Publications by authors named "Peng R Chen"

109 Publications

Chemical engineering of bacterial effectors for regulating cell signaling and responses.

Curr Opin Chem Biol 2021 May 13;64:48-56. Epub 2021 May 13.

College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China. Electronic address:

Bacteria have evolved a variety of effector proteins to facilitate their survival and proliferation within the host environment. Continuous competition at the host-pathogen interface has empowered these effectors with unique mechanism and high specificity toward their host targets. The rich repertoire of bacterial effectors has thus provided us an attractive toolkit for investigating various cellular processes, such as signal transductions. With recent advances in protein chemistry and engineering, we now have the capability for on-demand control of protein activity with high precision. Herein, we review the development of chemically engineered bacterial effectors to control kinase-mediated signal transductions, inhibit protein translation, and direct genetic editing within host cells. We also highlight future opportunities for harnessing diverse prokaryotic effectors as powerful tools for mechanistic investigation and therapeutic intervention of eukaryotic systems.
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http://dx.doi.org/10.1016/j.cbpa.2021.04.003DOI Listing
May 2021

A far-red hybrid voltage indicator enabled by bioorthogonal engineering of rhodopsin on live neurons.

Nat Chem 2021 May 15;13(5):472-479. Epub 2021 Apr 15.

College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China.

Membrane potential is a key aspect of cellular signalling and is dynamically regulated by an array of ion-selective pumps and channels. Fluorescent voltage indicators enable non-invasive optical recording of the cellular membrane potential with high spatial resolution. Here, we report a palette of bright and sensitive hybrid voltage indicators (HVIs) with fluorescence intensities sensitive to changes in membrane potential via electrochromic Förster resonance energy transfer. Enzyme-mediated site-specific incorporation of a probe, followed by an inverse-electron-demand Diels-Alder cycloaddition, was used to create enhanced voltage-sensing rhodopsins with hybrid dye-protein architectures. The most sensitive indicator, HVI-Cy3, displays high voltage sensitivity (-39% ΔF/F per 100 mV) and millisecond response kinetics, enabling optical recording of action potentials at a sampling rate of 400 Hz over 10 min across a large neuronal population. The far-red indicator HVI-Cy5 could be paired with optogenetic actuators and green/red-emitting fluorescent indicators, allowing an all-optical investigation of neuronal electrophysiology.
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http://dx.doi.org/10.1038/s41557-021-00641-1DOI Listing
May 2021

Selective Endothelial Hyperactivation of Oncogenic KRAS Induces Brain Arteriovenous Malformations in Mice.

Ann Neurol 2021 05 22;89(5):926-941. Epub 2021 Mar 22.

Vivian L. Smith Department of Neurosurgery, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX.

Objective: Brain arteriovenous malformations (bAVMs) are a leading cause of hemorrhagic stroke and neurological deficits in children and young adults, however, no pharmacological intervention is available to treat these patients. Although more than 95% of bAVMs are sporadic without family history, the pathogenesis of sporadic bAVMs is largely unknown, which may account for the lack of therapeutic options. KRAS mutations are frequently observed in cancer, and a recent unprecedented finding of these mutations in human sporadic bAVMs offers a new direction in the bAVM research. Using a novel adeno-associated virus targeting brain endothelium (AAV-BR1), the current study tested if endothelial KRAS mutation induces sporadic bAVMs in mice.

Methods: Five-week-old mice were systemically injected with either AAV-BR1-GFP or -KRAS . At 8 weeks after the AAV injection, bAVM formation and characteristics were addressed by histological and molecular analyses. The effect of MEK/ERK inhibition on KRAS -induced bAVMs was determined by treatment of trametinib, a US Food and Drug Administration (FDA)-approved MEK/ERK inhibitor.

Results: The viral-mediated KRAS overexpression induced bAVMs, which were composed of a tangled nidus mirroring the distinctive morphology of human bAVMs. The bAVMs were accompanied by focal angiogenesis, intracerebral hemorrhages, altered vascular constituents, neuroinflammation, and impaired sensory/cognitive/motor functions. Finally, we confirmed that bAVM growth was inhibited by trametinib treatment.

Interpretation: Our innovative approach using AAV-BR1 confirms that KRAS mutations promote bAVM development via the MEK/ERK pathway, and provides a novel preclinical mouse model of bAVMs which will be useful to develop a therapeutic strategy for patients with bAVM. ANN NEUROL 2021;89:926-941.
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http://dx.doi.org/10.1002/ana.26059DOI Listing
May 2021

Integrated Stroke System Model Expands Availability of Endovascular Therapy While Maintaining Quality Outcomes.

Stroke 2021 Mar 4;52(3):1022-1029. Epub 2021 Feb 4.

Department of Neurology (V.L.-R., S.S.-M., R.A., S.I.S., A.L.C., Y.J.A., G.S., T.-C.W., L.D.M., S.A.S.), UTHealth McGovern Medical School, Houston, TX.

Background And Purpose: The optimal endovascular stroke therapy (EVT) care delivery structure is unknown. Here, we present our experience in creating an integrated stroke system (ISS) to expand EVT availability throughout our region while maintaining hospital and physician quality standards.

Methods: We identified all consecutive patients with large vessel occlusion acute ischemic stroke treated with EVT from January 2014 to February 2019 in our health care system. In October 2017, we implemented the ISS, in which 3 additional hospitals (4 total) became EVT-performing hospitals (EPHs) and physicians were rotated between all centers. The cohort was divided by time into pre-ISS and post-ISS, and the primary outcome was time from stroke onset to EPH arrival. Secondary outcomes included hospital and procedural quality metrics. We performed an external validation using data from the Southeast Texas Regional Advisory Council.

Results: Among 513 patients with large vessel occlusion acute ischemic stroke treated with EVT, 58% were treated pre-ISS and 43% post-ISS. Over the study period, EVT procedural volume increased overall but remained relatively low at the 3 new EPHs (<70 EVT/y). After ISS, the proportion of patients who underwent interhospital transfer decreased (46% versus 37%; <0.05). In adjusted quantile regression, ISS implementation resulted in a reduction of time from stroke onset to EPH arrival by 40 minutes (<0.01) and onset to groin puncture by 29 minutes (<0.05). Rates of postprocedural hemorrhage, modified Thrombolysis in Cerebral Infarction (TICI) 2b/3, and 90-day modified Rankin Scale were comparable at the higher and lower volume EPHs. The improvement in onset-to-arrival time was not reflective of overall improvement in secular trends in regional prehospital care.

Conclusions: In our system, increasing EVT availability decreased time from stroke onset to EPH arrival. The ISS provides a framework to maintain quality in lower volume hospitals.
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http://dx.doi.org/10.1161/STROKEAHA.120.032710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902449PMC
March 2021

Genetically encoded formaldehyde sensors inspired by a protein intra-helical crosslinking reaction.

Nat Commun 2021 01 25;12(1):581. Epub 2021 Jan 25.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China.

Formaldehyde (FA) has long been considered as a toxin and carcinogen due to its damaging effects to biological macromolecules, but its beneficial roles have been increasingly appreciated lately. Real-time monitoring of this reactive molecule in living systems is highly desired in order to decipher its physiological and/or pathological functions, but a genetically encoded FA sensor is currently lacking. We herein adopt a structure-based study of the underlying mechanism of the FA-responsive transcription factor HxlR from Bacillus subtilis, which shows that HxlR recognizes FA through an intra-helical cysteine-lysine crosslinking reaction at its N-terminal helix α1, leading to conformational change and transcriptional activation. By leveraging this FA-induced intra-helical crosslinking and gain-of-function reorganization, we develop the genetically encoded, reaction-based FA sensor-FAsor, allowing spatial-temporal visualization of FA in mammalian cells and mouse brain tissues.
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http://dx.doi.org/10.1038/s41467-020-20754-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835342PMC
January 2021

Severe Acute Respiratory Syndrome Coronavirus-2 Spike Protein Nanogel as a Pro-Antigen Strategy with Enhanced Protective Immune Responses.

Small 2020 11 26;16(46):e2004237. Epub 2020 Oct 26.

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

Prevention and intervention methods are urgently needed to curb the global pandemic of coronavirus disease-19 caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Herein, a general pro-antigen strategy for subunit vaccine development based on the reversibly formulated receptor binding domain of SARS-CoV-2 spike protein (S-RBD) is reported. Since the poor lymph node targeting and uptake of S-RBD by antigen-presenting cells prevent effective immune responses, S-RBD protein is formulated into a reversible nanogel (S-RBD-NG), which serves as a pro-antigen with enhanced lymph node targeting and dendritic cell and macrophage accumulation. Synchronized release of S-RBD monomers from the internalized S-RBD-NG pro-antigen triggers more potent immune responses in vivo. In addition, by optimizing the adjuvant used, the potency of S-RBD-NG is further improved, which may provide a generally applicable, safer, and more effective strategy for subunit vaccine development against SARS-CoV-2 as well as other viruses.
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http://dx.doi.org/10.1002/smll.202004237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7645880PMC
November 2020

Treatment trends and overall survival in patients with grade II/III ependymoma: The role of tumor grade and location.

Clin Neurol Neurosurg 2020 12 6;199:106282. Epub 2020 Oct 6.

Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, USA; Memorial Hermann Hospital-Texas Medical Center, Houston, TX, USA; Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, USA. Electronic address:

Background: Treatment of ependymoma (EPN) is guided by associated tumor features, such as grade and location. However, the relationship between these features with treatments and overall survival in EPN patients remains uncharacterized. Here, we describe the change over time in treatment strategies and identify tumor characteristics that influence treatment and survival in EPN.

Methods And Materials: Using the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 18 Registries (1973-2016) database, we identified patients with EPN microscopically confirmed to be grade II (EPN-GII) or III (EPN-GIII) tumors between 2004-2016. Overall survival (OS) was analyzed using Kaplan-Meier survival estimates and multivariable Cox proportional hazard models. A sub-analysis was performed by tumor location (supratentorial, posterior fossa, and spine). Change over time in rates of gross total resection (GTR), radiotherapy (RT), and chemotherapy (CS) were analyzed using linear regression, and predictors of treatment were identified using multivariable logistic regression models.

Results: Between 2004-2016, 1,671 patients were diagnosed with EPN, of which 1,234 (74 %) were EPN-GII and 437 (26 %) EPN-GIII. Over the study period, EPN-GII patients underwent a less aggressive treatment (48 % vs 27 %, GTR; 60 % vs 30 %, RT; 22 % vs 2%, CS; 2004 vs 2016; p < 0.01 for all). Age, tumor size, location, and grade were positive predictors of undergoing treatment. Univariate analysis revealed that tumor grade and location were significantly associated with OS (p < 0.0001 for both). In multivariable Cox regression, tumor grade was an independent predictor of OS among patients in the cohort (grade III, HR 3.89 [2.84-5.33]; p < 0.0001), with this finding remaining significant across all tumor locations.

Conclusions: In EPN, tumor grade and location are predictors of treatment and overall survival. These findings support the importance of histologic WHO grade and location in the decision-making for treatment and their role in individualizing treatment for different patient populations.
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http://dx.doi.org/10.1016/j.clineuro.2020.106282DOI Listing
December 2020

Impact of Initial Imaging Protocol on Likelihood of Endovascular Stroke Therapy.

Stroke 2020 10 3;51(10):3055-3063. Epub 2020 Sep 3.

Department of Neurology (V.L.-R., R.A., S.I.S., A.L.C., Y.A., G.S., T.-C.W., L.D.M., S.A.S.).

Background And Purpose: Noncontrast head CT and CT perfusion (CTP) are both used to screen for endovascular stroke therapy (EST), but the impact of imaging strategy on likelihood of EST is undetermined. Here, we examine the influence of CTP utilization on likelihood of EST in patients with large vessel occlusion (LVO).

Methods: We identified patients with acute ischemic stroke at 4 comprehensive stroke centers. All 4 hospitals had 24/7 CTP and EST capability and were covered by a single physician group (Neurology, NeuroIntervention, NeuroICU). All centers performed noncontrast head CT and CT angiography in the initial evaluation. One center also performed CTP routinely with high CTP utilization (CTP-H), and the others performed CTP optionally with lower utilization (CTP-L). Primary outcome was likelihood of EST. Multivariable logistic regression was used to determine whether facility type (CTP-H versus CTP-L) was associated with EST adjusting for age, prestroke mRS, National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, LVO location, time window, and intravenous tPA (tissue-type plasminogen activator).

Results: Among 3107 patients with acute ischemic stroke, 715 had LVO, of which 403 (56%) presented to CTP-H and 312 (44%) presented to CTP-L. CTP utilization among LVO patients was greater at CTP-H centers (72% versus 18%, CTP-H versus CTP-L, <0.01). In univariable analysis, EST rates for patients with LVO were similar between CTP-H versus CTP-L (46% versus 49%). In multivariable analysis, patients with LVO were less likely to undergo EST at CTP-H (odds ratio, 0.59 [0.41-0.85]). This finding was maintained in multiple patient subsets including late time window, anterior circulation LVO, and direct presentation patients. Ninety-day functional independence (odds ratio, 1.04 [0.70-1.54]) was not different, nor were rates of post-EST PH-2 hemorrhage (1% versus 1%).

Conclusions: We identified an increased likelihood for undergoing EST in centers with lower CTP utilization, which was not associated with worse clinical outcomes or increased hemorrhage. These findings suggest under-treatment bias with routine CTP.
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http://dx.doi.org/10.1161/STROKEAHA.120.030122DOI Listing
October 2020

Cationic Lipid-based Intracellular Delivery of Bacterial Effectors for Rewiring Malignant Cell Signaling.

Angew Chem Int Ed Engl 2020 10 18;59(41):18087-18094. Epub 2020 Aug 18.

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

The abundance of bacterial effectors have inspired us to explore their potential in rewiring malignant cell signaling. Their incapability for entering cells, however, hinders such application. Herein we developed a cationic lipid-based high throughput library screening platform for effective intracellular delivery of bacterial effectors. As the misregulated MAPK signaling is a hallmark of many types of cancer, we turned to the Shigella effector OspF which irreversibly inactivates ERK, the terminal component of MAPK cascade. We created a function-based screening assay to obtain AMPA-O16B lipid nanoparticles for effective OspF intracellular delivery, which inhibited the malignant MAPK signaling and tumor growth in vitro and in vivo. Furthermore, the optimized lipid nanoparticle formulation can deliver OspF to modulate the immunosuppressive responses in macrophages. Our work is a general strategy to explore the therapeutic potentials of naturally evolved bacterial effectors.
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http://dx.doi.org/10.1002/anie.202009572DOI Listing
October 2020

Intellectual disability-associated gene ftsj1 is responsible for 2'-O-methylation of specific tRNAs.

EMBO Rep 2020 08 18;21(8):e50095. Epub 2020 Jun 18.

School of Life Science and Technology, ShanghaiTech University, Shanghai, China.

tRNA modifications at the anti-codon loop are critical for accurate decoding. FTSJ1 was hypothesized to be a human tRNA 2'-O-methyltransferase. tRNA (GAA) from intellectual disability patients with mutations in ftsj1 lacks 2'-O-methylation at C32 and G34 (Cm32 and Gm34). However, the catalytic activity, RNA substrates, and pathogenic mechanism of FTSJ1 remain unknown, owing, in part, to the difficulty in reconstituting enzymatic activity in vitro. Here, we identify an interacting protein of FTSJ1, WDR6. For the first time, we reconstitute the 2'-O-methylation activity of the FTSJ1-WDR6 complex in vitro, which occurs at position 34 of specific tRNAs with m G37 as a prerequisite. We find that modifications at positions 32, 34, and 37 are interdependent and occur in a hierarchical order in vivo. We also show that the translation efficiency of the UUU codon, but not the UUC codon decoded by tRNA (GAA), is reduced in ftsj1 knockout cells. Bioinformatics analysis reveals that almost 40% of the high TTT-biased genes are related to brain/nervous functions. Our data potentially enhance our understanding of the relationship between FTSJ1 and nervous system development.
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http://dx.doi.org/10.15252/embr.202050095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403668PMC
August 2020

Genetically encoded protein labeling and crosslinking in living Pseudomonas aeruginosa.

Bioorg Med Chem 2020 06 6;28(12):115545. Epub 2020 May 6.

Beijing National Laboratory for Molecular Sciences, Synthetic and Functional Biomolecules Center, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Beijing 100871, China. Electronic address:

Pseudomonas aeruginosa (PA) is a major human pathogen for hospital-acquired infections. We report the genetic code expansion of this opportunistic pathogen by using the pyrrolysyl-tRNA synthetase-tRNA system, which enabled the genetic and site-specific incorporation of unnatural amino acids bearing bioorthogonal handles or photo-affinity groups into proteins in PA. This strategy allowed us to conduct bioorthogonal labeling and imaging of flagella, as well as site-specific photo-affinity capturing of interactions between a Type III secretion effector and its chaperone inside living bacteria.
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http://dx.doi.org/10.1016/j.bmc.2020.115545DOI Listing
June 2020

SFPQ Is an FTO-Binding Protein that Facilitates the Demethylation Substrate Preference.

Cell Chem Biol 2020 03 24;27(3):283-291.e6. Epub 2020 Jan 24.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Beijing 100871, China. Electronic address:

The fat mass and obesity-associated protein (FTO) is the first identified demethylase of the internal RNA modification N-methyladenosine (mA), which also exhibits demethylation activity toward N,2'-O-dimethyladenosine (mA) and N-methyladenosine (mA). Demethylation of mA at specific sites on target transcripts is a key enzymatic function of FTO that modulates diverse physiological and/or pathological processes. However, how FTO selects target RNA and whether additional interaction proteins facilitate this process remain elusive. Herein, via the genetically encoded and site-specific photocrosslinking strategy, we identified the major RNA-binding protein SFPQ as a direct interaction partner of FTO. Our study showed that FTO and SFPQ were located in close proximity throughout the transcriptome and that overexpression of SFPQ led to the demethylation of adjacent mAs, likely through recruiting FTO to these specific RNA sites. These results uncovered a new layer of regulation mechanism that may assist FTO to gain substrate specificity.
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http://dx.doi.org/10.1016/j.chembiol.2020.01.002DOI Listing
March 2020

Optimizing Patient Selection for Endovascular Treatment in Acute Ischemic Stroke (SELECT): A Prospective, Multicenter Cohort Study of Imaging Selection.

Ann Neurol 2020 03 21;87(3):419-433. Epub 2020 Jan 21.

Department of Neurology, Stanford University, Stanford, CA.

Objective: The primary imaging modalities used to select patients for endovascular thrombectomy (EVT) are noncontrast computed tomography (CT) and CT perfusion (CTP). However, their relative utility is uncertain. We prospectively assessed CT and CTP concordance/discordance and correlated the imaging profiles on both with EVT treatment decisions and clinical outcomes.

Methods: A phase 2, multicenter, prospective cohort study of large-vessel occlusions presented up to 24 hours from last known well was conducted. Patients received a unified prespecified imaging evaluation (CT, CT angiography, and CTP with Rapid Processing of Perfusion and Diffusion software mismatch determination). The treatment decision, EVT versus medical management, was nonrandomized and at the treating physicians' discretion. An independent, blinded, neuroimaging core laboratory adjudicated favorable profiles based on predefined criteria (CT:Alberta Stroke Program Early CT Score ≥ 6, CTP:regional cerebral blood flow (<30%) < 70ml with mismatch ratio ≥ 1.2 and mismatch volume ≥ 10ml).

Results: Of 4,722 patients screened from January 2016 to February 2018, 361 patients were included. Two hundred eighty-five (79%) received EVT, of whom 87.0% had favorable CTs, 91% favorable CTPs, 81% both favorable profiles, 16% discordant, and 3% both unfavorable. Favorable profiles on the 2 modalities correlated similarly with 90-day functional independence rates (favorable CT = 56% vs favorable CTP = 57%, adjusted odds ratio [aOR] = 1.91, 95% confidence interval [CI] = 0.40-9.01, p = 0.41). Having a favorable profile on both modalities significantly increased the odds of receiving thrombectomy as compared to discordant profiles (aOR = 3.97, 95% CI = 1.97-8.01, p < 0.001). Fifty-eight percent of the patients with favorable profiles on both modalities achieved functional independence as compared to 38% in discordant profiles and 0% when both were unfavorable (p < 0.001 for trend). In favorable CT/unfavorable CTP profiles, EVT was associated with high symptomatic intracranial hemorrhage (sICH) (24%) and mortality (53%) rates.

Interpretation: Patients with favorable imaging profiles on both modalities had higher odds of receiving EVT and high functional independence rates. Patients with discordant profiles achieved reasonable functional independence rates, but those with an unfavorable CTP had higher adverse outcomes. Ann Neurol 2020;87:419-433.
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http://dx.doi.org/10.1002/ana.25669DOI Listing
March 2020

Methylation of PLK1 by SET7/9 ensures accurate kinetochore-microtubule dynamics.

J Mol Cell Biol 2020 07;12(6):462-476

MOE Key Laboratory for Cellular Dynamics & Anhui Key Laboratory for Chemical Biology, CAS Center for Excellence in Molecular Cell Science, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, Hefei 230027, China.

Faithful segregation of mitotic chromosomes requires bi-orientation of sister chromatids, which relies on the sensing of correct attachments between spindle microtubules and kinetochores. Although the mechanisms underlying PLK1 activation have been extensively studied, the regulatory mechanisms that couple PLK1 activity to accurate chromosome segregation are not well understood. In particular, PLK1 is implicated in stabilizing kinetochore-microtubule attachments, but how kinetochore PLK1 activity is regulated to avoid hyperstabilized kinetochore-microtubules in mitosis remains elusive. Here, we show that kinetochore PLK1 kinase activity is modulated by SET7/9 via lysine methylation during early mitosis. The SET7/9-elicited dimethylation occurs at the Lys191 of PLK1, which tunes down its activity by limiting ATP utilization. Overexpression of the non-methylatable PLK1 mutant or chemical inhibition of SET7/9 methyltransferase activity resulted in mitotic arrest due to destabilized kinetochore-microtubule attachments. These data suggest that kinetochore PLK1 is essential for stable kinetochore-microtubule attachments and methylation by SET7/9 promotes dynamic kinetochore-microtubule attachments for accurate error correction. Our findings define a novel homeostatic regulation at the kinetochore that integrates protein phosphorylation and methylation with accurate chromosome segregation for maintenance of genomic stability.
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http://dx.doi.org/10.1093/jmcb/mjz107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333475PMC
July 2020

Blood-Brain Barrier- and Blood-Brain Tumor Barrier-Penetrating Peptide-Derived Targeted Therapeutics for Glioma and Malignant Tumor Brain Metastases.

ACS Appl Mater Interfaces 2019 Nov 29;11(45):41889-41897. Epub 2019 Oct 29.

Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences , Capital Medical University , Beijing 100069 , China.

Glioma is the most common malignant tumor of the central nervous system (CNS). Therapeutic efficacy of glioma treatment is greatly limited by the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB), which restrict the passage of most drugs into the brain and tumors. Developing drug delivery systems that cross the BBB and BBTB will aid in the treatment of glioma and malignant brain metastases. One emerging solution is to identify peptide vectors that penetrate the BBB/BBTB. Herein, a novel BBB/BBTB-penetrating peptide was identified from the phage-displayed peptide library. Peptide-drug conjugates (PDCs) were derived and applied to treat glioma and breast cancer brain metastases. Antitumor activity was achieved in both tumor models with synergistic effects when combined with the currently used chemotherapy drug temozolomide. The peptide reported herein can serve as a universal vector for shuttling compounds across the BBB; therefore, it may have wide applications for treating brain tumors and other CNS diseases.
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http://dx.doi.org/10.1021/acsami.9b14046DOI Listing
November 2019

Copper-Triggered Bioorthogonal Cleavage Reactions for Reversible Protein and Cell Surface Modifications.

J Am Chem Soc 2019 10 16;141(43):17133-17141. Epub 2019 Oct 16.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China.

Temporal and reversible control over protein and cell conjugations holds great potential for traceless release of antibody-drug conjugates (ADCs) on tumor sites as well as on-demand altering or removal of targeting elements on cell surface. We herein developed a bioorthogonal and traceless releasable reaction on proteins and intact cells to fulfill such purposes. A systematic survey of transition metals in catalyzing the bioorthogonal cleavage reactions revealed that copper complexes such as Cu(I)-BTTAA and dual-substituted propargyl (dsPra) or propargyloxycarbonyl (dsProc) moieties offered a bioorthogonal releasable pair for reversible blockage and rescue of primary amines and phenol alcohols on small molecule drugs, protein side chains, as well as intact cell surface. For proof-of-concept, we employed such Cu(I)-BTTAA/dsProc and Cu(I)-BTTAA/dsPra pairs as a "traceless linker" strategy to construct cleavable ADCs to unleash cytotoxic compounds on cancer cells in situ and as a "reversible modification" strategy for cell surface engineering. Furthermore, by coupling with the genetic code expansion strategy, we site-specifically modulated ligand-receptor interactions on live cell membranes. Together, our work expanded the transition-metal-mediated bioorthogonal cleavage tool kit from terminal decaging to internal-linker breakage, which offered a temporal and reversible conjugation strategy on therapeutic proteins and cells.
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http://dx.doi.org/10.1021/jacs.9b05833DOI Listing
October 2019

Dynamic modifications of biomacromolecules: mechanism and chemical interventions.

Sci China Life Sci 2019 Nov 18;62(11):1459-1471. Epub 2019 Sep 18.

College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

Biological macromolecules (proteins, nucleic acids, polysaccharides, etc.) are the building blocks of life, which constantly undergo chemical modifications that are often reversible and spatial-temporally regulated. These dynamic properties of chemical modifications play fundamental roles in physiological processes as well as pathological changes of living systems. The Major Research Project (MRP) funded by the National Natural Science Foundation of China (NSFC)-"Dynamic modifications of biomacromolecules: mechanism and chemical interventions" aims to integrate cross-disciplinary approaches at the interface of chemistry, life sciences, medicine, mathematics, material science and information science with the following goals: (i) developing specific labeling techniques and detection methods for dynamic chemical modifications of biomacromolecules, (ii) analyzing the molecular mechanisms and functional relationships of dynamic chemical modifications of biomacromolecules, and (iii) exploring biomacromolecules and small molecule probes as potential drug targets and lead compounds.
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http://dx.doi.org/10.1007/s11427-019-9823-1DOI Listing
November 2019

Time-resolved protein activation by proximal decaging in living systems.

Nature 2019 05 8;569(7757):509-513. Epub 2019 May 8.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.

A universal gain-of-function approach for selective and temporal control of protein activity in living systems is crucial to understanding dynamic cellular processes. Here we report development of a computationally aided and genetically encoded proximal decaging (hereafter, CAGE-prox) strategy that enables time-resolved activation of a broad range of proteins in living cells and mice. Temporal blockage of protein activity was computationally designed and realized by genetic incorporation of a photo-caged amino acid in proximity to the functional site of the protein, which can be rapidly removed upon decaging, resulting in protein re-activation. We demonstrate the wide applicability of our method on diverse protein families, which enabled orthogonal tuning of cell signalling and immune responses, temporal profiling of proteolytic substrates upon caspase activation as well as the development of protein-based pro-drug therapy. We envision that CAGE-prox will open opportunities for the gain-of-function study of proteins and dynamic biological processes with high precision and temporal resolution.
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http://dx.doi.org/10.1038/s41586-019-1188-1DOI Listing
May 2019

Intraarterial Thrombolysis as Rescue Therapy for Large Vessel Occlusions.

Stroke 2019 04;50(4):1003-1006

Wellstar Health Systems, Marietta, GA (R.G.).

Background and Purpose- Mechanical thrombectomy (MT) devices have led to improved reperfusion and clinical outcomes in acute ischemic stroke patients with emergent large vessel occlusions; however, less than one-third of patients achieve complete reperfusion. Use of intraarterial thrombolysis in the context of MT may provide an opportunity to enhance these results. Here, we evaluate the use of intraarterial rtPA (recombinant tissue-type plasminogen activator) as rescue therapy (RT) after failed MT in the North American Solitaire Stent-Retriever Acute Stroke registry. Methods- The North American Solitaire Stent-Retriever Acute Stroke registry recruited sites within North America to submit data on acute ischemic stroke patients treated with the Solitaire device. After restricting the population of 354 patients to use of RT and anterior emergent large vessel occlusions, we compared patients who were treated with and without intraarterial rtPA after failed MT. Results- A total of 37 and 44 patients was in the intraarterial rtPA RT and the no intraarterial rtPA RT groups, respectively. Revascularization success (modified Thrombolysis in Cerebral Infarction ≥2b) was achieved in more intraarterial rtPA RT patients (61.2% versus 46.6%; P=0.13) with faster times to recanalization (100±85 versus 164±235 minutes; P=0.36) but was not statistically significant. The rate of symptomatic intracranial hemorrhage (13.9% versus 6.8%; P=0.29) and mortality (42.9% versus 44.7%; P=0.87) were similar between the groups. Good functional outcome (modified Rankin Scale score of ≤2) was numerically higher in intraarterial rtPA patients (22.9% versus 18.4%; P=0.64). Further restriction of the RT population to M1 occlusions only and time of onset to groin puncture ≤8 hours, resulted in significantly higher successful revascularization rates in the intraarterial rtPA RT cohort (77.8% versus 38.9%; P=0.02). Conclusions- Intraarterial rtPA as RT demonstrated a similar safety and clinical outcome profile, with higher reperfusion rates achieved in patients with M1 occlusions. Prospective studies are needed to delineate the role of intraarterial thrombolysis in MT.
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http://dx.doi.org/10.1161/STROKEAHA.118.024442DOI Listing
April 2019

Bioorthogonal Engineering of Bacterial Effectors for Spatial-Temporal Modulation of Cell Signaling.

ACS Cent Sci 2019 Jan 27;5(1):145-152. Epub 2018 Dec 27.

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

The complicated and entangled cell signaling network is dynamically regulated by a wide array of enzymes such as kinases. It remains desirable but challenging to specifically modulate individual, endogenous kinases within a cell, particularly in a spatial-temporally controlled fashion. Current strategies toward regulating the intracellular functions of a kinase of interest either lack specificity or require genetic engineering that may perturb its physiological activity. Herein, we harnessed a bacterial effector OspF for optical and chemical modulation of the endogenous mitogen-activated protein kinase (MAPK) cascade in living cells and mice. The phospho-lyase OspF provided high specificity and spatial resolution toward the desired kinase such as the extracellular signal-regulated kinase (ERK), while the genetically encoded bioorthogonal decaging strategy enabled its temporal activation in living systems. The photocaged OspF (OspF*) was applied to dissect the subcellular signaling roles of ERK in nucleus as opposed to cytoplasm, while the chemically caged OspF (OspF) was introduced into living mice to modulate ERK-mediated gene expression. Finally, our spatially and chemically controlled OspF was further used to precisely tune immune responses in T cells. Together, our bioorthogonal engineering strategy on bacterial effectors offers a general tool to modulate cell signaling with high specificity and spatial-temporal resolution.
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http://dx.doi.org/10.1021/acscentsci.8b00751DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6346392PMC
January 2019

Enzyme-Mediated Intercellular Proximity Labeling for Detecting Cell-Cell Interactions.

J Am Chem Soc 2019 02 29;141(5):1833-1837. Epub 2019 Jan 29.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering , Peking University , Beijing , China.

Cell-cell interactions and communications play fundamental roles in life processes but remain largely uncharacterized. We developed an enzyme-mediated proximity cell labeling (EXCELL) strategy as a general method to detect and record cell-cell interactions under living conditions. EXCELL relies on an evolved Staphylococcus aureus transpeptidase sortase A variant (mgSrtA) capable of promiscuous labeling of various cell surface proteins containing a monoglycine residue at the N-terminus. Displaying mgSrtA on the surface of a cell of interest allows the labeling and detection of interacting cells in a proximity-dependent fashion.
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http://dx.doi.org/10.1021/jacs.8b10286DOI Listing
February 2019

A Phase 2 Randomized, Sham-Controlled Trial of Internal Carotid Artery Infusion of Autologous Bone Marrow-Derived ALD-401 Cells in Patients With Recent Stable Ischemic Stroke (RECOVER-Stroke).

Circulation 2019 01;139(2):192-205

Unicorn Pharma Consulting of Brentwood, TN (J.M.H.).

Background: Ischemic stroke has no approved treatments to enhance recovery. ALD-401 is an enriched population of aldehyde dehydrogenase-bright stem cells, capable of reducing neurological deficits in animal models. The primary objective of this trial was to determine the safety of internal carotid artery, intra-arterially delivered autologous bone marrow-derived ALD-401 in patients with disabling middle cerebral artery stroke in comparison with sham harvest with sham infusion. Secondary objectives were to determine feasibility and efficacy.

Methods: This was a prospective phase 2, industry-funded, randomized, sham-controlled, parallel-group, multicenter study with blinded assessments. One hundred subjects were planned, aged 30 to 83 years, with confirmed first-time middle cerebral artery ischemic stroke with modified Rankin scale ≥3. Study patients were randomly assigned 3:2 to bone marrow harvest at 11 to 17 days after stroke followed 2 days later by intracarotid infusion of ALD-401 versus sham harvest and then sham infusion in the same timeframe. The primary study outcome was safety based on the incidence of a 4-point National Institutes of Health Stroke Scale worsening and the proportion of serious adverse events. Efficacy was based on modified Rankin scale change at 90 days. Other secondary outcomes were the proportions of patients experiencing adverse events, disability by Barthel Index, quality of life using EQ-5D, rehabilitation utilization, disability at 1 year, and MRI evidence of complications.

Results: There were no infusional or allergic reactions and no difference in treatment emergent adverse events. Four patients had small areas of asymptomatic restricted diffusion on MRI in the treatment group. There was no significant difference between the ALD-401 and placebo groups on the modified Rankin scale for the intent-to-treat population at day 90 (mean difference, 0.3; 95% CI, -0.3 to 0.8; P=0.330). There were no significant differences between the groups on any of the secondary efficacy measures.

Conclusions: Intracarotid infusion of ALD-401 does not lead to clinical adverse events in patients with subacute ischemic stroke, although there was a higher incidence of small lesions on MRI in the treatment group. There was no difference in the primary efficacy end point between the groups. The study provides a framework for the design and conduct of future intra-arterial cell therapy trials in stroke.

Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01273337.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.117.030659DOI Listing
January 2019

Synergistic enzymatic and bioorthogonal reactions for selective prodrug activation in living systems.

Nat Commun 2018 11 28;9(1):5032. Epub 2018 Nov 28.

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

Adverse drug reactions (ADRs) restrict the maximum doses applicable in chemotherapy, which leads to failure in cancer treatment. Various approaches, including nano-drug and prodrug strategies aimed at reducing ADRs, have been developed, but these strategies have their own pitfalls. A renovated strategy for ADR reduction is urgently needed. Here, we employ an enzymatic supramolecular self-assembly process to accumulate a bioorthogonal decaging reaction trigger inside targeted cancer cells, enabling spatiotemporally controlled, synergistic prodrug activation. The bioorthogonally activated prodrug exhibits significantly enhanced potency against cancer cells compared with normal cells. This prodrug activation strategy further demonstrates high tumour inhibition efficacy with satisfactory biocompatibility, pharmacokinetics, and safety in vivo. We envision that integration of enzymatic and bioorthogonal reactions will serve as a general small-molecule-based strategy for alleviation of ADRs in chemotherapy.
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http://dx.doi.org/10.1038/s41467-018-07490-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6261997PMC
November 2018

Protease-Mediated Protein Quality Control for Bacterial Acid Resistance.

Cell Chem Biol 2019 01 21;26(1):144-150.e3. Epub 2018 Nov 21.

Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China. Electronic address:

The periplasm of food-borne enteric pathogens is perhaps the only internal space of living species that can be severely acidified (pH 1-3), which occurs when these pathogens pass through the acidic human stomach. Whereas the periplasmic chaperoning systems are known to deal with such a harsh unfolding stress, other protein quality control mechanisms remain unexplored. Here we report a protease-mediated degradation mechanism that facilitates bacterial acid resistance. The genetic analysis revealed that mutant in degP encoding an HtrA family serine protease rendered Escherichia coli highly acid vulnerable. Combining genetically encoded trifunctional probe with 2D-based comparative proteomics, we identified its substrates. We further demonstrated that DegP directly bound to diverse aggregation-prone periplasmic proteins upon acid stress and these pre-mixed DegP-substrate co-aggregates were subsequently digested by proteolytic-rescued DegP during acid recovery. DegP represents an unprecedented "acid protease" that maintains protein homeostasis in coping with acid-induced protein unfolding stress within E. coli periplasm.
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http://dx.doi.org/10.1016/j.chembiol.2018.10.014DOI Listing
January 2019

Safety and Feasibility of Argatroban, Recombinant Tissue Plasminogen Activator, and Intra-Arterial Therapy in Stroke (ARTSS-IA Study).

J Stroke Cerebrovasc Dis 2018 Dec 21;27(12):3647-3651. Epub 2018 Sep 21.

Neurology Department, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHSC), Houston, Texas. Electronic address:

Background: A randomized trial of concurrent recombinant tissue-type plasminogen activator (r-tPA) + thrombin-inhibition with Argatroban in stroke patients recently demonstrated safety and signal of efficacy compared to r-tPA alone, but patients having endovascular therapy (EVT) were excluded. The current study intended to study feasibility and safety of concurrent r-tPA and Argatroban in patients undergoing EVT.

Methods: We conducted a single-arm, feasibility, and safety study of patients that received standard-dose r-tPA, had intracranial large vessel occlusions, and underwent EVT within 6 hours of stroke onset. During r-tPA, a 100 μg/kg Argatroban bolus, followed by 12-hour infusion, targeted an activated Partial Thromboplastin Time (aPTT) 2.25 timesbaseline. Feasibility was defined as ability to combine treatments without EVT time-metric delays, compared to cotemporaneous r-tPA + EVT treatments. Safety was incidence of symptomatic intracerebral hemorrhage (sICH), systemic hemorrhage, or EVT complications.

Results: All preplanned 10 patients were enrolled. Arterial occlusions were middle cerebral artery (n = 8), internal carotid artery (n = 1), and posterior cerebral artery (n = 1). All received Argatroban before EVT and completed infusions. There were no delays in time-metrics compared to nonstudy patients during the same period. Nine patients achieved excellent angiographic reperfusion (Thrombolysis In Cerebral Ischemia [TICI] ≥2b); with 7 complete (TICI = 3). There were no sICH, systemic hemorrhage, or EVT complications. At 90 days, 6 (60%) patients had a modified Rankin Scale of 0-2 and none died.

Conclusions: In patients treated with r-tPA and EVT, concomitant Argatroban is feasible, does not delay EVT provision, produces high rates of recanalization, is probably safe, and warrants further study.
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http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2018.08.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6252138PMC
December 2018

North American Solitaire Stent Retriever Acute Stroke registry: post-marketing revascularization and clinical outcome results.

J Neurointerv Surg 2018 Jul;10(Suppl 1):i45-i49

Department of Neurology, Medical College of Wisconsin/Froedtert Hospital, Milwaukee, Wisconsin, USA.

Background: Limited post-marketing data exist on the use of the Solitaire FR device in clinical practice. The North American Solitaire Stent Retriever Acute Stroke (NASA) registry aimed to assess the real world performance of the Solitaire FR device in contrast with the results from the SWIFT (Solitaire with the Intention for Thrombectomy) and TREVO 2 (Trevo versus Merci retrievers for thrombectomy revascularization of large vessel occlusions in acute ischemic stroke) trials.

Methods: The investigator initiated NASA registry recruited North American sites to submit retrospective angiographic and clinical outcome data on consecutive acute ischemic stroke (AIS) patients treated with the Solitaire FR between March 2012 and February 2013. The primary outcome was a Thrombolysis in Myocardial Ischemia (TIMI) score of ≥2 or a Treatment in Cerebral Infarction (TICI) score of ≥2a. Secondary outcomes were 90 day modified Rankin Scale (mRS) score, mortality, and symptomatic intracranial hemorrhage.

Results: 354 patients underwent treatment for AIS using the Solitaire FR device in 24 centers. Mean time from onset to groin puncture was 363.4±239 min, mean fluoroscopy time was 32.9±25.7 min, and mean procedure time was 100.9±57.8 min. TIMI ≥2 rate of 83.3% (315/354) and TICI ≥2a rate of 87.5% (310/354) compared with the operator reported TIMI ≥2 rate of 83% in SWIFT and TICI ≥2a rate of 85% in TREVO 2. 42% (132/315) of NASA patients demonstrated a 90 day mRS ≤2 compared with 37% (SWIFT) and 40% (TREVO 2). 90 day mortality was 30.2% (95/315) versus 17.2% (SWIFT) and 29% (TREVO 2).

Conclusions: The NASA registry demonstrated that the Solitaire FR device performance in clinical practice is comparable with the SWIFT and TREVO 2 trial results.
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http://dx.doi.org/10.1136/neurintsurg-2013-010895.repDOI Listing
July 2018

Optimizing orthogonality.

Nat Chem 2018 08;10(8):802-803

The Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.

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http://dx.doi.org/10.1038/s41557-018-0115-7DOI Listing
August 2018

First Pass Effect: A New Measure for Stroke Thrombectomy Devices.

Stroke 2018 03 19;49(3):660-666. Epub 2018 Feb 19.

From the Neuroscience Institute, Mercy Health St. Vincent Medical Center, Toledo, OH (O.O.Z.); Division of Interventional Neuroradiology, Baptist Cardiac and Vascular Institute, Miami, FL (I.L., G.D.); Neuroscience Center, Wellstar Health System, Atlanta, GA (R.G.); Neurointerventional and Diagnostic Associates, Saint Luke's Hospital, Kansas City, MO (C.O.M, W.E.H.); Department of Neurology, Delray Medical Center, Delray Beach, FL (N.M.-K., R.K.); California Pacific Medical Center, San Francisco (J.D.E.); Alexian Brothers Medical Center, Elk Grove Village, IL (T.W.M., F.A.M.); Oregon Health and Science University, Portland (H.B.); Department of Neurology, Wayne State University School of Medicine, Detroit, MI (A.X.); Department of Radiology, West Virginia University Hospital, Morgantown (A.T.R.); Departments of Neurology, Neurosurgery, and Radiology, Vanderbilt University Medical Center, Nashville, TN (M.T.F.); Department of Neurosurgery, Presence Saint Joseph Medical Center, Joliet, IL (A.B.); Department of Neurology (T.N.N.), Department of Neurosurgery (T.N.N.), and Department of Radiology (T.N.N.), Boston Medical Center, MA; Los Robles Medical Center, Thousand Oaks, CA (M.A.T.); University of Kansas Medical Center, Kansas City (M.G.A.); Texas Stroke Institute, Dallas-Forth Worth (A.J.Y, V.J.); Department of Neurology, University of Texas Medical Branch, Galveston (H.S.); Department of Neurology (R.N.), Department of Neurosurgery (R.N.), and Department of Radiology (R.N.), UT Southwestern Medical Center, Dallas, TX; Baptist Health System, Louisville, KY (A.A.-C.); Department of Neurosurgery, University of Texas Medical School, Houston (P.R.C); Department of Neurosurgery, Methodist Neurological Institute, Houston, TX (G.W.B.); Department of Neurology (C.-H.J.S., R.G.N.), Department of Neurosurgery (C.-H.J.S., R.G.N.), and Department of Radiology (C.-H.J.S., R.G.N.), Emory University School of Medicine, Atlanta, GA; and SSM Health, St. Louis, MO (A.N.).

Background And Purpose: In acute ischemic stroke, fast and complete recanalization of the occluded vessel is associated with improved outcomes. We describe a novel measure for newer generation devices: the first pass effect (FPE). FPE is defined as achieving a complete recanalization with a single thrombectomy device pass.

Methods: The North American Solitaire Acute Stroke Registry database was used to identify a FPE subgroup. Their baseline features and clinical outcomes were compared with non-FPE patients. Clinical outcome measures included 90-days modified Rankin Scale score, National Institutes of Health Stroke Scale score, mortality, and symptomatic intracranial hemorrhage. Multivariate analyses were performed to determine whether FPE independently resulted in improved outcomes and to identify predictors of FPE.

Results: A total of 354 acute ischemic stroke patients underwent thrombectomy in the North American Solitaire Acute Stroke registry. FPE was achieved in 89 out of 354 (25.1%). More middle cerebral artery occlusions (64% versus 52.5%) and fewer internal carotid artery occlusions (10.1% versus 27.7%) were present in the FPE group. Balloon guide catheters were used more frequently with FPE (64.0% versus 34.7%). Median time to revascularization was significantly faster in the FPE group (median 34 versus 60 minutes; =0.0003). FPE was an independent predictor of good clinical outcome (modified Rankin Scale score ≤2 was seen in 61.3% in FPE versus 35.3% in non-FPE cohort; =0.013; odds ratio, 1.7; 95% confidence interval, 1.1-2.7). The independent predictors of achieving FPE were use of balloon guide catheters and non-internal carotid artery terminus occlusion.

Conclusions: The achievement of complete revascularization from a single Solitaire thrombectomy device pass (FPE) is associated with significantly higher rates of good clinical outcome. The FPE is more frequently associated with the use of balloon guide catheters and less likely to be achieved with internal carotid artery terminus occlusion.
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http://dx.doi.org/10.1161/STROKEAHA.117.020315DOI Listing
March 2018

Genetic Code Expansion in Enteric Bacterial Pathogens.

Methods Mol Biol 2018 ;1728:113-126

Peking-Tsinghua Center for Life Sciences, Beijing, China.

The genetic code expansion strategy has become an elegant method for site-specific incorporation of noncanonical amino acids with diverse functionalities into proteins of interest in bacteria, yeast, mammalian cells, and even animals. This technique allows precise labeling as well as manipulation of a given protein to dissect its physiological and/or pathological roles under living conditions. Here, we demonstrate the extension of a recently emerged pyrrolysine-based genetic code expansion strategy for encoding noncanonical amino acids into enteric bacterial pathogens.
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http://dx.doi.org/10.1007/978-1-4939-7574-7_6DOI Listing
December 2018