Jin-peng Sun

Name:

Organization: Shandong University

Department: Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology

Title:

Chemicals
References

Construction of an alkaline phosphatase-specific two-photon probe and its imaging application in living cells and tissues

Co-reporter:Huatang Zhang, Peng Xiao, Yin Ting Wong, Wei Shen, Mohit Chhabra, Raoul Peltier, Yin Jiang, Yonghe He, Jun He, Yi Tan, Yusheng Xie, Derek Ho, Yun-Wah Lam, Jinpeng Sun, Hongyan Sun

Biomaterials 2017 Volume 140(Volume 140) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.biomaterials.2017.06.032

Alkaline phosphatase (ALP) is a family of enzymes involved in the regulation of important biological processes such as cell differentiation and bone mineralization. Monitoring the activity of ALP in serum can help diagnose a variety of diseases including bone and liver diseases. There has been growing interest in developing new chemical tools for monitoring ALP activity in living systems. Such tools will help further delineate the roles of ALP in biological and pathological processes. Previously reported fluorescent probes has a number of disadvantages that limit their application, such as poor selectivity and short-wavelength excitation. In this work, we report a new two-photon fluorescent probe (TP-Phos) to selectively detect ALP activity. The probe is composed of a two-photon fluorophore, a phosphate recognition moiety, and a self-cleavable adaptor. It offers a number of advantages over previously reported probes, such as fast reaction kinetics, high sensitivity and low cytotoxicity. Experimental results also showed that TP-Phos displayed improved selectivity over DIFMUP, a commonly utilized ALP probe. The selectivity is attributed to the utilization of an ortho-functionalised phenyl phosphate group, which increases the steric hindrance of the probe and the active site of phosphatases. Moreover, the two-photon nature of the probe confers enhanced imaging properties such as increased penetration depth and lower tissue autofluorescence. TP-Phos was successfully used to image the endogenous ALP activity of hippocampus, kidney and liver tissues from rat.

β-Arrestins promote podocyte injury by inhibition of autophagy in diabetic nephropathy

Co-reporter:J Liu, Q X Li, X J Wang, C Zhang, Y Q Duan, Z Y Wang, Y Zhang, X Yu, N J Li, J P Sun and F Yi

Cell Death & Disease 2016 7(4) pp:e2183

Publication Date(Web):2016-04-01

DOI:10.1038/cddis.2016.89

β-Arrestins are multifunctional proteins originally identified as negative adaptors of G protein-coupled receptors (GPCRs). Emerging evidence has also indicated that β-arrestins can activate signaling pathways independent of GPCR activation. This study was to elucidate the role of β-arrestins in diabetic nephropathy (DN) and hypothesized that β-arrestins contribute to diabetic renal injury by mediating podocyte autophagic process. We first found that both β-arrestin-1 and β-arrestin-2 were upregulated in the kidney from streptozotocin-induced diabetic mice, diabetic db/db mice and kidney biopsies from diabetic patients. We further revealed that either β-arrestin-1 or β-arrestin-2 deficiency (Arrb1−/− or Arrb2−/−) ameliorated renal injury in diabetic mice. In vitro, we observed that podocytes increased both β-arrestin-1 and β-arrestin-2 expression levels under hyperglycemia condition and further demonstrated that β-arrestin-1 and β-arrestin-2 shared common mechanisms to suppress podocyte autophagy by negative regulation of ATG12–ATG5 conjugation. Collectively, this study for the first time demonstrates that β-arrestin-1 and β-arrestin-2 mediate podocyte autophagic activity, indicating that β-arrestins are critical components of signal transduction pathways that link renal injury to reduce autophagy in DN. Modulation of these pathways may be an innovative therapeutic strategy for treating patients with DN.

Identification of a benzo imidazole thiazole derivative as the specific irreversible inhibitor of protein tyrosine phosphatase

Co-reporter:Lin Ge, Kang-shuai Li, Meng-meng Li, Peng Xiao, Xu-ben Hou, Xu Chen, Hong-da Liu, Amy Lin, Xiao Yu, Gui-jie Ren, Hao Fang, Jin-peng Sun

Bioorganic & Medicinal Chemistry Letters 2016 Volume 26(Issue 19) pp:4795-4798

Publication Date(Web):1 October 2016

DOI:10.1016/j.bmcl.2016.08.024

Protein tyrosine phosphatases (PTPs) play key roles in many physiological processes, including cell proliferation, differentiation, immune responses and neural activities. Inappropriate regulation of the PTP activity could lead to human diseases, such as cancer or diabetes. Functional studies of PTP can be greatly facilitated by chemical probes that covalently label the active site of a PTP through an activity-dependent chemical reaction. Here, we characterize compound E4 as a new class of PTP activity probes. Compound E4 inactivate STEP in a time- and concentration-dependent fashion. Further study showed that compound E4 inhibits a series of PTPs in a time dependent manner, whereas it shows little or no inhibition toward metal dependent protein phosphatases. Collectively, this new identified covalent inhibitor of PTPs has the potential to be developed to an active site Cys directed PTP probes to study the active properties of the PTPs in cell signaling.

Different downstream signalling of CCK1 receptors regulates distinct functions of CCK in pancreatic beta cells

Co-reporter:Shang-lei Ning;Wen-shuai Zheng;Jing Su;Nan Liang;Hui Li;Dao-lai Zhang;Chun-hua Liu;Jun-hong Dong;Zheng-kui Zhang;Min Cui;Qiao-Xia Hu;Chao-chao Chen;Chang-hong Liu;Chuan Wang;Qi Pang;Yu-xin Chen;Xiao Yu

British Journal of Pharmacology 2015 Volume 172( Issue 21) pp:5050-5067

Publication Date(Web):

DOI:10.1111/bph.13271

Background and Purpose

Cholecystokinin (CCK) is secreted by intestinal I cells and regulates important metabolic functions. In pancreatic islets, CCK controls beta cell functions primarily through CCK₁ receptors, but the signalling pathways downstream of these receptors in pancreatic beta cells are not well defined.

Experimental Approach

Apoptosis in pancreatic beta cell apoptosis was evaluated using Hoechst-33342 staining, TUNEL assays and Annexin-V-FITC/PI staining. Insulin secretion and second messenger production were monitored using ELISAs. Protein and phospho-protein levels were determined by Western blotting. A glucose tolerance test was carried out to examine the functions of CCK-8s in streptozotocin-induced diabetic mice.

Key Results

The sulfated carboxy-terminal octapeptide CCK_26-33 amide (CCK-8s) activated CCK₁ receptors and induced accumulation of both IP₃ and cAMP. Whereas G_q-PLC-IP₃ signalling was required for the CCK-8s-induced insulin secretion under low-glucose conditions, G_s-PKA/Epac signalling contributed more strongly to the CCK-8s-mediated insulin secretion in high-glucose conditions. CCK-8s also promoted formation of the CCK₁ receptor/β-arrestin-1 complex in pancreatic beta cells. Using β-arrestin-1 knockout mice, we demonstrated that β-arrestin-1 is a key mediator of both CCK-8s-mediated insulin secretion and of its the protective effect against apoptosis in pancreatic beta cells. The anti-apoptotic effects of β-arrestin-1 occurred through cytoplasmic late-phase ERK activation, which activates the 90-kDa ribosomal S6 kinase-phospho–Bcl-2-family protein pathway.

Conclusions and Implications

Knowledge of different CCK₁ receptor-activated downstream signalling pathways in the regulation of distinct functions of pancreatic beta cells could be used to identify biased CCK₁ receptor ligands for the development of new anti-diabetic drugs.

Identification of para-Substituted Benzoic Acid Derivatives as Potent Inhibitors of the Protein Phosphatase Slingshot

Co-reporter:Dr. Kang-shuai Li;Dr. Peng Xiao;Dr. Dao-lai Zhang;Dr. Xu-Ben Hou;Dr. Lin Ge;Dr. Du-xiao Yang;Dr. Hong-da Liu;Dr. Dong-fang He;Dr. Xu Chen;Dr. Ke-rui Han; Xiao-yuan Song; Xiao Yu; Hao Fang

ChemMedChem 2015 Volume 10( Issue 12) pp:1980-1987

Publication Date(Web):

DOI:10.1002/cmdc.201500454

Abstract

Slingshot proteins form a small group of dual-specific phosphatases that modulate cytoskeleton dynamics through dephosphorylation of cofilin and Lim kinases (LIMK). Small chemical compounds with Slingshot-inhibiting activities have therapeutic potential against cancers or infectious diseases. However, only a few Slingshot inhibitors have been investigated and reported, and their cellular activities have not been examined. In this study, we identified two rhodanine-scaffold-based para-substituted benzoic acid derivatives as competitive Slingshot inhibitors. The top compound, (Z)-4-((4-((4-oxo-2-thioxo-3-(o-tolyl)thiazolidin-5-ylidene)methyl)phenoxy)methyl)benzoic acid (D3) had an inhibition constant (K_i) of around 4 μm and displayed selectivity over a panel of other phosphatases. Moreover, compound D3 inhibited cell migration and cofilin dephosphorylation after nerve growth factor (NGF) or angiotensin II stimulation. Therefore, our newly identified Slingshot inhibitors provide a starting point for developing Slingshot-targeted therapies.

The catalytic region and PEST domain of PTPN18 distinctly regulate the HER2 phosphorylation and ubiquitination barcodes

Co-reporter:Hong-Mei Wang, Yun-Fei Xu, Shang-Lei Ning, Du-Xiao Yang, Yi Li, Yu-Jie Du, Fan Yang, Ya Zhang, Nan Liang, Wei Yao, Ling-Li Zhang, Li-Chuan Gu, Cheng-Jiang Gao, Qi Pang, Yu-Xin Chen, Kun-Hong Xiao, Rong Ma, Xiao Yu and Jin-Peng Sun

Cell Research 2014 24(9) pp:1067-1090

Publication Date(Web):August 1, 2014

DOI:10.1038/cr.2014.99

The tyrosine phosphorylation barcode encoded in C-terminus of HER2 and its ubiquitination regulate diverse HER2 functions. PTPN18 was reported as a HER2 phosphatase; however, the exact mechanism by which it defines HER2 signaling is not fully understood. Here, we demonstrate that PTPN18 regulates HER2-mediated cellular functions through defining both its phosphorylation and ubiquitination barcodes. Enzymologic characterization and three crystal structures of PTPN18 in complex with HER2 phospho-peptides revealed the molecular basis for the recognition between PTPN18 and specific HER2 phosphorylation sites, which assumes two distinct conformations. Unique structural properties of PTPN18 contribute to the regulation of sub-cellular phosphorylation networks downstream of HER2, which are required for inhibition of HER2-mediated cell growth and migration. Whereas the catalytic domain of PTPN18 blocks lysosomal routing and delays the degradation of HER2 by dephosphorylation of HER2 on pY1112, the PEST domain of PTPN18 promotes K48-linked HER2 ubiquitination and its rapid destruction via the proteasome pathway and an HER2 negative feedback loop. In agreement with the negative regulatory role of PTPN18 in HER2 signaling, the HER2/PTPN18 ratio was correlated with breast cancer stage. Taken together, our study presents a structural basis for selective HER2 dephosphorylation, a previously uncharacterized mechanism for HER2 degradation and a novel function for the PTPN18 PEST domain. The new regulatory role of the PEST domain in the ubiquitination pathway will broaden our understanding of the functions of other important PEST domain-containing phosphatases, such as LYP and PTPN12.

Fast Identification of Novel Lymphoid Tyrosine Phosphatase Inhibitors Using Target–Ligand Interaction-Based Virtual Screening

Co-reporter:Xuben Hou ; Rong Li ; Kangshuai Li ; Xiao Yu ; Jin-Peng Sun ;Hao Fang

Journal of Medicinal Chemistry 2014 Volume 57(Issue 22) pp:9309-9322

Publication Date(Web):November 5, 2014

DOI:10.1021/jm500692u

Lymphoid-specific tyrosine phosphatase (Lyp), a critical signaling regulator of immune cells, is associated with various autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and systemic lupus erythematosus. Recent research suggests that Lyp is a potential drug target for autoimmune diseases. Herein, we applied a target–ligand interaction-based virtual screening method to identify novel Lyp inhibitors. Nine Lyp inhibitors with novel scaffolds were identified with eight reversible inhibitors (Ki values ranged from 2.87 to 28.03 μM) and one covalent inhibitor (Ki = 40.98 ± 13.19 μM). The top four compounds (A2, A15, A19, and A26) displayed selectivity over other phosphatases in preliminary experiments, and kinetic analysis indicated that these compounds are competitive inhibitors of Lyp. Compounds A15 and A19 up-regulated TCR (T cell receptor) mediated signaling and transcriptional activation through inhibition of Lyp activity in T cells. The new chemotypes of Lyp selective inhibitors identified through the target–ligand interaction-based virtual screening may provide new leads for Lyp targeted therapeutic development.

Understanding cadherin EGF LAG seven-pass G-type receptors

Co-reporter:Xiao-Jing Wang;Dao-Lai Zhang;Zhi-Gang Xu;Ming-Liang Ma;Wen-Bo Wang;Lin-Lin Li;Xiao-Lin Han;Yuqing Huo;Xiao Yu

Journal of Neurochemistry 2014 Volume 131( Issue 6) pp:699-711

Publication Date(Web):

DOI:10.1111/jnc.12955

Molecular mechanism of ERK dephosphorylation by striatal-enriched protein tyrosine phosphatase

Co-reporter:Rong Li;Di-Dong Xie;Jun-hong Dong;Hui Li;Kang-shuai Li;Jing Su;Lai-Zhong Chen;Yun-Fei Xu;Hong-Mei Wang;Zheng Gong;Guo-Ying Cui;Xiao Yu;Kai Wang;Wei Yao;Tao Xin;Min-Yong Li;Kun-Hong Xiao;Xiao-fei An;Yuqing Huo;Zhi-gang Xu;Qi Pang

Journal of Neurochemistry 2014 Volume 128( Issue 2) pp:315-329

Publication Date(Web):

DOI:10.1111/jnc.12463

Adaptive Activation of a Stress Response Pathway Improves Learning and Memory Through Gs and β-Arrestin-1–Regulated Lactate Metabolism

Co-reporter:Jun-Hong Dong, Yi-Jing Wang, Min Cui, Xiao-Jing Wang, Wen-Shuai Zheng, Ming-Liang Ma, Fan Yang, Dong-Fang He, Qiao-Xia Hu, Dao-Lai Zhang, Shang-Lei Ning, Chun-Hua Liu, Chuan Wang, Yue Wang, Xiang-Yao Li, Fan Yi, Amy Lin, Alem W. Kahsai, Thomas Joseph Cahill III, Zhe-Yu Chen, Xiao Yu, et al.

Biological Psychiatry (15 April 2017) Volume 81(Issue 8) pp:654-670

Publication Date(Web):15 April 2017

DOI:10.1016/j.biopsych.2016.09.025