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1.
Plant Physiol ; 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38888990

RESUMEN

Grain size is one of the most important traits determining crop yield. However, the mechanism controlling grain size remains unclear. Here, we confirmed the E3 ligase activity of DECREASED GRAIN SIZE 1 (DGS1) in positive regulation of grain size in rice (Oryza sativa) suggested in a previous study. Rice G-protein subunit gamma 2 (RGG2), which negatively regulates grain size, was identified as an interacting protein of DGS1. Biochemical analysis suggested that DGS1 specifically interacts with canonical Gγ subunits (rice G-protein subunit gamma 1 [RGG1] and rice G-protein subunit gamma 2 [RGG2]) rather than non-canonical Gγ subunits (DENSE AND ERECT PANICLE 1 [DEP1], rice G-protein gamma subunit type C 2 [GCC2], GRAIN SIZE 3 [GS3]). We also identified the necessary domains for interaction between DGS1 and RGG2. As an E3 ligase, DGS1 ubiquitinated and degraded RGG2 via a proteasome pathway in several experiments. DGS1 also ubiquitinated RGG2 by its K140, K145 and S147 residues. Thus, this work identified a substrate of the E3 ligase DGS1 and elucidated the post transcriptional regulatory mechanism of the G-protein signalling pathway in the control of grain size.

2.
EMBO Rep ; 24(9): e55494, 2023 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-37493024

RESUMEN

Human CST (CTC1-STN1-TEN1) is a ssDNA-binding complex that interacts with the replisome to aid in stalled fork rescue. We previously found that CST promotes telomere replication to maintain genomic integrity via G-quadruplex (G4) resolution. However, the detailed mechanism by which CST resolves G4s in vivo and whether additional factors are involved remains unclear. Here, we identify RECQ4 as a novel CST-interacting partner and show that RECQ4 can unwind G4 structures in vitro using a FRET assay. Moreover, G4s accumulate at the telomere after RECQ4 depletion, resulting in telomere dysfunction, including the formation of MTSs, SFEs, and TIFs, suggesting that RECQ4 is crucial for telomere integrity. Furthermore, CST is also required for RECQ4 telomere or chromatin localization in response to G4 stabilizers. RECQ4 is involved in preserving genomic stability by CST and RECQ4 disruption impairs restart of replication forks stalled by G4s. Overall, our findings highlight the essential roles of CST and RECQ4 in resolving G-rich regions, where they collaborate to resolve G4-induced replication deficiencies and maintain genomic homeostasis.


Asunto(s)
Replicación del ADN , G-Cuádruplex , Humanos , Proteínas de Unión a Telómeros/genética , Homeostasis del Telómero , Telómero/metabolismo
3.
Nucleic Acids Res ; 51(10): 4914-4928, 2023 06 09.
Artículo en Inglés | MEDLINE | ID: mdl-37021555

RESUMEN

CST (CTC1-STN1-TEN1) is a telomere associated complex that binds ssDNA and is required for multiple steps in telomere replication, including termination of G-strand extension by telomerase and synthesis of the complementary C-strand. CST contains seven OB-folds which appear to mediate CST function by modulating CST binding to ssDNA and the ability of CST to recruit or engage partner proteins. However, the mechanism whereby CST achieves its various functions remains unclear. To address the mechanism, we generated a series of CTC1 mutants and studied their effect on CST binding to ssDNA and their ability to rescue CST function in CTC1-/- cells. We identified the OB-B domain as a key determinant of telomerase termination but not C-strand synthesis. CTC1-ΔB expression rescued C-strand fill-in, prevented telomeric DNA damage signaling and growth arrest. However, it caused progressive telomere elongation and the accumulation of telomerase at telomeres, indicating an inability to limit telomerase action. The CTC1-ΔB mutation greatly reduced CST-TPP1 interaction but only modestly affected ssDNA binding. OB-B point mutations also weakened TPP1 association, with the deficiency in TPP1 interaction tracking with an inability to limit telomerase action. Overall, our results indicate that CTC1-TPP1 interaction plays a key role in telomerase termination.


Asunto(s)
Telomerasa , Humanos , Línea Celular , ADN de Cadena Simple/genética , Mutación , Telomerasa/genética , Telomerasa/metabolismo , Telómero/genética , Telómero/metabolismo , Homeostasis del Telómero , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismo
4.
Plant Cell Physiol ; 65(2): 243-258, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-37955399

RESUMEN

Carbonic anhydrase (CA) catalyzes the reversible CO2 hydration reaction that produces bicarbonate for phosphoenolpyruvate carboxylase (PEPC). This is the initial step for transmitting the CO2 signal in C4 photosynthesis. However, it remains unknown whether the maize (Zea mays L.) CA gene, ZmCA4, plays a role in the maize photosynthesis process. In our study, we found that ZmCA4 was relatively highly expressed in leaves and localized in the chloroplast and the plasma membrane of mesophyll protoplasts. Knock-out of ZmCA4 reduced CA activity, while overexpression of ZmCA4 increased rubisco activity, as well as the quantum yield and relative electron transport rate in photosystem II. Overexpression of ZmCA4 enhanced maize yield-related traits. Moreover, ZmCA4 interacted with aquaporin ZmPIP2;6 in bimolecular fluorescence complementation and co-immunoprecipitation experiments. The double-knock-out mutant for ZmPIP2;6 and ZmCA4 genes showed reductions in its growth, CA and PEPC activities, assimilation rate and photosystem activity. RNA-Seq analysis revealed that the expression of other ZmCAs, ZmPIPs, as well as CO2 signaling pathway homologous genes, and photosynthetic-related genes was all altered in the double-knock-out mutant compared with the wild type. Altogether, our study's findings point to a critical role of ZmCA4 in determining photosynthetic capacity and modulating CO2 signaling regulation via its interaction with ZmPIP2;6, thus providing insight into the potential genetic value of ZmCA4 for maize yield improvement.


Asunto(s)
Acuaporinas , Anhidrasas Carbónicas , Zea mays/metabolismo , Dióxido de Carbono/metabolismo , Anhidrasas Carbónicas/genética , Anhidrasas Carbónicas/metabolismo , Fotosíntesis/genética , Acuaporinas/genética , Acuaporinas/metabolismo , Transducción de Señal/genética , Expresión Génica
5.
Mol Med ; 30(1): 4, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38172666

RESUMEN

BACKGROUND: Autophagic defects are involved in Methamphetamine (Meth)-induced neurotoxicity. Syntaxin 17 (Stx17), a member of the SNARE protein family, participating in several stages of autophagy, including autophagosome-late endosome/lysosome fusion. However, the role of Stx17 and potential mechanisms in autophagic defects induced by Meth remain poorly understood. METHODS: To address the mechanism of Meth-induced cognitive impairment, the adenovirus (AV) and adeno-associated virus (AAV) were injected into the hippocampus for stereotaxis to overexpress Stx17 in vivo to examine the cognitive ability via morris water maze and novel object recognition. In molecular level, the synaptic injury and autophagic defects were evaluated. To address the Meth induced neuronal damage, the epidermal growth factor receptor (EGFR) degradation assay was performed to evaluate the degradability of the "cargos" mediated by Meth, and mechanistically, the maturation of the vesicles, including autophagosomes and endosomes, were validated by the Co-IP and the GTP-agarose affinity isolation assays. RESULTS: Overexpression of Stx17 in the hippocampus markedly rescued the Meth-induced cognitive impairment and synaptic loss. For endosomes, Meth exposure upregulated Rab5 expression and its guanine-nucleotide exchange factor (GEF) (immature endosome), with a commensurate decreased active form of Rab7 (Rab7-GTP) and impeded the binding of Rab7 to CCZ1 (mature endosome); for autophagosomes, Meth treatment elicited a dramatic reduction in the overlap between Stx17 and autophagosomes but increased the colocalization of ATG5 and autophagosomes (immature autophagosomes). After Stx17 overexpression, the Rab7-GTP levels in purified late endosomes were substantially increased in parallel with the elevated mature autophagosomes, facilitating cargo (Aß42, p-tau, and EGFR) degradation in the vesicles, which finally ameliorated Meth-induced synaptic loss and memory deficits in mice. CONCLUSION: Stx17 decrease mediated by Meth contributes to vesicle fusion defects which may ascribe to the immature autophagosomes and endosomes, leading to autophagic dysfunction and finalizes neuronal damage and cognitive impairments. Therefore, targeting Stx17 may be a novel therapeutic strategy for Meth-induced neuronal injury.


Asunto(s)
Autofagosomas , Autofagia , Animales , Ratones , Autofagosomas/metabolismo , Endosomas/metabolismo , Receptores ErbB/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismo , Guanosina Trifosfato/metabolismo
6.
Small ; 20(26): e2310238, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38267815

RESUMEN

Cesium lead halide (CsPbX3, X = Br, Cl, and I) nanocrystals (NCs) are widely concerned and applied in many fields due to the excellent photoelectric performance. However, the toxicity of Pb and the loss of luminescence in water limit its application in vivo. A stable perovskite nanomaterial with good bioimaging properties is developed by incorporating europium (Eu) in CsPbX3 NCs followed with the surface coating of silica (SiO2) shell (CsPbX3:Eu@SiO2). Through the surface coating of SiO2, the luminescence stability of CsPbBr3 in water is improved and the leakage of Pb2+ is significantly reduced. In particular, Eu doping inhibits the photoluminescence quantum yield reduction of CsPbBr3 caused by SiO2 coating, and further reduces the release of Pb2+. CsPbBr3:Eu@SiO2 nanoparticles (NPs) show efficient luminescence in water and good biocompatibility to achieve cell imaging. More importantly, CsPb(ClBr)3:Eu@SiO2 NPs are obtained by adjusting the halogen components, and green light and blue light are realized in zebrafish imaging, showing good imaging effect and biosafety. The work provides a strategy for advanced perovskite nanomaterials toward biological practical application.


Asunto(s)
Cesio , Europio , Plomo , Luminiscencia , Nanopartículas , Dióxido de Silicio , Agua , Pez Cebra , Animales , Dióxido de Silicio/química , Europio/química , Nanopartículas/química , Plomo/química , Cesio/química , Agua/química , Titanio/química , Óxidos , Compuestos de Calcio
7.
Neurochem Res ; 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38884889

RESUMEN

Prompt reperfusion after cerebral ischemia is important to maintain neuronal survival and reduce permanent disability and death. However, the resupply of blood can induce oxidative stress, inflammatory response and apoptosis, further leading to tissue damage. Here, we report the versatile biological roles of transcript-induced in spermiogenesis 40 (Tisp40) in ischemic stroke. We found that the expression of Tisp40 was upregulated in ischemia/reperfusion-induced brain tissues and oxygen glucose deprivation/returned -stimulated neurons. Tisp40 deficiency increased the infarct size and neurological deficit score, and promoted inflammation and apoptosis. Tisp40 overexpression played the opposite role. In vitro, the oxygen glucose deprivation/returned model was established in Tisp40 knockdown and overexpression primary cultured cortical neurons. Tisp40 knockdown can aggravate the process of inflammation and apoptosis, and Tisp40 overexpression ameliorated the aforementioned processes. Mechanistically, Tisp40 protected against ischemic stroke via activating the AKT signaling pathway. Tisp40 may be a new therapeutic target in brain ischemia/reperfusion injury.

8.
Fish Shellfish Immunol ; 144: 109291, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38104702

RESUMEN

Discus fish (Symphysodon aequifasciatus) exhibit a unique parental care behavior: adult discus produces secretion through their skin, on which the larvae live after birth. The immune components in the skin mucus of parental discus would change during different parental care. C-type lectins (CTLs) could identify and eliminate pathogenic microorganisms and play important roles in innate immunity. Studies on CTLs of discus fish especially during parental care, however, are scarce. Here, we identified 186 CTL genes that distributed in 27 linkage groups based on discus genome. Phylogenetic analysis showed that S. aequifasciatus CTL (SaCTL) members were grouped into 14 subfamilies. A total of 80 gene replication events occurred, of which 15 pairs were subjected to segmental duplication and 65 pairs underwent tandem duplication. Ka/Ks ranged from 0.11 (SaCTL25/SaCTL158) to 0.68 (SaCTL36/SaCTL69), all undergoing purifying selection. RNA-seq analysis revealed that SaCTL members, including duplicated genes, in the skin of parental discus show distinct expression patterns in different care stages and between male and female parents. The SaCTL11 was differentially expressed in most care stages and reached the maximum after eggs spawned, but the expression of its paired SaCTL14 was low in each stage. The SaCTL39 increased first and then decreased, reaching a peak in eggs spawned, while paired SaCTL48 first decreased and then increased, reaching a peak in hatched eggs. The SaCTL50 was differentially expressed only in female fish during care, but not in male fish. These results provide new insights into the evolution and potential functional differentiation of CTLs in discus fish during parental care.


Asunto(s)
Cíclidos , Lectinas Tipo C , Femenino , Masculino , Animales , Filogenia , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Cíclidos/genética , Piel/metabolismo , Larva
9.
J Eur Acad Dermatol Venereol ; 38(5): 851-863, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38131517

RESUMEN

BACKGROUND: Psoriasis is an inflammatory skin disease. The pathogenesis of psoriasis has not been fully elucidated. T-lymphokine-activated killer cell-originated protein kinase (TOPK) activity increases in a proinflammatory environment, and inhibiting TOPK blocks inflammation. However, whether TOPK is involved in the pathogenesis of psoriasis remains to be identified. OBJECTIVES: We aimed to study the role of TOPK in psoriasis and attempted to find a drug targeting TOPK for the prevention and treatment of psoriasis. METHOD: Firstly, the expressions of TOPK in psoriatic patients, psoriatic cell and animal model were analysed by Gene Expression Omnibus database, immunohistochemistry (IHC) staining and western blot (WB). After inhibiting TOPK by chemical or gene knockout, the effect of TOPK on the development of psoriasis was verified in cell and animal model by WB, qRT-PCR, ELISA, haematoxylin-eosin (H&E) and IHC staining. Moreover, phosphoproteomic analysis was performed to explore the signalling pathways regulated by TOPK in the occurrence and development of psoriasis. Then, an in vitro kinase assay was performed to prove TOPK kinase activity was inhibited by worenine. Ultimately, WB, qRT-PCR, ELISA, H&E and IHC staining were used to verify the anti-psoriasis effect of worenine by inhibiting TOPK was in cell and animal model. RESULTS: In this study, we found that TOPK was highly expressed in psoriasis patients, psoriatic cell and animal model, which suggests that TOPK might be associated with psoriasis pathogenesis. Interestingly, chemical or genetic inhibition of TOPK alleviated M5- and imiquimod (IMQ)-induced psoriasis-like dermatitis, which further confirmed the role of TOPK in promoting the development of psoriasis. Moreover, we determined that worenine inhibited TOPK kinase activity. In addition, worenine relieved M5- and IMQ-induced psoriasiform dermatitis by inhibiting TOPK activity. CONCLUSIONS: T-lymphokine-activated killer cell-originated protein kinase promotes the development of psoriasis. Therefore, TOPK might be a promising drug target for the prevention and treatment of psoriasis. Worenine alleviates psoriasiform dermatitis by inhibiting TOPK activity, providing new strategies for clinical intervention.


Asunto(s)
Quinasas de Proteína Quinasa Activadas por Mitógenos , Psoriasis , Psoriasis/tratamiento farmacológico , Humanos , Animales , Ratones , Modelos Animales de Enfermedad , Transducción de Señal/efectos de los fármacos
10.
J Lipid Res ; 64(7): 100382, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37116711

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease worldwide, without any Food and Drug Administration-approved pharmacological intervention in clinic. Trim38, as an important member of the TRIM (tripartite motif-containing) family, was largely reported to be involved in the regulation of innate immune and inflammatory responses. However, the functional roles of TRIM38 in NAFLD remain largely unknown. Here, the expression of TRIM38 was first detected in liver samples of both NAFLD mice model and patients diagnosed with NAFLD. We found that TRIM38 expression was downregulated in NAFLD liver tissues compared with normal liver tissues. Genetic Trim38-KO in vivo showed that TRIM38 depletion deteriorated the high-fat diet and high fat and high cholesterol diet-induced hepatic steatosis and high fat and high cholesterol diet-induced liver inflammation and fibrosis. In particular, we found that the effects of hepatocellular lipid accumulation and inflammation induced by palmitic acid and oleic acid were aggravated by TRIM38 depletion but mitigated by TRIM38 overexpression in vitro. Mechanically, RNA-Seq analysis demonstrated that TRIM38 ameliorated nonalcoholic steatohepatitis progression by attenuating the activation of MAPK signaling pathway. We further found that TRIM38 interacted with transforming growth factor-ß-activated kinase 1 binding protein 2 and promoted its protein degradation, thus inhibiting the transforming growth factor-ß-activated kinase 1-MAPK signal cascades. In summary, our study revealed that TRIM38 could suppress hepatic steatosis, inflammatory, and fibrosis in NAFLD via promoting transforming growth factor-ß-activated kinase 1 binding protein 2 degradation. TRIM38 could be a potential target for NAFLD treatment.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Animales , Ratones , Proteínas Portadoras/metabolismo , Colesterol/metabolismo , Dieta Alta en Grasa/efectos adversos , Hígado/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Transducción de Señal , Proteínas de Motivos Tripartitos/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo
11.
J Biol Chem ; 298(12): 102695, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36375638

RESUMEN

Human NAD-dependent isocitrate dehydrogenase or IDH3 (HsIDH3) catalyzes the decarboxylation of isocitrate into α-ketoglutarate in the tricarboxylic acid cycle. It consists of three types of subunits (α, ß, and γ) and exists and functions as the (αßαγ)2 heterooctamer. HsIDH3 is regulated allosterically and/or competitively by numerous metabolites including CIT, ADP, ATP, and NADH. Our previous studies have revealed the molecular basis for the activity and regulation of the αß and αγ heterodimers. However, the molecular mechanism for the allosteric activation of the HsIDH3 holoenzyme remains elusive. In this work, we report the crystal structures of the αß and αγ heterodimers and the (αßαγ)2 heterooctamer containing an α-Q139A mutation in the clasp domain, which renders all the heterodimers and the heterooctamer constitutively active in the absence of activators. Our structural analysis shows that the α-Q139A mutation alters the hydrogen-bonding network at the heterodimer-heterodimer interface in a manner similar to that in the activator-bound αγ heterodimer. This alteration not only stabilizes the active sites of both αQ139Aß and αQ139Aγ heterodimers in active conformations but also induces conformational changes of the pseudo-allosteric site of the αQ139Aß heterodimer enabling it to bind activators. In addition, the αQ139AICT+Ca+NADßNAD structure presents the first pseudo-Michaelis complex of HsIDH3, which allows us to identify the key residues involved in the binding of cofactor, substrate, and metal ion. Our structural and biochemical data together reveal new insights into the molecular mechanisms for allosteric regulation and the catalytic reaction of HsIDH3.


Asunto(s)
Isocitrato Deshidrogenasa , Humanos , Regulación Alostérica , Sitio Alostérico , Catálisis , Dominio Catalítico , Isocitrato Deshidrogenasa/química , Isocitrato Deshidrogenasa/genética , Isocitrato Deshidrogenasa/metabolismo , Cinética , Mutación
12.
J Cell Physiol ; 238(2): 393-406, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36710714

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is a strong stimulant of cardiovascular diseases, affecting one-quarter of the world's population. TBC1 domain family member 25 (TBC1D25) regulates the development of myocardial hypertrophy and cerebral ischemia-reperfusion injury; however, its effect on NAFLD/nonalcoholic steatohepatitis (NASH) has not been reported. In this study, we demonstrated that TBC1D25 expression is upregulated in NASH. TBC1D25 deficiency aggravated hepatic steatosis, inflammation, and fibrosis in NASH. In vitro tests revealed that TBC1D25 overexpression restrained NASH responses. Subsequent mechanistic validation experiments demonstrated that TBC1D25 interfered with NASH progression by inhibiting abnormal lipid accumulation and inflammation. TBC1D25 deficiency significantly promoted NASH occurrence and development. Therefore, TBC1D25 may potentially be used as a clinical therapeutic target for NASH treatment.


Asunto(s)
Hipercolesterolemia , Enfermedad del Hígado Graso no Alcohólico , Hipercolesterolemia/patología , Inflamación/patología , Lípidos , Hígado/metabolismo , Cirrosis Hepática/patología , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Masculino , Animales , Ratones
13.
Plant Biotechnol J ; 21(11): 2358-2373, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37523341

RESUMEN

Tiller and seed number are key determinants of rice (Oryza sativa) yield. These traits are mainly affected by tiller, panicle, spikelet and stigma formation, but to date, no single gene involved in the development of all these organs has been identified. Here, we found a rice mutant defective stigma and panicle (dsp) with greatly reduced numbers of tillers and panicle branches, and ovaries lacking stigmas, due to defects in primordium initiation. We cloned DSP using sequencing-based mapping and verified its function with the CRISPR/Cas9 system. DSP encodes a transcription factor containing an APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) domain that recognizes the GCC motif and a transcription-activating domain at the site of 244-314 that contains an angiosperm-related (AR) motif. Mutating the AR motif resulted in the dsp mutant phenotypes, whereas mutating the AP2/ERF domain led to seedling death. DSP directly regulated PINOID (PID) expression to determine the emergence of rice stigmas, and PID overexpression partially rescued the stigma defect in the dsp cr2-8 and dsp mutants. Moreover, DSP indirectly affected LAX PANICLE1 (LAX1) expression to determine tiller primordium formation and synergistically regulated panicle primordium development. Our results indicated that DSP was a key regulator that modulated different genetic pathways to control the initiation of stigma primordia, the axillary meristem formation of tillers and panicle branches, which revealed their molecular mechanisms and cross-networks, laying the vital foundation for rice yield and trait improvement.


Asunto(s)
Oryza , Oryza/metabolismo , Factores de Transcripción/genética , Fenotipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética
14.
Hepatology ; 75(4): 924-938, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34482560

RESUMEN

BACKGROUND AND AIMS: NASH is a complicated disease characterized by hepatocyte steatosis, inflammation infiltration, and liver fibrosis. Accumulating evidence suggests that the innate immunity plays a key role in NASH progression. Here, we aimed to reveal the role of melanoma differentiation-associated gene 5 (MDA5, also known as Ifih1), a conventional innate immune regulator following viral infection, in the progression of NASH and investigate its underlying mechanism. APPROACH AND RESULTS: We first examined the expression of MDA5 and found that MDA5 was markedly down-regulated in the livers with NASH in human individuals and mice models. MDA5 overexpression significantly inhibits the free fatty acid-induced lipid accumulation and inflammation in hepatocyte in vitro, whereas MDA5 knockdown promotes hepatocyte lipotoxicity. Using hepatocyte-specific Mda5 gene knockout and transgenic mice, we found that diet-induced hepatic steatosis, inflammation, and liver fibrosis were markedly exacerbated by Mda5 deficiency but suppressed by Mda5 overexpression. Mechanistically, we found that the activation of apoptosis signal-regulating kinase 1 (ASK1)-mitogen-activated protein kinase pathway was significantly inhibited by MDA5 but enhanced by MDA5 deletion. We further validated that MDA5 directly interacted with ASK1 and suppressed its N-terminal dimerization. Importantly, blockage of ASK1 with adenovirus-expressing dominant negative ASK1 obviously reversed the lipid accumulation and ASK1 pathway activation when Mda5 was knocked out. CONCLUSIONS: These data indicate that MDA5 is an essential suppressor in NASH. The findings support MDA5 as a regulator of ASK1 and a promising therapeutic target for NASH.


Asunto(s)
Melanoma , Enfermedad del Hígado Graso no Alcohólico , Animales , Inflamación/complicaciones , Lípidos/uso terapéutico , Hígado/metabolismo , Cirrosis Hepática/complicaciones , Cirrosis Hepática/genética , Cirrosis Hepática/prevención & control , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Enfermedad del Hígado Graso no Alcohólico/etiología
15.
Hepatology ; 75(6): 1446-1460, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34662438

RESUMEN

BACKGROUND AND AIMS: Ischemia-reperfusion (I/R) injury is an inevitable complication of liver transplantation (LT) and compromises its prognosis. Glycosyltransferases have been recognized as promising targets for disease therapy, but their roles remain open for study in hepatic I/R (HIR) injury. Here, we aim to demonstrate the exact function and molecular mechanism of a glycosyltransferase, N-acetylgalactosaminyltransferase-4 (GALNT4), in HIR injury. APPROACH AND RESULTS: By an RNA-sequencing data-based correlation analysis, we found a close correlation between GALNT4 expression and HIR-related molecular events in a murine model. mRNA and protein expression of GALNT4 were markedly up-regulated upon reperfusion surgery in both clinical samples from subjects who underwent LT and in a mouse model. We found that GALNT4 deficiency significantly exacerbated I/R-induced liver damage, inflammation, and cell death, whereas GALNT4 overexpression led to the opposite phenotypes. Our in-depth mechanistic exploration clarified that GALNT4 directly binds to apoptosis signal-regulating kinase 1 (ASK1) to inhibit its N-terminal dimerization and subsequent phosphorylation, leading to a robust inactivation of downstream c-Jun N-terminal kinase (JNK)/p38 and NF-κB signaling. Intriguingly, the inhibitory capacity of GALNT4 on ASK1 activation is independent of its glycosyltransferase activity. CONCLUSIONS: GALNT4 represents a promising therapeutic target for liver I/R injury and improves liver surgery prognosis by inactivating the ASK1-JNK/p38 signaling pathway.


Asunto(s)
Hígado , MAP Quinasa Quinasa Quinasa 5 , N-Acetilgalactosaminiltransferasas , Daño por Reperfusión , Animales , Apoptosis , Hígado/patología , MAP Quinasa Quinasa Quinasa 5/metabolismo , Ratones , N-Acetilgalactosaminiltransferasas/genética , Multimerización de Proteína , Daño por Reperfusión/genética , Daño por Reperfusión/prevención & control , Polipéptido N-Acetilgalactosaminiltransferasa
16.
Hepatology ; 75(2): 403-418, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34435375

RESUMEN

BACKGROUND AND AIMS: Although the prevalence of NAFLD has risen dramatically to 25% of the adult population worldwide, there are as yet no approved pharmacological interventions for the disease because of uncertainty about the underlying molecular mechanisms. It is known that mitochondrial dysfunction is an important factor in the development of NAFLD. Mitochondrial antiviral signaling protein (MAVS) is a critical signaling adaptor for host defenses against viral infection. However, the role of MAVS in mitochondrial metabolism during NAFLD progression remains largely unknown. APPROACH AND RESULTS: Based on expression analysis, we identified a marked down-regulation of MAVS in hepatocytes during NAFLD progression. By using MAVS global knockout and hepatocyte-specific MAVS knockout mice, we found that MAVS is protective against diet-induced NAFLD. MAVS deficiency induces extensive mitochondrial dysfunction during NAFLD pathogenesis, which was confirmed as impaired mitochondrial respiratory capacity and membrane potential. Metabolomics data also showed the extensive metabolic disorders after MAVS deletion. Mechanistically, MAVS interacts with the N-terminal stretch of voltage-dependent anion channel 2 (VDAC2), which is required for the ability of MAVS to influence mitochondrial function and hepatic steatosis. CONCLUSIONS: In hepatocytes, MAVS plays an important role in protecting against NAFLD by helping to regulate healthy mitochondrial function. These findings provide insights regarding the metabolic importance of conventional immune regulators and support the possibility that targeting MAVS may represent an avenue for treating NAFLD.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Mitocondrias/metabolismo , Enfermedad del Hígado Graso no Alcohólico/fisiopatología , Animales , Células Cultivadas , Progresión de la Enfermedad , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Células Estrelladas Hepáticas , Hepatocitos , Homeostasis , Humanos , Lipogénesis/genética , Masculino , Metabolómica , Ratones , Ratones Noqueados , Mitocondrias/fisiología , Enfermedad del Hígado Graso no Alcohólico/genética , Cultivo Primario de Células , Canal Aniónico 2 Dependiente del Voltaje/genética , Canal Aniónico 2 Dependiente del Voltaje/metabolismo
17.
Hepatology ; 76(3): 612-629, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-34767673

RESUMEN

BACKGROUND AND AIMS: HCC is one of the main types of primary liver cancer, with high morbidity and mortality and poor treatment effect. Tripartite motif-containing protein 11 (TRIM11) has been shown to promote tumor formation in lung cancer, breast cancer, gastric cancer, and so on. However, the specific function and mechanism of TRIM11 in HCC remain open for study. APPROACH AND RESULTS: Through clinical analysis, we found that the expression of TRIM11 was up-regulated in HCC tissues and was associated with high tumor node metastasis (TNM) stages, advanced histological grade, and poor patient survival. Then, by gain- and loss-of-function investigations, we demonstrated that TRIM11 promoted cell proliferation, migration, and invasion in vitro and tumor growth in vivo. Mechanistically, RNA sequencing and mass spectrometry analysis showed that TRIM11 interacted with pleckstrin homology domain leucine-rich repeats protein phosphatase 1 (PHLPP1) and promoted K48-linked ubiquitination degradation of PHLPP1 and thus promoted activation of the protein kinase B (AKT) signaling pathway. Moreover, overexpression of PHLPP1 blocked the promotional effect of TRIM11 on HCC function. CONCLUSIONS: Our study confirmed that TRIM11 plays an oncogenic role in HCC through the PHLPP1/AKT signaling pathway, suggesting that targeting TRIM11 may be a promising target for the treatment of HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinogénesis/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Leucina , Neoplasias Hepáticas/patología , Dominios Homólogos a Pleckstrina , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteína Fosfatasa 1/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas de Motivos Tripartitos/genética , Proteínas de Motivos Tripartitos/metabolismo , Ubiquitina , Ubiquitina-Proteína Ligasas/metabolismo
18.
Pediatr Res ; 93(3): 586-594, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36195633

RESUMEN

BACKGROUND: Sleep in childhood is affected by behavioral, environmental, and parental factors. We propose that these factors were altered during the COVID-19 pandemic. This study investigates sleep habit changes during the pandemic in 528 children 4-12 years old in the US, leveraging data from the Environmental Influences on Child Health Outcomes (ECHO) Program. METHODS: Data collection occurred in July 2019-March 2020 (pre-pandemic) and two pandemic periods: December 2020-April 2021 and May-August 2021. Qualitative interviews were performed in 38 participants. RESULTS: We found no changes in sleep duration, but a shift to later sleep midpoint during the pandemic periods. There was an increase in latency at the first pandemic collection period but no increase in the frequency of bedtime resistance, and a reduced frequency of naps during the pandemic. Qualitative interviews revealed that parents prioritized routines to maintain sleep duration but were more flexible regarding timing. Children from racial/ethnic minoritized communities slept less at night, had later sleep midpoint, and napped more frequently across all collection periods, warranting in-depth investigation to examine and address root causes. CONCLUSIONS: The COVID-19 pandemic significantly impacted children sleep, but parental knowledge of the importance of sleep might have played a significant protective role. IMPACT: During the COVID-19 pandemic, US children changed their sleep habits, going to bed and waking up later, but their sleep duration did not change. Sleep latency was longer. Parental knowledge of sleep importance might have played a protective role. Regardless of data collection periods, children from racial/ethnic minoritized communities slept less and went to bed later. This is one of the first study on this topic in the US, including prospective pre-pandemic qualitative and quantitative data on sleep habits. Our findings highlight the pandemic long-term impact on childhood sleep. Results warrants further investigations on implications for overall childhood health.


Asunto(s)
COVID-19 , Pandemias , Humanos , Niño , Preescolar , Estudios Prospectivos , Sueño , Recolección de Datos
19.
Environ Res ; 236(Pt 2): 116772, 2023 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-37517496

RESUMEN

BACKGROUND: Drinking water is a common source of exposure to inorganic arsenic. In the US, the Safe Drinking Water Act (SDWA) was enacted to protect consumers from exposure to contaminants, including arsenic, in public water systems (PWS). The reproductive effects of preconception and prenatal arsenic exposure in regions with low to moderate arsenic concentrations are not well understood. OBJECTIVES: This study examined associations between preconception and prenatal exposure to arsenic violations in water, measured via residence in a county with an arsenic violation in a regulated PWS during pregnancy, and five birth outcomes: birth weight, gestational age at birth, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). METHODS: Data for arsenic violations in PWS, defined as concentrations exceeding 10 parts per billion, were obtained from the Safe Drinking Water Information System. Participants of the Environmental influences on Child Health Outcomes Cohort Study were matched to arsenic violations by time and location based on residential history data. Multivariable, mixed effects regression models were used to assess the relationship between preconception and prenatal exposure to arsenic violations in drinking water and birth outcomes. RESULTS: Compared to unexposed infants, continuous exposure to arsenic from three months prior to conception through birth was associated with 88.8 g higher mean birth weight (95% CI: 8.2, 169.5), after adjusting for individual-level confounders. No statistically significant associations were observed between any preconception or prenatal violations exposure and gestational age at birth, preterm birth, SGA, or LGA. CONCLUSIONS: Our study did not identify associations between preconception and prenatal arsenic exposure, defined by drinking water exceedances, and adverse birth outcomes. Exposure to arsenic violations in drinking water was associated with higher birth weight. Future studies would benefit from more precise geodata of water system service areas, direct household drinking water measurements, and exposure biomarkers.


Asunto(s)
Arsénico , Agua Potable , Nacimiento Prematuro , Efectos Tardíos de la Exposición Prenatal , Embarazo , Lactante , Niño , Femenino , Humanos , Recién Nacido , Peso al Nacer , Arsénico/toxicidad , Arsénico/análisis , Estudios de Cohortes , Nacimiento Prematuro/inducido químicamente , Nacimiento Prematuro/epidemiología , Agua Potable/análisis , Retardo del Crecimiento Fetal , Exposición Materna/efectos adversos
20.
Biotechnol Appl Biochem ; 70(1): 403-414, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35638476

RESUMEN

Pinene is a commercially important monoterpene that can be prepared using engineered bacterial and yeast species; however, high pinene levels can adversely affect the stability and permeability of microbial membranes leading to significantly reduced growth yields. This study reports that the fluidities and permeabilities of cell membranes of Candida glycerinogenes decrease as pinene levels increase resulting in adverse effects on cell growth. Exposure of cells to pinene results in upregulation of the genes encoding ergosterol and trehalose whose production helps stabilize their cell membranes. Exogenous addition of ergosterol and trehalose to pinene-treated cells also reduces the fluidity and permeability of the cell membrane, whilst also reducing production of intracellular reactive oxygen species. This led to the finding that the biomass of yeast cells cultivated in shake flask systems are improved by exogenous addition of trehalose and ergosterol. Overexpression of genes that encode trehalose and ergosterol produced a recombinant C. glycerinogenes strain that was found to tolerate higher concentrations of  pinene.


Asunto(s)
Ergosterol , Trehalosa , Trehalosa/farmacología , Trehalosa/metabolismo , Ergosterol/metabolismo , Membrana Celular , Pichia/metabolismo
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