Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 85
Filter
1.
Transl Vis Sci Technol ; 13(7): 8, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38980260

ABSTRACT

Purpose: To describe optical coherence tomography angiography (OCTA)-guided navigated laser photocoagulation (LP) using the Navilas Laser System for treating retinal hemangioblastomas (RHs) associated with von Hippel-Lindau disease (VHLD). Methods: Patients with VHLD were screened using ophthalmoscopy and widefield OCTA. Detected RHs were classified with regard to tumor morphology (endophytic, sessile, exophytic, recurrent) and size. Then, 6 × 6- or 3 × 3-mm2 en face OCTA scans of the RHs were uploaded to the Navilas system, generating a merged image combining the scan and Navilas fundus photography. LP was planned by placing laser spots in the OCTA scan and executed with the Navilas system. Treatment efficacy was assessed by conducting OCTA scans immediately after LP and at follow-up visits. Results: Fifteen RHs were detected in 10 patients (median, one RH; range, one to four). Twelve RHs were treatment naive (exophytic [3], sessile [3], and endophytic [6]), and there were three recurrent RHs in pretreated areas. Total applied energy per tumor correlated with tumor size (P < 0.001). After a mean first follow-up of 3.6 ± 1.5 months (range, 0.9-5.3), nine RHs exhibited complete regression (60%), five partial regression (33.3%), and one no regression (6.7%). No correlation between tumor morphology and treatment success was observed (P = 0.32). However, a correlation between treatment success and tumor size trended toward significance (P = 0.08), with a 100% success rate observed for small RHs. Conclusions: OCTA-guided LP via the Navilas Laser System is a promising technique, especially beneficial for targeting small RHs. Combining OCTA and ophthalmoscopy improves tumor detection, underscoring the utility of this approach. Translational Relevance: OCTA-guided LP enables highly precise and safe treatment of early-stage RHs, minimizing possible complications caused by LP or the tumor itself.


Subject(s)
Hemangioblastoma , Laser Coagulation , Retinal Neoplasms , Tomography, Optical Coherence , von Hippel-Lindau Disease , Humans , Hemangioblastoma/surgery , Hemangioblastoma/diagnostic imaging , Male , Female , von Hippel-Lindau Disease/complications , von Hippel-Lindau Disease/surgery , Laser Coagulation/methods , Adult , Tomography, Optical Coherence/methods , Retinal Neoplasms/surgery , Retinal Neoplasms/diagnostic imaging , Retinal Neoplasms/pathology , Middle Aged , Fluorescein Angiography/methods , Young Adult , Treatment Outcome , Surgery, Computer-Assisted/methods
2.
Sci Adv ; 10(29): eadn4582, 2024 Jul 19.
Article in English | MEDLINE | ID: mdl-39018392

ABSTRACT

The pyruvate dehydrogenase complex (PDHc) is a key megaenzyme linking glycolysis with the citric acid cycle. In mammalian PDHc, dihydrolipoamide acetyltransferase (E2) and the dihydrolipoamide dehydrogenase-binding protein (E3BP) form a 60-subunit core that associates with the peripheral subunits pyruvate dehydrogenase (E1) and dihydrolipoamide dehydrogenase (E3). The structure and stoichiometry of the fully assembled, mammalian PDHc or its core remained elusive. Here, we demonstrate that the human PDHc core is formed by 48 E2 copies that bind 48 E1 heterotetramers and 12 E3BP copies that bind 12 E3 homodimers. Cryo-electron microscopy, together with native and cross-linking mass spectrometry, confirmed a core model in which 8 E2 homotrimers and 12 E2-E2-E3BP heterotrimers assemble into a pseudoicosahedral particle such that the 12 E3BP molecules form six E3BP-E3BP intertrimer interfaces distributed tetrahedrally within the 60-subunit core. The even distribution of E3 subunits in the peripheral shell of PDHc guarantees maximum enzymatic activity of the megaenzyme.


Subject(s)
Cryoelectron Microscopy , Pyruvate Dehydrogenase Complex , Humans , Pyruvate Dehydrogenase Complex/metabolism , Pyruvate Dehydrogenase Complex/chemistry , Models, Molecular , Dihydrolipoamide Dehydrogenase/metabolism , Dihydrolipoamide Dehydrogenase/chemistry , Protein Multimerization , Protein Binding , Protein Subunits/metabolism , Protein Subunits/chemistry , Dihydrolipoyllysine-Residue Acetyltransferase/metabolism , Dihydrolipoyllysine-Residue Acetyltransferase/chemistry
3.
Nucleic Acids Res ; 52(15): 9028-9048, 2024 Aug 27.
Article in English | MEDLINE | ID: mdl-39041433

ABSTRACT

Increasingly many studies reveal how ribosome composition can be tuned to optimally translate the transcriptome of individual cell types. In this study, we investigated the expression pattern, structure within the ribosome and effect on protein synthesis of the ribosomal protein paralog 39L (RPL39L). With a novel mass spectrometric approach we revealed the expression of RPL39L protein beyond mouse germ cells, in human pluripotent cells, cancer cell lines and tissue samples. We generated RPL39L knock-out mouse embryonic stem cell (mESC) lines and demonstrated that RPL39L impacts the dynamics of translation, to support the pluripotency and differentiation, spontaneous and along the germ cell lineage. Most differences in protein abundance between WT and RPL39L KO lines were explained by widespread autophagy. By CryoEM analysis of purified RPL39 and RPL39L-containing ribosomes we found that, unlike RPL39, RPL39L has two distinct conformations in the exposed segment of the nascent peptide exit tunnel, creating a distinct hydrophobic patch that has been predicted to support the efficient co-translational folding of alpha helices. Our study shows that ribosomal protein paralogs provide switchable modular components that can tune translation to the protein production needs of individual cell types.


Subject(s)
Protein Biosynthesis , Protein Folding , Ribosomal Proteins , Ribosomes , Ribosomal Proteins/metabolism , Ribosomal Proteins/genetics , Ribosomal Proteins/chemistry , Animals , Mice , Humans , Ribosomes/metabolism , Protein Conformation, alpha-Helical , Mice, Knockout , Mouse Embryonic Stem Cells/metabolism , Cell Differentiation/genetics
4.
Dev Cell ; 59(14): 1876-1891.e7, 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-38788715

ABSTRACT

Amyloids are known as irreversible aggregates associated with neurodegenerative diseases. However, recent evidence shows that a subset of amyloids can form reversibly and fulfill essential cellular functions. Yet, the molecular mechanisms regulating functional amyloids and distinguishing them from pathological aggregates remain unclear. Here, we investigate the conserved principles of amyloid reversibility by studying the essential metabolic enzyme pyruvate kinase (PK) in yeast and human cells. We demonstrate that yeast PK (Cdc19) and human PK (PKM2) form reversible amyloids through a pH-sensitive amyloid core. Stress-induced cytosolic acidification promotes aggregation via protonation of specific glutamate (yeast) or histidine (human) residues within the amyloid core. Mutations mimicking protonation cause constitutive PK aggregation, while non-protonatable PK mutants remain soluble even upon stress. Physiological PK aggregation is coupled to metabolic rewiring and glycolysis arrest, causing severe growth defects when misregulated. Our work thus identifies an evolutionarily conserved, potentially widespread mechanism regulating functional amyloids during stress.


Subject(s)
Amyloid , Pyruvate Kinase , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Humans , Hydrogen-Ion Concentration , Pyruvate Kinase/metabolism , Pyruvate Kinase/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae/genetics , Amyloid/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics , Mutation/genetics , Glycolysis , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics
5.
Nat Chem Biol ; 20(8): 1044-1052, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38467846

ABSTRACT

Phase transitions are important to understand cell dynamics, and the maturation of liquid droplets is relevant to neurodegenerative disorders. We combined NMR and Raman spectroscopies with microscopy to follow, over a period of days to months, droplet maturation of the protein fused in sarcoma (FUS). Our study reveals that the surface of the droplets plays a critical role in this process, while RNA binding prevents it. The maturation kinetics are faster in an agarose-stabilized biphasic sample compared with a monophasic condensed sample, owing to the larger surface-to-volume ratio. In addition, Raman spectroscopy reports structural differences upon maturation between the inside and the surface of droplets, which is comprised of ß-sheet content, as revealed by solid-state NMR. In agreement with these observations, a solid crust-like shell is observed at the surface using microaspiration. Ultimately, matured droplets were converted into fibrils involving the prion-like domain as well as the first RGG motif.


Subject(s)
RNA-Binding Protein FUS , RNA-Binding Protein FUS/chemistry , RNA-Binding Protein FUS/metabolism , Humans , Protein Conformation, beta-Strand , Spectrum Analysis, Raman , Phase Transition , Surface Properties , Kinetics , Magnetic Resonance Spectroscopy/methods
6.
Transl Vis Sci Technol ; 13(2): 8, 2024 02 01.
Article in English | MEDLINE | ID: mdl-38345551

ABSTRACT

Purpose: To evaluate early detection of retinal hemangioblastomas (RHs) in von Hippel-Lindau disease (VHLD) with widefield optical coherence tomography angiography (wOCTA) compared to the standard of care in ophthalmologic VHLD screening in a routine clinical setting. Methods: We conducted prospective comparisons of three screening methods: wOCTA, standard ophthalmoscopy, and fluorescein angiography (FA), which was performed only in uncertain cases. The numbers of detected RHs were compared among the three screening methods. The underlying causes for the lack of detection were investigated. Results: In 91 eyes (48 patients), 67 RHs were observed (mean, 0.74 ± 1.59 RH per eye). FA was performed in eight eyes. Ophthalmoscopy overlooked 25 of the 35 RHs detected by wOCTA (71.4%) due to the background color of the choroid (n = 5), small tumor size (n = 13), masking by a bright fundus reflex (n = 2), and masking by surrounding retinal scars (n = 5). However, wOCTA missed 29 RHs due to peripheral location (43.3%). The overall detection rates were up to 37% on the basis of ophthalmoscopy alone, up to 52% for wOCTA, and 89% for FA. Within the retinal area covered by wOCTA, the detection rates were up to 46.7% for ophthalmoscopy alone, up to 92.1% for wOCTA, and 73.3% for FA. Conclusions: The overall low detection rate of RHs using wOCTA is almost exclusively caused by its inability to visualize the entire peripheral retina. Therefore, in unclear cases, FA is necessary after ophthalmoscopy. Translational Relevance: Within the imageable retinal area, wOCTA shows a high detection rate of RHs and therefore may be suitable to improve screening for RHs in VHLD.


Subject(s)
Hemangioblastoma , Retinal Neoplasms , von Hippel-Lindau Disease , Humans , Tomography, Optical Coherence/methods , von Hippel-Lindau Disease/diagnostic imaging , Hemangioblastoma/diagnostic imaging , Retinal Neoplasms/diagnostic imaging , Fluorescein Angiography/methods
7.
Int Ophthalmol ; 43(12): 4551-4562, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37684398

ABSTRACT

PURPOSE: Hypoxia-inducible factors (HIFs) are considered to play a significant role in the pathogenesis of pterygium. The aim of this study was to investigate the relative expression or immunoreactivity of HIF1α and HIF2α in the epithelium of primary pterygium, recurrences and healthy conjunctiva. METHODS: Immunohistochemical staining was performed with antibodies against HIF1α and HIF2α, respectively, on 55/84 primary pterygium specimens, 6/28 recurrences and 20/20 control tissues (healthy conjunctiva). RESULTS: Immunohistochemical staining revealed lower epithelial immunoreactivity of HIF1α and HIF2α in both primary pterygium (11% and 38%) and recurrences (18% and 21%) when compared to healthy conjunctival tissue (46% and 66%). Differences between immunoreactivity of HIF1α and of HIF2α in primary pterygium and controls were each highly significant (p < .001). Within the group of primary pterygium, epithelial immunoreactivity of HIF2α (38%) was significantly higher than that of HIF1α (11%). In recurrent pterygium and healthy conjunctiva, immunoreactivity levels of HIF2α were higher than those of HIF1α as well; however, differences between both isoforms were not significant. CONCLUSION: Our study shows evidence that the higher expressed epithelial HIF2α, rather than HIF1α, and the balance between both HIF isoforms might be relevant factors associated with pathogenesis of primary pterygium. Modulation of HIF2α levels and activity may thus offer a new therapeutic approach to the treatment of advancing pterygium where the initial stage with its HIF1-peak has already passed.


Subject(s)
Pterygium , Humans , Pterygium/metabolism , Epithelium/pathology , Conjunctiva/pathology , Protein Isoforms/metabolism
8.
Nat Commun ; 14(1): 1574, 2023 03 22.
Article in English | MEDLINE | ID: mdl-36949039

ABSTRACT

The discovery of nackednaviruses provided new insight into the evolutionary history of the hepatitis B virus (HBV): The common ancestor of HBV and nackednaviruses was non-enveloped and while HBV acquired an envelope during evolution, nackednaviruses remained non-enveloped. We report the capsid structure of the African cichlid nackednavirus (ACNDV), determined by cryo-EM at 3.7 Å resolution. This enables direct comparison with the known capsid structures of HBV and duck HBV, prototypic representatives of the mammalian and avian lineages of the enveloped Hepadnaviridae, respectively. The sequence identity with HBV is 24% and both the ACNDV capsid protein fold and the capsid architecture are very similar to those of the Hepadnaviridae and HBV in particular. Acquisition of the hepadnaviral envelope was thus not accompanied by a major change in capsid structure. Dynamic residues at the spike tip are tentatively assigned by solid-state NMR, while the C-terminal domain is invisible due to dynamics. Solid-state NMR characterization of the capsid structure reveals few conformational differences between the quasi-equivalent subunits of the ACNDV capsid and an overall higher capsid structural disorder compared to HBV. Despite these differences, the capsids of ACNDV and HBV are structurally highly similar despite the 400 million years since their separation.


Subject(s)
Capsid Proteins , Hepadnaviridae , Animals , Capsid Proteins/metabolism , Hepatitis B virus/genetics , Hepatitis B virus/metabolism , Capsid/metabolism , Hepadnaviridae/metabolism , Mammals/metabolism
9.
Int Ophthalmol ; 43(7): 2397-2405, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36670265

ABSTRACT

PURPOSE: Single center study to evaluate the incidence and long-term outcome of laser pointer maculopathy (LPM). METHODS: Medical records of 909,150 patients visiting our institution between 2007 and 2020 were screened in our electronic patient record system using the keywords "laserpointer," "laser pointer," and "solar." RESULTS: Eight patients (6/2 male/female, 11 eyes) with a history of LPM were identified by fundoscopy and optical coherence tomography (OCT), all of whom were children (6/2 male/female). Mean age at injury was 12.1 years (range 6-16). Five children (62.5%) were injured between 2019 and 2020, three (37.5%) between 2007 and 2018. Median best-corrected visual acuity (BCVA) of affected eyes at first presentation was 20/25 (range 20/50-20/16). Follow-up examination was performed in seven children (10 eyes) with a median follow-up period of 18 months (range 0.5-96). BCVA improved in 4 children (5 eyes; BCVA at follow-up 20/22.5, range 20/40-20/16). Three of these four children were treated with oral steroids. OCT revealed acute signs such as intraretinal fluid to resolve quickly, while outer retinal disruption persisted until the last follow-up in eight of eleven eyes. These lesions resembled lesions of patients with solar retinopathy of which seven cases (11 eyes) were identified between 2007 and 2020. CONCLUSION: Readily available consumer laser pointers can damage the retina and the underlying retinal pigment epithelium, possibly leading to long-lasting visual impairments. The number of laser pointer injuries has increased over the last years. Therefore, access to laser pointers for children should be strictly controlled.


Subject(s)
Macular Degeneration , Retinal Diseases , Humans , Female , Male , Child , Adolescent , Incidence , Visual Acuity , Retinal Diseases/diagnosis , Retinal Diseases/epidemiology , Retinal Diseases/etiology , Lasers , Macular Degeneration/complications , Tomography, Optical Coherence/methods
10.
Graefes Arch Clin Exp Ophthalmol ; 261(4): 1159-1166, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36255550

ABSTRACT

PURPOSE: We herein compare topical interferon alpha 2b (IFN-α2b) to topical mitomycin C (MMC) in the adjuvant management after excision of primary acquired melanosis with atypia (PAM) and melanoma of the conjunctiva/cornea (CM). METHODS: We included 25 tumors from 25 patients (six with PAM and 19 with CM). After surgical excision, four patients started with adjuvant IFN-α2b (two in combination with radiotherapy), 19 with MMC, and two with radiotherapy alone. Five patients were switched from initial MMC/radiotherapy to IFN-α2b during follow-up. Efficacy was assessed via time to tumor recurrence and initial therapy response. RESULTS: With initial IFN-α2b, three patients (3/4, two with additional radiotherapy) showed complete remission (follow-up: 1478-1750 days) and one recurrence (1/4) was noted after 492 days. With initial MMC, no recurrence was recorded in 15 of the 19 patients (follow-up: 99-4732 days). Five patients were switched from MMC or radiotherapy to IFN-α2b: two patients showed complete remission (2/5), while another two (2/5) experienced recurrences and remained without recurrence after repeated courses of IFN-α2b (follow-up: 1798 and 1973 days). Only one patient showed incomplete response. Adverse effects were recorded in five patients, all received MMC. CONCLUSION: Topical IFN-α2b (arguably together with radiotherapy) may be a viable alternative to MMC in PAM and CM. We observed fewer side effects at similar response rates. However, when response to MMC was poor, IFN-α2b may also be of limited utility.


Subject(s)
Conjunctival Neoplasms , Melanosis , Humans , Mitomycin , Conjunctival Neoplasms/drug therapy , Conjunctival Neoplasms/pathology , Melanosis/diagnosis , Melanosis/drug therapy , Neoplasm Recurrence, Local , Interferon-alpha/therapeutic use , Adjuvants, Immunologic
11.
Nucleic Acids Res ; 50(11): 6300-6312, 2022 06 24.
Article in English | MEDLINE | ID: mdl-35687109

ABSTRACT

Heterogenous nuclear ribonucleoproteins (hnRNPs) are abundant proteins implicated in various steps of RNA processing that assemble on nuclear RNA into larger complexes termed 40S hnRNP particles. Despite their initial discovery 55 years ago, our understanding of these intriguing macromolecular assemblies remains limited. Here, we report the biochemical purification of native 40S hnRNP particles and the determination of their complete protein composition by label-free quantitative mass spectrometry, identifying A-group and C-group hnRNPs as the major protein constituents. Isolated 40S hnRNP particles dissociate upon RNA digestion and can be reconstituted in vitro on defined RNAs in the presence of the individual protein components, demonstrating a scaffolding role for RNA in nucleating particle formation. Finally, we revealed their nanometer scale, condensate-like nature, promoted by intrinsically disordered regions of A-group hnRNPs. Collectively, we identify nuclear 40S hnRNP particles as novel dynamic biomolecular condensates.


Subject(s)
Biomolecular Condensates , Heterogeneous-Nuclear Ribonucleoproteins , Cell Nucleus/metabolism , Heterogeneous-Nuclear Ribonucleoproteins/genetics , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , RNA/metabolism
12.
Proc Natl Acad Sci U S A ; 119(3)2022 01 18.
Article in English | MEDLINE | ID: mdl-35042777

ABSTRACT

Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing mitochondrial inner membrane proteins responsible for oxidative phosphorylation. Although mitoribosomes from different organisms exhibit considerable structural variations, recent insights into mitoribosome assembly suggest that mitoribosome maturation follows common principles and involves a number of conserved assembly factors. To investigate the steps involved in the assembly of the mitoribosomal small subunit (mt-SSU) we determined the cryoelectron microscopy structures of middle and late assembly intermediates of the Trypanosoma brucei mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution, respectively. We identified five additional assembly factors that together with the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with functionally important regions of the rRNA, including the decoding center, thereby preventing premature mRNA or large subunit binding. Structural comparison of assembly intermediates with mature mt-SSU combined with RNAi experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly process, where modular exchange of ribosomal proteins and assembly factors together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation during the final steps of assembly.


Subject(s)
Mitochondrial Proteins/chemistry , Mitochondrial Ribosomes/chemistry , Oxidative Phosphorylation , RNA, Ribosomal/chemistry , Ribosomal Proteins/chemistry , Ribosome Subunits/chemistry , Cell Line , Cryoelectron Microscopy , Mitochondria/metabolism , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Mitochondrial Ribosomes/metabolism , Models, Molecular , RNA, Ribosomal/genetics , RNA, Ribosomal/metabolism , Ribosomal Proteins/genetics , Ribosomal Proteins/metabolism , Ribosome Subunits/genetics , Ribosome Subunits/metabolism , Trypanosoma brucei brucei/genetics , Trypanosoma brucei brucei/metabolism
13.
EMBO Rep ; 22(11): e52981, 2021 11 04.
Article in English | MEDLINE | ID: mdl-34647674

ABSTRACT

The human GID (hGID) complex is a conserved E3 ubiquitin ligase regulating diverse biological processes, including glucose metabolism and cell cycle progression. However, the biochemical function and substrate recognition of the multi-subunit complex remain poorly understood. Using biochemical assays, cross-linking mass spectrometry, and cryo-electron microscopy, we show that hGID engages two distinct modules for substrate recruitment, dependent on either WDR26 or GID4. WDR26 and RanBP9 cooperate to ubiquitinate HBP1 in vitro, while GID4 is dispensable for this reaction. In contrast, GID4 functions as an adaptor for the substrate ZMYND19, which surprisingly lacks a Pro/N-end degron. GID4 substrate binding and ligase activity is regulated by ARMC8α, while the shorter ARMC8ß isoform assembles into a stable hGID complex that is unable to recruit GID4. Cryo-EM reconstructions of these hGID complexes reveal the localization of WDR26 within a ring-like, tetrameric architecture and suggest that GID4 and WDR26/Gid7 utilize different, non-overlapping binding sites. Together, these data advance our mechanistic understanding of how the hGID complex recruits cognate substrates and provides insights into the regulation of its E3 ligase activity.


Subject(s)
High Mobility Group Proteins , Ubiquitin-Protein Ligases , Binding Sites , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cryoelectron Microscopy , High Mobility Group Proteins/metabolism , Humans , Repressor Proteins/metabolism , Substrate Specificity , Ubiquitin-Protein Ligases/metabolism , Ubiquitination
14.
Clin Epidemiol ; 13: 581-592, 2021.
Article in English | MEDLINE | ID: mdl-34285592

ABSTRACT

BACKGROUND/AIMS: Surgical procedures in ophthalmology underlie variations over different time periods and are strongly dependent on the technical process and the invention of innovative surgical techniques. Especially, in glaucoma surgery a lot of surgical devices and techniques have been introduced during the last years. Until now, the use of these newer techniques has not been shown on a robust data basis. We herein present the numbers of different types of glaucoma surgeries performed at German hospitals between 2006 and 2018. METHODS AND DESIGN: The quality reports of hospitals in Germany from 2006 to 2018 were analyzed concerning all procedural codes for glaucoma surgery and intervention. Especially, the change in usage of "classical" and "modern" surgical techniques (MIGS: "minimally invasive glaucoma surgery") or devices was compared. RESULTS: The number of glaucoma procedures performed increased by 75% from 27,811 in 2006 to 48,794 in 2018. Absolute numbers of trabeculectomies, goniotomies, ab externo trabeculotomies and to a certain level cyclodestructive procedures decreased during the examined years while use of MIGS has increased in absolute and relative numbers since 2012. From 2015 a strong increase in the usage of XEN implants could be seen. Drainage implants (such as Baerveldt/Ahmed) showed stable absolute numbers over the time period covered. Absolute numbers of laser trabeculoplasty peaked in 2014 and decreased afterwards. Iridotomies and iridectomies increased by 120%/248% over the whole period. CONCLUSION: Our data show a trend towards the modern surgical options and especially MIGS during the recent years. Classical procedures showed a decrease in total numbers emphasized from 2013. These numbers confirm the assumption that modern glaucoma surgery is becoming more and more popular and established in German hospitals.

15.
Nucleic Acids Res ; 49(11): 6389-6398, 2021 06 21.
Article in English | MEDLINE | ID: mdl-34086932

ABSTRACT

Biogenesis of ribosomal subunits involves enzymatic modifications of rRNA that fine-tune functionally important regions. The universally conserved prokaryotic dimethyltransferase KsgA sequentially modifies two universally conserved adenosine residues in helix 45 of the small ribosomal subunit rRNA, which is in proximity of the decoding site. Here we present the cryo-EM structure of Escherichia coli KsgA bound to an E. coli 30S at a resolution of 3.1 Å. The high-resolution structure reveals how KsgA recognizes immature rRNA and binds helix 45 in a conformation where one of the substrate nucleotides is flipped-out into the active site. We suggest that successive processing of two adjacent nucleotides involves base-flipping of the rRNA, which allows modification of the second substrate nucleotide without dissociation of the enzyme. Since KsgA is homologous to the essential eukaryotic methyltransferase Dim1 involved in 40S maturation, these results have also implications for understanding eukaryotic ribosome maturation.


Subject(s)
Adenosine/metabolism , Escherichia coli/enzymology , Methyltransferases/chemistry , Adenosine/chemistry , Cryoelectron Microscopy , Methyltransferases/metabolism , Models, Molecular , Protein Conformation , Ribosome Subunits, Small, Bacterial/chemistry , Substrate Specificity
17.
Sci Adv ; 7(21)2021 05.
Article in English | MEDLINE | ID: mdl-34020957

ABSTRACT

The conserved signal recognition particle (SRP) cotranslationally delivers ~30% of the proteome to the eukaryotic endoplasmic reticulum (ER). The molecular mechanism by which eukaryotic SRP transitions from cargo recognition in the cytosol to protein translocation at the ER is not understood. Here, structural, biochemical, and single-molecule studies show that this transition requires multiple sequential conformational rearrangements in the targeting complex initiated by guanosine triphosphatase (GTPase)-driven compaction of the SRP receptor (SR). Disruption of these rearrangements, particularly in mutant SRP54G226E linked to severe congenital neutropenia, uncouples the SRP/SR GTPase cycle from protein translocation. Structures of targeting intermediates reveal the molecular basis of early SRP-SR recognition and emphasize the role of eukaryote-specific elements in regulating targeting. Our results provide a molecular model for the structural and functional transitions of SRP throughout the targeting cycle and show that these transitions provide important points for biological regulation that can be perturbed in genetic diseases.

18.
Nucleic Acids Res ; 49(11): e63, 2021 06 21.
Article in English | MEDLINE | ID: mdl-33677607

ABSTRACT

U1 small nuclear ribonucleoparticle (U1 snRNP) plays a central role during RNA processing. Previous structures of U1 snRNP revealed how the ribonucleoparticle is organized and recognizes the pre-mRNA substrate at the exon-intron junction. As with many other ribonucleoparticles involved in RNA metabolism, U1 snRNP contains extensions made of low complexity sequences. Here, we developed a protocol to reconstitute U1 snRNP in vitro using mostly full-length components in order to perform liquid-state NMR spectroscopy. The accuracy of the reconstitution was validated by probing the shape and structure of the particle by SANS and cryo-EM. Using an NMR spectroscopy-based approach, we probed, for the first time, the U1 snRNP tails at atomic detail and our results confirm their high degree of flexibility. We also monitored the labile interaction between the splicing factor PTBP1 and U1 snRNP and validated the U1 snRNA stem loop 4 as a binding site for the splicing regulator on the ribonucleoparticle. Altogether, we developed a method to probe the intrinsically disordered regions of U1 snRNP and map the interactions controlling splicing regulation. This approach could be used to get insights into the molecular mechanisms of alternative splicing and screen for potential RNA therapeutics.


Subject(s)
Ribonucleoprotein, U1 Small Nuclear/chemistry , Binding Sites , Ligands , Magnetic Resonance Spectroscopy , RNA Splicing Factors/metabolism , Ribonucleoprotein, U1 Small Nuclear/metabolism
19.
Acta Ophthalmol ; 99(8): e1492-e1500, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33720516

ABSTRACT

BACKGROUND/AIMS: Retinal haemangioblastomas (RH) remain a major cause of visual impairment in patients with von Hippel-Lindau (VHL) disease. Identification of genotype-phenotype correlation is an important prerequisite for better management, treatment and prognosis. METHODS: Retrospective, single-centre cohort study of 200 VHL patients. Genetic data and date of onset of RH, central nervous system haemangioblastomas (CNSH), pheochromocytoma/paraganglioma (PPGL), clear cell renal cell carcinoma (ccRCC) and pancreatic neuroendocrine neoplasm (PNEN) were collected. The number and locations of RH were recorded. RESULTS: The first clinical finding occurred at an age of 26 ± 14 years (y) [mean ± SD]. In 91 ± 3% (95% CI 88-94) of the patients, at least one RH occur until the age of 60y. A total of 42 different rare VHL gene variants in 166 patients were detected. A higher age-related incidence of RH, CNSH, ccRCC and PNEN was detected in patients with a truncating variant (TV) compared to patients with a single amino-acid substitution/deletion (AASD) (all p < 0.01), while it is reverse for PPGL (p < 0.01). Patients with a TV showed 0.10 ± 0.15 RH per y during their lifetime compared to 0.05 ± 0.07 in patients with AASD (p < 0.02). The median enucleation/phthisis-free survival time in patients with a TV was 56y (95% CI 50-62) compared to 78y (95% CI 75-81) in patients with AASD (p < 0.02). CONCLUSION: Compared to patients with AASD, patients with a TV develop RH, CNSH, ccRCC and PNEN earlier. They experience a higher number of RH and bear a higher risk of enucleation/phthisis. Thus, patients with a TV might be considered for a more intensive ophthalmological monitoring.


Subject(s)
Genetic Association Studies/methods , Genetic Predisposition to Disease , Hemangioblastoma/etiology , Retina/diagnostic imaging , Retinal Neoplasms/etiology , von Hippel-Lindau Disease/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Child , DNA Mutational Analysis , Female , Fluorescein Angiography/methods , Follow-Up Studies , Fundus Oculi , Germany/epidemiology , Hemangioblastoma/diagnosis , Hemangioblastoma/epidemiology , Humans , Male , Middle Aged , Morbidity/trends , Mutation , Retinal Neoplasms/diagnosis , Retinal Neoplasms/epidemiology , Retrospective Studies , Tomography, Optical Coherence/methods , Von Hippel-Lindau Tumor Suppressor Protein/genetics , Von Hippel-Lindau Tumor Suppressor Protein/metabolism , Young Adult , von Hippel-Lindau Disease/complications , von Hippel-Lindau Disease/epidemiology
20.
World Neurosurg ; 149: e1007-e1016, 2021 05.
Article in English | MEDLINE | ID: mdl-33476778

ABSTRACT

OBJECTIVE: The choice of surgical technique in sight-threatening Grave orbitopathy remains controversial. Available data are mostly derived from mixed cohorts with multiple surgical indications and techniques. The authors assessed predictors for visual outcome after standardized pterional orbital decompression for dysthyroid optic neuropathy. METHODS: Retrospective analysis of 62 pterional orbital decompressions performed on 40 patients with dysthyroid optic neuropathy. RESULTS: Visual acuity improved by an average of 3.8 lines in eyes with preoperative visual impairment (95% confidence interval [CI]: 1.8-5.8 lines, P < 0.001) and remained stable in eyes without prior visual impairment (95% CI -1.3 to 1 line, P = 0.81). Proptosis was reduced by an average of 3.1 mm (95% CI 1.8-4.3 mm, P < 0.001). Higher degrees of proptosis were predictive of worse visual outcomes (P = 0.017). New-onset diplopia developed in 2 patients, while previous diplopia resolved after surgery in 6 patients. CONCLUSIONS: This cohort is the largest series of pterional orbit decompressions and the first to focus exclusively on dysthyroid neuropathy. Complication rates were low. Decompression surgery was highly effective at restoring and maintaining visual acuity in patients with dysthyroid optic neuropathy.


Subject(s)
Decompression, Surgical/methods , Graves Ophthalmopathy/surgery , Orbit/surgery , Adult , Aged , Aged, 80 and over , Diplopia/etiology , Exophthalmos/etiology , Exophthalmos/surgery , Female , Humans , Male , Middle Aged , Postoperative Complications/epidemiology , Postoperative Complications/prevention & control , Retrospective Studies , Treatment Outcome , Vision, Ocular , Visual Acuity
SELECTION OF CITATIONS
SEARCH DETAIL