Recent Research
Yan Zhang, MD, PhD
Yan Zhang, MD, PhD
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Research Interests
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Long-Term Imposed Hyperopic Defocus Induced Gene Expression Changes in Chick RPE: A Microarray Study
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To identify the growth factors and related genes that are critical to myopia development, with the purpose of targeting them for therapeutic intervention, a semi-quantitative genome-wide gene expression profiling study using DNA microarray screening was performed, and we found that of the ~ 30,000 chick genes screened, more than 800 were up- or down-regulated equal or greater than 1.5 folds. Follow-up studies investigating these candidate genes turned to be very successful and productive. A group of growth factors and cytokines, mostly from the TGF-β family, in chick RPE that are differentially regulated with visual manipulations and altered eye growth were identified and followed with further studies.
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Role of RPE-Derived BMP and TGF-β in Eye Growth Regulation and Myopia Development
One of the most significant findings of my research is the bidirectional, optical sign-dependent regulation of BMP gene expression in chick RPE with short-term (2 & 48 hours) optical induced defocus treatments that either accelerate or slow eye growth in young chicks. The 2 h short-term treatment allows us to identify genes important for eye growth initiation, before detectable changes in eye growth occur, while genes showing differential expression after 48 h of treatment are assumed to be critical for maintaining the altered growth pattern, as by this time altered growth is detectable. Relevant findings from my recent studies are that three members of BMP family, BMP2, BMP4, and BMP7, all show bidirectional changes in expression in the RPE of lens-treated eyes, the direction depending on the sign of imposed optical defocus, with some differences in temporal expression patterns also evident. To follow up the bidirectional, optical sign-dependent regulation of BMP2, 4, 7 gene expression, a series of studies were conducted to elucidate the role of BMP in eye growth regulation. These findings open up a new avenue for investigation into the regulation of eye growth and the involvement of the RPE during emmetropization.
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Investigate the Mechanisms of Eye Growth Regulation Using In Vitro Cell Culture Models
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Using the chick as an animal model for myopia in combination with human/chick RPE cell cultures and chick scleral fibroblast cultures, molecular and cellular signaling pathways involving these growth factors during ocular growth regulation are currently being investigated. The findings from these studies have the potential to open new avenues for myopia treatment.
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