Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.948
Filtrar
Más filtros

Intervalo de año de publicación
1.
Immunity ; 55(11): 2187-2205.e5, 2022 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-36351376

RESUMEN

Bats are reservoir hosts of many zoonotic viruses with pandemic potential. We utilized single-cell transcriptome sequencing (scRNA-seq) to analyze the immune response in bat lungs upon in vivo infection with a double-stranded RNA virus, Pteropine orthoreovirus PRV3M. Bat neutrophils were distinguished by high basal IDO1 expression. NK cells and T cells were the most abundant immune cells in lung tissue. Three distinct CD8+ effector T cell populations could be delineated by differential expression of KLRB1, GFRA2, and DPP4. Select NK and T clusters increased expression of genes involved in T cell activation and effector function early after viral infection. Alveolar macrophages and classical monocytes drove antiviral interferon signaling. Infection expanded a CSF1R+ population expressing collagen-like genes, which became the predominant myeloid cell type post-infection. This work uncovers features relevant to viral disease tolerance in bats, lays a foundation for future experimental work, and serves as a resource for comparative immunology studies.


Asunto(s)
Quirópteros , Virosis , Animales , Quirópteros/genética , Néctar de las Plantas , Transcriptoma , Análisis de la Célula Individual , Perfilación de la Expresión Génica
2.
EMBO J ; 43(20): 4542-4577, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39192031

RESUMEN

Heterochromatin, a key component of the eukaryotic nucleus, is fundamental to the regulation of genome stability, gene expression and cellular functions. However, the factors and mechanisms involved in heterochromatin formation and maintenance still remain largely unknown. Here, we show that insulin receptor tyrosine kinase substrate (IRTKS), an I-BAR domain protein, is indispensable for constitutive heterochromatin formation via liquid‒liquid phase separation (LLPS). In particular, IRTKS droplets can infiltrate heterochromatin condensates composed of HP1α and diverse DNA-bound nucleosomes. IRTKS can stabilize HP1α by recruiting the E2 ligase Ubc9 to SUMOylate HP1α, which enables it to form larger phase-separated droplets than unmodified HP1α. Furthermore, IRTKS deficiency leads to loss of heterochromatin, resulting in genome-wide changes in chromatin accessibility and aberrant transcription of repetitive DNA elements. This leads to activation of cGAS-STING pathway and type-I interferon (IFN-I) signaling, as well as to the induction of cellular senescence and senescence-associated secretory phenotype (SASP) responses. Collectively, our findings establish a mechanism by which IRTKS condensates consolidate constitutive heterochromatin, revealing an unexpected role of IRTKS as an epigenetic mediator of cellular senescence.


Asunto(s)
Senescencia Celular , Homólogo de la Proteína Chromobox 5 , Heterocromatina , Animales , Humanos , Ratones , Ensamble y Desensamble de Cromatina , Homólogo de la Proteína Chromobox 5/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , Heterocromatina/metabolismo , Heterocromatina/genética , Transducción de Señal
3.
EMBO Rep ; 25(10): 4337-4357, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39242776

RESUMEN

Despite the efficacy of highly active antiretroviral therapy in controlling the incidence and mortality of AIDS, effective interventions for HIV-1-induced neurological damage and cognitive impairment remain elusive. In this study, we found that HIV-1 infection can induce proteolytic cleavage and aberrant aggregation of TAR DNA-binding protein 43 (TDP-43), a pathological protein associated with various severe neurological disorders. The HIV-1 accessory protein Vpu was found to be responsible for the cleavage of TDP-43, as ectopic expression of Vpu alone was sufficient to induce TDP-43 cleavage, whereas HIV-1 lacking Vpu failed to cleave TDP-43. Mechanistically, the cleavage of TDP-43 at Asp89 by HIV-1 relies on Vpu-mediated activation of Caspase 3, and pharmacological inhibition of Caspase 3 activity effectively suppressed the HIV-1-induced aggregation and neurotoxicity of TDP-43. Overall, these results suggest that TDP-43 is a conserved host target of HIV-1 Vpu and provide evidence for the involvement of TDP-43 dysregulation in the neural pathogenesis of HIV-1.


Asunto(s)
Caspasa 3 , Proteínas de Unión al ADN , VIH-1 , Proteínas del Virus de la Inmunodeficiencia Humana , Proteolisis , Proteínas Reguladoras y Accesorias Virales , Humanos , Caspasa 3/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Células HEK293 , Infecciones por VIH/metabolismo , Infecciones por VIH/virología , Infecciones por VIH/tratamiento farmacológico , Proteínas del Virus de la Inmunodeficiencia Humana/metabolismo , Proteínas del Virus de la Inmunodeficiencia Humana/genética , Neuronas/metabolismo , Neuronas/virología , Proteínas Reguladoras y Accesorias Virales/metabolismo
4.
J Virol ; 98(2): e0190923, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38289118

RESUMEN

Pyroptosis, a pro-inflammatory programmed cell death, has been implicated in the pathogenesis of coronavirus disease 2019 and other viral diseases. Gasdermin family proteins (GSDMs), including GSDMD and GSDME, are key regulators of pyroptotic cell death. However, the mechanisms by which virus infection modulates pyroptosis remain unclear. Here, we employed a mCherry-GSDMD fluorescent reporter assay to screen for viral proteins that impede the localization and function of GSDMD in living cells. Our data indicated that the main protease NSP5 of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) blocked GSDMD-mediated pyroptosis via cleaving residues Q29 and Q193 of GSDMD. While another SARS-CoV-2 protease, NSP3, cleaved GSDME at residue G370 but activated GSDME-mediated pyroptosis. Interestingly, respiratory enterovirus EV-D68-encoded proteases 3C and 2A also exhibit similar differential regulation on the functions of GSDMs by inactivating GSDMD but initiating GSDME-mediated pyroptosis. EV-D68 infection exerted oncolytic effects on human cancer cells by inducing pyroptotic cell death. Our findings provide insights into how respiratory viruses manipulate host cell pyroptosis and suggest potential targets for antiviral therapy as well as cancer treatment.IMPORTANCEPyroptosis plays a crucial role in the pathogenesis of coronavirus disease 2019, and comprehending its function may facilitate the development of novel therapeutic strategies. This study aims to explore how viral-encoded proteases modulate pyroptosis. We investigated the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and respiratory enterovirus D68 (EV-D68) proteases on host cell pyroptosis. We found that SARS-CoV-2-encoded proteases NSP5 and NSP3 inactivate gasdermin D (GSDMD) but initiate gasdermin E (GSDME)-mediated pyroptosis, respectively. We also discovered that another respiratory virus EV-D68 encodes two distinct proteases 2A and 3C that selectively trigger GSDME-mediated pyroptosis while suppressing the function of GSDMD. Based on these findings, we further noted that EV-D68 infection triggers pyroptosis and produces oncolytic effects in human carcinoma cells. Our study provides new insights into the molecular mechanisms underlying virus-modulated pyroptosis and identifies potential targets for the development of antiviral and cancer therapeutics.


Asunto(s)
Endopeptidasas , Enterovirus Humano D , Interacciones Microbiota-Huesped , Virus Oncolíticos , Piroptosis , SARS-CoV-2 , Humanos , Línea Celular Tumoral , COVID-19/metabolismo , COVID-19/terapia , COVID-19/virología , Endopeptidasas/genética , Endopeptidasas/metabolismo , Enterovirus Humano D/enzimología , Enterovirus Humano D/genética , Infecciones por Enterovirus/metabolismo , Infecciones por Enterovirus/virología , Gasderminas/antagonistas & inhibidores , Gasderminas/genética , Gasderminas/metabolismo , Viroterapia Oncolítica , Virus Oncolíticos/enzimología , Virus Oncolíticos/genética , SARS-CoV-2/enzimología , SARS-CoV-2/genética , Proteínas Virales/genética , Proteínas Virales/metabolismo
5.
Plant Physiol ; 196(1): 564-578, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-38753299

RESUMEN

The transcriptional regulation of aluminum (Al) tolerance in plants is largely unknown, although Al toxicity restricts agricultural yields in acidic soils. Here, we identified a NAM, ATAF1/2, and cup-shaped cotyledon 2 (NAC) transcription factor that participates in Al tolerance in Arabidopsis (Arabidopsis thaliana). Al substantially induced the transcript and protein levels of ANAC070, and loss-of-function mutants showed remarkably increased Al sensitivity, implying a beneficial role of ANAC070 in plant tolerance to Al toxicity. Further investigation revealed that more Al accumulated in the roots of anac070 mutants, especially in root cell walls, accompanied by a higher hemicellulose and xyloglucan level, implying a possible interaction between ANAC070 and genes that encode proteins responsible for the modification of xyloglucan, including xyloglucan endo-transglycosylase/hydrolase (XTH) or ANAC017. Yeast 1-hybrid analysis revealed a potential interaction between ANAC070 and ANAC017, but not for other XTHs. Furthermore, dual-luciferase reporter assay, RT-qPCR, and GUS analysis revealed that ANAC070 could directly repress the transcript levels of ANAC017, and knockout of ANAC017 in the anac070 mutant partially restored its Al sensitivity phenotype, indicating that ANAC070 contributes to Al tolerance mechanisms other than suppression of ANAC017 expression. Further analysis revealed that the core transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) and its target genes, which control Al tolerance in Arabidopsis, may also be involved in ANAC070-regulated Al tolerance. In summary, we identified a transcription factor, ANAC070, that represses the ANAC017-XTH31 module to regulate Al tolerance in Arabidopsis.


Asunto(s)
Aluminio , Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Glucanos , Factores de Transcripción , Xilanos , Aluminio/toxicidad , Arabidopsis/genética , Arabidopsis/efectos de los fármacos , Arabidopsis/fisiología , Arabidopsis/metabolismo , Glucanos/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Xilanos/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Raíces de Plantas/genética , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Pared Celular/metabolismo , Pared Celular/efectos de los fármacos , Pared Celular/genética , Mutación/genética
6.
Plant Physiol ; 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39405162

RESUMEN

Cultivated strawberry (Fragaria × ananassa) is a popular, economically important fruit. The ripening of the receptacle (pseudocarp), the main edible part, depends on endogenously produced abscisic acid (ABA) and is suppressed by the high level of auxin produced from achenes (true fruit) during early development. However, the mechanism whereby auxin regulates receptacle ripening through inhibiting ABA biosynthesis remains unclear. Here, we identified AUXIN RESPONSE FACTOR 2 (FaARF2), which showed decreased expression with reduced auxin content in the receptacle, leading to increased ABA levels and accelerated ripening. Dual-luciferase, yeast one-hybrid, and electrophoretic mobility shift assays demonstrated that FaARF2 could bind to the AuxRE element in the promoter of 9-CIS-EPOXYCAROT-ENOID DIOXYGENASE 1 (FaNCED1), a key ABA biosynthetic gene, to suppress its transcriptional activity. Transiently overexpressing FaARF2 in the receptacles decreased FaNCED1 expression and ABA levels, resulting in inhibition of receptacle ripening and of development of quality attributes, such as pigmentation, aroma, and sweetness. This inhibition caused by overexpressing FaARF2 was partially recovered by the injection of exogenous ABA; conversely, transient silencing of FaARF2 using RNA interference produced the opposite results. The negative targeting of FaNCED1 by FaARF2 is a key link between auxin-ABA interactions and regulation of strawberry ripening.

7.
Nano Lett ; 24(42): 13333-13340, 2024 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-39361829

RESUMEN

Chiral microlasers hold great promise for optoelectronics from integrated photonic devices to high-density quantum information processing. Despite significant progress in lead-halide perovskite emitters, chiral lasing with high dissymmetry factors (glum) has not yet been realized. Here, we demonstrate chiral single-mode microlasers with exceptional stability and tunable emission across the visible range by combining CsPbClxBr3-x perovskite microrods (MRs) with a cholesteric liquid crystal (CLC) layer. The MRs lase via a whispering gallery mode (WGM) microcavity and confer chirality through the encapsulated CLC layer, thus exhibiting circularly polarized lasing with dissymmetry factors reaching 1.62. Importantly, we demonstrate wavelength-tunable high dissymmetry chiral lasers in a broad spectral range by tuning the halide composition and using CLC layers with the desired photonic bandgap (PBG). This facile approach to generate chiral lasing not only is applicable to semiconductor nano- and microcrystals but also paves the way for potential integration into nanoscale photonic devices.

8.
J Biol Chem ; 299(8): 105019, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37422193

RESUMEN

Poly(A)-binding protein nuclear 1 (PABPN1) is an RNA-binding protein localized in nuclear speckles, while its alanine (Ala)-expanded variants accumulate as intranuclear aggregates in oculopharyngeal muscular dystrophy. The factors that drive PABPN1 aggregation and its cellular consequences remain largely unknown. Here, we investigated the roles of Ala stretch and poly(A) RNA in the phase transition of PABPN1 using biochemical and molecular cell biology methods. We have revealed that the Ala stretch controls its mobility in nuclear speckles, and Ala expansion leads to aggregation from the dynamic speckles. Poly(A) nucleotide is essential to the early-stage condensation that thereby facilitates speckle formation and transition to solid-like aggregates. Moreover, the PABPN1 aggregates can sequester CFIm25, a component of the pre-mRNA 3'-UTR processing complex, in an mRNA-dependent manner and consequently impair the function of CFIm25 in alternative polyadenylation. In conclusion, our study elucidates a molecular mechanism underlying PABPN1 aggregation and sequestration, which will be beneficial for understanding PABPN1 proteinopathy.


Asunto(s)
Distrofia Muscular Oculofaríngea , Poliadenilación , Humanos , Alanina/metabolismo , Distrofia Muscular Oculofaríngea/genética , Distrofia Muscular Oculofaríngea/metabolismo , Proteína I de Unión a Poli(A)/genética , Proteína I de Unión a Poli(A)/metabolismo , ARN/metabolismo
9.
Int J Cancer ; 2024 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-39499199

RESUMEN

Optimal cardiac dose constraints in breast cancer (BC) patients undergoing postoperative intensity-modulated radiation therapy (IMRT) are unclear, although as low as possible is recommended. This trial proposes serial cardiac dose constraint to optimize cardiac safety. Postoperative BC patients eligible for anthracycline/taxanes-based chemotherapy or HER2-targeted therapy were randomized to cardiac safety arm with prespecified mean heart dose (MHD) (≤6 Gy), V30 (≤20%), and V10 (≤50%) constraints, or to a control arm with in-house protocol (mainly MHD ≤8 Gy). The primary endpoint was cumulative incidence of newly onset cardiac events within 1-year post-RT. An exploratory analysis examined the relationship between whole heart dose metrics and those of substructures. Of 199 participants, 93 were in the cardiac safety and 106 in the control arm. The cardiac safety group showed lower MHD, V10, and V30. The 1-year cardiac event incidence was slightly lower in the cardiac safety group (19.4%) compared to controls (24.9%). The LVEF and diastolic dysfunction rates were 0% and 5.4% in the study arm, and 1.9% and 8.8% in the control arm, respectively. The LAD, LV, and RV received the highest doses for left-sided patients. For right-sided patients, RA, RCA, and RV were most irradiated. The MHD, V10, and Dmax of heart significantly correlated with all substructure doses in either laterality. Our study supports the early cardiac safety profile using IMRT in BC patients receiving cardiac-toxic systemic therapy, with serial cardiac dose constraints. Combined constraints on MHD and dose-volume parameters are representative of the cardiac substructure dose.

10.
Small ; 20(7): e2307619, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37803332

RESUMEN

Atomically precise metal nanoclusters (NCs) have garnered tremendous attention as light-harvesting antennas in heterogeneous photocatalysis due to unique atomic stacking mode, quantum confinement effect, and enriched active sites. However, metal NCs as photosensitizers suffer from extremely short carrier lifetime, poor photostability, and difficulty in carrier migration, which hinder the wide-spread utilization of metal NCs in solar energy conversion. To solve these problems, herein, Ag-doped glutathione (GSH)-capped gold NCs, i.e., alloy Au1- x Agx @GSH NCs and non-conjugated insulating polymer of poly(diallyl-dimethylammonium chloride) (PDDA) are utilized as the building blocks for layer-by-layer assembly of spatially multilayered alloy NCs/metal oxide (MO) photosystems. The alternately deposited ultrathin PDDA layer in-between Au1- x Agx @GSH NCs on the MO substrate functions as an efficient charge flow mediator to relay the directional photoelectron transfer over Au1- x Agx @GSH NCs, giving rise to the cascade charge transfer chain. This peculiar carrier migration mode endowed by exquisite interface configuration design significantly boosts the unidirectional electron migration from the Au1- x Agx @GSH NCs to the MO substrate, substantially improving the visible-light-driven photoelectrochemical water oxidation performances of MO/(PDDA-Au1- x Agx )n multilayer heterostructured photoanodes. The work will inspire the rational construction of alloy metal NCs-based photosystems for modulating spatially controllable charge transfer pathway for solar energy conversion.

11.
Small ; 20(35): e2400958, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38644328

RESUMEN

Quantum dots (QDs) colloidal nanocrystals are attracting enduring interest by scientific communities for solar energy conversion due to generic physicochemical merits including substantial light absorption coefficient, quantum confinement effect, enriched catalytically active sites, and tunable electronic structure. However, photo-induced charge carriers of QDs suffer from ultra-short charge lifespan and poor stability, rendering controllable vectorial charge modulation and customizing robust and stable QDs artificial photosystems challenging. Herein, tailor-made oppositely charged transition metal chalcogenides quantum dots (TMCs QDs) and MXene quantum dots (MQDs) are judiciously harnessed as the building blocks for electrostatic layer-by-layer assembly buildup on the metal oxides (MOs) framework. In these exquisitely designed LbL assembles MOs/(TMCs QDs/MQDs)n heterostructured photoanodes, TMCs QDs layer acts as light-harvesting antennas, and MQDs layer serves as electron-capturing mediator to relay cascade electrons from TMCs QDs to the MOs substrate, thereby yielding the spatially ordered tandem charge transport chain and contributing to the significantly boosted charge separation over TMCs QDs and solar water oxidation efficiency of MOs/(TMCs QDs/MQDs)n photoanodes. The relationship between interface configuration and charge transfer characteristics is unambiguously unlocked, by which photoelectrochemical mechanism is elucidated. This work would provide inspiring ideas for precisely mediating interfacial charge transfer pathways over QDs toward solar energy conversion.

12.
Small ; : e2405514, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39221645

RESUMEN

Rational construction of high-efficiency photoelectrodes with optimized carrier migration to the ideal active sites, is crucial for enhancing solar water oxidation. However, complexity in precisely modulating interface configuration and directional charge transfer pathways retards the design of robust and stable artificial photosystems. Herein, a straightforward yet effective strategy is developed for compact encapsulation of metal oxides (MOs) with an ultrathin non-conjugated polymer layer to modulate interfacial charge migration and separation. By periodically coating highly ordered TiO2 nanoarrays with oppositely charged polyelectrolyte of poly(dimethyl diallyl ammonium chloride) (PDDA), MOs/polymer composite photoanodes are readily fabricated under ambient conditions. It is verified that electrons photogenerated from the MOs substrate can be efficiently extracted by the ultrathin solid insulating PDDA layer, significantly boosting the carrier transport kinetics and enhancing charge separation of MOs, and thus triggering a remarkable enhancement in the solar water oxidation performance. The origins of the unexpected electron-withdrawing capability of such non-conjugated insulating polymer are unambiguously uncovered, and the scenario occurring at the interface of hybrid photoelectrodes is elucidated. The work would reinforce the fundamental understanding on the origins of generic charge transport capability of insulating polymer and benefit potential wide-spread utilization of insulating polymers as co-catalysts for solar energy conversion.

13.
Small ; : e2405228, 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39380390

RESUMEN

Cocatalyst is of paramount significance to provide fruitful active sites for suppressing the spatial charge recombination toward boosted photocatalysis. Up to date, exploration of robust and stable cocatalysts is remained challenging. Inspired by the intrinsic merits of single-atom catalysts (SACs), such as distinctive electronic structure and high atomic utilization efficiency, single-atom/transition metal chalcogenides (TMCs) is utilized as a model to synthesize CdS-Pd single-atom catalyst (CdS-PdSA) heterostructures. This demonstrates the precise anchoring of isolated metal single-atom catalysts (SACs) onto TMCs through a simple yet effective wet-chemical strategy. The resulting heterostructures exhibit significantly enhanced and stable photocatalytic activity for selective anaerobic organic transformations and hydrogen production under visible light. This enhancement is primarily inferred due to the role of Pd SACs as electron pumps, which directionally trap the electrons photoexcited over CdS, accelerating the spatial charge separation and prolonging the carrier lifespan. The charge transport route and photocatalytic mechanism are elucidated. This work underscores the potential of SACs as cocatalysts in heterogeneous photocatalysis, offering valuable insights for the rational design of atomic-level cocatalysts for solar-to-chemical energy conversion and beyond.

14.
Planta ; 259(3): 52, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38289400

RESUMEN

MAIN CONCLUSION: Auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al. In our previous study, we identified an unknown mechanism by which 1-naphthaleneacetic acid (NAA) decreased the fixation of aluminum (Al) in the cell wall. Here, we observed that external application of the nitric oxide (NO) donor S-nitrosoglutathion (GSNO) increased the inhibition of Al on root elongation. Further analysis indicated that GSNO could induce Al accumulation in the roots and root cell walls, which is consistent with lower xyloglucan content. In comparison to the Columbia-0 (Col-0) wild type (WT), endogenous NO-reduced mutants noa1 (NOA pathway) and nia1nia2 (NR pathway) were more resistant to Al, with lower root Al content, higher xyloglucan content, and more Al accumulation in the root cell walls. By contrast, the xxt5 mutant with reduced xyloglucan content exhibited an Al-sensitive phenotype. Interestingly, Al treatment increased the endogenous auxin and NO levels, and the auxin levels induced under Al stress further stimulated NO production. Auxin application reduced Al retention in hemicellulose and decreased the xyloglucan content, similar to the effects observed with GSNO. In yucca and aux1-7 mutants, exogenous application of NO resulted in responses similar to those of the WT, whereas exogenous auxin had little effect on the noa1 mutant under Al stress. In addition, as auxin had similar effects on the nia1nia2 mutant and the WT, exogenous auxin and NO had little effect on the xxt5 mutant under Al stress, further confirming that auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al.


Asunto(s)
Arabidopsis , Glucanos , Óxido Nítrico , Xilanos , Arabidopsis/genética , Aluminio/farmacología , Pared Celular , Ácidos Indolacéticos
15.
Appl Environ Microbiol ; 90(1): e0130023, 2024 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-38112424

RESUMEN

Streptomyces bingchenggensis is an industrial producer of milbemycins, which are important anthelmintic and insecticidal agents. Two-component systems (TCSs), which are typically situated in the same operon and are composed of a histidine kinase and a response regulator, are the predominant signal transduction pathways involved in the regulation of secondary metabolism in Streptomyces. Here, an atypical TCS, AtcR/AtcK, in which the encoding genes (sbi_06838/sbi_06839) are organized in a head-to-head pair, was demonstrated to be indispensable for the biosynthesis of multiple secondary metabolites in S. bingchenggensis. With the null TCS mutants, the production of milbemycin and yellow compound was abolished but nanchangmycin was overproduced. Transcriptional analysis and electrophoretic mobility shift assays showed that AtcR regulated the biosynthesis of these three secondary metabolites by a MilR3-mediated cascade. First, AtcR was activated by phosphorylation from signal-triggered AtcK. Second, the activated AtcR promoted the transcription of milR3. Third, MilR3 specifically activated the transcription of downstream genes from milbemycin and yellow compound biosynthetic gene clusters (BGCs) and nanR4 from the nanchangmycin BGC. Finally, because NanR4 is a specific repressor in the nanchangmycin BGC, activation of MilR3 downstream genes led to the production of yellow compound and milbemycin but inhibited nanchangmycin production. By rewiring the regulatory cascade, two strains were obtained, the yield of nanchangmycin was improved by 45-fold to 6.08 g/L and the production of milbemycin was increased twofold to 1.34 g/L. This work has broadened our knowledge on atypical TCSs and provided practical strategies to engineer strains for the production of secondary metabolites in Streptomyces.IMPORTANCEStreptomyces bingchenggensis is an important industrial strain that produces milbemycins. Two-component systems (TCSs), which consist of a histidine kinase and a response regulator, are the predominant signal transduction pathways involved in the regulation of secondary metabolism in Streptomyces. Coupled encoding genes of TCSs are typically situated in the same operon. Here, TCSs with encoding genes situated in separate head-to-head neighbor operons were labeled atypical TCSs. It was found that the atypical TCS AtcR/AtcK played an indispensable role in the biosynthesis of milbemycin, yellow compound, and nanchangmycin in S. bingchenggensis. This atypical TCS regulated the biosynthesis of specialized metabolites in a cascade mediated via a cluster-situated regulator, MilR3. Through rewiring the regulatory pathways, strains were successfully engineered to overproduce milbemycin and nanchangmycin. To the best of our knowledge, this is the first report on atypical TCS, in which the encoding genes of RR and HK were situated in separate head-to-head neighbor operons, involved in secondary metabolism. In addition, data mining showed that atypical TCSs were widely distributed in actinobacteria.


Asunto(s)
Éteres , Macrólidos , Compuestos de Espiro , Streptomyces , Histidina Quinasa/metabolismo , Streptomyces/genética , Proteínas Bacterianas/genética
16.
J Med Virol ; 96(2): e29403, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38293806

RESUMEN

Stimulatorof interferon genes (STING) is an intracellular sensor of cyclic dinucleotides involved in the innate immune response against pathogen- or self-derived DNA. For years, interferon (IFN) induction of cyclic GMP-AMP synthase (cGAS)-STING has been considered as a canonical pattern defending the host from viral invasion. The mechanism of the cGAS-STING-IFN pathway has been well-illustrated. However, other signalling cascades driven by cGAS-STING have emerged in recent years and some of them have been found to possess antiviral ability independent of IFN. Here, we summarize the current progress on cGAS-STING-mediated nonclassic antiviral activities with an emphasis on the nuclear factor-κB and autophagy pathways, which are the most-studied pathways. In addition, we briefly present the primordial function of the cGAS-STING pathway in primitive species to show the importance of IFN-unrelated antiviral activity from an evolutionary angle. Finally, we discuss open questions that need to be solved for further exploitation of this field.


Asunto(s)
Inmunidad Innata , Nucleotidiltransferasas , Humanos , Nucleotidiltransferasas/genética , Transducción de Señal , Interferones , Antivirales/farmacología
17.
J Exp Bot ; 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-39126211

RESUMEN

The endoplasmic reticulum (ER) is crucial for maintaining cell homeostasis because it is the primary site for synthesizing secreted and transmembrane proteins and lipids. The unfolded protein response (UPR) is activated to restore ER homeostasis under ER stress. However, the relationship between lipids and the ER stress response in plants is not well understood. Arabidopsis Golgi anti-apoptotic proteins (GAAPs) are involved in resisting ER stress. To elucidate the function of GAAPs, PASTICCINO2 (PAS2), involved in very long-chain fatty acid (VLCFA) synthesis, was found to interact with GAAPs and IRE1. Single pas2 and gaap1/gaap2pas2 double mutants exhibited increased seedling damage and impaired UPR response under chronic ER stress. Site mutation combined with genetic analysis revealed that the role of PAS2 in resisting ER stress depended on its VLCFA synthesis domain. VLCFA contents were upregulated under ER stress, which required GAAPs. Exogenous VLCFAs partially restored the defect in UPR upregulation caused by PAS2 or GAAP mutations under chronic ER stress. These findings demonstrate that the association of PAS2 with GAAPs confers plant resistance to ER stress by regulating VLCFA synthesis and the UPR. This provides a basis for further studies on the connection between lipids and cell fate decisions under stress.

18.
J Biomed Sci ; 31(1): 70, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-39003473

RESUMEN

Coronaviruses employ various strategies for survival, among which the activation of endogenous or exogenous apoptosis stands out, with viral proteins playing a pivotal role. Notably, highly pathogenic coronaviruses such as SARS-CoV-2, SARS-CoV, and MERS-CoV exhibit a greater array of non-structural proteins compared to low-pathogenic strains, facilitating their ability to induce apoptosis via multiple pathways. Moreover, these viral proteins are adept at dampening host immune responses, thereby bolstering viral replication and persistence. This review delves into the intricate interplay between highly pathogenic coronaviruses and apoptosis, systematically elucidating the molecular mechanisms underpinning apoptosis induction by viral proteins. Furthermore, it explores the potential therapeutic avenues stemming from apoptosis inhibition as antiviral agents and the utilization of apoptosis-inducing viral proteins as therapeutic modalities. These insights not only shed light on viral pathogenesis but also offer novel perspectives for cancer therapy.


Asunto(s)
Apoptosis , SARS-CoV-2 , Humanos , SARS-CoV-2/fisiología , Proteínas Virales/metabolismo , Proteínas Virales/genética , Coronavirus del Síndrome Respiratorio de Oriente Medio/fisiología , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/fisiología , COVID-19/virología
19.
Neurochem Res ; 49(8): 2197-2214, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38834846

RESUMEN

Neuroinflammation and endothelial cell apoptosis are prominent features of blood-brain barrier (BBB) disruption, which have been described in Alzheimer's disease (AD) and can predict cognitive decline. Recent reports revealed vascular ß-amyloid (Aß) deposits, Muller cell degeneration and microglial dysfunction in the retina of AD patients. However, there has been no in-depth research on the roles of inflammation, retinal endothelial cell apoptosis, and blood-retinal barrier (BRB) damage in AD retinopathy. We found that Raddeanin A (RDA) could improve pathological and cognitive deficits in a mouse model of Alzheimer's disease by targeting ß-amyloidosis, However, the effects of RDA on AD retinal function require further study. To clarify whether RDA inhibits inflammation and apoptosis and thus improves BRB function in AD-related retinopathy. In vitro we used Aß-treated HRECs and MIO-M1 cells, and in vivo we used 3×Tg-AD mice to investigate the effect of RDA on BRB in AD-related retinopathy. We found that RDA could improve BRB function in AD-related retinopathy by inhibiting NLRP3-mediated inflammation and suppressing Wnt/ß-catenin pathway-mediated apoptosis, which is expected to improve the pathological changes in AD-related retinopathy and the quality of life of AD patients.


Asunto(s)
Enfermedad de Alzheimer , Apoptosis , Barrera Hematorretinal , Ratones Transgénicos , Retina , Animales , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Apoptosis/efectos de los fármacos , Barrera Hematorretinal/efectos de los fármacos , Barrera Hematorretinal/metabolismo , Retina/efectos de los fármacos , Retina/metabolismo , Retina/patología , Ratones , Inflamación/metabolismo , Inflamación/tratamiento farmacológico , Ratones Endogámicos C57BL , Humanos , Péptidos beta-Amiloides/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Vía de Señalización Wnt/efectos de los fármacos , Vía de Señalización Wnt/fisiología , Masculino
20.
Langmuir ; 40(17): 9144-9154, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38629776

RESUMEN

Wastewater pollutants are a major threat to natural resources, with antibiotics and heavy metals being common water contaminants. By harnessing clean, renewable solar energy, photocatalysis facilitates the synergistic removal of heavy metals and antibiotics. In this paper, MXene was both a template and raw material, and MXene-derived oxide (TiO2) and SnIn4S8 Z-scheme composite materials were synthesized and characterized. The synergistic mode of photocatalytic reduction and oxidation leads to the enhanced utilization of e-/h+ pairs. The TiO2/SnIn4S8 exhibited a higher photocatalytic capacity for the simultaneous removal of tetracycline (TC) (20 mg·L-1) and Cr(VI) (15 mg·L-1). The main active substances of TC degradation and Cr(VI) reduction were identified via free radical scavengers and electron paramagnetic resonance (EPR). Additionally, the potential photocatalytic degradation route of TC was thoroughly elucidated through liquid chromatography-mass spectrometry (LC-MS).

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA