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1.
Immunity ; 57(1): 1-3, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38198847

RESUMEN

TREM2 is exclusively expressed by microglia in the brain and is strongly associated with Alzheimer's disease risk. In this issue of Immunity, Tagliatti et al. shed light on a novel role of TREM2 in shaping neuronal bioenergetics during development.


Asunto(s)
Microglía , Neuronas , Encéfalo
2.
Immunity ; 56(8): 1794-1808.e8, 2023 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-37442133

RESUMEN

Triggering receptor expressed on myeloid cells 2 (TREM2) is strongly linked to Alzheimer's disease (AD) risk, but its functions are not fully understood. Here, we found that TREM2 specifically attenuated the activation of classical complement cascade via high-affinity binding to its initiator C1q. In the human AD brains, the formation of TREM2-C1q complexes was detected, and the increased density of the complexes was associated with lower deposition of C3 but higher amounts of synaptic proteins. In mice expressing mutant human tau, Trem2 haploinsufficiency increased complement-mediated microglial engulfment of synapses and accelerated synaptic loss. Administration of a 41-amino-acid TREM2 peptide, which we identified to be responsible for TREM2 binding to C1q, rescued synaptic impairments in AD mouse models. We thus demonstrate a critical role for microglial TREM2 in restricting complement-mediated synaptic elimination during neurodegeneration, providing mechanistic insights into the protective roles of TREM2 against AD pathogenesis.


Asunto(s)
Enfermedad de Alzheimer , Complemento C1q , Ratones , Animales , Humanos , Complemento C1q/genética , Complemento C1q/metabolismo , Encéfalo/metabolismo , Sinapsis/metabolismo , Activación de Complemento , Microglía/metabolismo , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo
3.
Mol Cell ; 73(2): 250-263.e5, 2019 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-30527662

RESUMEN

Metazoan chromosomes are sequentially partitioned into topologically associating domains (TADs) and then into smaller sub-domains. One class of sub-domains, insulated neighborhoods, are proposed to spatially sequester and insulate the enclosed genes through self-association and chromatin looping. However, it has not been determined functionally whether promoter-enhancer interactions and gene regulation are broadly restricted to within these loops. Here, we employed published datasets from murine embryonic stem cells (mESCs) to identify insulated neighborhoods that confine promoter-enhancer interactions and demarcate gene regulatory regions. To directly address the functionality of these regions, we depleted estrogen-related receptor ß (Esrrb), which binds the Mediator co-activator complex, to impair enhancers of genes within 222 insulated neighborhoods without causing mESC differentiation. Esrrb depletion reduces Mediator binding, promoter-enhancer looping, and expression of both nascent RNA and mRNA within the insulated neighborhoods without significantly affecting the flanking genes. Our data indicate that insulated neighborhoods represent functional regulons in mammalian genomes.


Asunto(s)
Cromosomas de los Mamíferos , Elementos de Facilitación Genéticos , Elementos Aisladores , Células Madre Embrionarias de Ratones/fisiología , Regiones Promotoras Genéticas , Transcripción Genética , Animales , Sitios de Unión , Factor de Unión a CCCTC/genética , Factor de Unión a CCCTC/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Bases de Datos Genéticas , Regulación hacia Abajo , Ratones , Unión Proteica , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Receptores de Estrógenos/genética , Receptores de Estrógenos/metabolismo , Cohesinas
4.
Brain Behav Immun ; 113: 275-288, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37482204

RESUMEN

Over the past decade, compelling genetic evidence has highlighted the crucial role of microglial dysregulation in the development of Alzheimer's disease (AD). As resident immune cells in the brain, microglia undergo dystrophy and senescence during the chronic progression of AD. To explore the potential therapeutic benefits of replenishing the brain with new microglia in AD, we utilized the CSF1R inhibitor PLX3397 to deplete existing microglia and induce repopulation after inhibitor withdrawal in 5xFAD transgenic mice. Our findings revealed the remarkable benefits of microglial repopulation in ameliorating AD-associated cognitive deficits, accompanied by a notable elevation in synaptic proteins and an enhancement of hippocampal long-term potentiation (LTP). Additionally, we observed the profound restoration of microglial morphology and synaptic engulfment following their self-renewal. The impact of microglial repopulation on amyloid pathology is dependent on the duration of repopulation. Transcriptome analysis revealed a high resemblance between the gene expression profiles of repopulated microglia from 5xFAD mice and those of microglia from WT mice. Importantly, the dysregulated neurotrophic signaling pathway and hippocampal neurogenesis in the AD brain are restored following microglial replenishment. Lastly, we demonstrated that the repopulation restores the expression of brain-derived neurotrophic factor (BDNF) in microglia, thereby contributing to synaptic plasticity. In conclusion, our findings provide compelling evidence to support the notion that microglial self-renewal confers substantial benefits to the AD brain by restoring the BDNF neurotrophic signaling pathway. Thus, targeted microglial repopulation emerges as a highly promising and novel therapeutic strategy for alleviating cognitive impairment in AD.


Asunto(s)
Enfermedad de Alzheimer , Ratones , Animales , Enfermedad de Alzheimer/metabolismo , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Microglía/metabolismo , Ratones Transgénicos , Transducción de Señal , Cognición , Modelos Animales de Enfermedad
5.
Thromb J ; 21(1): 29, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36922808

RESUMEN

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare disease characterized by generalized gastrointestinal polyps, ectodermal abnormalities and variable gastrointestinal symptoms. Few cases to date have described complications with deep vein thrombosis (DVT). Here we reported a rare case of CCS concomitant with DVT. The patient's clinical details, endoscopic findings, safety, and efficacy are reported. CASE PRESENTATION: A 58-year-old patient was admitted to our hospital with recurrent diarrhea, overall abnormal appearance, including hyperpigmentation, hair loss and onychodystrophy, and multiple polyps distributed along the gastrointestinal tract except the esophagus. After considerable assessment, the patient was diagnosed with CCS. She was also diagnosed with concurrent DVT, nephrotic syndrome, and infectious enteritis during the course of disease. After treatment with a combination of methylprednisolone, mesalazine, antibiotics, rivaroxaban, and nutritional support during the 24 months of following the patient in this case, the clinical manifestations and endoscopic findings reached complete remission two years after the diagnosis. CONCLUSION: To our knowledge, this study is the first case of CCS complicated with DVT reported in China. Although rare, it is important to consider that DVT may occur after CCS and that it is vital to conduct careful follow-up.

6.
Arch Gynecol Obstet ; 306(3): 893-900, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35635620

RESUMEN

PURPOSE: Hysterosalpingo-contrast sonography (HyCoSy) is the preferred method for evaluating fallopian tubal patency, and it is associated with improved rates of natural pregnancy among infertile patients. However, the mechanism underlying the improvement in pregnancy rates following HyCoSy remains unclear. This study aimed to investigate the effect of HyCoSy examination on endometrial receptivity as well as pregnancy rates among infertile women. METHODS: This prospective study included 120 women with unexplained infertility who visited our department between June 2018 and February 2021. These patients were classified into the study group (n = 60) and the control group (n = 60) depending on their willingness to undergo three-dimensional HyCoSy in the present cycle (study group) or 6 months later (control group). Endometrial characteristics, including endometrial thickness and pattern as well as the endometrial blood flow distribution pattern, were measured twice by transvaginal Doppler ultrasonography in the preovulatory phase before and after HyCoSy examination. Participants were followed for 6 months to observe the outcome of spontaneous conception. RESULTS: Compared with the control group, the study group had a significantly higher cumulative pregnancy rate at 6 months after HyCoSy (21.6% [13/60] vs 5.0% [3/60], P = 0.007). More patients in the study group showed improved endometrial blood flow distribution (P = 0.021, χ2 = 7.699), but no differences in endometrial thickness and pattern were observed between the groups (P > 0.05). CONCLUSION: HyCoSy examination may improve endometrial perfusion and has a therapeutic effect on improving spontaneous pregnancy among women with unexplained infertility.


Asunto(s)
Pruebas de Obstrucción de las Trompas Uterinas , Infertilidad Femenina , Medios de Contraste , Pruebas de Obstrucción de las Trompas Uterinas/métodos , Trompas Uterinas/diagnóstico por imagen , Femenino , Humanos , Histerosalpingografía/métodos , Imagenología Tridimensional/métodos , Infertilidad Femenina/diagnóstico , Estudios Prospectivos , Ultrasonografía/métodos
7.
J Neuroinflammation ; 18(1): 286, 2021 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-34893068

RESUMEN

BACKGROUND: TREM2 is a microglial receptor genetically linked to the risk for Alzheimer's disease (AD). The cerebrospinal fluid (CSF) levels of soluble TREM2 (sTREM2) have emerged as a valuable biomarker for the disease progression in AD and higher CSF levels of sTREM2 are linked to slower cognitive decline. Increasing sTREM2 in mouse models of amyloidosis reduces amyloid-related pathology through modulating microglial functions, suggesting a beneficial role of sTREM2 in microglia biology and AD pathology. METHODS: In the current study, we performed serial C- and N-terminal truncations of sTREM2 protein to define the minimal sequence requirement for sTREM2 function. We initially assessed the impacts of sTREM2 mutants on microglial functions by measuring cell viability and inflammatory responses. The binding of the sTREM2 mutants to oligomeric Aß was determined by solid-phase protein binding assay and dot blot assay. We further evaluated the impacts of sTREM2 mutants on amyloid-related pathology by direct stereotaxic injection of sTREM2 proteins into the brain of 5xFAD mice. RESULTS: We found that both sTREM2 fragments 41-81 and 51-81 enhance cell viability and inflammatory responses in primary microglia. However, the fragment 51-81 exhibited impaired affinity to oligomeric Aß. When administrated to the 5xFAD mice brain, the sTREM2 fragment 41-81, but not 51-81, increased the number of plaque-associated microglia and reduced the plaque deposition. Interestingly, the fragment 41-81 was more efficient than the physiological form of sTREM2 in ameliorating Aß-related pathology. CONCLUSIONS: Our results indicate that the interaction of sTREM2 truncated variants with Aß is essential for enhancing microglial recruitment to the vicinity of an amyloid plaque and reducing the plaque load. Importantly, we identified a 41-amino acid sequence of sTREM2 that is sufficient for modulating microglial functions and more potent than the full-length sTREM2 in reducing the plaque load and the plaque-associated neurotoxicity. Taken together, our data provide more insights into the mechanisms underlying sTREM2 function and the minimal active sTREM2 sequence represents a promising candidate for AD therapy.


Asunto(s)
Amiloidosis/genética , Amiloidosis/patología , Encéfalo/patología , Glicoproteínas de Membrana/genética , Microglía/patología , Fenotipo , Receptores Inmunológicos/genética , Secuencia de Aminoácidos , Animales , Células Cultivadas , Células HEK293 , Humanos , Ratones
8.
J Neurosci ; 37(7): 1772-1784, 2017 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-28077724

RESUMEN

Triggering Receptor Expressed on Myeloid cells 2 (TREM2), which is expressed on myeloid cells including microglia in the CNS, has recently been identified as a risk factor for Alzheimer's disease (AD). TREM2 transmits intracellular signals through its transmembrane binding partner DNAX-activating protein 12 (DAP12). Homozygous mutations inactivating TREM2 or DAP12 lead to Nasu-Hakola disease; however, how AD risk-conferring variants increase AD risk is not clear. To elucidate the signaling pathways underlying reduced TREM2 expression or loss of function in microglia, we respectively knocked down and knocked out the expression of TREM2 in in vitro and in vivo models. We found that TREM2 deficiency reduced the viability and proliferation of primary microglia, reduced microgliosis in Trem2-/- mouse brains, induced cell cycle arrest at the G1/S checkpoint, and decreased the stability of ß-catenin, a key component of the canonical Wnt signaling pathway responsible for maintaining many biological processes, including cell survival. TREM2 stabilized ß-catenin by inhibiting its degradation via the Akt/GSK3ß signaling pathway. More importantly, treatment with Wnt3a, LiCl, or TDZD-8, which activates the ß-catenin-mediated Wnt signaling pathway, rescued microglia survival and microgliosis in Trem2-/- microglia and/or in Trem2-/- mouse brain. Together, our studies demonstrate a critical role of TREM2-mediated Wnt/ß-catenin pathway in microglial viability and suggest that modulating this pathway therapeutically may help to combat the impaired microglial survival and microgliosis associated with AD.SIGNIFICANCE STATEMENT Mutations in the TREM2 (Triggering Receptor Expressed on Myeloid cells 2) gene are associated with increased risk for Alzheimer's disease (AD) with effective sizes comparable to that of the apolipoprotein E (APOE) ε4 allele, making it imperative to understand the molecular pathway(s) underlying TREM2 function in microglia. Our findings shed new light on the relationship between TREM2/DNAX-activating protein 12 (DAP12) signaling and Wnt/ß-catenin signaling and provide clues as to how reduced TREM2 function might impair microglial survival in AD pathogenesis. We demonstrate that TREM2 promotes microglial survival by activating the Wnt/ß-catenin signaling pathway and that it is possible to restore Wnt/ß-catenin signaling when TREM2 activity is disrupted or reduced. Therefore, we demonstrate the potential for manipulating the TREM2/ß-catenin signaling pathway for the treatment of AD.


Asunto(s)
Glicoproteínas de Membrana/metabolismo , Microglía/metabolismo , Receptores Inmunológicos/metabolismo , Vía de Señalización Wnt/fisiología , beta Catenina/metabolismo , Adyuvantes Inmunológicos/farmacología , Animales , Animales Recién Nacidos , Encéfalo/citología , Caspasa 3/metabolismo , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Células Cultivadas , Ciclina D1/genética , Ciclina D1/metabolismo , Inhibidores Enzimáticos/farmacología , Agonistas de Aminoácidos Excitadores/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Ácido Kaínico/farmacología , Cloruro de Litio/farmacología , Masculino , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos C57BL , Microglía/efectos de los fármacos , Proteolisis/efectos de los fármacos , Receptores Inmunológicos/genética , Tiadiazoles/farmacología , Vía de Señalización Wnt/efectos de los fármacos
9.
Zhongguo Zhong Yao Za Zhi ; 43(2): 216-221, 2018 Jan.
Artículo en Zh | MEDLINE | ID: mdl-29552835

RESUMEN

The common Aconitum herbs in clinical application mainly include Aconiti Radix(Chuanwu), Aconiti Kusnezoffii Radix(Caowu) and Aconiti Lateralis Radix Praeparaia(Fuzi), all of which have toxicity. Therefore, the safety of using Chinese patent drugs including Aconitum herbs has become an hot topic in clinical controversy. Based on the data-mining methods, this study explored the characteristics and causes of adverse drug reactions/events (ADR/ADE) of the Chinese patent drugs including Aconitum, in order to provide pharmacovigilance and rational drug use suggestions for clinical application. The detailed ADR/ADE reports about the Chinese patent drugs including Aconitum herbs were retrieved in the domestic literature databases since 1984 to now. The information extraction and data-mining were conducted based on the platforms of Microsoft office Excel 2016, Clementine 12.0 and Cytoscape 3.3.0. Finally, 78 detailed ADR/ADE reports involving a total of 30 varieties were included. 92.31% ADR/ADE were surely or likely led by the Chinese patent drugs including Aconitum, mostly involving multiple system/organ damages with good prognosis, and even 1 case of death. The incidence of included ADRs/ADEs was associated with various factors such as the patient idiosyncratic, drug toxicity, as well as clinical medication. The patient age was most closely related to ADR/ADEs, and those aged from 60 to 69 were more easily suffered from the ADRs/ADEs of Chinese patent drugs including Aconitum. The probability of ADR/ADEs for the drugs including Chuanwu or Caowu was greater than that of Fuzi, and the using beyond the instructions dose was the most important potential safety hazard in the clinical medication process. For the regular and characteristics of ADR/ADEs led by Chinese patent drugs including Aconitum, special attention shall be paid to the elder patients or with the patients with allergies; strictly control the dosage and course of treatment, strengthen the safety medication education to public, and avoid misuse or abuse to ensure rational drug use.


Asunto(s)
Aconitum/efectos adversos , Medicamentos Herbarios Chinos/efectos adversos , Minería de Datos , Bases de Datos Bibliográficas , Humanos , Medicamentos sin Prescripción/efectos adversos
10.
J Biol Chem ; 290(25): 15866-15877, 2015 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-25957402

RESUMEN

Triggering receptor expressed on myeloid cells 2 (TREM2) is a DAP12-associated receptor expressed in microglia, macrophages, and other myeloid-derived cells. Previous studies have suggested that TREM2/DAP12 signaling pathway reduces inflammatory responses and promotes phagocytosis of apoptotic neurons. Recently, TREM2 has been identified as a risk gene for Alzheimer disease (AD). Here, we show that DAP12 stabilizes the C-terminal fragment of TREM2 (TREM2-CTF), a substrate for γ-secretase. Co-expression of DAP12 with TREM2 selectively increased the level of TREM2-CTF with little effects on that of full-length TREM2. The interaction between DAP12 and TREM2 is essential for TREM2-CTF stabilization as a mutant form of DAP12 with disrupted interaction with TREM2 failed to exhibit such an effect. Silencing of either Trem2 or Dap12 gene significantly exacerbated pro-inflammatory responses induced by lipopolysaccharides (LPS). Importantly, overexpression of either full-length TREM2 or TREM2-CTF reduced LPS-induced inflammatory responses. Taken together, our results support a role of DAP12 in stabilizing TREM2-CTF, thereby protecting against excessive pro-inflammatory responses.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Lipopolisacáridos/toxicidad , Glicoproteínas de Membrana/metabolismo , Proteínas de la Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Secretasas de la Proteína Precursora del Amiloide/genética , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Células HEK293 , Humanos , Inflamación/inducido químicamente , Inflamación/genética , Inflamación/metabolismo , Inflamación/patología , Glicoproteínas de Membrana/genética , Proteínas de la Membrana/genética , Ratones , Mutación , Estabilidad Proteica/efectos de los fármacos , Estructura Terciaria de Proteína , Receptores Inmunológicos/genética
11.
J Biol Chem ; 290(43): 26043-50, 2015 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-26374899

RESUMEN

Several heterozygous missense mutations in the triggering receptor expressed on myeloid cells 2 (TREM2) have recently been linked to risk for a number of neurological disorders including Alzheimer disease (AD), Parkinson disease, and frontotemporal dementia. These discoveries have re-ignited interest in the role of neuroinflammation in the pathogenesis of neurodegenerative diseases. TREM2 is highly expressed in microglia, the resident immune cells of the central nervous system. Along with its adaptor protein, DAP12, TREM2 regulates inflammatory cytokine release and phagocytosis of apoptotic neurons. Here, we report apolipoprotein E (apoE) as a novel ligand for TREM2. Using a biochemical assay, we demonstrated high-affinity binding of apoE to human TREM2. The functional significance of this binding was highlighted by increased phagocytosis of apoE-bound apoptotic N2a cells by primary microglia in a manner that depends on TREM2 expression. Moreover, when the AD-associated TREM2-R47H mutant was used in biochemical assays, apoE binding was vastly reduced. Our data demonstrate that apoE-TREM2 interaction in microglia plays critical roles in modulating phagocytosis of apoE-bound apoptotic neurons and establish a critical link between two proteins whose genes are strongly linked to the risk for AD.


Asunto(s)
Apolipoproteínas E/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Enfermedad de Alzheimer/metabolismo , Animales , Apoptosis , Células HEK293 , Humanos , Ligandos , Glicoproteínas de Membrana/genética , Ratones , Ratones Noqueados , Neuronas/metabolismo , Fagocitosis , Unión Proteica , Receptores Inmunológicos/genética
12.
J Neuroinflammation ; 13(1): 304, 2016 12 08.
Artículo en Inglés | MEDLINE | ID: mdl-27931217

RESUMEN

BACKGROUND: Neuroinflammation is characterized by microglial activation and the increased levels of cytokines and chemokines in the central nervous system (CNS). Recent evidence has implicated both beneficial and toxic roles of microglia when over-activated upon nerve injury or in neurodegenerative diseases, including Alzheimer's disease (AD). The low-density lipoprotein receptor-related protein 1 (LRP1) is a major receptor for apolipoprotein E (apoE) and amyloid-ß (Aß), which play critical roles in AD pathogenesis. LRP1 regulates inflammatory responses in peripheral tissues by modulating the release of inflammatory cytokines and phagocytosis. However, the roles of LRP1 in brain innate immunity and neuroinflammation remain unclear. METHODS: In this study, we determined whether LRP1 modulates microglial activation by knocking down Lrp1 in mouse primary microglia. LRP1-related functions in microglia were also assessed in the presence of LRP1 antagonist, the receptor-associated protein (RAP). The effects on the production of inflammatory cytokines were measured by quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Potential involvement of specific signaling pathways in LRP1-regulated functions including mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) were assessed using specific inhibitors. RESULTS: We found that knocking down of Lrp1 in mouse primary microglia led to the activation of both c-Jun N-terminal kinase (JNK) and NF-κB pathways with corresponding enhanced sensitivity to lipopolysaccharide (LPS) in the production of pro-inflammatory cytokines. Similar effects were observed when microglia were treated with LRP1 antagonist RAP. In addition, treatment with pro-inflammatory stimuli suppressed Lrp1 expression in microglia. Interestingly, NF-κB inhibitor not only suppressed the production of cytokines induced by the knockdown of Lrp1 but also restored the down-regulated expression of Lrp1 by LPS. CONCLUSIONS: Our study uncovers that LRP1 suppresses microglial activation by modulating JNK and NF-κB signaling pathways. Given that dysregulation of LRP1 has been associated with AD pathogenesis, our work reveals a critical regulatory mechanism of microglial activation by LRP1 that could be associated with other AD-related pathways thus further nominating LRP1 as a potential disease-modifying target for the treatment of AD.


Asunto(s)
MAP Quinasa Quinasa 4/metabolismo , Microglía/inmunología , FN-kappa B/metabolismo , Receptores de LDL/metabolismo , Transducción de Señal/fisiología , Proteínas Supresoras de Tumor/metabolismo , Péptidos beta-Amiloides/farmacología , Animales , Animales Recién Nacidos , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Proteína Asociada a Proteínas Relacionadas con Receptor de LDL/farmacología , Lipopolisacáridos/farmacología , Proteína 1 Relacionada con Receptor de Lipoproteína de Baja Densidad , Ratones , Ratones Endogámicos C57BL , Microglía/efectos de los fármacos , Fragmentos de Péptidos/farmacología , ARN Mensajero/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Receptores de LDL/genética , Transducción de Señal/efectos de los fármacos , Transfección , Proteínas Supresoras de Tumor/genética
13.
iScience ; 27(6): 110006, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38868202

RESUMEN

Apolipoprotein E (apoE) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Microglia exhibit a substantial upregulation of apoE in AD-associated circumstances, despite astrocytes being the primary source of apoE expression and secretion in the brain. Although the role of astrocytic apoE in the brain has been extensively investigated, it remains unclear that whether and how apoE particles generated from astrocytes and microglia differ in biological characteristic and function. Here, we demonstrate the differences in size between apoE particles generated from microglia and astrocytes. Microglial apoE particles impair neurite growth and synapses, and promote neuronal senescence, whereas depletion of GPNMB (glycoprotein non-metastatic melanoma protein B) in microglial apoE particles mitigated these deleterious effects. In addition, human APOE4-expressing microglia are more neurotoxic than APOE3-bearing microglia. For the first time, these results offer concrete evidence that apoE particles produced by microglia are involved in neuronal senescence and toxicity.

14.
mBio ; : e0234623, 2023 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-37874152

RESUMEN

Cerebral malaria (CM) is a severe neurological complication of Plasmodium falciparum infection with acute brain lesions. Genetic variations in both host and parasite have been associated with susceptibility to CM, but the underlying molecular mechanism remains unclear. Here, we demonstrate that variants of human apolipoprotein E (hApoE) impact the outcome of Plasmodium berghei ANKA (PbA)-induced experimental cerebral malaria (ECM). Mice carrying the hApoE2 isoform have fewer intracerebral hemorrhages and are more resistant to ECM than mice bearing the hApoE3, hApoE4, or endogenous murine ApoE (mApoE). hApoE2 mice infected with PbA showed increased splenomegaly and IFN-γ levels in serum but reduced cerebral cell apoptosis that correlated with the survival advantage against ECM. In addition, upregulated expression of genes associated with lipid metabolism and downregulated expression of genes linked to immune responses were observed in the brain tissue of hApoE2 mice relative to ECM-susceptible mice after PbA infection. Notably, serum cholesterol and the cholesterol content of brain-infiltrating CD8+ T cells are significantly higher in infected hApoE2 mice, which might contribute to a significant reduction in the sequestration of brain CD8+ T cells. Consistent with the finding that fewer brain lesions occurred in infected hApoE2 mice, fewer behavioral deficits were observed in the hApoE2 mice. Finally, a meta-analysis of publicly available data also showed an increased hApoE2 allele in the malaria-endemic African population, suggesting malaria selection. This study shows that hApoE2 protects mice from ECM through suppression of CD8+ T cell activation and migration to the brain and enhanced cholesterol metabolism.IMPORTANCECerebral malaria (CM) is the deadliest complication of malaria infection with an estimated 15%-25% mortality. Even with timely and effective treatment with antimalarial drugs such as quinine and artemisinin derivatives, survivors of CM may suffer long-term cognitive and neurological impairment. Here, we show that human apolipoprotein E variant 2 (hApoE2) protects mice from experimental CM (ECM) via suppression of CD8+ T cell activation and infiltration to the brain, enhanced cholesterol metabolism, and increased IFN-γ production, leading to reduced endothelial cell apoptosis, BBB disruption, and ECM symptoms. Our results suggest that hApoE can be an important factor for risk assessment and treatment of CM in humans.

15.
J Sep Sci ; 35(5-6): 625-32, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22517637

RESUMEN

High shear technique coupled with high-performance counter-current chromatography was successfully used for the extraction and online isolation of seven highly polar chemical constituents from the Brassica napus L. The lower phase of ethyl acetate-n-butanol-water (1:4:5, v:v:v) was used as both the high shear technique solvent and high-performance counter-current chromatography mobile phase. Seven compounds of 14.2 mg of uridine, 4.6 mg of xanthosine, 7.8 mg of guanosine, 5.3 mg of adenosine, 19.5 mg of kaempferol-3,4'-di-O-ß-D-glucopyranoside, 17.7 mg of kaempferol-3-O-(2-O-ß-D-glucopyranosy1)-ß-D-glucopyranoside, and 25.7 mg of an unknown compound, with a high-performance liquid chromatography (HPLC) purity over 95.0%, were obtained in a one-step extraction-separation process within 130 min from 20.0 g of raw material of pollen of Brassica napus L. Moreover, the mode of elution-extrusion was employed for the separation of the last one compound. The isolated compounds were analyzed by HPLC, and the chemical structures of the compounds mentioned above were identified by UV and NMR. It is the first time to combine the high shear technique and high-performance counter-current chromatography for the online isolation of the nature products.


Asunto(s)
Brassica napus/química , Fraccionamiento Químico/métodos , Cromatografía Líquida de Alta Presión/métodos , Distribución en Contracorriente/métodos , Extractos Vegetales/aislamiento & purificación , Polen/química , Automatización , Extractos Vegetales/análisis
16.
PLoS Genet ; 5(6): e1000535, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19557187

RESUMEN

Telomeres are nucleoprotein structures located at the linear ends of eukaryotic chromosomes. Telomere integrity is required for cell proliferation and survival. Although the vast majority of eukaryotic species use telomerase as a primary means for telomere maintenance, a few species can use recombination or retrotransposon-mediated maintenance pathways. Since Saccharomyces cerevisiae can use both telomerase and recombination to replicate telomeres, budding yeast provides a useful system with which to examine the evolutionary advantages of telomerase and recombination in preserving an organism or cell under natural selection. In this study, we examined the life span in telomerase-null, post-senescent type II survivors that have employed homologous recombination to replicate their telomeres. Type II recombination survivors stably maintained chromosomal integrity but exhibited a significantly reduced replicative life span. Normal patterns of cell morphology at the end of a replicative life span and aging-dependent sterility were observed in telomerase-null type II survivors, suggesting the type II survivors aged prematurely in a manner that is phenotypically consistent with that of wild-type senescent cells. The shortened life span of type II survivors was extended by calorie restriction or TOR1 deletion, but not by Fob1p inactivation or Sir2p over-expression. Intriguingly, rDNA recombination was decreased in type II survivors, indicating that the premature aging of type II survivors was not caused by an increase in extra-chromosomal rDNA circle accumulation. Reintroduction of telomerase activity immediately restored the replicative life span of type II survivors despite their heterogeneous telomeres. These results suggest that telomere recombination accelerates cellular aging in telomerase-null type II survivors and that telomerase is likely a superior telomere maintenance pathway in sustaining yeast replicative life span.


Asunto(s)
Recombinación Genética , Saccharomyces cerevisiae/fisiología , Telómero/genética , Senescencia Celular , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Telómero/fisiología
17.
World J Gastroenterol ; 28(34): 4993-5006, 2022 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-36160648

RESUMEN

BACKGROUND: Oxidized low-density lipoprotein (ox-LDL), which is abnormally increased in the serum of colorectal cancer (CRC) patients consuming a high-fat diet (HFD), may be one of the risk factors for the development of CRC. Ox-LDL exerts a regulatory effect on macrophages and may influence CRC through the tumor microenvironment. The role of ox-LDL in CRC remains unclear. AIM: To investigate the role of ox-LDL through macrophages in HFD associated CRC. METHODS: The expression of ox-LDL and CD206 was detected in colorectal tissues of CRC patients with hyperlipidemia and HFD-fed mice by immunofluorescence. We stimulated the macrophages with 20 µg/mL ox-LDL and assessed the expression levels of CD206 and the cytokines by cell fluorescence and quantitative polymerase chain reaction. We further knocked down LOX-1, the surface receptor of ox-LDL, to confirm the function of ox-LDL in macrophages. Then, LoVo cells were co-cultured with the stimulated macrophages to analyze the CD44 and CD133 expression by western blot. RESULTS: The expression of ox-LDL and the CD206 was significantly increased in the stroma of colorectal tissues of CRC patients with hyperlipidemia, and also upregulated in the HFD-fed mice. Moreover, an increased level of CD206 and decreased level of inducible nitric oxide synthase were observed in macrophages after ox-LDL continuous stimulation. Such effects were inhibited when the surface receptor LOX-1 was knocked down in macrophages. Ox-LDL could induce CD206+ macrophages, which resulted in high expression of CD44 and CD133 in co-cultured LoVo cells. CONCLUSION: Ox-LDL stimulates CD206+ macrophages to upregulate CD44 and CD133 expression in HFD related CRC.


Asunto(s)
Neoplasias Colorrectales , Hiperlipidemias , Antígeno AC133 , Animales , Neoplasias Colorrectales/metabolismo , Citocinas/metabolismo , Dieta Alta en Grasa/efectos adversos , Receptores de Hialuranos , Lipoproteínas LDL , Macrófagos/metabolismo , Receptor de Manosa , Ratones , Óxido Nítrico Sintasa de Tipo II/metabolismo , Receptores Depuradores de Clase E/genética , Receptores Depuradores de Clase E/metabolismo , Microambiente Tumoral
18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(2): 547-50, 2011 Feb.
Artículo en Zh | MEDLINE | ID: mdl-21510424

RESUMEN

A quantitative determination method of the total flavonoids in Olea europaea L. leaves using rutin as a standard substance was developed. Two coloration systems including Al(NO3)3-NaNO2-NaOH and AlCl3 were both used. The latter was selected as the optimal determination method by comparing with the results. The main interference of the matrix was discussed. The result showed that the AlCl3 coloration method is simple, accurate and reproducible with good linear relationship, and it can be looked as a reference method for the determination of total flavonoids in herbal materials or natural products.


Asunto(s)
Flavonoides/análisis , Olea/química , Espectrofotometría Ultravioleta/métodos , Compuestos de Aluminio , Hojas de la Planta/química
19.
World J Clin Cases ; 9(29): 8894-8900, 2021 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-34734072

RESUMEN

BACKGROUND: Ovarian pregnancy after assisted reproductive technology treatment has rarely been reported; ovarian pregnancy following intrauterine insemination (IUI) is even rarer, and only nine cases have previously been reported. CASE SUMMARY: We report a case of ovarian pregnancy rupture after ovulation induction and IUI. The patient presented with bilateral lower abdominal pain and was referred to the emergency department. Ultrasound examination revealed ovarian pregnancy and intraperitoneal bleeding. Laparoscopy revealed an ovarian pregnancy with hemoperitoneum, which was subsequently removed. Pelvic adhesions were detected intraoperatively, which were treated immediately. The patient spontaneously conceived an intrauterine pregnancy 3 mo later, which was ongoing at the time of writing this study. CONCLUSION: Close attention should be paid to any history of pelvic inflammatory disease before commencing IUI treatment,and patients with such a history should be closely followed up after IUI. Early measurement of serum ß-human chorionic gonadotropin levels and ultrasonic examination are essential for timely diagnosis of ovarian pregnancy after ovulation induction and IUI to avoid more serious complications.

20.
Transl Pediatr ; 9(6): 802-808, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33457302

RESUMEN

BACKGROUND: One-lung ventilation (OLV) in infants is a commonly used airway technique during thoracic surgery. Current research has primarily focused on the operation of the airways and the occurrence of complications. However, there has been minimal data on the pulmonary gas exchange in infants before and after OLV. This study aimed to assess the efficacy of bronchial blockers (BBs) on the pulmonary gas exchange in infants with OLV. METHODS: A total of 22 infants requiring OLV from January 2017 to August 2019 were included in this study. OLV was achieved by placing BBs outside the endotracheal tube, and all surgeries were performed by the same experienced anesthesiologist. Numerous clinical features, including the oxygenation index (OI), alveolar-arterial oxygen tension gradient (PA-aO2), pulmonary dynamic compliance (Cdyn), OLV time, pulmonary collapse time, degree of pulmonary collapse at the operative side, operative time, and immediate hemodynamic indexes before and after intubation were assessed. Data from the arterial blood gases and the ventilator's parameters were obtained at three time points: 15 minutes before OLV (pre-OLV), 15 minutes after the initiation of OLV (during OLV), and 15 minutes after the termination of OLV (post-OLV). RESULTS: For all patients, the pulmonary gas exchange during OLV was significantly different from both pre-OLV and post-OLV. However, no significant changes of pulmonary function were observed before and after OLV. Extended OLV time was associated with decreased OI and Cdyn, and increased PA-aO2 gradient (P<0.001). In addition, no significant changes of hemodynamic indexes before and after intubation were detected. The degree of lung collapse on the operational side during OLV was optimal. CONCLUSIONS: In this study, the efficacy of BBs on the pulmonary gas exchange in infants with OLV was assessed. The results suggested that although each parameter of pulmonary function pre-OLV were similar to those of post-OLV, an extended period of OLV may lead to compromised lung function.

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