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This study evaluates the impact of fertility costs and utility on the third birth intentions among working women with two children in Hainan, China. A cross-sectional survey was conducted in Hainan Island, China in 2021 using an offline survey. Among 1067 working women with two children, only 8.06 % of participants reported having a third-birth intention. After adjustment for potential confounding factors, higher economic cost (odds ratio = 1.89) and lower succession utility (odds ratio = 5.08) were significantly associated with the lack of intention to have a third child. The analysis further demonstrates that family values significantly modulate these economic and utility considerations, highlighting a strong cultural influence on fertility decisions. This finding underscores the necessity for policies that not only mitigate financial burdens but also promote family values supportive of higher fertility. Such measures are essential for creating a cultural and economic environment conducive to higher birth rates.
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Aim: Low professional help-seeking intention (PHSI) hinders effective treatment of mental illness. PHSI among Chinese students is still understudied and under-recognized. This study aimed to evaluate the status of PHSI and its associated risk factors among Chinese medical students. Methods: A cross-sectional survey was conducted in Hainan province, South China, between January 1, 2021, and May 31, 2021. A total of 2182 medical students were recruited and surveyed via an anonymous structured questionnaire. Logistic regression analyses were performed to identify the factors associated with PHSI. Results: Among the 2182 medical students (mean age 21.0 years (SD = 3.70), 61.5% females), those with and without PHSI were 72.0% and 28.0%, and 16.4% with moderate to severe depression. Male students, those with a high level of depression stigma, serious family dysfunction, and heavy dependence on mobile phones were significantly less likely to seek professional mental health help, with odds ratios (ORs) of 1.5, 2.0, 2.1, and 1.7, respectively. Conclusion: A significant proportion of Chinese medical students demonstrate low PHSI, influenced by factors such as gender, depression stigma, family dysfunction, and mobile phone dependence. Future interventions aimed at increasing medical students' PHSI should prioritize reducing depression stigma, mitigating reliance on mobile phone use, and enhancing family function to address these key barriers to seeking professional mental health support.
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Many inherited visual diseases arise from mutations that affect the structure and function of photoreceptor cells. In some cases, the pathology is accompanied by a massive release of extracellular vesicles from affected photoreceptors. In this study, we addressed whether vesicular release is an exclusive response to ongoing pathology or a normal homeostatic phenomenon amplified in disease. We analyzed the ultrastructure of normal photoreceptors from both rod- and cone-dominant mammalian species and found that these cells release microvesicles budding from their inner segment compartment. Inner segment-derived microvesicles vary in their content, with some of them containing the visual pigment rhodopsin and others appearing to be interconnected with mitochondria. These data suggest the existence of a fundamental process whereby healthy mammalian photoreceptors release mistrafficked or damaged inner segment material as microvesicles into the interphotoreceptor space. This release may be greatly enhanced under pathological conditions associated with defects in protein targeting and trafficking. This article has an associated First Person interview with the first author of the paper.
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Células Fotorreceptoras , Rodopsina , Animales , Humanos , Células Fotorreceptoras/metabolismo , Rodopsina/metabolismo , Transporte de Proteínas , Mamíferos/metabolismoRESUMEN
The combination of chemodynamic therapy (CDT) and chemotherapy is a promising strategy to achieve enhanced anticancer effects. Metal-organic frameworks (MOFs), as multifunctional drug delivery vehicles, have received extensive attention in the biomedical field. Carbohydrate has excellent biocompatibility and targeting ability, which can be used as a targeting ligand due to a specific recognition with glycoprotein receptors that overexpress on cancer cell membranes. Herein, the pH-responsive mannose-modified ferrocene MOFs with rare earth metal were synthesized via coordination-driven self-assembly of 1,1'-Ferrocenedicarboxylic acid and ytterbium chloride. Subsequently, DOX@Fc-MOFs-Mann nanoparticles (NPs) were obtained by loading doxorubicin (DOX) and modifying mannose (Mann), where DOX@Fc-MOFs-Mann NPs were able to precisely target HepG2 cells via mannose receptor and slowly decompose in the acidic environment of tumor to release ferrocene, DOX, and Yb3+. Fe2+ in ferrocene effectively activated Fenton reaction to produce high levels of reactive oxygen species (ROS) for irreversible induction of cell apoptosis or necroptosis. Combined with the chemotherapy (CT) ability of DOX, Yb3+ further induced cell death through its own toxicity to successfully achieved the rare earth metal synergistic CDT and CT combination therapy. This synergistic CDT and CT strategy not only opens up new horizons for rare earth metals in biomedical applications but also provides new inspiration into the construction of glycosyl-modified MOFs.
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Estructuras Metalorgánicas , Metales de Tierras Raras , Nanopartículas , Neoplasias , Línea Celular Tumoral , Doxorrubicina/farmacología , Humanos , Concentración de Iones de Hidrógeno , Manosa , Estructuras Metalorgánicas/farmacología , Estructuras Metalorgánicas/uso terapéutico , Metalocenos/farmacología , Metalocenos/uso terapéutico , Metales de Tierras Raras/farmacología , Metales de Tierras Raras/uso terapéutico , Neoplasias/tratamiento farmacológicoRESUMEN
OBJECTIVE: Stromal interaction molecule 1 (STIM1) is a single-pass transmembrane endoplasmic/sarcoplasmic reticulum (E/SR) protein recognized for its role in a store operated Ca2+ entry (SOCE), an ancient and ubiquitous signaling pathway. Whereas STIM1 is known to be indispensable during development, its biological and metabolic functions in mature muscles remain unclear. METHODS: Conditional and tamoxifen inducible muscle STIM1 knock-out mouse models were coupled with multi-omics tools and comprehensive physiology to understand the role of STIM1 in regulating SOCE, mitochondrial quality and bioenergetics, and whole-body energy homeostasis. RESULTS: This study shows that STIM1 is abundant in adult skeletal muscle, upregulated by exercise, and is present at SR-mitochondria interfaces. Inducible tissue-specific deletion of STIM1 (iSTIM1 KO) in adult muscle led to diminished lean mass, reduced exercise capacity, and perturbed fuel selection in the settings of energetic stress, without affecting whole-body glucose tolerance. Proteomics and phospho-proteomics analyses of iSTIM1 KO muscles revealed molecular signatures of low-grade E/SR stress and broad activation of processes and signaling networks involved in proteostasis. CONCLUSION: These results show that STIM1 regulates cellular and mitochondrial Ca2+ dynamics, energy metabolism and proteostasis in adult skeletal muscles. Furthermore, these findings provide insight into the pathophysiology of muscle diseases linked to disturbances in STIM1-dependent Ca2+ handling.
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Tolerancia al Ejercicio , Proteostasis , Molécula de Interacción Estromal 1 , Animales , Calcio/metabolismo , Metabolismo Energético , Ratones , Músculo Esquelético/metabolismo , Molécula de Interacción Estromal 1/genética , Molécula de Interacción Estromal 1/metabolismoRESUMEN
Chiral macrocycles possess significant value in chiral science and supramolecular chemistry. Pillararenes, as a class of relatively young supramolecular macrocyclic hosts, have been widely used for host-guest recognition and self-assembly. Since the position of substituents on the benzene rings breaks the molecular symmetry (symmetric plane and symmetric center), pillararenes possess planar chirality. However, it is a great challenge to synthesize stable and resolvable enantiomers because of the easy rotation of the phenylene group. In this review, we summarize the construction methods of resolvable chiral pillararenes. We also focus on their applications in enantioselective recognition, chiral switches, chirality sensing, asymmetric catalysis, circularly polarized luminescence, metal-organic frameworks, and highly permeable membranes. Finally, we discuss the future research perspectives in this field of pillararene-based planar chiral materials. We hope that this review will encourage more researchers to work in this exciting field.
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Supramolecular nanostructures (SNSs) have received significant attention in recent years since they endow specific and unique properties to materials. Pillararenes, as a novel group of macrocyclic molecules, present particular features such as ease of modification, more electron-rich cavity as well as captivating host-guest chemistry, thus bestowing them with the abilities to fabricate intriguing SNSs. This feature article highlights the construction methods of pillararene-based supramolecular nanostructures (PSNSs), where most of which are in aqueous media, and the factors that influence the morphological transformation of PSNSs. Moreover, the structure-function relationship of divergent PSNSs is clarified. Finally, the future challenges and perspectives for PSNSs are pointed out and discussed. We hope this review will benefit the researchers interested in engineering PSNSs with on demand morphologies and desired functions.
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Compuestos Macrocíclicos/química , Nanoestructuras/química , Modelos Moleculares , Conformación MolecularRESUMEN
An azine-containing bispillar[5]arene was designed and synthesized by the reaction of aldehyde functionalized-pillar[5]arene and hydrazine. Then, a novel bispillar[5]arene-based supramolecular pseudopolyrotaxane has been successfully prepared via host-guest interaction. Interestingly, by taking advantage of the host-guest interactions, π-π stacking interactions and hydrogen bonding interactions, the multi-stimuli-responsive gel-sol phase transitions of such a supramolecular pseudopolyrotaxane gel were successfully realized under different stimuli, such as acid, temperature, concentration, and competitive guests. Moreover, this supramolecular system could effectively adsorb dye molecule rhodamine B. It is worth noting that this supramolecular pseudopolyrotaxane gel prepared in cyclohexanol solution (BP5·G·C) could be used as an adsorbent material for adsorbing rhodamine B with adsorption efficiency of 98.4%. Meanwhile, the adsorption efficiency was 97.6% for supramolecular pseudopolyrotaxane gel prepared in DMSO-H2O (v : v, 8 : 2) binary solution (BP5·G·D), also indicating the superior adsorption effect of BP5·G·D toward the dye molecule rhodamine B.
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Progressive rod-cone degeneration (PRCD) is a small protein residing in the light-sensitive disc membranes of the photoreceptor outer segment. Until now, the function of PRCD has remained enigmatic despite multiple demonstrations that its mutations cause blindness in humans and dogs. Here, we generated a PRCD knockout mouse and observed a striking defect in disc morphogenesis, whereby newly forming discs do not properly flatten. This leads to the budding of disc-derived vesicles, specifically at the site of disc morphogenesis, which accumulate in the interphotoreceptor matrix. The defect in nascent disc flattening only minimally alters the photoreceptor outer segment architecture beyond the site of new disc formation and does not affect the abundance of outer segment proteins and the photoreceptor's ability to generate responses to light. Interestingly, the retinal pigment epithelium, responsible for normal phagocytosis of shed outer segment material, lacks the capacity to clear the disc-derived vesicles. This deficiency is partially compensated by a unique pattern of microglial migration to the site of disc formation where they actively phagocytize vesicles. However, the microglial response is insufficient to prevent vesicular accumulation and photoreceptors of PRCD knockout mice undergo slow, progressive degeneration. Taken together, these data show that the function of PRCD is to keep evaginating membranes of new discs tightly apposed to each other, which is essential for the high fidelity of photoreceptor disc morphogenesis and photoreceptor survival.
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Proteínas de la Membrana/deficiencia , Morfogénesis/genética , Segmento Externo de las Células Fotorreceptoras Retinianas/patología , Animales , Membrana Celular/metabolismo , Membrana Celular/patología , Micropartículas Derivadas de Células/metabolismo , Micropartículas Derivadas de Células/ultraestructura , Distrofias de Conos y Bastones/genética , Distrofias de Conos y Bastones/patología , Distrofias de Conos y Bastones/veterinaria , Modelos Animales de Enfermedad , Perros , Espacio Extracelular/metabolismo , Proteínas del Ojo/genética , Humanos , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Microscopía Electrónica de Transmisión , Segmento Externo de las Células Fotorreceptoras Retinianas/metabolismo , Segmento Externo de las Células Fotorreceptoras Retinianas/ultraestructura , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/patologíaRESUMEN
One of the strongest susceptibility genes for age-related macular degeneration (AMD) is complement factor H (CFH); however, its impact on AMD pathobiology remains unresolved. Here, the effect of the principal AMD-risk-associated CFH variant (Y402H) on the development and progression of age-dependent AMD-like pathologies was determined in vivo. Transgenic mice expressing equal amounts of the full-length normal human CFH Y402 (CFH-Y/0) or the AMD-risk associated CFH H402 (CFH-H/H) variant on a Cfh-/- background were aged to 90 weeks and switched from normal diet (ND) to a high fat, cholesterol-enriched (HFC) diet for 8 weeks. The resulting phenotype was compared with age-matched controls maintained on ND. Remarkably, an AMD-like phenotype consisting of vision loss, increased retinal pigmented epithelium (RPE) stress, and increased basal laminar deposits was detected only in aged CFH-H/H mice following the HFC diet. These changes were not observed in aged CFH-Y/0 mice or in younger (36- to 40-week-old) CFH mice of both genotypes fed either diet. Biochemical analyses of aged CFH mice after HFC diet revealed genotype-dependent changes in plasma and eyecup lipoproteins, but not complement activation, which correlated with the AMD-like phenotype in old CFH-H/H mice. Specifically, apolipoproteins B48 and A1 are elevated in the RPE/choroid of the aged CFH-H/H mice compared with age-matched control CFH-Y/0 fed a HFC diet. Hence, we demonstrate a functional consequence of the Y402H polymorphism in vivo, which promotes AMD-like pathology development and affects lipoprotein levels in aged mice. These findings support targeting lipoproteins as a viable therapeutic strategy for treating AMD.
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Activación de Complemento/genética , Factor H de Complemento/genética , Lipoproteínas/genética , Degeneración Macular/genética , Animales , Dieta Alta en Grasa/efectos adversos , Femenino , Genotipo , Humanos , Lipoproteínas/metabolismo , Degeneración Macular/patología , Masculino , Ratones , Ratones Transgénicos/genética , Polimorfismo de Nucleótido Simple/genética , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/patologíaRESUMEN
Genetic defects in the synaptic scaffolding protein gene, SHANK2, are linked to a variety of neuropsychiatric disorders, including autism spectrum disorders, schizophrenia, intellectual disability, and bipolar disorder, but the molecular mechanisms underlying the pleotropic effects of SHANK2 mutations are poorly understood. We generated and characterized a line of Shank2 mutant mice by deleting exon 24 (Δe24). Shank2Δe24-/- mice engage in significantly increased locomotor activity, display abnormal reward-seeking behavior, are anhedonic, have perturbations in circadian rhythms, and show deficits in social and cognitive behaviors. While these phenotypes recapitulate the pleotropic behaviors associated with human SHANK2-related disorders, major behavioral features in these mice are reminiscent of bipolar disorder. For instance, their hyperactivity was augmented with amphetamine but was normalized with the mood stabilizers lithium and valproate. Shank2 deficiency limited to the forebrain recapitulated the bipolar mania phenotype. The composition and functions of NMDA and AMPA receptors were altered at Shank2-deficient synapses, hinting toward the mechanism underlying these behavioral abnormalities. Human genetic findings support construct validity, and the behavioral features in Shank2 Δe24 mice support face and predictive validities of this model for bipolar mania. Further genetic studies to understand the contribution of SHANK2 deficiencies in bipolar disorder are warranted.
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Trastorno Bipolar/genética , Actividad Motora/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Anfetamina/farmacología , Anhedonia , Animales , Antimaníacos/uso terapéutico , Conducta Animal , Estimulantes del Sistema Nervioso Central/farmacología , Trastornos Cronobiológicos/tratamiento farmacológico , Trastornos Cronobiológicos/genética , Disfunción Cognitiva/genética , Femenino , Hipocampo/metabolismo , Hipocampo/ultraestructura , Compuestos de Litio/uso terapéutico , Masculino , Ratones , Ratones Noqueados , Actividad Motora/efectos de los fármacos , N-Metilaspartato/metabolismo , Fenotipo , Prosencéfalo/metabolismo , Receptores AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Trastorno de la Conducta Social/genética , Sinapsis/metabolismoRESUMEN
A thioacetohydrazide functionalized pillar[5]arene was synthesized, which could further assemble into a linear supramolecular metal-organic polymer upon adding Zn2+. Furthermore, the obtained linear supramolecular metal-organic polymer could self-assemble to form a fluorescent supramolecular metal-organic gel at high concentration. When TBAOH was added to the viscous solution at high temperature, the obtained solution could not form a supramolecular metal-organic gel upon cooling. More importantly, when Hg2+ ions are added to the metal-organic gel, the strong blue fluorescence is clearly quenched, and this metal-organic gel (xerogel) could effectively remove Hg2+ from water. Simultaneously, a thin film based on the metal-organic gel was prepared, which was confirmed to be a convenient test kit for detecting Hg2+.
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The primary cilium is a highly conserved organelle housing specialized molecules responsible for receiving and processing extracellular signals. A recently discovered property shared across many cilia is the ability to release small vesicles called ectosomes, which are used for exchanging protein and genetic material among cells. In this study, we report a novel role for ciliary ectosomes in building the elaborate photoreceptor outer segment filled with hundreds of tightly packed "disc" membranes. We demonstrate that the photoreceptor cilium has an innate ability to release massive amounts of ectosomes. However, this process is suppressed by the disc-specific protein peripherin, which enables retained ectosomes to be morphed into discs. This new function of peripherin is performed independently from its well-established role in maintaining the high curvature of disc edges, and each function is fulfilled by a separate part of peripherin's molecule. Our findings explain how the outer segment structure evolved from the primary cilium to provide photoreceptor cells with vast membrane surfaces for efficient light capture.
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Micropartículas Derivadas de Células/metabolismo , Cilios/metabolismo , Periferinas/metabolismo , Células Fotorreceptoras/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
p62 is a scaffolding adaptor implicated in the clearance of protein aggregates by autophagy. Reactive oxygen species (ROS) can either stimulate or inhibit NFκB-mediated gene expression influencing cellular fate. We studied the effect of hydrogen peroxide (H2O2)-mediated oxidative stress and NFκB signaling on p62 expression in the retinal pigment epithelium (RPE) and investigated its role in regulation of autophagy and RPE survival against oxidative damage. Cultured human RPE cell line ARPE-19 and primary human adult and fetal RPE cells were exposed to H2O2-induced oxidative stress. The human apolipoprotein E4 targeted-replacement (APOE4) mouse model of AMD was used to study expression of p62 and other autophagy proteins in the retina. p62, NFκB p65 (total, phosphorylated, nuclear and cytoplasmic) and ATG10 expression was assessed by mRNA and protein analyses. Cellular ROS and mitochondrial superoxide were measured by CM-H2DCFDA and MitoSOX staining respectively. Mitochondrial viability was determined using MTT activity. qPCR-array system was used to investigate autophagic genes affected by p62. Nuclear and cytoplasmic levels of NFκB p65 were evaluated after cellular fractionation by Western blotting. We report that p62 is up-regulated in RPE cells under H2O2-induced oxidative stress and promotes autophagic activity. Depletion of endogenous p62 reduces autophagy by downregulation of ATG10 rendering RPE more susceptible to oxidative damage. NFκB p65 phosphorylation at Ser-536 was found to be critical for p62 upregulation in response to oxidative stress. Proteasome inhibition by H2O2 causes p62-NFκB signaling as antioxidant pre-treatment reversed p62 expression and p65 phosphorylation when RPE was challenged by H2O2 but not when by Lactacystin. p62 protein but not RNA levels are elevated in APOE4-HFC AMD mouse model, suggesting reduction of autophagic flux in disease conditions. Our findings suggest that p62 is necessary for RPE cytoprotection under oxidative stress and functions, in part, by modulating ATG10 expression. NFκB p65 activity may be a critical upstream initiator of p62 expression in RPE cells under oxidative stress.
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Autofagia/fisiología , Supervivencia Celular/fisiología , FN-kappa B/fisiología , Estrés Oxidativo/fisiología , Proteínas de Unión al ARN/fisiología , Epitelio Pigmentado de la Retina/fisiología , Proteína Sequestosoma-1/fisiología , Animales , Western Blotting , Línea Celular , Modelos Animales de Enfermedad , Técnica del Anticuerpo Fluorescente , Degeneración Macular/etiología , Degeneración Macular/fisiopatología , Ratones , Fosforilación , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Superóxidos/metabolismo , Regulación hacia ArribaRESUMEN
Peroxisome proliferator-activated receptor-ß/δ (PPARß/δ) is a nuclear receptor that regulates differentiation, inflammation, lipid metabolism, extracellular matrix remodeling, and angiogenesis in multiple tissues. These pathways are also central to the pathogenesis of age-related macular degeneration (AMD), the leading cause of vision loss globally. With the goal of identifying signaling pathways that may be important in the development of AMD, we investigated the impact of PPARß/δ activation on ocular tissues affected in the disease. PPARß/δ is expressed and can be activated in AMD vulnerable cells, including retinal pigment epithelial (RPE) and choroidal endothelial cells. Further, PPARß/δ knockdown modulates AMD-related pathways selectively. Specifically, genetic ablation of Pparß/δ in aged mice resulted in exacerbation of several phenotypic features of early dry AMD, but attenuation of experimentally induced choroidal neovascular (CNV) lesions. Antagonizing PPARß/δ in both in vitro angiogenesis assays and in the in vivo experimentally induced CNV model, inhibited angiogenesis and angiogenic pathways, while ligand activation of PPARß/δ, in vitro, decreased RPE lipid accumulation, characteristic of dry AMD. This study demonstrates for the first time, selective regulation of a nuclear receptor in the eye and establishes that selective targeting of PPARß/δ may be a suitable strategy for treatment of different clinical sub-types of AMD.
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Degeneración Macular/metabolismo , Neovascularización Patológica/metabolismo , PPAR-beta/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Anciano , Animales , Línea Celular , Movimiento Celular/efectos de los fármacos , Movimiento Celular/fisiología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Electrorretinografía , Femenino , Humanos , Macaca mulatta , Degeneración Macular/genética , Masculino , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Neovascularización Patológica/genética , PPAR-beta/agonistas , PPAR-beta/antagonistas & inhibidores , PPAR-beta/genética , Fenotipo , Epitelio Pigmentado de la Retina/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Sulfonas/farmacología , Tiazoles/farmacología , Tiofenos/farmacología , Adulto JovenRESUMEN
Human neuroimaging studies suggest that aberrant neural connectivity underlies behavioural deficits in autism spectrum disorders (ASDs), but the molecular and neural circuit mechanisms underlying ASDs remain elusive. Here, we describe a complete knockout mouse model of the autism-associated Shank3 gene, with a deletion of exons 4-22 (Δe4-22). Both mGluR5-Homer scaffolds and mGluR5-mediated signalling are selectively altered in striatal neurons. These changes are associated with perturbed function at striatal synapses, abnormal brain morphology, aberrant structural connectivity and ASD-like behaviour. In vivo recording reveals that the cortico-striatal-thalamic circuit is tonically hyperactive in mutants, but becomes hypoactive during social behaviour. Manipulation of mGluR5 activity attenuates excessive grooming and instrumental learning differentially, and rescues impaired striatal synaptic plasticity in Δe4-22(-/-) mice. These findings show that deficiency of Shank3 can impair mGluR5-Homer scaffolding, resulting in cortico-striatal circuit abnormalities that underlie deficits in learning and ASD-like behaviours. These data suggest causal links between genetic, molecular, and circuit mechanisms underlying the pathophysiology of ASDs.
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Trastorno del Espectro Autista/fisiopatología , Corteza Cerebral/fisiopatología , Cuerpo Estriado/fisiopatología , Proteínas de Andamiaje Homer/metabolismo , Proteínas del Tejido Nervioso/deficiencia , Receptor del Glutamato Metabotropico 5/metabolismo , Animales , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/patología , Conducta Animal , Corteza Cerebral/patología , Cuerpo Estriado/patología , Femenino , Humanos , Depresión Sináptica a Largo Plazo , Masculino , Ratones , Ratones Noqueados , Proteínas de Microfilamentos , Modelos Neurológicos , Red Nerviosa/patología , Red Nerviosa/fisiopatología , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/fisiología , Eliminación de Secuencia , Conducta SocialRESUMEN
Photoreceptor discs are membrane organelles harboring components of the visual signal transduction pathway. The mechanism by which discs form remains enigmatic and is the subject of a major controversy. Classical studies suggest that discs are formed as serial plasma membrane evaginations, whereas a recent alternative postulates that discs, at least in mammalian rods, are formed through intracellular vesicular fusion. We evaluated these models in mouse rods using methods that distinguish between the intracellular vesicular structures and plasma membrane folds independently of their appearance in electron micrographs. The first differentiated membranes exposed to the extracellular space from intracellular membranes; the second interrogated the orientation of protein molecules in new discs. Both approaches revealed that new discs are plasma membrane evaginations. We further demonstrated that vesiculation and plasma membrane enclosure at the site of new disc formation are artifacts of tissue fixation. These data indicate that all vertebrate photoreceptors use the evolutionary conserved membrane evagination mechanism to build their discs.
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Membrana Celular/metabolismo , Mamíferos/metabolismo , Células Fotorreceptoras Retinianas Bastones/metabolismo , Animales , Transporte Biológico/fisiología , Ratones , Ratones Endogámicos C57BL , Orgánulos/metabolismoRESUMEN
Complement factor H (CFH) is an important regulatory protein in the alternative pathway of the complement system, and CFH polymorphisms increase the genetic risk of age-related macular degeneration dramatically. These same human CFH variants have also been associated with dense deposit disease. To mechanistically study the function of CFH in the pathogenesis of these diseases, we created transgenic mouse lines using human CFH bacterial artificial chromosomes expressing full-length human CFH variants and crossed these to Cfh knockout (Cfh(-/-)) mice. Human CFH protein inhibited cleavage of mouse complement component 3 and factor B in plasma and in retinal pigment epithelium/choroid/sclera, establishing that human CFH regulates activation of the mouse alternative pathway. One of the mouse lines, which express relatively higher levels of CFH, demonstrated functional and structural protection of the retina owing to the Cfh deletion. Impaired visual function, detected as a deficit in the scotopic electroretinographic response, was improved in this transgenic mouse line compared with Cfh(-/-) mice, and transgenics had a thicker outer nuclear layer and less sub-retinal pigment epithelium deposit accumulation. In addition, expression of human CFH also completely protected the mice from developing kidney abnormalities associated with loss of CFH. These humanized CFH mice present a valuable model for study of the molecular mechanisms of age-related macular degeneration and dense deposit disease and for testing therapeutic targets.
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Enfermedades Renales/genética , Degeneración Macular/genética , Enfermedades de la Retina/genética , Animales , Coroides/patología , Complemento C3/metabolismo , Factor H de Complemento/genética , Factor H de Complemento/metabolismo , Cruzamientos Genéticos , Electrorretinografía , Humanos , Enfermedades Renales/patología , Degeneración Macular/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Retina/metabolismo , Enfermedades de la Retina/patología , Epitelio Pigmentado de la Retina/patología , Esclerótica/patología , OvinosRESUMEN
Autophagic dysregulation has been suggested in a broad range of neurodegenerative diseases including age-related macular degeneration (AMD). To test whether the autophagy pathway plays a critical role to protect retinal pigmented epithelial (RPE) cells against oxidative stress, we exposed ARPE-19 and primary cultured human RPE cells to both acute (3 and 24 h) and chronic (14 d) oxidative stress and monitored autophagy by western blot, PCR, and autophagosome counts in the presence or absence of autophagy modulators. Acute oxidative stress led to a marked increase in autophagy in the RPE, whereas autophagy was reduced under chronic oxidative stress. Upregulation of autophagy by rapamycin decreased oxidative stress-induced generation of reactive oxygen species (ROS), whereas inhibition of autophagy by 3-methyladenine (3-MA) or by knockdown of ATG7 or BECN1 increased ROS generation, exacerbated oxidative stress-induced reduction of mitochondrial activity, reduced cell viability, and increased lipofuscin. Examination of control human donor specimens and mice demonstrated an age-related increase in autophagosome numbers and expression of autophagy proteins. However, autophagy proteins, autophagosomes, and autophagy flux were significantly reduced in tissue from human donor AMD eyes and 2 animal models of AMD. In conclusion, our data confirm that autophagy plays an important role in protection of the RPE against oxidative stress and lipofuscin accumulation and that impairment of autophagy is likely to exacerbate oxidative stress and contribute to the pathogenesis of AMD.
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Autofagia , Degeneración Macular/patología , Estrés Oxidativo , Epitelio Pigmentado de la Retina/citología , Adenina/análogos & derivados , Adenina/química , Animales , Apolipoproteína E4/genética , Supervivencia Celular , Regulación de la Expresión Génica , Glutatión/metabolismo , Humanos , Peróxido de Hidrógeno/química , Lipofuscina/química , Potenciales de la Membrana , Ratones , Ratones Endogámicos C57BL , Especies Reactivas de Oxígeno/metabolismo , Retina/metabolismoRESUMEN
Variations in several complement genes are now known to be significant risk factors for the development of age-related macular degeneration (AMD). Despite dramatic effects on disease susceptibility, the underlying mechanisms by which common polymorphisms in complement proteins alter disease risk have remained unclear. Genetically modified mice in which the activity of the complement has been altered are available and can be used to investigate the role of complement in the pathogenesis of AMD. In this mini review, we will discuss some existing complement models of AMD and our efforts to develop and characterize the ocular phenotype in a variety of mice in which complement is either chronically activated or inhibited. A spectrum of complement dysregulation was modeled on the APOE4 AMD mouse model by crossing these mice to complement factor H knockout (cfh-/-) mice to test the impact of excess complement activation, and by crossing them to soluble-complement-receptor-1-related protein y (sCrry) mice, in which sCrry acts as a potent inhibitor of mouse complement acting in a manner similar to CFH. In addition, we have also generated humanized CFH mice expressing normal and risk variants of CFH.