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1.
Artigo em Inglês | MEDLINE | ID: mdl-39122834

RESUMO

Primary central nervous system lymphoma (PCNSL) is a potentially curable disease, but affected patients often struggle in everyday life due to disease- and therapy-associated sequelae. High-dose chemotherapy followed by autologous stem cell transplantation (HDC/ASCT) is the standard consolidation therapy, replacing whole brain radiation therapy (WBRT) amongst others due to less long-term cognitive decline. Nevertheless, white matter lesions (WML) are common findings in brain MRI after HDC/ASCT, but their clinical significance remains underexplored. Here, we correlate WML and brain atrophy with neuropsychological and quality-of-life evaluations collected post-treatment. We found that a significant part of PNCSL long-term survivors develop a high WML burden after HDC/ASCT, but we fail to associate them with specific patient or therapy characteristics. Intriguingly, even a high WML burden does not seem to affect QoL, basic neurocognition testing or performance status negatively. These results contrast findings in previous neuroimaging studies on healthy and cancer patients.

2.
Artigo em Inglês | MEDLINE | ID: mdl-39058998

RESUMO

PURPOSE: To describe the clinical course and treatment response of a case of Acute Zonal Occult Outer Retinopathy (AZOOR). METHODS: This is an observational case report. The examinations included ophthalmic examination, longitudinal multimodal imaging, visual field testing, electrophysiological recordings, serologic analyses and whole genome sequencing. RESULTS: In this report, the authors present the case of an otherwise healthy 33-year-old female with bilateral AZOOR manifestation. Other possible causes of the observed retinal lesions were ruled out by extensive diagnostic work-up. Treatment with oral prednisolone therapy led to temporal disease control but progression was observed after prednisolone discontinuation. A tapered oral prednisolone therapy in combination with adalimumab initiation prevented further progression for at least 21 months. CONCLUSION: Diagnosis of AZOOR is frequently complicated by the unspecific symptoms of the disease and significant number of differential diagnoses. Complete diagnostic work-up is important to rule out other etiologies. Due to the lack of randomized controlled trials, therapeutic decisions obligatorily rely on empiric treatment decisions in combination with frequent follow-up examinations.

3.
J Clin Med ; 13(14)2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39064106

RESUMO

Objectives: To investigate whether phakia affects the outcome of XEN-45 gel stent implantation in the treatment of pseudoexfoliative glaucoma (PXG). Methods: A retrospective, comparative cohort study of 30 phakic and 55 pseudophakic PXG patients who received the XEN-45 gel stent at a tertiary centre. The primary outcome measure was two-year success defined as a ≥20% lowering of intraocular pressure (IOP) and a target IOP of 6-21 mmHg. Success was complete without and qualified irrespective of antiglaucoma medication use. Further glaucoma surgery other than needling was regarded as a failure. The secondary outcome measures included changes in IOP, revision and complication rates. Results: The complete two-year success rates were 70% and 59% in the phakic and pseudophakic groups, respectively (p = 0.75, log-rank test), and the qualified rates were 80% and 72%, respectively (p = 0.89). The median IOP reduction from baseline was 54% in phakic, and 46% in pseudophakic eyes. While needling rates were similar, the incidence of early incisional bleb revisions was significantly higher in the phakic eyes (13% vs. 0% within 3 months; p = 0.0098, chi-square). Increasing after a year, significantly more pseudophakic eyes failed due to secondary glaucoma surgery (16% vs. 0%; p = 0.0191). Conclusions: The XEN-45 gel stent offers equally effective IOP control for both phakic and pseudophakic patients. However, the onset of bleb revisions and the necessity for secondary glaucoma surgery differed significantly between the groups.

4.
Front Ophthalmol (Lausanne) ; 4: 1348900, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38984139

RESUMO

Purpose: To investigate age-dependent wall to lumen ratio (WLR) reference values for healthy individuals in adaptive optics imaging (AO). WLR serves as an objective, dimensionless parameter for the evaluation of structural changes in vessels caused by conditions like arterial hypertension, diabetes or vascular stenosis. Methods: 50 right eyes of healthy individuals were examined by adaptive optics imaging. The central big arterioles and smaller arterial branches at least one disc diameter away from the optic disc, approximately above or below the macula were measured by the manufacturer's software. The wall-lumen-ratio (WLR), the wall cross-sectional area (WCSA) and lumen diameter (LD) were assessed. Subsequent data analysis was performed with a focus on variables including age, gender and blood pressure. Results: Normative values for WLR, WCSA and LD in 5 different age groups could be established. However, no significant differences between the age groups were found. Intra-subject comparisons revealed significantly higher WLRs on peripheral branches when compared to central arterioles. WLR showed in this normotensive cohort no relevant correlation with the systolic, diastolic and mean blood pressure. Gender and intraocular pressure had no influence on the vascular parameters. Conclusion: AO is capable of examining vascular alterations in arterioles at an almost microscopic level. Age did not seem to alter WLR, normotensive blood pressure parameters showed also no significant impact. AO-based vessel analysis may provide clinically useful biomarkers for cardiovascular health and should be tested in future studies.

5.
BMC Ophthalmol ; 24(1): 264, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38902667

RESUMO

BACKGROUND: Minimally invasive bleb surgery using the XEN-45 gel stent has not been established for the treatment of normal-tension glaucoma (NTG). The main objective of this study was to evaluate the long-term treatment efficacy and safety of XEN-45 in eyes with uncontrolled NTG. METHODS: A retrospective analysis of patients with NTG who underwent XEN-45 gel stent implantation at university hospital Tuebingen between 2016 and 2021. The primary outcome measure was surgical success after three years defined as lowering of intraocular pressure (IOP) of ≥ 20%, with target IOP between 6 and 15 mmHg. Success was complete without and qualified irrespective of topical antiglaucoma medication use. The need for further glaucoma surgery, except for needling, was regarded as a failure. The secondary outcome measures included changes in mean IOP, number of antiglaucoma medications, and needling and complication rates. RESULTS: Twenty-eight eyes from 23 patients were included in the final analysis. Complete and qualified success rates were 56.5% and 75% after three years, respectively. Mean postoperative IOP ± standard deviation decreased significantly after three years from 19.3 ± 2.0 mmHg at baseline to 13.7 ± 4.2 mmHg (n = 22; p < 0.0001). The median number of antiglaucoma medications decreased from 2 (range 0-4) to 0 after three years (range 0-3; p < 0.0001). Sixteen eyes (57%) required a median of 1 (range 1-3) needling procedures. One eye required further glaucoma surgery. No sight-threatening complications were observed. CONCLUSION: The XEN-45 stent is effective and safe for the long-term treatment of NTG. However, needling was frequently required to improve outcomes.


Assuntos
Implantes para Drenagem de Glaucoma , Pressão Intraocular , Glaucoma de Baixa Tensão , Stents , Humanos , Masculino , Feminino , Estudos Retrospectivos , Pressão Intraocular/fisiologia , Glaucoma de Baixa Tensão/cirurgia , Glaucoma de Baixa Tensão/fisiopatologia , Idoso , Pessoa de Meia-Idade , Resultado do Tratamento , Seguimentos , Acuidade Visual/fisiologia , Desenho de Prótese , Implantação de Prótese/métodos , Idoso de 80 Anos ou mais
6.
Curr Eye Res ; 49(8): 835-842, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38689527

RESUMO

PURPOSE: Artificial intelligence (AI)-tools hold great potential to compensate for missing resources in health-care systems but often fail to be implemented in clinical routine. Intriguingly, no-code and low-code technologies allow clinicians to develop Artificial intelligence (AI)-tools without requiring in-depth programming knowledge. Clinician-driven projects allow to adequately identify and address real clinical needs and, therefore, hold superior potential for clinical implementation. In this light, this study aimed for the clinician-driven development of a tool capable of measuring corneal lesions relative to total corneal surface area and eliminating inaccuracies in two-dimensional measurements by three-dimensional fitting of the corneal surface. METHODS: Standard slit-lamp photographs using a blue-light filter after fluorescein instillation taken during clinical routine were used to train a fully convolutional network to automatically detect the corneal white-to-white distance, the total fluorescent area and the total erosive area. Based on these values, the algorithm calculates the affected area relative to total corneal surface area and fits the area on a three-dimensional representation of the corneal surface. RESULTS: The developed algorithm reached dice scores >0.9 for an automated measurement of the relative lesion size. Furthermore, only 25% of conventional manual measurements were within a ± 10% range of the ground truth. CONCLUSIONS: The developed algorithm is capable of reliably providing exact values for corneal lesion sizes. Additionally, three-dimensional modeling of the corneal surface is essential for an accurate measurement of lesion sizes. Besides telemedicine applications, this approach harbors great potential for clinical trials where exact quantitative and observer-independent measurements are essential.


Assuntos
Algoritmos , Inteligência Artificial , Córnea , Úlcera da Córnea , Imageamento Tridimensional , Humanos , Úlcera da Córnea/diagnóstico , Córnea/patologia , Córnea/diagnóstico por imagem , Masculino , Feminino , Processamento de Imagem Assistida por Computador/métodos , Pessoa de Meia-Idade , Microscopia com Lâmpada de Fenda , Idoso , Adulto
8.
JMIR Form Res ; 8: e55742, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38551619

RESUMO

BACKGROUND: Cataract surgeries are among the most performed surgeries worldwide. A thorough patient education is essential to inform patients about the perioperative process and postoperative target results concerning the intraocular lens and objectives for visual outcomes. However, addressing all relevant aspects and questions is time-consuming. Mobile apps can facilitate this process for both patients and physicians and thus be beneficial. However, the success of such an app depends on its user friendliness and acceptance by patients. OBJECTIVE: This study aimed to evaluate the user friendliness and acceptance of a cataract surgery education app on mobile devices among patients undergoing cataract surgery, the characteristics of patients who benefit the most from app use, and the influence of the app on patient satisfaction with treatment. METHODS: All patients who underwent cataract surgery at an ophthalmological practice from August 2020 to July 2021 were invited to participate in this randomized controlled trial. Out of 493 invited patients, 297 (60.2%) were enrolled in this study. Patients were randomized into 3 different groups. Half of the patients were offered to participate in Group 1 with use of the "Patient Journey" app. However, if they decided not to use the app, they were included in Group 2 (app denial). The other half of the patients were included in Group 3 (control) with no use of the app and with information provided conventionally. The app provided general information on the ophthalmological center, surgeons, cataract, and treatment options. Different questionnaires were used in all 3 groups to evaluate satisfaction with the perioperative process. Group 1 evaluated the app. Demographic characteristics, such as age, gender, and educational degree, were assessed. RESULTS: Group 1 included 77 patients (median age 69 years). Group 2 included 61 patients, and their median age was higher (median age 79 years). Group 3 included 159 patients (median age 74 years). There was no difference in satisfaction with the perioperative process and clinic between the 3 groups. Almost all app users appreciated the digital details provided for the organization and the information on the surgery. Age did not play a major role in appreciation of the app. Female patients tended to appreciate the information provided more than male patients. Patients who did not have a higher university degree experienced more benefits from the informational content of the app and were the most satisfied with the information. However, male patients and academics were in general more aware of technology and handled the app more easily. CONCLUSIONS: The app showed high user friendliness and acceptance, and could particularly benefit specific patient groups. App users demonstrated a noninferior high satisfaction with the treatment in the ophthalmological center in comparison with patients who were informed about the surgery only conventionally.

9.
J Ophthalmic Inflamm Infect ; 14(1): 3, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38252394

RESUMO

BACKGROUND: Capnocytophaga is a bacterium frequently found in the oral flora of dogs and cats (e.g. Capnocytophaga canimorsus) and humans (e.g. Capnocytophaga gingivalis). Among Capnocytophaga related ocular infections, fulminant endophthalmitis is a rare but sight-threatening clinical manifestation. CASE PRESENTATION: A 35-year-old previously healthy patient presented after a cat bite into the left upper and lower eyelid and nasal part of the conjunctiva of the left eye. At initial consultation, the corrected visual acuity was 0.8 in decimal scale and a detailed clinical examination revealed no evidence of ocular penetration. However, daily follow-up examinations under local therapy revealed a progressive intraocular inflammation, therefore the decision was made to perform a diagnostic vitrectomy with intravitreal and systemic antibiotic treatment. Capnocytophaga felis was detected as the cause of endophthalmitis and the initiated treatment resulted in quick morphological and functional recovery of the left eye. After surgery of secondary cataract, visual acuity improved from hand motion preoperatively to 1.0 postoperatively. CONCLUSIONS: Early recognition as well as prompt and effective treatment of animal bite associated endophthalmitis is essential for good visual recovery and functional outcome. Furthermore, this case highlights the importance of daily follow-up examinations, even in the absence of signs of ocular penetration and intraocular inflammation, to enable prompt and effective treatment initiation. Given the negative results in bacterial culture, we additionally emphasize the value of sequencing-based microbiological diagnostics in unclear cases.

10.
Acta Ophthalmol ; 102(3): e358-e366, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-37715554

RESUMO

PURPOSE: To investigate the changes in retinal arterial architecture after treatment with voretigene neparvovec in patients with retinal dystrophy caused by bi-allelic mutations in the RPE65 gene. METHODS: Sixteen eyes treated with voretigene neparvovec at the University Eye Clinic in Tuebingen, Germany, underwent adaptive optics ophthalmoscopy (AO) imaging at baseline and 2 weeks, 1, 3, 6 and 12 months after treatment. Follow-up was performed in six eyes of four patients. For each eye, five different positions at arterial vessels were selected and the wall-to-lumen ratio (WLR), the lumen diameter (LD) and the wall cross-sectional area (WCSA) were measured by the manufacturer's software over the observational period. RESULTS: Vast retinal atrophy dominated all gained AO images. WLR fluctuated in the observation period without statistically significant change. LD and WCSA changed significantly after 2 weeks from the baseline examination and returned to values similar to baseline thereafter. There were no signs of inflammation such as macrophages or perivascular accumulated fluid visible. CONCLUSION: AO imaging of the retinal vessels in RPE65-associated retinal dystrophies (IRD) is challenging. There was no change in the retinal arterial vasculature over the observation period of 12 months that would indicate inflammatory changes. Decrease of the LD and WCSA shortly after treatment might be caused by the perioperative prednisolone intake. AO of retinal vessels can be used as a diagnostic module to complement monitoring the disease and effects of genetic treatments if the acquisition is possible in selected cases.


Assuntos
Arteríolas , Distrofias Retinianas , Vasos Retinianos , Humanos , Oftalmoscopia , Distrofias Retinianas/diagnóstico , Distrofias Retinianas/genética
11.
Cancers (Basel) ; 15(3)2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36765625

RESUMO

Primary central nervous system lymphomas (PCNSL) are rare and associated with an adverse prognosis. High-dose chemotherapy followed by autologous stem cell transplantation (HDC/ASCT) improves progression free (PFS) and overall survival (OS) but neurocognition, performance status and quality of life (QoL) in patient-reported outcome (PRO) after HDC/ASCT remains underexplored. Especially elderly patients may insufficiently recover from this demanding therapy. Therefore, this single-center analysis investigated all PCNSL patients who received HDC/ASCT at the University Hospital Tübingen from 2006-2021 (n = 40, median age 60.5 years) in a retrospective manner. The 2-year PFS/OS was 78.7%/77.3%, respectively, without significant differences between the tested age-groups (≤60 vs. >60 years, p = 0.531/p = 0.334). Higher Thiotepa dosage was an independent predictor for better OS (p = 0.018). Additionally, a one-time prospective, cross-sectional analysis after HDC/ASCT in the same cohort was performed (n = 31; median follow-up 45 months). Here, the median ECOG improved by HDC/ASCT from 1 to 0 and mini-mental state examinations revealed unimpaired neurocognitive functioning (median 28 pts.). PRO data collected by EORTC QLQ-C30 showed a good QoL in both age groups with an average global health status (GHS) of 68.82% (≤60y: 64.72%, >60y: 74.14%). Together, our data indicate that HDC/ASCT is an effective therapy with respect to disease control, overall health status and quality of life, irrespective of patient age.

12.
Prog Retin Eye Res ; 96: 101154, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-36513584

RESUMO

Despite comprehensive research efforts over the last decades, the pathomechanisms of age-related macular degeneration (AMD) remain far from being understood. Large-scale genome wide association studies (GWAS) were able to provide a defined set of genetic aberrations which contribute to disease risk, with the strongest contributors mapping to distinct regions on chromosome 1 and 10. While the chromosome 1 locus comprises factors of the complement system with well-known functions, the role of the 10q26-locus in AMD-pathophysiology remains enigmatic. 10q26 harbors a cluster of three functional genes, namely PLEKHA1, ARMS2 and HTRA1, with most of the AMD-associated genetic variants mapping to the latter two genes. High linkage disequilibrium between ARMS2 and HTRA1 has kept association studies from reliably defining the risk-causing gene for long and only very recently the genetic risk region has been narrowed to ARMS2, suggesting that this is the true AMD gene at this locus. However, genetic associations alone do not suffice to prove causality and one or more of the 14 SNPs on this haplotype may be involved in long-range control of gene expression, leaving HTRA1 and PLEKHA1 still suspects in the pathogenic pathway. Both, ARMS2 and HTRA1 have been linked to extracellular matrix homeostasis, yet their exact molecular function as well as their role in AMD pathogenesis remains to be uncovered. The transcriptional regulation of the 10q26 locus adds an additional level of complexity, given, that gene-regulatory as well as epigenetic alterations may influence expression levels from 10q26 in diseased individuals. Here, we provide a comprehensive overview on the 10q26 locus and its three gene products on various levels of biological complexity and discuss current and future research strategies to shed light on one of the remaining enigmatic spots in the AMD landscape.


Assuntos
Degeneração Macular , Serina Endopeptidases , Humanos , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Estudo de Associação Genômica Ampla , Proteínas/genética , Proteínas/metabolismo , Degeneração Macular/genética , Degeneração Macular/metabolismo , Regulação da Expressão Gênica , Polimorfismo de Nucleotídeo Único , Genótipo , Predisposição Genética para Doença
13.
Antioxidants (Basel) ; 10(12)2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34943047

RESUMO

Age-related macular degeneration (AMD) is a complex degenerative disease of the retina with multiple risk-modifying factors, including aging, genetics, and lifestyle choices. The combination of these factors leads to oxidative stress, inflammation, and metabolic failure in the retinal pigment epithelium (RPE) with subsequent degeneration of photoreceptors in the retina. The alternative complement pathway is tightly linked to AMD. In particular, the genetic variant in the complement factor H gene (CFH), which leads to the Y402H polymorphism in the factor H protein (FH), confers the second highest risk for the development and progression of AMD. Although the association between the FH Y402H variant and increased complement system activation is known, recent studies have uncovered novel FH functions not tied to this activity and highlighted functional relevance for intracellular FH. In our previous studies, we show that loss of CFH expression in RPE cells causes profound disturbances in cellular metabolism, increases the vulnerability towards oxidative stress, and modulates the activation of pro-inflammatory signaling pathways, most importantly the NF-kB pathway. Here, we silenced CFH in hTERT-RPE1 cells to investigate the mechanism by which intracellular FH regulates RPE cell homeostasis. We found that silencing of CFH results in hyperactivation of mTOR signaling along with decreased mitochondrial respiration and that mTOR inhibition via rapamycin can partially rescue these metabolic defects. To obtain mechanistic insight into the function of intracellular FH in hTERT-RPE1 cells, we analyzed the interactome of FH via immunoprecipitation followed by mass spectrometry-based analysis. We found that FH interacts with essential components of the ubiquitin-proteasomal pathway (UPS) as well as with factors associated with RB1/E2F signalling in a complement-pathway independent manner. Moreover, we found that FH silencing affects mRNA levels of the E3 Ubiquitin-Protein Ligase Parkin and PTEN induced putative kinase (Pink1), both of which are associated with UPS. As inhibition of mTORC1 was previously shown to result in increased overall protein degradation via UPS and as FH mRNA and protein levels were shown to be affected by inhibition of UPS, our data stress a potential regulatory link between endogenous FH activity and the UPS.

14.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445430

RESUMO

Age-related macular degeneration (AMD), the leading cause of vision loss in the elderly, is a degenerative disease of the macula, where retinal pigment epithelium (RPE) cells are damaged in the early stages of the disease, and chronic inflammatory processes may be involved. Besides aging and lifestyle factors as drivers of AMD, a strong genetic association to AMD is found in genes of the complement system, with a single polymorphism in the complement factor H gene (CFH), accounting for the majority of AMD risk. However, the exact mechanism of CFH dysregulation confers such a great risk for AMD and its role in RPE cell homeostasis is unclear. To explore the role of endogenous CFH locally in RPE cells, we silenced CFH in human hTERT-RPE1 cells. We demonstrate that endogenously expressed CFH in RPE cells modulates inflammatory cytokine production and complement regulation, independent of external complement sources, or stressors. We show that loss of the factor H protein (FH) results in increased levels of inflammatory mediators (e.g., IL-6, IL-8, GM-CSF) and altered levels of complement proteins (e.g., C3, CFB upregulation, and C5 downregulation) that are known to play a role in AMD. Moreover, our results identify the NF-κB pathway as the major pathway involved in regulating these inflammatory and complement factors. Our findings suggest that in RPE cells, FH and the NF-κB pathway work in synergy to maintain inflammatory and complement balance, and in case either one of them is dysregulated, the RPE microenvironment changes towards a proinflammatory AMD-like phenotype.


Assuntos
Citocinas/metabolismo , Inativação Gênica , Degeneração Macular/genética , Epitélio Pigmentado da Retina/imunologia , Linhagem Celular , Fator H do Complemento/genética , Proteínas do Sistema Complemento/metabolismo , Citocinas/genética , Regulação da Expressão Gênica , Humanos , Degeneração Macular/imunologia , Modelos Biológicos , NF-kappa B/genética , NF-kappa B/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Transdução de Sinais
15.
J Mol Biol ; 432(4): 930-951, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-31794729

RESUMO

The mechanisms by which protein complexes convert from functional to pathogenic are the subject of intensive research. Here, we report how functionally unfavorable protein interactions can be induced by structural fuzziness, i.e., by persisting conformational disorder in protein complexes. We show that extreme disorder in the bound state transforms the intrinsically disordered protein SERF1a from an RNA-organizing factor into a pathogenic enhancer of alpha-synuclein (aSyn) amyloid toxicity. We demonstrate that SERF1a promotes the incorporation of RNA into nucleoli and liquid-like artificial RNA-organelles by retaining an unusually high degree of conformational disorder in the RNA-bound state. However, this type of structural fuzziness also determines an undifferentiated interaction with aSyn. RNA and aSyn both bind to one identical, positively charged site of SERF1a by an analogous electrostatic binding mode, with similar binding affinities, and without any observable disorder-to-order transition. The absence of primary or secondary structure discriminants results in SERF1a being unable to select between nucleic acid and amyloidogenic protein, leading the pro-amyloid aSyn:SERF1a interaction to prevail in the cytosol under conditions of cellular stress. We suggest that fuzzy disorder in SERF1a complexes accounts for an adverse gain-of-interaction which favors toxic binding to aSyn at the expense of nontoxic RNA binding, thereby leading to a functionally distorted and pathogenic process. Thus, structural fuzziness constitutes a direct link between extreme conformational flexibility, amyloid aggregation, and the malfunctioning of RNA-associated cellular processes, three signatures of neurodegenerative proteinopathies.


Assuntos
Proteínas do Tecido Nervoso/metabolismo , RNA/química , alfa-Sinucleína/metabolismo , Animais , Citosol/metabolismo , Humanos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Camundongos , Proteínas do Tecido Nervoso/química , Ácidos Nucleicos/química , Ligação Proteica , RNA/metabolismo , Eletricidade Estática , alfa-Sinucleína/química
16.
J Mol Biol ; 431(14): 2581-2598, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31034892

RESUMO

The recent discovery of biologically active fully disordered, so called random fuzzy protein-protein interactions leads to the question of how the high flexibility of these protein complexes correlates to aggregation and pathologic misfolding. We identify the structural mechanism by which a random fuzzy protein complex composed of the intrinsically disordered proteins alpha-Synuclein and SERF1a is able to potentiate cytotoxic aggregation. A structural model derived from an integrated NMR/SAXS analysis of the reconstituted aSyn:SERF1a complex enabled us to observe the partial deprotection of one precise aSyn amyloid nucleation element in the fully unstructured ensemble. This minimal exposure was sufficient to increase the amyloidogenic tendency of SERF1a-bound aSyn. Our findings provide a structural explanation of the previously observed pro-amyloid activity of SERF1a. They further demonstrate that random fuzziness can trigger a structurally organized disease-associated reaction such as amyloid polymerization.


Assuntos
Amiloide/química , Encéfalo/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuroblastoma/metabolismo , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Sequência de Aminoácidos , Animais , Encéfalo/citologia , Humanos , Proteínas Intrinsicamente Desordenadas/química , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Proteínas do Tecido Nervoso/química , Neuroblastoma/patologia , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Homologia de Sequência
17.
Cell Rep ; 2(2): 358-71, 2012 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-22854022

RESUMO

The inherent cytotoxicity of aberrantly folded protein aggregates contributes substantially to the pathogenesis of amyloid diseases. It was recently shown that a class of evolutionary conserved proteins, called MOAG-4/SERF, profoundly alter amyloid toxicity via an autonomous but yet unexplained mode. We show that the biological function of human SERF1a originates from its atypical ability to specifically distinguish between amyloid and nonamyloid aggregation. This inherently unstructured protein directly affected the aggregation kinetics of a broad range of amyloidogenic proteins in vitro, while being inactive against nonamyloid aggregation. A representative biophysical analysis of the SERF1a:α-synuclein (aSyn) complex revealed that the amyloid-promoting activity resulted from an early and transient interaction, which was sufficient to provoke a massive increase of soluble aSyn amyloid nucleation templates. Therefore, the autonomous amyloid-modifying activity of SERF1a observed in living organisms relies on a direct and dedicated manipulation of the early stages in the amyloid aggregation pathway.


Assuntos
Amiloide/química , Proteínas do Tecido Nervoso/química , alfa-Sinucleína/química , Amiloide/genética , Amiloide/metabolismo , Animais , Humanos , Camundongos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Solubilidade , Suínos , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo
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