Zhaolu Lu

The human cationic antimicrobial protein LL-37 is a multifunctional host defense peptide with a wide range of immunomodulatory activities. Previous work has shown that LL-37 exerts both pro- and anti-inflammatory effects. The role of mitochondria in the skin inflammatory effects of LL-37 has not been well studied. Therefore, our aim was to investigate the immunomodulatory effect of LL-37 in HaCaT cells and to delineate the underlying mechanisms related to mitochondrial function. Immunohistochemistry results from tissue microarrays showed strong cytoplasmic LL-37 staining in inflammatory cells in chronic dermatic inflammation. Using exogenous LL-37 stimulation and LL-37 knockdown and overexpression, LL-37 was demonstrated to dramatically reduce the mRNA levels and protein secretion of inflammatory cytokines including IL-6, IL-8, IL-1α and tumor necrosis factor-α, which are induced by lipopolysaccharides. The anti-inflammatory effects of LL-37 are dependent upon its ability to increase mitochondrial biogenesis and to maintain mitochondrial homeostasis. Furthermore, we observed that LL-37 enhances the LPS-induced phosphorylation of extracellular signal-regulated kinase and mammalian target of rapamycin. The mTOR inhibitor rapamycin can neutralize the protective effects of LL-37 on mitochondria. In conclusion, these results suggest that high LL-37 expression levels correlate with chronic skin inflammation; mitochondrial dysfunction occurs in HaCaT cells during inflammation; and LL-37 attenuates inflammatory impairment by stimulating mitochondrial biogenesis and protecting mitochondrial function, which are dependent upon mTOR signaling. These findings provide new insights into targeting mitochondria with LL-37 to prevent skin inflammatory reactions. © 2014 Elsevier Ltd.

Contactin-Associated protein-like 2 is a large multidomain neuronal adhesion molecule implicated in a number of neurological disorders, including epilepsy, schizophrenia, autism spectrum disorder, intellectual disability, and language delay. We reveal here by electron microscopy that the architecture of CNTNAP2 is composed of a large, medium, and small lobe that flex with respect to each other. Using epitope labeling and fragments, we assign the F58C, L1, and L2 domains to the large lobe, the FBG and L3 domains to the middle lobe, and the L4 domain to the small lobe of the CNTNAP2 molecular envelope. Our data reveal that CNTNAP2 has a very different architecture compared with neurexin 1α, a fellow member of the neurexin superfamily and a prototype, suggesting that CNTNAP2 uses a different strategy to integrate into the synaptic protein network. We show that the ectodomains of CNTNAP2 and contactin 2 bind directly and specifically, with low nanomolar affinity. We show further that mutations in CNTNAP2 implicated in autism spectrum disorder arenot segregated but are distributed over the whole ectodomain. The molecular shape and dimensions of CNTNAP2 place constraints on how CNTNAP2 integrates in the cleft of axo-glial and neuronal contact sites and how it functions as an organizing and adhesive molecule.

DNA base pairing has been used for many years to direct the arrangement of inorganic nanocrystals into small groupings and arrays with tailored optical and electrical properties. The control of DNA-mediated assembly depends crucially on a better understanding of three-dimensional structure of DNA-nanocrystal-hybridized building blocks. Existing techniques do not allow for structural determination of these flexible and heterogeneous samples. Here we report cryo-electron microscopy and negative-staining electron tomography approaches to image, and three-dimensionally reconstruct a single DNA-nanogold conjugate, an 84-bp double-stranded DNA with two 5-nm nanogold particles for potential substrates in plasmon-coupling experiments. By individual-particle electron tomography reconstruction, we obtain 14 density maps at ~ 2-nm resolution. Using these maps as constraints, we derive 14 conformations of dsDNA by molecular dynamics simulations. The conformational variation is consistent with that from liquid solution, suggesting that individual-particle electron tomography could be an expected approach to study DNA-assembling and flexible protein structure and dynamics.

The thesis title, "A Direct-Realist Alternative to Inferentialist Theories of Perceptual Knowledge," aptly describes what I have attempted to achieve in this dissertation: I have sought to develop and defend a strong direct-realist alternative to the traditional inferentialist model, the model called the Establishment by its two most prominent contemporary defenders, Jerry Fodor and Zenon Pylyshyn. ;My research project has been motivated by the conviction that the development of a correct epistemology lies in the acceptance of the possibility of a direct, noninferential, epistemically unmediated comprehension of things and events. In the thesis I argue against Fodor and Pylyshyn's Establishment theory, and develop a Dretskean information-theoretic account, a Gibsonian ecological approach, and a Searlean intentional account, all of which combine to provide a radical alterative to orthodox inferentialism. ;A major part of the thesis is devoted to explicating the concepts of perceptual illusion and "proper object" of perception. The upshot of this effort is a position that provides strong support for a theory of direct empirical knowledge of objects, events, and facts. The thesis contains four chapters as follows. ;Chapter one deals with the debate between the Establishment and the Gibsonians. It focuses on the psychological basis of direct realism. The Establishment's "argument from illusion" is disarmed. ;Chapter two discusses a Dretskean version of direct reaIism. Dretske's theories on the nonepistemic character of perception, the proper objects of perception, the character of perceptual representation and misrepresentation are carefully reviewed and compared with Gibson's ecological psychology. I also defend Dretske's position against some of his critics. ;Chapter three discusses a Searlean version of direct realism. Searle's internalist position on the intentionality of perception is carefully examined and contrasted with Dretske's information-theoretic account of perception. The discussion in this chapter focuses on the intentional content and character of perception, particularly the causally self-referential character of perception. ;Chapter four is devoted to a development of a model gleaned, most of all, from the contributions made by Dretske, but also from those of Gibson and Searle, insofar as their contributions jibe with Dretske's position. I think this final position is a very strong one, and I attempt in the final chapter to indicate some of the directions profitable research might take

This paper evaluates Tu Wei-ming's proposal that the Confucian ideal model of human society should be viewed as a fiduciary community. To do the evaluation, I provide a systematic elaboration of Tu's proposal, which is essentially absent in Tu's writings, and a systematic explication of the Confucian theory of fiduciarity, which is supposed to be the theoretical foundation of Tu's proposal but is completely absent in the studies of Confucianism, including Tu's own. On the basis of these studies, I conclude that the notion of fiduciary community is entailed by the Confucian tradition; tapping the resource of the Confucian tradition for appreciating, supporting and justifying a properly defined model of fiduciary society is practically relevant and important to the modern world; however, given Tu's own definition, the model of fiduciary community does not sufficiently characterise the Confucian ideal society. In the end, I suggest a new way to study Confucian social ideals.