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1.
Mol Hortic ; 4(1): 12, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38561782

RESUMO

Although there is increasing evidence suggesting that DNA methylation regulates seed development, the underlying mechanisms remain poorly understood. Therefore, we aimed to shed light on this by conducting whole-genome bisulfite sequencing using seeds from the large-seeded cultivar 'HZ' and the abortive-seeded cultivar 'NMC'. Our analysis revealed that the 'HZ' seeds exhibited a hypermethylation level compared to the 'NMC' seeds. Furthermore, we found that the genes associated with differentially methylated regions (DMRs) and differentially expressed genes (DEGs) were mainly enriched in the reactive oxygen species (ROS) metabolic pathway. To investigate this further, we conducted nitroblue tetrazolium (NBT) and 2,7-Dichlorodihydrofluorescein (DCF) staining, which demonstrated a significantly higher amount of ROS in the 'NMC' seeds compared to the 'HZ' seeds. Moreover, we identified that the gene LcGPX6, involved in ROS scavenging, exhibited hypermethylation levels and parallelly lower expression levels in 'NMC' seeds compared to 'HZ' seeds. Interestingly, the ectopic expression of LcGPX6 in Arabidopsis enhanced ROS scavenging and resulted in lower seed production. Together, we suggest that DNA methylation-mediated ROS production plays a significant role in seed development in litchi, during which hypermethylation levels of LcGPX6 might repress its expression, resulting in the accumulation of excessive ROS and ultimately leading to seed abortion.

2.
J Integr Plant Biol ; 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38517216

RESUMO

At the physiological level, the interplay between auxin and ethylene has long been recognized as crucial for the regulation of organ abscission in plants. However, the underlying molecular mechanisms remain unknown. Here, we identified transcription factors involved in indoleacetic acid (IAA) and ethylene (ET) signaling that directly regulate the expression of INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and its receptor HAESA (HAE), which are key components initiating abscission. Specifically, litchi IDA-like 1 (LcIDL1) interacts with the receptor HAESA-like 2 (LcHSL2). Through in vitro and in vivo experiments, we determined that the auxin response factor LcARF5 directly binds and activates both LcIDL1 and LcHSL2. Furthermore, we found that the ETHYLENE INSENSITIVE 3-like transcription factor LcEIL3 directly binds and activates LcIDL1. The expression of IDA and HSL2 homologs was enhanced in LcARF5 and LcEIL3 transgenic Arabidopsis plants, but reduced in ein3 eil1 mutants. Consistently, the expressions of LcIDL1 and LcHSL2 were significantly decreased in LcARF5- and LcEIL3-silenced fruitlet abscission zones (FAZ), which correlated with a lower rate of fruitlet abscission. Depletion of auxin led to an increase in 1-aminocyclopropane-1-carboxylic acid (the precursor of ethylene) levels in the litchi FAZ, followed by abscission activation. Throughout this process, LcARF5 and LcEIL3 were induced in the FAZ. Collectively, our findings suggest that the molecular interactions between litchi AUXIN RESPONSE FACTOR 5 (LcARF5)-LcIDL1/LcHSL2 and LcEIL3-LcIDL1 signaling modules play a role in regulating fruitlet abscission in litchi and provide a long-sought mechanistic explanation for how the interplay between auxin and ethylene is translated into the molecular events that initiate abscission.

3.
Sci Rep ; 14(1): 4066, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38374193

RESUMO

Present studies show that steel fibres can improve the bond of steel bar in steel fibre reinforced concrete (SFRC) with a correlation to the fibre factor and the fibre distribution uniformity. As a foundation of high-flowability SFRC working together with 400 MPa grade hot-rolled ribbed (HRB400) steel bar in reinforced structures, the bond between them was evaluated through a series of pull-out testing on 48 specimens with a central arranged steel bar. The bond behaviours of steel bar were estimated with a constant bond length of 5d (d is the diameter of steel bar) embedded in high-flowability SFRC, the main research parameters included the ingot mill steel fibres with a fibre volume fraction varied from 0.8 to 2.0%, the strength grade C40 and C50 of SFRC or referenced conventional concrete, and the diameter of steel bars varied from 14 to 20 mm. Results showed that the high-flowability SFRC compacted with a slight vibration is beneficial to improve the bond failure pattern since steel fibres effectively eliminate the crack appeared on the SFRC blocks during the pulling out of steel bar, leading to all specimens failed with the steel bar pull out of SFRC blocks. The bond strength was dominant by the SFRC strength, and obviously strengthened with the increase of fibre volume fraction, while the peak-slip was slightly influenced by the diameter of steel bar. By conducting analyses of test data, equations for calculating the bond strength and the peak-slip are proposed accounting for the effect of steel fibres. Then the predicting method for the anchorage length is suggested linking with different design codes for concrete structures. Compared with test results of this study, a little shorter anchorage length of steel bar in SFRC is obtained from the specification of Chinese code JGJ/T46, which should be noticed to ensure a rational anchorage of ribbed steel bar in SFRC with ingot mill steel fibres.

4.
Plant Biotechnol J ; 22(4): 819-832, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37966709

RESUMO

MicroRNA482/2118 (miR482/2118) is a 22-nt miRNA superfamily, with conserved functions in disease resistance and plant development. It usually instigates the production of phased small interfering RNAs (phasiRNAs) from its targets to expand or reinforce its silencing effect. Using a new high-quality reference genome sequence and comprehensive small RNA profiling, we characterized a newly evolved regulatory pathway of miR482/2118 in litchi. In this pathway, miR482/2118 cleaved a novel noncoding trans-acting gene (LcTASL1) and triggered phasiRNAs to regulate the expression of gibberellin (GA) receptor gene GIBBERELLIN INSENSITIVE DWARF1 (GID1) in trans; another trans-acting gene LcTASL2, targeted by LcTASL1-derived phasiRNAs, produced phasiRNAs as well to target LcGID1 to reinforce the silencing effect of LcTASL1. We found this miR482/2118-TASL-GID1 pathway was likely involved in fruit development, especially the seed development in litchi. In vivo construction of the miR482a-TASL-GID1 pathway in Arabidopsis could lead to defects in flower and silique development, analogous to the phenotype of gid1 mutants. Finally, we found that a GA-responsive transcription factor, LcGAMYB33, could regulate LcMIR482/2118 as a feedback mechanism of the sRNA-silencing pathway. Our results deciphered a lineage-specifically evolved regulatory module of miR482/2118, demonstrating the high dynamics of miR482/2118 function in plants.


Assuntos
Arabidopsis , MicroRNAs , RNA Interferente Pequeno/genética , Giberelinas/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Plantas/genética , Sementes/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/genética , RNA de Plantas/genética
5.
J Exp Bot ; 75(3): 868-882, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-37891009

RESUMO

The gene regulatory networks that govern seed development are complex, yet very little is known about the genes and processes that are controlled by DNA methylation. Here, we performed single-base resolution DNA methylome analysis and found that CHH methylation increased significantly throughout seed development in litchi. Based on the association analysis of differentially methylated regions and weighted gene co-expression network analysis (WGCNA), 46 genes were identified as essential DNA methylation-regulated candidate genes involved in litchi seed development, including LcSR45, a homolog of the serine/arginine-rich (SR) splicing regulator SR45. LcSR45 is predominately expressed in the funicle, embryo, and seed integument, and displayed increased CHH methylation in the promoter during seed development. Notably, silencing of LcSR45 in a seed-aborted litchi cultivar significantly improved normal seed development, whereas the ectopic expression of LcSR45 in Arabidopsis caused seed abortion. Furthermore, LcSR45-dependent alternative splicing events were found to regulate genes involved in seed development. Together, our findings demonstrate that LcSR45 is hypermethylated, and plays a detrimental role in litchi seed development, indicating a global increase in DNA methylation at this stage.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Litchi , Litchi/genética , Litchi/metabolismo , Metilação de DNA , Splicing de RNA , Sementes , Frutas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Arabidopsis/metabolismo
7.
bioRxiv ; 2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37693440

RESUMO

Fluxes in human intra- and extracellular copper levels recently garnered attention for roles in cellular signaling, including affecting levels of the signaling molecule cyclic adenosine monophosphate (cAMP). We herein applied an unbiased temporal evaluation of the whole-genome transcriptional activities modulated by fluctuations in copper levels to identify the copper sensor proteins responsible for driving these activities. We found that fluctuations in physiologically-relevant copper levels rapidly modulate EGFR/MAPK/ERK signal transduction and activation of the transcription factor cAMP response element-binding protein (CREB). Both intracellular and extracellular assays support Cu 1+ inhibition of the EGFR-phosphatase PTPN2 (and potentially the homologous PTPN1)-via direct ligation to the PTPN2 active site cysteine side chain-as the underlying mechanism of copper-stimulated EGFR signal transduction activation. Depletion of copper represses this signaling pathway. We additionally show i ) copper supplementation drives transcriptional repression of the copper importer CTR1 and ii ) CREB activity is inversely correlated with CTR1 expression. In summary, our study reveals PTPN2 as a physiological copper sensor and defines a regulatory mechanism linking feedback control of copper-stimulated MAPK/ERK/CREB-signaling and CTR1 expression, thereby uncovering a previously unrecognized link between copper levels and cellular signal transduction.

8.
Int J Biol Macromol ; 250: 126264, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37572813

RESUMO

Phytohormone ethylene is well-known in positive modulation of plant organ abscission. However, the molecular mechanism underlying ethylene-induced abscission remains largely unknown. Here, we identified an ethylene-responsive factor, LcERF10, as a key regulatory gene in litchi fruitlet abscission. LcERF10 was strongly induced in the fruitlet abscission zone (FAZ) during the ethylene-activated abscission. Silencing of LcERF10 in litchi weakened the cytosolic alkalization of the FAZ and reduced fruitlet abscission. Moreover, LcERF10 directly bound the promoter and repressed the expression of LcNHX7, a Na+/H+ exchanger that was down-regulated in FAZ following the ethylene-activated abscission and up-regulated after LcERF10 silencing. Additionally, ectopic expression of LcERF10 in Arabidopsis promoted the cytosolic alkalization of the floral organ AZ and accelerated the floral organ abscission. Collectively, our results suggest that the transcription factor LcERF10 plays a positive role in litchi fruitlet abscission.

9.
Genes Dis ; 10(4): 1564-1581, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37397520

RESUMO

Glaucoma is the leading cause of irreversible blindness worldwide. In the pathogenesis of glaucoma, activated microglia can lead to retinal ganglion cells (RGCs) apoptosis and death, however, the molecular mechanisms remain largely unknown. We demonstrate that phospholipid scramblase 1 (PLSCR1) is a key regulator promoting RGCs apoptosis and their clearance by microglia. As evidenced in retinal progenitor cells and RGCs of the acute ocular hypertension (AOH) mouse model, overexpressed PLSCR1 induced its translocation from the nucleus to the cytoplasm and cytomembrane, as well as elevated phosphatidylserine exposure and reactive oxygen species generation with subsequent RGCs apoptosis and death. These damages were effectively attenuated by PLSCR1 inhibition. In the AOH model, PLSCR1 led to an increase in M1 type microglia activation and retinal neuroinflammation. Upregulation of PLSCR1 resulted in strongly elevated phagocytosis of apoptotic RGCs by activated microglia. Taken together, our study provides important insights linking activated microglia to RGCs death in the glaucoma pathogenesis and other RGC-related neurodegenerative diseases.

10.
Nat Chem Biol ; 19(11): 1384-1393, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37400536

RESUMO

Compact CRISPR-Cas systems offer versatile treatment options for genetic disorders, but their application is often limited by modest gene-editing activity. Here we present enAsCas12f, an engineered RNA-guided DNA endonuclease up to 11.3-fold more potent than its parent protein, AsCas12f, and one-third of the size of SpCas9. enAsCas12f shows higher DNA cleavage activity than wild-type AsCas12f in vitro and functions broadly in human cells, delivering up to 69.8% insertions and deletions at user-specified genomic loci. Minimal off-target editing is observed with enAsCas12f, suggesting that boosted on-target activity does not impair genome-wide specificity. We determine the cryo-electron microscopy (cryo-EM) structure of the AsCas12f-sgRNA-DNA complex at a resolution of 2.9 Å, which reveals dimerization-mediated substrate recognition and cleavage. Structure-guided single guide RNA (sgRNA) engineering leads to sgRNA-v2, which is 33% shorter than the full-length sgRNA, but with on par activity. Together, the engineered hypercompact AsCas12f system enables robust and faithful gene editing in mammalian cells.


Assuntos
Edição de Genes , RNA Guia de Sistemas CRISPR-Cas , Animais , Humanos , Microscopia Crioeletrônica , Sistemas CRISPR-Cas/genética , DNA/química , Mamíferos/genética
11.
Cell Commun Signal ; 21(1): 134, 2023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37316948

RESUMO

BACKGROUND: Age-related macular degeneration (AMD), characterized by the degeneration of retinal pigment epithelium (RPE) and photoreceptors, is the leading cause of irreversible vision impairment among the elderly. RPE senescence is an important contributor to AMD and has become a potential target for AMD therapy. HTRA1 is one of the most significant susceptibility genes in AMD, however, the correlation between HTRA1 and RPE senescence hasn't been investigated in the pathogenesis of AMD. METHODS: Western blotting and immunohistochemistry were used to detect HTRA1 expression in WT and transgenic mice overexpressing human HTRA1 (hHTRA1-Tg mice). RT-qPCR was used to detect the SASP in hHTRA1-Tg mice and ARPE-19 cells infected with HTRA1. TEM, SA-ß-gal was used to detect the mitochondria and senescence in RPE. Retinal degeneration of mice was investigated by fundus photography, FFA, SD-OCT and ERG. The RNA-Seq dataset of ARPE-19 cells treated with adv-HTRA1 versus adv-NC were analyzed. Mitochondrial respiration and glycolytic capacity in ARPE-19 cells were measured using OCR and ECAR. Hypoxia of ARPE-19 cells was detected using EF5 Hypoxia Detection Kit. KC7F2 was used to reduce the HIF1α expression both in vitro and in vivo. RESULTS: In our study, we found that RPE senescence was facilitated in hHTRA1-Tg mice. And hHTRA1-Tg mice became more susceptible to NaIO3 in the development of oxidative stress-induced retinal degeneration. Similarly, overexpression of HTRA1 in ARPE-19 cells accelerated cellular senescence. Our RNA-seq revealed an overlap between HTRA1-induced differentially expressed genes associated with aging and those involved in mitochondrial function and hypoxia response in ARPE-19 cells. HTRA1 overexpression in ARPE-19 cells impaired mitochondrial function and augmented glycolytic capacity. Importantly, upregulation of HTRA1 remarkably activated HIF-1 signaling, shown as promoting HIF1α expression which mainly located in the nucleus. HIF1α translation inhibitor KC7F2 significantly prevented HTRA1-induced cellular senescence in ARPE-19 cells, as well as improved the visual function in hHTRA1-Tg mice treated with NaIO3. CONCLUSIONS: Our study showed elevated HTRA1 contributes to the pathogenesis of AMD by promoting cellular senescence in RPE through damaging mitochondrial function and activating HIF-1 signaling. It also pointed out that inhibition of HIF-1 signaling might serve as a potential therapeutic strategy for AMD. Video Abstract.


Assuntos
Degeneração Retiniana , Idoso , Humanos , Animais , Camundongos , Epitélio Pigmentado da Retina , Transdução de Sinais , Mitocôndrias , Núcleo Celular
12.
Materials (Basel) ; 16(10)2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37241292

RESUMO

Remote-pumped concrete for infrastructure construction is a key innovation of the mechanized and intelligent construction technology. This has brought steel-fiber-reinforced concrete (SFRC) into undergoing various developments, from conventional flowability to high pumpability with low-carbon features. In this regard, an experimental study on the mixing proportion design and the pumpability and mechanical properties of SFRC was conducted for remote pumping. Using the absolute volume method based on the steel-fiber-aggregate skeleton packing test, the water dosage and the sand ratio were adjusted with an experimental study on reference concrete with the premise of varying the volume fraction of steel fiber from 0.4% to 1.2%. The test results of the pumpability of fresh SFRC indicated that the pressure bleeding rate and the static segregation rate were not the controlling indices due to the fact that they were far below the limits of the specifications, and the slump flowability fitted for remote-pumping construction was verified by a lab pumping test. Although the rheological properties of the SFRC charactered by the yield stress and the plastic viscosity increased with the volume fraction of steel fiber, those of mortar used as a lubricating layer during the pumping was almost constant. The cubic compressive strength of the SFRC had a tendency to increase with the volume fraction of steel fiber. The reinforcement effect of steel fiber on the splitting tensile strength of the SFRC was similar to the specifications, while its effect on the flexural strength was higher than the specifications due to the special feature of steel fibers distributed along the longitudinal direction of the beam specimens. The SFRC had excellent impact resistance with an increased volume fraction of steel fiber and presented acceptable water impermeability.

13.
Cell ; 186(9): 1817-1818, 2023 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-37116466

RESUMO

Proper regulation of protein degradation is essential for cell physiology. In the current issue of Cell, Baek et al. elucidated how a large class of ubiquitin ligase, known as CRL, is assembled and disassembled through a key regulator, CAND1.


Assuntos
Fatores de Transcrição , Ubiquitina-Proteína Ligases , Proteínas Culina/metabolismo , Proteólise , Fatores de Transcrição/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
14.
Ann Transl Med ; 11(1): 3, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36760251

RESUMO

Background: Retinal ischemia-reperfusion (RIR) is a common pathological condition that can lead to retinal ganglion cell (RGC) death and visual impairment. However, the pathogenesis of RGC loss and visual impairment caused by retinal ischemia remains unclear. Methods: A mouse model of elevated intraocular pressure (IOP)-induced RIR injury was used. Flash visual evoked potentials (FVEPs) and electroretinography (ERG) recordings were performed to assess visual function. The structural integrity of the retina and the number of RGC were assessed using hematoxylin and eosin (HE) staining and retinal flat mounts. Ferroptosis was evaluated by testing the levels of glutathione (GSH), malondialdehyde (MDA), glutathione peroxidase (GPX4), and ferritin light chains (FTL) in the retina of wild-type (WT) and lipocalin-2 transgenic (LCN2-TG) mice after RIR injury. Results: We found that LCN2 was mainly expressed in the RGC layer in the retina of wild-type mice and remarkably upregulated after RIR injury. Compared with wild-type mice, aggravated RGC death and visual impairment were exhibited in LCN2-TG mice with RIR injury. Moreover, LCN2 overexpression activated glial cells and upregulated proinflammatory factors. More importantly, we found that LCN2 strongly promoted ferroptosis signaling in RGC death and visual impairment. Liproxstatin-1, an inhibitor of ferroptosis, could significantly ameliorate RGC death and visual impairment. Furthermore, we found significantly alleviated RGC death and retinal damage in LCN2 heterozygous knockout mice. Conclusions: Our study provides important insights linking upregulated LCN2-mediated promotion of ferroptosis to RGC death and visual function impairment in the pathogenesis of ischemic retinopathy.

15.
Brief Bioinform ; 24(2)2023 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-36682003

RESUMO

Cryo-electron microscopy (cryo-EM) allows a macromolecular structure such as protein-DNA/RNA complexes to be reconstructed in a three-dimensional coulomb potential map. The structural information of these macromolecular complexes forms the foundation for understanding the molecular mechanism including many human diseases. However, the model building of large macromolecular complexes is often difficult and time-consuming. We recently developed DeepTracer-2.0, an artificial-intelligence-based pipeline that can build amino acid and nucleic acid backbones from a single cryo-EM map, and even predict the best-fitting residues according to the density of side chains. The experiments showed improved accuracy and efficiency when benchmarking the performance on independent experimental maps of protein-DNA/RNA complexes and demonstrated the promising future of macromolecular modeling from cryo-EM maps. Our method and pipeline could benefit researchers worldwide who work in molecular biomedicine and drug discovery, and substantially increase the throughput of the cryo-EM model building. The pipeline has been integrated into the web portal https://deeptracer.uw.edu/.


Assuntos
DNA , RNA , Humanos , Microscopia Crioeletrônica/métodos , Modelos Moleculares , Conformação Proteica , Substâncias Macromoleculares/química
16.
Plant J ; 113(5): 954-968, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36587275

RESUMO

Reactive oxygen species (ROS) have been emerging as a key regulator in plant organ abscission. However, the mechanism underlying the regulation of ROS homeostasis in the abscission zone (AZ) is not completely established. Here, we report that a DOF (DNA binding with one finger) transcription factor LcDOF5.6 can suppress the litchi fruitlet abscission through repressing the ROS accumulation in fruitlet AZ (FAZ). The expression of LcRbohD, a homolog of the Arabidopsis RBOHs that are critical for ROS production, was significantly increased during the litchi fruitlet abscission, in parallel with an increased accumulation of ROS in FAZ. In contrast, silencing of LcRbohD reduced the ROS accumulation in FAZ and decreased the fruitlet abscission in litchi. Using in vitro and in vivo assays, we revealed that LcDOF5.6 was shown to inhibit the expression of LcRbohD via direct binding to its promoter. Consistently, silencing of LcDOF5.6 increased the expression of LcRbohD, concurrently with higher ROS accumulation in FAZ and increased fruitlet abscission. Furthermore, the expression of key genes (LcIDL1, LcHSL2, LcACO2, LcACS1, and LcEIL3) in INFLORESCENCE DEFICIENT IN ABSCISSION signaling and ethylene pathways were altered in LcRbohD-silenced and LcDOF5.6-silenced FAZ cells. Taken together, our results demonstrate an important role of the LcDOF5.6-LcRbohD module during litchi fruitlet abscission. Our findings provide new insights into the molecular regulatory network of organ abscission.


Assuntos
Arabidopsis , Litchi , Espécies Reativas de Oxigênio/metabolismo , Litchi/genética , Litchi/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Frutas/genética , Frutas/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas
17.
Nat Commun ; 13(1): 7291, 2022 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-36435815

RESUMO

A critical step in lipopolysaccharide (LPS) biogenesis involves flipping lipooligosaccharide, an LPS precursor, from the cytoplasmic to the periplasmic leaflet of the inner membrane, an operation carried out by the ATP-binding cassette transporter MsbA. Although LPS binding to the inner cavity of MsbA is well established, the selectivity of MsbA-lipid interactions at other site(s) remains poorly understood. Here we use native mass spectrometry (MS) to characterize MsbA-lipid interactions and guide structural studies. We show the transporter co-purifies with copper(II) and metal binding modulates protein-lipid interactions. A 2.15 Å resolution structure of an N-terminal region of MsbA in complex with copper(II) is presented, revealing a structure reminiscent of the GHK peptide, a high-affinity copper(II) chelator. Our results demonstrate conformation-dependent lipid binding affinities, particularly for the LPS-precursor, 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)2-lipid A (KDL). We report a 3.6 Å-resolution structure of MsbA trapped in an open, outward-facing conformation with adenosine 5'-diphosphate and vanadate, revealing a distinct KDL binding site, wherein the lipid forms extensive interactions with the transporter. Additional studies provide evidence that the exterior KDL binding site is conserved and a positive allosteric modulator of ATPase activity, serving as a feedforward activation mechanism to couple transporter activity with LPS biosynthesis.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Lipopolissacarídeos , Transportadores de Cassetes de Ligação de ATP/metabolismo , Lipopolissacarídeos/metabolismo , Cobre/metabolismo , Escherichia coli/metabolismo , Proteínas de Bactérias/metabolismo , Difosfato de Adenosina/metabolismo
18.
J Med Chem ; 65(17): 11745-11758, 2022 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-36007247

RESUMO

Based on the synergistic therapeutic effect of nitric oxide (NO) and Rho-associated protein kinase (ROCK) inhibitors on glaucoma, a new group of NO-donating ripasudil derivatives RNO-1-RNO-6 was designed, synthesized, and biologically evaluated. The results demonstrated that the most active compound RNO-6 maintained potent ROCK inhibitory and NO releasing abilities, reversibly depolymerized F-actin, and suppressed mitochondrial respiration in human trabecular meshwork (HTM) cells. Topical administration of RNO-6 (0.26%) in chronic ocular hypertension glaucoma mice exhibited significant IOP lowering and visual function and retinal ganglion cell (RGC) protection activities, superior to an equal molar dose of ripasudil. RNO-6 could be a promising agent for glaucoma or ocular hypertension, warranting further investigation.


Assuntos
Glaucoma , Hipertensão Ocular , Animais , Glaucoma/tratamento farmacológico , Humanos , Pressão Intraocular , Isoquinolinas , Camundongos , Óxido Nítrico , Hipertensão Ocular/tratamento farmacológico , Células Ganglionares da Retina , Sulfonamidas , Quinases Associadas a rho
19.
Exp Eye Res ; 221: 109142, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35691375

RESUMO

Diabetic retinopathy (DR) is one of the most common blindness in working-age adults. Transcription factor 7 like 2 (TCF7L2) is a susceptibility gene of DR, however, its roles in the pathogenesis of DR are still largely unknown. In this study, we found that TCF7L2 was mainly located in the cell nucleus of retinal ganglion cell layer (GCL) and inner nuclear layer (INL), while it was not expressed in the cell nucleus of retinal outer nuclear layer (ONL). Expression of TCF7L2 was significantly elevated in the retinas of db/db diabetic mice and oxygen-induced retinopathy (OIR) mice. Also, in Ad-hTCF7L2 treated hiPSCs-derived retinal progenitor cells (RPCs), activating transcription factor 6 (ATF6)-related endoplasmic reticulum (ER) stress signaling was remarkably activated. Moreover, knockdown of TCF7L2 significantly inhibited ATF6-related ER stress signaling. Furthermore, the data of endothelial permeability assay showed that RPCs pretreated with Ad-hTCF7L2 lead to enhanced monolayer permeability of human umbilical vein endothelial cells (HUVECs), and knockdown of TCF7L2 or ATF6 in RPCs could alleviate the monolayer permeability of HUVECs. Thus, our results showed that TCF7L2 could trigger ATF6-related ER stress signaling and promote vein endothelial cell permeability, which will provide important insight into the role of TCF7L2 in the pathogenesis of DR and contribute to designing potential therapies.


Assuntos
Diabetes Mellitus Experimental , Retinopatia Diabética , Estresse do Retículo Endoplasmático , Proteína 2 Semelhante ao Fator 7 de Transcrição , Animais , Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/metabolismo , Estresse do Retículo Endoplasmático/genética , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Camundongos , Transdução de Sinais/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/metabolismo
20.
Nat Commun ; 13(1): 2444, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35508534

RESUMO

A large coercive field (EC) and ultrahigh piezoelectricity are essential for ferroelectrics used in high-drive electromechanical applications. The discovery of relaxor-PbTiO3 crystals is a recent breakthrough; they currently afford the highest piezoelectricity, but usually with a low EC. Such performance deterioration occurs because high piezoelectricity is interlinked with an easy polarization rotation, subsequently favoring a dipole switch under small fields. Therefore, the search for ferroelectrics with both a large EC and ultrahigh piezoelectricity has become an imminent challenge. Herein, ternary Pb(Sc1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals are reported, wherein the dispersed local heterogeneity comprises abundant tetragonal phases, affording a EC of 8.2 kV/cm (greater than that of Pb(Mg1/3Nb2/3)O3-PbTiO3 by a factor of three) and ultrahigh piezoelectricity (d33 = 2630 pC/N; d15 = 490 pC/N). The observed EC enhancement is the largest reported for ultrahigh-piezoelectric materials, providing a simple, practical, and universal route for improving functionalities in ferroelectrics with an atomic-level understanding.

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