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1.
Mol Cell ; 76(1): 126-137.e7, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31444107

RESUMO

A surprising complexity of ubiquitin signaling has emerged with identification of different ubiquitin chain topologies. However, mechanisms of how the diverse ubiquitin codes control biological processes remain poorly understood. Here, we use quantitative whole-proteome mass spectrometry to identify yeast proteins that are regulated by lysine 11 (K11)-linked ubiquitin chains. The entire Met4 pathway, which links cell proliferation with sulfur amino acid metabolism, was significantly affected by K11 chains and selected for mechanistic studies. Previously, we demonstrated that a K48-linked ubiquitin chain represses the transcription factor Met4. Here, we show that efficient Met4 activation requires a K11-linked topology. Mechanistically, our results propose that the K48 chain binds to a topology-selective tandem ubiquitin binding region in Met4 and competes with binding of the basal transcription machinery to the same region. The change to K11-enriched chain architecture releases this competition and permits binding of the basal transcription complex to activate transcription.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Proteômica/métodos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Transcrição Gênica , Ativação Transcricional , Ubiquitinação , Fatores de Transcrição de Zíper de Leucina Básica/química , Fatores de Transcrição de Zíper de Leucina Básica/genética , Sítios de Ligação , Ligação Competitiva , Cromatografia Líquida , Regulação Fúngica da Expressão Gênica , Lisina , Mutação , Ligação Proteica , Conformação Proteica , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Relação Estrutura-Atividade , Espectrometria de Massas em Tandem
2.
Proc Natl Acad Sci U S A ; 121(32): e2319091121, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39074279

RESUMO

Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.


Assuntos
Proteína Huntingtina , Lisossomos , Mitocôndrias , Proteínas de Ligação a RNA , Ubiquitina , Proteína Huntingtina/metabolismo , Proteína Huntingtina/genética , Lisossomos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Humanos , Ubiquitina/metabolismo , Mitocôndrias/metabolismo , Autofagia , Animais , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Camundongos , Ligação Proteica , Doença de Huntington/metabolismo , Doença de Huntington/genética , Doença de Huntington/patologia , Peptídeos/metabolismo
3.
Nucleic Acids Res ; 52(2): 643-659, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38038247

RESUMO

Mislocalization of overexpressed CENP-A (Cse4 in budding yeast, Cnp1 in fission yeast, CID in flies) contributes to chromosomal instability (CIN) in yeasts, flies, and human cells. Mislocalization of CENP-A is observed in many cancers and this correlates with poor prognosis. Structural mechanisms that contribute to mislocalization of CENP-A are poorly defined. Here, we show that interaction of histone H4 with Cse4 facilitates an in vivo conformational change in Cse4 promoting its mislocalization in budding yeast. We determined that Cse4 Y193A mutant exhibits reduced sumoylation, mislocalization, interaction with histone H4, and lethality in psh1Δ and cdc48-3 strains; all these phenotypes are suppressed by increased gene dosage of histone H4. We developed a new in vivo approach, antibody accessibility (AA) assay, to examine the conformation of Cse4. AA assay showed that wild-type Cse4 with histone H4 is in an 'open' state, while Cse4 Y193A predominantly exhibits a 'closed' state. Increased gene dosage of histone H4 contributes to a shift of Cse4 Y193A to an 'open' state with enhanced sumoylation and mislocalization. We provide molecular insights into how Cse4-H4 interaction changes the conformational state of Cse4 in vivo. These studies advance our understanding for mechanisms that promote mislocalization of CENP-A in human cancers.


Assuntos
Proteínas Cromossômicas não Histona , Histonas , Proteínas de Saccharomyces cerevisiae , Humanos , Centrômero/metabolismo , Proteína Centromérica A/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/genética , Histonas/metabolismo , Neoplasias/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Sumoilação
4.
FASEB J ; 38(17): e70046, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39259502

RESUMO

Large-conductance, calcium-activated potassium channels (BK channels) and the Na/K-ATPase are expressed universally in vascular smooth muscle. The Na/K-ATPase may act via changes in the intracellular Ca2+ concentration mediated by the Na/Ca exchanger (NCX) and via Src kinase. Both pathways are known to regulate BK channels. Whether BK channels functionally interact in vascular smooth muscle cells with the Na/K-ATPase remains to be elucidated. Thus, this study addressed the hypothesis that BK channels limit ouabain-induced vasocontraction. Rat mesenteric arteries were studied using isometric myography, FURA-2 fluorimetry and proximity ligation assay. The BK channel blocker iberiotoxin potentiated methoxamine-induced contractions. The cardiotonic steroid, ouabain (10-5 M), induced a contractile effect of IBTX at basal tension prior to methoxamine administration and enhanced the pro-contractile effect of IBTX on methoxamine-induced contractions. These facilitating effects of ouabain were prevented by the inhibition of either NCX or Src kinase. Furthermore, inhibition of NCX or Src kinase reduced the BK channel-mediated negative feedback regulation of arterial contraction. The effects of NCX and Src kinase inhibition were independent of each other. Co-localization of the Na/K-ATPase and the BK channel was evident. Our data suggest that BK channels limit ouabain-induced vasocontraction by a dual mechanism involving the NCX and Src kinase signaling. The data propose that the NCX and the Src kinase pathways, mediating the ouabain-induced activation of the BK channel, act in an independent manner.


Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Alta , Artérias Mesentéricas , Músculo Liso Vascular , Ouabaína , Trocador de Sódio e Cálcio , ATPase Trocadora de Sódio-Potássio , Quinases da Família src , Animais , Ouabaína/farmacologia , Quinases da Família src/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Ratos , Masculino , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Vasoconstrição/efeitos dos fármacos , Ratos Wistar , Contração Muscular/efeitos dos fármacos
5.
Lancet ; 402(10411): 1449-1458, 2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37696275

RESUMO

BACKGROUND: Geographic atrophy is an advanced form of dry age-related macular degeneration that can lead to irreversible vision loss and high burden of disease. We aimed to assess efficacy and safety of avacincaptad pegol 2 mg in reducing geographic atrophy lesion growth. METHODS: GATHER2 is a randomised, double-masked, sham-controlled, 24-month, phase 3 trial across 205 retina clinics, research hospitals, and academic institutions globally. To be eligible, patients had to be aged 50 years or older with non-centrepoint-involving geographic atrophy and best corrected visual acuity between 20/25 and 20/320 in the study eye. Eligible patients were randomly assigned (1:1) to monthly avacincaptad pegol 2 mg administered as a 100 µL intravitreal injection or sham for the first 12 months. Randomisation was performed using an interactive response technology system with stratification by factors known to be of prognostic importance in age-related macular degeneration. Patients, investigators, study centre staff, sponsor personnel, and data analysts were masked to treatment allocation. The primary endpoint was geographic atrophy lesion size measured by fundus autofluorescence at baseline, month 6, and month 12. Efficacy and safety analyses were done in the modified intention-to-treat and safety populations, respectively. This trial is registered with ClinicalTrials.gov, NCT04435366. FINDINGS: Between June 22, 2020, and July 23, 2021, 1422 patients were screened for eligibility, of whom 448 were enrolled and randomly assigned to avacincaptad pegol 2 mg (n=225) or sham (n=223). One patient in the sham group did not receive study treatment and was excluded from analyses. There were 154 (68%) female patients and 71 (32%) male patients in the avacincaptad pegol 2 mg group, and 156 (70%) female patients and 66 (30%) male patients in the sham group. From baseline to month 12, the mean rate of square-root-transformed geographic atrophy area growth was 0·336 mm/year (SE 0·032) with avacincaptad pegol 2 mg and 0·392 mm/year (0·033) with sham, a difference in growth of 0·056 mm/year (95% CI 0·016-0·096; p=0·0064), representing a 14% difference between the avacincaptad pegol 2 mg group and the sham group. Ocular treatment-emergent adverse events in the study eye occurred in 110 (49%) patients in the avacincaptad pegol 2 mg group and 83 (37%) in the sham group. There were no endophthalmitis, intraocular inflammation, or ischaemic optic neuropathy events over 12 months. To month 12, macular neovascularisation in the study eye occurred in 15 (7%) patients in the avacincaptad pegol 2 mg group and nine (4%) in the sham group, with exudative macular neovascularisation occurring in 11 (5%) in the avacincaptad pegol 2 mg group and seven (3%) in the sham group. INTERPRETATION: Monthly avacincaptad pegol 2 mg was well tolerated and showed significantly slower geographic atrophy growth over 12 months than sham treatment, suggesting that avacincaptad pegol might slow disease progression and potentially change the trajectory of disease for patients with geographic atrophy. FUNDING: Iveric Bio, An Astellas Company.

6.
Ophthalmology ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38878904

RESUMO

PURPOSE: Complications associated with intravitreal anti-VEGF therapies are reported inconsistently in the literature, thus limiting an accurate evaluation and comparison of safety between studies. This study aimed to develop a standardized classification system for anti-VEGF ocular complications using the Delphi consensus process. DESIGN: Systematic review and Delphi consensus process. PARTICIPANTS: Twenty-five international retinal specialists participated in the Delphi consensus survey. METHODS: A systematic literature search was conducted to identify complications of intravitreal anti-VEGF agent administration based on randomized controlled trials (RCTs) of anti-VEGF therapy. A comprehensive list of complications was derived from these studies, and this list was subjected to iterative Delphi consensus surveys involving international retinal specialists who voted on inclusion, exclusion, rephrasing, and addition of complications. Furthermore, surveys determined specifiers for the selected complications. This iterative process helped to refine the final classification system. MAIN OUTCOME MEASURES: The proportion of retinal specialists who choose to include or exclude complications associated with anti-VEGF administration. RESULTS: After screening 18 229 articles, 130 complications were categorized from 145 included RCTs. Participant consensus via the Delphi method resulted in the inclusion of 91 complications (70%) after 3 rounds. After incorporating further modifications made based on participant suggestions, such as rewording certain phrases and combining similar terms, 24 redundant complications were removed, leaving a total of 67 complications (52%) in the final list. A total of 14 complications (11%) met exclusion thresholds and were eliminated by participants across both rounds. All other remaining complications not meeting inclusion or exclusion thresholds also were excluded from the final classification system after the Delphi process terminated. In addition, 47 of 75 proposed complication specifiers (63%) were included based on participant agreement. CONCLUSIONS: Using the Delphi consensus process, a comprehensive, standardized classification system consisting of 67 ocular complications and 47 unique specifiers was established for intravitreal anti-VEGF agents in clinical trials. The adoption of this system in future trials could improve consistency and quality of adverse event reporting, potentially facilitating more accurate risk-benefit analyses. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

7.
Mol Cell Proteomics ; 21(1): 100175, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34763062

RESUMO

Protein ubiquitylation is an important posttranslational modification that governs most cellular processes. Signaling functions of ubiquitylation are very diverse and involve proteolytic as well as nonproteolytic events, such as localization, regulation of protein interactions, and control of protein activity. The intricacy of ubiquitin signaling is further complicated by several different polyubiquitin chain types that are likely recognized and interpreted by different protein readers. For example, K48-linked ubiquitin chains represent the most abundant chain topology and are the canonical degradation signals, but have been implicated in degradation-independent functions as well, likely requiring a variety of protein readers. Ubiquitin binding domains that interact with polyubiquitin chains are likely at the center of ubiquitin signal recognition and transmission, but their structure and selectivity are largely unexplored. Here we report identification and characterization of the ubiquitin interacting motif-like (UIML) domain of the yeast transcription factor Met4 as a strictly K48-polyubiquitin specific binding unit using methods such as biolayer interferometry (BLI), pull-down assays, and mass spectrometry. We further used the selective binding property to develop an affinity probe for purification of proteins modified with K48-linked polyubiquitin chains. The affinity probe has a Kd = 100 nM for K48 tetra-ubiquitin and shows no detectable interaction with either monoubiquitin or any other polyubiquitin chain configuration. Our results define a short strictly K48-linkage-dependent binding motif and present a new affinity reagent for the K48-polyubiquitin-modified proteome. Our findings benefit the ubiquitin field in analyses of the role of K48-linked polyubiquitylation and increase our understanding of chain topology selective ubiquitin chain recognition.


Assuntos
Poliubiquitina , Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Poliubiquitina/química , Poliubiquitina/metabolismo , Ligação Proteica , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Ubiquitina/metabolismo , Ubiquitinação
8.
Retina ; 44(10): 1704-1713, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39287533

RESUMO

PURPOSE: The Phase 3 Mylight study was designed to confirm clinical equivalence of proposed biosimilar aflibercept (SOK583A1; Sandoz [proposed biosimilar aflibercept, SDZ-AFL]) to its reference biologic (Eylea; Regeneron Pharmaceuticals, Inc; Bayer AG [reference aflibercept, Ref-AFL]). METHOD: Mylight was a prospective, double-masked, 2-arm, parallel Phase 3 study. Participants with neovascular age-related macular degeneration were randomized 1:1 to receive eight injections of SDZ-AFL (n = 244) or Ref-AFL (n = 240) over 48 weeks. The primary endpoint was mean change in best-corrected visual acuity score from baseline to Week 8. Secondary endpoints included anatomical outcomes, best-corrected visual acuity at Weeks 24 and 52, safety, and pharmacokinetics. RESULTS: Similarity in mean change in best-corrected visual acuity score was established between SDZ-AFL (n = 235) and Ref-AFL (n = 226) at Week 8 (difference: -0.3 [90% CI, -1.5 to 1.0]) and Week 52. No clinically meaningful differences occurred between groups in anatomical outcomes. Safety profiles were similar, with comparable incidences of treatment-related adverse events (SDZ-AFL: 2.5%; Ref-AFL: 2.9%). The incidence of anti-drug antibodies was similar between groups. Systemic free aflibercept concentrations 24 hours postdose were low and comparable between SDZ-AFL and Ref-AFL. CONCLUSION: Proposed biosimilar aflibercept matched reference aflibercept in efficacy, safety, and pharmacokinetics in participants with neovascular age-related macular degeneration. Therefore, this Phase 3 study confirmed biosimilarity of SDZ-AFL to Ref-AFL.


Assuntos
Inibidores da Angiogênese , Medicamentos Biossimilares , Injeções Intravítreas , Receptores de Fatores de Crescimento do Endotélio Vascular , Proteínas Recombinantes de Fusão , Acuidade Visual , Degeneração Macular Exsudativa , Humanos , Receptores de Fatores de Crescimento do Endotélio Vascular/administração & dosagem , Receptores de Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/efeitos adversos , Proteínas Recombinantes de Fusão/uso terapêutico , Método Duplo-Cego , Masculino , Feminino , Estudos Prospectivos , Idoso , Medicamentos Biossimilares/efeitos adversos , Medicamentos Biossimilares/uso terapêutico , Medicamentos Biossimilares/farmacocinética , Degeneração Macular Exsudativa/tratamento farmacológico , Degeneração Macular Exsudativa/diagnóstico , Degeneração Macular Exsudativa/fisiopatologia , Inibidores da Angiogênese/administração & dosagem , Inibidores da Angiogênese/efeitos adversos , Inibidores da Angiogênese/uso terapêutico , Inibidores da Angiogênese/farmacocinética , Idoso de 80 Anos ou mais , Resultado do Tratamento , Tomografia de Coerência Óptica , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Seguimentos , Fatores de Tempo
9.
Retina ; 44(6): 939-949, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38451179

RESUMO

PURPOSE: To develop professional guidelines for best practices for suprachoroidal space (SCS) injection, an innovative technique for retinal therapeutic delivery, based on current published evidence and clinical experience. METHODS: A panel of expert ophthalmologists reviewed current published evidence and clinical experience during a live working group meeting to define points of consensus and key clinical considerations to inform the development of guidelines for in-office SCS injection. RESULTS: Core consensus guidelines for in-office SCS injection were reached and reported by the expert panel. Current clinical evidence and physician experience supported SCS injection as a safe and effective method for delivering retinal and choroidal therapeutics. The panel established consensus on the rationale for SCS injection, including potential benefits relative to other intraocular delivery methods and current best practices in patient preparation, pre- and peri-injection management, SCS-specific injection techniques, and postinjection management and follow-up. CONCLUSION: These expert panel guidelines may support and promote standardization of SCS injection technique, with the goal of optimizing patient safety and outcomes. Some aspects of the procedure may reasonably be modified based on the clinical setting and physician judgment, as well as additional study.


Assuntos
Corioide , Humanos , Injeções Intraoculares , Doenças Retinianas , Guias de Prática Clínica como Assunto
10.
Nucleic Acids Res ; 50(6): 3276-3291, 2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35234920

RESUMO

Restricting the localization of CENP-A (Cse4 in Saccharomyces cerevisiae) to centromeres prevents chromosomal instability (CIN). Mislocalization of overexpressed CENP-A to non-centromeric chromatin contributes to CIN in budding and fission yeasts, flies, and humans. Overexpression and mislocalization of CENP-A is observed in cancers and is associated with increased invasiveness. Mechanisms that remove mislocalized CENP-A and target it for degradation have not been defined. Here, we report that Cdc48 and its cofactors Ufd1 and Npl4 facilitate the removal of mislocalized Cse4 from non-centromeric chromatin. Defects in removal of mislocalized Cse4 contribute to lethality of overexpressed Cse4 in cdc48,ufd1 andnpl4 mutants. High levels of polyubiquitinated Cse4 and mislocalization of Cse4 are observed in cdc48-3, ufd1-2 and npl4-1mutants even under normal physiological conditions, thereby defining polyubiquitinated Cse4 as the substrate of the ubiquitin directed segregase Cdc48Ufd1/Npl4. Accordingly, Npl4, the ubiquitin binding receptor, associates with mislocalized Cse4, and this interaction is dependent on Psh1-mediated polyubiquitination of Cse4. In summary, we provide the first evidence for a mechanism that facilitates the removal of polyubiquitinated and mislocalized Cse4 from non-centromeric chromatin. Given the conservation of Cdc48Ufd1/Npl4 in humans, it is likely that defects in such pathways may contribute to CIN in human cancers.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteína com Valosina/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Centrômero/metabolismo , Proteína Centromérica A/metabolismo , Cromatina/metabolismo , Histonas/metabolismo , Humanos , Proteólise , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Ubiquitina/metabolismo
11.
Ophthalmic Res ; 66(1): 653-663, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36626895

RESUMO

Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are used to treat wet age-related macular degeneration (wAMD); however, they are associated with a considerable treatment burden and poor real-world outcomes. The molecular size and charge of anti-VEGF agents influence drug pharmacokinetics in the vitreous and peak drug efficacy. This article reviews the established and novel strategies to prolong drug action, in the vitreal cavity, and thus reduce dosing frequency. Increased ocular residency can be attained by increasing drug size as with large molecules, such as KSI-301; adding polyethylene glycol to pegcetacoplan (APL-2) or avacincaptad pegol to increase molecular size; or binding to other targets that increase molecular size, such as vitreal albumin in the case of BI-X. Faricimab is a bispecific antibody in which the fragment crystallizable portion is engineered to prolong ocular residency and reduce systemic exposure. Conversely, small VEGF-binding molecules, such as brolucizumab, can be administered at higher clinical doses, with the potential for prolonged clinical activity versus larger molecules. Other important considerations include sustained drug delivery routes, such as the ranibizumab port delivery system or subconjunctival or suprachoroidal injection. More effective and longer-lasting treatments are needed for wAMD to prolong drug action and reduce dosing frequency. Several strategies are under investigation and the prevention of vision loss in patients with AMD or other retinal diseases may be attainable in the near future.


Assuntos
Inibidores da Angiogênese , Degeneração Macular Exsudativa , Humanos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Duração da Terapia , Ranibizumab/uso terapêutico , Degeneração Macular Exsudativa/tratamento farmacológico , Degeneração Macular Exsudativa/metabolismo , Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Injeções Intravítreas
12.
Proc Natl Acad Sci U S A ; 117(35): 21319-21327, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817489

RESUMO

Organisms can adapt to a broad spectrum of sudden and dramatic changes in their environment. These abrupt changes are often perceived as stress and trigger responses that facilitate survival and eventual adaptation. The ubiquitin-proteasome system (UPS) is involved in most cellular processes. Unsurprisingly, components of the UPS also play crucial roles during various stress response programs. The budding yeast SCFMet30 complex is an essential cullin-RING ubiquitin ligase that connects metabolic and heavy metal stress to cell cycle regulation. Cadmium exposure results in the active dissociation of the F-box protein Met30 from the core ligase, leading to SCFMet30 inactivation. Consequently, SCFMet30 substrate ubiquitylation is blocked and triggers a downstream cascade to activate a specific transcriptional stress response program. Signal-induced dissociation is initiated by autoubiquitylation of Met30 and serves as a recruitment signal for the AAA-ATPase Cdc48/p97, which actively disassembles the complex. Here we show that the UBX cofactor Shp1/p47 is an additional key element for SCFMet30 disassembly during heavy metal stress. Although the cofactor can directly interact with the ATPase, Cdc48 and Shp1 are recruited independently to SCFMet30 during cadmium stress. An intact UBX domain is crucial for effective SCFMet30 disassembly, and a concentration threshold of Shp1 recruited to SCFMet30 needs to be exceeded to initiate Met30 dissociation. The latter is likely related to Shp1-mediated control of Cdc48 ATPase activity. This study identifies Shp1 as the crucial Cdc48 cofactor for signal-induced selective disassembly of a multisubunit protein complex to modulate activity.


Assuntos
Proteínas F-Box/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Complexos Ubiquitina-Proteína Ligase/metabolismo , Proteína com Valosina/metabolismo , Cádmio , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mutação , Domínios Proteicos , Multimerização Proteica , Proteínas de Saccharomyces cerevisiae/genética , Saccharomycetales , Estresse Fisiológico
13.
PLoS Genet ; 16(2): e1008597, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32032354

RESUMO

Restricting the localization of the histone H3 variant CENP-A (Cse4 in yeast, CID in flies) to centromeres is essential for faithful chromosome segregation. Mislocalization of CENP-A leads to chromosomal instability (CIN) in yeast, fly and human cells. Overexpression and mislocalization of CENP-A has been observed in many cancers and this correlates with increased invasiveness and poor prognosis. Yet genes that regulate CENP-A levels and localization under physiological conditions have not been defined. In this study we used a genome-wide genetic screen to identify essential genes required for Cse4 homeostasis to prevent its mislocalization for chromosomal stability. We show that two Skp, Cullin, F-box (SCF) ubiquitin ligases with the evolutionarily conserved F-box proteins Met30 and Cdc4 interact and cooperatively regulate proteolysis of endogenous Cse4 and prevent its mislocalization for faithful chromosome segregation under physiological conditions. The interaction of Met30 with Cdc4 is independent of the D domain, which is essential for their homodimerization and ubiquitination of other substrates. The requirement for both Cdc4 and Met30 for ubiquitination is specifc for Cse4; and a common substrate for Cdc4 and Met30 has not previously been described. Met30 is necessary for the interaction between Cdc4 and Cse4, and defects in this interaction lead to stabilization and mislocalization of Cse4, which in turn contributes to CIN. We provide the first direct link between Cse4 mislocalization to defects in kinetochore structure and show that SCF-mediated proteolysis of Cse4 is a major mechanism that prevents stable maintenance of Cse4 at non-centromeric regions, thus ensuring faithful chromosome segregation. In summary, we have identified essential pathways that regulate cellular levels of endogenous Cse4 and shown that proteolysis of Cse4 by SCF-Met30/Cdc4 prevents mislocalization and CIN in unperturbed cells.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Instabilidade Cromossômica , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas F-Box/metabolismo , Proteínas Ligases SKP Culina F-Box/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Complexos Ubiquitina-Proteína Ligase/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Centrômero/metabolismo , Segregação de Cromossomos , Domínios Proteicos , Proteólise , Ubiquitinação
14.
Med Confl Surviv ; 39(4): 389-411, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37849278

RESUMO

We conducted a population-based survey in 2013 in Kampala, Uganda, to examine violence and mental health outcomes among self-settled male refugees from the Eastern Democratic Republic of Congo (DRC). Male DRC refugees aged 18+ years were sampled through respondent-driven sampling. Key interview domains included demographics, experiences of sexual and nonsexual violence, social support, PTSD, depression and suicide ideation. Data analysis was weighted to generate population-level estimates. We sampled 718 men (mean age: 33 years), most of whom had lived in North or South Kivu. Nonsexual violence, such as beatings (79.4%) and torture (63.8%), was frequent. A quarter (26.2%) had been raped; 49.9% of rape victims had been raped on multiple occasions, and 75.7% of rape victims had been gang raped. We estimated 52.8% had post-traumatic stress disorder (PTSD); 44.4% reported suicidal ideation. Numerous traumas were significantly (p < 0.05) associated with PTSD such as rape (adjusted odds ratio [aOR] = 1.82), war-related injuries (aOR = 2.90) or having been exposed to >15 traumas (compared to ≤10; aOR = 6.89). Traumata are frequent experiences in this self-settled male refugee population and are often accompanied by adverse mental health outcomes. Screening for trauma and adverse mental health outcomes and providing targeted services are paramount to improve these refugees' lives.


Assuntos
Estupro , Refugiados , Masculino , Humanos , Adulto , República Democrática do Congo/epidemiologia , Saúde Mental , Uganda/epidemiologia , Violência , Estupro/psicologia
15.
Ophthalmology ; 129(1): 54-63, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33957183

RESUMO

PURPOSE: This trial was conducted to investigate the clinical equivalence of the proposed biosimilar FYB201 and reference ranibizumab in patients with treatment-naive, subfoveal choroidal neovascularization caused by neovascular age-related macular degeneration (nAMD). DESIGN: This was a prospective, multicenter, evaluation-masked, parallel-group, 48-week, phase III randomized study. PARTICIPANTS: A total of 477 patients were randomly assigned to receive FYB201 (n = 238) or reference ranibizumab (n = 239). METHODS: Patients received FYB201 or reference ranibizumab 0.5 mg by intravitreal (IVT) injection in the study eye every 4 weeks. MAIN OUTCOME MEASURES: The primary end point was change from baseline in best-corrected visual acuity (BCVA) by Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 8 weeks before the third monthly IVT injection. Biosimilarity of FYB201 to its originator was assessed via a 2-sided equivalence test, with an equivalence margin in BCVA of 3 ETDRS letters. RESULTS: The BCVA improved in both groups, with a mean improvement of +5.1 (FYB201) and +5.6 (reference ranibizumab) ETDRS letters at week 8. The analysis of covariance (ANCOVA) least squares mean difference for the change from baseline between FYB201 and reference ranibizumab was -0.4 ETDRS letters with a 90% confidence interval (CI) of -1.6 to 0.9. Primary end point was met as the 90% CI was within the predefined equivalence margin. Adverse events were comparable between treatment groups. CONCLUSIONS: FYB201 is biosimilar to reference ranibizumab in terms of clinical efficacy and ocular and systemic safety in the treatment of patients with nAMD.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Medicamentos Biossimilares/uso terapêutico , Neovascularização de Coroide/tratamento farmacológico , Ranibizumab/uso terapêutico , Degeneração Macular Exsudativa/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Inibidores da Angiogênese/farmacocinética , Disponibilidade Biológica , Medicamentos Biossimilares/farmacocinética , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/metabolismo , Neovascularização de Coroide/fisiopatologia , Método Duplo-Cego , Feminino , Angiofluoresceinografia , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Ranibizumab/farmacocinética , Equivalência Terapêutica , Tomografia de Coerência Óptica , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual/fisiologia , Degeneração Macular Exsudativa/diagnóstico , Degeneração Macular Exsudativa/metabolismo , Degeneração Macular Exsudativa/fisiopatologia
16.
Ophthalmology ; 129(5): 498-508, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34871637

RESUMO

TOPIC: To investigate the effect of anti-vascular endothelial growth factor (VEGF) therapy on intraocular pressure (IOP) 12 and 24 months after initiation. CLINICAL RELEVANCE: It is unclear whether serial anti-VEGF injections result in sustained IOP increases. METHODS: Randomized controlled trials (RCTs) comparing anti-VEGF agents with each other or with controls for the treatment of neovascular age-related macular degeneration, retinal vein occlusions, or diabetic macular edema were included. Pairwise meta-analysis and Bayesian network meta-analysis examined the proportion of patients whose IOP (1) increased 5 mmHg or more from baseline on consecutive visits, (2) increased 10 mmHg or more from baseline at any visit, (3) was 21 mmHg or more on consecutive visits, (4) was 25 mmHg or more at any visit, (5) was 30 mmHg or more at any visit, (6) prompted initiation of IOP-lowering medications, or (7) increased as per the clinicians' discretion. Grading of Recommendations Assessments, Development, and Evaluations methodology informed the certainty of evidence. RESULTS: Twenty-six RCTs of 12 522 eyes were included. Aflibercept, bevacizumab, ranibizumab (0.3 mg and 0.5 mg), and noninjection controls were analyzed. Eighty-three of 84 network estimates for comparisons between anti-VEGF agents demonstrated no statistically significant difference (low to moderate certainty of evidence). Ranibizumab 0.5 mg showed higher rates than bevacizumab of IOP measurements of 30 mmHg or more at 12 months (low certainty of evidence). Fifty-three of 56 network estimates for comparisons between anti-VEGF agents and controls demonstrated no statistically significant difference (low to moderate certainty of evidence). Ranibizumab 0.5 mg showed higher rates of consecutive IOP increases of 5 mmHg or more at 24 months (low certainty of evidence) and higher rates of IOP increases as per the clinicians' discretion at 12 and 24 months (low and very low certainty of evidence, respectively). The 95% credible intervals in comparisons without statistically significant effects did not rule out important clinical effects. The certainty of evidence in these comparisons is limited by imprecision. CONCLUSION: This network meta-analysis does not show any clear difference in IOP increases 12 and 24 months after treatment initiation between anti-VEGF agents and controls. Imprecision precludes definitive conclusions.


Assuntos
Pressão Intraocular , Ranibizumab , Inibidores da Angiogênese/uso terapêutico , Bevacizumab/uso terapêutico , Humanos , Injeções Intravítreas , Metanálise em Rede , Ranibizumab/uso terapêutico , Receptores de Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Proteínas Recombinantes de Fusão , Fator A de Crescimento do Endotélio Vascular , Acuidade Visual
17.
Retina ; 42(12): 2243-2250, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36394884

RESUMO

BACKGROUND/PURPOSE: Anti-vascular endothelial growth factor therapies have proven effective in treating retinal diseases but come with a high financial burden to the patient and health care system. Biosimilar drugs present an opportunity to decrease the cost of these important ophthalmic medications, and several ophthalmic biosimilars are expected to be approved and enter the market in the coming years. The objectives of this review are to educate ophthalmologists on the safety and efficacy of biosimilars in ophthalmology in the United States and European Union, review the biosimilar manufacturing and approval process, and describe the upcoming ophthalmic biosimilars. RESULTS: Two ranibizumab biosimilars are currently approved in the United States and European Union. Additional ranibizumab biosimilars, as well as biosimilars for aflibercept and bevacizumab, are currently in clinical development. CONCLUSION: Biosimilar use in ophthalmology is expected to grow with the patent expiration of two major anti-vascular endothelial growth factor drugs, ranibizumab and aflibercept, and the development of an ophthalmology-specific bevacizumab biosimilar. Financial savings from biosimilar use in ophthalmology have the potential to reduce economic burden, increase treatment adherence, and ultimately improve health outcomes.


Assuntos
Medicamentos Biossimilares , Oftalmologia , Estados Unidos , Humanos , Medicamentos Biossimilares/uso terapêutico , Fatores de Crescimento Endotelial , Bevacizumab/uso terapêutico , Ranibizumab/uso terapêutico
18.
Retina ; 42(2): 265-273, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34561406

RESUMO

PURPOSE: To quantify ellipsoid zone (EZ) changes in integrity after epiretinal membrane (ERM) surgery, correlate findings to visual acuity, and determine predictors for prognosis. METHODS: A post hoc analysis of eyes undergoing ERM surgery pooled from the prospective DISCOVER intraoperative optical coherence tomography study and eyes undergoing conventional ERM surgery without intraoperative optical coherence tomography. Quantitative EZ features were extracted using a multilayer machine learning enabled automated segmentation platform after image analyst review/correction for segmentation accuracy. Visual acuity and EZ integrity were quantitatively assessed and correlated before and after ERM surgery. Multiple linear regression was performed to assess preoperative visual acuity and EZ features as predictors for improvement in visual acuity or EZ integrity. RESULTS: There were 177 eyes from 177 subjects that underwent ERM surgery from the DISCOVER and conventional arms. Improvement in visual acuity and multiple EZ integrity features was noted after ERM surgery, including EZ partial attenuation and EZ-retinal pigment epithelium (RPE) volume (P < 0.05). A reduction in EZ partial attenuation and increase in EZ-RPE central subfield thickness (EZ-RPE CST) was significantly correlated with improved visual acuity after ERM surgery (P < 0.05). More robust EZ-RPE CST at baseline predicted visual acuity improvement after ERM peel in regression modeling (ß = 0.005, P < 0.05). CONCLUSIONS: Longitudinal assessment of EZ features demonstrates significant postoperative improvement in multiple EZ integrity metrics after ERM surgery. Improving EZ integrity was correlated to improving the visual acuity. Ellipsoid zone integrity and visual acuity were significant predictors in regression modeling and may have value in clinical prognostication.


Assuntos
Membrana Epirretiniana/cirurgia , Segmento Externo das Células Fotorreceptoras da Retina/fisiologia , Vitrectomia , Idoso , Membrana Epirretiniana/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia
19.
Arch Orthop Trauma Surg ; 142(2): 343-353, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34338885

RESUMO

INTRODUCTION: Recently, the Cobra prostheses were introduced in the treatment of distal radius fractures (DRF) of elderly patients. Fracture prostheses provide an alternative treatment option for complex fractures where conservative therapy seems not acceptable and osteosynthesis seems not possible. Data reporting the feasibility of the Cobra prosthesis are sparse. Therefore, this retrospective follow-up study investigated the clinical and radiological mid-term outcome of the Cobra implant in complex DRFs of elderly patients. MATERIALS AND METHODS: Thirteen patients (mean age 73.5 years, range 65-87 years) were retrospectively evaluated with at least a 1-year follow-up after surgery. Objective and subjective clinical parameters as well as the radiological outcome and complications were analyzed. RESULTS: The mean follow-up period was 31.2 months. Seven cases required a cemented prosthesis. The mean relative range-of-motion compared to the healthy side was 72.3% and 51.8% for extension and flexion, respectively, and 87.9% and 85.7% for pronation and supination, respectively. The mean grip strength was 78.3% compared to the non-operated side. Eight patients were very satisfied, five patients were partly satisfied with the result. The DASH, PRWE, MHQ and Lyon-Scores averaged 39.1, 36.2, 64.9 and 63.3 points, respectively. The mean VAS-Score for pain was 1.1 at rest and 3.2 during activities. Perioperative complications included one dissection of the extensor pollicis longus tendon, one heterotopic ossification, one radiocarpal dislocation and two cases of an ulnar impaction syndrome due to implant subsidence. CONCLUSION: The prosthetic treatment of complex DRFs in elderly patients with the Cobra implant led to clinically and radiologically satisfactory mid-term results. The Cobra prosthesis still does not represent a gold standard but can be regarded as a feasible salvage option for complex DRFs when osteosyntheses may not be possible and non-operative treatment will lead to further functional restrictions and wrist pain during performing activities of daily life in high functional demand patients.


Assuntos
Fraturas do Rádio , Idoso , Idoso de 80 Anos ou mais , Animais , Elapidae , Seguimentos , Fixação Interna de Fraturas , Humanos , Próteses e Implantes , Fraturas do Rádio/diagnóstico por imagem , Fraturas do Rádio/cirurgia , Amplitude de Movimento Articular , Estudos Retrospectivos , Resultado do Tratamento , Articulação do Punho
20.
Arch Orthop Trauma Surg ; 142(4): 691-699, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35059823

RESUMO

INTRODUCTION: Distal radius fractures (DRFs) are very common. One of the most significant complications after intraarticular DRF is arthrofibrosis with loss of wrist motion and pain. Wrist arthroscopy has become increasingly popular in the treatment of DRF with the advantage of good visualization of the joint surface and soft tissue injuries. In intraarticular DRFs injuries of the dorsal capsule are a characteristic finding which potentially cause loss of wrist motion. In this study, we investigated if arthroscopic debridement of dorsal capsule injuries at time of surgical fixation provides superior outcomes compared to the same treatment without debridement. MATERIALS AND METHODS: Between 2013 and 2017, we included 42 patients who underwent arthroscopy-assisted palmar plating for intraarticular DRFs in a prospective randomized controlled study. In group A (intervention group), the dorsal capsule tears were debrided during primary surgery, while in group B these were left in place. Active range of motion (AROM), grip strength, subjective outcomes and radiographic results were assessed 3, 6 and 12 months after primary surgery. A subgroup analysis was performed for patient age, fracture severity and duration of immobilization. RESULTS: Arthroscopic debridement of the dorsal capsule improved AROM in patients over 60 years of age, more severe fractures (AO 23 C2/C3) and prolonged postoperative immobilization for more than two weeks, while it was not relevant for younger patients with simple fractures and short immobilization. CONCLUSIONS: Debridement of the injured dorsal capsule in arthroscopic-assisted surgical treatment of intraarticular DRFs can improve surgical performance and optimize patient outcomes in a specific subgroup of patients.


Assuntos
Fraturas do Rádio , Idoso , Desbridamento , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Fraturas do Rádio/cirurgia , Amplitude de Movimento Articular , Articulação do Punho
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