RESUMO
Highly penetrant autosomal dominant Alzheimer's disease (ADAD) comprises a distinct disease entity as compared to the far more prevalent form of AD in which common variants collectively contribute to risk. The downstream pathways that distinguish these AD forms in specific cell types have not been deeply explored. We compared single-nucleus transcriptomes among a set of 27 cases divided among PSEN1-E280A ADAD carriers, sporadic AD, and controls. Autophagy genes and chaperones clearly defined the PSEN1-E280A cases compared to sporadic AD. Spatial transcriptomics validated the activation of chaperone-mediated autophagy genes in PSEN1-E280A. The PSEN1-E280A case in which much of the brain was spared neurofibrillary pathology and harbored a homozygous APOE3-Christchurch variant revealed possible explanations for protection from AD pathology including overexpression of LRP1 in astrocytes, increased expression of FKBP1B, and decreased PSEN1 expression in neurons. The unique cellular responses in ADAD and sporadic AD require consideration when designing clinical trials.
Assuntos
Doença de Alzheimer , Presenilina-1 , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Humanos , Presenilina-1/genética , Masculino , Feminino , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Análise de Sequência de RNA/métodos , Autofagia/genética , Transcriptoma , Idoso , Neurônios/metabolismo , Neurônios/patologia , Pessoa de Meia-Idade , Astrócitos/metabolismo , Astrócitos/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação a Tacrolimo/genética , Idoso de 80 Anos ou mais , Análise de Célula ÚnicaRESUMO
Alzheimer's disease (AD) is an irreversible and neurodegenerative disorder. Its etiology is not clear, but the involvement of genetic components plays a central role in the onset of the disease. In the present study, the expression of 10 genes (APP, PS1 and PS2, APOE, APBA2, LRP1, GRIN2B, INSR, GJB1, and IDE) involved in the main pathways related to AD were analyzed in auditory cortices and cerebellum from 29 AD patients and 29 healthy older adults. Raw analysis revealed tissue-specific changes in genes LRP1, INSR, and APP. A correlation analysis showed a significant effect also tissue-specific AD in APP, GRIN2B, INSR, and LRP1. Furthermore, the E4 allele of the APOE gene revealed a significant correlation with change expression tissue-specific in ABPA2, APP, GRIN2B, LRP1, and INSR genes. To assess the existence of a correction between changes in target gene expression and a probability of AD in each tissue (auditory cortices and cerebellum) an analysis of the effect of expressions was realized and showed that the reduction in the expression of the APP in auditory cortex and GRIN2B cerebellum had a significant effect in increasing the probability of AD, in the same logic, our result also suggesting that increased expression of the LRP1 and INSR genes had a significant effect on increasing the probability of AD. Our results showed tissue-specific gene expression alterations associated with AD and certainly opened new perspectives to characterize factors involved in gene regulation and to obtain possible biomarkers for AD.
Assuntos
Doença de Alzheimer , Antígenos CD , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Masculino , Feminino , Idoso , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Cerebelo/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Córtex Auditivo/metabolismo , Precursor de Proteína beta-Amiloide/genética , Idoso de 80 Anos ou mais , Apolipoproteínas E/genética , Expressão Gênica/genética , Estudos de Casos e ControlesRESUMO
Oropouche orthobunyavirus (OROV; Peribunyaviridae) is a mosquito-transmitted virus that causes widespread human febrile illness in South America, with occasional progression to neurologic effects. Host factors mediating the cellular entry of OROV are undefined. Here, we show that OROV uses the host protein low-density lipoprotein-related protein 1 (Lrp1) for efficient cellular infection. Cells from evolutionarily distinct species lacking Lrp1 were less permissive to OROV infection than cells with Lrp1. Treatment of cells with either the high-affinity Lrp1 ligand receptor-associated protein (RAP) or recombinant ectodomain truncations of Lrp1 significantly reduced OROV infection. In addition, chimeric vesicular stomatitis virus (VSV) expressing OROV glycoproteins (VSV-OROV) bound to the Lrp1 ectodomain in vitro. Furthermore, we demonstrate the biological relevance of the OROV-Lrp1 interaction in a proof-of-concept mouse study in which treatment of mice with RAP at the time of infection reduced tissue viral load and promoted survival from an otherwise lethal infection. These results with OROV, along with the recent finding of Lrp1 as an entry factor for Rift Valley fever virus, highlight the broader significance of Lrp1 in cellular infection by diverse bunyaviruses. Shared strategies for entry, such as the critical function of Lrp1 defined here, provide a foundation for the development of pan-bunyaviral therapeutics.
Assuntos
Infecções por Bunyaviridae , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Orthobunyavirus , Internalização do Vírus , Animais , Infecções por Bunyaviridae/metabolismo , Infecções por Bunyaviridae/virologia , Técnicas de Inativação de Genes , Humanos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos , Orthobunyavirus/fisiologia , América do SulRESUMO
Activated alpha-2 Macroglobulin (α2M*) is specifically recognized by the cluster I/II of LRP1 (Low-density lipoprotein Receptor-related Protein-1). LRP1 is a scaffold protein for insulin receptor involved in the insulin-induced glucose transporter type 4 (GLUT4) translocation to plasma membrane and glucose uptake in different types of cells. Moreover, the cluster II of LRP1 plays a critical role in the internalization of atherogenic lipoproteins, such as aggregated Low-density Lipoproteins (aggLDL), promoting intracellular cholesteryl ester (CE) accumulation mainly in arterial intima and myocardium. The aggLDL uptake by LRP1 impairs GLUT4 traffic and the insulin response in cardiomyocytes. However, the link between CE accumulation, insulin action, and cardiac dysfunction are largely unknown. Here, we found that α2M* increased GLUT4 expression on cell surface by Rab4, Rab8A, and Rab10-mediated recycling through PI3K/Akt and MAPK/ERK signaling activation. Moreover, α2M* enhanced the insulin response increasing insulin-induced glucose uptake rate in the myocardium under normal conditions. On the other hand, α2M* blocked the intracellular CE accumulation, improved the insulin response and reduced cardiac damage in HL-1 cardiomyocytes exposed to aggLDL. In conclusion, α2M* by its agonist action on LRP1, counteracts the deleterious effects of aggLDL in cardiomyocytes, which may have therapeutic implications in cardiovascular diseases associated with hypercholesterolemia.
Assuntos
Membrana Celular/metabolismo , Insulina/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Macroglobulinas/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Western Blotting , Linhagem Celular , Glucose/metabolismo , Insulina/farmacologia , Lipoproteínas LDL/genética , Lipoproteínas LDL/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Camundongos , Microscopia Confocal , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/fisiologiaRESUMO
Tumor necrosis factor-alpha (TNFα) inhibitors could prevent neurological disorders systemically, but their design generally relies on molecules unable to cross the blood-brain barrier (BBB). This research was aimed to design and characterize a novel TNFα inhibitor based on the angiopeptide-2 as a BBB shuttle molecule fused to the extracellular domain of human TNFα receptor 2 and a mutated vascular endothelial growth factor (VEGF) dimerization domain. This new chimeric protein (MTV) would be able to trigger receptor-mediated transcytosis across the BBB via low-density lipoprotein receptor-related protein-1 (LRP-1) and inhibit the cytotoxic effect of TNFα more efficiently because of its dimeric structure. Stably transformed CHO cells successfully expressed MTV, and its purification by Immobilized-Metal Affinity Chromatography (IMAC) rendered high purity degree. Mutated VEGF domain included in MTV did not show cell proliferation or angiogenic activities measured by scratch and aortic ring assays, which corroborate that the function of this domain is restricted to dimerization. The pairs MTV-TNFα (Kd 279 ± 40.9 nM) and MTV-LRP1 (Kd 399 ± 50.5 nM) showed high affinity by microscale thermophoresis, and a significant increase in cell survival was observed after blocking TNFα with MTV in a cell cytotoxicity assay. Also, the antibody staining in CHOK1 and bEnd3 cells demonstrated the adhesion of MTV to the LRP1 receptor located in the cell membrane. These results provide compelling evidence for the proper functioning of the three main domains of MTV individually, which encourage us to continue the research with this new molecule as a potential candidate for the systemic treatment of neurological disorders.
Assuntos
Anti-Inflamatórios/farmacologia , Endotoxinas/antagonistas & inibidores , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Peptídeos/genética , Receptores Tipo II do Fator de Necrose Tumoral/genética , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/metabolismo , Barreira Hematoencefálica/metabolismo , Células CHO , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetulus , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Endotoxinas/metabolismo , Endotoxinas/toxicidade , Expressão Gênica , Humanos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos , Modelos Biológicos , Modelos Moleculares , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Engenharia de Proteínas/métodos , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/toxicidade , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Physical exercise has profound effects on quality of life and susceptibility to chronic disease; however, the regulation of skeletal muscle function at the molecular level after exercise remains unclear. We tested the hypothesis that the benefits of exercise on muscle function are linked partly to microtraumatic events that result in accumulation of circulating heme. Effective metabolism of heme is controlled by Heme Oxygenase-1 (HO-1, Hmox1), and we find that mouse skeletal muscle-specific HO-1 deletion (Tam-Cre-HSA-Hmox1fl/fl) shifts the proportion of muscle fibers from type IIA to type IIB concomitant with a disruption in mitochondrial content and function. In addition to a significant impairment in running performance and response to exercise training, Tam-Cre-HSA-Hmox1fl/fl mice show remarkable muscle atrophy compared to Hmox1fl/fl controls. Collectively, these data define a role for heme and HO-1 as central regulators in the physiologic response of skeletal muscle to exercise.
Assuntos
Heme Oxigenase-1/genética , Heme/metabolismo , Proteínas de Membrana/genética , Fibras Musculares Esqueléticas/metabolismo , Atrofia Muscular/genética , Condicionamento Físico Animal/fisiologia , 5-Aminolevulinato Sintetase/genética , 5-Aminolevulinato Sintetase/metabolismo , Animais , Ferroquelatase/genética , Ferroquelatase/metabolismo , Regulação da Expressão Gênica , Heme Oxigenase-1/deficiência , Isoenzimas/genética , Isoenzimas/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Masculino , Proteínas de Membrana/deficiência , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Atrofia Muscular/metabolismo , Atrofia Muscular/fisiopatologia , Proteína MyoD/genética , Proteína MyoD/metabolismo , Fator de Transcrição PAX7/genética , Fator de Transcrição PAX7/metabolismo , Transdução de Sinais , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Hemin is an erythropoietic inductor capable of inducing autophagy in erythroid-like cell lines. Low-density lipoprotein receptor-related protein 1 (LRP1) is a transmembrane receptor involved in a wide range of cellular processes, such as proliferation, differentiation, and metabolism. Our aim was to evaluate whether LRP1 is responsible for hemin activity in K562 cells, with the results demonstrating a three-fold increase in LRP1 gene expression levels (P-values <0.001) when assessed by quantitative real-time RT-PCR (qRT-PCR). Moreover, a 70% higher protein amount was observed compared with control condition (P-values <0.01) by Western blot (WB). Time kinetic assays demonstrated a peak in light chain 3 (LC3) II (LC3II) levels after 8 h of hemin stimulation and the localization of LRP1 in the autophagosome structures. Silencing LRP1 by siRNA decreased drastically the hemin-induced autophagy activity by almost 80% compared with control cells (P-values <0.01). Confocal localization and biochemical analysis indicated a significant redistribution of LRP1 from early endosomes and recycling compartments to late endosomes and autophagolysosomes, where the receptor is degraded. We conclude that LRP1 is responsible for hemin-induced autophagy activity in the erythroblastic cell line and that hemin-LRP1 complex activation promotes a self-regulation of the receptor. Our results suggest that hemin, via the LRP1 receptor, favors erythroid maturation by inducing an autophagic response, making it a possible therapeutic candidate to help in the treatment of hematological disorders.
Assuntos
Autofagossomos/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Regulação Leucêmica da Expressão Gênica , Hemina/farmacologia , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Autofagossomos/metabolismo , Autofagia/genética , Células HeLa , Humanos , Células K562 , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/antagonistas & inibidores , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Transporte Proteico/efeitos dos fármacos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de SinaisRESUMO
Metabolic syndrome (MetS) is a highly prevalent disorder which can be used to identify individuals with a higher risk for cardiovascular disease and type 2 diabetes. This metabolic syndrome is characterized by a combination of physiological, metabolic, and molecular alterations such as insulin resistance, dyslipidemia, and central obesity. The low-density lipoprotein receptor-related protein 1 (LRP1A member of the LDL receptor family) is an endocytic and signaling receptor that is expressed in several tissues. It is involved in the clearance of chylomicron remnants from circulation, and has been demonstrated to play a key role in the lipid metabolism at the hepatic level. Recent studies have shown that LRP1 is involved in insulin receptor (IR) trafficking and intracellular signaling activity, which have an impact on the regulation of glucose homeostasis in adipocytes, muscle cells, and brain. In addition, LRP1 has the potential to inhibit or sustain inflammation in macrophages, depending on its cellular expression, as well as the presence of particular types of ligands in the extracellular microenvironment. In this review, we summarize existing perspectives and the latest innovations concerning the role of tissue-specific LRP1 in lipoprotein and glucose metabolism, and examine its ability to mediate inflammatory processes related to MetS and atherosclerosis.
Assuntos
Aterosclerose/metabolismo , Glucose/metabolismo , Metabolismo dos Lipídeos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Síndrome Metabólica/metabolismo , Animais , Homeostase , Humanos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genéticaRESUMO
Distinct modes of cell migration contribute to diverse types of cell movements. The mesenchymal mode is characterized by a multistep cycle of membrane protrusion, the formation of focal adhesion, and the stabilization at the leading edge associated with the degradation of extracellular matrix (ECM) components and with regulated extracellular proteolysis. Both α2 -Macroglobulin (α2 M) and its receptor, low density lipoprotein receptor-related protein 1 (LRP1), play important roles in inflammatory processes, by controlling the extracellular activity of several proteases. The binding of the active form of α2 M (α2 M*) to LRP1 can also activate different signaling pathways in macrophages, thus inducing extracellular matrix metalloproteinase-9 (MMP-9) activation and cellular proliferation. In the present study, we investigated whether the α2 M*/LRP1 interaction induces cellular migration of the macrophage-derived cell line, Raw264.7. By using the wound-scratch migration assay and confocal microscopy, we demonstrate that α2 M* induces LRP1-mediated mesenchymal cellular migration. This migration exhibits the production of enlarged cellular protrusions, MT1-MMP distribution to these leading edge protrusions, actin polymerization, focal adhesion formation, and increased intracellular LRP1/ß1-integrin colocalization. Moreover, the presence of calphostin-C blocked the α2 M*-stimulated cellular protrusions, suggesting that the PKC activation is involved in the cellular motility of Raw264.7 cells. These findings could constitute a therapeutic target for inflammatory processes with deleterious consequences for human health, such as rheumatoid arthritis, atherosclerosis and cancer. J. Cell. Biochem. 118: 1810-1818, 2017. © 2016 Wiley Periodicals, Inc.
Assuntos
Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , alfa-Macroglobulinas/farmacologia , Animais , Movimento Celular/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Matriz Extracelular/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Microscopia Confocal , Naftalenos/farmacologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacosRESUMO
The objective of this study was to assess the associations of presenilin 1 (PS1) 1/2, angiotensin I-converting enzyme (ACE) insertion/deletion (I/D), and low-density lipoprotein receptor-related protein (LRP) C/T polymorphisms with the risk of Alzheimer's disease (AD) in the Chinese population. PS1 1/2, ACE I/D, and LRP C/T, which are commonly investigated polymorphisms, were evaluated to obtain summary estimates regarding their associations with AD. In total, the data from 24 studies (2611 patients with AD and 2822 control subjects from 23 provinces and special districts in China) that were obtained from the Chinese Biomedicine Database, China National Knowledge Infrastructure, PubMed, and Medline were included. Different models (i.e., dominant, recessive, etc.) of these polymorphisms were analyzed using the Cochrane Review Manager. Statistically significant associations among patients with AD for the 1/1 genotype of the PS1 1/2 polymorphism [odds ratio (OR) = 1.77, 95% confidence interval (CI) = 1.03-3.04; P = 0.04] and the I/I genotype of the ACE I/D polymorphism (OR = 2.44, 95%CI = 1.78-3.35; P < 0.01) were identified. Statistically significant associations were also found for the PS1 1/2 polymorphism in both the dominant and recessive genetic models, whereas no association was found for the LRP C/T polymorphism. All studies exhibited heterogeneity (P < 0.05). This meta-analysis suggests that the 1/1 genotype of the PS1 1/2 polymorphism and the I/I genotype of the ACE I/D polymorphism are significantly associated with an increased risk of AD in the Chinese population.