Publications by authors named "Wenjia Lai"

20 Publications

  • Page 1 of 1

CD151 enrichment in exosomes of luminal androgen receptor breast cancer cell line contributes to cell invasion.

Biochimie 2021 Jun 23;189:65-75. Epub 2021 Jun 23.

Laboratory of Theoretical and Computational Nanoscience, CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China; Sino-Danish Center for Education and Research, University of Chinese Academy of Sciences, Beijing, 100190, PR China. Electronic address:

Breast cancer is the most common and highly heterogeneous disease in women worldwide. Given the challenges in the treatment of advanced metastatic breast cancer, it is necessary to understand the molecular mechanisms related to disease progression. Exosomes play various roles in the progression of tumors, including promoting the invasion and advancing the distant metastasis. To study the molecular mechanisms related to the progression of luminal androgen receptor (LAR) breast cancer, we first isolated exosomes of MDA-MB-453 cells, a representative cell line of LAR. Through quantitative proteomic analysis, we identified 180 proteins specifically enriched in exosomes after comparing with those in cells, microvesicles, and the 150K supernatant. Among these, CD151, a protein involved in the regulation of cell motility was the most enriched one. CD151-knockdown exosomes reduced the invasion ability of the recipient breast cancer cell and lowered the phosphorylation level of tyrosine-protein kinase Lck, indicating that the invasion of LAR breast cancer may be due to CD151-enriched exosomes. Our work reports for the first time that CD151 was highly abundant in the exosomes of MDA-MB-453 cells and expands the understanding of the development process of LAR subtype, suggesting CD151 may be a potential candidate for the treatment of LAR breast cancer.
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http://dx.doi.org/10.1016/j.biochi.2021.06.007DOI Listing
June 2021

Biocompatibility of Bacterial Magnetosomes as MRI Contrast Agent: A Long-Term In Vivo Follow-Up Study.

Nanomaterials (Basel) 2021 May 7;11(5). Epub 2021 May 7.

Laboratory of Theoretical and Computational Nanoscience, CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China.

Derived from magnetotactic bacteria (MTB), magnetosomes consist of magnetite crystals enclosed within a lipid bilayer membrane and are known to possess advantages over artificially synthesized nanoparticles because of the narrow size distribution, uniform morphology, high purity and crystallinity, single magnetic domain, good biocompatibility, and easy surface modification. These unique properties have increasingly attracted researchers to apply bacterial magnetosomes (BMs) in the fields of biology and medicine as MRI imaging contrast agents. Due to the concern of biosafety, a long-term follow-up of the distribution and clearance of BMs after entering the body is necessary. In this study, we tracked changes of BMs in major organs of mice up to 135 days after intravenous injection using a combination of several techniques. We not only confirmed the liver as the well-known targeted organs of BMs, but also found that BMs accumulated in the spleen. Besides, two major elimination paths, as well as the approximate length of time for BMs to be cleared from the mice, were revealed. Together, the results not only confirm that BMs have high biocompatibility, but also provide a long-term in-vivo assessment which may further help to forward the clinical applications of BMs as an MRI contrast agent.
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http://dx.doi.org/10.3390/nano11051235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151038PMC
May 2021

Comprehensive role of thermal combined ultrasonic pre-treatment in sewage sludge disposal.

Sci Total Environ 2021 Oct 19;789:147862. Epub 2021 May 19.

Aix-Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, 13100 Aix en Provence, France.

Thermal/ultrasonic pre-treatment of sludge has been proven to break the hydrolysis barriers of sewage sludge (SS) and improve the performance of anaerobic digestion (AD). In this study, the objective was to investigate whether the combination of two pre-treatment methods can achieve better results on the AD of SS. The results indicated that, compared with the control group and separate pre-treatment groups, the thermal combined ultrasonic pre-treatment presented more obvious solubilization of soluble proteins, polysaccharides, and other organic matters in SS. The combined method promoted the dissolution of protein-like substances more effectively, with biogas production increased by 19% and the volatile solid (VS) removal rate improved to above 50% compared with the control group. The capillary suction time is reduced by about 85%, which greatly improved the dewatering performance of SS. In addition, the combined method has advantages in degrading sulfonamide antibiotics, roxithromycin and tetracycline. Particularly, by analyzing the interaction between the degradation of different antibiotics and the composition of dissolved organic matters (DOMs), it was found that the composition of DOMs could affect the degradability of different antibiotics. Among them, the high content of tyrosine-like and tryptophan-like was conducive to the degradation of sulfamethoxazole, and the high content of fulvic acid-like and humic acid-like was conducive to the degradation of roxithromycin and tetracycline. This work evaluated the comprehensive effect of thermal combined ultrasonic pre-treatment on SS disposal and provided useful information for its engineering.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147862DOI Listing
October 2021

Mass spectrometry-based screening identifies circulating immunoglobulinA-α1-microglobulin complex as potential biomarker in immunoglobulin A nephropathy.

Nephrol Dial Transplant 2021 04;36(5):782-792

Department of Medicine, Renal Division, Peking University First Hospital, Beijing, China, and Peking University Institute of Nephrology, Beijing, China.

Background: Immunoglobulin A nephropathy (IgAN) is characterized by predominant IgA deposition in the glomerular mesangium. Previous studies have proved that renal-deposited IgA in IgAN came from circulating IgA1-containing complexes (CICs).

Methods: To explore the composition of CICs in IgAN, we isolated CICs from IgAN patients and healthy controls and then quantitatively analyzed them by mass spectrometry. Meanwhile, the isolated CICs were used to treat human mesangial cells to monitor mesangial cell injury. Using the protein content and injury effects, the key constituent in CICs was identified. Then the circulating levels of identified key constituent-IgA complex were detected in an independent population by an in-house-developed enzyme-linked immunosorbent assay.

Results: By comparing the proteins of CICs between IgAN patients and controls, we found that 14 proteins showed significantly different levels. Among them, α1-microglobulin content in CICs was associated with not only in vitro mesangial cell proliferation and monocyte chemoattractant protein 1 secretion, but also in vivo estimated glomerular filtration rate (eGFR) levels and tubulointerstitial lesions in IgAN patients. Moreover, we found α1-microglobulin was prone to bind aberrant glycosylated IgA1. Additionally, elevated circulating IgA-α1-microglobulin complex levels were detected in an independent IgAN population and IgA-α1-microglobulin complex levels were correlated with hypertension, eGFR levels and Oxford T- scores in these IgAN patients.

Conclusions: Our results suggest that the IgA-α1-microglobulin complex is an important constituent in CICs and that circulating IgA-α1-microglobulin complex detection might serve as a potential noninvasive biomarker detection method for IgAN.
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http://dx.doi.org/10.1093/ndt/gfaa352DOI Listing
April 2021

A Protein Corona Adsorbed to a Bacterial Magnetosome Affects Its Cellular Uptake.

Int J Nanomedicine 2020 6;15:1481-1498. Epub 2020 Mar 6.

CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.

Purpose: It is well known that when exposed to human blood plasma, nanoparticles are predominantly coated by a layer of proteins, forming a corona that will mediate the subsequent cell interactions. Magnetosomes are protein-rich membrane nanoparticles which are synthesized by magnetic bacteria; these have gained a lot of attention owing to their unique magnetic and biochemical characteristics. Nevertheless, whether bacterial magnetosomes have a corona after interacting with the plasma, and how such a corona affects nanoparticle-cell interactions is yet to be elucidated. The aim of this study was to characterize corona formation around a bacterial magnetosome and to assess the functional consequences.

Methods: Magnetosomes were isolated from the magnetotactic bacteria, (MSR-1). Size, morphology, and zeta potential were measured by transmission electron microscopy and dynamic light scattering. A quantitative characterization of plasma corona proteins was performed using LC-MS/MS. Protein absorption was further examined by circular dichroism and the effect of the corona on cellular uptake was investigated by microscopy and spectroscopy.

Results: Various serum proteins were found to be selectively adsorbed on the surface of the bacterial magnetosomes following plasma exposure, forming a corona. Compared to the pristine magnetosomes, the acquired corona promoted efficient cellular uptake by human vascular endothelial cells. Using a protein-interaction prediction method, we identified cell surface receptors that could potentially associate with abundant corona components. Of these, one abundant corona protein, ApoE, may be responsible for internalization of the magnetosome-corona complex through LDL receptor-mediated internalization.

Conclusion: Our findings provide clues as to the physiological response to magnetosomes and also reveal the corona composition of this membrane-coated nanomaterial after exposure to blood plasma.
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http://dx.doi.org/10.2147/IJN.S220082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065717PMC
May 2020

ER complex proteins are required for rhodopsin biosynthesis and photoreceptor survival in Drosophila and mice.

Cell Death Differ 2020 02 1;27(2):646-661. Epub 2019 Jul 1.

National Institute of Biological Sciences, Beijing, 102206, China.

Defective rhodopsin homeostasis is one of the major causes of retinal degeneration, including the disease Retinitis pigmentosa. To identify cellular factors required for the biosynthesis of rhodopsin, we performed a genome-wide genetic screen in Drosophila for mutants with reduced levels of rhodopsin. We isolated loss-of-function alleles in endoplasmic reticulum membrane protein complex 3 (emc3), emc5, and emc6, each of which exhibited defective phototransduction and photoreceptor cell degeneration. EMC3, EMC5, and EMC6 were essential for rhodopsin synthesis independent of the ER associated degradation (ERAD) pathway, which eliminates misfolded proteins. We generated null mutations for all EMC subunits, and further demonstrated that different EMC subunits play roles in different cellular functions. Conditional knockout of the Emc3 gene in mice led to mislocalization of rhodopsin protein and death of cone and rod photoreceptor cells. These data indicate conserved roles for EMC subunits in maintaining rhodopsin homeostasis and photoreceptor function, and suggest that retinal degeneration may also be caused by defects in early biosynthesis of rhodopsin.
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http://dx.doi.org/10.1038/s41418-019-0378-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206144PMC
February 2020

Comparison of the Use of Blink Rate and Blink Rate Variability for Mental State Recognition.

IEEE Trans Neural Syst Rehabil Eng 2019 05 20;27(5):867-875. Epub 2019 Mar 20.

Recent research has unearthed that blink rate variability (BRV) can be employed as a psychophysiological measure. However, its efficiency for mental state recognition (MSR) has not been investigated yet. Because BRV can indicate dynamics inherent in eye blinks, we conjectured that BRV might exhibit stronger abilities for the MSR if compared with blink rate (BR), known as the leading indicator derived from eye blinks for MSR. Therefore, in this paper, we attempted to differentiate between high and low cognitive loads of an individual through the analyses of BR and BRV, respectively, which could be viewed as a preliminary study for comparing their MSR abilities. First, an n -back experiment was performed to collect data. Then, in order to characterize the phenomenon of BRV, the features were extracted from its time and frequency domains, respectively. Finally, the area under the curve (AUC) values of BRV and BR for MSR were estimated by the ten commonly used classifiers, respectively. The results indicated that BRV achieves significantly higher AUC values than BR, which suggests its strong potentiality for MSR. In sum, the BRV may prove to be a promising method for the MSR, which should be considered in the future.
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http://dx.doi.org/10.1109/TNSRE.2019.2906371DOI Listing
May 2019

Plastin 3 down-regulation augments the sensitivity of MDA-MB-231 cells to paclitaxel via the p38 MAPK signalling pathway.

Artif Cells Nanomed Biotechnol 2019 Dec;47(1):685-695

a CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety , CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China , Beijing , China.

Plastin 3 (PLS3) overexpression may serve as a marker for predicting chemotherapeutic outcomes in drug-resistant cancer cells, but the mechanism is unclear. Herein, we show that the down-regulation of PLS3 by PLS3 gene silencing augments the sensitivity of MDA-MB-231 triple-negative breast cancer cells to paclitaxel. Interestingly, a low concentration of paclitaxel was able to induce strong apoptosis in the PLS3-silenced cells. Further study revealed that p38 MAPK signalling was responsible for the increased sensitivity to paclitaxel in these cells, as the p38 MAPK inhibitor SB203580 impaired the changes mediated by PLS3 down-regulation in response to paclitaxel. Therefore, our study identifies PLS3 as a potential target for enhancing the p38 MAPK-mediated apoptosis induced by paclitaxel. Unlike paclitaxel, Abraxane was unable to induce strong apoptosis in the PLS3-silenced cells. As PLS3 was found to be involved in the process of endocytosis in breast cancer cells, the reliance of cellular Abraxane uptake on this process may render it not as efficient as paclitaxel in PLS3-depleted tumour cells. The finding that PLS3 could be a critical regulator of paclitaxel sensitivity may have important implications for breast cancer chemotherapy.
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http://dx.doi.org/10.1080/21691401.2019.1576707DOI Listing
December 2019

Proteomic profiling of RAW264.7 macrophage cells exposed to graphene oxide: insights into acute cellular responses.

Nanotoxicology 2019 02 17;13(1):35-49. Epub 2019 Jan 17.

a CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety , CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology , Beijing , China.

Although the toxicity and molecular mechanisms of graphene oxide (GO) have been reported for several cell types, no proteomic study of GO has yet been conducted on macrophage cells. In this study, we used proteomics based on stable isotope labeling with amino acids in cell culture (SILAC) to quantify the proteomic changes in macrophage RAW 264.7 cells following GO treatment. We found 73 proteins that were significantly dysregulated after GO treatment. The down-regulated proteins included many ribosomal subunit proteins, indicating that GO affected cell growth. The most elevated proteins were lipoprotein lipase (LPL) and lysozyme 1 (LYZ1) which have not been reported before, and both can be used as candidate markers for GO exposure. Further enrichment analysis of the up-regulated proteins indicated these proteins are associated with the integrin complex and membrane rafts, as well as with two signal pathways: the phagosome and steroid biosynthesis pathways. We confirmed a GO concentration-dependent increase in membrane rafts and the production of phagosomes. GO exposure also induced necrotic cell death and an inflammation response in RAW 264.7 cells. We also observed an increase in the oxidative stress response (ROS) and autophagy, and the results suggest that ROS induced autophagy by the ROS-NRF2-P62 pathway.
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http://dx.doi.org/10.1080/17435390.2018.1530389DOI Listing
February 2019

Quantitative proteomic analysis to the first commercialized liposomal paclitaxel nano-platform Lipusu revealed the molecular mechanism of the enhanced anti-tumor effect.

Artif Cells Nanomed Biotechnol 2018 19;46(sup3):S147-S155. Epub 2018 Sep 19.

a CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety , CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China , Beijing , China.

The first nano-platform commercialized as a drug delivery system was a liposomal formulation. The application of liposome technology resolved the issues of paclitaxel (PTX) insolubility and eliminated the use of solvents causing toxic side-effects, which enabled to apply higher drug doses leading to an enhanced drug efficacy. The growth-inhibitory activity of liposome-encapsulated PTX was retained in vitro against a variety of tumor cell. To investigate the drug efficacy in the system biological level, quantitative proteomic analysis was employed to study the molecular mechanism of the anti-tumor effect of Lipusu (lip) compared with PTX on lung cancer cell A549. The functions of the differential expressed proteins were correlated to the negative effect to cell proliferation due to regulation of hippo pathway and prolonged cell cycle, as well as inhibitory cell exocytosis, which would cause the aggregation of free PTX. This investigation focused on the direct biological effect of lip to cancer cells. It was different from pharmaceutical issues about drug exposure, delivery and distribution which were widely investigated in other traditional studies. It was the first study about the drug effect of lip from the global molecular biological aspect.
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http://dx.doi.org/10.1080/21691401.2018.1489822DOI Listing
June 2019

Interaction of gold and silver nanoparticles with human plasma: Analysis of protein corona reveals specific binding patterns.

Colloids Surf B Biointerfaces 2017 Apr 20;152:317-325. Epub 2017 Jan 20.

Key Laboratory for Biological Effects of Nanomaterials and Nanosafety of Chinese Academy of Sciences, Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China; University of Chinese Academy of Sciences, Beijing, 100049, P.R. China. Electronic address:

Determining how nanomaterials interact with plasma will assist in understanding their effects on the biological system. This work presents a systematic study of the protein corona formed from human plasma on 20nm silver and gold nanoparticles with three different surface modifications, including positive and negative surface charges. The results show that all nanoparticles, even those with positive surface modifications, acquire negative charges after interacting with plasma. Approximately 300 proteins are identified on the coronas, while 99 are commonly found on each nanomaterial. The 20 most abundant proteins account for over 80% of the total proteins abundance. Remarkably, the surface charge and core of the nanoparticles, as well as the isoelectric point of the plasma proteins, are found to play significant roles in determining the nanoparticle coronas. Albumin and globulins are present at levels of less than 2% on these nanoparticle coronas. Fibrinogen, which presents in the plasma but not in the serum, preferably binds to negatively charged gold nanoparticles. These observations demonstrate the specific plasma protein binding pattern of silver and gold nanoparticles, as well as the importance of the surface charge and core in determining the protein corona compositions. The potential downstream biological impacts of the corona proteins were also investigated.
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http://dx.doi.org/10.1016/j.colsurfb.2017.01.037DOI Listing
April 2017

Tumor detection using magnetosome nanoparticles functionalized with a newly screened EGFR/HER2 targeting peptide.

Biomaterials 2017 01 16;115:53-64. Epub 2016 Nov 16.

CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, China; CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China. Electronic address:

A novel peptide (P75) targeting EGFR and HER2 is successfully screened from a one-bead-one-compound (OBOC) library containing approximately 2 × 10 peptides built with the aid of computational simulation. In vitro and in vivo analyses show that P75 binds to human epithelial growth factor receptor (EGFR) with nanomolar affinity and to epithelial growth factor receptor-2 (HER2) with a lower affinity but comparable to other reported peptides. The peptide is used to modify the surface of magnetosome nanoparticles (NPs) for targeted magnetic resonance imaging (MRI). In vitro and in vivo fluorescence imaging results suggest peptide P75 modified magnetosomes (Mag-P75) specifically bind to MDA-MB-468 and SKBR3 cells as well as xenograft tumors with surprisingly low accumulation in other organs including liver and kidney. In vivo T-weighted MR imaging studies of the xenograft tumors from SKBR3 and MDA-MB-468 cells show obviously negative contrast enhancement. The high affinity and specificity of P75 to EGFR and HER2 positive tumors, together with the success of peptide functionalized magnetosome NPs for targeted MRI demonstrate the potential of this peptide being used in the EGFR and HER2 positive tumors diagnosis and therapy.
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http://dx.doi.org/10.1016/j.biomaterials.2016.11.022DOI Listing
January 2017

An Evaluation of Blood Compatibility of Silver Nanoparticles.

Sci Rep 2016 05 5;6:25518. Epub 2016 May 5.

Key Laboratory of Standardization and Measurement for Nanotechnology of Chinese Academy of Sciences, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.

Silver nanoparticles (AgNPs) have tremendous potentials in medical devices due to their excellent antimicrobial properties. Blood compatibility should be investigated for AgNPs due to the potential blood contact. However, so far, most studies are not systematic and have not provided insights into the mechanisms for blood compatibility of AgNPs. In this study, we have investigated the blood biological effects, including hemolysis, lymphocyte proliferation, platelet aggregation, coagulation and complement activation, of 20 nm AgNPs with two different surface coatings (polyvinyl pyrrolidone and citrate). Our results have revealed AgNPs could elicit hemolysis and severely impact the proliferation and viability of lymphocytes at all investigated concentrations (10, 20, 40 μg/mL). Nevertheless, AgNPs didn't show any effect on platelet aggregation, coagulation process, or complement activation at up to ~40 μg/mL. Proteomic analysis on AgNPs plasma proteins corona has revealed that acidic and small molecular weight blood plasma proteins were preferentially adsorbed onto AgNPs, and these include some important proteins relevant to hemostasis, coagulation, platelet, complement activation and immune responses. The predicted biological effects of AgNPs by proteomic analysis are mostly consistent with our experimental data since there were few C3 components on AgNPs and more negative than positive factors involving platelet aggregation and thrombosis.
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http://dx.doi.org/10.1038/srep25518DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4857076PMC
May 2016

Peroxiredoxin 6 Is a Crucial Factor in the Initial Step of Mitochondrial Clearance and Is Upstream of the PINK1-Parkin Pathway.

Antioxid Redox Signal 2016 Mar 19;24(9):486-501. Epub 2016 Feb 19.

1 State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University , Beijing, China .

Aims: PTEN-putative kinase 1 (PINK1)-Parkin-mediated mitophagy is crucial for the clearance of damaged mitochondria. However, the mechanisms underlying PINK1-Parkin-mediated mitophagy are not fully understood. The goal of this study is to identify new regulators and to elucidate the regulatory mechanisms of mitophagy.

Results: Quantitative mitochondrial proteomic analysis revealed that 63 proteins showed increased levels and 36 proteins showed decreased levels in cells subjected to carbonyl cyanide m-chlorophenyl hydrazone (CCCP) treatment. Peroxiredoxin 6 (PRDX6 or Prx6), a unique member of the ubiquitous PRDX family, was recruited to depolarized mitochondria. Reactive oxygen species (ROS) generated by CCCP promoted PRDX6 accumulation and PINK1 stabilization in damaged mitochondria and induced mitophagy. In addition, depletion of PRDX6 resulted in the stabilization of PINK1, accumulation of autophagic marker, p62, translocation of Parkin to mitochondria, and lipidation of microtubule-associated protein 1 light chain 3. Furthermore, these events were blocked upon supplementation with antioxidant N-acetyl-l-cysteine or depletion of PINK1.

Innovation: This is the first study to demonstrate that PRDX6 is the only member of the PRDX family that relocates to damaged mitochondria, where it plays a crucial role in the initial stage of mitophagy by controlling ROS homeostasis.

Conclusion: ROS induce the recruitment of PRDX6 to mitochondria, where PRDX6 controls ROS homeostasis in the initial step of PINK1-Parkin-mediated mitophagy. Our study provides new insight into the initial regulatory mechanisms of mitophagy and reveals the protective role of PRDX6 in the clearance of damaged mitochondria.
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http://dx.doi.org/10.1089/ars.2015.6336DOI Listing
March 2016

Structure-based Design of Peptides with High Affinity and Specificity to HER2 Positive Tumors.

Theranostics 2015 1;5(10):1154-65. Epub 2015 Aug 1.

CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, China.

To identify peptides with high affinity and specificity against human epidermal growth factor receptor 2 (HER2), a series of peptides were designed based on the structure of HER2 and its Z(HER2:342) affibody. By using a combination protocol of molecular dynamics modeling, MM/GBSA binding free energy calculations, and binding free energy decomposition analysis, two novel peptides with 27 residues, pep27 and pep27-24M, were successfully obtained. Immunocytochemistry and flow cytometry analysis verified that both peptides can specifically bind to the extracellular domain of HER2 protein at cellular level. The Surface Plasmon Resonance imaging (SPRi) analysis showed that dissociation constants (K D) of these two peptides were around 300 nmol/L. Furthermore, fluorescence imaging of peptides against nude mice xenografted with SKBR3 cells indicated that both peptides have strong affinity and high specificity to HER2 positive tumors.
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http://dx.doi.org/10.7150/thno.12398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4533098PMC
April 2016

Quantitative proteomics reveals that PEA15 regulates astroglial Aβ phagocytosis in an Alzheimer's disease mouse model.

J Proteomics 2014 Oct 7;110:45-58. Epub 2014 Aug 7.

State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China. Electronic address:

Unlabelled: Amyloid-beta (Aβ) deposition plays a crucial role in the progression of Alzheimer's disease (AD). The Aβ deposited extracellularly can be phagocytosed and degraded by surrounding activated astrocytes, but the precise mechanisms underlying Aβ clearance mediated by astrocytes remain unclear. In this study, we performed tandem mass tag-based quantitative proteomic analysis on the cerebral cortices of 5-month-old APP/PS1 double-transgenic mice. Among the 2668 proteins quantified, 35 proteins were upregulated and 12 were downregulated, with most of these proteins being shown here for the first time to be differently expressed in the APP/PS1 mouse. The altered proteins were involved in molecular transport, lipid metabolism, autophagy, inflammation, and oxidative stress. One specific protein, PEA15 (phosphoprotein enriched in astrocytes 15 kDa) upregulated in APP/PS1 mice, was verified to play a critical role in astrocyte-mediated Aβ phagocytosis. Furthermore, PEA15 levels were determined to increase with age in APP/PS1 mice, indicating that Aβ stimulated the upregulation of PEA15 in the APP/PS1 mouse. These results highlight the function of PEA15 in astrocyte-mediated Aβ phagocytosis, and thus provide novel insight into the molecular mechanism underlying Aβ clearance. The protein-expression profile revealed here should offer new clues to understand the pathogenesis of AD and potential therapeutic targets for AD.

Biological Significance: Activated astrocytes are known to clear the Aβ deposited in the extracellular milieu, which is why they play a key role in regulating the progression of Alzheimer's disease (AD). However, the molecular mechanism underlying astrocyte-mediated Aβ phagocytosis and degradation remains unclear. By performing tandem mass tag-based quantitative proteomic analysis, we identified 47 proteins that were differentially expressed in APP/PS1 double-transgenic. To our knowledge, this is the first time most of these proteins have been reported to exhibit altered expression in the mouse model of AD. Furthermore, our results indicate that one of the proteins upregulated in the APP/PS1 mouse, PEA15 (phosphoprotein enriched in astrocytes 15 kDa), regulates astroglial phagocytosis of Aβ. Our findings provide new insights into the molecular mechanism underlying Aβ clearance in AD. The altered profile of protein expression in APP/PS1 mice described here should offer valuable clues to understand the pathogenesis of AD and facilitate the identification of potential targets for the treatment of AD.
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http://dx.doi.org/10.1016/j.jprot.2014.07.028DOI Listing
October 2014

Bimodal imprint chips for peptide screening: integration of high-throughput sequencing by MS and affinity analyses by surface plasmon resonance imaging.

Anal Chem 2014 Apr 24;86(8):3703-7. Epub 2014 Mar 24.

CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, National Center for Nanoscience and Technology of China , Beijing 100190, China.

Peptide probes and drugs have widespread applications in disease diagnostics and therapy. The demand for peptides ligands with high affinity and high specificity toward various targets has surged in the biomedical field in recent years. The traditional peptide screening procedure involves selection, sequencing, and characterization steps, and each step is manual and tedious. Herein, we developed a bimodal imprint microarray system to embrace the whole peptide screening process. Silver-sputtered silicon chip fabricated with microwell array can trap and pattern the candidate peptide beads in a one-well-one-bead manner. Peptides on beads were photocleaved in situ. A portion of the peptide in each well was transferred to a gold-coated chip to print the peptide array for high-throughput affinity analyses by surface plasmon resonance imaging (SPRi), and the peptide left in the silver-sputtered chip was ready for in situ single bead sequencing by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Using the bimodal imprint chip system, affinity peptides toward AHA were efficiently screened out from the 7 × 10(4) peptide library. The method provides a solution for high efficiency peptide screening.
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http://dx.doi.org/10.1021/ac500465eDOI Listing
April 2014

In vitro bioactivity and biocompatibility evaluation of bulk nanostructured titanium in osteoblast-like cells by quantitative proteomic analysis.

J Mater Chem B 2013 Apr 28;1(14):1926-1938. Epub 2013 Feb 28.

Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.

Nanostructured titanium prepared by the equal-channel angular pressing route (ECAPed Ti) has shown great promise as an implant material over conventional pure titanium. The aim of this report is to investigate its biological properties, surface performance, and comprehensive biological effects at a molecular level when in contact with cells. Protein expression changes of human osteoblast-like MG-63 in response to polished ECAPed Ti had been profiled by employing stable isotope labelling with amino acids in cell culture (SILAC), using cpTi as control after the same polishing process. It was found that ubiquitin proteasome related processes were predominantly enriched in the over-expressed proteins. Superoxide dismutase 2 (SOD2) was apparently up-regulated on the ECAPed Ti surface, which could have contributed to the increase in SOD activity and the decrease in the reactive oxygen species (ROS) level. These expression changes have relationships with protein degradation, bone formation and resistance to oxidative injury, and they suggest that ECAPed Ti has the potential to further promote osteoblast differentiation. On the other hand, the down-regulated proteins exhibited resistance to platelet adhesion on the ECAPed Ti surface. This study reveals the differential expression of proteins in human osteoblasts induced by nanostructured titanium substrates for the first time.
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http://dx.doi.org/10.1039/c3tb00266gDOI Listing
April 2013

Secretome analyses of Aβ(1-42) stimulated hippocampal astrocytes reveal that CXCL10 is involved in astrocyte migration.

J Proteome Res 2013 Feb 15;12(2):832-43. Epub 2013 Jan 15.

National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China.

Amyloid-beta (Aβ) aggregation plays an important role in the development of Alzheimer's disease (AD). In the AD brain, amyloid plaques are surrounded by reactive astrocytes, and many essential functions of astrocytes have been reported to be mediated by protein secretion. However, the roles of activated astrocytes in AD progression are under intense debate. To provide an in-depth view of the secretomes of activated astrocytes, we present in this study a quantitative profile of rat hippocampal astrocyte secretomes at multiple time points after both brief and sustained Aβ(1-42) stimulation. Using SILAC labeling and LC-MS/MS analyses, we identified 19 up-regulated secreted proteins after Aβ(1-42) treatment. These differentially expressed proteins have been suggested to be involved in key aspects of biological processes, such as cell recruitment, Aβ clearance, and regulation of neurogenesis. Particularly, we validated the role played by CXCL10 in promoting astrocyte aggregation around amyloid plagues through in vitro cell migration analysis. This research provides global, quantitative profiling of astrocyte secretomes produced on Aβ stimulation and hence provides a detailed molecular basis for the relationship between amyloid plaques and astrocyte aggregation; the findings thus have important implications for further investigations into AD development and therapy.
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http://dx.doi.org/10.1021/pr300895rDOI Listing
February 2013

Quantitative proteomic analysis of human osteoblast-like MG-63 cells in response to bioinert implant material titanium and polyetheretherketone.

J Proteomics 2012 Jun 29;75(12):3560-73. Epub 2012 Mar 29.

Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.

Commercially pure titanium (cpTi) and polyetheretherketone (PEEK) are widely used surface-modified implant materials in orthopedics and dental therapeutics. However, there still has not been comprehensive biocompatibility evaluation of them at molecular level. By employing stable isotope labeling with amino acids in cell culture (SILAC), we profiled the dynamic protein expression changes in human osteoblast-like MG-63 cells cultured on cpTi and PEEK, respectively. About 2000 proteins were quantified and 400 proteins showed substantial alterations in expression levels upon each material treatment. Notably, the extent of alterations diminished as the contact prolonged, which suggested adaptive response to the bioinert materials. Similar patterns of expression changes were observed for both cpTi and PEEK. The representative pathways reflected the regulation of biosynthesis, metabolism and cell adhesion in the adaptive process. In addition, PEEK showed stronger inhibition on mRNA processing, which explained the lower proliferation rate of the cells cultured on PEEK. Our results indicated that the widely used bioinert materials cpTi and PEEK could individually induce a cooperative response involving a wide panel of proteins and pathways. This study has established a basis for better understanding the biocompatibility of surface-modified implant biomaterials at molecular level.
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http://dx.doi.org/10.1016/j.jprot.2012.03.033DOI Listing
June 2012