Dopamine receptors, including D1- and D2-like receptors, are important therapeutic targets in a variety of neurological syndromes, as well as cardiovascular and kidney diseases. Here, we present five ...cryoelectron microscopy (cryo-EM) structures of the dopamine D1 receptor (DRD1) coupled to Gs heterotrimer in complex with three catechol-based agonists, a non-catechol agonist, and a positive allosteric modulator for endogenous dopamine. These structures revealed that a polar interaction network is essential for catecholamine-like agonist recognition, whereas specific motifs in the extended binding pocket were responsible for discriminating D1- from D2-like receptors. Moreover, allosteric binding at a distinct inner surface pocket improved the activity of DRD1 by stabilizing endogenous dopamine interaction at the orthosteric site. DRD1-Gs interface revealed key features that serve as determinants for G protein coupling. Together, our study provides a structural understanding of the ligand recognition, allosteric regulation, and G protein coupling mechanisms of DRD1.
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•Structures of DRD1-Gs in complex with catechol-based and non-catechol agonists•Key polar interaction network is involved in DRD1 activation•Specific features for agonists interaction and Gs coupling of DRD1 are determined•Structure of DRD1-Gs complexed with dopamine and positive allosteric modulator•Structural basis of allosteric regulation of DRD1 by LY3154207 is investigated
The cryo-EM structures of DRD1 coupled to its G protein, in complex with important agonists, elucidates the mechanism of G-protein-coupled selectivity and will facilitate future drug discovery and design.
Tumor-derived exosomes and their contents promote cancer metastasis. Phosphoglycerate mutase 1 (PGAM1) is involved in various cancer-related processes. Nevertheless, the underlying mechanism of ...exosomal PGAM1 in prostate cancer (PCa) metastasis remains unclear. In this study, we performed in vitro and in vivo to determine the functions of exosomal PGAM1 in the angiogenesis of patients with metastatic PCa. We performed Glutathione-S-transferase pulldown, co-immunoprecipitation, western blotting and gelatin degradation assays to determine the pathway mediating the effect of exosomal PGAM1 in PCa. Our results revealed a significant increase in exosomal PGAM1 levels in the plasma of patients with metastatic PCa compared to patients with non-metastatic PCa. Furthermore, PGAM1 was a key factor initiating PCa cell metastasis by promoting invadopodia formation and could be conveyed by exosomes from PCa cells to human umbilical vein endothelial cells (HUVECs). In addition, exosomal PGAM1 could bind to γ-actin (ACTG1), which promotes podosome formation and neovascular sprouting in HUVECs. In vivo results revealed exosomal PGAM1 enhanced lung metastasis in nude mice injected with PCa cells via the tail vein. In summary, exosomal PGAM1 promotes angiogenesis and could be used as a liquid biopsy marker for PCa metastasis.
The extracellular cold-active protease from the psychrophilic bacterium
Pseudoalteromonas sp. NJ276 was purified by 22.5-fold using precipitate of saturation (NH
4)
2SO
4, DEAE-Sephadex A50 and ...Sephadex G-75. It was shown that purified enzyme was homogeneous in terms of SDS-PAGE with molecular mass estimate of 28
kDa. The protease depicted an optimal pH of 8.0 and was stable at pH 7.0–9.0, and its optimal temperature was at 30
°C. The protease was completely inhibited by PSFM. It was partially inhibited by metal salts, especially, had high tolerance to a wide range of NaCl concentrations (0–3
M NaCl). The highest
k
cat and
k
cat/
K
m values were observed at 35
°C, and 35 and 54% of their highest values retained at 0
°C, respectively. Milk protein treated by this protease released more free amino acids than those treated by mesophilic papain at 4
°C. These results suggested that
Pseudoalteromonas sp. NJ276 protease had broad substrate specificities and potential application in low-temperature food processing.
The 3D-printed Ti-6Al-4V intervertebral fusion cage is fabricated to be biocompatible with improved stiffness, fatigue life, and osteogenic differentiation, which are greatly enhanced by heat ...treatment and surface modification. The flexible cage’s life, which exceeds the standard dynamic fatigue requirement of 5 × 106 cycles based on the ASTM F2077 and F2267 test methods, is achieved by heat treatment at 800 ℃ in argon atmosphere, shot peening, and adjusting the α to β phase ratio to increase mechanical toughness. Surface modification via sandblasting and chemical etching removes the surface oxide layer and forms submicron pores on the surface of the cage, which significantly boosts cell proliferation, differentiation, and osteoblast mineralization. This work exhibits a novel design of Ti-6Al-4V intervertebral fusion cage with biocompatible stiffness, enhanced fatigue life, and improved osteogenic differentiation achieved by reducing residual stress, modifying surface micro-pores, and optimizing microstructure.
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•Ti-6Al-4V intervertebral cage with biocompatible stiffness, enhanced fatigue life, and improved osteogenic differentiation.•Heat treatment and shot peening to adjust residual stress and optimizing microstructure to increase mechanical toughness.•Sandblasting and chemical etching boost cell proliferation, differentiation, and osteoblast mineralization.
Colwellia sp. NJ341, isolated from Antarctic sea ice, secreted a cold-active serine protease. The purified protease had an apparent Mr of 60 kDa by SDS-PAGE and MALDI-TOF MS. It was active from pH ...5–12 with maximum activity at 35 °C (assayed over 10 min). Activity at 0 °C was nearly 30% of the maximum activity. It was completely inhibited by phenylmethylsulfonyl fluoride.
The effect of ultraviolet-B (UV-B) radiation on Antarctic phytoplankton has become an attractive ecological issue as a result of annual springtime ozone depletion. The effects of UV-B radiation on ...the growth and antioxidant enzymes were investigated using Antarctic sea ice microalgae Chlamydomonas sp. ICE-L as the material in this study. The results demonstrated that UV-B radiation could notably inhibit the growth, especially at high UV-B radiation intensity (70 μW cm⁻²). Malondialdehyde and O₂ ·⁻ content in ICE-L increased rapidly in early days (1-3 days) exposed to UV-B radiation enhancement, then decreased rapidly. In the stress of UV-B radiation enhancement, the superoxide dismutase, peroxidase and Catalase activities of 1-4 days in ICE-L were obviously higher than those in the control, and their activities became higher at high UV-B radiation intensity (70 μW cm⁻²). These enzymes activity of 7 days would kept stable at low UV-B radiation intensity (35 μW cm⁻²), but kept high level at high UV-B radiation intensity (70 μW cm⁻²). However, the ascorbate peroxidase activity in ICE-L kept stable under the stress of UV-B radiation enhancement. The above experimental results indicated that the antioxidant enzyme system played an important role in the adaptation of Antarctic ice microalgae under the UV-B radiation change of Antarctic ecosystems.
Background There are no data on more tolerable capecitabine doses in elderly patients in Chinese population. The aim of this study was to evaluate the activity and safety of capecitabine combined ...with weekly docetaxel for the treatment of anthracycline-resistant metastatic breast cancer （MBC） in older Chinese patients. Methods MBC patients aged 〉65 years pretreated with 1-5 prior chemotherapy regimens, including an anthracycline, received oral capecitabine 825 mg/m^2 twice daily, days 1-14, plus docetaxel 30 mg/m^2 on days 1 and 8 every 21 days. All 41 enrolled patients received at least 1 dose of treatment and were evaluable for safety; 38 received at least 2 cycles （median 4, range 2-8） and were evaluable for efficacy. Results The overall objective response rate was 47%, including complete responses in 8% of patients. Median time to progression was 8.9 months. Median overall survival was 17.6 months. The most common side effects were haematological and gastrointestinal toxicities and hand-foot syndrome. The only grade 3/4 adverse events were neutropenia （12%）, alopecia （7%）, grade 3 nausea and vomiting （2%） and grade 3 nail toxicity （2%）. Conclusions Capecitabine 825 mg/m^2 twice daily plus weekly docetaxel is active with an acceptable safety profile in Chinese women 〉65 years with anthracycline-resistant MBC. Efficacy and tolerability compare favourably with previously reported trials evaluating higher capecitabine doses in combination with 3-weekly or weekly docetaxel.
In the early 1970s, the Chinese Equine Infectious Anemia Virus (EIAV) vaccine, EIAV
DLA, was developed through successive passages of a wild-type virulent virus (EIAV
L) in donkeys
in vivo and then ...in donkey macrophages
in vitro. EIAV attenuation and cell tropism adaptation are associated with changes in both envelope and long terminal repeat (LTR). However, specific LTR changes during Chinese EIAV attenuation have not been demonstrated. In this study, we compared LTR sequences from both virulent and attenuated EIAV strains and documented the diversities of LTR sequence from
in vivo and
in vitro infections. We found that EIAV LTRs of virulent strains were homologous, while EIAV vaccine have variable LTRs. Interestingly, experimental inoculation of EIAV
DLA into a horse resulted in a restriction of the LTR variation. Furthermore, LTRs from EIAV
DLA showed higher Tat transactivated activity than LTRs from virulent strains. By using chimeric clones of wild-type LTR and vaccine LTR, the main difference of activity was mapped to the changes of R region, rather than U3 region.
To evaluate the effect of ilaprazole enteric tablets on intragastric pH in duodenal ulcer patients.
A randomized, double blind, positive controlled clinical trial was carried out. A total of ...forty-two patients with duodenal ulcer were randomized into low dose ilaprazole group (5 mg/d), medium dose ilaprazole group (10 mg/d), high dose ilaprazole group (20 mg/d) and omeprazole group (20 mg/d). An ambulatory 24 hour intragastric pH study was performed at the fifth treatment day. Fraction time pH above 3, 4 or 5, median values of 24 hour diurnal pH and 12 hour nocturnal pH, the percentage of patients with total time pH above 3, 4 or 5 at least for 18 hours were evaluated.
There were no significant differences of fraction time pH above 3 or 4, median values of 24 hour diurnal pH and 12 hour nocturnal pH and the percentage of patients with total time pH above 3, 4 or 5 at least for 18 hours among all the groups with different doses of ilaprazole and the omeprazole group. The fraction time pH above 5 in medium and
A psychrotrophic bacterium Colwellia sp. NJ341 from Antarctic sea ice could grow at -5 and 22 °C, and the extent of cellular protein content and growth were greater at low temperatures (0-10 °C) than ...at higher temperatures. SDS-PAGE analysis demonstrated the presence of a 7 kDa cold-shock protein. The further result of two-dimensional electrophoresis (2-DE) showed that two proteins a and c were newly synthesized at near-freezing temperatures. With matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) analysis, proteins a and c were identified as glutathione S-transferase (GST) and cold-shock protein A (CspA), respectively, which were involved in cold-adaptation at near-freezing temperature in an Antarctic psychrophilic bacterium Colwellia sp. NJ341.
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