An Explorer of Chemical Biology of Plant Natural Products in Southwest China,Xiaojiang Hao

Xiaojiang Hao,who obtained Master Degree from Kunming Institute of Botany(KIB),Chinese Academy of Sciences(CAS)in 1985,and Doctor in Pharmacy degree in Pharmacy from Institute for Chemical Research,Kyoto University,in 1990,was born in Chongqing in July,1951.In 1991,he returned to KIB,CAS,as an Associate professor and served as the chair of the Department of Phytochemistry.In 1994,he was promoted to a full professor at the current institute.He served as the Deputy Director of KIB and the Director of Open Laboratory of Phytochemistry from 1995 to 1997,and the Director of KIB from 1997 to 2005.Professor Hao has published more than 450 peer-reviewed SCI papers,which have been cited over 6000 times.He has obtained one PCT patent and 23 patents in China.Due to his tremendous efforts,one candidate drug,phenchlobenpyrrone,has entered the Phase II clinical trail for the treatment of Alzheimer’s disease.Moreover,he won the First Prize of Natural Sciences in Yunnan Province for three times,and Ho Leung Ho Lee Fund Science and Technology Innovation Award in 2017.

Integrated Systems Biology and Chemical Biology Approach to Exploring Mechanisms of Traditional Chinese Medicines

After thousands of years of development, traditional Chinese medicines （TCMs） have evolved into a complete scientific system characterized by multiple components, targets, and pathways, which mediates numerous pharmacological activities and efficacies. The development of ＂-omics＂ technology, including systems biology and network pharmacology, has enabled the illustration of TCMs from a more systematic view. Although the network adequately reflects the overall philosophy of TCMs, its complexity hinders the relevant research to a hover. In addition, the strategies involved appear to be in contrast to the original concise and efficacious disease therapy oriented focus on classic Chinese material medica （CMM）. Based on the established holistic view and reductionism, in this review, we discuss an integrated systems biology and chemical biology research approach that will facilitate and accelerate the understanding of the mechanisms of TCMs. Furthermore, we are optimistic that it will elucidate the associated interactions between active natural products and their targets, and ultimately improve the strategies for complex disease therapies.

Isolation and characterization ofβ-transducin repeat-containing protein ligands screened using a high-throughput screening system

β-transducin repeat-containing protein(β-TrCP)is an F-box protein subunit of the E3 Skp1-Cullin-F box(SCF)type ubiquitin-ligase complex,and provides the substrate specificity for the ligase.To find potent ligands ofβ-TrCP useful for the proteolysis targeting chimera(PROTAC)system usingβ-TrCP in the future,we developed a high-throughput screening system for small moleculeβ-TrCP ligands.We screened the chemical library utilizing the system and obtained several hit compounds.The effects of the hit compounds on in vitro ubiquitination activity of SCFβ-TrCP1 and on downstream signaling pathways were examined.Hit compounds NPD5943,NPL62020-01,and NPL42040-01 inhibited the TNFα-induced degradation of IκBαand its phosphorylated form.Hence,they inhibited the activation of the transcription activity of NF-κB,indicating the effective inhibition ofβ-TrCP by the hit compounds in cells.Next,we performed an in silico analysis of the hit compounds to determine the important moieties of the hit compounds.Carboxyl groups of NPL62020-01 and NPL42040-01 and hydroxyl groups of NPD5943 created hydrogen bonds withβ-TrCP similar to those created by intrinsic target phosphopeptides ofβ-TrCP.Our findings enhance our knowledge of useful small molecule ligands ofβ-TrCP and the importance of residues that can be ligands ofβ-TrCP.

An atypical ubiquitin ligase at the heart of neural development and programmed axon degeneration

The degeneration of nerve fibres following injury was first described by Augustus Waller over 170 years ago.Initially assumed to be a passive process,it is now evident that axons respond to insult via regulated cellular signaling events resulting in their programmed degeneration.Pro-survival and prodegenerative factors have been identified and their regulato ry mechanisms are beginning to emerge.The ubiquitin system has been implicated in the pro-degenerative process and a key component is the ubiquitin E3 ligase MYCBP2(also known as PHR1).Ubiquitin E3 ligases are tasked with the transfer of the small protein modifier ubiquitin to substrates and consist of hundreds of members.They can be classified as single subunit systems or as multi-subunit complexes.Their catalytic domains can also be assigned to three general architectures.Hints that MYCBP2 might not conform to these established formats came to light and it is now clear from biochemical and structural studies that MYCBP2 is indeed an outlier in terms of its modus operandi.Furthermore,the unconventional way in which MYCBP2 transfe rs ubiquitin to substrates has been linked to neurodevelopmental and pro-degenerative function.Herein,we will summarize these research developments relating to the unusual features of MYCBP2 and postulate therapeutic strategies that prevent Walle rian degeneration.These have exciting potential for providing relief from pathological neuropathies and neurodegenerative diseases.

An Approach to Quantify Endomembrane Dynamics in Pollen Utilizing Bioactive Chemicals

Tip growth of pollen tubes and root hairs occurs via rapid polar growth. These rapidly elongating cells require tip-focused endomembrane trafficking for the deposition and recycling of proteins, membranes, and cell wall materials. Most of the image-based data published to date are subjective and non-quantified. Quantitative and com- parative descriptors of these highly dynamic processes have been a major challenge, but are highly desirable for genetic and chemical genomics approaches to dissect this biological network. To address this problem, we screened for small molecules that perturbed the localization of a marker for the Golgi Ras-like monomeric G-protein RAB2：GFP expressed in transgenic tobacco pollen. Semi-automated high-throughput imaging and image analysis resulted in the identifica- tion of novel compounds that altered pollen tube development and endomembrane trafficking. Six compounds that caused mislocalization and varying degrees of altered movement of RAB2：GFP-labeled endomembrane bodies were used to generate a training set of image data from which to quantify vesicle dynamics. The area, velocity, straightness, and intensity of each body were quantified using semi-automated image analysis tools revealing quantitative differences in the phenotype caused by each compound. A score was then given to each compound enabling quantitative comparisons between compounds. Our results demonstrate that image analysis can be used to quantitatively evaluate dynamic sub- cellular endomembrane phenotypes induced by bioactive chemicals, mutations, or other perturbing agents as part of a strategy to quantitatively dissect the endomembrane network.

Development and Application of a Chemical Labeling-Based Biosensing Assay for Rapid Detection of 8-Oxoguanine and Its Repair in vitro and in Human Cells

Living cells are constantly threatened by endogenous and environmental agents that can induce various DNA lesions including 8-oxoguanine(8-oxoG).Increasing evidence has suggested that 8-oxoG is not only a biomarker of oxidative stress,but also a novel epigenetic-like modification involved in transcriptional regulation in mammalian cells.Measurement of DNA damage and repair is useful for both basic research and clinical applications,but current methods for 8-oxoG detection still suffer from some problems such as poor selectivity,time consuming and being expensive.Here,we developed a fast and simple biosensing approach for quantitative analysis of 8-oxoG in DNA,which was based on the selective chemical biotinylation of 8-oxoG in conjunction with biotin-streptavidin enzyme-linked immunosorbent assay.We have also successfully applied this method to achieve efficient detection of the repair activities of DNA glycosylases Fpg and hOGG1 toward 8-oxoG in vitro and in human cells.This newly developed biosensing assay should be generally applicable for rapid detection of 8-oxoG and its repair in other organisms.

荧光分子探针助力疾病标志物检测

荧光分子探针已成为当代化学生物学和生物医药领域不可或缺的研究工具,被成功应用于活细胞内重要生物物种的动态可视化和人类重大疾病的早期诊治研究.本文总结了包括阴、阳离子,活性氧、氮、碳、硫物种和酶在内的重要生物标志物在疾病发生发展中的生物学功能,以及细胞和活体层次靶向可视化这些标志物的荧光分子探针前沿进展,归纳了现有探针体系所面临的问题和挑战,并展望了该领域的发展方向.

Function-Oriented Natural Product Synthesis

Natural products and their derivatives have long been used as medicinal agents,and they still make up a significant fraction of clinically approved drugs.Natural product synthesis provides a rich and unparalleled opportunity to develop new synthetic transformations,conceive novel and general strategies to access complex structures,and study the mechanism of action of bioactive targets.The combination of the tools and principles of chemistry,together with the tools of modern biology,allows us to create complex synthetic and natural molecules,comprising processes with novel biological,chemical and physical properties.This account will illustrate the opportunities that lie at this interface between synthetic organic chemistry and chemical biology by describing a series of examples that we are actively working on in our laboratory at Peking University.We take the inspiration from mother nature to develop new synthetic strategies to achieve the efficient synthesis of complex natural products.In addition,we also conduct chemical biology studies for these bioactive natural products to elucidate their cellular targets and mode of action.Moreover,we further use bioactive natural products to explore new biology and develop novel drug candidates for human diseases,such as cancers and infectious diseases.