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1.
Ophthalmol Sci ; 4(6): 100583, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39263579

RESUMO

Purpose: To construct a comprehensive reference database (RDB) for a novel binocular automated perimeter. Design: A four-site prospective randomized clinical trial. Subjects and Controls: Three hundred fifty-six healthy subjects without ocular conditions that might affect visual function were categorized into 7 age groups. Methods: Subjects underwent comprehensive ocular examination of both eyes before enrollment. Using the TEMPO/IMOvifa automated perimeter (Topcon Healthcare/CREWT Medical Systems), each subject completed 4 binocular threshold visual field (VF) tests during a single visit: First, practice 24-2 and 10-2 tests were obtained from both eyes. Next, study 24-2 and 10-2 tests were obtained from both eyes. Test order of each sequence was randomized, and the tests were conducted under standard automated perimetry testing conditions: Goldmann stimulus size III, 3183 cd/m2 maximum stimulus intensity, and background intensity of 10 cd/m2, using AIZE-Rapid test strategy. Standard VF reliability indices were assessed. For each subject, 24-2 and 10-2 test results from 1 randomly selected eye were analyzed. Main Outcome Measures: Perimetric threshold sensitivity and reference limits for each test analysis parameter. Results: The ages of the study cohort were widely distributed, with a mean age (standard deviation [SD]) of 52.3 (18.5) years. Sex assignment was 44.0% male and 56.0% female. The majority of subjects self-identified as White (67.4%), followed by Black or African American (13.5%) and Asian (8.7%), with 14.6% self-identified as Hispanic or Latino ethnicity. Mean sensitivity (SD) was 29.1 (1.3) decibels (dB) for the 24-2 and 32.4 (1.0) dB for the 10-2 test. For the 24-2 and 10-2, mean sensitivity (SD) age-related changes averaged -0.06 (0.01) dB and -0.05 (0.01) dB per year, respectively. The normal range of pointwise threshold sensitivity increased with eccentricity and showed asymmetry around the mean, particularly notable in the 24-2 test. Mean (SD) binocular test duration was 3.18 (0.38) minutes (1 minute 35 seconds per eye) for the 24-2 test and 3.58 (0.43) minutes (1 minute 47 seconds per eye) for the 10-2 test. Conclusions: An RDB for the TEMPO/IMOvifa perimeter was established, highlighting the significance of considering both age and stimulus eccentricity in interpreting threshold VF test results. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

2.
bioRxiv ; 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38562864

RESUMO

Background: The resident astrocyte-retinal ganglion cell (RGC) lipoxin circuit is impaired during retinal stress, which includes ocular hypertension-induced neuropathy. Lipoxin B4 produced by homeostatic astrocytes directly acts on RGCs to increase survival and function in ocular hypertension-induced neuropathy. RGC death in the retina and axonal degeneration in the optic nerve are driven by the complex interactions between microglia and macroglia. Whether LXB4 neuroprotective actions include regulation of other cell types in the retina and/or optic nerve is an important knowledge gap. Methods: Cellular targets and signaling of LXB4 in the retina were defined by single-cell RNA sequencing. Retinal neurodegeneration was induced by injecting silicone oil into the anterior chamber of the mouse eyes, which induced sustained and stable ocular hypertension. Morphological characterization of microglia populations in the retina and optic nerve was established by MorphOMICs and pseudotime trajectory analyses. The pathways and mechanisms of action of LXB4 in the optic nerve were investigated using bulk RNA sequencing. Transcriptomics data was validated by qPCR and immunohistochemistry. Differences between experimental groups was assessed by Student's t-test and one-way ANOVA. Results: Single-cell transcriptomics identified microglia as a primary target for LXB4 in the healthy retina. LXB4 downregulated genes that drive microglia environmental sensing and reactivity responses. Analysis of microglial function revealed that ocular hypertension induced distinct, temporally defined, and dynamic phenotypes in the retina and, unexpectedly, in the distal myelinated optic nerve. Microglial expression of CD74, a marker of disease-associated microglia in the brain, was only induced in a unique population of optic nerve microglia, but not in the retina. Genetic deletion of lipoxin formation correlated with the presence of a CD74 optic nerve microglia population in normotensive eyes, while LXB4 treatment during ocular hypertension shifted optic nerve microglia toward a homeostatic morphology and non-reactive state and downregulated the expression of CD74. Furthermore, we identified a correlation between CD74 and phospho-phosphoinositide 3-kinases (p-PI3K) expression levels in the optic nerve, which was reduced by LXB4 treatment. Conclusion: We identified early and dynamic changes in the microglia functional phenotype, reactivity, and induction of a unique CD74 microglia population in the distal optic nerve as key features of ocular hypertension-induced neurodegeneration. Our findings establish microglia regulation as a novel LXB4 target in the retina and optic nerve. LXB4 maintenance of a homeostatic optic nerve microglia phenotype and inhibition of a disease-associated phenotype are potential neuroprotective mechanisms for the resident LXB4 pathway.

3.
Acta Neuropathol Commun ; 12(1): 58, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38610040

RESUMO

Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte reactivity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension. By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situ hybridization, qPCR, and lipidomic analyses, we discovered the formation of lipoxins and expression of the lipoxin pathway in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating the presence of this neuroprotective pathway across various species. Findings in the mouse retina identified significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-LOX activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Treatment with LXB4 amplified the lipoxin biosynthetic pathway by restoring and amplifying the generation of another member of the lipoxin family, LXA4, and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4's neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases, including retinal ganglion cell death in glaucoma.


Assuntos
Glaucoma , Lipoxinas , Hipertensão Ocular , Humanos , Animais , Camundongos , Lipoxinas/farmacologia , Astrócitos , Citocinas , Retina , Modelos Animais de Doenças , Primatas
4.
bioRxiv ; 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38293224

RESUMO

Glaucoma is a common neurodegenerative disease characterized by progressive degeneration of retinal ganglion cells (RGCs) and the retinal nerve fiber layer (RNFL), resulting in a gradual decline of vision. A recent study by our groups indicated that the levels of lipoxins A4 (LXA4) and B4 (LXB4) in the retina and optic nerve decrease following acute injury, and that restoring their function is neuroprotective. Lipoxins are members of the specialized pro-resolving mediator (SPM) family and play key roles to mitigate and resolve chronic inflammation and tissue damage. Yet, knowledge about lipoxin neuroprotective activity remains limited. Here we investigate the in vivo efficacy of exogenous LXA4 and LXB4 administration on the inner retina in a mouse model of chronic experimental glaucoma. To investigate the contribution of LXA4 signaling we used transgenic knockout (KO) mice lacking the two mouse LXA4 receptors (Fpr2/Fpr3-/-). Functional and structural changes of inner retinal neurons were assessed longitudinally using electroretinogram (ERG) and optical coherence tomography (OCT). At the end of the experiment, retinal samples were harvested for immunohistological assessment. While both lipoxins generated protective trends, only LXB4 treatment was significant, and consistently more efficacious than LXA4 in all endpoints. Both lipoxins also appeared to dramatically reduce Müller glial reactivity following injury. In comparison, Fpr2/Fpr3 deletion significantly worsened inner retinal injury and function, consistent with an essential protective role for endogenous LXA4. Together, these results support further exploration of lipoxin signaling as a treatment for glaucomatous neurodegeneration.

5.
J Neurosci ; 43(44): 7247-7263, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37914402

RESUMO

In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.


Assuntos
Axônios , Regeneração Nervosa , Axônios/metabolismo , Neurônios/fisiologia , RNA Mensageiro/metabolismo , Biossíntese de Proteínas
6.
Acta Neuropathol Commun ; 11(1): 154, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37749651

RESUMO

Astrocytes are a major category of glial support cell in the central nervous system and play a variety of essential roles in both health and disease. As our understanding of the diverse functions of these cells improves, the extent of heterogeneity between astrocyte populations has emerged as a key area of research. Retinal astrocytes, which form the direct cellular environment of retinal ganglion cells somas and axons, undergo a reactive response in both human glaucoma and animal models of the disease, yet their contributions to its pathology and progression remain relatively unknown. This gap in knowledge is largely a function of inadequate isolation techniques, driven in part by the sparseness of these cells and their similarities with the more abundant retinal Müller cells. Here, we present a novel method of isolating retinal astrocytes and enriching their RNA, tested in both normal and ocular hypertensive mice, a common model of experimental glaucoma. Our approach combines a novel enzyme assisted microdissection of retinal astrocytes with selective ribosome immunoprecipitation using the Ribotag method. Our microdissection method is rapid and preserves astrocyte morphology, resulting in a brief post-mortem interval and minimizing loss of RNA from distal regions of these cells. Both microdissection and Ribotag immunoprecipitation require a minimum of specialized equipment or reagents, and by using them in conjunction we are able to achieve > 100-fold enrichment of astrocyte RNA.


Assuntos
Astrócitos , Glaucoma , Humanos , Animais , Camundongos , Neuroglia , Sistema Nervoso Central , Células Ependimogliais
7.
bioRxiv ; 2023 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-37425861

RESUMO

Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte activity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension (n=40). By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situ hybridization, qPCR, and lipidomic analyses, we discovered the formation of lipoxins and expression of the lipoxin pathway in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating the presence of this neuroprotective pathway across various species. Findings in the mouse retina identified significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-LOX activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Treatment with LXB4 amplified the lipoxin biosynthetic pathway by restoring and amplifying the generation of another member of the lipoxin family, LXA4, and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4's neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases, including retinal ganglion cell death in glaucoma.

8.
J Cell Physiol ; 237(9): 3687-3702, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35862065

RESUMO

Glaucoma is a common neurodegenerative blinding disease that is closely associated with chronic biomechanical strain at the optic nerve head (ONH). Yet, the cellular injury and mechanosensing mechanisms underlying the resulting damage have remained critically unclear. We previously identified Annexin A4 (ANXA4) from a proteomic analyses of human ONH astrocytes undergoing pathological biomechanical strain that mimics glaucomatous conditions. Annexins are a family of calcium-dependent phospholipid binding proteins with key functions in plasma membrane repair (PMR); an active mechanism to limit and mend cellular injury that involves membrane and cytoskeletal reorganizations. However, a role for direct membrane damage and PMR has not been well studied in the context of biomechanical strain, such as that associated with glaucoma. Here we report that this moderate strain surprisingly damages cell membranes to increase permeability in a calcium-dependent manner, and induces rapid aggregation of ANXA4 at injury sites. ANXA4 loss-of-function increases permeability, while exogenous ANXA4 reduces it. Furthermore, ANXA4 aggregation is associated with F-actin dynamics in vitro, and remarkably this interaction and aggregation signature is also observed in the glaucomatous ONH in patient samples. Together these studies link moderate biomechanical strain with direct membrane damage and actin dynamics, and identify an active PMR role for ANXA4 in new model of cell injury associated with glaucoma pathogenesis.


Assuntos
Anexina A4 , Glaucoma , Anexina A4/metabolismo , Cálcio/metabolismo , Membrana Celular/metabolismo , Glaucoma/metabolismo , Humanos , Proteômica
9.
Mol Neurodegener ; 17(1): 23, 2022 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-35313950

RESUMO

Across neurodegenerative diseases, common mechanisms may reveal novel therapeutic targets based on neuronal protection, repair, or regeneration, independent of etiology or site of disease pathology. To address these mechanisms and discuss emerging treatments, in April, 2021, Glaucoma Research Foundation, BrightFocus Foundation, and the Melza M. and Frank Theodore Barr Foundation collaborated to bring together key opinion leaders and experts in the field of neurodegenerative disease for a virtual meeting titled "Solving Neurodegeneration". This "think-tank" style meeting focused on uncovering common mechanistic roots of neurodegenerative disease and promising targets for new treatments, catalyzed by the goal of finding new treatments for glaucoma, the world's leading cause of irreversible blindness and the common interest of the three hosting foundations. Glaucoma, which causes vision loss through degeneration of the optic nerve, likely shares early cellular and molecular events with other neurodegenerative diseases of the central nervous system. Here we discuss major areas of mechanistic overlap between neurodegenerative diseases of the central nervous system: neuroinflammation, bioenergetics and metabolism, genetic contributions, and neurovascular interactions. We summarize important discussion points with emphasis on the research areas that are most innovative and promising in the treatment of neurodegeneration yet require further development. The research that is highlighted provides unique opportunities for collaboration that will lead to efforts in preventing neurodegeneration and ultimately vision loss.


Assuntos
Glaucoma , Doenças Neurodegenerativas , Glaucoma/patologia , Humanos , Doenças Neurodegenerativas/patologia , Doenças Neurodegenerativas/terapia , Neuroproteção , Nervo Óptico/patologia
10.
Acad Med ; 97(10): 1467-1473, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35108233

RESUMO

Scientific research has been changing medical practice at an increasing pace. To keep up with this change, physicians of the future will need to be lifelong learners with the skills to engage with emerging science and translate it into clinical care. How medical schools can best prepare students for ongoing scientific change remains unclear. Adding to the challenge is reduced time allocated to basic science in curricula and rapid expansion of relevant scientific fields. A return to science with greater depth after clinical clerkships has been suggested, although few schools have adopted such curricula and implementation can present challenges. The authors describe an innovation at Harvard Medical School, the Advanced Integrated Science Courses (AISCs), which are taken after core clerkships. Students are required to take 2 such courses, which are offered in a variety of topics. Rather than factual content, the learning objectives are a set of generalizable skills to enable students to critically evaluate emerging research and its relationship to medical practice. Making these generalizable skills the defining principle of the courses has several important advantages: it allows standardization of acquired skills to be combined with diverse course topics ranging from basic to translational and population sciences; students can choose courses and projects aligned with their interests, thereby enhancing engagement, curiosity, and career relevance; schools can tailor course offerings to the interests of local faculty; and the generalizable skills delineate a unique purpose of these courses within the overall medical school curriculum. For the 3 years AISCs have been offered, students rated the courses highly and reported learning the intended skill set effectively. The AISC concept addresses the challenge of preparing students for this era of rapidly expanding science and should be readily adaptable to other medical schools.


Assuntos
Estágio Clínico , Currículo , Humanos , Aprendizagem , Faculdades de Medicina
11.
Am J Ophthalmol ; 233: 180-188, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34283973

RESUMO

PURPOSE: To analyze the relationship between rates of false positive (FP) responses and standard automated perimetry results. DESIGN: Prospective multicenter cross-sectional study. METHODS: One hundred twenty-six patients with manifest or suspect glaucoma were tested with Swedish Interactive Thresholding Algorithm (SITA) Standard, SITA Fast, and SITA Faster at each of 2 visits. We calculated intervisit differences in mean deviation (MD), visual field index (VFI), and number of statistically significant test points as a function of FP rates and also as a function of general height (GH). RESULTS: Increasing FP values were associated with higher MD values for all 3 algorithms, but the effects were small, 0.3 dB to 0.6 dB, for an increase of 10 percentage points of FP rate, and for VFI even smaller (0.6%-1.4%). Only small parts of intervisit differences were explained by FP (r2 values 0.00-0.11). The effects of FP were larger in severe glaucoma, with MD increases of 1.1 dB to 2.0 dB per 10 percentage points of FP, and r2 values ranging from 0.04 to 0.33. The numbers of significantly depressed total deviation points were affected only slightly, and pattern deviation probability maps were generally unaffected. GH was much more strongly related to perimetric outcomes than FP. CONCLUSIONS: Across 3 different standard automated perimetry thresholding algorithms, FP rates showed only weak associations with visual field test results, except in severe glaucoma. Current recommendations regarding acceptable FP ranges may require revision. GH or other analyses may be better suited than FP rates for identifying unreliable results in patients who frequently press the response button without having perceived stimuli.


Assuntos
Glaucoma , Testes de Campo Visual , Algoritmos , Estudos Transversais , Glaucoma/diagnóstico , Humanos , Estudos Prospectivos , Sensibilidade e Especificidade , Transtornos da Visão/diagnóstico , Campos Visuais
12.
Optom Vis Sci ; 98(5): 500-511, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33973918

RESUMO

SIGNIFICANCE: Planning for the effective delivery of eye care, on all levels, depends on an accurate and detailed knowledge of the optometric workforce and an understanding of demographic/behavioral trends to meet future needs of the public. PURPOSE: The purposes of this study were to assess the current and future supply of doctors of optometry and to examine in-depth trends related to (1) demographic shifts, (2) sex-based differences, (3) differences in practice behaviors in between self-employed and employed optometrists, and (4) the concept of additional capacity within the profession. METHODS: The 2017 National Optometry Workforce Survey (31 items) was distributed to 4050 optometrists, randomly sampled from a population of 45,033 currently licensed and practicing optometrists listed in the American Optometric Association's Optometry Master Data File. A stratified sampling method was applied to the population of optometrists using primary license state, age, and sex as variables to ensure a representative sample. RESULTS: With a response rate of 29% (1158 responses), the sample ensured a 95% confidence interval with a margin of error of <5%. Key results include finding no significant differences between men and women for hours worked (38.9 vs. 37.5), productivity (patient visits per hour, 2.0 vs. 1.9), or career options/professional growth satisfaction with 65% for both. The data indicate a likely range of additional patient capacity of 2.29 to 2.57 patients per week (5.05 to 5.65 million annually profession-wide). CONCLUSIONS: The optometric workforce for the next decade is projected to grow 0.6 to 0.7% more annually than the U.S. population. The study found additional capacity for the profession more limited than previously suggested. Findings also illustrate an evolving/equitable workforce based on sex, in terms of both productivity and satisfaction. The trend toward employed versus self-employed was marked with 44% reporting they are employed, up from 29% in 2012.


Assuntos
Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Mão de Obra em Saúde/estatística & dados numéricos , Optometristas/provisão & distribuição , Optometria/estatística & dados numéricos , Adulto , Idoso , Feminino , Pesquisa sobre Serviços de Saúde/estatística & dados numéricos , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Prática Profissional/estatística & dados numéricos , Inquéritos e Questionários , Estados Unidos
16.
Acad Med ; 95(11): 1687-1695, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32134787

RESUMO

As the U.S. health care system changes and technology alters how doctors work and learn, medical schools and their faculty are compelled to modify their curricula and teaching methods. In this article, educational leaders and key faculty describe how the Pathways curriculum was conceived, designed, and implemented at Harvard Medical School. Faculty were committed to the principle that educators should focus on how students learn and their ability to apply what they learn in the evaluation and care of patients. Using the best evidence from the cognitive sciences about adult learning, they made major changes in the pedagogical approach employed in the classroom and clinic. The curriculum was built upon 4 foundational principles: to enhance critical thinking and provide developmentally appropriate content; to ensure both horizontal integration between courses and vertical integration between phases of the curriculum; to engage learners, foster curiosity, and reinforce the importance of student ownership and responsibility for their learning; and to support students' transformation to a professional dedicated to the care of their patients and to their obligations for lifelong, self-directed learning.The practice of medicine is rapidly evolving and will undoubtedly change in multiple ways over the career of a physician. By emphasizing personal responsibility, professionalism, and thinking skills over content transfer, the authors believe this curriculum will prepare students not only for the first day of practice but also for an uncertain future in the biological sciences, health and disease, and the nation's health care system, which they will encounter in the decades to come.


Assuntos
Competência Clínica , Currículo , Educação de Graduação em Medicina , Aprendizagem Baseada em Problemas , Participação dos Interessados , Pensamento , Avaliação Educacional , Docentes de Medicina , Humanos , Avaliação das Necessidades , Ensino
17.
Elife ; 82019 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-31746735

RESUMO

Extrinsic cues trigger the local translation of specific mRNAs in growing axons via cell surface receptors. The coupling of ribosomes to receptors has been proposed as a mechanism linking signals to local translation but it is not known how broadly this mechanism operates, nor whether it can selectively regulate mRNA translation. We report that receptor-ribosome coupling is employed by multiple guidance cue receptors and this interaction is mRNA-dependent. We find that different receptors associate with distinct sets of mRNAs and RNA-binding proteins. Cue stimulation of growing Xenopus retinal ganglion cell axons induces rapid dissociation of ribosomes from receptors and the selective translation of receptor-specific mRNAs. Further, we show that receptor-ribosome dissociation and cue-induced selective translation are inhibited by co-exposure to translation-repressive cues, suggesting a novel mode of signal integration. Our findings reveal receptor-specific interactomes and suggest a generalizable model for cue-selective control of the local proteome.


Assuntos
Axônios/fisiologia , RNA Mensageiro/genética , Receptores de Superfície Celular/genética , Xenopus laevis/genética , Animais , Axônios/metabolismo , Biossíntese de Proteínas/genética , Proteoma/genética , Proteínas de Ligação a RNA/genética , Células Ganglionares da Retina/metabolismo , Ribossomos/genética , Transdução de Sinais , Xenopus laevis/crescimento & desenvolvimento
18.
Cell ; 177(3): 722-736.e22, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30955890

RESUMO

Insulin receptor (IR) signaling is central to normal metabolic control and dysregulated in prevalent chronic diseases. IR binds insulin at the cell surface and transduces rapid signaling via cytoplasmic kinases. However, mechanisms mediating long-term effects of insulin remain unclear. Here, we show that IR associates with RNA polymerase II in the nucleus, with striking enrichment at promoters genome-wide. The target genes were highly enriched for insulin-related functions including lipid metabolism and protein synthesis and diseases including diabetes, neurodegeneration, and cancer. IR chromatin binding was increased by insulin and impaired in an insulin-resistant disease model. Promoter binding by IR was mediated by coregulator host cell factor-1 (HCF-1) and transcription factors, revealing an HCF-1-dependent pathway for gene regulation by insulin. These results show that IR interacts with transcriptional machinery at promoters and identify a pathway regulating genes linked to insulin's effects in physiology and disease.


Assuntos
Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Receptor de Insulina/metabolismo , Animais , Linhagem Celular Tumoral , Cromatina/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Fator C1 de Célula Hospedeira/antagonistas & inibidores , Fator C1 de Célula Hospedeira/genética , Fator C1 de Célula Hospedeira/metabolismo , Humanos , Insulina/metabolismo , Insulina/farmacologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas , Ligação Proteica , Subunidades Proteicas/metabolismo , Interferência de RNA , RNA Polimerase II/metabolismo , RNA Interferente Pequeno/metabolismo , Receptor de Insulina/química , Transdução de Sinais/efeitos dos fármacos
19.
Acta Ophthalmol ; 97(5): e673-e679, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30690929

RESUMO

PURPOSE: The aim of this study was to assess the relationship between retinal blood oxygen saturation (SO2 ) and specific aqueous humour (AH) concentrations of proangiogenic biomarkers in diabetic patients with nonproliferative diabetic retinopathy (NPDR) and to compare them with those of matched control subjects. METHODS: The sample comprised 14 participants with mild-to-moderate NPDR (69.1 ± 6.6 years) and 17 age-matched healthy controls (69.7 ± 6.3 years); all participants were previously scheduled for routine cataract extraction with intraocular lens implantation. Multiplex cytokine analyses of specific biomarkers, including vascular endothelial growth factor A (VEGF-A), angiopoietin2 (Ang2), epidermal growth factor (EGF), hepatocyte growth factor (HGF) and interleukin-8 (IL-8) were performed by BioPlex 200 system. Six non-invasive hyperspectral retinal images were acquired. RESULTS: Mean SO2 was significantly higher in both arterioles (94.4 ± 1.9 versus 93.0 ± 1.6) and venules (64.4 ± 5.6 versus 55.9 ± 4.8) of NPDR than in the healthy controls (p < 0.001). AH levels of HGF (p = 0.018), Ang2 (p = 0.005) and IL-8 (p = 0.034) were significantly higher, and EGF (p = 0.030) was significantly lower in NPDR subjects. The study demonstrated a correlation between venular retinal blood oxygen saturation and proangiogenic factors HGF (r = 0.558, p = 0.038), Ang2 (r = 0.556, p = 0.039) and EGF (r = -0.554, p = 0.040), but did not find any correlation for IL-8 (r = 0.330, p = 0.249) even though this biomarker was significantly higher in the diabetic group. CONCLUSION: To our knowledge, the present study is the first report considering the association between SO2 and AH concentrations of protein biomarkers in diabetic retinopathy. The biomarkers of interest have been shown to participate in cell death, which may explain higher oxygen saturation in NPDR.


Assuntos
Humor Aquoso/metabolismo , Citocinas/metabolismo , Retinopatia Diabética/metabolismo , Oxigênio/sangue , Fluxo Sanguíneo Regional/fisiologia , Vasos Retinianos/fisiopatologia , Idoso , Biomarcadores/metabolismo , Retinopatia Diabética/diagnóstico , Feminino , Seguimentos , Humanos , Masculino , Oximetria , Vasos Retinianos/diagnóstico por imagem , Fatores de Tempo , Tomografia de Coerência Óptica/métodos , Acuidade Visual
20.
Exp Eye Res ; 183: 88-97, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30447198

RESUMO

Glaucoma describes a distinct optic neuropathy with complex etiology and a variety of associated risk factors, but with similar pathological endpoints. Risk factors such as age, increased intraocular pressure (IOP), low mean arterial pressure, and autoimmune disease, can all be associated with death of retinal ganglion cells (RGCs) and optic nerve head remodeling. Today, IOP management remains the standard of care, even though IOP elevation is not pathognomonic of glaucoma, and patients can continue to lose vision despite effective IOP control. A contemporary view of glaucoma as a complex, neurodegenerative disease has developed, along with the recognition of a need for new disease modifying retinal treatment strategies and improved outcomes. However, the distinction between risk factors triggering the disease process and retinal injury responses is not always clear. In this review, we attempt to distinguish between the various triggers, and their association with subsequent key RGC injury mechanisms. We propose that distinct glaucomatous risk factors result in similar retinal and optic nerve injury cascades, including oxidative and metabolic stress, glial reactivity, and altered inflammatory responses, which induce common molecular signals to induce RGC apoptosis. This organization forms a coherent disease framework and presents conserved targets for therapeutic intervention that are not limited to specific risk factors.


Assuntos
Glaucoma/complicações , Pressão Intraocular/fisiologia , Doenças Neurodegenerativas , Doenças do Nervo Óptico/etiologia , Nervo Óptico/patologia , Estresse Oxidativo , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Progressão da Doença , Glaucoma/diagnóstico , Humanos , Doenças do Nervo Óptico/diagnóstico , Doenças do Nervo Óptico/metabolismo , Células Ganglionares da Retina/metabolismo , Células Ganglionares da Retina/patologia , Fatores de Risco
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