen, W. u., & Chen, Y. (2008). Identification of Nrf2-dependent airway epithelial adaptive response to proinflammatory oxidant-hypochlorous acid challenge by transcription profiling. American Journal of Physiology - Lung Cellular and Molecular Physiology, 294(3), L469-L477.

PMID: 18156441;Abstract:

In inflammatory diseases of the airway, a high level (estimated to be as high as 8 mM) of HOCl can be generated through a reaction catalyzed by the leukocyte granule enzyme myeloperoxidase (MPO). HOCl, a potent oxidative agent, causes extensive tissue injury through its reaction with various cellular substances, including thiols, nucleotides, and amines. In addition to its physiological source, HOCl can also be generated by chlorine gas inhalation from an accident or a potential terrorist attack. Despite the important role of HOCl-induced airway epithelial injury, the underlying molecular mechanism is largely unknown. In the present study, we found that HOCl induced dose-dependent toxicity in airway epithelial cells. By transcription profiling using GeneChip, we identified a battery of HOCl-inducible antioxidant genes, all of which have been reported previously to be regulated by nuclear factor erythroid-related factor 2 (Nrf2), a transcription factor that is critical to the lung antioxidant response. Consistent with this finding, Nrf2 was found to be activated time and dose dependently by HOCl. Although the epidermal growth factor receptor-MAPK pathway was also highly activated by HOCl, it was not involved in Nrf2 activation and Nrf2-dependent gene expression. Instead, HOCl-induced cellular oxidative stress appeared to lead directly to Nrf2 activation. To further understand the functional significance of Nrf2 activation, small interference RNA was used to knock down Nrf2 level by targeting Nrf2 or enhance nuclear accumulation of Nrf2 by targeting its endogenous inhibitor Keap1. By both methods, we conclude that Nrf2 directly protects airway epithelial cells from HOCl-induced toxicity. Copyright © 2008 the American Physiological Society.

Floyd, A. M., Zhou, X., Evans, C., Rompala, O. J., Zhu, L., Wang, M., & Chen, Y. (2012). Mucin Deficiency Causes Functional and Structural Changes of the Ocular Surface. PLoS ONE, 7(12).

PMID: 23272068;PMCID: PMC3525643;Abstract:

MUC5AC is the most abundant gel-forming mucin in the ocular system. However, the specific function is unknown. In the present study, a Muc5ac knockout (KO) mouse model was subject to various physiological measurements as compared to its wide-type (WT) control. Interestingly, when KO mice were compared to WT mice, the mean tear break up time (TBUT) values were significantly lower and corneal fluorescein staining scores were significantly higher. But the tear volume was not changed. Despite the lack of Muc5ac expression in the conjunctiva of KO mice, Muc5b expression was significantly increased in these mice. Corneal opacification, varying in location and severity, was found in a few KO mice but not in WT mice. The present results suggest a significant difference in the quality, but not the quantity, of tear fluid in the KO mice compared to WT mice. Dry eye disease is multifactorial and therefore further evaluation of the varying components of the tear film, lacrimal unit and corneal structure of these KO mice may help elucidate the role of mucins in dry eye disease. Because Muc5ac knockout mice have clinical features of dry eye, this mouse model will be extremely useful for further studies regarding the pathophysiology of the ocular surface in dry eye in humans. © 2012 Floyd et al.

Zhu, L., Barret, E. C., Yuxue, X. u., Liu, Z., Manoharan, A., & Chen, Y. (2013). Regulation of Cigarette Smoke (CS)-Induced Autophagy by Nrf2. PLoS ONE, 8(4).

PMID: 23585825;PMCID: PMC3621864;Abstract:

Cigarette smoke (CS) has been reported to induce autophagy in airway epithelial cells. The subsequent autophagic cell death has been proposed to play an important pathogenic role in chronic obstructive pulmonary disease (COPD); however, the underlying molecular mechanism is not entirely clear. Using CS extract (CSE) as a surrogate for CS, we found that it markedly increased the expressions of both LC3B-I and LC3B-II as well as autophagosomes in airway epithelial cells. This is in contrast to the common autophagy inducer (i.e., starvation) that increases LC3B-II but reduces LC3B-I. Further studies indicate that CSE regulated LC3B at transcriptional and post-translational levels. In addition, CSE, but not starvation, activated Nrf2-mediated adaptive response. Increase of cellular Nrf2 by either Nrf2 overexpression or the knockdown of Keap1 (an Nrf2 inhibitor) significantly repressed CSE-induced LC3B-I and II as well as autophagosomes. Supplement of NAC (a GSH precursor) or GSH recapitulated the effect of Nrf2, suggesting the increase of cellular GSH level is responsible for Nrf2 effect on LC3B and autophagosome. Interestingly, neither Nrf2 activation nor GSH supplement could restore the repressed activities of mTOR or its downstream effctor-S6K. Thus, the Nrf2-dependent autophagy-suppression was not due to the re-activation of mTOR-the master repressor of autophagy. To search for the downstream effector of Nrf2 on LC3B and autophagosome, we tested Nrf2-dependent genes (i.e., NQO1 and P62) that are also increased by CSE treatment. We found that P62, but not NQO1, could mimic the effect of Nrf2 activation by repressing LC3B expression. Thus, Nrf2->P62 appears to play an important role in the regulation of CSE-induced LC3B and autophagosome. © 2013 Zhu et al.

Yoneda, K., Chang, M. M., Chmiel, K., Chen, Y., & Reen, W. u. (2003). Application of high-density DNA microarray to study smoke- and hydrogen peroxide-induced injury and repair in human bronchial epithelial cells. Journal of the American Society of Nephrology, 14(SUPPL. 3), S284-S289.

PMID: 12874447;Abstract:

Recent advances in high-density DNA microarray technique allow the possibility to analyze thousands of genes simultaneously for their differential gene expression patterns in various biologic processes. Through clustering analysis and pattern recognition, the significance of these differentially expressed genes can be recognized and correlated with the biologic events that may take place inside the cell and tissue. High-density DNA microarray nylon membranes were used to explore gene expression and regulation associated with smoke-and hydrogen peroxide-induced injury and repair in differentiated human bronchial epithelial cells in vitro. At least three phases of change in gene expression could be recognized. The first phase seems to be an immediate event in response to oxidant injury. This phase includes the induction of bcl-2 and mdm2 genes that are involved in the regulation of apoptosis, and the mitogen-activated protein kinase phosphatase 1 that functions as a regulator for various mitogen-activated protein kinase activities. The second phase, usually 5 h later, includes the induction of various stress proteins and ubiquitin, which are important in providing the chaperone mechanism and the turnover of damaged macromolecules. The third phase, which is 5 to 10 h later, includes the induction of genes that seem to be involved in reducing oxidative stress by metabolizing the cellular level of reactive oxygen species. In this phase, enzymes associated with tissue and cell remodeling are also elevated. These results demonstrated a complex gene expression array by bronchial epithelial cells in response to a single insult of oxidants that are relevant to environmental pollutants.