Browsing by Author "Li, Hongyan"

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    LYSMD3: A mammalian pattern recognition receptor for chitin
    He, Xin; Howard, Brad A.; Liu, Yang; Neumann, Aaron K.; Li, Liwu; Menon, Nidhi; Roach, Tiffany; Kale, Shiv D.; Samuels, David C.; Li, Hongyan; Kite, Trenton; Kita, Hirohito; Hu, Tony Y.; Luo, Mengyao; Jones, Caroline N.; Okaa, Uju Joy; Squillace, Diane L.; Klein, Bruce S.; Lawrence, Christopher B. (2021-07-20)
    Chitin, a major component of fungal cell walls, has been associated with allergic disorders such as asthma. However, it is unclear how mammals recognize chitin and the principal receptor(s) on epithelial cells that sense chitin remain to be determined. In this study, we show that LYSMD3 is expressed on the surface of human airway epithelial cells and demonstrate that LYSMD3 is able to bind chitin, as well as beta-glucan, on the cell walls of fungi. Knockdown or knockout of LYSMD3 also sharply blunts the production of inflammatory cytokines by epithelial cells in response to chitin and fungal spores. Competitive inhibition of the LYSMD3 ecto-domain by soluble LYSMD3 protein, multiple ligands, or antibody against LYSMD3 also blocks chitin signaling. Our study reveals LYSMD3 as a mammalian pattern recognition receptor (PRR) for chitin and establishes its role in epithelial cell inflammatory responses to chitin and fungi.
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    Two Essays in Finance: The Consequences of Mandated Compensation Disclosure, and The Idiosyncratic Volatility Puzzle
    Li, Hongyan (Virginia Tech, 2018-06-08)
    This Dissertation consists of two essays. The first essay studies the causal impacts of compensation disclosure on executive compensation, turnover, and executives’ job responsibilities. We find that, after the SEC mandates the disclosure of Chief Financial Officers (CFOs)’ compensation in 2006, CFO pay increases significantly relative to CEO pay, particularly in firms most affected by the mandate. CFOs are more likely to leave their firms following poor performance. The results are absent for the CEO or other executives, suggesting they are unique outcomes of enhanced CFO compensation disclosures. The evidence is consistent with more intense monitoring following the disclosure mandate. CFOs require additional compensation for the loss of private benefits due to greater monitoring and are subject to greater internal discipline. There is also some evidence that the CFOs hide bad news and lower corporate reporting quality after the mandate, suggesting that CFOs engage in more short-term behavior to boost their performance and avoid termination. The second essay of my dissertation focuses on the idiosyncratic volatility puzzle - the negative relation between estimated idiosyncratic volatility and the subsequent month returns documented by Ang et al (2006). We document a systematic pattern of temporary increases in the estimated idiosyncratic volatility for the quintile of stocks with the highest estimated idiosyncratic volatility in a given month. A large portion of this temporary increase in the estimated idiosyncratic volatility is reversed in the subsequent month. This temporary increase in the idiosyncratic volatility for the quintile of stocks with the highest estimated idiosyncratic volatility is associated with relatively large positive returns (positive abnormal returns) in the estimation month and relatively low returns (negative abnormal returns) in the subsequent month. Our evidence shows that these temporary increases in the estimated idiosyncratic volatility and the related positive and negative abnormal returns in the estimation and subsequent months, respectively, create a negative relation between the estimated idiosyncratic volatility and subsequent month returns documented in the prior literature (Ang et al. 2006). We find no significant relation between idiosyncratic volatility and subsequent returns for eighty percent of the stocks that do not exhibit large changes in idiosyncratic volatility despite large differences in the levels of their idiosyncratic volatility. Finally, there is no relation between the estimated idiosyncratic volatility and subsequent returns after a lag of 3 months when the abnormal returns associated with temporary changes are no longer present. Overall, our results are consistent with the notion that there is no relation between the true underlying idiosyncratic volatility and expected returns, and that the previously documented negative relation between estimated idiosyncratic volatility and subsequent month’s returns is being driven by temporary one-month increases in the estimated idiosyncratic volatility and the associated abnormal returns for a subset of stocks.