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1.
Methods Mol Biol ; 2186: 213-225, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32918740

RESUMO

Reconstituted model membrane systems are powerful platforms to tackle interesting problems existing in membrane biology. One of the barriers to efficient drug delivery, as therapeutics to disease, is the physical membrane barrier of the cell. Small molecule can typically diffuse through the membrane; however, biomolecules such as proteins or nucleic acids cannot passively diffuse the bilayer and thus much research has been geared to engineering protein and/or nucleic acids delivery methods. One delivery method uses cell penetrating peptides (CPPs). In this chapter, we introduce the model "membrane army" arranged in dimple chip to study the delivery of ß-galactosidase by a CPP known as Pep-1. This method uses droplet interface bilayer technology (DIB). It accelerates the speed to screen through the working conditions in CPP-assisted protein translocations because each chip provides dimples that can accommodate 36 pairs of droplets or 18 model bilayers. We will use one of the successful translocation conditions of ß-galactosidase delivery as the example to illustrate how the model "membrane army" is built and utilized.

2.
Meat Sci ; 171: 108269, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32768894

RESUMO

The study explored the preservative effects of adding different levels of cinnamon bark oil on meat quality of ground lamb. The longissimus thoracis et lumborum (LTL) meat samples were treated with 0 (control), 0.01%, 0.025%, 0.05%, and 0.5% of cinnamon bark oil and stored at 4 °C for 16 days. Microbial populations of TVC, lactic acid bacteria, and Enterobacteriaceae were reduced up to 0.6 to 1.9 log CFU/g than control from day 4 to 16 during storage. The samples adding 0.025% and 0.05% cinnamon bark oil showed lower thiobarbituric acid reactive substance (TBARS) and pH values but higher L⁎, a⁎, R630/580 and Chroma values than all the other samples (P < 0.05). The relative content of oxymyoglobin was higher for 0.01%, 0.025%, and 0.05% cinnamon bark oil samples after 12 days of storage than other treatments (P < 0.05). In conclusion, cinnamon bark oil of 0.025% and 0.05% had a better preservative effect on the lamb meat quality during storage.

3.
Clin Transl Sci ; 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33045134

RESUMO

Extranodal natural killer/T-cell lymphoma, nasal type (ENKL) is a rare peripheral T-cell lymphoma that predominantly occurs in Asian and South American populations. The treatment of ENKL has been a challenge for a long time. This study was conducted to compare the clinical efficacy and safety of cisplatin, dexamethasone, gemcitabine, and pegaspargase (DDGP) and methotrexate, dexamethasone, ifosfamide, L-asparaginase, and etoposide (SMILE) regimens for relapsed/refractory ENKL and explore the prognostic factors. From October 2014 to July 2019, 54 patients with relapsed/refractory ENKL who received DDGP or SMILE chemotherapy were retrospectively assessed in this study. Thirty-one patients received DDGP chemotherapy and 23 patients received SMILE chemotherapy. A higher complete response rate was observed in patients treated with DDGP regimen (61.3% vs. 30.4%, P = 0.025). The DDGP group (95% confidence interval (CI) of 5-year progression-free survival (PFS): 24.6-66.2%; 95% CI of 5-year overall survival (OS): 8.5-91.7%) was also significantly associated with longer 5-year PFS and 5-year OS (P = 0.008 for 5-year PFS, P = 0.023 for 5-year OS). More serious leucopenia (P = 0.021), neutropenia (P = 0.041), and allergy (P = 0.040) were observed in the SMILE group. Post-treatment Epstein-Barr virus (EBV)-DNA status (P = 0.001 for PFS, P = 0.018 for OS) was identified as a significant prognostic factor for PFS and OS in multivariate analysis. The present research suggested that compared with SMILE chemotherapy, DDGP chemotherapy can significantly improve the response and survival of relapsed/refractory ENKL with better tolerance. Post-treatment EBV-DNA status was identified as a significant prognostic factor for PFS and OS in relapsed/refractory ENKL.

4.
Immunopharmacol Immunotoxicol ; : 1-29, 2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33045867

RESUMO

Introduction: Vitiligo is the most common type of depigmented skin disease. Cellular oxidative stress caused by reactive oxygen species (ROS) has been implicated in the pathogenesis of vitiligo. Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway plays an important role in melanocytes against hydrogen peroxide (H2O2) induced oxidative stress. In addition, vitexin may protect vitiligo by inhibiting oxidative stress and inflammation.Objective: In the present study, we aimed to investigate the antioxidant effect of vitexin-activated mitogen-activated protein kinase (MAPK)-Nrf2/ARE axis in vitiligo.Methods: MTT assay identified cells viability of human melanocyte PIG1. Cell apoptosis was evaluated by flow cytometry. Gene and protein expression levels were analyzed by quantitative real time PCR (qPCR) and Western blotting. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expressions of inflammatory factors and ROS production.Results: Vitexin inhibited H2O2-induced melanocyte apoptosis and promoted cell proliferation. Moreover, vitexin decreased expression of interleukin-1ß (IL-1ß), IL-17A and ROS in melanocytes induced by H2O2. Subsequently, activation of MAPK-Nrf2/ARE signaling was readily induced by vitexin treatment, as evidenced by upregulation of antioxidant genes including heme oxygenase 1 (HO-1) and superoxide dismutase (SOD). Knockdown of Nrf2 reversed the protective effect of vitexin on H2O2-induced melanocytes. And, knockdown of Nrf2 increased the expression of IL-1ß, IL-17A and ROS, and reduced HO-1 and SOD expression.Conclusions: Vitexin protected melanocytes from oxidative stress by activating MAPK-Nrf2/ARE signaling pathway. Our results suggested that the role of Nrf2/ARE axis in antioxidant defense of melanocytes, and the potential therapeutic strategy for vitiligo.

5.
Artigo em Inglês | MEDLINE | ID: mdl-33025280

RESUMO

PURPOSE: Nasal type extranodal natural killer/T-cell lymphoma (ENKTL) can be associated with hemophagocytic lymphohistiocytosis (NK/T-LAHLH), which is a rare and fatal disease with no effective therapy. We evaluated whether etoposide + dexamethasone-based chemotherapy regimens might be useful for treating NK/T-LAHLH. METHODS: This retrospective single-center study evaluated clinical data from 37 patients with NK/T-LAHLH who were treated between May 2008 and January 2020. RESULTS: Among 363 patients with ENKTL, the cumulative incidence of HLH was 11.9%. Among 43 patients with NK/T-LAHLH, 37 patients received etoposide + dexamethasone-based chemotherapy regimens, with an overall response rate of 45.9% for the HLH. The overall response rate was substantially higher for newly diagnosed NK/T-LAHLH than it was for relapsed or refractory NK/T-LAHLH (66.7% vs. 18.8%). The median overall follow-up time was 4 months, with overall survival rates of 81.1% at 1 month, 62.2% at 2 months, 56.8% at 3 months, and 34.4% at 6 months. Significantly better overall survival (all P < 0.05) was observed for patients with newly diagnosed NK/T-LAHLH (vs. relapsed/refractory disease), stage I/II disease (vs. stage III/IV disease), and nasal disease (vs. non-nasal disease). Patients who responded to the ENKTL treatment also experienced response in their HLH; 8 patients experienced continued complete response for both HLH and ENKTL. Multivariate analysis revealed that a poor prognosis among patients with NK/T-LAHLH was independently related to relapsed/refractory ENKTL and non-nasal disease. CONCLUSION: Although patients with NK/T-LAHLH generally experienced poor outcomes, etoposide + dexamethasone-based chemotherapy regimens were associated with good outcomes among select patients with newly diagnosed or stage I/II NK/T-LAHLH.

6.
Plant Cell ; 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037144

RESUMO

The plant defense hormone salicylic acid (SA) is perceived by two classes of receptors, NPR1 and NPR3/NPR4. They function in two parallel pathways to regulate SA-induced defense gene expression. To better understand the roles of the SA receptors in plant defense, we systematically analyzed their contributions to different aspects of plant immunity using the SA-insensitive npr1-1 npr4-4D double mutant. We found that perception of SA by NPR1 and NPR4 is required for activation of N-hydroxypipecolic acid (NHP) biosynthesis, which is essential for inducing systemic acquired resistance (SAR). In addition, both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) are severely compromised in the npr1-1 npr4-4D double mutant. Interestingly, the PTI and ETI attenuation in npr1-1 npr4-4D is more dramatic compared to the SA-induction deficient 2-1 (sid2-1) mutant, suggesting that perception of residual levels of SA in sid2-1 also contributes to immunity. Furthermore, NPR1 and NPR4 are involved in positive feedback amplification of SA biosynthesis and regulation of SA homeostasis through modifications including 5-hydroxylation and glycosylation. Thus, the SA receptors NPR1 and NPR4 play broad roles in plant immunity.

7.
Cell Mol Biol (Noisy-le-grand) ; 66(6): 71-75, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33040788

RESUMO

In this study, we investigated the effect of latanoprost on the expression of TGF- ß1 and Wnt / ß - Catenin signal pathway in the choroid of form-deprivation myopia model rats. Forty rats were randomly divided into two groups: the control group and the FDM model group. Each group had 20 rats. The FDM model group was established by feeding latanoprost daily for 28 days. 15 rats in each group were used to measure the length of the ocular axis and the level of TGF-ß1 in choroidal tissue; the remaining 5 rats in each group were used for choroidal fibroblast culture. After modeling, the rats were killed, the length of the ocular axis was measured with a vernier caliper, and the level of TGF - ß1 protein and mRNA in the choroidal tissue of each group were measured with RT-PCR method. Results showed that compared with the control group, there was a significant difference in the axial length of the FDM model group (P< 0.05). There was a significant difference in the expression of TGF- ß1 protein and mRNA between the two groups (P<0.05). The cultured cells were identified as choroidal fibroblasts by immunocytochemistry. There was no significant difference (P>0.05) in the comparison of GSK3 ß protein in choroidal fibroblasts of rats in each group. TGF-ß 1 and APC protein in FDM group were significantly lower than those in the control group (P<0.05), while dcl3, p21-gsk3 ß and ß - Catenin proteins were significantly higher (P<0.05), and there was no significant difference (P>0.05) in the ratio of various indexes protein in FDM + ddk1 group and the comparison of TGF - ß1 and APC protein in FDM + ddk1 group and FDM group The expression of dcl3, p21-gsk3 ß and ß - Catenin decreased significantly (P<0.05). There was no significant difference in the expression of GSK3 ß mRNA in the choroidal fibroblasts of each group (P>0.05). The expression of TGF - ß 1 and APC mRNA in FDM group was significantly lower than that in the control group (P<0.05), while the expression of dcl3, p21-gsk3 ß and ß-catenin mRNA in FDM + ddk1 group was significantly higher than that in the control group (P<0.05) >In FDM + ddk1 group, TGF-ß 1 and APC mRNA were significantly lower than those in FDM group (P<0.05), while dcl3, p21-gsk3 ß and ß-Catenin mRNA were significantly higher (P<0.05).

8.
Artigo em Inglês | MEDLINE | ID: mdl-33048541

RESUMO

As the demand for batteries increases with the development of electric vehicles, the energy density of lithium-ion batteries (LIBs) should be continuously enhanced. Due to the excellent theoretical specific capacity, silicon (Si) is the most promising anode material for LIBs. Nevertheless, the application of Si-based anodes is constrained by critical problems such as low conductivity and extreme volume change. Herein, we demonstrate an effective strategy for the fabrication of a three-dimensional (3D) hierarchical porous-structured Si-based anode with dual MXene protection (namely, SiNP@MX1/MX2). By electrostatic force induced self-assembly between modified Si with a positive charge and MXene nanosheets with a negative charge on the surface, Si nanoparticles are riveted to the MXene nanosheets (namely, SiNP@MX1), and then embedded into the 3D MXene skeleton (MX2) via a hydrothermal reaction and freeze-drying. Through the tailored and reasonable design, the internal MX1 coating can accommodate the volume expansion and avoid particle aggregation. The external MX2 allows for rapid electron transport and ion transfer while further buffering volume changes. Most importantly, by preventing Si from directly contacting the electrolyte, the double MXene-wrapped protection design benefits from the formation of a stable solid electrolyte interphase (SEI) film. The SiNP@MX1/MX2 anode material has a high capacity of 1422 mA h g-1 at a current density of 0.5 A g-1 after 200 cycles, excellent cycle stability, and good rate performance. At the same time, the method proposed in this study is expected to be applied to the preparation of other alloy anodes/MXene hybrids for storage batteries.

9.
Carbohydr Polym ; 250: 116951, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33049893

RESUMO

A novel method for the quantitative characterization of incomplete degradation products of galactomannan (IDPG) was developed by ethanol fractional precipitation. In this work, IDPG in the enzymatic hydrolyzate of Sesbania cannabina galactomannan was fractionated into several fractions with high recovery (>96 %) by ethanol fractional precipitation. The average molecular weights of obtained fractions were in descending order with varied corresponding contents of galactomannan degradation products. Thus, the quantitative characterization of IDPG can be achieved. Moreover, the results of statistical validation and method robustness showed that the method has good reproducibility. Surprisingly, when this method was applied to the guar gum or locust bean gum enzymatic hydrolyzates, it was found that the lower the mannose to galactose ratio of un-hydrolyzed galactomannan, the higher the molecular weight of their degradation product obtained under same ethanol concentration. This method is effectively applied to the quantitative characterization of IDPG from other sources.

10.
Artigo em Inglês | MEDLINE | ID: mdl-33050690

RESUMO

Solar-driven water splitting is an appealing strategy to produce hydrogen energy. However, the non-negligible chance of reverse reactions due to a mixture of hydrogen molecules (H2) with oxygen species poses challenges for safe H2 collection and delivery, which hinders its applications. Using first-principles simulations, we propose a hybrid structure design where metal clusters of TM4 (TM = Au/Pt) are encapsulated in boron-carbon-nitride nanotube (BCNNT) decorated with CuN3 group. It can readily absorb ultraviolet-visible solar light to generate charge carriers. The energetic electrons and holes would be separately delivered to the reduction site of TM4 and the oxidation site of the BCNNT layer. Then, protons generated by water dissociation at the BCNNT layer will penetrate through BCNNT and consequently meet electrons at the TM4 site to be reduced into H2. As a selective sieve, BCNNT prevents oxygen species from going inside and H2 from crossing out so that H2 can be completely isolated. Further, the sufficient space of the tubular cavity endows the transportation feasibility of the produced H2 along the nanotube for collection. This proposed design combines photocatalytic hydrogen production and safe delivery, which may help in developing a practical solution for a photodriven hydrogen production.

11.
Artigo em Inglês | MEDLINE | ID: mdl-33051297

RESUMO

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global crisis. There is no therapeutic treatment specific for COVID-19. It is highly desirable to identify potential antiviral agents against SARS-CoV-2 from existing drugs available for other diseases and thus repurpose them for treatment of COVID-19. In general, a drug repurposing effort for treatment of a new disease, such as COVID-19, usually starts from a virtual screening of existing drugs, followed by experimental validation, but the actual hit rate is generally rather low with traditional computational methods. Here we report a virtual screening approach with accelerated free energy perturbation-based absolute binding free energy (FEP-ABFE) predictions and its use in identifying drugs targeting SARS-CoV-2 main protease (Mpro). The accurate FEP-ABFE predictions were based on the use of a restraint energy distribution (RED) function, making the practical FEP-ABFE-based virtual screening of the existing drug library possible. As a result, out of 25 drugs predicted, 15 were confirmed as potent inhibitors of SARS-CoV-2 Mpro The most potent one is dipyridamole (inhibitory constant Ki = 0.04 µM) which has shown promising therapeutic effects in subsequently conducted clinical studies for treatment of patients with COVID-19. Additionally, hydroxychloroquine (Ki = 0.36 µM) and chloroquine (Ki = 0.56 µM) were also found to potently inhibit SARS-CoV-2 Mpro We anticipate that the FEP-ABFE prediction-based virtual screening approach will be useful in many other drug repurposing or discovery efforts.

13.
J Cancer Res Ther ; 16(5): 1027-1037, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33004744

RESUMO

Purpose: We aimed to compare the outcomes of microwave ablation (MWA) alone with those of transarterial chemoembolization combined with MWA (TACE-MWA) for Barcelona clinic liver cancer (BCLC) Stage B hepatocellular carcinoma (HCC) and to identify the prognostic factors associated with the two treatments. Materials and Methods: This retrospective study was conducted in 150 BCLC Stage B HCC patients from April 2006 to November 2017. Of these, 88 patients were treated with MWA alone while 62 with TACE-MWA. Propensity score matching (PSM) was conducted to adjust for imbalances in clinical parameters. Procedure-related complications, local tumor progression (LTP), recurrence-free survival (RFS), and overall survival (OS) were analyzed. Results: Before PSM, the maximal tumor diameters were 6.0 ± 1.0 cm and 6.7 ± 1.3 cm in the TACE-MWA and MWA groups, respectively, with a significant difference (P = 0.002); a significant difference was also detected in α-fetoprotein level (P = 0.013). After PSM, no difference was found in the two parameters (P = 0.067, 0.470). Before and after PSM, no difference was detected in the procedure-related complications (P = 0.803 vs. 1.000, P = 1.000 vs. 1.000), RFS (P = 0.786 vs. 0.689), and OS (P = 0.684 vs. 0.929). Tumor size and α-fetoprotein level were independent influencing factors for OS before and after PSM (P = 0.009, 0.023), while tumor size (D > 7) was an independent risk factor for poor OS (P = 0.011). Tumor number was an independent risk factor for RFS before and after PSM (P = 0.007 vs. P = 0.008). A significant difference was detected in LTP between the two groups with single tumor before and after PSM (P = 0.059 vs. P = 0.006). Conclusions: The MWA alone group had RFS and OS comparable to that of the TACE-MWA group. TACE-MWA was effective in controlling LTP in patients with a single tumor.

14.
Curr Microbiol ; 2020 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-33011835

RESUMO

Many organisms secrete xylanase, an import group of proteins hydrolyzing xylan, and thus are able to use xylan as their carbon source. In this study, we sequenced the whole genome of a bacterial strain, YD01, which was isolated from the sludge near the sewage discharge outlet of a papermill and showed high alkalic xylanase activity. Its genome consists of a chromosome and two plasmids. Six rRNA genes, 46 tRNA genes, 3136 CDSs as well as 955 repetitive sequences were predicted. 3046 CDSs were functionally annotated. Phylogenetic analysis on 16S rRNA shows that YD01 is a new species in Microbacterium genus and is taxonomically close to M. jejuense THG-C31T and M. kyungheense THG-C26T. A comparative study on phylogenetic trees of 16S rRNA and xylanase genes suggests that xylanase genes in YD01 may originate from horizontal gene transfer instead of ancestral gene duplication.

15.
Artigo em Inglês | MEDLINE | ID: mdl-33015742

RESUMO

An integrated process to increase the yield of incomplete degradation products of galactomannan (GalM) especially for galactomanno-oligosaccharides (GalMOS) was suggested. Trichoderma reesei employed Avicel or GalMOS as a carbon source to produce ß-mannanase or α-galactosidase independently, with a result of 3.78 ± 0.12 U/mL of ß-mannanase activity and 2.45 ± 0.06 U/mL of α-galactosidase activity which were obtained, respectively. GalM in Sesbania seed was hydrolyzed simultaneously by a mixture of crude enzyme with ß-mannanase and α-galactosidase at a dosage of 20 U/g GalM and 15 U/g GalM, respectively; the yields of incomplete degradation products of GalM (IDP-GalM) and GalMOS were 78.84% ± 3.14% and 30.94% ± 0.38%, respectively, which was beneficial to improve the biological activity of the incomplete degradation products. The role of α-galactosidase addition in mixture enzymes is to remove the galactose substituents from mannan backbone of GalM and alleviate the steric hindrance of ß-mannanase hydrolysis.

16.
Micromachines (Basel) ; 11(10)2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33008034

RESUMO

Piezoelectric transducer wafers are usually used in pairs to adjust the resonant cavity length of the ring laser gyro. In practice, the paired wafers are required to have similar piezoelectric charge coefficient d31. To handle the pairing operation in-batch, an automatic sorting system was developed on the basis of deformation measurement, which adopted a frame of a Cartesian-coordinate robot. The wafers were self-aligned in the vertical direction, and a vacuum holder was used to pick up, transfer, and then place them on thee testing desk one by one. The excitation voltage was loaded on the wafer by a specifically designed electrode, and the resulting micro deformation was measured by dual opposite inductive micrometers using the relative measurement principle. This particular electrode has the function of attitude self-adjustment and vacuum adsorption, which is conducive to loading the voltage reliably and protecting the wafer from undesired damage. Finally, the wafers were transported to different stock bins based on the measuring results. This system is suited to handle a mass of wafers by continuous processing on site for its high reliability and measurement consistency. The measurement accuracy, validated by laser interferometry, was better than 0.5 µm and the repeatability was superior to 0.1 µm.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33030889

RESUMO

Diffusion-driven layer-by-layer (dd-LbL) assembly is a simple yet versatile process that can be used to construct graphene oxide (GO) into a three-dimensional (3D) porous framework with good mechanical stability. In particular, the oxygen functional groups on the GO surface are well retained, providing nucleation sites for further chemical reactions to be performed upon. Therefore, such a scaffold should serve as a promising starting material for creating a wide range of 3D graphene-based composites while maintaining a high accessible surface area. Herein, we demonstrate the use of the porous GO macrostructure derived from dd-LbL assembly for the preparation of graphene-MnCO3 hybrid structures. MnCO3 is a newly reported pseudocapacitive material for supercapacitors; however, its electrochemical performance is hampered by its low electrical conductivity and poor chemical stability. Through reaction between KMnO4 and GO during a hydrothermal process, the surface of the porous scaffold was rendered with uniform MnCO3 nanoparticles. With the reduced graphene oxide (rGO) sheets serving as the conductive backbone, the resultant MnCO3 nanoparticles exhibited a capacitance of 698 F g-1 at a charge/discharge current of 0.5 mA (320 F g-1 for the combined rGO and MnCO3 composite). Furthermore, the electrode maintained 77% of its initial capacity even after 5000 cycles of charge/discharge tests at 20 mA.

18.
Artigo em Inglês | MEDLINE | ID: mdl-33001801

RESUMO

This paper presents a new framework, Knowledge-Transfer Generative Adversarial Network (KT-GAN), for fine-grained text-to-image generation. We introduce two novel mechanisms: an Alternate Attention-Transfer Mechanism (AATM) and a Semantic Distillation Mechanism (SDM), to help generator better bridge the cross-domain gap between text and image. The AATM updates word attention weights and attention weights of image sub-regions alternately, to progressively highlight important word information and enrich details of synthesized images. The SDM uses the image encoder trained in the Image-to-Image task to guide training of the text encoder in the Text-to-Image task, for generating better text features and higher-quality images. With extensive experimental validation on two public datasets, our KT-GAN outperforms the baseline method significantly, and also achieves the competive results over different evaluation metrics.

19.
Microb Cell Fact ; 19(1): 187, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33008397

RESUMO

Mycobacterium neoaurum strains can transform phytosterols to 4-androstene-3,17-dione (4-AD), a key intermediate for the synthesis of advanced steroidal medicines. In this work, we presented the complete genome sequence of the M. neoaurum strain HGMS2, which transforms ß-sitosterol to 4-AD. Through genome annotation, a phytosterol-degrading pathway in HGMS2 was predicted and further shown to form a 9,10-secosteroid intermediate by five groups of enzymes. These five groups of enzymes included three cholesterol oxidases (ChoM; group 1: ChoM1, ChoM2 and Hsd), two monooxygenases (Mon; group 2: Mon164 and Mon197), a set of enzymes for side-chain degradation (group 3), one 3-ketosteroid-1,2-dehydrogenase (KstD; group 4: KstD211) and three 3-ketosteroid-9a-hydroxylases (Ksh; group 5: KshA226, KshA395 and KshB122). A gene cluster encoding Mon164, KstD211, KshA226, KshB122 and fatty acid ß-oxidoreductases constituted one integrated metabolic pathway, while genes encoding other key enzymes were sporadically distributed. All key enzymes except those from group 3 were prepared as recombinant proteins and their activities were evaluated, and the proteins exhibited distinct activities compared with enzymes identified from other bacterial species. Importantly, we found that the KstD211 and KshA395 enzymes in the HGMS2 strain retained weak activities and caused the occurrence of two major impurities, i.e., 1,4-androstene-3,17-dione (ADD) and 9-hydroxyl-4-androstene-3,17-dione (9OH-AD) during ß-sitosterol fermentation. The concurrence of these two 4-AD analogs not only lowered 4-AD production yield but also hampered 4-AD purification. HGMS2 has the least number of genes encoding KstD and Ksh enzymes compared with current industrial strains. Therefore, HGMS2 could be a potent strain by which the 4-AD production yield could be enhanced by disabling the KstD211 and KshA395 enzymes. Our work also provides new insight into the engineering of the HGMS2 strain to produce ADD and 9OH-AD for industrial application.

20.
Nat Cell Biol ; 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33020597

RESUMO

PIWI-interacting RNAs (piRNAs) are abundantly expressed during cardiac hypertrophy. However, their functions and molecular mechanisms remain unknown. Here, we identified a cardiac-hypertrophy-associated piRNA (CHAPIR) that promotes pathological hypertrophy and cardiac remodelling by targeting METTL3-mediated N6-methyladenosine (m6A) methylation of Parp10 mRNA transcripts. CHAPIR deletion markedly attenuates cardiac hypertrophy and restores heart function, while administration of a CHAPIR mimic enhances the pathological hypertrophic response in pressure-overloaded mice. Mechanistically, CHAPIR-PIWIL4 complexes directly interact with METTL3 and block the m6A methylation of Parp10 mRNA transcripts, which upregulates PARP10 expression. The CHAPIR-dependent increase in PARP10 promotes the mono-ADP-ribosylation of GSK3ß and inhibits its kinase activity, which results in the accumulation of nuclear NFATC4 and the progression of pathological hypertrophy. Hence, our findings reveal that a piRNA-mediated RNA epigenetic mechanism is involved in the regulation of cardiac hypertrophy and that the CHAPIR-METTL3-PARP10-NFATC4 signalling axis could be therapeutically targeted for treating pathological hypertrophy and maladaptive cardiac remodelling.

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