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1.
Nat Rev Neurol ; 2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-32203399

RESUMO

Most neurodegenerative diseases are characterized by the intracellular or extracellular aggregation of misfolded proteins such as amyloid-ß and tau in Alzheimer disease, α-synuclein in Parkinson disease, and TAR DNA-binding protein 43 in amyotrophic lateral sclerosis. Accumulating evidence from both human studies and disease models indicates that intercellular transmission and the subsequent templated amplification of these misfolded proteins are involved in the onset and progression of various neurodegenerative diseases. The misfolded proteins that are transferred between cells are referred to as 'pathological seeds'. Recent studies have made exciting progress in identifying the characteristics of different pathological seeds, particularly those isolated from diseased brains. Advances have also been made in our understanding of the molecular mechanisms that regulate the transmission process, and the influence of the host cell on the conformation and properties of pathological seeds. The aim of this Review is to summarize our current knowledge of the cell-to-cell transmission of pathological proteins and to identify key questions for future investigation.

2.
Cell Rep ; 30(12): 4152-4164.e6, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32209475

RESUMO

Histone methyl groups can be removed by demethylases. Although LSD1 and JmjC domain-containing proteins have been identified as histone demethylases, enzymes for many histone methylation states or sites are still unknown. Here, we perform a screening of a cDNA library containing 2,500 nuclear proteins and identify hHR23A as a histone H4K20 demethylase. Overexpression of hHR23A reduces the levels of H4K20me1/2/3 in cells. In vitro, hHR23A specifically demethylates H4K20me1/2/3 and generates formaldehyde. The enzymatic activity requires Fe(II) and α-ketoglutarate as cofactors and the UBA domains of hHR23A. hHR23B, a protein homologous to hHR23A, also demethylates H4K20me1/2/3 in vitro and in vivo. We further demonstrate that hHR23A/B activate the transcription of coding genes by demethylating H4K20me1 and the transcription of repetitive elements by demethylating H4K20me3. Nuclear magnetic resonance (NMR) analyses demonstrate that an HxxxE motif in the UBA1 domain is crucial for iron binding and demethylase activity. Thus, we identify two hHR23 proteins as histone demethylases.

3.
Sci Total Environ ; 719: 137483, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32120102

RESUMO

The light absorption of brown carbon (BrC) makes a significant contribution to aerosol light absorption (Abs) and affects the radiative forcing. In this study, we analyzed and evaluated the light absorption and radiative forcing of BrC samples collected from December 2016 to January 2017 in Chongqing and Chengdu in the Sichuan Basin of Southwest China. Based on a two-component model, we estimated that BrC light absorption at 405 nm was 19.9 ± 17.1 Mm-1 and 19.2 ± 12.3 Mm-1 in Chongqing and Chengdu, contributing 19.0 ± 5.0% and 17.8 ± 3.7% to Abs respectively. Higher Abs405,BrC, MAE405,BrC, and AAE405-980 values were observed during the pollution period over the clean period in both cities. The major sources of BrC were biomass burning (BB) and secondary organic aerosol in Chongqing, and coal combustion (CC) and secondary organic aerosol in Chengdu. During the pollution period, aged BrC formed from anthropogenic precursors via its aqueous reactions with NH4+ and NOx had impacts on BrC absorption in both cities. BB led to higher Abs405,BrC, MAE405,BrC, and AAE405-980 values in Chongqing than Chengdu during the pollution period. The fractional contribution of radiation absorbed by BrC relative to BC in the wavelengths of 405-445 nm was 60.2 ± 17.0% and 64.2 ± 11.6% in Chongqing and Chengdu, significantly higher than that in the range of 405-980 nm (26.2 ± 6.7% and 27.7 ± 4.6% respectively) (p < 0.001). This study is useful for understanding the characterization, sources, and impacts of BrC in the Sichuan Basin.

4.
Chemosphere ; 252: 126425, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32197172

RESUMO

Environmentally persistent free radicals (EPFRs) are a novel class of hazardous substances that can exist stably in airborne particles for a period ranging from days to weeks and are potentially toxic to human health. Electron paramagnetic resonance spectroscopy (EPR) was used to characterize particulate EPFRs in Wanzhou in the Three Gorges Reservoir area in 2017. During the whole of 2017, the average concentration of particulate EPFRs was 7.0 × 1013 ± 1.7 × 1013 spins/m3. The seasonal concentration of EPFRs in PM2.5 showed a trend of autumn > winter > spring > summer. The maxima and minima of EPFRs occurred in spring with concentrations of 2.1 × 1014 spins/m3 and 9.4 × 1012 spins/m3 respectively. The EPFRs in PM2.5 were mainly carbon-centered radicals with adjacent oxygen atoms. Significant positive correlations were found between EPFRs and SO42-, NO3- and NH4+ (r > 0.55, n = 111), indicating that EPFRs are associated with secondary sources. The atmospheric processing of particles from coal combustion, traffic, and agriculture were important sources of EPFRs. They were also particularly well correlated with K+ and Cl- in winter, suggesting that EPFRs may also be derived from wintertime biomass burning emissions. The amount of inhalable EPFRs in Wanzhou was equivalent to the range of 2.3-6.8 cigarettes per capita per day. This study provides evidence of the potential health risks of EPFRs in PM2.5, and references for air pollution control in the Three Gorges Reservoir area.

5.
Endocrine ; 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32162186

RESUMO

OBJECTIVE: The aim of this study was to evaluate the long-term outcomes of initial Gamma Knife radiosurgery (GKRS) for patients with nonfunctioning pituitary adenomas (NFPAs). DESIGN AND METHODS: This was a single-center retrospective study. Eighty-one patients with NFPAs undergoing initial GKRS were enrolled. The median age was 44.9 years (range, 7.2-75.5 years). The median tumor volume was 2.3 cm3 (range, 0.1-31.3 cm3), and the median tumor margin dose was 13.0 Gy (range, 8-22 Gy). RESULTS: Tumor shrunk in 63 patients (77.8%), remained stable in 9 (11.1%), treatment failure in 9 (11.1%) during a median follow-up of 67.1 months (range, 11.5-263.9 months). The tumor control rates were 100%, 99%, 95%, and 84%, at 1, 3, 5, and 10 years, respectively. In multivariate analysis, tumor volume (≥4 cm3) and margin dose (<12 Gy) were associated with treatment failure (hazard ratio (HR) = 7.093, 95% confidence interval (CI) = 1.098-45.083, p = 0.040, and HR = 9.643, 95% CI = 1.108-83.927, p = 0.040, respectively). New apoplexy occurred in seven patients (8.6%) after GKRS with a median time of 39.9 months (range, 11.9-166.8 months). In multivariate analysis, tumor volume (≥10 cm3) was a significant risk factor (HR = 10.642, 95% CI = 2.121-53.398, p = 0.004). New hypopituitarism occurred in 14 patients (17.3%). No factors were associated with new hypopituitarism. Four patients (4.9%) developed new or worsening visual dysfunction. No new cranial neuropathy was noted. CONCLUSIONS: In this study, initial GKRS can provide a high tumor control rate, as well as a low incidence rate of complications in NFPAs. GKRS may be an alternative initial treatment for selected NFPAs.

6.
ACS Chem Biol ; 15(3): 632-639, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32069008

RESUMO

Post-translational modifications play vital roles in fine-tuning a myriad of physiological processes, and one of the most important modifications is acetylation. Here, we report a ligand-directed site-selective acetylation using KHAc, a derivative of a phosphoglycerate mutase 1 (PGAM1) inhibitor. KHAc binds to PGAM1 and transfers its acetyl group to the ε-NH2 of Lys100 to inactivate the enzyme. The acetyl transfer process was visualized by time-resolved crystallography, demonstrating that the transfer is driven by proximity effects. KHAc was capable of selectively and effectively acetylating Lys100 of PGAM1 in cultured human cells, accompanied by inhibited F-actin formation. Similar strategies could be used for exogenous control of other lysine post-translational modifications.

7.
J Chromatogr A ; : 460913, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-32007220

RESUMO

Traditional boron affinity materials usually capture cis-diol-containing molecules under alkaline condition, but some cis-diol-containing molecules, such as polyphenols, are unstable and easy to be oxidized and degraded under alkaline condition. Teamed boronate affinity (TBA) can specifically capture cis-diol-containing molecules under neutral condition. However, the report about combination of TBA and magnetic nanoparticle for the extraction was rare. Here, we fabricated two kinds of teamed boronate affinity magnetic nanoparticles (TBAMP), including Fe3O4@TBAP and Fe3O4@SiO2@TBAP. Adsorption capacities of cis-diol-containing molecules on the latter were similar to these on the former, but the latter possessed more superior regeneration performance than the former. Therefore, the TBAMP with more superior regeneration performance was used as magnetic solid-phase extraction (MSPE) adsorbent for capturing polyphenols under neutral condition. The TBAMP MSPE was optimized in detail, and combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the simultaneous determination of 13 kinds of polyphenols from Flos Lonicerae Beverage. The proposed method showed low limit of detection between 0.01 and 0.20 ng mL-1. In blank Flos Lonicerae Beverage, 11 kinds of polyphenols ranged from 0.54 ng mL-1 to 52.99 ng mL-1 were detected. In the standard addition method, recoveries of cis-diol-containing polyphenols were between 85.7% and 102.1% with intra-day and inter-day relative standard deviation ranging from 3.2% to 5.1% and 5.3% to 7.3%, respectively.

8.
Macromol Rapid Commun ; 41(6): e1900583, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32009279

RESUMO

A unique cuboid spider silk from the outer egg sac of Nephila pilipes, with an unusual square cross-section, is disclosed. The structure-function relationships within this silk are first studied through structural characterization, mechanical measurement, protein conformation, and polypeptide signature of silk proteins. This silk maintains the higher stiffness property of egg sac silks, and also shows a species difference. Environmental response of the mechanical properties within this silk are observed. Synchrotron FTIR microspectroscopy is used to monitor the silk protein conformation in a single natural silk. The ß-sheet structure aligns parallel to the fiber axis with a content of 22% ± 2.6%. The de novo resulting polypeptide from the solid silk fibers are novel, and an abundant polar amino acid insertion is observed. Short polyalanine (An , n ≤ 3), alternating serine and alanine (S/A)X, and alternating glycine and alanine (G/A)X, GGX, and SSX dominates in the resulting de novo polypeptide. This accords with the composition pattern of other egg sac silk proteins, besides the rarely observed GGX. This study broadens the library of egg sac spider silks and provides a new perspective to uncover structure-function relationships in spider silk.

9.
J Orthop Sci ; 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32061466

RESUMO

PURPOSE: The effects of different combination of surgical techniques for recurrent patella dislocation (RPD) remain unclear. Thus, aim of this study was to investigate the surgical outcomes of different combination of surgical techniques for RPD. METHODS: The clinical data of 79 patients with RPD from August 2014 to October 2016 were analysed retrospectively. Knee joint was assessed according to measurements of the congruence angle (CA), patellar tilt angle (PTA) and lateral patellofemoral angle (LPFA). Knee function was evaluated by Kujala patellofemoral score, Lysholm knee score and Tegner score. Patients were followed up by out-patient examination and telephone till October 2018. RESULTS: Preoperative clinical characteristics were similar across groups. It was statistically insignificant among three groups in CA, PTA, LPFA and redislocation rate. In term of knee functions, the MPFL reconstruction and LPR release group had the highest score (Lysholm score: 91.82 ± 4.64, Kujala score: 94.22 ± 4.26, Tegner score: 5.80 ± 1.00, respectively) and the LPR release and MPR plication had the lowest score (Lysholm score: 78.10 ± 6.90, Kujala score: 80.91 ± 4.30, Tegner score: 4.98 ± 1.22, respectively). CONCLUSION: Three combinations of surgical methods were similar in terms of postoperative joint congruence and redislocation rate, but MPFL reconstruction combined with LPR release is worthy to be promoted with the highest knee function scores.

10.
Biomater Sci ; 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32100739

RESUMO

The efficiency of drug delivery and bioavailability to tumor cells are crucial for effective cancer chemotherapy. Herein, a doxorubicin (DOX) encapsulated lysolipid-based thermosensitive liposome decorated with cRGD peptide (RTSL) is conjugated on the surface of an IR780-loaded microbubble (IMB) to synthesize RTSL-IMBs. Sequentially taking advantage of acoustic-assisted early extravasation and thermo-triggered interstitium ultrafast drug release, RTSL-IMBs combine with ultrasound (US) and laser irradiation can advance drug delivery and bioavailability. In vitro experiments demonstrate that RTSL-IMBs associated with a two-step protocol (subsequently US irradiation for 1 min and laser irradiation for 5 min) can dramatically enhance the cellular uptake and bioavailability of DOX. In vivo fluorescence imaging studies reveal that the combination of RTSL-IMBs and US shows a 2.8-fold intratumoral drug accumulation increase at 0.5 h post-injection, while it will take 48 h to reach the same level of intratumoral drug accumulation for the RTSL-IMB group alone. Interestingly, the following localized application of a laser can further increase drug accumulation and slow tumor clearance. Histological analysis demonstrates that the combinational RTSL-IMBs, US and laser significantly improve the drug penetration distance and delivery efficiency in the tumor core. In this study, the acoustic/thermo-responsive hybrid system shows potential for advancing DOX chemotherapy in breast cancer cell MCF-7 xenograft nude mice.

11.
Sci Rep ; 10(1): 3573, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107429

RESUMO

Sandy sediments cover 50-60% of the continental shelves and are highly efficient bioreactors in which organic carbon is remineralized and inorganic nitrogen is reduced to N2. As such they seem to play an important role, buffering the open ocean from anthropogenic nitrogen inputs and likely remineralizing the vast amounts of organic matter formed in the highly productive surface waters. To date however, little is known about the interrelation between porewater transport, grain properties and microbial colonization and the consequences for remineralization rates in sandy sediments. To constrain the effect of theses factors on remineralization in silicate sands, we incubated North Sea sediments in flow-through reactors after separating into five different grain size fractions. Bulk sediment and sediment grain properties were measured along with microbial colonization and cell abundances, oxygen consumption and denitrification rates. Volumetric oxygen consumption ranged from 14 to 77 µmol O2 l-1 h-1 while nitrogen-loss via denitrification was between 3.7 and 8.4 µmol N l-1 h-1. Oxygen consumption and denitrification rates were linearly correlated to the microbial cell abundances, which ranged from 2.9 to 5.4·108 cells cm-3. We found, that cell abundance and consumption rates in sandy sediments are influenced (i) by the surface area available for microbial colonization and (ii) by the exposure of these surfaces to the solute-supplying porewater flow. While protective structures such as cracks and depressions promote microbial colonization, the oxygen demand is only met by good ventilation of these structures, which is supported by a high sphericity of the grains. Based on our results, spherical sand grains with small depressions, i.e. golf ball like structures, provide the optimal supporting mineral structure for microorganisms on continental shelves.

12.
Oncogene ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32108166

RESUMO

Tumor invasion underlies further metastasis, the leading cause for cancer-related deaths. Deregulation of microRNAs has been identified associated with the malignant behavior of various cancers, including lung adenocarcinoma (LUAD), the major subtype of lung cancer. Here, we showed the significantly positive correlation between miR-629-5p level and tumor invasion in LUAD specimens (n = 49). In a human LUAD metastasis mouse model, H1650 cells (high level of miR-629-5p) were more aggressive than A549 cells (low level of miR-629-5p) in vivo, including higher incidence of vascular invasion and pulmonary colonization. Ectopic expression of miR-629-5p in A549 cells also increased their invasive capability. Then we identified that miR-629-5p promotes LUAD invasion in a mode of dual regulation via tumor cells invasion and endothelial cells permeability, respectively. In tumor cells, miR-629-5p enhanced motility and invasiveness of tumor cells by directly targeting PPWD1 (a cyclophilin), which clinically related to tumor invasion in LUAD specimens. Restoring PPWD1 protein significantly attenuated the invasion-promoting effects of miR-629-5p. Besides, exosomal-miR-629-5p secreted from tumor cells could be transferred to endothelial cells and increased endothelial monolayers permeability by suppressing CELSR1 (a nonclassic-type cadherin), which had a low level in the endothelial cells of invasive LUAD specimens. Activating the expression of CELSR1 in endothelial cells markedly blocked the effect of miR-629-5p. Our study suggests the dual roles of miR-629-5p in tumor cells and endothelial cells for LUAD invasion, implying a therapeutic option to targeting miR-629-5p using the "one stone, two birds" strategy in LUAD.

13.
Biol Sex Differ ; 11(1): 5, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959230

RESUMO

BACKGROUND: Accumulating evidence indicates that high-fat diet (HFD)-induced metabolic disorders are associated with dysbiosis of the gut microbiota. However, the sex-specific characteristics of the gut microbiota and its association with a sexually dimorphic response to a HFD remain unclear. METHODS: Male and female mice were randomly assigned to receive a chow diet (CD) or HFD for 12 weeks. A group of HFD mice were pretreated with antibiotic cocktails for 4 weeks. Body weight, insulin sensitivity and the levels of serum metabolic parameters (blood glucose and insulin) were evaluated. 16S rRNA gene sequencing was performed to analyze the composition of the gut microbiota. RESULTS: HFD-induced body weight gain (BWG) was higher in male mice than in female mice. While insulin resistance was increased in the HFD group compared to CD group in male mice, there was no difference in insulin resistance among female mice. Antibiotic-pretreatment alleviated HFD-induced insulin resistance in male mice and elevated fasting blood glucose in female mice. The composition of the gut microbiota in male mice was remarkably different from that in female mice independent of diet. A higher abundance of the genera Parabacteroides, Lactobacillus, Bacteroides, and Bifidobacterium was observed in females than inmales. HFD feeding also influenced the structure of the gut microbiota, as it decreased the abundance of short-chain fatty acids-producing bacteria including Roseburia and Lachnospiraceae_NK4A136_group. Alterations in the gut microbiota in response to antibiotics followed by HFD were different between males and females, indicating sex-dependent sensitivity to antibiotics. CONCLUSIONS: We identified that sex had a greater impact on the composition of gut microbiota than environmental factors (HFD and antibiotics). The enrichment of beneficial microbes in female mice may be associated with the resistance of female mice to HFD-induced metabolic disorders, which was weakened by antibiotic pretreatment.

14.
ACS Appl Mater Interfaces ; 12(5): 5520-5530, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31891473

RESUMO

Radiotherapy (RT) is one of the most widely used cancer treatments in the clinical setting, while hypoxia-associated resistance often occurs. Herein, a PEGylated TaOx-based oxygen-carrying nanoplatform was constructed for triple sensitizing tumor radiotherapy. The high-Z element based hollow mesoporous TaOx nanospheres were prepared following the in situ growth of ultrasmall CuS nanocrystals and then packaged with O2-saturated perfluoropentane (PFP). NIR laser-triggered mild hyperthermia would lead to the increase of intratumoral blood flow, together with the release of O2, the radiotherapeutic efficiency would be enhanced. Alternatively, radiant energy would be deposited inside the tumor by the Ta element, therefore triple sensitization of radiotherapy could be achieved. The in vivo studies showed that the as-prepared nanospheres could achieve almost total inhibition of tumor growth without obvious side effects, which provides new possibilities for multisensitizing tumor radiotherapy.

15.
Artigo em Inglês | MEDLINE | ID: mdl-31923124

RESUMO

STUDY DESIGN: A prospective cohort study. OBJECTIVE: We conducted a prospective cohort study to identify the association between steroids and clinical worsening and compare outcomes between patients with and without preoperative steroid administration. SUMMARY OF BACKGROUND DATA: Patients with SDAVFs often were misdiagnosed and treated with steroids which led to acute worsening. METHODS: Patients with angiographically-confirmed SDAVFs were recruited consecutively between March 2013 and December 2014 in two referral centers. We reviewed the history of all the patients to identify those patients who were treated with steroids prior to exclusion of the fistulas. Modified Aminoff & Logue's scale (mALS) was used to evaluate the spinal cord function at different time points: before and after steroid administration, before operation and at 1-year follow-up. Paired t tests were used to assess the mALS of patients with steroid administration at different time points. Unpaired t tests and Pearson chi-square test were used to assess differences between patients with and without steroid administration. RESULTS: 18 patients with (18.2%) and 81 patients without (81.8%) steroid administration were included in this study. At baseline, there were no difference between both patient groups, in regards to age, gender, duration, location of fistula, treatment and preoperative mALS. However, patients without steroid administration had statistically significant better outcome according to their mALS at 1-year follow-up (P < 0.05). CONCLUSION: Steroid administration can induce acute clinical worsening in patients with SDAVFs that may persist despite successful obliteration of the fistula and should thus be avoided. LEVEL OF EVIDENCE: 3.

16.
Nanoscale ; 12(3): 2022-2027, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31912851

RESUMO

Two-dimensional (2D) Mn-Fe layered double hydroxide (LDH) nanosheets are firstly examined to mediate an O-phenylenediamine (OPD) based fluorescent switch in the presence of ascorbic acid (AA). On one hand, Mn-Fe LDH mimicked the functions of oxidase to catalyze the oxidation of OPD to OPDox, emitting fluorescence at 565 nm. On the other hand, Mn-Fe LDH acts as a superior catalyst for the reaction between AA and OPD to generate 3-(1,2-dihydroxyethyl)furo[3,4-b]quinoxalin-1(3H)-one (N-heterocyclic compound) with an emergence of the maximum emission at 425 nm (ca. 6 fold). The presence of AA not only induces the enhanced emission at 425 nm from the N-heterocyclic compound, but also leads to decreased fluorescence at 565 nm due to the decomposition of Mn-Fe LDH nanosheets. On the basis of the reversed fluorescence response at 425 and 565 nm, ratiometric fluorescence sensing methods (ΔF425 nm/ΔF565 nm) are developed for the determination of AA. With the assistance of alkaline phosphatase (ALP), the activity of ALP can be monitored using the ratiometric platform based on the hydrolyzing ascorbic acid 2-phosphate to yield AA with the detection limit of 0.16 mU mL-1. Different from the traditional ratiometric sensing platform, where two fluorescent probes are often introduced, the present ratiometric system derived from one signal precursor holds great potential in developing a facile platform and broadens the application of 2D nanomaterials in the field of biology.

17.
Mar Pollut Bull ; 152: 110907, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31957682

RESUMO

Marine microorganisms play an irreplaceable role in removing spilled oil. Zhoushan archipelago has one of the busiest ports and oil stockpiles in China. However, little is known about which and how fast oil-degrading microorganisms could biodegrade spilled oil here. By combining 14C-/3H-based radiotracer assays and MiSeq sequencing, we report the successive pattern of microbial oil-degrading activities and community compositions. The biodegradation rates of alkanes and PAHs (Polycyclic Aromatic Hydrocarbons) were significantly stimulated by oil addition, and reached their maximum after incubation for 3 and 7 days, respectively. Meanwhile, the abundances of alkB and phnAc genes increased and the bacterial communities continuously shifted. Potential oil-degrading bacteria Alcanivorax, Erythrobacter were the dominant degraders by day 3, whereas the dominant degraders shifted to C1-B045, Alteromonas, Pseudohongiella in the later period. These results provide valuable insights into the cooperative system of the versatile oil-degrading bacteria in successively biodegrading complex oil hydrocarbons in oil spills.

18.
Neuron ; 105(5): 822-836.e7, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-31899072

RESUMO

Mutations in the GBA1 gene are the most common genetic risk factor for Parkinson's disease (PD) and dementia with Lewy bodies (DLB). GBA1 encodes the lysosomal lipid hydrolase glucocerebrosidase (GCase), and its activity has been linked to accumulation of α-synuclein. The current study systematically examines the relationship between GCase activity and both pathogenic and non-pathogenic forms of α-synuclein in primary hippocampal, cortical, and midbrain neuron and astrocyte cultures, as well as in transgenic mice and a non-transgenic mouse model of PD. We find that reduced GCase activity does not result in aggregation of α-synuclein. However, in the context of extant misfolded α-synuclein, GCase activity modulates neuronal susceptibility to pathology. Furthermore, this modulation does not depend on neuron type but rather is driven by the level of pathological α-synuclein seeds. This study has implications for understanding how GBA1 mutations influence PD pathogenesis and provides a platform for testing novel therapeutics.

19.
Int J Biol Macromol ; 146: 80-88, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31891700

RESUMO

A gene encoding a halohydrin dehalogenase from Pseudomonas pohangensis (PpHHDH) was identified, synthesized and expressed in Escherichia coli. Subsequently, we used protein engineering to enhance the enzyme's enantioselectivity. We created two enantiocomplementary HHDH mutants, N160L and Q159L, which exhibited higher S- and R-selectivity toward PGE, respectively. The exchange of Leu at 159 for Gln led to a 2.3-fold increase in enantioselectivity (E-value of 22.2) compared to the wild-type. In addition, the N160L mutant displayed an inverted enantioselectivity (from ER = 9.8 to ES = 21.6) toward PGE. The wild-type PpHHDH and its variants were purified and characterized. They all displayed maximum activity at pH 7.5. The optimum temperature of mutant Q159L and N160L was increased from 35 °C to 40 °C. The wild-type PpHHDH and N160L mutant had good pH stability at pH 5.0-7.5, and Q159L showed an even wider range of pH tolerance, from pH 4.5 to pH 8.0. The mutants N160L and Q159L showed slightly better thermostability than wild-type PpHHDH. For most tested substrates, the two variants showed higher enantioselectivity. These findings further confirmed the importance of amino acid residues at positions 159 and 160 for the enantioselectivity of PpHHDH.

20.
J Chromatogr A ; 1609: 460510, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31515077

RESUMO

In this study, a novel phenyl-boronic acid polymeric monolith (PBAPM) in polyether ether ketone (PEEK) tube was fabricated. The inner wall of PEEK tube was modified with mussel inspired polydopamine layer to firmly bond PBAPM, so as to avoid the outflow of PBAPM from PEEK tube and improve the service life and application scope of PBAPM. The PBAPM was synthesized by initiator-free ring-opening polymerization based on our previous work. The boric acid groups provided B-N coordination sites, as well as the hydrophobic amino and epoxy monomers provided hydrophobic interaction sites. Due to the synergistic effect of hydrophobic interaction and B-N coordination, the PBAPM exhibited excellent binding amounts for nitrogen-containing sulfonamides (SAs). In addition, the PBAPM possessed excellent stability, rigidity and permeability. Therefore, the PBAPM was used as solid phase microextraction (SPME) material for enrichment and separation of SAs from aqueous samples. The PBAPM SPME was optimized in detail, and combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis for simultaneous determination of 10 kinds of SAs from tap, lake and river water. Using only 1 mL of water samples, limit of quantitation of SAs could reach 0.54-4.5 ng L-1. Recoveries of standard spiked SAs from water samples were between 82.0% and 105.4%, with intra-day and inter-day relative standard deviation ranging from 3.3% to 5.6% and 4.2% to 8.1%, respectively. The PBAPM SPME combined with UPLC-MS/MS method shown better or similar recoveries, and used fewer samples than previous methods. These results demonstrated that the PBAPM could selectively separate and enrich ultra-trace nitrogen-containing SAs from aqueous samples.


Assuntos
Ácidos Borônicos/química , Cromatografia Líquida de Alta Pressão/métodos , Polimerização , Polímeros/química , Microextração em Fase Sólida , Sulfonamidas/análise , Espectrometria de Massas em Tandem/métodos , Sulfonamidas/química , Água/química , Poluentes Químicos da Água/análise
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